HARVARD UNIVERSITY Library of the Museum of Comparative Zoology The Great Basin Naturalist VOLUME 47, 1987 EDITOR: Stephen L. Wood Published At Brigham Young University, by Brigham Young University TABLE OF CONTENTS Volume 47 Number 1 — 31 January 1987 Competition for food and space in a heteromyid community in the Great Basin Desert. Cliff A. Lemen and Patricia W. Freeman 1 Sequence of epiphyseal fusion in the Rocky Mountain bighorn sheep. Danny Walker 7 Parasites of mottled sculpin, Cottus bairdi Girard, from five locations in Utah and Wasatch counties, Utah. Richard A. Heckmann, Allen K. Kimball, and JeflFery A. Short 13 Effects of artificial shading on distribution and abundance of juvenile chinook salmon (Oncorhynchiis tshawytscha) . William R. Meehan, Merlyn A. Brusven, and John F. Ward 22 Drosophila pseudoobscura (Diptera: Drosophilidae) of the Great Basin IV: a release experiment at Bryce Canyon. Monte E. Turner 32 Robber flies of Utah (Diptera: Asilidae). C. Riley Nelson 38 Elemental compartmentalization in seeds oiAtriplex triangularis and Atriplex confertifo- lia. M. A. Khan, D. J. Weber, and W. M. Hess 91 Plant community changes within a mature pinyon-juniper woodland. Dennis D. Austin 96 Consumption of fresh alfalfa hay by mule deer and elk. Dennis D. Austin and Philip J. Urness 100 Helminth parasites of the Wyoming ground squirrel, Spermophilus elegans Kennicott, 1863. Larry M. Shults and Nancy L. Stanton 103 Observations of captive Rocky Mountain mule deer behavior. Douglas K. Halford, W. John Arthur 111, and A. William Alldredge 105 Effects of osmotic potential, potassium chloride, and sodium chloride on germination of greasewood (Sarcobatiis vermicidatus). James T. Romo and Marshall R. Hafer- kamp 110 Big sagebrush (Artemisia tridentata vaseijana) and longleaf snowberry (Symphoricarpos oreophilus) plant associations in northeastern Nevada. Paul T. Tueller and Richard E. Eckert, Jr 117 Habitat and community relationships of cliffrose (Cowania mexicana var. stansburiana) in central Utah. K. P. Price and J. D. Brotherson 132 Alpine vascular flora of the Ruby Range, West Elk Mountains, Colorado. Emily L. Hartman and Mary Lou Rottman 152 Douglas-fir dwarf mistletoe parasitizing Pacific silver fir in northern California. Robert L. Mathiasen and Larry Loftis 161 A disjunct ponderosa pine stand in southeastern Oregon. Arthur McKee and Donald Knutson 163 Notes on American Sitona (Coleoptera: Curculionidae), with three new species. Vasco M. Tanner 168 Number 2—30 April 1987 Ecological comparison of sympatric populations of sand lizards (Cophosaurtis texanus and Callisaurus draconoides). Donald D. Smith, Philip A. Medica, and Sherburn R. Sanborn 175 Zoogeography of Great Basin butterflies: patterns of distribution and differentiation. George T. Austin and Dennis D. Murphy 186 Reproductive ecology of black-tailed prairie dogs in Montana. Craig J. Knowles 202 Field clinic procedures for diagnosing Echinococciis granulosus in dogs. Ferron L. Andersen and M. John Ramsay 207 Seed germination characteristics o( Chrysotharnnus nauseosus ssp. viridulus (Astereae, Asteraceae). M. A. Khan, N. Sankhla, D. J. Weber, and E. D. McArthur 220 Development and longevity of ephemeral and perennial leaves on Artemisia tridentata Nutt. ssp. wyomingensis. Richard F. Miller and Leila M. Shultz 227 Pygmy rabbits in the Colorado River drainage. C. L. Pritchett, J. A. Nilsen, M. P. Coffeen, and H. D. Smith 231 Effects of land clearing on bordering winter annual populations in the Mohave Desert. Richard Hunter, F. B. Turner, R. G. Lindberg, and Katherine Bell Hunter 234 Occurrence of the musk ox, Syinbos cavifrons, from southeastern Idaho and comments on the genus Bootheriujii. Michael E. Nelson and James H. Madsen, Jr 239 Effects of logging on habitat quality and feeding patterns of Abert squirrels. Jordan C. Pederson, R. C. Farentinos, and Victoria M. Littlefield 252 Parasites of the cutthroat trout, Sahno clarki, and longnose suckers, Catostomus catostomus, from Yellowstone Lake, Wyoming. R. A. Heckmann and H. L. Ching. 259 Burrows of the sagebrush vole {Lemmiscus curtatus) in southeastern Idaho. Tim R. Mullican and Barry L. Keller 276 Spider fauna of selected wild sunflower species sites in the southwest United States. G.J. Seiler, G. Zolnerowich, N. V. Horner, and C. E. Rogers 280 Leptophlebiidae of the southwestern United States and northwestern Mexico (Insecta: Ephemeroptera). Richard K. Allen and Chad M. Murvosh 283 Flora ofthe Orange Cliffs of Utah. L. M. Shultz, E. E. Neely, and J. S. Tuhy 287 Evaluation of the improvement in sensitivity of nested frequency plots to vegeta- tional change by summation. Stuart D. Smith, Stephen C. Bunting, and M. Hironaka 299 Notes on mycophagy in four species of mice in the genus Peromyscus. Chris Maser and Zane Maser 308 Bee visitors of sweetvetch, Hedysarum horeale boreale (Leguminosae), and their pollen- collecting activities. Vincent J. Tepedino and Mark Stackhouse 314 Observations on natural enemies of western spruce budworm {Choristoneura occiden- talis Freeman) (Lepidoptera, Tortricidae) in the Rocky Mountain area. Howard E. Evans '. 319 Plant community zonation in response to soil gradients in a saline meadow near Utah Lake, Utah County, Utah. Jack D. Brotherson 322 Age in relationship to stem circumference and stem diameter in cliflFrose {Cowania mexicana var. stanshuriana) in central Utah. J. D. Brotherson, K. P. Price, and L. O'Rourke 334 Demography of black-tailed prairie dog populations reoccupying sites treated with rodenticide. R. P. Cincotta, D. W. Uresk, and R. M. Hansen 339 Western painted turtle in Grant County, Oregon. Jeffrey H. Black and Andrew H. Black. 344 American swallow bug, Oeciacus vicarius Horvath (Hemiptera: Cimicidae), in Hirundo rustica and Petrochelidon pyrrhonota nests in west central Colorado. Thomas Orr and Gary McCallister 345 Pseudocrossidium aureum (Bartr.) Zand. (Pottiaceae, Musci) new to Utah. John R. Spence 347 Number 3—31 July 1987 Relationship of western juniper stem conducting tissue and basal circumference to leaf area and biomass. Richard F. Miller, Lee E. Eddleman, and Raymond F. Angell 349 Parasites of the bowhead whale, Balaena mysticetus. Richard A. Heckmann, Lauritz A. Jensen, Robert G. Warnock, and Bruce Coleman 355 Reproduction of the prairie skink, Eumeces septentrionalis , in Nebraska. Louis A. Somma 373 List of Idaho Scolytidae (Coleoptera) and notes on new records. Malcolm M. Furniss and James B. Johnson 375 Lizards and turtles of western Chihuahua. Wilmer W. Tanner 383 Dry-year grazing and Nebraska sedge (Carex nebraskensis). Raymond D. Ratliff and Stanley E. Westfall 422 Diamond Pond, Harney County, Oregon: vegetation history and water table in the eastern Oregon desert. Peter Ernest Wigand 427 Comparison of habitat attributes at sites of stable and declining long-billed curlew populations. Jean F. Cochran and Stanley H. Anderson 459 Estimates of site potential for ponderosa pine based on site index for several southwestern habitat types. Robert L. Mathiasen, Elizabeth A. Blake, and Carleton B. Edmin- ster 467 Soil nematodes of northern Rocky Mountain ecosystems: genera and biomasses. T. Weaver and J. Smolik 473 Evidence for variability in spawning behavior of interior cutthroat trout in response to environmental uncertainty. Rodger L. Nelson, William S. Platts, and Osborne Casey 480 Niche pattern in a Great Basin rodent fauna. Edward H. Robey, Jr., H. Duane Smith, and Mark C. Belk 488 Planting depth of Hobble Creek' mountain big sagebrush seed. Tracy L. C. Jacobson and Bruce L. Welch 497 Annotated inventory of invertebrate populations of an alpine lake and stream chain in Colorado. John H. Bushnell, Susan Q. Foster, and Bruce M. Wahle 500 Distribution of vertebrates of the Bighorn Canyon National Recreation Area. Stanley H. Anderson, Wayne A. Hubert, Craig Patterson, Alan J. Redder, and David Duvall. 512 Number 4—31 October 1987 Records of exotic fishes from Idaho and Wyoming. Walter R. Courtenay, Jr., C. Richard Robins, Reeve M. Bailey, and James E. Deacon 523 Revision of Sahniocarpon harrisii Chitaley & Patil based on new specimens from the Deccan Intertrappean Beds of India. E. M. V. Nambudiri, William D. Tidwell, and Shya Chitaley 527 Maternal care of neonates in the prairie skink, Eumeces septentrionalis. Louis A. Somma. 536 Thermal tolerances and preferences of fishes of the Virgin River system (Utah, Arizona, Nevada). James E. Deacon, Paul B. Schumann, and Edward L. Stuenkel 538 Six new Scolytidae (Coleoptera) from Mexico. Stephen L. Wood 547 Genetic variation and population structure in the cliff chipmunk, Eutamias dorsalis, in • the Great Basin of western Utah. Martin L. Dobson, Clyde L. Pritchett, and Jack W. Sites, Jr 551 Observations on the ecology and trophic status of Lake Tahoe (Nevada and California, USA) based on the algae from three independent surveys (1965-1985). Sam L. VanLandingham 562 Zonation patterns in the vascular plant communities of Benton Hot Springs, Mono County, California. Jack D. Brotherson and Samuel D. Rushforth 583 New brachiosaur material from the Late Jurassic of Utah and Colorado. James A. Jensen. 592 Small-stone content of Mima mounds of the Columbia Plateau and Rocky Mountain regions: implications for mound origin. George W. Cox, Christopher G. Gakahu, and Douglas W. Allen 609 Type specimens of recent mammals in the Utah Museum of Natural History, University of Utah. Eric A. Rickart 620 Avian use of scoria rock outcrops. Mark A. Rumble 625 Colorado ground beetles (Coleoptera: Carabidae) from the Rotger Collection, University of Colorado Museum. Scott A. Elias 631 Winter habitat-use patterns of elk, mule deer, and moose in southwestern Wyoming. Olin O. Oedekoven and Fredrick G. Lindzey 638 Herbivorous and parasitic insect guilds associated with Great Basin wildrye {Elymus cinereus) in southern Idaho. Berta A. Youtie, Michael Stafford, and James B. Johnson 644 Effects of forest fuel smoke on dwarf mistletoe seed germination. G. Thomas Zimmerman and Richard D. Laven 652 Microvelia rasilis Drake in Arizona: a species new to the United States (Heteroptera: Veliidae). John T. Polhemus and Milton W. Sanderson 660 Index 661 WqS FHE GREAT BASIN NATURALIST Volume 47 No. 1 31 January 1987 Brigham Young University MCZ LIBRARY SEP 1 ^ ^987 UNIVERSITY 353*66^-* GREAT BASIN NATURALIST Editor. Stephen L. Wood, Department of Zoology, 290 Life Science Museum, Brigham Young University, Provo, Utah 84602. Editorial Board. Kimball T. Harper, Chairman, Botany and Range Science; Ferron L. An- dersen, Zoology; James R. Barnes, Zoology; Hal L. Black, Zoology; Jerran T. Fhnders, Botany and Range Science; Stanley L. Welsh, Botany and Range Science. All are at Brigham Young University. Ex Officio Editorial Board Members include Bruce N. Smith, Dean, College of Biological and Agricultural Sciences; Norman A. Darais, University Editor, University Publications; Stephen L. Wood, Editor, Great Basin Naturalist. The Great Basin Naturalist was founded in 1939. The journal is a publication of Brigham Young University. Previously unpublished manuscripts in Enghsh pertaining to the biological natural history of western North America are accepted. The Great Basin Naturalist Memoirs series was established in 1976 for scholarly works in biological natural history longer than can be accommodated in the parent publication. The Memoirs appears irregularly and bears no geographical restriction in subject matter. Manuscripts for both the Great Basin Naturalist and the Memoirs series will be accepted for publication only after exposure to peer review and approval of the editor. Subscriptions. Annual subscriptions to the Great Basin Naturalist are $25 for private individuals and $40 for institutions (outside the United States, $30 and $45, respectively), and $15 for student subscriptions. The price of single issues is $12. All back issues are in print and are available for sale. All matters pertaining to subscriptions, back issues, or other business should be directed to the Editor, Great Basin Naturalist, Brigham Young University, 290 Life Science Museum, Provo, Utah 84602. The Great Basin Naturalist Memoirs may be purchased from the same office at the rate indicated on the inside of the back cover of either journal. Scholarly Exchanges. Libraries or other organizations interested in obtaining either journal through a continuing exchange of scholarly publications should contact the Brigham Young University Exchange Librarian, Harold B. Lee Library, Provo, Utah 84602. Manuscripts. See Notice to Contributors on the inside back cover. 5-87 650 29178 ISSN 017-3614 The Great Basin Naturalist Published AT Provo, Utah, by Brigham Young University ISSN 0017-3614 Volume 47 31 January 1987 No. 1 COMPETITION FOR FOOD AND SPACE IN A HETEROMYID COMMUNITY IN THE GREAT BASIN DESERT Cliff A. Lemen' and Patricia W. Freeman' Abstr.\ct. — A series of removal experiments were performed on Dipodomijs merriami, D. microps, and Per- ognathus long.imembns to test for the importance of competition for food and microhabitats in a heteromyid community in the Great Basin Desert. Each of these species was removed singly to determine the short-term effects on the microhabitat preferences of the remaining species. We correctly predicted, based on differences in diet, that the removal of D. microps (a foliovore) would have no effect on D. merriami or P. longimembris (granivores). Using the dominance hierarchy theory, we correctly predicted that removal of a larger heteromyid, D. merriami, would have an effect on the microhabitat use of the smaller P. longimembris , but not vice versa. While our results offer strong evidence of competition for food and microhabitats, the short-term reactions were weak compared to the long-term reactions found in other studies of heteromyids. When a competitor is removed from a com- munity, the remaining species can react by an increase in density, a shift in the use of re- sources, or both. These reactions are evi- dence of competition, but they connote differ- ent aspects of the competitive interaction. Changes in densities indicate the strength of competition. Shifts in the use of resources indicate which resources are competed for and how competition has altered the funda- mental niches of competitors. Food and microhabitats have been pro- posed as the resources that are competed for by heteromyids (Rosenzweig 1973, Brown 1975). We tested for the intensity of this com- petition with a large-scale experiment that measured both changes in numbers of animals and use of resources when species were re- moved. This paper deals with changes in the use of resources after a perturbation. A com- panion paper (Lemen and Freeman 1986) dis- cusses the density responses to the removals. Our criteria for the presence of competition are changes in the use of microhabitats after species are removed. The use of changes in microhabitats as our test for competition is based on the success of removal experiments by Price (1978) and WondoUeck (1978). These studies showed short-term shifts in foraging patterns in heteromyids. We were particu- larly interested in repeating some of Price and Wondolleck's work because their results indi- cated that larger heteromyids have a short- term response to the removal of smaller het- eromyids. This result is inconsistent with our view of a dominance hierarchy based on size (Lemen and Freeman 1983, O'Farrell 1980, Frye 1983). Lemen and Freeman (1983) main- tained that short-term removals of a few weeks would not be long enough to affect resource levels. Any reaction to the removal is probably a direct response to the absence of the competitor and not a reaction mediated by changes in resources. Behavioral work (Blaustein 1974, Congdon 1974, Eisenberg 1963) indicates that heteromyids are highly aggressive both intra- and interspecifically. We hypothesized that this aggression might School of Biological Sciences and University of Nebraska State Museum, Universit) of Nebraska, Lincoln, Nebraska 68588. Great Basin Naturalist Vol. 47, No. 1 be the basis of a dominance hierarchy in which large species compelled small species to re- duce their use of some microhabitats. The dominance hierarchy hypothesis predicts that removal of large, aggressive heteromyids will produce a short-term shift in use of microhabi- tats by smaller heteromyids, but that removal of small, subordinate species will not produce a short-term reaction by larger species. To test our next hypothesis, that het- eromyids compete for food, we removed granivorous and nongranivorous species and quantified the reaction of the remaining spe- cies. The experiment is similar to that used by Munger and Brown (1981) and Brown and Munger (1985), who noted that the removal of granivores (Dipodomys) produced an increase in density of granivorous species {Per- ognathus) but produced no increase in den- sity of nongranivorous species {Onychomys and Neotoma : Cricetidae). We were able to make this comparison within the Heteromyi- dae by taking advantage of the evolutionary shift in diet of D. microps. Perognathtis and Dipodomys typically have similar diets of seeds and insects. Dipodomys microps is an exception to this dietary rule because it is folivorous and has little dietary overlap with the granivorous P. longimemhris and D. mer- riami (Kenagy 1972). Dipodomys microps should not have to adjust its use of microhabi- tats to avoid competition with P. Iongi7nem- hris and D. merriami. Likewise, these seed- eating heteromyids would not be subject to the same competitive pressure to forage in different microhabitats when coexisting with D. microps as they would when coexisting with more conventional granivorous het- eromyids. A study of the reaction of rodents to D. microps is the analog in evolutionary time of the removal of species in ecological time. In both cases the idea is to determine how the community responds when a species is re- moved, either by the removal of a species in ecological time or by the shift of a species to a new and nonoverlapping diet in evolutionary time. Materials and Methods The study area is located near Goldfield, Nevada, at an elevation of 1,530 m in the Tonopah section of the Great Basin Desert (Gronquist et al. 1972). Rainfall averages 11.5 cm per year. Vegetation is dominated by shadscale (Atriplex confertifolia). Other com- mon shrubs include A. canescens, Sarcobatus vermiculatiis , Kochia americana, and Lycium cooperi. As is typical of this area, the cover of forbs and grasses is low. The entire area is grazed by cattle and wild horses. During the summers of 1980 and 1981 trap- ping grids were established at the study site. We used 10 grids in the first year and 13 grids in the second year. Each grid was a 210-m square (4.4 ha) with trap stations at 15-m in- tervals, for a total of 225 trap stations per grid. Sherman live traps (7.5 x 23 cm), baited with mixed bird seed, were used. The grids were trapped from June 6 to August 18 in 1980 and from June 2 to July 8 in 1981. This produced a total of 36,000 trap-nights. The grids were divided into controls and treatment plots. On the two control grids there were no removals, but the controls were trapped at the same interval as the other grids. There were four experimental treat- ments: removal of D. microps, removal of D. merriami, removal of both species of Dipodomys, and the removal of F. longimem- bris. All of these treatments were replicated twice the first summer and at least twice the second summer. All grids were initially censused with two nights of trapping, and estimates of the initial number of animals on the grids were obtained using the Jolly method (White 1971). Each animal captured was identified, sexed, weighed, and given a unique eartag (monel fingerling tag). We immediately released the rodents on the control grids. Animals to be removed were turned loose about eight km away; no animal that had been removed from a grid ever returned. At approximately seven- day intervals we trapped each grid to maintain the removals. The use of habitats was quantified by plac- ing each trap in a specific microhabitat. The three microhabitats used were bush, near a bush (0.33 m of bush), or in the open (greater than 0.33 m of bush, but placed to maximize the distance to the nearest bush). The traps, when being set, were alternated among the microhabitats in a regular pattern. This meant that 75 traps were placed in each of the three microhabitats. January 1987 Lemen, Freeman: Heteromyid Ecology Table 1. The number of captures of rodents in each microhahitat in situations with no removals. Chi" vahies are from a goodness-of-fit test comparing the actual use of the open and bush microhabitats by each rodent to equal use of both microhabitats. Microhabitats Bush Near Open Chi' P. longimembris year 1 year 2 235 (.56) 197 (.54) 213 161 187 (.44) 170 (.46) 5.46* 1.99 D. merriarni year 1 year 2 260 (.47) 115 (.44) 258 123 295 (.53) 148 (.56) 2.21 4.14* D. microps year 1 year 2 90 (.49) 78 (.42) 104 95 93 (.51) 109 (.58) 0.05 5,14* T.\BLE 2. The number of captures of rodents in each microhahitat in situations of intraspecific removals. Chi' values are from a contingency test comparing the use of the bush and open microhabitats by species with and without intraspecific removals. Microhabitats Bush Near Open Chi- P. longimembris year 1 123 118 98 0.00 year 2 49 37 27 2.97 D. merriami year 1 68 93 81 0.07 year 2 18 14 17 0.74 D. microps year 1 14 20 22 1.28 year 2 16 16 16 0.77 Table 3. The number of captures of rodents in each microhahitat in situations with interspecific removals. Chi^ values are from a contingency test comparing the use of the bush and open microhabitats by species with and without interspecific removals. Microhabitats Bush Near Open Chi^ P. longimembris year 1 -D. mcr 129 130 149 5.79* -D. mic 116 109 94 0.01 year 2 -D. mer 32 32 39 1.77 -D. mic 20 15 20 0.20 D. merriami yearl -P. long 93 100 95 0.49 -D. mic 45 54 47 0.18 year 2 -P. long 12 24 25 1.69 -D. mic 21 19 34 0.57 D. microps yearl -P. long 116 91 94 1.44 -D. mer 45 54 47 0.00 year 2 -P. long 14 29 29 1.22 -D. mer 27 18 25 1.72 Results Analysis of the preferences in microhahitat was performed on the 5,821 captures of three species (Tables 1, 2, 3). We used the capture data from control grids and the initial census data to estimate microhahitat preferences. These preferences were used to test the hy- pothesis that the rodents foraged equally in all microhabitats. Although we report use of the near microhahitat, we used only open and bush, the two extreme microhabitats, for the statistical tests. In 1980 P. longimeinbris was the only species that deviated from random Great Basin Naturalist Vol. 47, No. 1 Table 4. Spatial patterns of distribution for the three most common heteroin\ids on control grids dining summer of 1980 (because of the small number of P. lon^imembris on control grid #.3, two other grids where this species was more abundant are substituted). Chi" values are generated by comparing the actual nearest neighbor distance to those expected by a random pattern of distribution. In all cases where a significant deviation from random occurs it is caused by hyperdispersion and not by clumping. Intraspecific grid n Chi^ df P p. longimembris 7 40 10.01 2 < 0.01 9 35 8.52 2 < 0.025 10 28 7.32 2 <0.05 D. meniami 3 20 2.91 2 >0.1 10 53 5.97 2 <0.06 female 10 28 13.5 2 <0.005 male 10 21 11.6 2 < 0.005 D. microps 3 13 39.83 2 < 0.005 10 12 22.3 2 < 0.005 Interspecific merr. -microps 3 20 0.53 2 >0.1 10 53 1.23 2 >0.1 microps-long. 3 13 2.05 2 >0.1 10 12 1.85 2 >0.1 merri.-long. 3 20 5.86 2 <0,06 10 53 12.22 2 < 0.005 use of all microhabitats (Chi" = 5.46, p < 0.05). In 1981 D. merriami and D. microps deviated significantly from equal use of all habitats (Chi' = 4.14, p < 0.05, and Chi' = 5.40, p < 0.05 respectively), with both spe- cies of Dipodomys favoring the open micro- habitat. In 1981 P. longimembris did not devi- ate significantly from equal use of all microhabitats, but, consistent with the 1980 data set, it was caught most often in the bush microhabitat. Chi" contingency tables were used to com- pare the preferences of species for microhabi- tats with and without species removals (Tables 2, 3). Intraspecifically, removal of a species produced no significant shifts in the use of microhabitats. Interspecifically, P. longimem- hris had a significant reaction to the removal of D. merriami (in 1980 Chi' = 5.79, p < 0.05, in 1981 Chi' = 1.77, p > 0. 10, combined Chi' = 7.21, p < 0.01). In both years the use of microhabitats by P. longimembris shifted to- ward the open when D. inerriami was re- moved. Removal of D. microps did not pro- duce a significant shift in the use of microhabitat by P. longimembris. Neither D. merriami nor D. microps showed a shift in microhabitat use in response to the removal of any species. Detailed information on the esti- mated number of animals on grids can be found in Lemen and Freeman (1986). We calculated that the effect of trap compe- tition on the relative availability of traps was small (less than 1%) because the three het- eromyids all used the microhabitats in about equal proportions and because we had only moderate trap success (normally 15-20%). As for the spatial relationships of these ro- dents, we calculated a center of activity for all individuals on the control grids about three weeks after the initial census. Using this cen- ter of activity, we found both intra- and inter- specific distances to nearest neighbor. These distances were compared to the expected dis- tributions of distances if we assume a random distribution of the centers of activity (Pielou 1974). The results are shown in Table 4. Both P. longimembris and D. microps were hyper- dispersed intraspecifically. Dipodomys merri- ami was almost significantly hyperdispersed on grid 10 with p = 0.06. Interspecifically, P. longimembris and D. merriami were the only species that were hyperdispersed. Our analysis of fecal pellets confirms that there are two types of diets in the three het- eromyids under study at this site (Lemen and Freeman 1986). Dipodomys merriami and P. longimembris eat a wide varietv of materials January 1987 Lemen, Freeman: HeteromyidEcolocy including vegetation, seeds, and insects, while D. microps concentrates on leaf mate- rial. Discussion We expected D. merhami to prefer the open microhabitat and P. longimembhs to prefer the bush microhabitat (Rosenzvveig and Winakur 1969, Lemen and Rosenzweig 1978, Brown 1975). Based on these expectations, we predicted that removal of D. mcrriami would cause P. longimemhris to increase its use of the open microhabitat. Dipodomys merhami, however, showed only a slight preference for the open, a preference not statistically signifi- cant in 1980. This seems to invalidate the basis for the prediction of a shift in foraging by P. longimembhs. In spite of this, whenD. merh- ami was removed, P. longimemhris shifted its use to the open microhabitat as originally pre- dicted. One explanation for the shift by P. longimemhris is that D. merriami is detecting and forcing the smaller animals out of the open areas more eflPectively than from the bushes. Removal of P. longimemhris had no effect on the foraging of D. merriami. Dipodomys merriami does have a high over- lap in diet with P. longimemhris, and both Price (1978) and Wondolleck (1978) found shifts in the use of microhabitats by D. merri- ami in response to short-term removals oiPer- ognathus. Our results, although differing from those of Price (1978) and Wondolleck (1978), are consistent with the idea that the behaviorally dominant species will not adjust its foraging behavior with the short-term re- moval of subordinate species. Over a longer period of time, as seed densities in microhabi- tats change, D. merriami might alter its selec- tion of microhabitats. The long-term study to demonstrate the effect of removing a small heteromyid on the density or foraging behav- ior of a larger species has not been done. Long-term studies by Munger and Brown (1981) have documented the effects of remov- ing large species on the remaining smaller species. The reaction of the other rodents to re- moval of D. microps is a measure of the impor- tance of competition for food in these species. If food is competed for, then the folivorous D. microps should not compete strongly with the granivorous D. merria7ni or P. longimem^hris. Removal of D. microps should have no effect on microhabitat preferences of D. merriami and P. longimemhris. This prediction is con- firmed by our data. Further, the removal of D. merriami or P. longimemhris should have no effect on the habitat preference of D. mi- crops. This prediction is also confirmed. Presence of D. microps allows one more comparison. Dipodomys merriami and D. mi- crops share many morphological characteris- tics but differ in diet and, by inference, in competition with Perognathus. The evolu- tionary response of D. merriami to avoid com- petition with P. longimeinhhs would not be expected in D. microps. Our data indicate that D. merriami and D. microps have similar patterns of microhabitat use. Therefore, we have no evidence that foraging behavior of D. merriami has been modified by competition with the other seed-eating rodents. If the rodents in this community are com- peting and spacing themselves for minimum overlap, we would expect a hyperdispersion pattern of nearest neighbor distances (O'Farrell 1980, Schroder and Geluso 1975). Intraspecifically, both P. longimemhris and D. microps were hyperdispersed (Table 4). Dipodomys merriami did not show a statisti- cally significant pattern of hyperdispersion, but it very nearly did. Interspecifically, P. longiinemhris and D. merriami are hyperdis- persed, but D. microps is randomly dis- tributed with respect to both. These results are consistent with the hypothesis that these rodents are using members of their own spe- cies and sometimes members of other species (if there is high overlap in diet) as cues for spatial distribution. In summary, we have strong evidence that both food and microhabitats are competed for by these heteromyids. We infer the impor- tance of microhabitats based on the reaction of P. longimemhris to the removal of D. merri- ami. We infer the importance of food based on the lack of response when D. microps is re- moved and based on the pattern of hyperdis- persion found between granivores but not be- tween granivores and foliovores. We also have evidence that interference competition, based on a dominance hierarchy, is present. We infer the importance of interference com- petition based on both the short-term reaction of P. longimemhris to the removal of D. merri- ami and the failure of D. merriami to respond 6 Great Basin Naturalist Vol. 47, No. 1 to the removal of F. longimembris. Change in foraging behavior by P. longime7nbris in response to the removal of D. merriami is only 8%. This small change is consistent with the small increase in numbers of P. longbnembris when D. merriaini is re- moved (Lemen and Freeman 1986). We found that approximately 13 D. Dierriami have to be removed to expect an increase of 1 P. longimembris. We conclude that short- term perturbations do produce evidence of competition for food and microhabitats, but these interactions are weak. It may be that long-term removals, with enough time pass- ing to affect food resources on grids, would show stronger interactions (as found by Munger and Brown 1981 and Brown and Munger 1985), or that short-term perturba- tions are more important in other years or places (as found in Lemen and Freeman 1983), or that competitive interactions are simply weak in this community. More work will have to be done to resolve this problem. Acknowledgments We thank the Field Museum of Natural History, Chicago, for the initial support for this project; the University of Nebraska-Lin- coln for support in the second year; the Ne- vada Department of Wildlife and the Bureau of Land Management for their cooperation; M. Clausen and J. Krupa for their tireless assistance in the field; and Robin Noonan for typing the manuscript. Literature Cited Blaustein, a. R.. and A. C Risser. 1974. Dominance relationships of the dark kangaroo mouse (Mi- crodipodomys rnegacephahis) and the little pocket mouse {Perognathus longimembris) in captivity. Great Basin Nat. 34: 312-316. 1976. Interspecific interactions between three sympatric species of kangaroo rats (Dipodomys). Anim. Behav. 34: 381-385. Brown, J H. 1975. Geographical ecology of desert ro- dents. Pages 315-,341 in M. L. Cody and J. M. Diamond, eds. , Ecology and evolution of commu- nities. Belknap Press, Cambridge, Mass. Brown. J H . and J C Munger 1985. Experimental manipulation of a desert rodent community: food addition and species removal. Ecology 66: 1545-1563. Congdon, J 1974. Effects of habitat quality on distribu- tion of three svmpatric species of desert rodents. J. Mammal. 55: 6.59-662. Cronquist. a., a. H Holmgren, and J. L Reveal 1972. Intermountain flora: vascular plants of the Inter- mountain West. Vol. 1. Hafner Publishing Com- pany, Inc., New York, N.Y. ElSENBERG, J F 1963. The behavior of heteromyid rodents. University California Publ. Zool. 69: 1-100. Frye, R. J 1983. Experimental field evidence of inter- specific aggression between two species of kanga- roo rat {Dipodomys). Oecologia .59: 74-78. Kenagy, G J 1972. Adaptations for leaf eating in the Great Basin Kangaroo rat, Dipodomys microps. Oecologia (Berl.) 12: 383-412. Lemen, C. A, and P VV Freeman 1983. Quantification of competition among coexisting heteromyids in the Southwest. Southw. Nat. 28: 41-46. 1986. Interference competition in a heteromyid comnumitv in the Great Basin of Nevada, USA. Oikos 46: 390-396. Lemen, C. A., and M L Rosenzweig 1978. Microhabitat selection in two species of heteromyid rodents. Oecologia 33: 127-135. Munger, J C , and J H Brown. 1981. Competition in desert rodents: an experiment with semiperme- able exclosures. Science 211: 510-512. OFarrell, M J 1980. Spatial relationships of rodents in a sagebrush community. J. Mammal. 61:589-605. PlELOU, E. C 1974. Population and community ecology: principles and methods. Gordon and Breach Sci- ence Publishers. 424 pp. Price, M V. 1978. The role of microhabitat in structuring desert rodent communities. Ecology 59: 910-921. Rosenzweig, M. L. 1973. Habitat selection experiments with a pair of coexisting heteromyid rodent spe- cies. Ecology 54: 111-117. Rosenzweig, M. L., and J Winakur. 1969. Population ecology of desert rodent communities: habitats and environmental complexity. Ecology 50: 558-572. Schroder, G. D , and K. N. Geluso 1975. Spatial distri- bution of Dipof/o/n(/.sspecfa/7i/is mounds. J. Mam- mal. .56: 363-367. White, E G 1971. A versatile Fortran computer pro- gram for the capture-recapture stochastic model of G. M. Jolly. J. Fish. Res. Bd. Canada 28: 443-445. Wondolleck, J. T 1978. Forage-area separation and overlap in heteromyid rodents. J. Mammal. 59: 510-518. SEQUENCE OF EPIPHYSEAL FUSION IN THE ROCKY MOUNTAIN BIGHORN SHEEP Danny N. Walker' Abstract. — Sequence and timing of epiphyseal fusion of the postcranial skeleton of Rocky Mountain bighorn sheep (Ovis canadensis canadensis) was examined. Ages up to four years can he determined. Slight differences were found in the time of fusion between males and females. These do not prevent determining the age of a skeleton within a period of two or three months, an accuracy comparable to existing technicjues that involve tooth eruption schedules, horn annulations, or incisor cemental annulations. Several techniques have been developed or proposed on skull or mandible characteristics to determine ages of bighorn sheep (Ovis canadensis canadensis). These include tooth eruption schedules (Cowan 1940, Deming 1952, Hemming 1969), cemental annuli ac- cretion rates (Hemming 1969, Turner 1977), horn annulation counts (Cowan 1940, Murie 1944, Tavlor 1960, Welles and Welles 1961, Geist 1966, Hemming 1969, Turner 1977), and body weight or other physiologic features (Klein 1964, Hansen 1965, Blood et al. 1970). Taylor (1960) presents a small amount of data on epiphyseal fusion of three selected long bones and the vertebral column. Without skulls or mandibles, only general size differ- ence patterns in skeletal development (an in- accurate method because of the sexual dimor- phism seen in adults of this species) can be used to establish age of postcranial skeletal remains of bighorn sheep. A technique also used to age animals uti- lizes the sequence of epiphyseal fusion of the postcranial skeleton. This sequence has been documented for Bison bison (Duftield 1973), Odocoileiis hemionus (Lewall and Cowan 1963), O. virginianus (Purdue 1983), Cervus elaphtis (Knight 1966), Ursus americanus (Marks and Erickson 1966). Limited data are available for other mammalian species (Todd and Todd 1938, Madsen 1967). The sequence of fusion with advancing age has been well established for most domestic animals, in- cluding sheep (Getty 1975). However, except for Taylor's (1960) brief mention, there has not been a complete fusion sequence established as an aging technique for the postcranial skeleton of bighorn sheep similar to those es- tablished for other taxa. The present study was undertaken to provide this information on the Rocky Mountain bighorn sheep. Materials and Methods Skeletons of 1 fetus, 6 neonates of unknown sex, and 44 older animals (23 females and 21 males, Table 1) were examined. Yearly age classes of these animals were established from tooth eruption schedules (Hemming 1969, Deming 1952). A median birth period of the first week in June was assumed (Thorne et al. 1979, Turner 1977). Month or week of death was determined from mortality data furnished by the Colorado Division of Wildlife or the Wyoming Game and Fish Department. Dif- ferences between the two dates provided monthly age classes within the yearly age classes. Except for neonates and the fetus, most specimens used in the study either died in the wild or were live-trapped animals that died in captivity within one year of capture. The remaining animals were in captivity up to three years before their death. Given this source of specimens, any potential bias or early fusion that might have resulted from probably improved nutrition and related body changes of animals pen-reared from birth was greatly reduced. Because all sheep in this study were born in the wild, no actual age of any specimen is known. However, by combining the informa- tion provided by the eruption schedules and office of the Wyoming State Archaeologist, Department of .Anthropology , and Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming 82071. Great Basin Naturalist Vol. 47, No. 1 Table 1. Rocky Mountain liighorn sheep specimens examined. Catalog nmnher' Sex Age UWA-8272B unknown UWA-8345B unknown UWA-8346B unknown UWA-8347B unknown UWA-8348B unknown UWA-8349B unknown UWA-8350B unknown UWA-8214B unknown UWA-8621B female UWA-8270B female UWA-8.353B female UWA-8.359B male UWA-8358B male UWA-8623B female UWA-8619B female UWA-8622B male UWA-8211B male UWZ-.5394 male UWA-8429B male UWA-8430B male UWA-8431B male UWA-8432B female UWA-8433B female UWA-8230B male UWA-8231B male UWA-8354B female UWA-8398B female UWZ-5395 male UWA-83'55B female UWA-8357B male UWA-8248B female UWA-8252B female UWA-8269B female UWA-8397B male UWA-8290B male UWA-8.565B male UWA-8435B male UWA-8356B female UWA-8249B female UWA-8333B female UWA-8253B female UWA-8360B female UWA-8415B male UWA-8410B male UWA-8.396B female UWA-8204B female UWA-8210B male UWA-8197B male UWA-B0340 male UWA-8544B female UWA-8309B female 5-month fetus newborn newborn newborn newborn newborn newborn one week less than 4 months less than 4 months greater than 4 months 4 months 4.. 5 months 7.5 months 7.5 months 7.5 months 7.5 to 8 months 7.5 to 8 months 8 months 8 months 8 months 8 months 8 months 9 months 9 months 1 year, 4 months 1 year, 5 months 1 year, 5 months 2 years, 2.5 months 2 years, 3 months 2 years, 3.5 months 2 years, 4 months 2 years, 5 months 2 years, 5 months 2 years, 6 months 2 years, 7 months 2 years, 8 months 3 years, 3 months 3 years, 4 months 3 years, 4 months 3 years, 4 months 3 years, 4 months 3 years, 4 months 3 years, 4 months 3 years, 5 months 3 years, 6 months 3 years, 6 months 3 years, 6 months 3 years, 6 months 3 years, 6 months 3 years, 8 months ''UWA = Univeristy of Wyoming. Anthropology Collections UWZ = University of Wyoming, Zoology Museum Collections the months of death, I feel ages of the speci- mens as presented here were adequate for the present purpose. Regional variation was mini- mized by examination of specimens from the Colorado Front Range and foin- Wyoming mountain ranges (Medicine Bow Mountains, Big Horn Mountains, Wind River Mountains, and Absaroka Range). Osteological nomencla- ture and terminology follow Getty (1975). All bones of each skeleton were examined. The degree of ossification at each location where an epiphysis and a diaphysis occur was recorded. Only those locations where ossifica- tion has occurred are discussed in the individ- ual age classes below. If a location is not dis- cussed, it has already fused and therefore is discussed in a young age class, or it fuses at a later time and is discussed in an older age class. Four degrees of ossification were used and are defined as follows: Stage i: Unfused. Epiphysis is completely separate from diaphysis with no ossification between the two por- tions of bone. Stage 2: Beginning to fuse. Ossification has started between epiphysis and diaphysis, but surface of the epi- physeal groove is open. Stage 3: Fused but epiphyseal line is visible. Diaphysis and epiphysis are completely joined, but fusion line can still be seen. Stac;e 4: Completely fused. Line of epiphyseal fusion is no longer visible. Fusion Sequence Five-month fetus (N = 1): All bones are at fusion stage 1. Neonates (N = 6): Central and fourth tarsals are at stage 2, forming the centroquartel bone. Distal pubis and ischium are at stage 4, but proximal ends of these bones are still at stage 1 . Left and right halves of thoracic neu- ral arches are at stage 3. One week (N = 1): Centroquartel fusion is now at stage 3. Left and right halves of tho- racic neural arches have advanced to stage 4. Cervical, lumbar, and sacral neural arches are at stage 3, except for the odontoid process of the axis (second cervical) which is still at stage L Four month, both sexes (N = 4): All ele- ments of carpus are at fusion stage 4. All tarsus elements except for centroquartel and cal- caneal tuber are also at stage 4. Centroquartel is at stage 3 and calcaneal tuber is at stage L Centra and neural arches of all vertebrae are now at stage 3. Rib tubercles are at stage 4 fused with ribs. Proximal epiphyses of both metacarpal and metatarsal are at stage 4. Prox- imal epiphysis of radius is at stage 3. Four month, male (N = 1): Lateral halves of January 1987 Walker: Bighorn Sheep atlas (first cervical) are at stage 4 on ventral side and stage 1 on dorsal side. Odontoid pro- cess of axis is at stage 3. Distal humerus epiph- ysis is stage 2. The two distal epiphyses of the metatarsal and metacarpal are fused with each other (stage 4) but at stage 1 with diaphyses. Four and one-half month, male (N ^ 1): Distal humerus and proximal radius are at stage 4. Fusion between the illium, pubis, and ischium is at stage 4. Supraglenoid tuber- cle (Tuber scapula) is at stage 4. Seven and one-half to nine month, male (N = 8): All epiphyses at stage 3 at four months are now at stage 4. Seven and one-half to eight month, female (N = 4): Proximal epiphysis of second pha- lange is at stage 4. Centroquartel is still at stage 3. Fusion on dorsal atlas is at stage 3. Odontoid process of axis is stage 4 with the rest of the atlas. Illium is stage 3 with pubis and ischium at the acetabulum. Supraglenoid tubercle is stage 4, as is proximal radius. Dis- tal epiphyses of metacarpals and metatarsals are in stage 4 with each other, but still at stage 1 with diaphyses. One year, five month, male (N = 1): Fusion sequence on all bones available is the same as seven-and-one-half-month males. Overall size increased during the year's growth. This specimen was lacking the lower extremities, and so the fusion stage of phalanges is un- known. One year, four to five month, female (N = 2): Proximal end of first phalange is at stage 4. Fusion of the three innominate elements is also at stage 4. Two year, two and one-half month, female (N = 1): Distal tibia is at stage 2. Second, third, and fourth sacral vertebrae are at stage 2 on their lateral processes, but sacral epiphy- ses are still at stage 1. Minor trochanter of femur is at stage 1. Two year, three month, male (N = 1): Prox- imal end of first phalange is at stage 3. Second, third, and fourth sacral vertebrae are at stage 2 on their lateral processes, but sacral epiphy- ses are still at stage 1. Two year, three and one-half month, fe- male (N = 1): All sacral vertebrae are now at stage 4 on lateral processes. Distal tibia, distal metacarpal, and minor trochanter of femur are all at stage 4. Two year, four to five month, female (N = 2): Anterior epiphysis of first sacral vertebra is now at stage 4 with the vertebra. Other epi- physes on the sacrum are at stage 3. Rib heads are now at stage 2. Distal femur and distal metatarsal are at stage 4. Proximal epiphysis of femur and calcaneal tuber are at stage 3. Two year, five to eight month, male (N = 4): Distal tibia is at stage 2. Humerus head and major tuberosity are at stage 3 with each other, but at stage 1 with the diaphysis. Fe- mur head is at stage 4 with greater trochanter. Neither is fused to the diaphysis. Three year, three month, female (N = 1): Rib heads are at stage 4 with the rest of the rib. Proximal femiu" is still at stage 3. Humerus head and major tuberosity are at stage 3 with each other but at stage 1 with diaphysis. Three year, four month, both sexes (N = 6): Caudal vertebrae epiphyses are at stage 4. All sacral vertebrae epiphyses are at an advanced stage 3. Anterior and posterior epiphyses of seventh lumbar vertebra are at stage 4, as are anterior epiphyses of fifth and sixth lumbar vertebrae. Proximal and distal femur, proxi- mal til:)ia, proximal humerus, ulna olecranon process, distal ulna, distal radius, and cal- caneal tuber are all at stage 4. Three year, five to six month, both sexes (N = 6): Anterior epiphyses of cervical vertebrae three through seven are at stage 2. All lumbar vertebrae epiphyses are at stage 4. Thoracic vertebrae epiphyses are at stage 2 (posterior vertebrae more so than anterior). All long bones are now at stage 4. Three year, eight month, female (N = 1): All postcranial elements of this specimen are at stage 4. The sternebrae have also fused together in this specimen, although other specimens in the collection from older age classes do not have fused sternebrae. This may be irregular in fusion, depending on the individual. Discussion The epiphyseal fusion sequence in the postcranial skeleton of the Rocky Mountain l^ighorn sheep follows the same yearly se- quence in the two sexes. During the first year, however, males are slightly ahead of females when specimens of the same age are com- pared. In succeeding years, fusion in females is slightly ahead of males. This may reflect faster growth rates of males during the first year and quicker maturation of ewes in sue- 10 Great Basin Naturalist Vol. 47, No. 1 Table 2. Summary of known stage 4 fusion times. Rocky Mountain bighorn sheep. M = males. F = females. Neonate One week Four to five month Seven to nine month Element First phalanx (proximal) Second phalanx (proximal) Metacarpal (proximal) Metacarpal (distal) Metacarpal (distal epiphyses) Radius (proximal) Radius (distal) Ulna (proximal) Ulna (distal) Humerus (proximal) Humerus (distal) Humerus (proximal epiphyses) Scapula (supraglenoid process) Metatarsal (proximal) Metatarsal (distal) Metatarsal (distal epiphyses) Tibia (proximal) Tibia (distal) Femur (minor trochanter) Femur (head to greater trochanter) Femur (proximal) Femur (distal) Innominate (distal pubis and ischium) Innominate Cervical vertebrae (epiphyses) Atlas vertebrae (lateral halves) Axis vertebra (odontoid process) Thoracic vertebrae (neural arches) Thoracic vertebrae (epiphyses) Lumbar vertebrae (epiphyses) Sacral vertebrae Sacral vertebrae (anterior epiphyses) Sacral vertebrae (lateral processes) Vertebrae (centra and neural arches) Rib (tubercles) Rib (head) Carpal (all elements) Tarsal (centroquartel) Tarsal (calcaneal tuber) M-F M-F M M M M M-F M M M M-F M-F M-F M-F M M ceeding years (Silberberg and Silberberg 1949). Comparing results of the present study with Taylor's (1960) work shows some incon- sistencies with selected bones. All specimens examined by Taylor were mortalities horn the National Bison Range, Montana. Although this range is fenced, sheep are not restricted to small pens and live as natural a lifestyle as possible (Taylor 1960). Growth of Taylor's ani- mals would not have been biased by intensive pen rearing and its accompanying different nutrition (McEwan 1968). Neither was sheep growth biased in the present study. Conse- quently, results of the two studies should be similar. Taylor (1960, Table XVII) showed the fe- mur is not fused until five years, nine months of age, two and one-half years after the time shown by the present study. Taylor reported the metacarpal to fuse at three years, eight months, which is one and one-half years later than seen here. The thoracic vertebrae fused at four years, nine months, according to Tay- January 1987 Table 2 continued. Walker: Bighorn Sheep 11 One year, five month Two year, three to five month Two year, five to eight month Three year, tliree to six montli Three year, eight month M-F M-F M-F M-F M-F M-F M-F M-F M-F F M M-F M-F M-F M M-F M-F M-F M-F lor. This is one year and two months after that found in this study. Fusion times shown by Taylor for cervical and lumbar vertebrae and humerus agree with the present study. These discrepancies are unexplained. Ex- act ages of several of Taylor's specimens (in- cluding those particular animals apparently causing the above discrepancies) were not known (Taylor 1960). Since this fusion se- quence was first established five years ago, additional specimens not used in the original study have been examined. In all cases, I have been able to age these additional specimens using the fusion sequence to an accuracy com- parable to tooth eruption sequences, or to known ages. Based on the consistency with which 1 have been able to crosscheck this sequence, I feel ages of Taylor's specimens were overestimated. Therefore, the fusions in those skeletons would have appeared to occur later than they did. The present study has demonstrated that the postcranial skeleton of the Rocky Moun- tain bighorn sheep can be used to determine 12 Great Basin Naturalist Vol. 47, No. 1 age. Allowing for minor sexual differences in the fusion rates, an estimated age to within at least two or three months (Table 2) can be provided. Little if any individual variation in the fusion sequence within the age groupings defined in this study was seen. This is at least as accurate as age determination methods based on skull or mandible characteristics. Tooth eruption and replacement schedules can be used to age within four to six months (Cowan 1940, Deming 1952). Cemental annu- lations are accurate to within a year (and even then the date of death is needed) (Turner 1977). Horn segment counts are also accurate only to within one year (Cowan 1940, Geist 1966). Acknowledgments Financial support for this study was pro- vided by the Pope and Young Club. Their support is greatly appreciated. Additional as- sistance was provided by the Department of Anthropology, University of Wyoming, and the Wyoming Recreation Commission. All specimens utilized in the study are deposited in the University of Wyoming, Department of Anthropology or Department of Zoology and Physiology museum research collections. Permission to use these collections for this study was provided by Dr. G. C. Prison (De- partment of Anthropology) and Drs. M. S. Boyce and J. C. Turner (Department of Zool- ogy and Physiology). M. S. Boyce, G. C. Prison, W. G. Hepworth, and L. C. Todd read and commented on earlier drafts of this paper. Literature Cited Blood, D A . D R. Flock, and W D Wishart. 1970. Weights and growth of Rocky Mountain bighorn sheep in western Alberta. Journal of Wildlife Man- agement 34: 451-4.55. Cowan, I. M. 1940. Distribution and variation in the native sheep of North America. American Mid- land Naturalist 24: 505-580. Deming, O V. 1952. Tooth development of the Nelson's bighorn sheep. California Fish and Game 38: 132-139. DuFFiELD, L. F 1973. Aging and sexing the post-cranial skeleton of Bison. Plains Anthropologist 18: 132-139. Geist, V 1966. Validity of horn segment counts in aging bighorn sheep. Journal of Wildlife Management 30: 634-6.35. GEm'. R. 1975. Sisson and Grossman's anatomy of the domestic animal. 5th ed. 2 vols. W. B. Saunders Co., Philadelphia. 2,095pp. Hansen, C G 1965. Growth and development of desert bighorn sheep. Journal of Wildlife Management 29:387-.391. Hemming, J E 1969. Cemental deposition, tooth succes- sion, and horn development as criteria of age in Dall sheep. Journal of Wildlife Management 33: 5.52-.558. Klein, D R 1964, Range-related differences in growth of deer reflected in skeletal ratios. Journal of Mam- malogy 45: 226-235. Knight, R. R 1966. Bone characteristics associated with aging in elk. Journal of Wildlife Management 30: 369-374. Lewall, E. F., and I. M. Cowan. 1963. Age determina- tion in black-tail deer by degree of ossification of the epiphyseal plate in the long bones. Canadian Journal of Zoology 42: 629-636. McEwan, E H 1968, Growth and development of the barren-ground caribou, II. Postnatal growth rates. Canadian Journal of Zoology 46: 1023-1029. Madsen, R M 1967. Age determination of wildlife: a bibliography. U.S. Department of Interior, De- partment Library Bibliography 2. Ill pp. Marks, S. A., and A W Erickson 1966. Age determina- tion in the black bear. Journal of Wildlife Manage- ment 30: .389-410. Murie, A 1944. The wolves of Mount McKinley. Fauna of the national parks of the United States. Fauna Series 5. 238 pp. Purdue, J R 1983. Epiphyseal closure in white-tailed deer. Journal of Wildlife Management 47: 1207-1213. Silberberg, M , and R Silberberg 1949. Some aspects of the role of hormonal and nutritional factors in skeletal growth and development. Growth 13: 3,59-368. Tavlor, R a., Jr. 1960, Characteristics of horn growth in bighorn sheep rams. Unpublished thesis, Mon- tana State University, Missoula. 129 pp. Thorne, T., G Butler, T. "Varcalli, K Becker, and S. Hayden-Wing. 1979, The status, mortality and response to management of the bighorn sheep of Whiskey Mountain, Wyoming Game and Fish Department, Wildlife Technical Report 7. 213 pp. Todd, T W., and A. W. Todd. 1938. The epiphyseal union pattern of the ungulates with a note on Sirenia. American Journal of Anatomy 63: 1-36. Turner, J C. 1977. Cemental annulations as an age crite- rion in North American sheep. Journal of Wildlife Management 41: 212-217. Welles, R. E., and F B. Welles. 1961, The bighorn of Death Valley. Fauna of the national parks of the United States. Fauna Series 6. 242 pp. PARASITES OF MOTTLED SCULPIN, COTTUS BAIRDI GIRARD, FROM FIVE LOCATIONS IN UTAH AND WASATCH COUNTIES, UTAH Richard A. Heckmann', Allen K. Kinihall', and Jeffery A. Short' Abstract. — Between 1983 and 1985, 97 mottled sculpin. Coitus bairdi Girard, were examined from five collection sites in central Utah for parasites. Eight different species of parasites were observed, representing seven genera of Protozoa {Plistophora, Myxidiiim, Mijxobolus, Ichthijophthiriits, Tricliodina, Apiosoma, Eimeria) and one genus of Nematoda (Rhabdochona) . The highest number of parasites was found in sculpin from the Provo River near residential areas, while the lowest number was recorded from Hobble Creek, a nearby pristine area. A complete list of parasites for C. bairdi with literature citations is presented. Each observed parasite is discussed emphasizing pathogenesis to the host. During the past three years (1983-1985) we have examined populations of mottled sculpin, Cottus bairdi, fiom central Utah streams for parasites. Ninety-seven mottled sculpin were examined, representing five col- lection sites found in Utah and Wasatch coun- ties of central Utah. Many studies pertaining to parasites of fishes center on hosts that have major importance to the commercial and sport-fishing industry. Even though nongame fish species represent potential reservoirs for parasites infecting the game fish, few studies have been published on this group. Hoffman (1967) summarized the literature for known species of parasites for the mottled sculpin. Since that date, one article on C. bairdi para- sites has been published (Muzzall and Sweet 1986, Table 2). The objectives of this study were (a) to sur- vey C. bairdi from four localities in central Utah for parasites, (b) to update the current list of organisms utilizing the mottled sculpin as a host, and (c) to correlate parasite load with the sites selected that were based on impact from human populations. Numerous surveys of freshwater fish para- sites have previously been conducted in many parts of the United States. However, none of them include the mottled sculpin as the pri- mary host, although several species of para- sites were reported from Cottus spp. The mottled sculpin has received little at- tention from parasitologists even though it supports many parasitic groups. Its benthic habit, population densities, water chemistry. and stress may also influence the occurrence of many parasites. These factors appear to make the mottled sculpin an ideal model to monitor water pollution. Materials and Methods Ninety-seven sculpin {Cottus bairdi) were collected from five sites in Utah and Wasatch counties, Utah. Of these, 15 were collected below the state fish traps on the Strawberry River in Wasatch Co., 12 were collected in Hobble Creek in Hobble Creek Canyon, Utah Co. , arid 70 were taken during two years from two sites in the Provo River near the Brigham Young University campus in Utah Co. The sculpin were collected using electro- fishing gear and seines. They were then placed in buckets containing aerated river wa- ter and transported to Brigham Young Uni- versity and kept alive in aquaria until exami- nation. All fish were examined within two days after capture. Each fish was examined for gross pathology after which blood samples were taken from peripheral circulation, stained, and examined for blood parasites. A gross ectodermal evalu- ation was followed by gill and fin scrapings that were observed microscopically. Sterile techniques were used on 10 fish to culture kidney macerate on blood agar to determine bacterial infections. The stomach, intestine, liver, gall bladder, and gills were removed and placed with saline in a separate dish for examination at both the gross and microscopic 'Department of Zoology. Brigham Young University, Provo, Utah 84602. 13 14 Great Basin Naturalist Vol. 47, No. 1 Table 1. Summary of parasites observed for the mottled sculpin, Cottus hairdi , during 1981 and 1982 from central Utah. Nature Number Parasites observed Sample location Year of habitat offish examined Pleistophora sp. Myxidium sp. Mijxoholus sp. Provo River: Residential area Farming area 1981 1981 Impacted Impacted (less severe) 27 10 25.9 10.0 0 0 0 0 Provo River: Residential area 1982 Impacted 33 36.4 36.4 15.2 Hobble Creek (Canyon) 1982 Pristine 12 58.3 16.7 25.0 Strawberry River (Canyon) 1982 Pristine 15 0.0 13.3 26.6 levels. Any abnormal structures in the throat, stomach, liver, kidney, pancreas, and gall bladder were examined at 1,000X magnifica- tion. Methyl green-pyronine Y was incorpo- rated as a vital stain to aid in observing proto- zoan parasites from host fish. Direct fecal smears were obtained from the intestine, and any coccidia found were stored in 2.5% potas- sium dichromate w/v. Nematodes were stored in 70% ethanol until identified. For identifica- tion, nematodes were cleaned and mounted in lactophenol on glass slides. Gill scrapings were stained with Gomori trichrome stain and silver nitrate (5% solution, Klines method). The musculature of the fish was teased apart, and any cysts found were fixed in buffered 3% gluteraldehyde and prepared through stan- dard methods for electron microscopy. Other parasites were fixed in 10% buffered formalin for future reference. Photographs were taken of fresh material and fixed material with light microscopy and electron mi- croscopy techniques. Results and Discussion A list of the parasites recovered during this study and their prevalence in infected fish is given in Table 1. Eight species of parasites were observed in varying rates of frequency from the examined fish. The parasites recovered included both pro- tozoan and helminth examples. Of these, Tri- chodina, Ichthyophthirius , Apiosoma, Eirne- ria, Myxidium, Myxobolus, and Plistophora are common parasites of fish and are consid- ered to have worldwide distributions (Kudo 1966, Hoffman 1967). The life cycles of these protozoa are direct; therefore, increased host density generally leads to an increased preva- lence of the parasite. Although no formal host population estimates were made during the two years of the study, the host density seems to be high in one area of the Provo River where 17 sculpins were captured in two five- foot sweeps of the seine. This high density may account for the high prevalence of para- sites in the residential area of Provo. The pathogenicity of the observed parasitic proto- zoa varies from genus to genus and primarily depends on the density of the parasite for each host. All of the parasites recovered have been recorded previously in Cottus bairdi or other Cottus species in America with the exception of the Myxidium sp. of Kline. This genus was described from material taken in one cottid in China (Bykhovskaya 1962). According to Do- giel (1958), Myxidium is endemic to marine sculpin and has been used to study protozoan evolutionary pathways (Reichenback-Kline 1965). Table 2 lists the parasites of C. hairdi in North America with literature citations. The sculpin in all five study areas contained bacteria cysts. Eighty percent of Strawberry River fish had cocci bacteria cysts in viscera and muscle. Ectodermal bacteria cysts oc- curred on 87.9% of the fish in the Provo River and on 25% of the fish in the Hobble Creek population. The bacterial cultures on blood agar made with host kidney tissue were negative. Each parasite will be discussed separately with comments pertaining to host-parasite re- lationship. January 1987 Table 1 continued. HECKMANNETAL.: PARASITES OF FiSH 15 with percent in fection 1 for sample group Number parasites observed Range for Ichthijuphthirius miiltifiliis Trichodina sp. Apioso7na sp. Eimeria duszijnskii Rhabdochona cotti parasite infection (%) 14.8 30.0 0.0 55.5 40.0 40.7 3.7 40.0 62.9 80.0 5 6 14.8-16.9 10.0-80.0 0.9 0.0 45.5 40.0 42.4 7 0.9-45.5 0.0 0.0 0.0 12.0 58.3 4 12.0-58.3 0.0 0.0 0.0 0.0 0.0 2 13.3-26.6 Table 2. Summary of parasite genera currently listed for Cottus bairdi and Cottits sp. with reference to primary literature source (from Hoffman 1967 to current sources). Protozoa Trematoda Cestoda Acanthocephata Nematoda Arthropoda Apiosoma Eimeria Epistylis^ Ichthyophthiriiis Myxidium'" Myxobolus ° Plistophora^ Trichodina ^ Bolbophorus^ Bucephahis^ Crepidostomum ^ Dactylogynis^^^ Diplostomuin^^^' Gyrodactylus^ Neasciis ^ Nezpercella^ Phyllodistomum ^ Prohemistomum ^ Rhipicotyle^ Tetracotyle^ Proteocephahis ' Schistocephahts ^ Triaenophorus^ Acanthocephalus ^ Echinorhynchus^ Leptochynchoides^ Metechinorhynchus '' Neoechinorhynchus ^ Pomphorhynchus ^ Camallanus^^ Contracaectim^ Etonema^ Haplonema ' Rapliidascaris* Rhabdochona^ Ergasihis Reference to citation; \ Amin and Burrows 1977 B. Boyce 1971 C. Conder et al. 1980 D. Dechtiar 1972 E. Heckmann 1980, 198.3 F. Hoffman 1967 G. Heckmann et al. 1986 (this paper) H. Kritsk-y et al. 1977 I. Margolis 1979 J. Schell 1976 K. Schmidt et al. 1974 L. Threlfall and Hanek 1971 Plistophora: Microsporida The small microsporidan Plistophora was observed in C. bairdi from four of the five collection sites. This group of protozoan para- sites is characterized by size. Most mi- crosporidan spores, often contained in cysts, average 2-3 |xm (Fig. 1). The Plistophora cysts were long, eliptical in shape, and ori- ented laterally in the host. The sporonts con- tained an average of 16 spores, which is char- acteristic of this genus (Fig. 2). The Plistophora from C. bairdi were found in musculature and had no affinity toward any specific location in the body of the host. The pathogenicity of the microsporidans can be quite severe due to their histozoic and coelo- zoic nature. Muscle deterioration can be ob- served for infected tissue at the electron mi- croscopy level of magnification (Figs. 3a, 3b). The myofibrils of the skeletal muscle tissue are broken down near the large intracellular cyst masses (Figs. 3a, 3b). The 16 or more spores within the sporont have typical polar filaments and a single nucleus (Figs. 4a, 4b). Plistophora has been reported from sculpins previously (Table 2); however, species desig- nation has not been published to date (Hoff- man 1967). Myxobolus and Mijxidiiim: Myxosporida Myxosporida is the largest protozoan group that infects fish (Kudo 1966). Myxosporidans have a worldwide distribution and are para- sitic in all organs offish. The life cycle begins 16 Great Basin Naturalist Vol. 47, No. 1 Fig. 1. Mature spores (arrow points) of Plistophora from the mottled sculpin, Cottus hairdi. Microsporidans are characterized by their size; for Plistophora the spores average 2-3 fxm in diameter. 1, lOOX. ' vm yy -^ -iL^J-A..^ '>m£^ i*.:r.;^.S.;-.^:r.^^' Fig. 2. Transmission electron microscopic micrograph of a sporont (arrow points) with de\eloping spores (S). For Plistophora each sporont averages 16 developing spores. Note single nucleus (Nu) within developing spore. 13,800X. with the ingestion of the spore.s by the host. In the host intestine polar filaments from the spore shoot out from the polar capsules (Reichenback-Kline 1965). Amoeboid em- bryos (amoebula) emerge and penetrate the intestine and move into organs or muscle tis- sue where the organism multiplies by plasmo- tomy. Plasmotomy stages were present in the cysts that accompanied the Mijxidium spore for the infected gall bladder of mottled Figs. 3a, 3b. Transmission electron microscopic photo- micrograph of a sporont for Plistophora found in the musculature oi Cottus hairdi. Skeletal muscle deteriora- tion is occurring in the host tissue (arrow points). Spore maturity is characterized by the single polar filament (P) forming in the spore. The sporont wall (w) is corrugated and isolated developing spores from host tissue. 13,800X. sculpin. The observed Myxobolus were taken from stomach tissue with the exception of two cysts that were present in the pectoral muscu- lature and a gill arch. The Myxidiuin spores (Figs. 5a, 5b) are fusiform with two polar capsules. The polar filaments were comparatively long. All spores were found in the gall bladder of mottled sculpin from three collection sites. The other myxosporidan, Myxobolus\ was collected from fish taken from three of the five collection sites. It invades stomach tissue, muscle tissue near the pectoral fin, and mus- cle tissue near the gill arches. The spores were ovoid in shape with two prominent polar cap- sules (Figs. 6a, 6b) at the anterior end. The January 1987 HeCKMANN ET AL. : PARASITES OF FiSH 17 4b Figs. 4a, 4b. Mature spores ofPlistophora infecting the musculature of Coftiis hairdi. Note the single nucleus (Nu) for each spore, polar filament (P) wrapped around the inside of the multi-lavered outer membrane (M). 4a, 13,800X; 4b, 28,000X. parasite was histozoic in nature occupying muscle tissue (smooth and striated) of the host. Eimeria: Sporozoa Freshwater coccidians have been described from Europe, Asia, and North America (Mol- nar 1973). The genus Eimeria is characterized by eight sporozoites within an oocyst. Eimeria duszynskii was identified by the presence of crossbanding on the sporozoite end opposite the refractile body (Conder et al. 1980), at 1,000X magnification (Figs. 7a, 7b). This para- site inhabits the epithehum of the intestine Figs. .3a, 51). Micrograph of Mijxidiiim from the gall bladder of Coff(/.s hairdi. A differential stain. Grams stain, was used for Fig. 5a to emphasize the two polar capsules (arrow points) per spore. Fig. 5b is stained with hemo- toxylin and eosin, emphasizing the sporoblast (S) inside the spore. 1,100X. and develops through a life cycle of asexual and sexual phases (Hammond 1973). Schizogony is an asexual phase of the tropho- zoite that encysts in the small intestine. The cyst expels merozoites which differentiate into male and female gametes. In the sexual phase (gametogony) there is a gradual process of invasion into the lining of the intestine (Do- giel 1965). The zygote is passed out in the feces, and, following sporulation, it is taken in by another host. Spores multiply in an asexual phase (sporogony), followed by sporulation in the intestine (Figs. 7a, 7b). The pathogenicity of coccidians in sculpins has not been described, but in other studies Eimeria has been shown to cause mortality in fish (Molnar 1973). The rupture of large num- bers of intestinal cells is the chief pathology due to this parasite, and mortality can be asso- ciated with decreased ability to absorb nutri- ents, blood loss, and other physiologic stresses. The damaged tissue can cause physi- ologic stress and is subject to secondary inva- Vol. 47, No. 1 Figs. 6a, 6b. The second myxosporidan observ ed in this study, Mtjxobolus, was foinid in stomach tissue and in skeletal musculature near the pectoral fin and gill arch. The characteristic spore wall (VV) is visible for this sample. Using Nomarsky interference lighting makes the two po- lar capsules (arrow points) containing polar filaments prominent. I.IOOX. sion by other pathogens. Ehneria was one of the most common para- sites observed during this study. It was present in C. bairdi fiom four of the five col- lection sites. The type species for E. duszijn- skii came from infected fish of the Provo River, one of the sampling sites for this study. Apiosoma, TricJiodina, and IcJithijophtJiirius: Ciliata Apiosoma is a small, staked ciliate that at- taches to gill surfaces (Figs. 8a, 8b). This cili- ate is 35-44 fxm in size and has a characteristic single cone-shaped macronucleus (Hoffman 1970). Apiosoma is characterized by a holdfast (scopula) that attaches to the gill surface. There is no documentation to show that this parasite can cause major fish mortality, but the potential exists to kill its host. When present in large numbers, it could tax the respiratory surfaces of the gill lamellae. It was observed in mottled sculpin from the three Figs. 7a, 7b. Eimeria duszijnshii from the intestine of CottuH bairdi. The figures represent the sporogonous phase. Spores (arrow points) are released in fecal material whereby other fish can become infected. Note the cross- banding (C) of the sporozoite for Fig. 7b. This is charac- teristic for the species. 7a, 430X; 7b, 1,100X. collection sites on the Provo River. Apiosoma numbers fluctuated with seasons, the highest numbers per fish being observed in the spring. Infected gill tissue containing Apio- soma was characterized by a fibrous host cap- sule surrounding the protozoan parasite. There has been only one species described to date infesting fish (Hoffman 1967). In small numbers Apiosoma does not have pathogenicity, but in higher numbers it could create a blockage of the respiratory gill sur- face. Apiosoma was found infesting fish in the same aquatic sites as Eimeria. Trichodimi are ubiquitous ciliated proto- zoan parasites that infest the gill surfaces of fish. The ciliate rarely causes damage to its host. It will rapidly multiply on weakened hosts. It is characterized by three ciliary girdles (aboral) with taxonomically important, radially arranged hooked teeth or denticles (Fig. 9). There are many undescribed species in North American freshwater fishes (Hoff- man 1967). For this study, mottled sculpin January 1987 HeCKMANN ET AL.: PARASITES OF FiSH 19 Figs. 8a, 8b. The stalked ciliate, Apiosoma. which in- fests the gill surface ofCottus bairdi. Note the cilia (arrow points), niacronucleus (Nu), holdfast (h) for host attach- ment, and large size (35-44 |xm in diameter). 8a, 430X; 8b, 1,100X. Nomarsky phase interference microscope lighting was used for this figure. from a single site on the Provo River were infested with Trichodina (Table 1). Trichodina has been associated with mortal- ity where the level of infection is high and abrasion of the gill tissue is too severe for repair. This causes a physiologic stress on the animal, in addition to opening the area for secondary infections. In one instance, Tricho- dina sp. had a significant association with Gy- rodactyhis sp. (Noble 1961). IcJitJujophthirius midtifiliis was recovered in gill material of C. bairdi taken from all three collection sites on the Provo River. This parasite is very common in freshwater fish and has a worldwide distribution. It has also been the cause of major catfish mortality (Hines and Spira 1973), and much research has been con- ducted to manage the disease (Farley and Heckmann 1980). This ciliate is one of the largest protozoan parasites for fish. During the trophozoite phase of its life history it can measure up to 1 mm in size and thus the name "white spot disease. ' It has a characteristic horseshoe-shaped niacronucleus that is visi- Fig. 9. Trichodina. a ciliated protozoan, from infested Cottiis bairdi gills. Kliens silver stain method was used for emphasis of ciliary rows (arrow points) and denticles (d). Both characteristics are used to ta-\onomically de- scribe species o{ Trichodina. 1,100X. ble with limited magnification (Figs. 10a, 10b) (McCallum 1982). Ichthyophthiriiis in high numbers is detrimental since it can cover the gill respiratory surface. Agglomerate and ben- thic life stages are followed by an adult ecto- dermal phase (Farley and Heckmann 1980). In this stage /. midtifiliis can burrow under the epithelium of its host, subjecting the fish to potential secondary infections. The rapid multiplication of Ichthyophthir- iiis is one reason it is so pathogenic (Hoffman 1967). The greatest mortality caused by this parasite was reported for channel catfish (/c- tahirus sp.) (Hines and Spira 1973). Rhahdochona: Nematoda Rhabdochona is the only helminth from sculpin found during this survey. Several spe- cies of fish are parasitized by this genus of nematodes (Yamaguti 1961). Rhabdochona cotti was found in C bairdi at four of the five collection sites. Larval development for Rhabdochona occurs in several species of mayfly nymphs (e.g., Hcxa^cnia) (Gustafson 1941), thus the ready availability of the ne- matode for mottled sculpin. Not much is known concerning the pathogenicity of this parasite. A high percentage of infections by acanthocephalan parasites, another helminth, have been reported from winter collections in other surveys of sculpins (Amin and Burrows 1977), but the reason for the high rate of infec- tion by R. cotti in the winter-spring season in this study is unknown. Adult Rhabdochona inhabit the intestine of fish. Sections were taken of infected intestine 20 Great Basin Naturalist Vol. 47, No. 1 Figs. 10a, 10b. Ichthyophthiriu.s multifiliis that in- fested the gill surface of Cottiis hairdi from the Provo River, Utah. Note the large size of the ciliate, the horse- shoe-shaped macronucleus (Nu) and the cilia (arrow points). 10a, lOOX; 10b, 430X. containing this parasite and stained using a pentachrome stain (Fig. 11). It is suspected that this nematode has httle pathogenicity; but in large numbers the potential for signifi- cant intestinal damage exists. The adult ne- matode has a characteristic buccal capsule with longitudinal ribs terminating anteriorly in pointed teeth (Fig. 11) (Hoffman 1967). This study has complemented the known parasitofauna of Cottus bairdi with the addi- tion of two protozoan species to the current list of 37 parasites (Table 2). There was a paucity of helminth parasites in the examined sculpin which were common for other collec- tion sites (Heckmann 1983). Ecological Comments The greatest density of parasites observed, the highest number of species found, and the total number of parasites per fish came from C. bairdi inhabiting the Provo River near Brigham Young University (Table 1). This Fig. 11. Rhahdochona cotti was the only helminth observed during this study. This nematode was found in the intestine of Cottus bairdi and is characterized by a narrow buccal capsule (b) terminating anteriorly in pointed teeth (t). lOOX. area receives heavy impact from the local hu- man population. In a pristine mountain stream, Hobble Creek, only two species of myxosporidan parasites were observed in 13 and 26% of the examined fish (Table 1). Acknowledgments The authors thank the Utah Fish and Game Department for their cooperation on this study. James Allen and Connie Swenson from the Electron Optics Laboratory, Brigham Young University, extended professional help for the transmission electron microscope part of the studv. January 1987 HeCKMANNETAL.: PARASITES OE FiSH 21 Literature Cited Amin, O. M . andJ M. Burrows 1977. Host and seasonal associations of Echinorhtjnchus sdlmoiii.s (Atan- thocephala: Echinorhvnchidae) in Lake Michigan fishes. J. Fish. Res. Bd. Canada 34: 325-331. BoYCE, N p. 1971. Ezonema hiconiis gen. et sp. n. (Ne- matoda: Seuratidae) from freshwater fishes of Hokkaido, Japan. J. Parasitol. 57: 1175-1179. Bykhowsk.wa, E., .\nd P.wlovsk.ay.'V 1962. Key to para- sites of freshwater fish of the U.S.S.R. Zoological Institute, No. 80. U.S. Dept. oflnteriorand NSF, Washington, D.C. CoNDER, G A , R Y Oberndorfer, and R. a. Heckmann. 1980. Eimeria duszijnskii s\). n. (Protozoa: Eimeri- dae), a parasite of the mottled sculpin. Coitus bc2irdi Gimrd. J. Parasitol. 66: 828-829. Dechtiar, a. O 1972. Parasites offish from Lake of the Woods, Ontario. J. Fish. Res. Bd. Canada 29: 275-283. DoGiEL, V A. 1958. Parasitology of fishes. Leningrad University Press. Farley, D. C, and R A Heckmann 1980. Attempts to control Ichthijophthimus mtiltifiliis FoiK}net (Cil- iophora: Ophryoglenidae) hy chemotherapy and electrotherapy. J. Fish Diseases 3: 203-212. GusTAFSON, P V 1939. Life cycle studies on Spinitectus gracilis and Rhabdochona sp. (Nematoda; The- laziidae). J. Parasitol. 25(6): 12-13. Hammond. D. M 1972. The coccidia, Eirneria, Isospora, Toxoplasma and related genera. University Park Press, Baltimore, Maryland. 428 pp. Heckmann, R. A 1980. Parasites of fishes in Utah, meth- ods of examination and examples. Proceedings Bonneville Chap. Amer. Fish. Soc. Annual Meet- ing, 1980:110-135. 1983. Eye fluke disease, Diplostomatosis, offishes from the upper Salmon River, Idaho. Proceedings Bonneville Chap. Amer. Fish. Soc. Annual Meet- ing, 1983: 174-179. HiNES.R. S.andD T. Spira 1973. Ichthyophthimus mtd- tifiliis Fouquet in the carp, Cyprinus carpio L. 1. course of infection. J. Fish Biol. 5: 385-392. Hoffman, G. L. 1967. Parasites of North American fresh- water fishes. University of California Press, Berkeley. 486 pp. Kritsky. D C . R. J Ka^ton, and P. D. Leiby 1977. Dactylogijnts ungiiifonnis sp. n. (Monogenea) from the mottled sculpin, Cottiis hairdi Girard, in Idaho, with some taxonomic considerations in the genus Dactylogyrus. J. Helminthol. Soc. Wash- ington 44: 141-147. Kudo. R. R 1966. Protozoology. 5th ed. Charles C. Thomas Publisher, Springfield, Illinois. 1,174 pp. Margolis. L . AND J R. Arthur. 1979. Synopsis of the parasites of fishes of Canada. Fish. Res. Bd. of Canada, Bulletin 199. Markiw, M. a., AND K. Wolf. 1974. Myxosoma cere- bralis: Comparative sensitivity of spore detection methods. J. Fish. Res. Bd. Canada 31(10): 1597- 1600. McCallum, H I 1982. Infection dynamics oilchthyoph- thirius multifiliis. Parasitology 85: 475-488. Molnar, K , AND C H Fernado 1974. Some new £jmc- ria (Protozoa, Coccidia) from freshwater fishes in Ontario, Canada. Canadian J. Zool. 52: 413-419. Muzzall, P M . and R D Sweet 1986. Parasites of mot- tled sculpins, Cottus bairdi, from the Au Sable River, Crawford County, Wisconsin. Proc. Helminthol. Soc. Washington 53: 142-143. Noble, E R 1961. The relations between Trichodina and Metazoan parasites on gills of a fish. Progress in Protozoology, Proceed. 1st Internat. Conf Proto- zool., Prague. Reichenback-Kline. and E Elkan 1965. Book 1. Dis- eases offishes. Academic Press, Inc., Ltd., Lon- don. SCHELL. S C 1976. The life history oiNezpercella lewisi Schell 1974 (Trematods: Opecoelidae), a parasite of the northern squawfish, and the smallmouth bass. J. Parasitol. 62: 894-898. Schmidt. G D . H D Walley, and D S. Wijek. 1974. Unusual pathology in a fish due to the Acanthocephalan Acanthocephalus jacksoni Bul- lock, 1962. J. Parasitol. 60: 730-731. Threlfall, W . and G Hanek 1971. Helminth para- sites, excluding Monogenea from some Labrador fishes. J. Parasitol. 57: 684-685. Yamagutl S. 1961. Systema Helminthum Vol. III. Ne- matodes. Interscience Publishers, Inc., New York. 1,261 pp. EFFECTS OF ARTIFICIAL SHADING ON DISTRIBUTION AND ABUNDANCE OF JUVENILE CHINOOK SALMON (ONCORHYNCHUS TSHAWYTSCHA) William R. MeehaiV, Merlyn A. Brusveir, and John F. Warcl^ Abstract —The influence of artificial shade on the distribution and abundance of juvenile chinook salmon was studied m a side channel of the South Fork Salmon River, Idaho. Fish biomass and abundance were greater in shaded than m unshaded areas when compared to both cumulative incident light reaching the studv sections during the 72-hour test runs and mstantaneous incident light conditions at the end of the 72-hour test runs. Because conditions may be atypical at the tune of instantaneous light measurement, we prefer cumulative incident light for relating light and shade conditions to daytime distribution (abundance and biomass) of juvenile chinook salmon Cover is one of the most important habitat components for anadromous sahnonids dur- ing the freshwater-rearing phase of their Hfe cycle. Cover can be described either as sub- merged cover or overhead cover (Reiser and Bjornn 1979). Examples of submerged cover are rocks and boulders, large organic debris, and aquatic vegetation. Overhead cover in- cludes riparian vegetation, water turbulence, logs and other debris on or close to the water surface, and overhanging or undercut banks. Many of these cover types can also be classed as cover with form; for example, rocks, large organic debris, and undercut banks (Brusven et al. 1986). Riparian vegetation can be classified as either cover with form or cover without form. Cover without form provides shade or insulation against temperature ex- tremes. Shade may be important in maintain- ing cool water; it may also provide protection for fish from predators. Several studies have demonstrated the use of shade by salmonids where the cover is on or below the water surface. In a shallow (24-29 cm) tank, small brook trout (Salvelinus fonti- nalis [Mitchill]) preferred shade as did At- lantic salmon {Salmo salar Linnaeus) parr when they were the only species present; in the presence of trout, salmon parr were gen- erally found in unshaded areas (Gibson and Power 1975). Gibson and Power (1975) found that in a deep tank (43-50 cm) neither species preferred shade. Rainbow trout {Salmo gaird- neri Richardson) fry showed no apparent pref- erence for overhead cover in an artificial tank, but yearlings preferred the covered portion of the tank at all light intensities, except when the yearlings were randomly distributed in total darkness (McCrimmon and Kwain 1966). Juvenile Atlantic salmon were negatively pho- totactic at all but the very lowest light intensi- ties (Pinhorn and Andrews 1963, Gibson and Keenleyside 1966). Gibson and Keenleyside (1966) showed that at all light intensities brook trout in laboratory aquaria generally posi- tioned themselves in the dark areas at edges of shadows created by overhead cover. Butler and Hawthorne (1968) found a direct relation between amount of shade provided by over- head cover and its use by rainbow trout, brown trout {Salvio trutto Linnaeus), and brook trout. Hoar et al. (1957) found that, when given a choice between light and dark areas, schools of chum salmon (Oncorhynchus keta [Walbaum]) or pink salmon (O. gor- biischa [Walbaum]) fry remained in the light, and sockeye salmon (6. nerka [Walbaum]) fry preferred the dark; coho salmon (O. kisiitch [Walbaum]) fry showed no preference be- tween light and dark areas. Sockeye and coho smolts stayed in the dark more than did sock- eye and coho underyearlings. Other studies suggested that cover with form plays a much more important role than does shade. DeVore and White (1978) found no significant diflFerence in response between vs. Department of Agriculture, Forest Service, Pacific Northwest Research Station, Juneau, Alaska 99802. ;jUniversity of Idaho, Department of Plant. Soil, and Entomological Sciences, Moscow. Idaho 8384.3. U.S. Department of Agriculture. Forest Service. Pacific Northwest Research Station, Corvallis, Oregon 97.331, Present address: 3725.5 Crabtree Drive ocio, Oregon y7o/4. ' 22 January 1987 MEEHAN ETAL.: EFFECTS OK SHADING ON SALMON 23 brown trout in different intensities of ineident light due to canopy shading; they found, how- ever, a significant difference in response to physical cover with the highest correlation occurring when the cover was closest to the substrate (provided fish could still get under it). Gibson (1978) observed that shade was attractive to both Atlantic salmon parr and brook trout in shallow water; but given the choice of a shallow (30-cm) tank with shade or a deeper (50-cm) tank with no shade, the ma- jority of both species selected the deeper tank. In this study Gibson noted that a turbu- lent water surface was more attractive to salmon parr than was shade. The studies cited above were conducted for the most part in laboratory tanks or aquaria. In natural stream conditions, Gibson (1966) found that brook trout generally remained un- der overhanging cover, such as alder bushes, except at times of low illumination in early morning and in the evening. He noted that Atlantic salmon parr usually were observed away from such cover; they fed all day in brightly lit open areas of the stream. No signif- icant difference was found between distribu- tions on cloudy and on sunny days for either trout or salmon. When artificial shade was installed along a previously unshaded stream reach, brook trout were attracted to the shaded area (Gibson 1966). In a field study of simulated undercut banks, Brusven et al. (1986) found that 85% of the juvenile chinook salmon (O. tshowijtscha [Walbaum]) biomass occurred in covered sections of a stream chan- nel. Hawkins et al. (1983) reported a positive correlation between abundance of salmonids and abundance of invertebrates in several streams in Oregon and northern California. In general they found an inverse relation be- tween shade and density of invertebrates (hence salmonids). Use of specific types of shade cover by salmonids within study reaches was not studied, however. In a study of temperature selection by young brook trout, Sullivan and Fisher (1954) found that at low light intensities trout re- sponded to temperature without regard to shade, but at high light intensities the trout were not observed in the illuminated part of the laboratory trough— that is, shade was sought in preference to temperature. The puiT30se of our study was to evaluate South Fork Salmon River I I Headgate f|-Upper Fish Trap Upper Transition — Middle Transition Lower Transition Lower Fish Trap Outflow South Fork Salmon River - Fig. 1. Study sections of artificial stream channel. South Fork Salmon River, Idaho. the role of artificial shade on the distribution, abundance, and biomass of juvenile chinook salmon in a flow-regulated channel. Study Area The study was conducted in 1977 and 1978 in an abandoned spawning and rearing chan- nel in the South Fork Salmon River drainage in west central Idaho, about 50 km east of Cascade. The channel was constructed over 20 years ago by cutting across an oxbow in the South Fork Salmon River. Since then, the banks have been stabilized by indigenous veg- etation. The channel is 160 m long and drops 0.58 m over its length. It has an upper channel (110 m long) and a lower pool (50 m long) (Fig. 1). The substrate is primarily sand (< 1.5 mm) and pebbles (1.0-3.0 cm). A steel headgate controls flow into the channel. The lower 48 m of the channel (exclusive of the pool) was used to investigate fish distribution in relation to simulated shade-producing riparian vegeta- tion. 24 Great Basin Naturalist Vol. 47, No. 1 SMi * • Fig. 2. Shade canopy in treatment section. The banks of the channel were trimmed to remove rooted aquatic plants, to minimize shading from riparian grasses, and to create a homogeneous habitat throughout the chan- nel. Lodgepole pine (Pimis contorta Dougl. ex Loud.), Douglas-fir {Pseudotsuga menziesii [Mirb.] Franco), and willows (Salix spp.) are sparsely represented on the o.xbow. During midday, shading from these plants is minimal; during early morning and late afternoon, how- ever, some shading is apparent on the chan- nel. Summer-run chinook salmon spawn near the channel, and juveniles use the channel as a rearing area during most years. Steelhead trout {Salmo gairdneri Richardson), bull trout (Salvelinus confluentus Suckley), mountain whitefish (Prosopium williamsoni Girard), and sculpins {Cottus spp.) are also found in the main river and occasionally in the channel. Fish traps were installed at the upper and lower ends of the study reach to determine fish outmigration. Two test units were created within the study reach; each test unit had a treatment section and a control section. Each section was about 7.6 m long and 2.4 m wide; water depth averaged 35-40 cm. Test units and sections within each test unit were also separated by imbedded sills fitted with re- cessed fish netting. The paired test units were further separated by a 2.8-m transition area to remove the shading effects of a canopy in- stalled over the upstream treatment section. Materials and Methods Solar Radiation.— To test shade as a factor influencing distribution and abundance of fish, two A-frames were constructed of 19-mm I.D. pipe. They were 7.6 m long, 3.1 m wide at the bottom, and 2.5 m high at the center. In 1977 dark green saran screen^'^ (20 meshes per 2.5 cm) was placed over the frames in the two treatment sections to form shading canopies (Fig. 2). The control sections were without artificial shade. Light transmittance through a single layer of the screen was 47% when the saran screen, fabric no. Chicopee Manufactuiing Company, Lumite 500.38-CXJ. ■^he use ol trade, firm, or corporation names in this publication is for the information and convenience of the reader. Such use does not constitute an official endorsement or approval by the U.S. Department of Agriculture or the Forest Service of any product or service to the exclusion of others that mav be suitable. January 1987 Meehan et al. : Effects of Shading on Salmon Table 1. Water temperature (C) measured at end of each test run in 1977 and 1978, SFSR channel. 25 Run Test sect ions' Test date IT 2T IC 2C June 1977 1 2 12.47 14.71 12.41 14.64 . °C 12.48 14.84 12.51 14.79 August 1977 1 13.32 13.26 13.38 13.30 2 13.56 13.60 13.57 13.58 July 1978 3 (shade removed) 1 2 12.41 10.56 12.28 12.44 10.70 12.34 12.43 10.62 12.41 12.43 10.61 12.39 August 1978 1 2 10.00 9.17 9.92 9.19 10.08 9.21 10.11 9.18 3 (shade removed) 10.21 10.22 10.34 10.22 'Sections IT and 2T are shaded e.xcept when otherwise indicated; sections IC and 2C are unshaded. 80r 60 h (A (0 E 40 o ■^ 20 2 0 o 60 c a> if 40 Q. 20 Shade No shade r~l p-jShade '— ' removed TC 1 977 TC 1 978 Fig. 3. Fish biomass in shaded (T) and unshaded (C) test sections of study channel, 1977 and 1978. sun was perpendicular to the material, as de- 80r 60 o 40 JQ E 20 3 C *- 0 o 60 5 40 o w 0- 20 Shade No shade riShade removed TC 1 977 TC 1 978 Fig. 4. Fisli abundance in shaded (T) and unshaded (C) test sections of study channel, 1977 and 1978. light transmittance under semishade among conifers and hardwoods near the channel was 15-55%. Thus, the artificial canopy was simi- suii Wets pel jjcinaiv^Liio.! iw iin- iiiciiv 1 itii, "^ ^^ -- _ ^ , - . termined bv a hand-held solarimeter.' Sun- lar to the sparse natural canopy ot the area. In 1978 darker shade was tested by doublmg the screen and rotating the second layer 45 de- ^Matrix Inc. . Mark VT Sol-a-meter. 26 Great Basin Naturalist Vol. 47, No. 1 Table 2. Cumulative incident light (g cal/cnr) measured during test runs in 1977 and 1978, SFSR channel. Test date Test sections' Run IT 2T IC 2C June 1977 August 1977 Mean^ July 1978 August 1978 Mean^ 3 (shade removed) 3 (shade removed) 221 635 448 484 714 447. 0_ (XT 22,5 343 182 188 1028 234. 5_ (XT: 187 574 433 517 788 427.8 437.4) 196 296 171 205 1007 217.0 225,8) g cal/cm" . . . 509 1532 1006 936 832 995^ (XC 1152 1710 960 1120 1115 1235^ (XC 509 1446 1159 1213 832 1081.8 1038.8) 1114 1694 1084 1209 1210 1275.3 1255.4) ^Sections IT and 2T are shaded except when otherwise indicated; sections IC and 2C are unshaded. Mean for runs with shade in place. Table 3. Incident light (g cal/cnr per min) recorded at time offish capture in 1977 and 1978, SFSR channel Run Test sections' Test date IT 2T IC 2C 1 0.5 0.5 g cal/cnr ' per min .... June 1977 1.0 1.0 2 0.5 0.5 1.0 1 0 August 1977 1 0.4 0.5 0.9 1.0 2 0.1 0.1 0.2 0.2 3 (shade removed) 0.7 0.6 0.8 0.8 Mean 0.38 0.40 0.78 0.80 (XT = = 0 .39) (XC = = 0.79) July 1978 1 0.2 0.3 1.1 1.1 2 0.2 0.3 1.1 1 1 August 1978 1 0.2 0.2 1.0 1.0 2 0.2 0.2 0.5 0.8 3 (shade removed) 0.7 0.7 0.8 0.8 Mean 0.20 0.25 0.93 1.00 (XT = = 0. 23) (XC^ - 0.96) 'Sections IT and 2T 2w are shaded except wh len otherwise indicated; sections IC : and 2C are unshaded. Mean for measurements with shade in place grees over the mesh ahgnment of the earher screen, producing 75% shade — more typical of a dense, natural canopy. Four recording pyranographs^ measured solar radiation along the four treatment and control sections of the channel during the tests. These were mounted at about the cen- ter of each section on 1-m-high stands above the substrate. Incident light intensity in gram calories per square centimeter per minute was read off a pyranograph chart when a test run was completed. The cumulative incident hght during a 72-hour test run, in gram calo- ries per square centimeter, was determined Weather Measure Corporation mechanical pyranograph, model R401-S by reading the incident light off the pyra- nograph chart at 2-hour intervals, multiplying each of these readings by 120 (minutes per interval), and summing the 36 observations. Stream Flow. — Water flow through the ar- tificial channel was maintained at approxi- mately 0.11 mVs (3.9 cfs) during the tests by an adjustable head gate at the upper end of the channel. Water Temperature, — Water tempera- tures were measured and recorded in each test section simultaneously by Feabody Ryan Model G-45 recording thermographs. Fish Populations, — ^Juvenile chinook salmon were captured with a 12-volt direct- current backpack electroshocker and a seine January 1987 MEEHAN ET AL.: EFFECTS OF SHADING ON SALMON 27 CM E o 0) a (0 o 20 r 15 10 ^ .05 (A (/) (0 E o 0 Shade No shade .15r □ shade removed , .03r 5 .015 TC 1 977 TC 1978 Fig. 5. Ratio of fish biomass to cumulative incident light in shaded (T) and unshaded (C) test sections of study channel, 1977 and 1978. from the main South Fork Sahnon River in the immediate vicinity of the artificial channel. All captured fish were mixed together. Before each test run, all fish were removed from the study reach by electrofishing. Test fish were then added to the study reach until the carry- ing capacity was established; the carrying ca- pacity was determined by allowing surplus numbers offish to migrate from the channel. The duration of a test was 72 hours that com- menced and ended between 1030 and 1200. This length of time allowed the fish to accli- mate and select preferred habitat. After 72 hours elapsed, a series of block nets were pulled simultaneously to isolate each of the four test sections. After the block nets were in place, fish were removed from each test section, measured (fork length in mm), and weighed to the 10 CM E u a o .05 O) o E 3 C C (0 o Shade No shade □ Shade removed .02 r ,01 TC 1 977 TC 1978 Fig. 6. Ratio offish abundance to cumulative incident light in shaded (T) and unshaded (C) test sections of study channel, 1977 and 1978. nearest 0.1 g. After processing, all test fish were released into the main South Fork Salmon River below the artificial channel. Schedule of Tests and Data Analysis. — During 1977 and 1978, tests were conducted in late June to early July and again in mid to late August. Two tests were run during each of the two test periods each year. The first test used shade canopies over the treatment sec- 28 Great Basin Naturalist Vol. 47, No. 1 0) a c* E o 0) Q. (0 u 0) \ O) (0 (0 (0 E o (0 200 150 100 50 Shade No shade 150 □ Shade removed 40 20 TC 1 977 TC 1 978 Fig. 7. Ratio offish biomass to incident light in shaded (T) and unshaded (C) test sections of study channel 1977 and 1978. tions. In the second test, shade canopies were removed from the treatment sections to estab- hsh fish distribution in the channel without regard to shade. Results and Discussion 100 c E V. Q. CM E o Q. (0 o (0 50 Shade No shade M- 0 •- o E c c 25 (0 0) 20 15 10 □ Shade removed TC 1 977 TC 1 978 Fig. 8. Ratio offish abundance to incident light in shaded (T) and unshaded (C) test sections of study channel, 1977 and 1978. Because water temperature was essentially the same in each test section (Table 1), choice Fish biomass and abundance were greater in of section by fish can be attributed to shade. shaded than in unshaded areas when the re- January 1987 80r 70 60 O) MEEHANETAL.: EFFECTS OF ShADINC, ON SALMON Y= 47.73-.296X r2=.52 p<.001 n = 40 oTreatment sections • Control sections 29 200 400 600 800 1000 1200 1400 1600 1800 Cumulative incident light (gm cal/cm^) Fig. 9. Relation between cumulative incident light and fish biomass for all test runs, 1977 and 1978 combined. suits of the June-August tests were pooled for 1977 and 1978 (Figs. 3, 4). Differences be- tween years in fish response to shade were evident, particularly when tests of the shade-no shade choice were compared to tests of shade removal. These differences be- tween years are less apparent when fish biomass and abundance are compared to cu- mulative incident light during the test runs (Table 2, Figs. 5, 6) and to incident light when the fish were captured (Table 3, Figs. 7, 8). The only physical variable altered between the two years was the light transmittance of the saran screening. During the 1978 test, 75% shade was achieved, and 47% shade was maintained during the 1977 tests. The cumu- lative incident light and incident light values during the tests were about two times greater in the unshaded sections than in the shaded sections in 1977 and about four times greater in the unshaded sections than in the shaded sections in 1978 (Tables 2, 3). This corre- sponds to the difference in light transmittance through the screening between the two years. Although Hoar et al. (1957) determined that juvenile salmon were less photonegative than older fish, the relative age structure of the juvenile salmon used in our study was com- parable between the two years and cannot be construed as an explanation of differences be- tween years. The intensity of light, as mea- sured bv the pvranographs, was about 20% higher in 1978 than in 1977 (Tables 2, 3). If fish were negatively phototactic, we can hypothe- size that the differences in abundance and possibly biomass between shaded and un- shaded sections should have been even greater in 1978 than in 1977. This hypothesis was not clearly substantiated when the results for the percentage of fish biomass and abun- dance were evaluated without regard to inci- dent and cumulative incident light (Figs. 3, 4). We can, however, infer that the hypothesis was substantiated when fish biomass and 30 Great Basin Naturalist Vol. 47, No. 1 40r Y= 31.10-.019X r2=.70 P< .001 n = 40 oTreatment sections • Control sections 0 200 400 600 800 1000 1200 1400 1600 1800 Cumulative incident light (gm cal/cm2) Fig. 10. Relation between cumulative incident light and fish abundance for all test runs, 1977 and 1978 combined. abundance in relation to cumulative incident light (Figs. 5, 6) and to instantaneous incident light (Figs. 7, 8) were compared between the two years. The hypothesis was further sub- stantiated when data from all tests for both years were combined; highly significant cor- relations were found between cumulative in- cident hght and fish biomass and abundance (Figs. 9, 10). Chapman and Knudsen (1980) and Hawkins et al. (1983) report that reduced cover supports higher standing crops of salmonids in western streams. Although this is generally true, the studies cited earlier (for example, Gibson and Keenleyside 1966, But- ler and Hawthorne 1968) have fairly well demonstrated that most salmonids seek shade cover, particularly at high light intensities. Standing crops may therefore be greater in unshaded stream reaches, but within those reaches, the fish probably seek out shaded habitats. We frequently observed fish main- taining position in the shade provided by the screen covers, but darting momentarily into the unshaded area to secure food and then returning to the shade. Our results strongly suggest that shade is an important feature of stream habitat and influ- ences the daytime distribution, abundance, and biomass of juvenile salmonids. Under the conditions of cover without form that we sim- January 1987 MEEHAN ET AL. : EFFECTS OF SHADING ON SALMON 31 ulated and that occur naturally, shade may be a relatively more important feature than in habitats having cover with form, such as over- hanging banks, logs, and other debris on or directly over the stream surface. These latter types of cover cast a shade mosaic on the stream surface and substrate that not only changes constantly with the changing angle of the sun but also affects a much smaller area than would general shade provided by a dense canopy of riparian vegetation. The effectiveness and importance of shade as a cover feature for salmonids likely vary with fish species, age, and the species (or predator-prey) mix. We suggest that measur- ing cumulative incident light may be impor- tant in explaining the daytime distribution, abundance, and biomass of fishes that display strong territorial behavior, such as some salmonids. Vahdating this hypothesis is an area for future investigation. Literature Cited Brusven. M. a. W R Meehan. and J. F. Ward 1986. Summer use of simulated undercut banks by juve- nile chinook salmon in an artificial Idaho channel. North Amer. J. Fish. Manage. 6; 32-37. Butler, R L , and V. M Hawthorne. 1968. The reac- tions of dominant trout to changes in overhead artificial cover. Trans. Amer. Fish. Soc. 97(1): 37-41. Chapman, D. W., and E. Knudsen. 1980. Channelization and livestock impacts on salmonid habitat and biomass in western Washington. Trans. Amer. Fish. Soc. 109(4): 357-363. DeVore, p. W., and R J White 1978. Daytime re- sponses of brown trout (Salmo trtttta) to cover stimuli in stream channels. Trans. Amer. Fish. Soc. 107(6): 763-771. GiB,s()N, R. J. 1966. Some factors influencing the distribu- tions of brook trout and voung Atlantic salmon. J. Fish. Res. Board Canada 23(12): 1977-1980. 1978. The behavior of juvenile Atlantic salmon {Salmo salar) and brook trout {Salvelinus fonti- nalis) with regard to temperature and to water velocity. Trans. Amer. Fish. Soc. 107(5); 70,3-712. Gibson, R. J , and M. H. A. Keenleyside. 1966. Re- sponses to light of young Atlantic salmon {Salmo salar) and brook trout {Salvelinus fontinalis). J. Fish. Res. Board Canada 23(7): 1007-1024. Gibson, R. J., and G. Power. 1975. Selection by brook trout {Salvelinus fontinalis) and juvenile Atlantic salmon {Salmo salar) of shade related to water depth. J. Fish. Res. Board Canada .32(9): 1652-16.56. Hawkins, C P., M. L. Murphy, N. H. Anderson, and M. A WiLZBACH. 1983. Density offish and salaman- ders in relation to riparian canopy and physical habitat in streams of the northwestern United States. Canadian J. Fish. Aquat. Sci. 40(8): 1173-1185. Hoar. W. S., M. H. A Keenleyside, and R. G Goodall. 1957. Reactions of juvenile Pacific salmon to light. J. Fish. Res. Board Canada 14(6): 815-830. McCrimmon, H.. and W -H Kwain. 1966. Use of over- head cover by rainbow trout exposed to a series of hght intensities. J. Fish. Res. Board Canada 23(7): 983-990. PiNHORN, A T , and C W Andrews 1963. Effect of pho- toperiods on the reactions of juvenile Atlantic salmon {Salmo salar L.) to light stimuH. J. Fish. Res. Board Canada 20(5): 1245-1266. Reiser, D. W., andT C Bjornn 1979. Habitat require- ments of anadromous salmonids. In W. R. Mee- han, tech. ed., Influence of forest and rangeland management on anadromous fish habitat in west- ern North America. U.S. Department of Agricul- ture, Forest Service, Gen. Tech. Rept. PNW-96. Pacific Northwest Forest and Range Experiment Station, Portland, Oregon. 54 pp. Sullivan, C. M , and K C Fisher. 1954. The effects of light on temperature selection in speckled trout Salvelinus fontinalis (Mitchill). Biol. Bull. 107(2):278-288. DROSOPHILA PSEUDOOBSCURA (DIPTERA: DROSOPHILIDAE) OF THE GREAT BASIN IV: A RELEASE EXPERIMENT AT BRYCE CANYON Monte E. Turner' Abstract —Some populations of Drosophila pseudoohscura in the Great Basin have verv httle genetic variation for third chromosome mversion gene arrangements. These populations are essentially monomorphic for the Arrowhead gene arrangement. At Bryce Canyon, Utah, individuals with other gene arrangements (Standard, Pikes Peak and Treelme) were released and their frequencies monitored. One generation after release, the released arrangements had mcreased in frequency from 0.7% to almost 10%. After overwintering, the arrangement frequencies were not statistically different from the prerelease samples. The samples did demonstrate a low-level retention of the released Pikes Peak arrangement. The decline in the released arrangements was probably the result of large population size at Bryce Canyon and the bottleneck effects of overwintering. The results do not seem consistent with a model of the released arrangements having a lowered fitness. a Natural populations of Drosophila pseti- doobscura have been studied for over 40 years. Populations were originally cytologi- cally characterized for the gene arrangements of the third chromosome (Dobzhansky and Sturtevant 1938), and these arrangement fre- quencies were monitored. The different gene arrangements are the result of a phylogeny of mostly overlapping inversions of segments of the third chromosome (Dobzhansky 1944). Because of greatly reduced recombination within the inverted segments in heterokary- otypes, these inversions act to tie together portions of the chromosome into large super- genes. These supergenes (gene arrange- ments) are inherited and behave in popula- tions as alleles at a single locus. Some natural populations of D. pseudoohscura have been sampled repeatedly since the 1930s (Ander- son et al. 1975) and provide an excellent his- torical basis for current research. These con- tinuing geographic surveys over the range of D. pseudoohscura have led to the division of the species into five geographic races, each characterized by the gene arrangements present and their frequencies (Dobzhansky and Powell 1975). These races are: Pacific Coast Intermountain Plateau Rocky Mountains and Texas Northern Mexico Southern Mexico and Guatemala Race 2, the Intermountain Plateau, has been characterized as nearly monomorphic for the Arrowhead (AR) gene arrangement, while the other races are highly polymorphic. Populations of the Intermountain Plateau were originally sampled and characterized in the early 1940s. Those areas which have been sampled regularly (Bryce Canyon, Utah; Leh- man Caves, Nevada; and three localities in Arizona) have remained essentially the same as the original samples (Anderson et al. 1975). During 1976 and 1977 six areas in the north- ern Intermountain Plateau area were sam- pled; some of these sites had not been sam- pled since they were originally characterized in the 1940s and 1950s. This area, which had previously been characterized as nearly monomorphic AR, had undergone great changes both in the particular gene arrange- ments present and their frequencies (Turner and Jeffery 1980). These populations now have an arrangement array very similar to that found in the Rocky Mountain populations (Race 3) including the endemic Fort Collins arrangement, previously found only in a few areas of the Rocky Mountains. It was hypothe- sized that these changes came about because of gene flow into these northern Intermoun- tain Plateaus (Race 2) from the Rocky Moun- tains (Race 3) (Turner and Jeffery 1980). The release of genes into natural popula- tions has been attempted previously with pos- itive results. Bryant (1976) released D. pseu- doohscura with a rare esterase allozyme into a Department of Biology, University of Akron, Akron. Ohio 44.325. 32 January 1987 Turner: Drosophila Release Experiment 33 small oasis population in Death Valley, Cali- fornia, in an attempt to swamp the population and then determine the amount of immigra- tion in the population. Thirty-eight days after the release, the frequency of the genetic marker had increased from 2% before the re- lease to approximately 80%. Dubinin and Tiniakov (1946) released D. funebris with an inversion from another locality into a popula- tion where that inversion was rare. The fre- quency of the released inversion was origi- nally 0.35% and increased to a high of 49.5% approximately one generation after the re- lease. These two results show that it is possi- ble to introduce outside genes or gene ar- rangements (even those that have been in the laboratory for some time) into a natural popu- lation and that they can become integrated into that population at fairly high frequencies. This research investigates, through the use of a release experiment, the inversion gene arrangement polymorphism in an Intermoun- tain Plateau population of Drosophila pseu- doobscura. Materials and Methods Sampling Sites and Methods. — Three lo- cations in Biyce Canyon National Park, Utah, were selected as sampling sites. These three sites are separated by distances such that mi- gration by individuals between the sites was thought to be negligible. The southern and northern sampling sites are 14 km apart. The middle site is 5 km from the southern site and 9 km from the northern site. These three areas are quite diverse and probably encompass the entire range of possible D. pseudoobscura habitats in Bryce Canyon. The southern sam- pling site is the least arid and the most similar of the three sites to the northern Intermoun- tain Plateau. Because of this similarity, this site was chosen for the release. During 21-28 June 1978, samples were obtained from each of these three sites. Individual females ob- tained from nature were used to establish isofemale lines, and Fl larvae were character- ized cytologically for the gene arrangement of the third chromosome using standard Drosophila salivary techniques. The Release — On the three days immedi- ately following the completion of the initial samples, D. pseudoobscura homozygous for Standard (ST), Treehne (TL), or Pikes Peak (PP) gene arrangements were released in the southern sampling area. The flies to be re- leased were grown in large population cages which support approximately 12,000 adult flies. The releases were accomplished by opening these cages and allowing the adults to escape. Thus the released flies were a mixed sample of age and sex, and no attempt was made to release only virgin flies. This was done in five separate release events over the span of three days, one release daily during the evening activity period and on two days releases during the morning activity periods. Approximately equal numbers (approx. 12,000) of each homozygous type were re- leased during each event, and the total num- ber of individuals released was approximately 200,000. No flies were released in the other two sampling sites. Afl three sites were subse- quently sampled and characterized geneti- cafly during August 1978 and June, August, and September 1979. Origin of Released Chromosomes. — The released PP stock was derived from a collec- tion made in June 1977 at American Fork, Utah. In this collection PP had a frequency of 18.9%. The TL stock came from a collection in Big Cottonwood Canyon, Utah (near Salt Lake City), in June 1977. The frequency of TL in this population was 25.0% (Turner and Jeff"- ery 1980). The ST stocks were from Mather, California, and have been maintained in the laboratory since 1959. Results and Discussion The frequencies of the third chromosome gene arrangements from the initial sample (June 1978) are given in Table 1 along with the totals from previous samples of Bryce Canyon. The June 1978 totals are significantly different from the previous samples total (X = 13.45, p < .01, 3 df ) but not significantly different from the latest (1973) sample of Bryce (X' = 1.51, p < .25, 1 df). The three sample sites have no significant differences in gene arrangement frequencies (Table 1) (X" = 1.4, p< .79, 2 df ). The June 1978 samples had two arrangements, Treeline (TL) and Bryce (BR), not previously found in Bryce Canyon samples. The BR arrangement is a new ar- rangement, an inversion of Arrowhead (AR) with breakpoints 71B and 80C. The release took place after the June 1978 34 Great Basin Naturalist Vol. 47, No. 1 Table 1. Percentage of third chromosome gene arrangements of D. p.->eiidoobscura from Brvce Canyon before the release (n = number of chromosomes). Site Sampling date AR PP CH TL ST BR n Bryce Canyon 1940 1950 1957 1965 1973 (Anderson et al. 1975)_ June 1978 June 1978 June 1978 96.0 92.9 93.2 92.0 99.3 2.6 1.5 2.0 2.4 1.6 4.0 — 2.0 4.8 2.6 2.5 .7 — 100 84 190 200 1.36 Totals Bryce Canyon Northern site Middle site Southern site 94.6 97.8 97.0 98.4 1.1 2.1 2.2 1.8 1.0 0.3 2.1 1.0 0.3 0,3 710 178 398 .304 Totals June 1978 97.6 — 1.6 0.1 0.6 0.1 880 T.ABLE 2. Percentage of third chromosome gene arrangements of D, pseudoobscura in postrelease samples from Bryce Canyon, Utah (August 1978) (n = number of chromosomes). Locality Days since release AR CH ST PP TL SC n Northern Middle Southern day 42 & 43 day 42 & 43 day 40 dav 41 dav 42 96.8 96.0 97.1 96.8 90.5 2.4 2.5 1.1 0.8 0.5 1.0 1.2 0.5 1.0 3.6 0.5 2.1 4.8 1.0 126 202 102 94 84 samples and only in the southern site. The populations were sampled again in August 1978 (Table 2). While the nonrelease sites have not changed significantly, the daily gene frequencies from the southern area show the release to have been successful. On days 40 and 41 (since the release), the frequencies (Table 2) are similar to the prerelease sam- ples, but on day 42 the frequency of AR de- creased from over 96% the previous day to 90.5%. This decrease in frequency is due to the increased frequencies of the released TL and PP gene arrangements. Again, this de- creased AR is not seen in either of the two nonrelease sites even though they were sam- pled past day 41. These frequency increases are the result of the emergence of the Fl from the released individuals. These data show the released chromosomes (ST, TL, and PP) to have increased from 0.33% in the initial sam- ples to almost 10% 42 days after the release. This appearance 42 days aifter the release indi- cates at Bryce Canyon the generation time of 42 days. At this length, these populations could have only three or four generations a vear. From September until April or May tem- peratures at Bryce Canyon are too cold to support an active D. pseudoobscura popula- tion. Thus, the next samples following the release were during the summer 1979. Three collections were made, and the gene arrange- ment frequencies are presented in Table 3. There are no statistically significant differ- ences between samples or sampling sites (X^ = .74, p < 0.6, 2 df). Pikes Peak (PP) was the only gene arrangement not seen in the prere- lease samples but found in the 1979 samples. Although a very large number of individu- als were released, the resulting change in gene frequencies was small. Reduced survival of the released individuals probably was re- sponsible for a portion of the decline. Dobzhansky and Wright (1943) calculated the survival of released 5-7 day-old orange-eyed D. pseudoobscura. They estimated that ap- pro.ximately 90% survive per day. That is probably an overestimate for the current re- lease since some of the released flies were older (and younger) than their samples. Also, Bryce Canyon is 3,000 ft higher in altitude than Dobzhansky and Wright's experimental January 1987 Turner: Drosophila Release Experiment 35 Table 3. Percentage of third chromosome gene arrangements from sites in Bryce Canyon for snnnner following August 1978 release (n - nnmher of chromosomes). Date Site AR CH ST PP n June 1979 Northern Middle Southern 94.1 98.3 98.0 0.9 1.5 4.4 0.9 0.5 1.5 68 116 204 Total 97.4 1.0 1.3 0,3 388 Aug. 1979 Northern Middle Southern 97.2 100.0 97.9 1.7 2.1 1.2 — 176 50 144 Total 97.8 1.6 0.5 — 370 Sept. 1979 Northern Middle Southern 96.2 100.0 93.9 2.8 3.8 1.5 0.9 0.8 106 40 130 Total 95.7 2.9 0.7 0.7 276 1979 Total 97.1 1.7 0.9 0.3 10.34 location. In fact, in their study, when the weather was particularly arid, their recapture rates dechned significantly. The increased al- titude of Bryce Canyon, with reduced humid- ity and greater temperature extremes, proba- bly contributes to a survival rate lower than their 90% per day estimate. But, more impor- tantly, in the current release the concern is not on the survival of an individual but the genetic contribution to the next generation. A released female may survive, but unless she can find a suitable oviposition site and suffi- cient food, she will not contribute genetically to the next generation and the genes she car- ried will be lost. Laboratory experiments with D. pseudoobscura females show over 90% re- duction in productivity (number of offspring) under nutritional stress (Turner and Ander- son 1983). For these reasons the contributions of released females were probably small in magnitude. In all cases the released chromo- somes in the second sample were found as heterozygotes. The contribution of already- mated released females would have been Fl homozygotes. Since virgin females were not released and no homozygotes were found, probably most of the released chromosomes that became integrated into the gene pool were the result of released males mating with wild (AR/AR) females. In retrospect, for a population like Bryce Canyon (one very close to the ecological bounds of the species) a re- lease of males only may be the best strategy. In the prerelease samples, none of the three sampling sites shows significant differ- entiation. This lack of spatial differentiation between sites is surprising considering the ecological difference between sites. For in- stance, only ponderosa pine (Piniis pon- derosa) is found in all three sampling sites, and it is rare in the southern site. There is also a drop in altitude from the southern site (8,300 ft) to the northern site (7,200 ft). These results may indicate that the Arrowhead arrange- ment (AR) is responding to some general com- ponent of the environment such as tempera- ture. If it were responding to something specific in the environment, different sites with different habitats would be expected to show different frequencies. The homogeneity between sample sites is consistent with the observation that much of the Great Basin D. pseudoobscura populations are characterized by a high frequency of the AR arrangement (Anderson et al. 1975, Dobzhansky and Pow- ell 1975). One other interesting aspect of these sam- ples (August 1978, Table 2) is the appearance of the Santa Cruz (SC) gene arrangement at Bryce Canyon. This arrangement was not in the release, and its appearance at this time is only coincidental. This arrangement is usually found along the Pacific Coast of California and in southern Mexico. In previous samples of almost 1,600 chromosomes (Table 1) SC had never been identified at Bryce. In samples from related areas (Nevada, Arizona, and Utah) (Anderson et al. 1975, Turner and Jef- 36 Great Basin Naturalist Vol. 47, No. 1 fery 1980), nearly 5,000 chromosomes have been characterized and SC has never been identified in this region. Whether SC has al- ways been at Bryce but in extremely low fre- quency or whether this SC came with an indi- vidual immigrant (active or passive) fly from a population where the SC arrangement is found cannot be determined at this time, al- though the latter seems the more probable alternative. TL, which had reached levels close to 5% in the southern sampling area 42 days following the release (Table 2), was not observed in over 1,000 chromosomes examined in 1979, of which almost 500 came from the southern (release) area (Table 3). A second gene ar- rangement in the release. Standard (ST), did not show a significant increase in postrelease samples (Table 2) and had approximately the same frequency in 1979 (Table 3) as that seen in the 1978 prerelease samples (Table 1). In the June 1979 sample from the northern site, Standard has a frequency of 4.4% (Table 3), but it decreased and was not found in the August 1979 sample from this site. Standard did not show a frequency increase in the re- lease area (Tables 1,2). The observation from the northern site could be the result of migra- tion of the released flies (or their offspring) to the northern site or the result of sampling error due to small sample sizes. The results of these two arrangements (TL and ST) are simi- lar and consistent with no long-term effect of the release. The PP gene arrangement had not been found in Bryce since 1964, but it did reach a level of 3.6% following the release (Table 2) and was found in low frequency (0.3%) in 1979. During the 1979 samples PP was found in all three sample sites and is most probably a low-level retention following the incorpora- tion of the released PP arrangement into the Bryce Canyon gene pool. This result would indicate that the earlier assumption that the sites were far enough apart to ignore migra- tion was incorrect. In the two to three genera- tions since the release all three sites have two (PP and ST) of the three released arrange- ments, a linear distance of 14 km. With this level of migration we can consider this area as supporting one large breeding population. In this large population an introduced gene (re- leased or migrant) may be swamped by the local (AR) gene pool, without being able to enter a small isolate and increase in frequency (as the result of either stochastic or selective mechanisms). This type of population struc- ture would minimize the effects of migration in changing gene frequencies. Additionally, to persist in this population, an arrangement (or gene) must survive the winter. When high-elevation populations overwinter, they undergo a severe bottleneck in population size because of the low tempera- tures. How D. pseudoob.scura overwinter is not known, but overwintering is unquestion- ably a severe process. In laboratory experi- ments on overwintering ability only a small frequency of the flies survive cold shocks of just a few days (Jefferson et al. 1974), and over a winter of six to eight months only a very small number of individuals may survive. In this way, the released arrangements may not survive the winter and the sampling effect of the resultant population bottleneck. This bot- tleneck would eventually cause the popula- tion to lose variability through genetic drift. These results also bear on the question of overwintering; that is, whether these higher- altitude populations overwinter in place (at altitude) rather than be repopulated each spring from lower-altitude overwintering refugia. The latter hypothesis is similar to that observed in the desert populations of D. pseu- doobscura where populations are refounded each year from neighboring mountains after the hot summers have eliminated the popula- tions (Jones et al. 1981). The persistence of the Pikes Peak (PP) arrangement would be consis- tent with an overwintering-in-place hypothe- sis and not a repopulation each spring from lower-altitude populations. A decrease in frequency due to small fitness differences would take many generations. The PP and TL arrangements were isolated from areas with an environment and elevation roughly similar to Bryce Canyon. Both ar- rangements were in relatively high frequency where found originally, PP being almost 20% and TL 25%. Thus, if fitness differences do exist between the released chromosomes and the native AR, they most likely would be small. Since D. pseudoobscura do not repro- duce during the winter, from August 1978 until June 1979 there is only one generation and at most two. The rapidity of the decrease would suggest that if the decrease were due to an inherent selective disadvantage, this fit- January 1987 Turner: Drosophila Release Experiment 37 ness diflference must be extremely large. The rapid decrease would seem more consistent with the swamping effect of a large population size and random drift in ovei-wintering popu- lations. Acknowledgments I am grateful for the assistance of the Na- tional Park Service staff at Bryce Canyon Na- tional Park and for discussions of this project with Wyatt Anderson and Duane E. Jeffery. This research was supported by an NSF doc- toral dissertation improvement grant. Literature Cited Anderson, W. T. Dobzhansky, O. Pavlovsky, J. Powell. andD.Yardley. 1975. Genetics of natural popula- tions. XLII. Three decades of genetic change in Drosophila pseudoohscura. Evolution 29: 24-36. Bryant, S. H 1976. The frequency and allelism of lethal chromosomes in isolated desert populations of Drosophila pseudoohscura. Unpublished disser- tation, University of California, Riverside. Dobzhansky, T. 1944. Chromosomal races in Dro.wp/H/« pseudoohscura and Drosophila pcrsimilis. Pages 47_144 in T. Dobzhansky and C. Epling, Contri- butions to the genetics, taxonomy and ecology of Drosophila pseudoohscura and its relatives. Carnegie Institution of Washington Publication 554. 133 pp. Dobzhansky, T., and J K Powell. 1975. Drosophila pseudoohscura and its American relatives Drosophila persimilis and Drosophila miranda. In R. C. King, ed.. Handbook of genetics: inverte- brates of genetic interest. Vol. 3. Dobzhansky. T.. and A. H Sturtevant. 19.38. Inversion in the chromosomes of Drosophila pseudooh- scura . Genetics 23: 28-64. Dobzhansky, T., and S. Wright. 1943. Dispersion rates in Drosophila pseudoohscura. Genetics 28: 304-340. Dubinin, N P , and G. G. Tiniakov. 1946. Inversion gra- dients and natural selection in ecological races of Drosophila funehris. Genetics 31: 537-.545. Jefferson, M. C, D. W Crumpacker, and J S. Williams. 1974. Cold temperature resistance, chromosomal polymorphism and interpopula- tional heterosis in Drosophila pseudoohscura. Genetics 76: 807-822. Jones, J. S , S H. Bryant. R C Lewontin, J. A Moore, andT Prout. 1981. Gene flow and the geographi- cal distribution of a molecular polymorphism in Drosophila pseudoohscura. Genetics 98: 157-178. Turner. M E . and D E. Jeffery. 1980. Drosophila pseudoohscura of the Great Basin. II. Third chro- mosome arrangements of selected northern Utah populations. American Naturalist 115: 771-779. Turner. M E , and W W Anderson. 1983. Multiple mating and female fitness in Drosophila pseu- doohscura. Evolution 37: 714-723. ROBBER FLIES OF UTAH (DIPTERA: ASILIDAE) C. Riley Nelson' Abstract —Reported are 158 species of Asilidae (Diptera) in 50 genera from Utah. Keys to subfamilies genera and species are given, along with information on seasonal and distributional occurrence in Utah. Seventy-six maps and 56 line drawings show the Utah distribution of each species and illustrate important characters used in the keys. A table summarizes the current status of names used in earlier state lists. The Asilidae (Diptera) have long attracted the attention of collectors. As a result, numer- ous specimens have been deposited in collec- tions in the state of Utah. The systematics of the family have been studied rather inten- sively so that the taxonomic status of most groups is known. The purpose of this study is to assemble the numerous records and to identify the species of asilids caught in Utah. The catalog of Diptera (Stone et al. 1965) shows that about 50 species of asilids are ei- ther listed as occurring in Utah or are in- cluded in the broad geographical ranges de- lineated under a given species. A preliminary examination of the specimens from the Utah State University Entomological Museum re- vealed that identifications made by prominent workers of the family existed for over 150 different species. A careful examination of col- lections of asihds from the state revealed 158 species in 50 genera. Review of Literature Brown (1929) pubhshed the first paper dealing with Asilidae of Utah. He listed 22 species of robber flies as occurring in Utah, one of which was not determined to species. He included drawings of the genitalia of most of these species. Table 1 summarizes the cur- rent status of the species listed by Brown (1929). Knowlton and Harmston (1938) published a list of Asilidae found in Utah. A summary of the current status of these species is given in Table 2. A further list of asilids captured in Utah was given by Knowlton, Harmston, and Stains Table 1. Current status of species listed in Brown (1929). 1. Ospriocerus abdominalia (Say) 2. Stenopogon modestiis Loew 3. Stenopogon consanguineus Loew 4. Stenopogon californiae (Walker) 5. Stenopogon sp. female 6. Heteropogon ludius (Coquillett) 7. Dasijllisfernaldi Back 8. Deromijia bigoti (Bellardi) 9. Proctacanthiis arno Townsend 10. Erax harhatus (Fabricius) 11. Erax interniptus (Macquart) 12. Erax stamineus WiUiston 13. Erax sidjpilosns SchaefFer 14. Mallophora fulviventris Macquart 15. Mallophora guildiana Williston 16. Promachus bastardii (Macquart) 17. Promachus nigripes Hine 18. Asihi.s lecythiis Walker 19. Asihis tenehrosits Williston = O. abdominalis = S. inqiiinattis Specimens are Scleropogon neglectus Specimens are S. rufibarbis Not enough information Wilcox lists as H. senilis = Laphriafernaldi = Diogmites grossus = P. nearno = Efferia albibarbis = Triorla interrupta = Efferia staminea Neither Wilcox (1966) nor I saw specimens of this species. Unrecognizable to Cole and Pritchard (1964). = Megaphonis guildiana = P. dimidiattis Specimens are P. uldrichii. Utah specimens are Machimus occidentalis. = Machimus ariseus 'Department of Biology, Utah State University, Logan, Utah 84322. Present address: M. L. Bean Museum. Brigham Young University, Provo, UtahS4602. 38 January 1987 Nelson: Utah Robber Flies 39 Table 2. Changes in status of species listed in Knowlton and ILirmston (1938). L Ablaiitus trifariiis Loevv 2. Andrenosoma abdominalis (Brown) 3. Asihis callidus 4. A. compositus Hine 5. A. erijthrocnemius Hine 6. A. grad/wsWeidemann 7. A. mesae Tucker 8. A. occidentalis Hine 9. A. f(?nc/jrosH.s- Williston 10. Bomboinima fernaldi (Back) 11. Cyrtopogon callipedihis Loew 12. Deromyia bigoti Bellardi 13. Dioctria parvula Coquillett 14. Efferia Candida Coquillett 15. Erax spp. 16. Erax argyrosoma Hine 17. Erax barbatus Fabricius 18. E. californicus 19. E. (fw/ni/.s Williston 20. E. interruptiis 21. E. knotvltoni Bromley 22. £. pallididus Hine 23. E. texana Banks 24. Eucyrtopogon macidosus Coquillett 25. Heteropogon lautiis Loew 26. Mallophora gitildiana Williston 27. Mallophora faiitricoides Curran 28. Neoitamushardyi Bromley 29. Nicodes punctipennis Melander 30. Osprioceriis ventralis (Say) 31. Proctacanthus arno Townsend 32. P. cacopiloga Hine 33. Promachus nigripes Hine 34. P. quadratus Weidemann 35. Scleropogon longultis Loew 36. Stenopogon helvolus Loew 37. Stenopogon neglectiis Bromley 38. Stenopogon obscurivenths Loew 39. S. picticornishoew Utah specimen is Omninablauttis nigronotu)n = Cerotainiops abdominalis = MacJiimus callidus = Polacantha coniposita Specimens are Machimus paropus Specimens are Polacantha coniposita = Negasilus mesae = Machimus occidentalis = Machimus griseus = Laphria fernaldi No specimens seen; this is a California species; Utah speci- mens were probably C. montanus Diogmites grossus Probably D. henshawi Specimen is E. benedicti Efferia spp. Utah specimens are Efferia benedicti = Efferia albibarbis No specimen seen, specimen was probably Efferia benedicti Nomen nudum = Triorla interrupta = Efferia benedicti Not seen in collections Not seen in collections No specimen seen Utah specimen is H. maculinervis = Megaphorus guildiana = Mallophora fautrix = Asilus auriannulatus = N. utahensis = O. abdominalis = P. near no = Proctacanthella cacopiloga Utah specimens are P. aldrichii Eastern species; Utah specimen is P. dimidiatus = Ospriocerus longulus Specimen is Scleropogon indistinctus = Scleropogon neglectus Utah specimens are S. martini = Scleropogon picticornis (1939). A review of the species from that pub- hcation and their current status is given in Table 3. Johnson's (1936) unpubhshed master's the- sis is an important contribution to the study of the feuna of the state. He hsted 73 species as occurring in Utah. Table 4 summarizes the changes in the status of the species hsted in Johnson (1936). Johnson's specimens are in the Brigham Young University collection and were examined during this study. Numerous other records of asilids caught in Utah are scattered throughout the literature. These are listed unmarked under the discus- sions of individual species. Methods Utah collections of Asilidae were examined at Utah State University, Brigham Young University, the University of Utah, Southern Utah State College, Dixie College, and the College of Eastern Utah. Additionally, a search through literature dealing with Asili- dae was iTiade, and records of specimens col- lected in Utah were included in the synopsis of each species. Numerous areas throughout the state were visited, and extensive collections of Asilidae were made during this study. Areas which received particular attention were: Washing- 40 Great Basin Naturalist Vol. 47, No. 1 Table 3. Changes in status of species listed in Knowlton, Harmston, and Stains (19,39). 1. Anisopogon lauttis Loew 2. Asilus avidus Van der Wulp 3. A. belli Curran 4. A. delicatulus Hine 5. A. enjthrocnemhis Hine 6. A. occidentalis Hine 7. A. paropw,s Walker 8. Bomhomima fernaldi Back 9. Dioctria pleiiralis Banks 10. Efferia Candida Coquillett 1 1 . Erax harhatus Fabricius 12. E. bicaudatus E. dubiiis Williston E. zonatus Hine Holopogon phaeonotiis Loew H. seniculus Loew Laphystia sexfasciatus Say 18. Mallophora bromleiji Curran 19. M. purdens Pritchard 20. M. pulchra Pritchard 21. Neoitamti.s hardiji Bromley 22. Nicocles piinctipennis Melander 23. Ospriocerus ventralis Coquillett 24. Proctacanthus arno Townsend 25. Promachus nigripes Hine 26. Stenopogon helvohis Loew 27. Stenopogon neglectiis Bromley 28. Stenopogon obscuriventris Loew 29. S. picticornis Loew 13. 14. 15. 16. 17. Probably Heteropogon senilis Specimens are Machimus adustus = Negasilus belli Specimen unidentifiable Specimens are Machimus paropus = Machimus occidentalis = Machimus paropus = Laphria fernaldi Specimens are Dioctria vera Specimens are E. davisi = Efferia albibarbis Specimens are Efferia f re wingi Nomen nudum = Efferia zonata Specimens are H. albipilosus Specimens are H. albipilosus Specimen is L. tolandi = M. faittrix = Megaphorus willistoni = Megaphorus pulcher = Asilus auriannulatus = N. utahensis = O. abdominalis (Say) = P. nearno Martin Specimens are P. aldrichii Specimens are Scleropogon coyote = Scleropogon neglectus Specimens are S. mar-tini = S. picticornis ton County, the only area of the state where species of Mohave Desert origins could be collected; the Raft River Mountains; Cache County; Box Elder County; Juab County; Emery County; Grand County; and San Juan County. The taxonomic synopsis presented in this paper consists of information regarding origi- nal citation and author, type locality, type repository, all of which were obtained from the literature. The county and seasonal distri- butions of each species were taken from speci- men labels. The seasonal distributional data are expressed as a range of earliest and latest known collection dates for Utah specimens. Keys to subfamilies, genera, and species were constructed using published informa- tion and new insights. A map was produced showing the distribution of each species listed, and 56 figures were drawn using a cam- era lucida on a Wild M8 stereomicroscope. The figures illustrate important characters used in the keys. 1. R2+3 ending in costa (Figs. 40, 46) 2 — Ro+3 joining Rj, closing cell rj (Fig. 43) 3 2(1). Abdominal segment 2 elongate, five or more times as long as wide; resembling, somewhat, small damselflies Leptogastrinae — Abdominal segment 2 shorter, not more than five times as long as wide; not particularly re- sembling damselflies Dasypogoninae 3(2). Antennae without a terminal style, ending l^luiit'y Laphriinae — Antennae bearing a terminal style Asilinae Key to the Genera of Utah Leptogastrinae and Dasypogoninae (Modified from Wood 1981) 1. Abdominal segment 2 elongate, five or more times as long as wide; abdomen very thin and elongate Leptogaster Meigen" — Abdominal segment 2 shorter, not more than five times as long as wide; abdomen generally shorter and stout 9 2(1). Foretibia bearing a terminal, clawlike spur on ventral surface which is thicker and sigmoid (Figs. 54-55) : 3 Keys Key to the Subfamilies of Utah Asilidae Much difficulty was met using the key given by Martin (1957). Although several species of Leptogaster are present in Utah collections, reliable spe- cies determinations were not made. The distribution of this genus in Utah is given in Fig. 100. January 1987 Nelson: Utah Robber Flies 41 Table 4. Changes in status of species listed in Johnson (1936). L Ahlautus squamipes Cole 2. Andrenosoma similis (Brown) 3. Asilus avidus Van der Wulp 4. A. brevicomtis Hine 5. A. mesae (Tucker) 6. A. occidentalis Hine 7. A. paropus Walker 8. A. feneirosws Williston 9. Bombomima fernaldi (Back) 10. Chnjsoceria pictitarsis (Bigot) 11. Cophura texana Bromley 12. Cyrtopogon dasijllis Williston 13. C. leucozona Loew 14. C. nwgaf or Osten Sacken 15. Diogmites pulchra (Back) 16. Ecthopoda sp. 17. Erax argyrosoma (Hine) 18. EraxbarbatusFahricius 19. Erax bicaudatus Hine 20. Erax Candidas (Coquillett) 21. Erax caneUiis Bromley 22. Erax cingulatus Bellardi 23. Erax dubius (Williston) 24. Erax interruptus (Macquart) 25. Erax pilosus Hine 26. Erax stramineiis Williston 27. Holopogon senicuhis Loew 28. Laphystia limatuhis Coquillett 29. L. rufiventris Curran 30. Lestomyia fraudigera Williston 31. Mallophora bromleyi Curran 32. Proctacanthella leucopogon (Will. 33. Proctacanthiis arno Townsend 34. Promachus bastardii (Macquart) 35. P. nigripes Hine 36. Stenopogon californiae (Walker) 37. S. helvohis (Loew) 38. S. obscuriventris Loew Specimens are A. mimiis = Cerotainiops abdoinitialis Specimens are Machimus adusfiis = Neoitamus bnwicumu.s = Negasihis mesae = Machimus occidentalis = Machimus paropus Specimens are Machimus griseus -— Laphria fernaldi = Callinicus pictitarsis No specimens seen Specimens are C. dasylloides = C. montanus Specimens are C. banksi Specimens are Diogmites grossus No label; spelling Ecthodopa Specimens are Efferia benedicti = Efferia albibarbis (Macquart) Probably Efferia f re wingi Specimens are Efferia davisi Specimens are Efferia benedicti No specimens seen; not Nearctic Nomen nudum = Triorla interrupta No specimens seen Specimens are Efferia benedicti Specimens are Holopogon albipilosus Specimen is Laphystia rubra Specimens are Laphystia tolandi Specimen is Lestomyia sabulona = Mallophora fautrix No specimens seen = Proctacanthiis nearno Damaged; probably P. dimidiatus Specimens are P. aldrichii Specimens are S. rufibarbis Probably Scleropogon neglectus Specimens are S. rufibarbis Fig. 1. Proctacanthus nearno Martin, right wing: A,, first anal vein; C, costa; CuAi, first anterior branch of cubitus; cua,, anterior cubital cell; CuA,, second anterior branch of cubitus; d, discal cell; h, humeral crossvein; M„ first branch of media; m,, first medial cell; M,, second branch of media; m., second medial cell; M3, third branch of media; m,, third medial cell; R,, first branch of radius; r,, first radial cell; R,.,, fusion of second and third branches of radius; r,, third radial cell; R4, fourth branch of radius; r„ fourth radial cell; R5, fifth branch of radius; r,, fifth radial cell; Sc, subcosta. 42 Great Basin Naturalist Vol. 47, No. 1 Gibbosity Gibbosity Figs. 2-5. Heads of Utah Asilidae; 2, Sfenopogon rufiharbis Bromley, lateral aspect; 3, Stenopo{i,on inquinatus Loew, lateral aspect; 4, Lasiopogon monticola Melander, cephalic aspect; 5, Neoitamus brevicomiis(Hine) lateral aspect. — Foretibia without a terminal differentiated spur on ventral surface 12 3(2). Differentiated spur of foretibia meeting a raised denticulate area on basitarsus (Fig. 54) 4 — Differentiated spur of foretibia not meeting a differentiated denticulate area on basitarsus (Fig. 55) 7 4(3). Face inflated and haired on lower two- thirds Lestotmjia sabulona Osten Sacken — Face flat, hair confined to lower one-third ... 5 5(4). Cell m3 open; two flagellomeres present, the second being small, bearing a pit with apical bristle Saropogon mohaivki Wilcox — Cell m, closed; one llagellomere 6 6(5). Scutellar bristles present Diogmites Loew — Scutellar bristles absent Blepharepium sonorensis Papavero & Bernardi 7(3). Pulvilli present 8 — Pulvilli absent H 8(7). Face inflated on lower two-thirds or more; ante- rior mesonotum bearing a manelike crest of hairs on midline Comantella Curran — Face flat or slightly rounded; mesonotal crest absent 9 9(8). Style of antenna anteapical, in a notch at about midlength of dorsal surface of flagellomere 1; ab- domen pitted . . . Taracticus ruficaudus Curran January 1987 Nelson: Utah Robber Flies 43 — Style apical; abdomen not pitted 10 10(9). Wings with distinct spots on most crossveins and furcations, otherwise hyaline; male with only six visible tergites, last two visible ter- gites widened and covered with dense silvery pollen Nicocle.s Jaennicke — Wings hyaline more washed with brown, spots, if present, indistinct Cophiira Osten Sacken 11(7). Presutural dorsocentral bristles present; length less than 5 mm Omninahlaiitus (Hgronofum Wilcox — Presutural dorsocentral bristles absent; length greater than 7 mm Hodoplujlax hasinncri Pritchard 12(2). Sides of frons greatly divergent toward vertex (Fig. 4) ' 13 — Sides of frons snbparallel or converging to- ward vertex I'l 13(12). Face strongly inflated and haired on lower three-fourths Lasiopogon Loew — Face but slightly convex; mystax confined to lower margin Stichopogon Loew 14(12). Face and frons narrow; head about as wide as high and appearing small in proportion to thorax 15 — Face and frons wider; head wider than high . 17 15(14). Hypopleuron (katatergite) lacking bristles or hairs (Fig. 31) Stenopogon Loew — Hypopleuron bearing bristles or hairs (Fig. 30) 16 16(15). Flagellomere 1 at most one and three-fourths length of antennal segments 1 and 2 com- bined; long, slender terminal style present . Scleropogon Loew — Flagellomere 1 at least two times length of antennal segments 1 and 2 combined; termi- nal style, if present, short . . . Ospriocerus Loew 17(14). R2+3 bent sharply forward near apex, making nearly a 90 degree angle with wing margin (Fig. 45) Laphijstia Loew — R2+3 not bent sharply forward to make such an angle with wing margin (Fig. 40) 18 18(17). Basal half of wing darkened; eyes set off from face along lower margin by grooves running along vertical margin of eyes; CuAi and A, fused before wing margin Haplopogon ittahensis Wilcox — Basal half of wing not darkened, although may be spotted; eyes not set off by vertical grooves; CuAo and A; not joining before wing margin (except in Myelaphiis) 19 19(18). Mystax limited to lower one-third of face or with only a few hairs near antennae in addi- tion to lower mystax 20 — Mvstax extending more than halfway up face 22 20(19). Hind femur and tibia club-shaped; R4 reach- ing wing margin anterior to wing tip Dioctria Meigen — Hind femur and tibia not club-shaped, at most slightly expanded near apex 21 21(20). Flagellomeres 1 and 2 lobed at apex Mijelaphus lohicornis Osten Sacken — All flagellomeres simple, not lobed Dicolomis sparsipilustim Back 22(19). Pulvilli absent; flattened, scalelike hairs present on thorax, legs, and wing base Ablautus Loew — Pulvilli present; scalelike hairs absent 23 23(22). Midtibia bearing a pair of stout spines at apex which are directed outward at an angle near 90 degrees Callinicus Loew — Midtibia with all apical spines directed dis- tally 24 24(23). Wing with dark spot on r-m, furcation of R4 and R5 and at apex of cell d, other spots may also be present 25 — Wings hyaline or darkened; spot pattern not as above 26 25(24). Presutural dorsocentral bristles stout; meso- notum strongly arched Metapogon carinatus Wilcox — Presutural dorsocentral bristles absent; mesonotum not strongly arched Eucijrtopogon Curran 26(24). Face strongly inflated, extending greater than length of scape past eye margin when viewed from the side 27 — Face flat or but slightly convex 29 27(26). Dorsocentrals weak, hairlike Cyrtopogon Loew — Dorsocentrals bristlelike, prominent 28 28(27). Mystax composed of bristles; male with wing tip darkened and basal half of wing covered with white bloom . . . Coleomyia alticola James — Mystax composed of weak hairs; wings of both sexes hyaline Nannocyrtopogon aristatus ]ames 29(26). Hind tibia club-shaped, broadest near apex, as thick as or thicker than hind femur Holopogon Loew — Hind tibia not club-shaped but spindle- shaped or straight, broadest near middle, thinner than hind femur 30 30(29). Hairs of thorax branched .. Heteropogon Loew — Hairs of thorax straight or crinkled, not branched 31 31(30). Legs and tergites with greenish metallic re- flections Sintoria cazieri Wilcox — Legs and tergites without metallic reflections Wilcoxia painteri Wilcox Key to the Species of Utah Ablautus Loew Including Omninablautus Pritchard (Modified from Wilcox 1966c) 44 Great Basin Naturalist Vol. 47, No. 1 Figs. 6-17. Utah Asilidae: 6, male genitalia of Machimits occidentalis (Hine), ventral aspect; 7, male genitalia of Machimus caUidus (Williston), ventral aspect; 8, antenna ofOspriocenis abdominalis (Say); 9, antenna of Ospriocerus vallensis Martin- 10, male genitalia of Regfl.«/i/.s Wanton! Bromley, lateral aspect, E = epandrium; 11, male genitalia of Neomochtherus lepidns (Hine), lateral aspect, E = notched epandrium; 12, male genitalia of Lasiopo^on aldrichii Melander, lateral aspect; 13, surstyli of La slop o go n aldrichii Melander from below; 14, male genitalia of Lasiopogon monticola Melander, lateral aspect; 15, surstyli of Lasiopogon monticola Melander from below; 16, surstyli of Lasiopogon cinereus Cole from below; 17, male genitalia of Asilus auriannulatus (Hine), lateral aspect,' E = epan- drium. January 1987 Nelson: Utah Robber Flies 45 1. Mesonotum with black, shining spots on sides Omninahlaiitus nig.ronotum Wilcox — Mesonotum entirely pollinose 2 2(1). Face, frons, thorax, and legs without scalelike hairs ■^ — Face, frons, thorax, and legs with scalelike hairs 4 3(2). Frons golden brown pollinose, male with scale- like hairs of foretarsi black laterally and pale brown medially, hind tibia and femur black . . . mimiis Osten Sacken — Frons white pollinose, male with scalelike hairs of foretarsi all brown, apex of hind femur and middle of hind tibia reddish rufotibialis Back 4(2). Frons white or slightly yellowish pollinose, scalelike hairs above antennae on frons not lim- ited to margins of eyes flavipes Coquillett — Frons golden brown pollinose; scale hairs of frons limited to margins of eyes . coquilletti Wilcox Key to the Species of Utah CaUinicus Loew (Modified from Wilcox 1936a) 1. Femora black, central stripe of mesonotum reaching scutellum, presutural black spots ex- tending to the lateral margins .... pollenius Cole — Femora yellow, central stripe of mesonotum reaching scutellum, presutural black spots small and isolated from lateral margin by golden pol- len pictitarsis Bigot Key to the Species of Utah Comantella Curran (Modified from James 1937b) 1. Style one-third as long as antennal segment 3; venter black-haired, at least on anterior seg- ments 2 — Style one-half as long as antennal segment 3; venter with all hairs white pacifica Curran 2(1). Thoracic mane set on a well-defined black vitta; hairs of mystax black on entire length rotgeri James — Thoracic mane set on poorly defined black vitta; hairs of mystax with tips white faUei (Back) Key to the Species of Utah Cophiira Osten Sacken (Modified from Pritchard 1943) 1. Scutellum entirely pollinose, base of tibia with dark yellow band poUinosa Curran — Scutellum shining black, base of tibia without dark yellow band 2 2(1). Wings hyaline albosetosa Hine — Wings brownish 3 3(2). Scutellum clothed with short, stout, dark bris- tles brevicornis (Williston) — Scutellum clothed with long, thin, light hairs scitula (Williston) Key to the Species of Utah Cijriopogon Loew (Modified from Wilcox and Martin 1936) 1. Last segment of male foretarsus extremely flattened albifacies Johnson — Last segment of male foretarsus not flattened 2 2(1). Scutellum convex, mostly shining; face usu- ally strongly gibbous; antennae situated at about three-fourths height of head; more densely pilose and less poUinose species .... 3 — Scutellum flattened, largely or entirely polli- nose; face not usually strongly gibbose; anten- nae situated at about one-half height of head; less pilose and more pollinose species 13 3(2). Antennal segment 3 yellowish red 4 — Antennal segment 3 black or dark brown .... 5 4(3). Abdomen with yellowish orange hairs, denser in male; pollinose fasciae of abdomen yellow- ish; mystax mostly golden; length 9-12 mm . aiiratus Cole — Abdomen with hairs light yellowish silver; pollinose fasciae of abdomen silver; mystax whitish yellow with much black; length 10- 15 mm pulcher Back 5(3). Abdomen with dense orange-yellow hairs on dorsum 6 — Abdomen with dense hairs (may be somewhat yellowish or black) limited to the lateral mar- gins "^ 6(5). Orange hairs of abdomen limited to segments 1-4 curtistyhis Curran — Orange hairs of abdomen on at least segments 1-5 dasyUoides Williston 7(5). Male with disc of broad black hairs on at least apical two segments of midtarsus; foretarsal segments 2-5 of male with a differentiated, dense, narrow fringe of silvery hairs 8 — Male without disc of black hairs on apical two segments of midtarsus; foretarsus of male without a differentiated fringe of silvery hairs 8(7). Long hairs of lateral margins of abdomen en- tirely yellowish white ... p/awsor Osten Sacken Long hairs of lateral margins of abdomen in part black willistoni Curran 9(7). Wing of male with apex black, apex of anal cell also black; wing of female darkened somewhat in same areas; pleura largely shining bimacula Walker Wing without black spots; pleura extensively pollinose ^^ 10(9). Tibiae and tarsi more or less reddish, at least below, rarely male with only underside of tarsi reddish ^1 Tibiae and tarsi either both black or with tib- iae all black and foretarsi yellow with white hairs ^^ 46 Great Basin Naturalist Vol. 47, No. 1 Figs, 18-29. Utah Asilidae, terminalia; 18, male genitalia of P/i//o/hc»,s flmonen.sJs (Williston) dorsal aspect E = epandnum, P - proctiger; 19, female genitalia of P/H7o;HC«,sflmonen,s/.s(Williston), lateral aspect; 20, male genitalia of Polacanthacomposita (Hine), dorsal aspect, E = epandrium. P = proctiger; 21, female genitalia of Polacantha composita (Hme), lateral aspect; 22, male genitalia oi Proctacanthella cacopiloga (Hine), lateral aspect E = epan- drmm; 23, female genitalia of Proctacanthella cacopiloga (Hine), lateral aspect; 24, male genitalia oiMachimus griseus Hme, lateralaspect, with left epandrium removed, E = epandrium unnotched, P = proctiger without ventral process 25, male genitalia oiMachimus adustus Martin, lateral aspect, with left epandrium removed E = epandrium P = proctiger with ventral process; 26, male genitalia of Procfflca»if/j».s nearno Martin, dorsal aspect, E = epandrium' P = proctiger; 27, female terminalia of Proctacanthus nearno Martin, lateral aspect; 28, male genitalia of Proctacanthus micans Schiner, dorsal aspect, E = epandrium, P = proctiger; 29, female terminalia of Proctacanthus micans Schiner lateral aspect. January 1987 Nelson: Utah Robber Flies 47 Figs. 30-33. Utah Asilidae, lateral aspect of head and thoim; 30, Sclcropo^on indistinctus (Bromley) showing hairs on katatergite (hvpopleuron); 31, Stenopofion inquinatus Loew showing bare katatergite (h\'popleuron); 32, Machimiis occidentalis (Hine) showing hairs on both katatergite and anatergite; 33, Promachus cdbifacics Williston showing hairs on katatergite and bare anatergite. 11(10). Mystax largely black; foretarsus of male yellowish jemezi Wilcox & Martin — Mystax largely white, particularly above (some females with a few black hairs above); foretarsus of male black montantis Loew 12(10). Foretarsus of male yellowish with white hairs; mystax of male white above ... rufotarsus Back — Foretarsus of male black with black hairs; mystax all black . . . stenofrons Wilcox & Martin 13(2). Pollinose fasciae of abdominal segment 1 en- tire or nearly so l^i — PoUinosity of abdominal segment 1 limited to patches near lateral margins, not extending medially across segment 16 14(13). Tibiae and femora reddish below; mystax black except for a few central, white hairs . . profusus Osten Sacken — Tibiae and femora black, midtibia sometimes reddish in male; mystax white above, black below 15 15(14). PoUinosity of abdominal segments narrowly interrupted along dorsal midline thompsoni Cole — PoUinosity of abdominal segments entire but with central spot on several segments lacking pollen ablautoides Melander 16(13). Scutellar hairs in large part white; pollinose fasciae of abdominal segments extending anteriorly along lateral margins idahoensis Wilcox 6f Martin — Scutellar hairs all black, pollinose fasciae of abdominal segments not extending forward . banksi Wilcox & Martin Key to the Species of Utah Dioctria Meigen (Modified from Adisoemarto and Wood 1975) 1. Pleuron with golden pollinose band extending uninterrupted from between base of wing and humeral callus to coxa vera Back — Pleuron with discontinuous pollinose band, broadly interrupted on anterior margin of meso- pleuron; interruption as wide as high 2 2(1). PoUinosity of mesopleuron restricted to and mostly covered by haired area near prothoracic spiracle ptisio Osten Sacken — PoUinosity of mesopleuron extending from prothoracic spiracle to base of wing henshawi Johnson Key to the Species of Utah Eucyrtopogon Curran The genus Eucyrtopogon Curran occurs in Utah with possibly as many as four or five species represented. The Curran (1923a) key easily distinguishes one species, E. comantis Curran, by the presence of a medial crest of white hairs on the mesonotum of the males. The other representatives of this genus in the state do not key out well. There are only eight 48 Great Basin Naturalist Vol. 47, No. 1 Figs. 34-46. Utah Asilidae, right wing: 34, Efferia aestuans (Linnaeus); 35, Efferia albibarhis (Macquart)- 36 Ejjeria apache Wilcox; 37, Efferia benedicti (Bromley); 38, Efferia costalis (Williston); 39, Efferia pernicus Coquillett- 40, Cyrtopogon willistoni Curran; 41, Efferia tucsoni Wilcox; 42, Promachus albifacies Williston; 43 Machimus occidentahs (Hine); 44, Efferia freivingi Wilcox; 45, Laphijstia tolandi Wilcox; 46, Leptogaster sp. from Clear Creek Raft River Mountains, Box Elder Co. , Utah. January 1987 Nelson: Utah Robber Flies 49 specimens before me from the collections at BYU, UU, SUSC, and CEU. These speci- mens seem to represent three distinct spe- cies. The specimens from USU have been sent to R. Lavigne at the University of Wyo- ming, as he is at present studying the genus. Seven of the USU specimens are labeled E. nebulo as determined by Bromley; other specimens are simply labeled Eucyrtopogon sp. Any determination of the species in Utah (except E. comantis) would be very tenuous on my part, due to the small number of speci- mens which I have seen; thus, determinations of Eucyrtopogon from Utah must await the work which Lavigne is preparing. Key to the Species of Utah Heteropogon Loew (Modified from Wilcox 1965) L Scutellum without marginal bristles; wing with dark spots on crossveins and furcations maculinervis James — Scutellum with marginal bristles; wings hyaline 2 2(1). Scutellum polished on hind margin, disc of scutellum pollinose; terminal abdominal seg- ments red stonei Wilcox — Scutellum entirely pollinose, sometimes thinly so, subshining black; terminal abdominal seg- ments black 3 3(2). Black bristles of mystax extending greater than one-third distance from oral margin to antennae 4 — Black bristles of mystax confined to oral margin extending less than one-third distance from oral margin to antennae ^ 4(3). Male with brush of black hairs in basal third of midtibia; hairs of mystax both black and white; scutellar bristles black senilis Bigot — Males without brush of black hairs on niidtibiae; hairs of mystax all white; scutellar bristles black species 1 5(3). Bristles of thorax and scutellum white, rarely one or two presutural black brisdes; bristles of mystax black and white, white bristles above . . martini Wilcox — Bristle of thorax both black and white; bristles of scutellum black; brisdes of mystax all black . . . arizonensis Wilcox Key to the Species of Utah Holopogon Loew (Modified from Martin 1959) 1. Mesonotum without presutural bristles laterally caesariatus Martin — Mesonotum with two or more presutural bris- tles laterally 2 2(1). Scutellum lacking pollen on posterior portion of disc near margin wilcoxi Martin — Scutellar disc pollinose (narrow margin may ap- pear to be lacking pollen) 3 3(2). Scutellar disc lacking hair currani Martin — Scutellar disc with a few to many hairs 4 4(3). Anterior mesonotal hairs sparse, erect, mostly brown mingusae Martin — Anterior mesonotal hairs dense, somewhat re- cumbent, white alhipihsus Curran Key to the Species of Utah Laphystia Loew (Modified from Wilcox 1960) 1. Scutellum with marginal bristles nearly as strong as lateral bristles of mesonotum; femora mostly dark brown, apices yellowish tolandi Wilcox — Scutellum with marginal hairs weak and pro- cumbent or absent; femora usually concolorous . 2 2(1). Marginal scutellar hairs weak and procumbent; abdomen not reddish 3 — Marginal scutellar hairs absent; abdomen red- dish brown rubra Hull 3(2). Abdomen yellowish, fasciae on segments 3-5 one-third length of segments; femora of both sexes wholly reddish; pollen of abdominal fas- ciae white utahensis Wilcox — Abdomen brown, femora yellowish, pollen of abdominal fasciae yellow annulata Hull Key to the Species of Utah Lasiopogon Loew (Modified from Cole and Wilcox 1938) 1. Marginal scutellar bristles white alhidus Cole & Wilcox — Marginal scutellar bristles black 2 2(1). Surstyli of male genitalia one and one-third times as long as high in lateral view (Fig. 12); male genitalia wider than adjacent abdominal segment in dorsal view (Fig. 13); sternite 9 of female genitalia amber colored aldrichii Melander Surstyli of male about two or more times as long as high in lateral view (Fig. 14), male genitalia narrower than abdomen in dorsal view; sternite 9 of female genitalia dark brown or black 3 3(2). Surstyli of male covered with ash-colored pol- len; surstyli without tooth on ventral margin before base (Fig. 16) (Note: male genitalia may be rotated 180 degrees) cinereus Cole Surstyli of male shining black or brown, surstyli with prominent tooth on ventral margin near base (Fig. 15) monticola Melander Key to the Species of Utah Nicocles Jaennicke (Modified from Wilcox 1946) 50 Great Basin Naturalist Vol. 47, No. 1 Figs 47-56. Utah Asilidae, lateral aspect of male terminalia and legs: 47, male terminalia of Efferia utahensis (Bromley); 48, male terminalia oi Efferia frewingi Wilcox; 49, male terminalia otEfferia mortensoni Wilcox; 50 male termmalia of Efferia tucsoni Wilcox; 51, male terminalia of Efferia bicolor (Bellardi); 52, male terminalia of Efferia MibarbisiMacquRrt)- 53, male terminalia of Efferia zonata (Hine); 54, foretihia and basitarsus of Diogmites grossus Bromley B - basitarsus, T = tibia; 55, foretibia and basitarsus of Cophura scitiila Williston, B = basitarsus T = tibia 56, middle leg of Callinicus pollenius (Cole), T = tibia. January 1987 Nelson: Utah Robber Flies 51 L Abdominal segments 3-7 of male and 4-6 of fe- male red, silver fasciae covering entire dorsnm oi male segments 5-6 ahdominalis Williston — All abdominal segments of male and female black; silver fasciae of male covering entire dorsnm of segment 6 and basal portion of segment 5 utcihcnsis Banks Key to the Species of Utah Ospriocems Loew (Modified from Martin 1968) 1. Abdominal segments entirely black minos Osten Sacken — Abdominal segments in part reddish, or brown pollinose ^ 2(1). Abdominal segments brown pollinose, tan in ground color lon^tihts (Loew) — Abdominal segments in part red, not pollinose . 3 3(2). Tip of flagellum with notch containing small in- conspicuous spine (Fig. 8) ahdominalis (Say) — Tip of flagellum produced as apical segment (Fig. 9) vallensis Martin Key to the Species of Utah Scleropogon Loew (Modified from Wilcox 1971) 1. Cells rj and nij with long petioles subequal to length of rm crossvein picticornis Loew — Cells r, and m, either open or with one or other having a short petiole 2 2(1). Antennal segment 3 one and three-fourth times as long as segments 1-2; abdomen slender, gray pollinose; wings tinged with brown duncani (Bromley) — Antennal segment 3 at most one and one-half times as long as segments 1-2; abdomen stock- ier; wings hyaline 3 3(2). Hypopleuron with bristles, cell nij closed and usually short petiolate ^ — Hypopleuron with hairs, cell nij broadly open . . 5 4(3). Abdomen stout, apex of wings reaching to ter- gite 6; ground color of most of abdomen tan; length 15-19 mm coyote (Bromley) — Abdomen elongate, apex of wings not reaching to tergite 6 but covering base of tergite 5; ground color of abdomen dark brown with bases and apices of segments tan; length 19-26 mm indistinctus (Bromley) 5(3). Abdomen black, narrow posterior and lateral margins of tergites tan; densely pollinose neglectus (Bromley) — Abdomen reddish brown, black laterally on basal segments; thinly pollinose bradleyi (Bromley) Key to the Species of Utah Stenopogon Loew (Modified from Wilcox 1971) 1. Gibbosity of face extending about one-half to three-fourths distance from oral margin to an- tennae (Fig. 3); fore coxae with numerous bris- tles 2 — Gibbosity extending atjout five-sixths to seven- eighths distance from oral margin to antennae (Fig. 2); fore coxae with numerous long hairs ... 3 2(1). Gibbosity weak, face not strongly inflated; shiny black triangle between mystax and antennae ab- sent; small, length 9-10 mm . . utahensis Bromley — Gibbosity strong, face strongly inflated; shiny black triangle between mystax present; large, length 20-37 mm inquinatus Loew 3(1). Abdomen densely pollinose; long hairs on inner arms of hypandrium continuing across base . . . martini Bromley — Abdomen subshining black; long hairs on inner arms of hypandrium interrupted medially 4 4(3). Hind tibiae with indistinct reddish area at least near apex; mystax yellowish engelhardti Bromley — Hind tibiae all reddish or yellowish, mystax red- dish rufibarhis Bromley Key to the Utah Stichopogon Loew (Modified from Wilcox 1936b) 1. Scutellum with marginal hairs or bristles; pollen of abdomen golden and brown; length 3-5 mm fragilis Back — Scutellum lacking marginal hairs or bristles; pol- len of abdomen silver; length greater than 6 mm 2 2(1). Tergite 4 mostly silvery pollinose sometimes with medial portion of apex lacking pollen .... trifasciattis Say — Tergite 4 with black band covering basal third . salinus (Melander) Key to the Genera of Utah Laphriinae 1. Postmetacoxal area forming a sclerotized arch when viewed from below; flagellum bearing ei- ther a short dorsal bristle or terminal style 2 — Postmetacoxal area entirely membranous; fla- gellum without dorsal bristle or terminal style, apical pit may contain a short bristle 3 2(1). Coloration and pile resembling a bumblebee; anatergite bare; length over 25 mm Dasylechia atrox (WiUiston) Body quite bare, not resembling a bumblebee; anatergite haired or with bristles; length less than 20 mm Atomosia mucida Osten Sacken 3(1). Proboscis compressed laterally; some species resembling bumblebees in pile and coloration Laphria Meigen ^Wilcox has determined specimens as being either S. eng.elhardti or S. rufibarhis from the same locahties which do not agree with the final couplet of this key. It may be that the characters used in this key (adapted from Wilcox 1971) are not dependable in separating Utah specimens of these two species. 52 Great Basin Naturalist Vol. 47, No. 1 ;i-:^ ♦ Ablautus cog 11 illetti AAblautus flflu i pes ±M BOmninablautus n 57 qronotum 1 --WW '^$ipP'f^:i v,^^-.j?i.. ■;i ?. > r~\ 1-; V- 1 1 41- .^ ^;^W;::::::- :;:: A " ^fe-- 1 ■ ^^1' (^;-o;»f--. ;■ 0 Asilus formosus A Astlus vescus ■V?-;-:. Figs. 57-60. Utah Asilidae, distribution: 57, Ablautus coquilletti, Ablautus Jlavipes, and Omninablautus nigrono- tum ■ 58, Ablautus mimus and Ablautus rufotibialis ■ 59, Asi/us auriannulatus ■ 60, Asilus formosus and Asi/us uescus . January 1987 Nelson: Utah Robber Flies 53 — Proboscis flattened dorsoventrally; abdomen mostly bare and reddish orange Cerotainiops ahdominalis (Brown) Key to the Genera and Species of Utah AsiHnae (Modified from Wood 1981) L Anatergite (metanotal callus) bare (Fig. 33) .. 2 — Anatergite (metanotal callus) with bristles or hairs (Fig. 32) 9 2(1). R4 with recurrent vein; recurrent branch (stump vein) sometimes short (Fig. 35), end- ing in cell r,+3 or extending basally and joining R,,3(Fig.42) 3 — R4 without recurrent vein (Fig. 43) 7 3(2). Cell rj narrow, apical half of R5 subparallel with R4 (Figs. 35-39) Effeha Coquillett — Cell r4 broad, apical half of R5 diverging strongly from R4 (Fig. 42) 4 4(3). Claws acute; abdomen elongate 6 — Claws blunt; abdomen stout 5 5(4). Lower face inflated; hind femur club-shaped, with row of bristles below near apex; Utah specimens have black pile on thorax Mallophora fautrix Osten Sacken — Lower face not greatly inflated; hind femur spindle-shaped and without bristles below near apex; pile of thorax in Utah specimens mostly gray and/or yellow . . . Megaphonis Bigot 6(4). Recurrent branch (stump vein) short (similar to Efferia), not reaching R2+:3 Triorla interrupta Macquart — Recurrent vein extending to and connecting with R2+3 Prornachus Loew 7(2). R5 reaching wing margin anterior to apex of wing Proctacanthus Macquart — R5 reaching wing margin posterior to apex of wing 8 8(7). Epandria of male black and elongate, longer than tergite 6; terminalia of females lacking strong bristles Regasilus hlantoni Curran — Epandria of male red and short, subequal to length of tergite 6 (Fig. 22); terminalia of fe- male bearing strong bristles (Fig. 23) Proctacanthella cacopiloga Bromley 9(1). Occipital bristles long and fine, distal third strongly bent anteriad at nearly a 90 degree angle (Fig. 5) . . . Neoitamiis hrevicomus (Hine) — Occipital bristles stout, not bent forward at a sharp angle, but may bend forward gradually throughout length 10 10(9). Epandria of male arching to enclose an open space when viewed from above (Fig. 18); ter- minalia of female bearing several pairs of stout bristles (Fig. 19) Philonicus Loew — Epandria of male not arching to enclose an open space when viewed from above, but touching along most of dorsomedial margin (Fig. 20); terminalia of female lacking stout bristles (Fig. 21) H 1 1(10). Length of antennal style at least one and one- third length of antennal segment 3; inner sur- face of epandrium of male with patch of erect spines Polacantha Martin — Length of antennal style of antenna shorter than or subequal to length of antennal seg- ment 3; inner surface of epandrium lacking erect spines 12 12(11). Epandria ofmale notched near apex (Fig. 11) Neomochtheriis Osten Sacken — Epandria ofmale not notched near apex (Fig. 24) 13 13(12). Style about one-fourth length of antennal seg- ment 3; bristles of tergites 2 and 3 short and recumbent Negasilus Curran — Style longer than one-fourth length of anten- nal segment 3; bristles of tergites 2 and 3 longer and erect 14 14(13). Epandria of males pointed and directed up- ward at apex (Fig. 17), apices diverging .... Asilus aurianntdattis Hine — Epandria of males not pointed and not di- rected upward at apex, apices converging . . . . . Machimiis Loew, Asilus vescus Hine, and A . formosiis Hine Key to the Species of Utah Efferia Coquillett (Modified from Wilcox 1966a) 1. Three submarginal cells in wings (no vein ending in a submarginal cell, but continuing to meet Ro), (Fig. 39)(Anomala group) 2 — Two submarginal cells in wings, 'stump' vein present and ending in first submarginal cell . . 3 2(1). Hairs on abdominal sternites much longer than antennal segments 1-2 combined pernicus Coquillett — Hairs on abdominal sternites subequal to an- tennal segment 1 in length davlsi Wilcox 3(1). R4+5 forking before apex of discal cell (Figs 37, 44) 4 B^^5 forking at or beyond apex of discal cell (Figs. 34-36, 38, 41) H 4(3). Mesonotum anteriorly with bristles or hairs at least as long as antennal segments 1-2 com- bined; color ofmale abdominal segments 2-5 alternating black and white; lacking long parted hairs; segment 6-7 white pollinose; ovipositor pointed and split at tip when viewed from above (Pogonias group) 5 Mesonotum anteriorly with bristles and hairs shorter than antennal segments 1-2 com- bined; color ofmale abdominal segments gray or white pollinose, often with white parted hairs; ovipositor rounded at tip, not spht when viewed from above (Staminea group) . . 7 54 Great Basin Naturalist Vol. 47, No. 1 'il:{y-p' A Atomosia mucida , 'a ' j f^- # Cerotainiops abdominal is -'x?'^^-S 61 # Bleehare£iurii sonorenslj A Caninicus pictitarsis ■ Callinicus pollenius ym& --trr-'*' -.—■ ^-,-^.--r^ -'^k— "- 1-^ . _■ '^^-l^'^^ ,.?'i'^' V .-'-'-i,^ -•■■e-'S"- ' -'■.■■|'' j|- '-. 1 yA-,;^%7;fr--^ • A "*,*;r ■■;.:// 0 Cophura scitula y Cophura albosetosa ■ Cophiirri, brevicornis A Cophura pollinosa .i*?^i^|^v'^:;^^ Figs. 61-64. Utah Asilidae, distribution: 61, Atomosia mucida and Cerotainiops ahdominalis ■ 62 Blepharepium sonorensis, Callinicus pictitarsis, and Callinicus pollenius; 63, Coleomi/ia alticola , Comantella pacifica , and Cojnan- tellajallei;64, Cophura scitula, Cophura albosetosa, Cophura brevicornis. and Cophura pollinosa. January 1987 Nelson: Utah Robber Flies 55 5(4). Lower forceps of male with apical lobes form- ing an acute angle when viewed laterally (Fig. 47); scutellar bristles and hairs white (some- times one black); mysta.\ with at most four black bristles; females with fore and middle tibiae black, sometimes brownish dorsally near bases titahensis (Bromley) — Lower forceps of male with apical lobes meet- ing basally as a broad U or with a flattened area between them at base (Figs. 48-49); scutellum with black bristles and white hairs or white bristles and black hairs, bristles and hairs not all white; mystax with at least eight black hairs or bristles along oral margin; fe- males usually with fore and middle tibiae brown, if black then scutellar bristles black . . 6 6(5). Lower forceps of male with apical lobes join- ing in a broad, evenly curved U when viewed laterally (Fig. 48); scutellar bristles usually black (at least in part), hairs of scutellum usu- ally white; common frewingi Wilcox — Lower forceps of male with a broad relatively flat area between the apical lobes (Fig. 49); scutellar bristles white (at most one black), hairs of scutellum all black; rare, single speci- men from St. George mortensoni Wilcox 7(4). Mystax yellow, pollen of foce yellow (slightly yellow in female but contrasting with white hairs of postgena) staminea (Williston) — Mystax and pollen efface silvery white, hairs of mystax and postgena both white 8 8(7). Sternite 8 of male produced medially at apex; female with R4^5 forking at or before middle of the distance between rm and apex of discal cell 9 — Sternite 8 of male not produced medially, straight when viewed from below; female with R4+5 forking beyond middle of distance between rm and apex of discal cell 10 9(8). Anterior mesonotal crest shorter than anten- nal segment 1; sparse, white parted hairs on abdominal segments 2-4; abdomen grayish pollinose henedicti (Bromley) — Anterior mesonotal crest subequal to length of antennal segments 1 and 2; long, white parted hairs on abdominal segments 2-5 and short parted on 6-7; abdomen silvery-white pollinose basini Wilcox 10(8). Fringe of hairs on surstyli of male white; white parted abdominal hairs long and dense on segments 1-7 of male; female indistin- guishable from that oicana .... deserti Wilcox — Fringe of hairs on lower forceps of male black in part; white parted abdominal hairs long on segments 1-4, short on segments 5-7, sparse on all; female indistinguishable from that of deserti cana (Hine) 11(3). R5 reaching costa before apex of wing (Figs. 35-38, 41) 12 — R5 reaching costa after apex of wing (Fig. 34) aestuans (Linnaeus) 12(11). Anterior part of mesonotum compressed lat- erally; acrostical crest of long hairs or bristles present (Carinata group) 13 — Anterior part of mesonotum not compressed laterally; crest, if present, extends onto dor- socentral row as well as acrostical row 15 13(12). Abdomen of male lacking long, white parted hairs; black of segments 2-4 extensive; mesonotal crest short, subec}ual to antennal segment 1; ovipositor greater than 4 mm in length wiUistoni (Hine) — Abdomen of male with long, white parted hairs; black of segment 2-4 limited (at most) to hind margins; mesonotal crest subequal to length of antennal segments 1-3; ovipositor usually less than 4 mm in length (if longer, then mesonotal crest long) 14 14(13). Abdominal segment 7 of male with mostly black hairs; ovipositor about 4 mm long .... subcuprea (Schaeffer) — Abdominal segment 7 of male with mostly white hairs; ovipositor 3.5 mm or less in length (wing. Fig. 38) costalis (Williston) 15(12). Mesonotum anteriorly with numerous erect hairs or bristles as long as antennal segments 1-3; marginal bristles of scutellum numerous; bristles of tarsi mostly white (Arida group) .. 16 — Mesonotum anteriorly with bristles and hairs shorter than antennal segments 1-2; fewer than ten marginal scutellar bristles 18 16(15). Mystax mostly white, 1-8 black hairs below and laterally; discal hairs of scutellum mostly white (especially in female); bristles and hairs of postalar callus mostly white (or a few of weaker bristles and hairs black) . apache Wilcox — Mystax with dense black hairs below and lat- erally in male, lateral black hairs sparser in female but more than eight present; white hairs of scutellum limited to base and sides (or absent); bristles and hairs of postalar callus mostly black (with at least one strong white bristle) ^'^ 17(16). Foretibia mostly black, somewhat lighter basally; scutellar bristles black in male, white in female arida (Williston) Foretibia reddish basally and black apically; scutellar bristles white (only male seen; may simply be variant oi arida ) . subarida (Bromley) 18(15). Males with prominent, ventral tubercles on abdominal segments 4-7 (Fig. 50), slender species (Tuberculata group) Males without prominent tubercles on ab- dominal segments (Fig. 52); usually larger, stouter species (Albibarbis group) 19(18). Male terminalia and tubercles reddish; fe- male abdominal segment 7 and base of ovipos- itor reddish; abdominal tergites largely white haired, some hairs of tergite 7 black tucsoni Wilcox 19 20 56 Great Basin Naturalist Vol. 47, No. 1 4.J f-:^. # Cyrtopogon bimacula A Cyrtopogon curti stylus ■ Cyrtopogon dasyHoides 66 9 Cyrtopogon idahoens A Cyrtopogon Jemezi Figs. 65-68. Utah Asilidae, distribution: 65, Cyrtopogon ablaiifoidcs , Cyrtopogon auratus , and Cyrtopogon banksi; 66, Cyrtopogon himacula, Cyrtopogon curtistylns , and Cyrtopogon dasylloides ; 67 , Cyrtopogon idahoensis, Cyrtopogon jemezi , and Cyrtopogon albifacies ; 68, Cyrtopogon montanus . January 1987 Nelson: Utah Robber Flies 57 — Male terminalia and tubercles black; female abdominal segment 7 and base of ovipositor black; abdominal tergites broadly black haired producta (Hinc) 20(18). Male terminalia black; surstyli with ventral tooth near apex (Fig. 51); marginal scutellar bristles black with discal hairs long and white bicolor Bellardi — Male terminalia reddish; surstyli without ventral tooth near apex (Figs. 52, 53); scutel- lum with either black bristles and some short black hairs or with bristles and hairs both white 21 21(20). Mystax all white; transverse black (or brown- ish) bands of abdomen interrupted by longitu- dinal lighter stripe; length of ovipositor sub- equal to length of abdominal segments 6-7; male genitalia as in Fig. 52 alhibarhis (Macquart) — Mystax black and white; transverse black bands of abdomen uninterrupted; length of ovipositor greater than length of abdominal segments 6-7; male genitalia as in Fig. 53 . . zonata (Hine) Key to the Species of Utah Machimus Loew Including Asilus formosiis Hine and Asilus vescus Hine (Modified from Hine 1909 and Martin 1975) 1. Hind femur longitudinally yellowish brown on ventral surface and black on dorsal surface 2 — Hind femur with yellowish brown confined to apex, or hind femora entirely black 4 2(1). Wing with some dark coloration; especially near apex 3 — Wing entirely hyaline Asilus fonnosits Hine 3(2). Wing with dark spots in medial cells; distal fourth of wing with dark coloration isolated from veins except at extreme tips; proctiger without ventral process near apex griseus (Hine) — Wing without dark spots in medial cells, distal fourth of wing with faint dark wash reaching veins before apex; proctiger with ventral process near apex (Fig. 25) adustns Martin 4(1). Sternite 8 of male produced apically and bearing tuft of longer hairs on apex of produced area (Fig. 6) 5 — Sternite 8 of male not produced apically, hairs of uniform length across posterior margin (Fig. 7) . 6 5(4). Proctiger with two processes near its attachment to abdomen; medial areas of tergites covered with brown pollen sestertius Martin — Proctiger lacking processes; medial areas of ter- gites covered with dense, silvery pollen occidcntalis (Hine) 6(4). Small, less than 11 mm in total length; male terminalia reddish brown Asilus vescus Hine — Larger, greater than 12 mm in total length; male terminalia black or dark brown 7 7(6). Pollen of abdomen golden; color of incisures not contrasting greatly with color of remainder of each segment paropus (Walker) — Pollen of abdomen silvery; incisures yellowish, contrasting with the black remainder of each segment callidus (Williston) Key to the Species of Utah Megaphorus Bigot (Modified from Cole and Pritchard 1964) 1. Costa ending near wing tip 2 — Costa continuing around wing tip to hind margin 4 2(1). Cell rj open pulcher (Pritchard) — Cell r, closed, usually petiolate 3 3(2). Wing veins brown tvillistoni (Cole)'* — Wing veins yellow guildiana (Williston)'' 4(1). Pile of thorax and abdomen white, wings yellow- ish; length 10 mm pallidus (Johnson) — Pile of thorax and abdomen bright yellow, wings brownish; length 12-14 mm . . fnistra (Pritchard) Key to the Species of Utah Negasihis Curran 1. Margin of scutellum with bristles . . . mesae (Tucker) — Margin of scutellum lacking bristles ... belliCunan Key to the Species of Utah NeomochtJierus Osten Sacken 1. Face white, disc of scutellum lacking long, white hairs hypopygialis (Shaeffer) — Face brown; disc of scutellum with long, white hairs 2 2(1). Wings of male with brown color concentrated in area near middle of anterior half of wing; anal lobe of male hyaline lepidus (Hine) — Wings of male with brown color evenly dis- tributed throughout; anal lobe of male tinged with brown alhicornis (Hine) Key to the Species of Utah Philonicus Loew 1. Wing smoky; legs dark red . . arizonensis (Williston)' — Wing clear; legs pale reddish . limpidipennis (Hine) Key to the Species of Utah Proctacanthus Macquart (Modified from Hine 1911) ^With regard to M. willistnni and M. nuildiana. Cole and Pritchard state. 'Some populations [oi willl'iUmi]. particularly in Utah, tend to blend with Ruildiam." After examining the specimens of these species found in the state, 1 found the key lead most comfortably to tvillistoni. 'Specimens of both species have been identified by Bromley and Wilcox as occurring scattered throughout the state. Using the above key derived from Hine (19()9) and Bromley (1934), I found that specimens from Utah seem to run best to arizonensis . 58 Great Basin Naturalist Vol. 47, No. 1 W^ • Cyr topogon plausor A Cyrtopogon profusus 69 '•y% # Cyrtopogon pulcher A Cyrtopogon rufotarsus H Cyrtopogon stenofrons • Cyrtopogon wilHstoni A Cyrtopogon thompsoni • •; :•#. •^•. Figs. 69-72. Utah Asilidae, distribution: 69, Cyrtopogon plausor and Ci/rtopogon profusus- 70, Cyrtopogon pulcher, Cyrtopogon rufotarsus, and Cyrtopogon stenofrons; 71, Cyrtopogon ti)i//i.stont and Cyrtopogon thompsoni; 72, Uioctria vera , Dioctria henshawi , and Dioctria pusio . January 1987 Nelson: Utah Robber Flies 59 1. Body with ground color reddish orange Iiinci Bromley — Body with ground color black and orange 2 2. Wings with uniform brownish tinge milberti Macquart — Wings clear or with brown concentrated near veins 3 3(2). Epandria of male genitalia curving outward and then back to enclose a space between tips and proctiger when viewed from above (Fig. 26); terminal keellike sternite of female lacking strong spines ventrally (Fig. 27); circlet of spines present dorsally nearno Martin — Epandria not enclosing a space, but straight and compact against proctiger (Fig. 28); terminalia of female with ventral keellike projection covered with stout spines in addition to dorsal circlet of spines (Fig. 29) micans Schiner Key to the Species of Utah Promachiis Loew (Modified from Hine 1911) 1. First submarginal cell with dark, distinct gray cloud 2 — First submarginal cell clear or with very faint, narrow gray line; black areas of abdomen with few to many white hairs near lateral and poste- rior margins of segments aldrichii Hine 2(1). Male genitalia without silvery hairs above; tibiae yellow in contrast to black femora . . sackeni Hine — Male genitalia with silvery hairs above; tibiae and femora more or less concolorous, not con- trasting greatly 3 3(2). Mystax white, sometimes slightly yellow; thorax gray pollinose; male abdominal tergite 3 without lateral patch of dense black hairs; light hairs of abdomen whitish gray albifacies Williston — Mystax yellowish; thorax brownish yellow polli- nose; male abdominal tergite 3 with lateral patch of dense black hairs; light hairs of abdomen yel- lowish dimidiatus Hine Synopsis OF Species Subfamily Dasypogoninae Ablautus coquilletti Wilcox 1935: 226 [Holotype: male, Los Angeles Co., California in USNM]. Utah distribution: Washington Co. : Leeds Cyn. , Santa Clara. 4 May-2 June. '^Authors including M. T. James, J. Wilcox, and S. W. Bromley have identified these three species as occurring in Utah. I have difficulty, how- ever, in seeing a distinct brownish tinge of the wings of P. milberti, making the male specimens determined by these people run to P. micans in Hine s key (1911). Females labelled P milberti lack the spines on the terminal keellike stemites. The dorsal circlet of spines of P. milberti is composed of several rows (2-4) of spines, while those of P. micans and P. nearno are reduced to a single row of stouter spines. These observations were made without examining types but by comparing specimens in the USU collection which had previously been identified by the above authors. Ablautus flavipes Coquillett 1904: 178 [Types: Three males and two females, Los Angeles and San Diego counties, California in USNM]. Utah distribution: Juab Co.: Topaz Mtn.; Tooele Co.: Dugway Proving Ground. 26April-20June. Ablautus mimus Osten Sacken 1877: 290 [Holotype: male, Crafton near San Bernardino, California, March in MCZ]. Utah distribution: Carbon Co.: Woodhill; Emery Co.: Elmo; Kane Co.: Kanab; Tooele Co.: Cedar Mtns.; Utah Co.: Alpine, Provo, Spanish Fork, Vineyard (now Geneva Steel), west side Utah Lake. 6 April-4 July. Ablautus rufotibialis Back 1909: 182 [Holo- type: female, Ysleta, Texas, 2 April 1902 in AESP]. Utah distribution: Grand Co.: Moab; Juab Co.: Topaz Mtn.; San Juan Co.: Comb Wash 32 mi SW Blanding; Tooele Co. : Dug- way Proving Ground. 17-22 April. Blepharepium sonorensis Papavero and Bernardi 1973: 175 [Holotype: Arizona, Palos Verdes, viii. 1949, in Museu Zoologia da Uni- versidade de Sao Paulo]. Utah distribution: Washington Co.: St. George, Coalpits Wash, Zion National Park. 5-18 August. Bohartia sp. Utah distribution: Rich Co.: Dry Basin. 4 August. Callinicus pictitarsis (Bigot) 1878: 411 [Holotype: California; in Bigot Collection]. Utah distribution: Washington Co.: Zion Na- tional Park. No dates on labels. Callinicus pollenius (Cole) in Cole and Lovett, 1919: 237 [Holotype: male. Hood River, Oregon, 24 September 1917; #491 in CAS]. Utah distribution: Cache Co.: Black- smith Fork Canyon; Rich Co.: Logan Canyon summit. 30 July-1 September. Coleomyia alticola James 1941: 37 [Holo- type: male. Science Lodge near Ward, Colo- rado, 24 July 1939, repository not listed], Utah distribution: Cache Co.: Beaver Moun- tain, Blacksmith Fork Canyon, Tony Grove; Rich Co.: Logan Canyon summit, Monte Cristo; Uintah Co.: Whiterocks. 6 June-14 August. Comantella fallei (Back) 1909: 278 [Lecto- type: male, Fort Collins, Colorado, 30 March 1900; in CSU]. Utah distribution: Carbon Co.:Sunnyside. 11-10-1936. Comantella pacifica Curran 1926: 311 [Holotype: Penticton, B.C., 4 April 1919, #2320 in CNC]. Utah distribution: Box Elder Co. : Wildcat Hills; Carbon Co. : Price Airport; 60 Great Basin Naturalist Vol. 47, No. 1 Eucyrtopogon comanti's Sf nVvPr^^ir ^^'i Asilidae, distribution: 73, Diofimites oj-osstts and Dicolonus sparsipilosum, 74, Eucyrtopogon mantis -md Eucyrtopogon spprJS, Effcna apache And Effehadavisi- 76, Efferiaalbibarbis. ^ h s January 1987 Nelson: Utah Robber Flies 61 Daggett Co.: Sheep Creek; Millard Co.: Kanosh; Tooele Co.: Cedar Mountains. 26 March-4 May. Comantella rofgeri James 1937b: 61 [Holo- type: male, Stollsteimer, Colorado, 6,500 ft, 29 October 1935, no repository listed]. Utah distribution: Iron Co.: Cedar City. 26 Octo- ber. Cophura albosetosa Hine 1908: 202 [Syn- types: two males and one female, Hope Mountains, B.C.; probably in OSU]. Utah distribution: Cache Co.: Green Canyon; We- ber Co. : Willard Peak. 21 July-13 August. Cophura brevicornis Williston 1883: 22 [Syntypes: Two specimens, sex not known, from Washington, in KU]. Utah distribution: Uintah Co. : Whiterocks Canyon; Washington Co.: Zion National Park; Wayne Co.: near Grover. 12 July-7 August. Cophura pollinosa Curran 1930: 10 [Holo- type: male, Kitt Peak, Rincon, Baboquivari Mountains, Arizona, 1-4 August 1916, 4,050 ft, in AMNH]. Utah distribution: Washington Co.: Santa Clara, Zion National Park. 30 May-27 July. Cophura scitula Williston 1883: 19 [Holo- type: sex not known, Washington Territory, in KU]. Utah distribution: Cache Co.: Green Canyon, Logan, Logan Canyon, Tony Grove, West Hodges Canyon; Grand Co.: Wilson Mesa; Rich Co.: Logan Canyon summit; San- pete Co. : Ephraim Canyon; Utah Co. : Ameri- can Fork Canyon, Aspen Grove, Emerald Lake. 10 July-23 September. Cyrtopogon ablautoides Melander 1923a: 111 [Syntypes: four males and six females, Mabton, Washington, 3 May 1911, in Me- lander Collection]. Utah distribution: Millard Co.: 15 mi N Delta. 31 May. Cyrtopogon albifacies Johnson 1942: 1 [Holotype: male. Glacier Lake, Mount Tim- panogos, Utah, 10,600 ft; August 1928, in BYU]. Utah distribution: Utah Co.: type lo- cality. July-August. Cyrtopogon auratus Cole in Cole and Lovett, 1919: 230 [Holotype: male, Mt. Rainier, Washington, White River Camp, 4 September 1932, in CAS]. Utah distribution: Cache Co.: Logan, Logan Canyon; Duchesne Co.: Mirror Lake; Rich Co.: Monte Cristo; Summit Co. : Trial Lake. 5 August-14 August. Cyrtopogon banksi Wilcox and Martin 1936: 79 [Holotype: male, Puyallup, Wash- ington; 3 June 1933, in CAS]. Utah distribu- tion: Cache Co.: Avon, Blacksmith Fork Canyon, Cold Spring-Mendon, Providence, Smithfield, Tony Grove, Twin Creek, Wellsville; Daggett Co.: Ashley National Forest, Elk Park; Grand Co.: La Sal Moun- tains; Juab Co.: Mount Nebo; Rich Co.: Gar- den City, Logan Canyon summit, Monte Cristo; Utah Co. : American Fork Canyon, As- pen Grove, Mt. Timpanogos, North Fork Provo Canyon; Wasatch Co.: Wolf Creek Pass. 12 June-14 August. Cyrtopogon bimacuhi (Walker) 1851: 102 [Syntypes: Four males and four females; 'North America,' in British Museum]. Utah distribution: Beaver Co.: Beaver; Duchesne Co. : Wolf Creek Pass; Garfield Co. : Boulder Mountain, Aquarius Plateau; Iron Co.: Cedar Breaks; San Juan Co.: La Sal; Sanpete Co.: Ephraim, Gunnison. 10 July-24 July. Cyrtopogon curtistylus Curran 1923a: 133 [Holotype: male. Cache Junction, Utah, 3 June 1912, inC. W. Johnson collection]. Utah distribution: Box Elder Co.: Brigham City, Willard; Cache Co. : Cache Junction, Beaver Creek, Logan, Logan Canyon, Sardine Canyon; Davis Co.: Bountiful; Rich Co.: Lo- gan Canyon summit; Utah Co. : Glacier Park, Timpanogos, 2 mi W Cascade Springs, Pump- house Hill. 2 July-3 August. Cyrtopogon dasylloides Williston 1883: 11 [Holotype: male, Washington Territory, in KU]. Utah distribution: Cache Co.: Black- smith Fork Canyon, Logan. 16 May-12 June. Cyrtopogon idahoensis Wilcox and Martin 1936: 82 [Holotype: male, Parma, Idaho, 13 May 1934, in CAS]. Utah distribution: Cache Co.: Blacksmith Fork Canyon, Cold Spring-Mendon, Logan, Mendon, Sardine Canyon; Garfield Co. : Aquarius Plateau; Rich Co.: Monte Cristo; San Juan Co.: Bear Ears; Utah Co. : Payson Canyon; Weber Co: 13 mi S Monte Cristo. 9 June-23 July. Cyrtopogon jemezi Wilcox and Martin 1936: 47 [Holotype: male, Valle Grande, Je- mez Mountains, New Mexico, 6 July 1930, in CAS]. Utah distribution: Grand Co.: Lake Oowah; Uintah Co.: Brownie Canyon. 10 June-22 July. Cyrtopogon montanus Loew 1874: 362 [Holotype: male. Sierra Nevada, in MCZ]. Utah distribution: Box Elder Co.: Willard Peak; Cache Co. : Card Canyon, Dry Canyon, Franklin Basin, Green Canyon, West Hodges Canyon, Hyrum, Logan, Mount Naomi, 62 Great Basin Naturalist Vol. 47, No. 1 # Efferia aestuans A Efferia deserti H Efferia pernicus { ~'-\.y'^'^^§00M'^0^ - '--,.^7,-:' #|f-i|'' *:^ 9 Efferia cana A Efferia bicolor # Efferia benedicti U'ns'^^ 1- -.--;■■•#: [i:*"^"* .1 T ^(^Tt:^K.,» ;, • -'- ^. iv^rV/ J <»i >* . ;«■ i .Vi-V/'/ • Efferia costal is 80 % ' 1 ^^g^VrJ"?^-, ^^^^ Asilidae distribution: 77, £/jfena aestuans, Efferia deserti, and E/jfena pernicus, 78, Efferta ana , Ei/ena bicolor , and E^ena fca.sini ; 79, Efferia benedicti ■ 80, Efferia costalis . January 1987 Nelson: Utah Robber Flies 63 Providence, Tony Grove, Wellsville Moun- tains; Daggett Co.: Summit Springs; Duch- esne Co.: Duchesne, Mirror Lake, Wolf Creek Pass, Yellowstone Ranger Station; Garfield Co.: Aquarius Plateau; Juab Co.: Mount Nebo Loop; Rich Co.: Logan Canyon summit; San Juan Co.: Blanding; Sevier Co.: Highway 4; Summit Co. : Bear River Ranger Station, Beaver Creek Ranger Station; Uintah Co.: Brownie Canyon, Brush Creek; Wash- ington Co.: Pine Valley Mountains. 12 May-15 July. Cyrtopogon plausor Osten Sacken 1877: 297 [Syntypes: four males and two females, no locality listed, in MCZ]. Utah distribution: Cache Co.: Cache Valley; Garfield Co.: Aquarius Plateau, Boulder Mountain; Grand Co.: La Sal Mountains; San Juan Co.: Bland- ing, Elk Ridge; Summit Co.: Bear River Ranger Station; Utah Co.: Aspen Grove; Wasatch Co. : Strawberry Valley; Washington Co.: Pine Valley, Zion National Park; Wayne Co.: Bicknell, Boulder Mountain, Hanksville; Weber Co. : Farr West. 4 June-10 August. Cyrtopogon profusus Osten Sacken 1877: 305 [Syntypes: male and female, Morino Val- ley, New Mexico, 1 July, in MCZ]. Utah dis- tribution: Grand Co. : La Sal Mountains; Utah Co. : Mount Timpanogos. 21 July-17 August. Cyrtopogon pulcher Back 1909: 274 [Holo- type: male. Palmer Lake, Colorado, 10 July, in USNM]. Utah distribution: Box Elder Co. : Devils Gate, Willard Basin; Cache Co.: Beaver Mountain, Blacksmith Fork Canyon, Dry Lake, Logan Canyon, Tony Grove; Daggett Co.: Deep Creek, Sheep Creek; Emery Co.: Green River; Garfield Co.: Boul- der Mountain; Rich Co. : Logan Canyon sum- mit; Summit Co.: Bear River Ranger Station; Utah Co.: Aspen Grove, Mount Timpanogos; Wasatch Co. : Daniels Canyon summit; Wash- ington Co.: Leeds. 22 May-14 August. Cyrtopogon rufotarsus Back 1909: 275 [Holotype: male, Gallatin Co., Montana, 8,000-9,000 ft, 9-11 July, in University of Massachusetts collection]. Utah distribution: Duchesne Co.: Mirror Lake, Uinta Moun- tains; Grand Co.: Geyser Pass; Kane Co.: Long Valley; Sanpete Co.: Ephraim Canyon; Summit Co. : Trial Lake. 14 June-13 August. Cyrtopogon stenofrons Wilcox and Martin 1936: 52 [Holotype: male. Grant Co., New Mexico, 24 June 1934, in CAS]. Utah distribu- tion: Cache Co.: Logan; Wayne Co.: Capitol Reef. 1 September-17 October. Cyrtopogon thompsoni Cole in Cole and Lovett, 1921: 255 [Syntypes: male and fe- male, Burns, Oregon, May 1919, in CAS]. Utah distribution: Box Elder Co. : Curlew Val- ley; Daggett Co.: Clay Basin; Utah Co.: Goshen Springs. 16 June. Cyrtopogon willistoni Curran 1922: 277 [Holotype: male, Chilcotin, British Colum- bia, 16 June 1920, in CNC]. Utah distribu- tion: Box Elder Co. : Devils Gate, Raft River Mtns., Willard Peak; Cache Co.: Franklin Basin, Logan, Logan Canyon, Mount Naomi, Providence, Sardine Canyon, Tony Grove, Wellsville; Carbon Co.: Carbon Airport; Davis Co.: Bountiful; Grand Co.: Geyser Pass, Lake Warner, La Sal Mountains, Min- ers Basin, Moab; Iron Co. : Parowan Canyon; Juab Co.: Trout Creek; Millard Co.: Kanosh, Oak Creek Canyon; Rich Co. : Bear Lake Val- ley, Garden City, Logan Canyon summit, Walton (Allen) Canyon; San Juan Co. : La Sal Mtns., Wilson Mesa; Uintah Co.: White- rocks; Wasatch Co.: Strawberry Valley; Washington Co.: Leeds, Pine Valley, Zion National Park; Weber Co. : Monte Cristo. 16 May-14 August. Dicolonus sparsipilosum Back 1909: 247 [Cotypes: Two males, Bozeman, Montana, in Univ. of Mass. and Montana State Univ.]. Utah distribution: Cache Co. : Franklin Basin, Tony Grove; Rich Co.: Logan Cyn. summit; Utah Co.: Provo Cyn.; Wasatch Co.: Straw- berry Valley. 1-17 July. Dioctria henshatvi Johnson 1918: 103 [Holotype: Yakima, Washington, 2 July 1882, in MCZ #10036]. Utah distribution: Cache Co.: Green Cyn., Spring Hollow; Rich Co.: Logan Cyn. summit, Walton (Allen) Cyn.; Summit Co.: 10 mi E Kamas; Utah Co.: Oquirrh Mtns., Provo; Washington Co.: Pine Valley, St. George; Weber Co.: Ogden. 20 July-5 September. Dioctria pusio Osten Sacken 1877: 288 [Holotype: Female, Sonoma Co., California, 4 July, in MCZ]. Utah distribution: Utah Co.: Castella. 22 August. Dioctria vera Back 1909: 256 [Holotype: Male, Monterrey Co., California, 2 July 1896, in AMNH]. Utah distribution: Cache Co. : Lo- gan; Duchesne Co.: Whiterocks; Garfield Co.: Boulder Mtn.; Grand Co.: Castleton; Juab Co.: Deep Creek Mtns. near Callao; Kane Co.: Mt. Carmel; Millard Co.: Kanosh 64 Great Basin Naturalist Vol. 47, No. 1 • Efferia frewinqi 81 .I.....*.....;.. */, >^^1 :--'_■ J, ,-':r'"-^;' mm 0 Efferia producta ^ Efferia mortensoni ■ Efferia arida ■,V"-.--. AA • eria subcuprea A Ef f eri a stami nea ■ Efferia sub a r i d a •..'Mr. 9 Efferia utahensis A Efferia tucsoni 84 vifm ^':^\ jj Figs. 81-84. Utah Asilidae, distribution: 81, Efferia f re wingi ; 82, Efferia producta , Efferia mortensoni , and Efferia arida; 83, Efferia subcuprea, Efferia staminea, Efferia subarida, and Efferia subpilosa; 84, Efferia utahensis and Efferia tucsoni . January 1987 Nelson: Utah Robber Flies 65 Cyn., Oak Cr. Cyn.; San Juan Co.: La Sal Mtns., Mill Cr.; Washington Co.: Deep Cr., Leeds, Pine Valley; Wayne Co.: Grover. L3 June-20 August. Diogmites grossus Bromley 1936: 236 [Holotype: Male, Lamar, ProwerCo., Colo- rado, 25 August 1925, in Bromley Collection]. Utah distribution: Box Elder Co.: Pilot Range, Promontory, Snowville; Cache Co.: Cornish, Dry Cyn., Hyrum, Logan, Provi- dence; Davis Co.: Clearfield; Duchesne Co.: Bluebell; Grand Co. : Moab; Juab Co. : Topaz Mtn.; Kane Co.: Kanab; Millard Co.: Delta, Flowell, Garrison, Holden; Salt Lake Co.: Magna, Midvale; Tooele Co.: Camelback, Little Granite Mtn., Skull Valley, Simpson Butte; Utah Co.: Alpine, Goshen, Hobble Cr., Lincoln Beach, Provo, Rock Cyn., Spanish Fork; Washington Co.: Leeds, St. George, Zion National Park; Weber Co. : Og- den. South Weber. 30July-ll September. Eucyrtopogon comantis Curran 1923a: 116 [Holotype: Male, Chilcotin, B.C., 29 April 1920, in CNC #565]. Utah distribution: Utah Co.: Aspen Grove, Emerald Lake, Glacier Lake, Mount Timpanogos. No dates with la- bels. Eucyrtopogon spp. Utah distribution: Cache Co.: Dry Cyn., Logan Cyn., Logan Peak, Twin Cr. ; Duchesne Co. : Forest Camp, Uintah Cyn., Uinta Mtns., Wolf Cr.; Iron Co.: Cedar City; Rich Co.: Logan Cyn. sum- mit; Tooele Co. : Vernon Cr. ; Utah Co. : Aspen Grove; Wasatch Co.: Soldier Summit; Weber Co.: Eden. Haplopogon utahensis Wilcox 1966d: 99-106 [Holotype: Male, 7 mi N St. George, Utah, Hwy 91, 1 June 1963, in CAS]. Utah distribution: Washington Co.: Washington. 1-8 June. Heteropogon arizonensis Wilcox 1941: 55 [Holotype: Male, White Mtns., Arizona, Sep- tember, in CAS]. Utah distribution: Millard Co.: Oak City. 6-25 June. Heteropogon maculinervis James 1937a: 12 [Holotype: Female, Masonville, Colorado, 4 Sep 1934, in CSU]. Utah distribution: Beaver Co. : 9 mi E Beaver; Box Elder Co. : Clear Cr. , Fielding; Cache Co.: Avon Cyn., Green Cyn., Providence, Twin Cr.; Daggett Co.: Pipe Cr.; Grand Co.: La Sal Mtns.; Iron Co.: Cedar City; Kane Co.: Zion — Chamberlain Ranch; Tooele Co.: Granite Mtn., Johnsons Pass; Uintah Co.: Little Mtn., Summit, Utah State Exp. Sta. ; Utah Co. : Payson Cyn. , West Cyn.; Wasatch Co.: Soldier Summit; Wash- ington Co.: Zion National Park; Weber Co.: Huntsville. 6 August— 4 September. Heteropogon martini Wilcox 1965: 207 [Holotvpe: Male, Montgomery Pass, Nevada, 6 July 1958, in Wilcox Collection in CAS]. Utah distribution: Box Elder Co.: Snowville; Cache Co.: Logan, Wellsville Cyn.; Daggett Co. : Sheep Cr. ; Davis Co. : Clearfield; Emery Co.: 4 air mi N Gilson Butte; Millard Co.: Fillmore, warm spring near Gandi; Utah Co.: Fairfield, west side Utah Lake, Lehi. 16 June-4 September. Heteropogon senilis (Bigot) 1878: 423 [Holotype: sex not known, California, in Bigot collection]. Utah distribution: Box Elder Co.: Lucin, 1 mi NE Mantua; Cache Co.: Card Cyn. , Green Cyn. , Logan Cyn. ; Daggett Co. : Palisade Park Camp; Iron Co.: Kanarraville, near Parowan; Millard Co.: Oak Cr. Cyn.; Utah Co. : American Fork. 16 June^ Septem- ber. Heteropogon stonei Wilcox 1965: 207-222 [Holotype: Male, Hualapai Mtns., Arizona, 6,000 ft, 4 June 1962, in CAS]. Utah distribu- tion: Beaver Co. : Beaver Cyn. No date given. Heteropogon species 1. Two specimens, undescribed. Utah distribution: Box Elder Co.: Tecoma Range — Copper Mtns.; Tooele Co. : Lofgreen. No dates on labels. Hodophylax basingeri Pritchard 1938: 130 [Holotype: Female, Quail Spring, San Bernardino Co., California, 5 October 1934, in Basinger collection]. Utah distribution: Washington Co. : St. George. No date on la- bel. Holopogon albipilosus Curran 1923b: 207 [Holotype: Male, Vernon, B.C., 5 August 1920, in CNC #569]. Utah distribution: Beaver Co.: Beaver, Greenville, 9 mi E Beaver; Box Elder Co.: Park Valley, Portage; Cache Co.: Ant Valley, Blacksmith Fork Cyn., Logan, Mendon; Duchesne Co.: Duch- esne, Fort Duchesne, Tabiona, Whiterocks; Garfield Co.: Panguitch; Grand Co.: Dead Horse Point, Green River, 378 river mile; Iron Co.: Paragonah, Parowan; Juab Co.: Nephi, Trout Cr.; Kane Co.: Kanab; Millard Co.: Oak City, Pahvant, Scipio; Morgan Co.: Devils Slide; Piute Co.: Circleville; Rich Co.: Laketown, North Eden, Walton (Allen) Cyn.; Salt Lake Co.: Bluffdale, Magna, Salt Lake City; Sanpete Co. : Indianola, Manti, Moroni; 66 Great Basin Naturalist Vol. 47, No. 1 . • ' ■■ i • '^ ~ ' i?' ' ■"' '''■ ■ ■]■■■. '■-■ s u" - rn '\':.%-^;--'- ;■.:, ■' .^ \-]l-i - ^ :■'■'. ' \-J/;-'_ y""S""^ ---:..-., ■■\'^' \'^f ..'/ • '•••.- ''■--. f '' • • Effer ' V ,. ■' ' '■■it^fl^M^f:^^'/''^ ';,^= ' %&m- mw" #Heteropoqon martini JHeteropoqon ari zonensi s ^Heteropoqon species * •-:^--'- ■, ; / '■'' ■? ?-{: -^'x-'f --- — ?■-■-, i -■ ^■ '• , ;■•■ " ■■"■ ./ir&. I ''' i ■'■^- " ,,,-:-Hr '■: y\ ' .■ / Figs. 85-88. Utah Asilidae, distribution: 85, Efferia ivillistoni; 86. Efferia zonata ■ 87, Haplopogon utahensis, Hodophylax basingeri, and Lestomyia sabulona; 88, Heteropogon martini, Heteropogon arizonensis, and Hetero- pogon species 1. January 1987 Nelson: Utah Robber Flies 67 Sevier Co. : Elsinore, Glenwood, Richfield; Summit Co.: Red Rock Cyn.; Tooele Co.: Camelback, Dugway Proving Grounds, Little Granite Mtns.; Uintah Co.: Hayden, La Point, Naples, Tridell, Vernal, Whiterocks; Utah Co.: Alpine Loop, Aspen Grove, Lehi, Lindon, North Fork Provo Cyn., Payson, Provo, Provo Cyn., Spring Lake, Springville; Wasatch Co.: Heber, Strawberry Valley; Washington Co.: Pine Valley; Wayne Co.: Cainville, Grover. 1 June-5 August. Holopogon caesariatus Martin 1959: 1-40 [Holotvpe: Male, Alpha, Long Valley, Idaho, 6 July 1934, in AMNH]. Utah distribution: Cache Co. : Rlacksmith Fork Cyn. 7 August. Holopogon currani Martin 1959: 17 [Holo- type: Male, Winona, Arizona, 21 July 1949, in AMNH]. Utah distribution: Daggett Co.: Manila; Washington Co.: Leeds Cyn., Zion National Park; Wavne Co.: Grover. 11-28 July. Holopogon mingusae Martin 1959: 21 [Holotype: Male, Mingus Mtn., Arizona, 3 July 1949, in AMNH]. Utah distribution: Garfield Co.: Aquarius Plateau, The Pass; Washington Co.: Zion National Park; Wayne Co.: Grover. 11 July-21 August. Holopogon wilcoxi Martin 1959: 33 [Holo- type: Male, San Carlos Lake, Arizona, May, in CAS]. Utah distribution: Reaver Co.: Reaver; Tooele Co.: South Camel Mtn. 13 July. Laphystia annulata Hull 1957: 72 [Holo- type: Male, near Navajo, Arizona, 11 July 1954, in Hull collection]. Utah distribution: Kane Co.: Coral Pink Sand Dunes, Mount Carmeljct. 14 July. Laphystia rubra Hull 1957: 74 [Holotype: Female, near Navajo, Arizona, 11 July 1954, in Hull collection]. Utah distribution: Emery Co.: Goblin Valley, 4 air mi N Gilson Rutte, Wild Horse Creek; Grand Co. : Green River, 366 river mile; San Juan Co. : Rluff, Lime Cr. 7 July-26 August. Laphystia tolandi Wilcox 1960: 344 [Holo- type: Male, Lahontan Reservoir, Churchill Co., Nevada, 13 June 1949, in CAS]. Utah distribution: Rox Elder Co.: Corinne, Loco- motive Springs, Tremonton; Cache Co.: Cor- nish; Juab Co.: Fish Springs, Topaz Mtn.; Millard Co.: Delta, Fillmore; Sevier Co.: Richfield; Tooele Co.: Camelback, Granite Mtn.; Utah Co.: Spanish Fork. 14 June-14 August. Laphystia utahensis Wilcox 1960: 345 [Holotype: Male, St. George, Utah, 12 mi NE Hwy 17, 23 May 1959, in CAS]. Utah distribu- tion: Washington Co.: 12 mi NE St. George (near Hurricane). 22-23 May. Lasiopogon alhidus Cole and Wilcox 1938: 25 [Holotype: Male, 8 mi E Kiona, Washing- ton, 23 April 1933, in CAS]. Utah distribu- tion: Emery Co.: Green River (Gunnison Rutte); Grand Co. : Moab. 7 May. Lasiopogon aldrichii Melander 1923b: 139 [Syntypes: Male and female, Moscow Mtn., Idaho, 29 June 1918, repository not listed]. Utah distribution: Cache Co.: Logan Cyn.; Duchesne Co.: Roosevelt; Grand Co.: La Sal Mtns.; Rich Co.: Monte Cristo; Uintah Co.: Rrush Cr., Whiterocks; Utah Co.: Mt. Tim- panogos; Washington Co.: Leeds, Pinto. 24 June-21 July. Lasiopogon cinereus Cole, in Cole and Lovett 1919: 229 [Holotype: Male, Hood River, Oregon, 24 September 1918, in CAS #476]. Utah distribution: Daggett Co.: Manila; Duchesne Co. ; Uintah Co. : Merkeley Park (near Vernal), Whiterocks; Utah Co.: Hobble Cr. 6 July-16 August. Lasiopogon monticola Melander 1923b: 142 [Syntypes: Males and females, Mt. Adams, Washington, 24 July 1921, no reposi- tory listed]. Utah distribution: Cache Co.: Green Cyn., Logan Cyn., Mt. Logan; Grand Co.: Moab, Wilson Mesa-La Sal Mtns.; Rich Co.: Logan Cyn. summit, Monte Cristo; Uin- tah Co.: Whiterocks; Weber Co.: Ogden. 26 May-9 July. Lestomyia sabulona Osten Sacken 1877: 292 [Syntypes: Male and female, Grafton, near San Rernardino, California, March, on dry gravelly soil, in MCZ]. Utah distribution Rox Elder Co. : Promontory Point; Cache Co. Logan; Juab Co.: Topaz Mtn.; Salt Lake Co. Salt Lake Citv; Tooele Co. : Dugway Proving Grounds, Skull Valley. 24 May-9 June. Metapogon carinatus Wilcox 1964: 193 [Holotype: Male, Whitewater, California, 13 January 1948, in CAS]. Utah distribution: Uintah Co.: Split Mtn. Gorge. Date uncer- tain, "55-28" (2-8-1955?). Myelaphus lobicornis Osten Sacken 1877: 287 [Holotype: Male, Snake River, Idaho, in MCZ]. Utah distribution: Cache Co.: Rlack- smith Fork Cyn., Green Cyn., Hyrum Dam, Logan. 17-22 June. 68 Great Basin Naturalist Vol. 47, No. 1 9 Heteropoqon macul inervis AHeteropogon senilis B Heteropoqon stonei Holopoqon albipilosus *" ; /^i. )'^'"l • S'^fe ?t ■ f 9 Holopogon currani A Holopogon caesariatus 91 '^M$l 'Wl^ .->''•■■ "Sv. Holopogon mingusae Holopogon wilcoxi 92 --,/'',i^^.'''^*$C'-' Figs. 89-92. Utah Asilidae, distribution: 89, Heteropogon 7naculinervis , Heteropogon senilis, and Heteropogon stonei; 90, Holopogon albipilosus; 91, Holopogon currani and Holopogon caesariatus ; 92, Holopogon mingusae and Holopogon wilcoxi . January 1987 Nelson: Utah Robber Flies 69 Nannocyrtopogon aristatus James 1942: 126 [Holotype: Male, Arboles, Colorado, 6,700 ft, 17 May 1939, inCSU]. Utah distribu- tion: Iron Co.: 5 mi E New Harmony; Wash- ington Co.: Leeds Cyn., Oak Grove. 23 May-6 June. Nicocles abdominalis Williston 1883: 17 [Holotype: Male, California, in KU]. Utah distribution: Washington Co.: Zion National Park. No date on label. Nicocles utahensis Banks 1920: 66 [Holo- type: Female, Eureka, Utah, 31 May, in MCZ]. Utah distribution: Cache Co.: Green Cyn., Hyrum, Logan, Logan Cyn., Sardine Cyn., USU; Emery Co.: Green River; Grand Co.: Moab; Juab Co.: Eureka; Salt Lake Co.: Little Mtn.; Utah Co. : Provo. 5 March-5 June. Omninablautus nigronotum (Wilcox) 1935: 1 [Holotype: Male, Prairie Hill, Grant Co., Oregon, in CAS]. Utah distribution: Box El- der Co. : Etna. 12 August. Ospriocerus abdominalis (Say) 1824: 375 [Holotype: Lost]. Utah distribution: Beaver Co.: Minersville; Box Elder Co.: Blue Cr., Collinston, Mantua, Promontory, Snowville; Cache Co.: Beaver Mtn., Cornish, Clarkston, Hyrum, Lewiston, Logan, Mendon, Provi- dence, Smithfield; Daggett Co.: Douglas Di- nosaur Quarry, Flaming Gorge; Davis Co.: Farmington; Duchesne Co.: Monarch, Mountain Home, Myton; Emery Co.: 2 mi E Gilson Butte, 9 air mi E Castledale, Sinbad Country, Wild Horse Cr. north of Goblin Val- ley, Woodside; Grand Co.: Castleton, Moab; Iron Co.: Cedar City; Juab Co.: Deep Cr. Mtns., Fish Springs, Jericho, Levan, Nephi, Trout Cr.; Kane Co.: Kanab; Millard Co.: Delta, Fillmore, Holden, Oasis, Pahvant, Sci- pio; Rich Co.: Bear Lake Valley, Dry Basin; Sevier Co.: Fremont Jet., Monroe Cyn., Richfield; Tooele Co.: Cedar Mtns., Dugw^ay Proving Grounds, James Ranch, Lakeside Mtns., Little Granite Mtn., Ophir; Uintah Co.: Fort Duchesne, Gusher, 3 mi SW Jensen, Vernal; Utah Co.: Cedar Valley, Lehi, Provo, West Utah Lake; Wasatch Co.: Deer Cr. Reservoir; Washington Co.: Pine Valley, St. George, Zion National Park; Wayne Co.: Notom; Weber Co.: Ogden. 9 June-6 September. Ospriocerus longulus (Loew) 1866: 28 [Holotype: in MCZ]. Utah distribution: Grand Co.: Castleton; Washington Co.: Santa Clara. 8-29 July. Ospriocerus minos Osten Sacken 1877: 291 [Holotype: Male, Golden City, Colorado, 3 July, in MCZ]. Utah distribution: Emery Co.: 3 mi SSE Temple Mtn., San Rafael Desert; Grand Co.: Arches National Monument; Tooele Co. : Dugway Proving Grounds; Uin- tah Go. : 3 mi SW Jensen, Vernal; Utah Co. : 1 mi W Elberta; Wayne Co. : Notom. 25 July-31 July. Ospriocerus vallensis Martin 1968: 401 [Holotype: Male, Grand View, Owyhee Co., Idaho, 9 July 1958, in CAS]. Utah distribu- tion: Box Elder Co.: Cedar Hills, Steamboat Springs, Thiokol; Cache Co.: Providence; Rich Co. : Sage Cr. Jet. ; Sevier Co. : Richfield. 4 June-U July. Saropogon mohawki Wilcox 1966b: 134 [Holotype: Male, Mohawk, Arizona, 16 July 1962, in CAS]. Utah distribution: Washington Co.: Ivins. 16 July. Scleropogon bradleyi (Bromley) 1937a: 309 [Holotype: Male (female on same pin). Grant Forest, California, 9-13 August 1937, in USNM]. Utah distribution: Wayne Co.: 6 mi WTorrey. 15-20 July. Scleropogon coyote (Bromley) 1931: 429 [Syntypes: Male and female, near Lander, Wyoming, July, in OSU]. Utah distribution: Emery Go. : 4 air mi N Gilson Butte; Grand Co.: La Sal Mtns.; Utah Co.: Colton. 20-23 July. Scleropogon duncani (Bromley) 1937a: 307 [Holotype: Male, Silver City, New Mexico, 24 June 1933, in CAS]. Utah distribution: Washington Co.: Rockville, Santa Clara, Zion National Park. 22-24 June. Scleropogon indistinctus (Bromley) 1937a: 308 [Syntypes: Male and female. White Mtns., Arizona, August 1930, in CAS]. Utah distribution: Cache Co.: Logan Cyn., Provi- dence; Daggett Co.: Hideout Cyn., Pipe Cr.; Juab Co.: Nephi; Millard Co.: Antelope Springs; Salt Lake Co.: Salt Lake City; Sevier Co.: Richfield. 26 May-16 August. Scleropogon neglectus (Bromley) 1931: 430 [Syntypes: Male and Female, near Lander, Wyoming, August, in OSU]. Utah distribu- tion: Beaver Co.: Beaver; Box Elder Co.: Clear Cr., Yost; Cache Co.: Beaver Mtn., Hyrum, Logan, Providence; Daggett Co.: Hideout Cyn., Manila; Emery Co.: Buckskin Springs, Goblin Valley; Garfield Go. : Boulder Mtn., 15 mi N Boulder; Grand Co.: La Sal Mtns.; Juab Co.: Callao, Topaz Mtn.; Millard 70 Great Basin Naturalist Vol. 47, No. 1 'AC 93 Laphria fernaldi ,v-.'*- "R ^ Laphria vivax A Laphria janus H Laphria gi1va 95 \7 ^ J>:f^;v^>^::r 1 V / •■ /: u ;■:.;■. - ' ; ,-■■. - • •; 'i', . -.1 ■.x/_. ''[.J^-;'^-'^'" -.~^''"^',~''^-'"■ ■-■', ;' ■- ''^v;;^"" Figs. 93-96. Utah A.silidae, di.stribiiti()n: 93, Laphria fernaldi- 94, Laphria sadalcs and Laphria felis- 95, Laphria vivax, Laphria janus, and Laphria gi/w/; 96, Laphijstia annuhita and Laphystia tohindi. January 1987 Nelson: Utah Robber Flies 71 Co.: Fillmore, Sutherland; Piute Co.: Utah Agricultural Research Station; Rich Co.: Woodruff; Tooele Co.: Camelback, Dugway Proving Grounds, Lakeside Mtns.; Washing- ton Co. : Toquerville. 29 May-16 August. Scleropogon picticornis Loew 1866: 26 [Holotype: Female, California, in MCZ]. Utah distribution: Kane Co. : Kanab; San Juan Co. : Bluff. 20 August-12 September. Sintoria cazieri Wilcox 1972a: 51 [Holo- type: Male, Holden, Utah, 18 September 1959, in AMNH]. Utah distribution: Emery Co.: Goblin Valley; Iron Co.: Beryl; Millard Co.: Holden; Washington Co.: Beaver Dam Slope on Joshua Trees, Red Cliffs Cmpgd. at lights; Weber Co.: Five Points. 16-27 Sep- tember. Stenopogon engelhardti Bromley 1937a: 301 [Syntvpes: Male and female, Jacumba, California,' 26 April 1935, in CAS]. Utah dis- tribution: Box Elder Co.: Raft River Mtns.; Cache Co.: Blacksmith Fork Cyn., Logan Cyn., Tony Grove, Wellsville Cyn.; Daggett Co.: Elk Park; Duchesne Co.:' 30 mi SW Duchesne; Garfield Co.: Boulder Mtn., Bryce Cyn.; Iron Co.: Cedar City; Juab Co.: Eureka; Rich Co.: Logan Cyn. summit; Salt Lake Co.: Dry Cyn., Little Mtn., Salt Lake City; Sanpete Co.: Indianola; Sevier Co.: Richfield; Tooele Co.: Lookout Mtn., Stans- bury Island; Utah Co. : Alpine, Aspen Grove, Payson Cyn., Provo; Washington Co.: Zion National Park; Wayne Co.: Hanksville. 8 June-14 August. Stenopogon inquinatus Loew 1866: 27 [Syntypes: Male and female, Nebraska, in MCZ]. Utah distribution: Beaver Co.: Mil- ford; Box Elder Co.: Cedar Cr., Clear Cr., Cutler Dam, Devils Gate, Mantua, Washakie; Cache Co.: Green Cyn., Logan, Logan Cyn., Providence, Tony Grove, Wellsville Cyn.; Carbon Co.: Dragerton, Price, Woodhill; Daggett Co.: Flaming Gorge, Hideout Cyn., Manila, Spirit Lake Road, Summit Ranger Station; Duchesne Co.: Roosevelt, Yellowstone Ranger Station; Garfield Co.: Boulder Mtn., Bryce Cyn., Es- calante, Panguitch Lake, Tropic; Grand Co.: La Sal Mtns., Westwater; Iron Co.: Parowan Cyn. ; Juab Co. : Fish Springs, Trout Cr. ; Mil- lard Co.: Fillmore, Oak Cr. Cyn.; Piute Co.: Marysvale; Rich Co. : Bear Lake Valley, Lake- town, Logan Cyn. summit. Woodruff; Salt Lake Co.: Big Cottonwood Cyn., Parleys Cyn. , Salt Lake City; San Juan Co. : Bear Ears; Sanpete Co.: Gunnison, Indianola; Sevier Co.: Gooseberry, USDA (center of county); Tooele Co.: Dugway Proving Grounds, Timpie; Uintah Co.: Douglas, Fort Duch- esne, Vernal; Utah Co.: Aspen Grove, Provo Cyn.; Washington Co.: Dixie Park (Snow Cyn.), Zion National Park; Wayne Co.: Boul- der Mtn., Hanksville. 8 May-29 July. Stenopogon martini Bromley 1937a: 303 [Syntvpes: Male and female, Parma, Idaho, 13 May 1934, in CAS]. Utah distribution: Box Elder Co.: Collinston, Fielding, Snowville; Cache Co.: Blacksmith Fork Cyn., Cornish, Logan; Daggett Co.: Manila; Davis Co.: An- telope Island, Bountiful, Farmington; Duch- esne Co.: Bluebell, Roosevelt; Garfield Co.: Panguitch, Panguitch Lake; Grand Co.: Moab; Iron Co. : Miners Peak, Parowan Cyn.; Juab Co.: Eureka, Topaz Mtn.; Millard Co.: Delta, Hatton, McCormick; Rich Co.: Gar- den City, Laketown, Walton (Allen) Cyn.; Salt Lake Co.: Taylorsville; Sanpete Co.: Fountain Green, Indianola, Seely Cr.; Sum- mit Co.: Elk Park Cmpgd.; Tooele Co.: Grantsville, Stansbury Island, Timpie, Ver- non Cyn.; Uintah Co.: Fort Duchesne, Ver- nal; Utah Co. : Aspen Grove, Provo, Spanish Fork; Wasatch Co.: Strawberry Valley; Wayne Co.: Fremont, Torrey; Weber Co.: Ogden, Ogden Cyn., Riverdale. 15 May-6 September. Stenopogon mexicanus Cole 1923: 463 [Holotvpe: Male, Guaymas, Sonora, Mexico, 10 April 1921, in CAS '#1341]. Utah distribu- tion: Cache Co.: Logan; Grand Co.: Castle- ton. 24 July-1 September. Stenopogon rufiharhis Bromley 1931: 431 [Holotype: Male, Lassen Co., California, 20 July 1911, in OSU]. Utah distribution: Beaver Co. : Beaver Cr. ; Box Elder Co. : Devils Gate, Raft River Mtns., Willard Peak; Cache Co.: Blacksmith Fork Cyn., Card Cyn., Logan, Newton, Sardine Cyn., Wellsville; Daggett Co.: Manila; Duchesne Co.: Duchesne; Garfield Co.: Aquarius Plateau, The Pass; Grand Co.: Castle Valley, Moab (La Sal Mtns.); Iron Co.: Cedar City; Juab Co.: Eu- reka, Mt. Nebo; Kane Co. : Alton, Long Val- ley; Rich Co. : Garden City; Salt Lake Co. : Salt Lake City; San Juan Co.: Geyser Pass; San- pete Co.: Fountain Green; Summit Co.: Park City; Tooele Co. : Tooele; Uintah Co. : Vernal; Utah Co.: Alpine, Aspen Grove, Spanish 72 Great Basin Naturalist Vol. 47, No. 1 . Wp] % Laphystia rubra A Laphystia utahensi 97 '"n '"^ .^§ 9 Lasiopogon aldrichii A Lasiopogon albidus ,i.\ \fb) f -^ ^;C., 98 ■■' ^ ^^ ( >r: i\,^::-.: .: ■\. . ,v \ V ' \. '■ . - ■ .^v ■>' . - -- ' ■■./;. 7, 7'-" ^__^_--_^^i_, - % Lasiopogon cinereus M, Lasiopogon monticola 99 JJJJ1\ # Leptogasler spp. 100 .^«:v:. ^"^-^•^ Figs. 97-100. Utah Asilidae, distribution: 97, Laphystia rubra and Laphystia iitahensis \ 98, Lasiopogon aldrichii and Lasiopogon albidus ; 99, Lasiopogon cinereus and Lasiopogon monticola ; 100, Lcptogaster spp. January 1987 Nelson: Utah Robber Flies 73 Fork; Washington Co. : Leeds Cyn. , Pine Val- ley; Wayne Co.: Hanksville; Weber Co.: Og- den. 20 May-25 July. Stenopogon utahensis Bromley 1951: 8 [Syntypes: Male and female, Leeds, Utah, 20 June 1929, in USNM]. Utah distribution: Washington Co.: Leeds, St. George. 1-20 June. Stichopogonfragilis Back 1909: 334 [Holo- type: Female, Alamagordo, New Mexico, 24 April 1902, in AESP]. Utah distribution: Emery Co. : San Rafael Desert 3 mi SSE Tem- ple Mtn. , 5,300 ft; Millard Co. : Delta; Tooele Co. : Dugwav Proving Grounds; Washington Co.: Santa Clara; 3 mi NW St. George. 24 May-4 July. Stichopogon salinus (Melander) 1923c: 216 [Holotype: Male, Great Salt Lake, Utah, 31 July 1908, in Aldrich Collection]. Utah distri- bution: Beaver Co.: Minersville; Cache Co.: Cornish, Logan; Juab Co.: Topaz Mtn.; Mil- lard Co. : Delta, Hatton, Pahvant; Salt Lake Co. : Great Salt Lake; Utah Co. : Aspen Grove, Goshen, Provo, Spanish Fork, west Utah Lake. 20 June-3 August. Stichopogon trifasciatus (Say) 1823: 51 [Holotype: Lost]. Utah distribution: Duch- esne Co. : Indian Creek, Roosevelt; Kane Co. : Kanab, Zion National Park near east entrance; Uintah Co.: Naples; Washington Co.: Santa Clara, Zion National Park. 25 June-19 Au- gust. Tar adieus ruficaudus Cur ran 1930: 4 [Holotype: Female, Mud Springs, Santa Catalina Mtns., Arizona, 17-20 July 1916, in AMNH]. Utah distribution: Alpine. 14 July. Wilcoxia painteri Wilcox 1972b: 43-47 [Holotype: Male, Datil, Continental Divide, Catron Co., New Mexico, 17 July 1930, in Painter Collection?]. Utah distribution: Box Elder Co. : Howell, Nafton, Showell; Emery Co.: east of Block Mtn., Sinbad Country; Garfield Co. : 4 mi N Boulder; Kane Co. : 40 mi E Kanab, 16 mi W Glen Cyn., 3 mi W Wah- weep, Zion National Park near east entrance; Millard Co. : 23 mi W Delta: Uintah Co. : 16 mi SW Vernal; Wayne Co.: east edge Capitol Reef. 19 May-16 September. Willistonina bilineata (Williston) 1883: 11 [Holotype: Female, Northern California, in KU]. Utah distribution: Wasatch Co.: Trout Cr. Spring (near Strawberry Reservoir). 20 August. Subfamily Laphriinae Atomosia mucida Osten Sacken 1887: 184 [Holotype: Sex not known, Presidio, Mexico]. Utah distribution: Washington Co.: Leeds Cyn., Rockville, Santa Clara. 18 July-20 Au- gust. Cerotainiops abdominalis (Brown) 1897: 103 [Holotype: information not found]. Utah distribution: Beaver Co.: Milford; Garfield Co. : Escalante Desert, The Hall; Millard Co. : Hatton, Hinckley, Kanosh; San Juan Co.: Bluff; Tooele Co. : Dugway Proving Grounds. 5 June-12 July. Dasylechia atrox (Williston) 1883: 28 [Holotype: Sex not known, Pennsylvania]. Utah distribution: Cache Co. : Logan. No date on label, Utah specimen in AMNH. Laphria felis (Osten Sacken) 1877: 286 [Holotype: Webber Lake, Sierra Nevada, California, no sex or repository listed in Osten Sacken (1878) or McAtee (1919)]. Utah distri- bution: Box Elder Co.: Willard Peak; Kane Co.: Duck Lake, Navajo Lake; San Juan Co.: Bear Ears; Summit Co.: Trial Lake; Weber Co.: Ogden, Ogden Peak, Willard Peak. 17 June-3 August. Laphria fernaldi (Back) 1904: 290 [Syn- types: Males and females, Colorado, in either UM or AESP]. Utah distribution: Cache Co.: Green Cyn., Logan, Logan Cyn., Twin Creek; Daggett Co. : Elk Park; Duchesne Co. ; Garfield Co.: Bryce Cyn.; Iron Co.: Deer Haven Cmpgd.; Rich Co.: Logan Cyn. sum- mit; San Juan Co.: Bear Ears; Summit Co.: Trial Lake; Uintah Co.: Whiterocks Cyn., Utah Co.: Aspen Grove, Hobble Cr. Cyn., Provo; Washington Co. : Pine Valley, Zion Na- tional Park; Wayne Co.: Hanksville. June-September. Laphria gilva (Linnaeus) 1758: 605 [Holo- type: Lost]. Utah distribution: Cache Co. : Lo- gan; Garfield Co. : Bryce Cyn. 5 June. Laphria janus McAtee 1919: 153 [Holo- type: Male, near summit of Mt. Washington, New Hampshire, in USNM]. Utah distribu- tion: Duchesne Co.: Uinta Mtns.; Garfield Co. : Aquarius Plateau. No dates on labels. Laphria sadales Walker 1849: 378 [Holo- type: Sex not known. New York, in British Museum]. Utah distribution: Cache Co.: Green Cyn.; Duchesne Co.: Mirror Lake, Uinta Mtns.; Rich Co.: Logan Cyn. summit, Monte Cristo; Summit Co.: Hole in Rock 74 Great Basin Naturalist Vol. 47, No. 1 J^Wrl % Machimus adustus 101 •^^ V -•"■•i 9 Machimus griseus 103 '^l^r(-^ r, K, . i- ■■>■ 1 4t^ 0 Machimus callidus n A Machimus sestertius ■^v 'Cp'^---^ 102 A t .,- M ^^{^«: :'--tU Figs. 101-104. Utah Asilidae, distribution: 101, Machimus adti.stus; 102, Machimus callidus and Machimus sestertius, 103, Machimus sriseus , 104, Machimus occidentalis . January 1987 Nelson: Utah Robber Flies 75 Cyn.; Uintah Co.; Utah Co.: A.spen Grove, Provo Cyn. ; Weber Co. : Pineview. 21 July-16 August. Laphria vivax Williston 18(S3: 30 [Holo- type: Sex not known, Washington Territory, no repository hsted in McAtee (1918)]. Utah distribution: Cache Co.: Logan Cyn., Tony Grove; Summit Co.: 3 mi SE Bear River Ranger Station; Wasatch Co.: Silver Lake. 5 August-11 September. Subfamily Asilinae Asilus auriannulatus Hine 1906 [Syntypes: Male and female, Hope Mtns., B.C., 1 July, no repository listed]. Utah distribution: Cache Co.: Blacksmith Fork Cyn., Green Cyn., Little Bear Cr., Logan, Logan Cyn., Twin Creek, Wellsville; Rich Co.: Logan Cyn. summit. 1-26 July. Asilus formosus Hine 1918: 321 [Holotype: Male, Clary Co., Kansas, 29 August 1911, in the Hine Collection (OSU?)]. Utah distribu- tion: Box Elder Co.: 25 mi SW Snowville; Cache Co.: Petersboro; Millard Co.: Fill- more; Tooele Co.: Lakeside Mtns.; Weber Co.: Huntsville. 10 July-13 August. Asilus vescus Hine 1918: 320 [Holotype: Male, Monterrey Co., California, 2 July 1896, in AMNH]. Utah distribution: Box Elder Co. : Willard Basin; Cache Co.: Blacksmith Fork Cyn.; Daggett Co.: Manila; Millard Co.: Delta; Rich Co.: Randolph. 15 June-1 Sep- tember. Efferia aestuans (Linnaeus) 1763: 413 [Holotype: Lost]. Utah distribution: Daggett Co. : Manila; Garfield Co. : Bryce Cyn. ; Wash- ington Co. : Snow Cyn. 19 May-11 August. Efferia albibarbis (Macquart) 1838: 118 [Holotype: Sex not known. North America,' repository not found]. Utah distribution: Cache Co.: Cornish, Logan, Paradise, Wellsville; Duchesne Co.: Myton; Emery Co.: Green River, Woodside; Garfield Co.: Henrieville, Ten Mile (Escalante Desert); Grand Co.: Arches, Castleton, Castle Valley, La Sal Mtns., Moab; Juab Co.: Trout Cr. ; Millard Co.: Delta, Fillmore; San Juan Co.: Bluff; Tooele Co.: Little Granite Mtns.; Uin- tah Co.: Fort Duchesne, Maeser; Utah Co.: east side Utah Lake, Provo; Washington Co.: Leeds, Pinto, Rockville, Santa Clara, Snow Cyn., St. George, Zion National Park — Coal- pits Wash, Narrows; Wayne Co. : Notom; We- ber Co. : Hooper, Riverdale. 7 May-1 August. Efferia apache Wilcox 1966a: 141 [Holo- type: Male, Chambers, Arizona, 18 May 1965, in CAS]. Utah distribution: Emery Co.: 4 mi N Gilson Butte, Goblin Valley, San Rafael Desert, 3 mi SSE Temple Mtn.', 5,300 ft; San Juan Co. : Bluff. 16 April-29 May. Efferia arida (Williston) 1893: 254 [Holo- type: Male, Death Valley Expedition, April 1891, in USNM]. Utah distribution: Washing- ton Co.: Leeds. 4-23 April. E/jTerifl [;asmi Wilcox 1966a: 190 [Holotype: Male, 28.5 mi W Eureka, Eureka Co., Ne- vada, 6 Jime 1960, in CIS]. Utah distribution: Box Elder Co.: Cedar Cr., Snowville; Grand Co.: 12 mi NW Moab; Wayne Co.: Horse Valley. 28 May-19 June. Efferia benedicti (Bromley) 1940: 15 [Holo- type: Male, Winslow, Arizona, 13 June 1937, in KU]. Utah distribution: Beaver Co.: Mil- ford, Minersville Reservoir; Box Elder Co.: Clear Cr., Kelton, Lampo Jet., Mantua, Promontory, Raft River Mtns., Rattlesnake Pass, Snowville, Tecoma Range; Cache Co.: Beaver Mtn., Blacksmith Fork Cyn., Dry Cyn., Green Cyn., Logan, Logan Cyn., Prov- idence; Carbon Co. : Carbon Airport, Drager- ton, Kennilworth, Price, Woodhill; Davis Co.: Antelope Island, Farmington; Daggett Co.: Bridgeport; Duchesne Co.: Duchesne; Emery Co.: Buckskin Springs, Block Mtn., 4 mi N Gilson Butte, Sinbad Country; Garfield Co.: Boulder, 11 mi E Escalante, Escalante Desert, Halls Cr. , Long Hollow, Shitamaring Cyn., Ten Mile, Willow Tanks; Grand Co.: Castle Valley, Moab; Iron Co. : Cedar City, Parowan; Juab Co.: Antelope Springs, Callao, Deep Cr. Mtns., Levan, Thomas Range, To- paz Mtn., Trout Cr., Utah Agricultural Ex- periment Station north of Levan; Kane Co. : Glendale, Kanab, Kodachrome Basin, Zion National Park; Millard Co.: Confusion Pass, Delta, Fillmore, Flowell, Garrison, Hatton, Oak City, Pahvant, Scipio Lake; Piute Co.: Marysvale; Salt Lake Co.: Dry Cyn., Fort Douglas, Salt Lake City; San Juan Co. : Bland- ing, Hite, Kane Springs, Lime Cr., Monti- cello, Bluff, Monument Valley, Natural Bridges National Monument, Navajo Mtn. Trading Post; Sanpete Co.: 8 mi NE Fountain Green; Sevier Co.: Fish Lake, Fremont Jet., Gooseberry, Richfield; Tooele Co.: Cedar Mtns., Clifton, Delle, Dugway Mtns., be- tween Johnson and Douglas passes. Lookout Mountain, Skull Valley, Simpson Springs, 76 Great Basin Naturalist Vol. 47, No. 1 0 Machimus paropus 105 i,/';:\-v: ■■, V-. . W&i ■ j(^M- ^K '":"> "^''- 1 ■'■')■' .■.>. ;> -■>-•/-- ».'-.- 0 Meqaphorus frustra ^ Megaphorus pulcher 107 VJSL. j;^ 9 Megaphorus will istoni A Megaphorus guildiana Figs. 105-108. Utah Asilidae, distribution: 105, Machimus paropus , 106, Mallopliura fantrix and Megapliorus pallidus; 107, Megaphorus frustra and Megaphorus pulcher, 108. Megaphorus willistoni and Megaphorus guildiana . January 1987 Nelson: Utah Robber Flies 77 Stansbury Island, Tinipie, Wendover; Uintah Co.: Dinosaur National Monument, Evacua- tion Cr., Vernal; Utah Co.: Alpine, Aspen Grove, Cedar Valley, Goshen, Oquirrh Mtns., Payson, Provo, Rock Cyn., Spanish Fork, West Cyn., west Utah Lake, Y Mtn.; Washington Co.: Beaver Dam Mtns., Dixie National Forest, Hurricane, Ivins, Leeds Cyn., St. George, Summit, Toquerville, Veyo, Zion National Park; Wayne Co. : Exper- iment Station, Fruita, Grover, Hanksville, Notom, Torrey, 6 mi W Torrey; Weber Co.: FarrWest, North Ogden, Ogden. 23April-28 August. Efferia bicolor (Bellardi) 186L 47 [Holo- type: Male, 'Mexico,' repository not hsted in Wilcox (1966)]. Utah distribution: Box Elder Co.: Kelton; Cache Co.: Logan; Daggett Co.: Bridgeport, Hideout Cyn.; Iron Co.: Cedar City; Juab Co.: Trout Cr.; Washington Co.: Zion National Park. 19 July-24 July. Efferia cana (Hine) 1916: 22 [Syntypes: Males and females, Claremont, California, in OSU]. Utah distribution: Juab Co.: Fish Springs; Kane Co.: Wahweep Va.; Millard Co. : Delta; Utah Co. : Provo; Washington Co. : 15 mi SW Shivwits, Hurricane, La Verkin, Leeds, Pintura, Santa Clara, St. George, 3 mi N St. George; Wayne Co.: Hanksville. 23 April-1 June. Efferia costalis (Williston) 1885: 64 [Holo- type: None hsted]. Utah distribution: Box El- der Co.: Curlew Valley; Cache Co.: Franklin Basin; Carbon Co.: Price; Daggett Co.: Elk Park; Duchesne Co. : Yellowstone Ranger Sta- tion; Garfield Co.: Bryce Cyn., Daves Hol- low, Panguitch Lake; Iron Co.: Kanarraville; Kane Co.: Coral Pink Sand Dunes; Millard Co.: Antelope Mtn.; Rich Co.: Sage Cr. Jet.; Sah Lake Co.: Parleys Cyn.; San Juan Co.: Blanding; Tooele Co.: James Ranch — Gov- ernment Spring; Washington Co. : New Har- mony. 9 June-7 August. Efferia davisi Wilcox 1966a: 132 [Holotype: Male, 12 mi N Sasabe, Arizona, 5 August 1962, in CAS]. Utah distribution: Washington Co.: Ivins, Leeds, Rockville, Santa Clara, Zion National Park. 15-19 July. Efferia deserti Wilcox 1966a: 199 [Holo- type: Male, 10 mi E Desert Center, Califor- nia, 13 April 1941, in CAS]. Utah distribution: Washington Co.: Santa Clara, St. George, Zion National Park. 4-15 May. Efferia frewingi Wilcox 1966a: 169 [Holo- tvpe: Male, Antelope Mtn., Harney Co., Ore- gon, 6,500 ft, 9 August 1931, in CAS]. Utah distribution: Box Elder Co. : Clear Cr. , Kelton Pass, Promontory, Yost; Cache Co.: Logan; Daggett Co.: Dutch John, Hideout Cyn., Manila; Duchesne Co.: Duchesne, Monarch, My ton, Roosevelt, 10 mi N Neola; Emery Co.: Buckhorn Flats, fossil beds. Green River, Gilson Butte; Garfield Co.: Hen- rieville, Henry Mtns.; Juab Co.: Eureka, To- paz; Kane Co.: Zion National Park — Cham- berlain Ranch; Millard Co.: Fillmore, Desert Experiment Station; Sanpete Co.: 8 mi NE Fountain Green; Sevier Co.: Richfield; Tooele Co.: Clifton, Little Granite Mountain; Uintah Co.: Diamond Mtn., Dinosaur Na- tional Monument, Jensen, Red Wash, Vernal; Utah Co.: Alpine, Goshen, Provo, west Utah Lake; Wasatch Co. : Strawberry Valley; Wash- ington Co.: Crystal Cr., Hurricane, Leeds, Pintura. 26 July-8 September. Efferia knowltoni (Bromley) 1937b: 104 [Syntypes: Male and female. Trout Creek, Utah, 5-6 1934, in USU or USNM ( not seen at USU)]. Remarks: A specimen labeled Trout Creek, Utah, 5-6 1934 but without a type label in the USU collection was examined, and it ran to Efferia benedicti in the Wilcox (1966a) key. No male specimens examined during this study, including numerous speci- mens from Trout Creek, ran to this species in the key. Some females do indeed run to this species based on the position of the fork of the third vein (in the Wilcox key). Upon closer observation this character was found variable in the specimens, even in those from the same locality. Therefore, status of this species should be that of synonomy under £ . bene- dicti until characters separating this species can be found. Efferia mortensoni Wilcox 1966a: 173 [Holotype: Male, 2 mi NE Portal, Arizona, 23 October 1962, in CAS]. Utah distribution: Snow Cyn., St. George. 7 October. Efferia pernicus Coquillett 1893: 175 [Syn- types: Male and female, Los Angeles and San Diego counties, California, in USNM]. Utah distribution: Kane Co.: Zion National Park — Chamberlain Ranch; Washington Co. : Boilers in Washington, Rockville — Duncan Flats. 29 July-5 September. Efferia producta (Hine) 1919: 136 [Syn- tvpes: Male and female, Flinn Springs, Lakeside, California, 9 August 1917, in OSU]. 78 Great Basin Naturalist Vol. 47, No. 1 Wetapoqon carinatus Myelaphus lobicornis hlannocyrtopoqon aristatus W W- 9 niw Negasilus mesae 111 ■5"^-^;*'-^ii:*-2i:;L...::.„.: \\^¥ M^ •:^:l ; ^'' ■f^W%*i':f;r'""'Xrj^-: Af^.y.j} % Neoitamus brevicomus ^ Ntomochtherus albicomus w Weomochtherus hypopygialis I Weomochtherus lepidus 112 '*v*v^lL Figs. 109-112. Utah Asilidae, di.strihution: 109, Mctapo^on carinatus, Myelaphus lobicornis, and Nannocyrto- pogon aristatus ; 110, Negasilus belli , 111, Negasilus mcsae; 112, Neoitamus brevicomus , Neomochtherus albicomus , Neomochtherus hypopygialis , and Neomochtherus lepidus. January 1987 Nelson: Utah Robber Flies 79 Utah distribution: Kane Co. : Kanab; San Juan Co.: Navajo Mtn.; Washington Co.: Zion Na- tional Park. 17 July-28 August. Efferia staminea (Williston) 1885: 68 [Holo- type: Male, Montana, in KU]. Utah distribu- tion: Daggett Co. : Pipe Creek. 6 August. Efferia subarida (Bromley) 1940: 14 [Holo- type: Types — male and female, Tucson, Ari- zona, 8 March 1937, in KU]. Utah distribu- tion: Garfield Co.: Shitamaring Cyn. 18 May. Efferia siibcuprea (Schaeffer) 1916: 66 [Holotype: Male, Prescott, Arizona, in USNM]. Utah distribution: Beaver Co.: Beaver: Box Elder Co.: Willard Basin; Garfield Co.: Aquarius Plateau; Grand Co.: Moab; Iron Co.: Parowan; Kane Co.: Paria River; San Juan Co.: Kane Springs; Tooele Co.: Little Granite Mtn.; Utah Co.: Provo Cyn. ; Washington Co. : Zion National Park. 29 June-29 August. Efferia siibpilosa (Schaeffer) 1916: 67 [Holotype: Male, Beaver Creek Hills, Beaver Co., Utah, in USNM]. Remarks: Wilcox (1966a) sensed problems with respect to the identity of this species. Apparently no speci- mens which he studied could confidently be placed in this species. I have not seen any specimens which would fit the descriptions outlined by the Wilcox (1966a) key. The type should be examined to determine the status of this species. Efferia tucsoni Wilcox 1966a: 231 [Holo- type: Male, Portal, Arizona, 23 July 1963, in CAS]. Utah distribution: Garfield Co.: Shita- maring Cyn.; San Juan Co.: Natural Bridges National Monument; Washington Co.: Leeds Cyn., Paradise Cyn. (nearlvins), Santa Clara, Zion National Park. 14-27 July. Efferia utahensis (Bromley) 1937b: 103 [Holotype: Male, Price, Utah, 26 August 1935, in USU or USNM (not seen at USU)]. Utah distribution: Carbon Co.: 1 mi S Price; Emery Co.: 2 air mi W Little Gilson Butte, Goblin Valley (in wash), 4 air mi N Gilson Butte; Garfield Co.: Henry Mtns., Wickiup Pass; Grand Co.: Westwater; San Juan Co.: 8 mi NE Mexican Hat. 15 August-17 Septem- ber. Efferia willistoni (Hine) 1919: 110 [Syn- types: Male and female, Williams, Arizona, 21 July, in USNM]. Utah distribution: Cache Co.: Green Cyn., Logan Cyn.; Grand Co.: Castleton, La Sal Mtns.; Millard Co.: Cove Fort, Fillmore; Salt Lake Co.: Magna, Salt Lake City; San Juan Co. : Grand Gulch, Natu- ral Bridges National Monument; Washington Co. : Crystal Cr. , Deep Cr. , Leeds Cyn. , Zion National Park — Court of the Patriarchs, Oak Cr. 6 May-6 August. Efferia zonata (Hine) 1919: 112 [Syntypes: Male and female, southern Arizona, August 1902, in OSU]. Utah distribution: Box Elder Co. : Clear Cr. , 5 mi N Kelton, Mantua; Cache Co.: Blacksmith Fork Cyn., Dry Cyn., Green Cyn., Hatties Grove, Logan, Providence Cyn.; Daggett Co.: 14 mi S Manila; Emery Co.: San Rafael Reef, S. Temple Wash; Garfield Co. : Henrieville; Juab Co. : Antelope Springs; Millard Co.: Delta, Fillmore, Gaudy; San Juan Co.: Hite; Sanpete Co.: Ephraim; Tooele Co.: Deep Cr. Mtns., Hick- man Cyn., Johnson Pass, Mercur, Whiskey Springs; Utah Co.: Payson, Provo; Washing- ton Co.: Leeds, Snow Cyn., Zion National Park. 30 June-28 August. Machimus adustus Martin 1975: 27 [Holo- type: Male, White Mtns., Bee Hive Springs, Arizona, 18 July 1949, in CAS]. Utah distribu- tion: Beaver Co.: Milford; Box Elder Co.: Clear Cr., Mantua; Cache Co.: Green Cyn., Logan, Logan Cyn., Tony Grove, Twin Cr., West Hodges Cyn.; Daggett Co.: 4 mi E Deep Cr., Pipe Creek Summit Ranger Sta- tion; Garfield Co.: Boulder, Bryce Cyn.; Mil- lard Co. : Delta; Rich Co. : Garden City, Logan Cyn. summit; San Juan Co.: Kane Springs, Navajo Mtn.; Sanpete Co.: Centerfield; Sum- mit Co. : 16 mi "P Kamas; Tooele Co. : Tooele; Uintah Co.: Whiterocks Cyn.; Utah Co.: As- pen Grove; Wasatch Co.: Keetley, Straw- berry Reservoir; Washington Co.: Kolob, Pine Valley, Zion National Park — East Rim, Lava Point; Weber Co.: Huntsville, Uintah. 20 June-18 September. Machimus callidus Williston 1893: 75 [Syn- types: Male and female, Mt. Hood, in KU]. Utah distribution: Box Elder Co.: Clear Cr., Willard Basin, Yost; Cache Co.: Blacksmith Fork Cyn., Franklin Basin, Green Cyn., Lo- gan, Logan Cyn., Providence, Tony Grove, White Pine Lake; Daggett Co.: Hideout Cyn., Manila; Grand Co.: Castle Valley; Juab Co.: Trout Cr.; Rich Co.: Logan Cyn. sum- mit, Monte Cristo, Walton (Allen) Cyn.; Tooele Co.: Vernon; Uintah Co.: Jensen; Washington Co.: Zion National Park. 6 May-10 September. Machimus griseus Hine 1906: 29 [Syntypes: 80 Great Basin Naturalist Vol. 47, No. 1 A Nicodes abdominal is # Nicocles utahensis * S^^'-v- K' -trr-'S' W)^^^U-m^ Ospriocerus abdominal is Ospriocerus vallensis ^TWI % Ospriocerus longulus A Ospriocerus minos H Saropogon mohawki ^Philonicus arizonensis ¥ Sintoria cazieri 115 ' ':'/ ■-''.J >i-',J '■--- :U:;-i!fl§#i^:- A ▲ ^;^% .'"^:'. '1^:if:-«^V- jV,^-:, '--- ----- ■■A -. Figs. 113-116. Utah Asilidae, distribution: 113, Nicocles ahdominalis and Nicocles utahensis; 114, Ospriocerus abdominalis and Ospriocerus vallensis; 115, Ospriocerus longulus. Ospriocerus minos, Saropogon mohawki, and Sintoria cazieri ; 116, Philonicus arizonensis and Philonicus limpidipcnnis . January 1987 Nelson: Utah Robber Flies 81 Male and female, 'Southwestern Colorado," no repository listed]. Utah distribution: Cache Co.: Blacksmith Fork Cyn.; Daggett Co.: Manila; Grand Co.: Castleton; Juab Co.: Callao; Kane Co. : Kanab; San Juan Co. : Natu- ral Bridges National Monument; Uintah Co.: Fort Duchesne, Whiterocks; Utah Co.: Hob- ble Cr. Cyn.; Washington Co.: Boilers — Washington, Crystal Cr., Deep Cr., Leeds, Zion National Park — Court of the Patriarchs; Wayne Co. : Grover. 10 July-12 September. Machimus occidentalis (Hine) 1909: 147 [Type: None designated, several specimens, noted by Hine (1909) from B.C., Nevada, California, Oregon, and Washington]. Utah distribution: Box Elder Co.: Clear Cr., Curlew Valley, Hansel Valley, Mantua, Raft River Mtns.; Cache Co.: Ant Valley, Black- smith Fork Cyn., Green Cyn., Logan Cyn., Providence, Tony Grove, Twin Creek; Grand Co.: La Sal Mtns.; Juab Co.: Trout Cr.; Mil- lard Co.: Delta, Holden; Rich Co.: Logan Cyn. summit; San Juan Co.: 25 mi S Moab; Uintah Co. : Jensen; Utah Co. : South Fork of Provo Cyn.; Washington Co.: Leeds, Pine Valley, Zion National Park; Weber Co. : Og- den. 3 June-25 July. Machimus paropus (Walker) 1849: 455 [Holotype: Not listed in Hine (1909)]. Utah distribution: Beaver Co.: Milford; Box Elder Co.: Grouse Cr., 25 mi SW Snowville; Cache Co.: Clarkston, Cornish, Mendon, Peters- boro, Richmond, Smithfield Cyn.; Carbon Co.: Helper; Daggett Co.: Manila; Juab Co.: Chicken Cr. Reservoir; Millard Co.: Delta, Fillmore; Rich Co. : Laketown, Randolph; Salt Lake Co. : Midvale; Sanpete Co. : Centerfield, Ephraim, Fayette, Sanpete; Tooele Co.: Mills Jet.; Uintah Co.: Fort Duchesne; Utah Co.: American Fork, Provo, South Fork of Provo Cyn., Spanish Fork; Washington Co.: St. George; Weber Co.: Huntsville. 6 May-2 September. Machimus sestertius Martin 1975: 29 [Holotype: Male, 4.5 mi E Moenkopi, Co- conino Co., Arizona, 14 July 1966, in CAS]. Utah distribution: Kane Co.: Coral Pink Sand Dunes, Kanab, 10 mi N Kanab; Tooele Co. : Dugway Proving Grounds; Washington Co.: Crystal Cr., Deep Cr., Santa Clara, St. George, Zion National Park. 13 May-21 Sep- tember. MallophorafautrixOsten Sacken 1877: 191 [Holotype: Presidio, Mexico, no sex or reposi- tory listed]. Utah distribution: Uintah Co.: Randlett (?); Washington Co.: La Verkin, St. George, Washington, Zion National Park. 4 July-15 August. Megaphorus frustra (Pritchard) 1935: 11 [Holotvpe: Male, Tem (south of Whitewater), Arizona, 19 August 1934, in AMNH]. Utah distribution: Garfield Co.: Cass Cr. Reser- voir; Iron Co.: Cedar City, Iron Springs, Parowan; Kane Co.: Kanab; Millard Co.: Chalk Cr. , Leamington; San Juan Co. : Bland- ing, Monticello; Tooele Co.: Cedar Mtns.; Washington Co.: Anderson Jet., Ash Cr., Gunlock, Leeds Cyn., Little Pinto, Pintura, Utah State Line U 59, Zion National Park. 14 June-26 August. Megaphorus guildiana (Williston) 1885: 60 [Types: western Kansas, Montana, North Carolina, in KU]. Utah distribution: Box El- der Co.: Snowville; Cache Co.: Green Cyn., Logan; Daggett Co.: Forest Camp, Hideout Cyn.; Juab Co.: Nephi; Kane Co.: Kanab; Sanpete Co. : Fairview; Uintah Co. : La Point, Tridell. 5-23 August. Megaphorus paUidus (Johnson) 1958: 41 [Holotype: Male, west side of Little Granite Mtn., Tooele Co., Utah, 21 August 1955; in Johnson collection (paratypes seen at BYU)]. Utah distribution: Millard Co.: 9 mi E Delta; Tooele Co.: Cedar Mtns., Hickman Cyn., Simpson Mtns., west side of Little Granite Mtn. 23 July-21 August. Megaphorus pulcher (Pritchard) 1935: 11 [Holotype: Carlsbad, New Mexico, 29 August 1934, in AMNH]. Utah distribution: Wash- ington Co.: Enterprise, Middleton, Pine Val- ley, Rockville, St. George, Zion National Park. 10 August-14 October. Megaphorus willistoni (Cole,) in Cole and Pritchard 1964: 74 [Holotype: Male, Hallelu- jah Jet., Lassen Co., California, 26 July, in CAS]. Utah distribution: Beaver Co.: Beaver; Box Elder Co.: Clear Cr.; Cache Co.: Black- smith Fork Cyn., Green Cyn., Logan; Emery Co. : Block Mtn. , Sinbad Country; Grand Co. : Moab; Millard Co.: Fillmore; Salt Lake Co.: Salt Lake City; Sanpete Co. : 8 mi NE Foun- tain Green; Utah Co.: BYU, Provo, Rock Cyn., Spanish Fork, Spring Lake; Washing- ton Co.: Zion National Park. 8-24 August. Negasilus belli Curran 1934: 184 [Holo- type: None listed]. Utah distribution: Box El- der Co.: Portage; Cache Co.: Logan, Men- don; Duchesne Co.: Duchesne; Garfield Co.: 82 Great Basin Naturalist Vol. 47, No. 1 \A .im ■'■■ '^■ # Proctacanthus micans A Proctacanthus milbertii i . 117 V ,<■ •^1? ; Mr • Proctacanthus nearno y i^"- A Proctacanthus hinel \ ^ ■^ ''. ■'V'^v \ ^a ^ — ) ^j _-_-" v^>~ '"r* ..^'i -~L--<: "V~V <-•')' 118 . '' lA > ^ i^5 K- ' \ -: ■ < '. j- .-, '- ' ■• X! ^''-C ■' ''-■-.. -v' iT* ' /: '.^ ; -. i ^■' O''^'",,-^----- -i-^--- -,-:-"- ^i. --/■ • ; \^^!'f'.'* •:'';''- ' • .^-.-^T^' 1'':. '"_' "' ., ' ,':i . ' '; i;'- ' >* :a.; Pol acantha compos i ta AProctacanthel la cacopilopa <^'ifX- m^^ V •• 'mr\ 9 Promachus albifacies 120 Mrm Figs. 117-120. Utah Asilidae, distribution: 117, Proctacanthus micans and Proctacanthus milbertii- 118, Procta- canthus nearno and Proctacanthus hinei; 119, Polacantha composita and ProctacantheUa cacopiloga ; 120, Promachus albifacies . January 1987 Nelson: Utah Robber Flies 83 Boulder; Juab Co.: Chicken Cr., Nephi; Mil- lard Co.: Delta; Rich Co.: Laketown, Ran- dolph, Walton (Allen) Cyn., Woodruff; San- pete Co.: Fairview; Sevier Co.: Koosharem Reservoir; Uintah Co.: Vernal; Utah Co.: Provo; Washington Co.: Santa Clara, Virgin, Zion National Park. 13 June-23 July. Negasilus mesae (Tucker) 1907: 51 [Holo- type: Colorado Springs, Colorado, in KU]. Utah distribution: Box Elder Co.: Bird Refuge, Blue Cr., Brigham City, Corinne, Howell, Kelton, Locomotive Springs, Nafton, Snowville; Cache Co.: Beaver Mtn., Benson, Cornish, Logan Cyn. — Twin Cr.; Daggett Co.: Manila; Duchesne Co.: Myton; Emery Co.: 9 air mi E Castledale, Sinbad Country east of Block Mtn.; Crand Co.: Moab; Kane Co.: Navajo Lake; Millard Co.: Delta, Pah- vant; Rich Co.: Sage Cr. Jet., Woodruff; San Juan Co.: Kane Springs; Sanpete Co.: Indi- anola; Sevier Co. : Fish Lake, Sevier; Summit Co.: Park City; Tooele Co.: Delle, losepa, Timpie; Uintah Co.: Jensen; Utah Co.: El- berta, Fairfield; Wasatch Co.: Heber, Provo Cyn. 18 May-12 August. Neoitamus brevicomus (Hine) 1909: 155 [Syntypes: Male and female, Kalso, B.C., repository not listed]. Utah distribution: Garfield Co. : Long Hollow; Rich Co. : Monte Cristo; Salt Lake Co. : Mill Creek Ranger Sta- tion; Utah Co.: Aspen Grove. 12 July-11 Au- gust. Neomochtherus albicomus {Hine) 1909: 136 [Syntvpes: Male and female, Montana, in USNM]. Utah distribution: Box Elder Co.: Clear Cr. ; Cache Co. : Green Cyn. , Twin Cr. ; Daggett Co.: Hideout Cyn., Manila. 19 July— 4 September. Neomochtherus hypopygialis (Schaeffer) 1916: 68 [Syntypes: Two males, Beaver Cyn., Utah, in AMNH]. Remarks: No specimens of this species were seen in collections during this study. Neomochtherus lepidus (Hine) 1909: 136 [Holotype: Male, Colorado, also female. White Mtns. of New Mexico about 6,000 ft, 23 July, in USNM]. Utah distribution: Box Elder Co.: Clear Cr.; Uintah Co.: Bonanza; Wash- ington Co.: Pine Valley, Zion National Park. 24 August. Philonicus arizonensis (Williston) 1893: 76 [Holotype: Female, Arizona, in KU]. Utah distribution: Kane Co.: Long \'alley; Millard Co.: Fillmore, Kanosh Cyn.; Washington Co.: Crystal Cr., Deep Cr. , Leeds Cyn., Rockville, Zion National Park — Birch Cr., Coalpits Wash, Court of the Patriarch, Nar- rows, Taylor Cr. 17 June-28 August. Philonicus limpidipennis (Hine) 1909: 167 [Syntypes: Male and female, southwestern Colorado, 14 July 1899, repository not listed]. Utah distribution: Grand Co.: Moab; Juab Co. : Callao; Salt Lake Co. : Salt Lake City; San Juan Co.: Indian Cr.; Sevier Co.: Richfield; Uintah Co. : Vernal Refuge; Utah Co. : Spanish Fork; Washington Co. : Rockville. 18 June-30 August. Polacontha composita (Hine) 1918: 321 [Holotype: Male, San Diego, California, 30 June 1913, in Hine Collection]. Utah distribu- tion: Cache Co. : Logan; Iron Co. : Cedar City; Juab Co.: Trout Cr.; Utah Co.: Saratoga; Washington Co.: Leeds, Leeds Cyn., Par- adise Cyn., St. George, Virgin, Zion National Park. 27 June-28 August. Proctacanthella cacopiloga (Hine) 1909: 65 [Syntypes: Several specimens from many states, see Hine (1909), in KU]. Utah distribu- tion: Daggett Co.: Manila; Duchesne Co.: Roosevelt; Emery Co.: Green River, Wild Horse Cr. north of Goblin Valley; Grand Co.: 12 mi NW Moab; Uintah Co.: Vernal. 6 June-16 August. Proctacanthus hinei Bromley 1928: 13 [Holotype: male, Albuquerque, New Mexico, 3 August 1925, S. W. Bromley., in Bromley Collection]. Utah distribution: San Juan Co.: Sand Island Cmpgd. 2 mi S Bluff. 22-23 Au- gust. Proctacanthus micans Schiner 1867: 397 [Holotype: None listed in Hine (1911)]. Utah distribution: Duchesne Co.: Boneta; Kane Co.: Kanab, Zion National Park; Millard Co.: Delta; San Juan Co.: Navajo Mtn.; Uintah Co.: Bonanza, Fort Duchesne, Jensen, Ver- nal; Washington Co. : Leeds Cyn. , Pine Valley Cmpg, Zion National Park; Wayne Co.; We- ber Co.: Farr West, Ogden. 15 July-19 Au- gust. Proctacanthus milberti Macquart 1838: 124 [Holotype: None listed in Hine (1911)]. Utah distribution: Cache Co.: Cornish; Daggett Co.: Manila; Duchesne Co.: Roo- sevelt; Uintah Co. : Vernal; Utah Co. : Goshen; Washington Co.: Zion National Park. 27 June-11 August. Proctacanthus nearno Martin 1962: 187 [Holotype: Male, Baboquivari Mtns., Ari- 84 Great Basin Naturalist Vol. 47, No. 1 y" TW\ Promachus dimidiatus ▲ P romachus sackeni 122 y,i' 'T^i;- ';■ '■■'"a^^^'aI''^:- Vi # Triorla interrupta A Rugasilus blantoni 123 ^^^f^^lf^^j^ •h *|.'~0 ♦ Scleropogon indistinctus Ascleropogon coyote B S<:^^''opo90" duncani 124 ' >- '< ■'•..'■ ■'.%-''■< " ' .■■■ :'■ ; ;■'['■ --i.rxy^ '---V-:'^ :_:-_i-Ai-^~- ■ -s---.' - -.'■■ Figs. 121-124. Utah Asilidae, distribution: 121, Promachus aldrichii, 122, Promachus dimidiatus and Promachus sackeni, 123, Triorla interrupta and Re^asihis blantoni, 124, Scleropof^on indistinctus , Scleropogon coyote, and Scleropogon duncani . January 1987 Nelson: Utah Robber Flies 85 zona, 19 July 1950, in KU], Utah distribution: Cache Co.: Cornish; Carbon Co.: Price; Daggett Co.: Bridgeport; Duchesne Co.: Bluebell, Uintah Cyn.; Emery Co.: Wild- horse Cr. north of Goblin Valley, 4 mi N Gilson Butte, 2 mi E Little Gilson Butte; Garfield Co.: Boulder, Ten Mile, The Halls; Grand Co.: Castleton, Moab; Juab Co.: Callao; Kane Co.: Coral Pink Sand Dunes; Millard Co.: Delta, Fillmore; San Juan Co.: Goulding; Sevier Co.: Richfield; Tooele Co.: Skull Valley; Utah Co. : Provo, Spanish Fork; Washington Co.: Duncan Flats near Rockville, Leeds Cyn., Middleton, Rockville, Santa Clara, Shunesburg, Zion National Park — Coalpits Wash; Wayne Co.: Hanks- ville; Weber Co. : Ogden Cyn. 19 July-5 Sep- tember. Promachus albifacies Williston 1885: 63 [Holotype: Sex not known, Arizona, in KU]. Utah distribution: Box Elder.: Clear Cr. Cyn.; Cache Co.: Logan; Daggett Co.: Pipe Cr., Manila; Davis Co.: Wasatch Forest boundary near Bountiful; Garfield Co.: Aquarius Plateau, Escalante, Panguitch; Mil- lard Co.: Kanosh Cyn.; Piute Co.: Junction; Tooele Co. : Lake Point; Uintah Co. : La Point; Utah Co.: American Fork, Lehi, Provo; Washington Co. : Ash Cr. bridge, Leeds Cyn. , Pinto, Zion National Park; Wayne Co.: Hanksville. 10 June-11 August. Promachus aldrichii Hine 1911: 171 [Syn- types: Male and female, Utah, repository not listed, probably in Hine Collection or OSU]. Utah distribution: Beaver Co.: Beaver, Mil- ford, Minersville Reservoir; Box Elder Co.: Collinston; Cache Co.: Logan, Petersboro; Daggett Co.: Bridgeport, Manila; Duchesne Co.: 10 mi N Neola; Emery Co.: Paige Flat, Sinbad Country; Grand Co.: Castle Valley, Moab; Iron Co.: Cedar City; Juab Co.: Eu- reka, Nephi, Topaz Mtn., Trout Cr.; Kane Co.: Escalante Desert, Willow Tank; Millard Co.: Confusion Pass, Desert Research Sta- tion, Pahvant; Salt Lake Co.: Hunter; San Juan Co. : Piute Pass near Grand Gulch; San- pete Co. : 8 mi NE Fountain Green, Fairview; Tooele Co.: Cedar Mtns., Delle, Dugway Proving Grounds, Flux, Hickman Cyn., In- dian Springs, Mercur, Skull Valley, Whiskey Springs; Uintah Co.: Bonanza, Dinosaur Na- tional Monument, Jensen, Vernal, White- rocks; Utah Co.: Lehi, Orem, Rock Cyn., west Utah Lake; Washington Co.: Beaver Dam Mtns., Leeds, old airport. Paradise Cyn., Rockville, St. George, Washington, Zion National Park; Wayne Co.: Teasdale. 8 June-17 September. Promachus dimidiatus Curran 1927: 87 [Holotype: Male, Aweme, Manitoba, July 1920, in CNC]. Utah distribution: Cache Co.: Logan. 4-20 July. Promachus sackeni Hine 1911: 166 [Syn- types: Male and female, southern Arizona, July and August, no repository listed]. Utah distribution: Washington Co.: Leeds Cyn., Zion National Park. 4-20 July. Regasilus blantoni Bromley 1951: 35 [Holo- type: Male, Wills (Wells?), Nevada, 19 Au- gust 1939, in Bromley Collection]. Utah dis- tribution: Millard Co.: Skull Rock Pass; Washington Co. : Beaver Dam slope near Ari- zona border. 10 September-8 October. Triorhi interrupta (Macquart) 1834: 310 [Holotype: Georgia, location unknown]. Utah distribution: Cache Co.: Cornish, Logan; Garfield Co. : Bryce Cyn. ; Uintah Co. : White- rocks; Washington Co.: Rockville — Duncan Flats, confluence East and North forks Virgin River, St. George. 10 July-11 August. Acknowledgments Thanks are given to W. J. Hanson, G. F. Knowlton, and G. E. Bohart of Utah State University for help given during the prepara- tion of the thesis from which this publication is derived. Additional thanks are given to the following curators and institutions which al- lowed use of their specimens: S. L. Wood and R. W. Baumann, BYU; M. Fors, UU; A. Bar- num, Dixie College; R. D. Anderson, SUSC; andL. King, CEU. I thank J. K. Nelson and J. A. Stanger for help with the illustrations, the J. Wilcox family for permission to use the drawings of Efferia terminalia, and A. Provonsha for the map. Many thanks are ex- tended to the D Elden Beck family for provid- ing funds to publish this work. List OF Museum Abbreviations AESP American Entomological Society, Philadelphia AMNH American Museum of Natural History BYU Brigham Young University CAS California Academy of Sciences CEU College of Eastern Utah CIS California Insect Survey CNC Canadian National Collection 86 Great Basin Naturalist Vol. 47, No. 1 # Stenopogon engelhardti ' .-^ ^* i^ I . • '^ -' •• :ii|.:f i^:.^_ Figs. 12.5-128. Utah Asilidae, distribution: 12.5, Scleropo^on nefilectiis, Sclcropo^on picticonm , and Scleropogon bradleyi, 126, Stenopogon engelhardti- 127. Stenopogon inqiiinatus ■ 128, Stenopogon martini. January 1987 Nelson: Utah Robber Flies 87 CSU Colorado State University KU UniversitN' of Kansas MCZ Museum of Comparative Zoology OSU Ohio State University SUSC Southern Utah State College UM L^niversity of Massachusetts USNM United States National Museum USU Utah State University UU University of Utah Literature Cited Adisoemarto. S . AND D M Wood 1975. The Nearctic species oWioctria and six related genera (Diptera: Asihdae). Quaest. Ent. 11: 505-576. Back, E. A. 1904. New species of North American Asili- dae. Canadian Ent. 36: 289-293. 1909. Therobberfliesof America north of Mexico, belonging to the subfamilies Leptogastrinae and Dasypogoninae. Trans. Amer. Ent. Soc. 35; 137-400. Banks. N 1920. Descriptions ofa few new Diptera. Cana- dian Ent. 52: 65-67. Bellardi, L. 1861. Saggio di ditterologia messicana. Parte II. Torino. Bigot, J. M. F. 1878. Dipteres nouveaux ou pen connus. Tribu des Asilidi. Ann. Soc. Ent. France Ser. 5, 8: 31-48, 40-48, 213-240, 401-446. Bromley, S. W 1928. Notes on the genus Proctacanthus with descriptions of two new species (Diptera: Asilidae). Psyche 35: 12-15. 1931. New Asilidae, with a revised key to the genus Stenopogon Loew: (Diptera). Ann. Ent. Soc. Amer. 24: 427-435. 19.34. The robber flies of Texas (Diptera, Asilidae) Ann. Ent. Soc. Amer. 27; 74-111. 1936. The genus Diogmites in the United States of America with descriptions of new species (Diptera; Asilidae). J. New York Ent. Soc. 44; 225-237. 1937a. The genus Stenopogon Loew in the United States of America (Asilidae; Diptera). J. New York Ent. Soc. 45; 291-309. 1937b. New and little-known Utah Diptera with notes on the taxonomy of the Diptera. Proc. Utah Acad. Sci. 14:99-109. 1940. New U.S.A. robber flies (Diptera; Asilidae). Bull. Brooklyn Ent. Soc. 35; 13-21. 1951. Asilid notes (Diptera) with descriptions of 32 new species, Amer. Mus. Novitates 1532: 1-36. Brown, B. 1897. Two new species of asilids from New Mexico. Kansas Univ. Quart. Ser. A, 6: 103. Brown. C. J D. 1929. A morphological and systematical study of Utah Asilidae (Diptera). Trans. Amer. Ent.' Soc. 54; 295-320. Cole, F R 1923. Expedition of the California Academy of Sciences to the Gulf of California in 1921. The Bombyliidae (bee flies); Diptera from the islands and adjacent shores of the Gulf of California. II. General report. Proc. California Acad. Sci., Ser. 4, 12: 289-314. Cole, F. R., and A. L. Lovett. 1919. New Oregon Diptera. Proc. California Acad. Sci., Ser. 4, 9; 221-255. 1921. An annotated list of the diptera (flies) of Oregon. Proc. California Acad. Sci., Ser. 4, 11: 197-344. Cole, F. R., and A. E. Pkitchard 1964. The genus Mal- lophora and related asilid genera in North Amer- ica (Diptera: Asilidae). Univ. California Publ. En- tomol. 36:43-100. Cole, F. R, and J. Wilco.x. 1938. The genera Lasiopogon Loew and Alexiopogon Curran in North America (Diptera: Asilidae). Ent. Americana 18; 1-90. CoQUlLLETT, D. W 1893. A new asilid genus related to Erax. Canadian Ent. 25; 175-177. 1904. New North American Diptera. Proc. Ent. Soc. Washington 6: 166-192. Curran, C H 1922. New Diptera in the Canadian Na- tional Collection. Canadian Ent. 54: 277-287. 1923a. Studies in Canadian Diptera. I. Revision of the asilid genus Cijrtopogon and allied genera. II. The genera of the family Blepharoceridae. Cana- dian Ent. 55; 92-95, 116-125, 132-142, 169-174, 185-190, 266-269. 1923b. Apparently undescribed Canadian Asilidae and Dolichopodidae (Diptera). Canadian Ent. 55: 207-211. 1926. A new species of Comantclla (Asilidae, Diptera). Canadian Ent. 58; 310-312. 1927. Descriptions of Nearctic Diptera. Canadian Ent. 59: 79-92. 1930. New Diptera from North and Central Amer- ica. Amer. Mus. Novitates 415; 1-16. 1934. The families and genera of North American Diptera. New York. 512 pp. HiNE. J S 1906. Two new species of Diptera belonging to Asilinae. Ohio Nat. 7; 29-30. 1908. Two new species of Asilidae from British Columbia. Canadian Ent. 40; 202-204. 1909. Robber flies of the genus A.St/us . Ann. Ent. Soc. Amer. 2; 136-172 (= contributions from the Ohio State Univ. Dept. Zool. and Ent. No. 32). 1911. Robber flies of the genera Promachus and Proctacanthus . Ann. Ent. Soc. Amer. 4: 153-172 (= contributions from the Ohio State Univ. Dept. of Zool. and Ent. No. 33). 1916. Descriptions of robber flies of the genus Erax. Ohio Jour. Sci. 17: 21-22. 1918. Descriptions of seven species of A.si/H.s (fam- ily Asilidae). Ohio Jour. Sci. 18; 319-322. 1919. Robber flies of the genus Erax. Ann. Ent. Soc. Amer. 12; 103-154 (= contributions from the Ohio State Univ. Dept. of Zool. and Ent. No. 57). Hull, F M. 1957. Some new species of robber flies (Diptera: Asilidae). Psyche 64; 70-75. James, M. T. 1937a. New Colorado Asilidae (Diptera). Ent. News 48; 12-15. 1937b. The genus Comantella Curran (Diptera; Asilidae). Pan-Pac. Ent. 13: 61-63. 1941. The robber flies of Colorado (Diptera; Asili- dae). J. Kansas Ent. Soc. 14; 27-53. 1942. Additions to the "Robber Flies of Colorado." J. Kansas Ent. Soc. 15; 124-126. Johnson, C W 1918. Notes on the species of the genus Dioctria. Psyche 25; 102-103. Johnson. D E 19.36. A further study of Utah Asilidae. Unpublished thesis, Brigham Young University, Provo, Utah. Great Basin Naturalist Vol. 47, No. 1 •i • A Stenopogon mexicanus Stenopogon utahensis ./■ / '• "fe^ 129 tJIfeei:: "^ 'S- Stenopogon rufibarbis 130 4r ^ ©■ #Stlchopoqon fraqil is I Stichopogon sal inus Astichopoqon trifasciatus '-'," '*?;- Y Tiracticus ruficaudu 7V':?--"f Il3ir^ h£l ^i^* M: :'i^«:-'. 9^' ' ^; Wilcoxia painteri 132 Figs. 129-132. Utah Asilidae, distribution: 129, Stenopogon mexicanus dnd Stenopogon utahensis . 1.30, Stenopogon rufibarbis; 131, Stichopogon fragilis , Stichopogon salinus , Stichopogon trifasciatus , and Taracticus ruficaudus ; 132, Wilcoxia painteri . January 1987 Nelson: Utah Robber Flies 89 1942. A new Cijrtopogon (Asilidae, Diptera) from Utah. Great Basin Nat. 3: 1-4. 1958. A new species oiMallophora from the Great Salt Lake Desert (Diptera: AsiHdae). Great Basin Nat. 18: 41-42. Knowlton, G. F., and F C Harmston 1938. Utah Asih- dae. Proc. Utah Acad. Sci. 15: 123-125. Knowlton, G. F.. F. C. Harmston, and G. S. Stains. 1939. Utah Diptera. Mimeo Ser. 200 (Tech.) 5: 4-5. Linnaeus, G. 1758. Systema naturae per regna tria natu- rae. Ed. 10. Stockhohn. 824 pp. 1763. Amoenitates Academicae, sen disserta- tiones variae physicae, medicae, botanicae, ante- hac seorsim editae, nunc collectae et auctae cum tabuUs aeneis. Vol. 6. Stockhohn. 486 pp. LOEW, H. 1866. Diptera Americae septentrionahs indi- gena. Genturia septima. BerHner Ent. Zeitschr. 10: 1-54. 1874. Neue nordamerikanshe Dasypogonina. Ber- hner Ent. Zeitschr. 18: 353-377. MacQUART, J. 1834. Histoire naturelle des insectes. Diptera. Vol. 1. Paris. 578 pp. (Gollection des suites a Buffon) [q.v.]. 1838. Diptereexotiques nouveau.xou peuconnus. Soc. Rov. des Sci., de I'Agr. et des Arts, Lille, Mem. 1838 (2): 9-225. Martin, G. H. 1957. A revision of the Leptogastrinae in the United States (Diptera: Asilidae). Bull. Amer. Mus. Nat. Hist. 111:347-385. 1959. The Holopogon complex of North America, excluding Mexico, with the descriptions of a genus and a new subgenus (Diptera: Asilidae). Amer. Mus. Novitates 1980: 1-40. 1962. The mistaken identity of Proctacanthus arno Townsend and a new species (Diptera: Asili- dae). J. Kansas Ent. Soc. 35: 185-188. 1968. A revision of Ospriocerus (Diptera: Asili- dae). Proc. Galifornia Acad. Sci. 35: 401-424. 1975. The generic and specific characters of four old and six new Asilini genera in the western United States, Mexico, and Central America (Diptera: Asilidae). Occ. Pap. Galifornia Acad. Sci., No. 119. 107pp. McAtee, W L 1919. Key to the Nearctic species of the genus Laphria (Diptera: Asilidae). Ohio Jour. Sci. (1918)19:143-172. Melander, A. L 1923a. The genus Cijrtopogon (Diptera: Asilidae). Psyche 30: 102-119. 1923b. The genus Lasiopogon (Diptera: Asilidae). Psyche 30: 135-145. 1923c. Studies in Asilidae (Diptera). Psyche 30: 207-219. Osten Sacken, G. R 1877. Western Diptera: Descrip- tions of new genera and species of Diptera from the region west of the Mississippi and especially from California. U.S. Dept. Interior Geol. and Geog. Survey of the Terr., Bull. 3: 189-354. 1887. Diptera. Pages 129-216 in F. D. Godman and O. Salvin, eds., Biologia CentraH-Americana [q.v.]. Zoologia-Insecta-Diptera. Vol. 1. London. 378 pp. Papavero, N . and N Bernardi. 1973. Studies of Asilidae (Diptera) systematics and evolution. 111. Tribe Blepharepiini (Dasypogoninae). Arq. Zool., Sao Paulo 24: 163-209. Pritcmard, a E 1935. New Asilidae from the southwest- ern U.S. (Diptera). Amer. Mus. Novitates 813: 1-13. 1938. The genus Hodoplnjlax James, with a de- scription oi hasingeri , new species (Diptera: Asili- dae). Pan-Pac. Ent. 14: 129-131. 1943. Revision of the genus Cophura Osten Sacken (Diptera: Asilidae). Ann. Ent. Soc. Amer. 36: 281-309. Say.T 1823. Descriptions of dipterous insects of the U.S. J. Acad. Nat. Sci. Phila. 3: 9-54, 73-104. 1824. Appendix, Part 1. Natural History. 1. Zool- ogy. E. Class Insecta. Pages 268-278 in W. H. Keating, Major Long's second expedition [q.v.]. Vol. 2. Philadelphia. 459 pp. SCHAEFFER, C. 1916. New Diptera of the family Asilidae with notes on known species. J. New York Ent. Soc. 24: 65-69. SCHINER, I. R. 1867. Neue oder weniger bekannte Asili- den der K. zoologischen Hofcabinetes in Wien. K.;K. Zool.-Bot. Gesell. Wien, Verhandl. 17 (Ab- handl): 355-412. Stone, A., C. W. Sabrosky, W W Wirth, R H Foote, and J, R. CouLSON 1965. A catalog of the Diptera ofAmerica north of Mexico. U.S. Dept. Agr., Agr. Res. Serv., Washington, D.C. 1696 pp. (Asilidae, pp. 360-401, 1113-1116). Tucker, E. S. 1907. Some results of desultory collecting of insects in Kansas and Colorado. Kansas Univ. Sci. Bull. 4 ( = whole ser., 14): 51-112 [ = Kansas Univ. Bull. 7(5)]. Walker, F 1849. List of the specimens of dipterous insects in the collection of the British Museum. Four parts and three supplements. London. Pt. 2: 231-484. 1851. Insecta saundersiana; or characters of unde- scribed insects in the collection of William Wilson Saunders, Esq. in 5 parts. 474 pp. WiLCO.X, J 1935. New asilid flies of the genus Ablautus with a key to the species. Canadian Ent. 67: 222-227. 1936a. A new robber fly, with a key to the species oiCallinicus and Chrysoceria . (Diptera: Asilidae). Ent. News 47: 208-210. 1936b. Asilidae, new and otheiAvise, from the Southwest, with a key to the genus Stichopogon . Pan-Pac. Ent. 12: 201-212. 1941. New Heteropogon with a key to the species (Diptera: Asilidae). Bull. Brooklyn Ent. Soc. 36: 50-56. 1946. New Nicocles with a key to the species (Diptera: Asilidae). Bull. Brooklyn Ent. Soc. 40: 161-165. 1960. Laplu/stia Loew in North America (Diptera: Asilidae). Ann. Ent. Soc. Amer. 53: 328-346. 1964. The genus Metapogon (Diptera: Asilidae). Pan-Pac. Ent. 40: 191-200. 1965. New Heteropogon Loew, with a key to the species and the description of a new genus (Diptera: Asilidae). Bull. S. Galifornia Acad. Sci. 64: 207-222. 1966a. Ej^cnflCoquillett in America north of Mex- ico. (Diptera: Asilidae). Proc. Galifornia Acad. Sci. 34: 85-234. 90 Great Basin Naturalist Vol. 47, No. 1 1966b. New species and a key to the species of Saropo^on Loew (Diptera; Asilidae). Pan-Pac. Ent. 42: 127-136. 1966c. New species and keys to the species of Ablautits Loew and Omniablatitits Pritchard (Diptera; AsiUdae). Canadian Ent. 98: 637-682. 1966d. New species of Haplopo^on Engel with a key to the species (Diptera: Asihdae). Bull. S. Cahfornia Acad. Sci. 6.5: 99-106. 1971. The genera Sfenopogon Loew and Scleropogon Loew in America north of Mexico (Diptera: Asilidae). Occ. Pap. California Acad. Sci., No. 89. 1.34 pp. 1972a. The genus Sintoria Hull (Diptera: Asilidae) Pan-Pac. Ent. 48: 51-58. 1972b. New species of robber flies of the genera Wilcoxia and Metapogon (Diptera: Asilidae). Bull. S. California Acad. Sci. 71: 43-47. Wilcox, J , and C H Martin. 1936. A review of the genus Cyrtopogon Loew in North America (Diptera: Asilidae). Ent. Americana. 16: 1-94. WiLLlSTON, S W 1883. On the North American Asilidae (Dasypogoninae, Laphriinae), with a new genus of Syrphidae. Trans. Anier. Ent. Soc. and Acad. Nat. Sci. Phila., Ent. Sect. Proc. (1884) 11: 1-35. 1885. On the North American Asilidae (Part II). Trans. Amer. Ent. Soc. and Acad. Nat. Sci. Phila., Ent. Sect. Proc. 12: 53-76. 1893. List of Diptera of the Death Valley Expedi- tion. Pages 2.53-2.59 in C. V. Riley, The Death Valley Expedition. A biological survey of parts of Calif, Nev., Ariz., and Utah. Part II. r. Report on a small collection of insects made during the Death Valley Expedition. North Amer. Fauna 7: 235-268. Wood, G C. 1981. Asilidae. Pages 549-573 in J. F. McAlpine, B. V. Peterson, G. E. Shewell, H. J. Teskey, J. R. Vockeroth, and D. M. Wood, Man- ual of Nearctic Diptera. Vol. 1. Research Branch Agriculture Canada Monograph No. 27. 674 pp. ELEMENTAL COMPARTMENTALIZATION IN SEEDS OF ATRIPLEX TRIANGULARIS AND ATRIPLEX CONFERTIFOLIA M. A. Khan', D. J. Weber, and VV. M. Hess" AbstraCT — Seeds of two halophytes, Atriplcx trianfiiilaris, which grow.s in a niesic saUne marsh environment, and Atriplex confer-tifolia, which grows in a xeric desert environment, were analyzed by energy-dispersive X-ray micro- analysis for the distribution of elements. The highest concentration of sodium, chlorine, potassium, and calcium was present in seed coats of A. triangularis. All of the elements detected were at low concentrations in the endosperm. Embryos contained the highest amount of phosphorus that is probably associated with organophosphate compounds. Potassiiun was also high in embryos. The total amoiuit of elements in all regions of A. confertifolia was low as compared to A. triangularis. In a similar pattern sodium, chlorine, potassium, and calcium were the highest in seed coats of A. confertifolia. Elemental concentration was also low in the endosperm. Likewise, the phosphorus level was the highest in the embryo. The results support the concept of elemental compartmentalization in seeds of these halophytes. Halophytes are plants that grow and com- plete their life cycles in habitats of high salin- ity. Although Atriplex spp. do not require other than trace amounts of Na^ for normal growth, they frequently grow better in the presence of NaCl (Osmond et al. 1980). Atriplex spp. from different environments are characterized by high levels of NaCl in shoots, particularly in halophytes of arid shrublands (Hansen and Weber 1975, Osmond et al. 1980). However, few reports are available on the status of ions present in Atriplex seeds. Ungar (1984) reported that the ions of seeds of Atriplex triangularis constitute 2% of the total dry weight as compared to about 14% in leaves. He suggested that halophytes regulate ion distribution so that the ion concentration in seeds is low. Several studies have been done on the distribution of elements in seeds of glycophytes (Lott et al. 1982, Tanaka et al. 1977, Hofsten 1973). However, little informa- tion is available on the ion compartmentaliza- tion within different parts of seeds of halo- phytes. Other plant parts of glycophytes have been studied using energy-dispersive X-ray microanalyses (Bennett and Wynn Parry 1981, Saka 1982, Strullu et al. 1981). There- fore, the purpose of this investigation was to determine the elemental distribution in the seeds of these two halophytes {Atriplex spp.) grown in different saline environments. A clear understanding of the type and dis-tribu- tion of elements is needed to understand the factors involved in seed germination of halo- phytic plants. Materials and Methods Seeds oi Atriplex triangularis Willd. were collected from a salt marsh at Rittman, Ohio, and seeds oi Atriplex confertifolia (Torr. and Frem) S. Wats were obtained from Howard Stutz (Brigham Young University), who col- lected them from the desert areas of central Utah. These seeds were sectioned with razor blades and mounted on carbon stubs with graphite glue. Energy-dispersive X-ray mi- croanalysis (EDS) was conducted with an EDAX 9100/70 with auto-calibration for auto- mated analysis. The background was sub- tracted automatically. The X-ray analysis sys- tem was interfaced with an AM Ray, 1000 A SEM. The seeds were not coated since the coating interferes with EDS analyses. The ac- celerating voltage for analysis was 20 Kv, the beam current was 75 uA, and analysis times were 100 sec at about 3,000 cps. The take-off angle was 45° with respect to the cut surface. Four different seeds for each species were analyzed in three different regions. Each re- gion of each seed was analyzed four times at four different locations to provide a statistical basis for determining variability. Oneway ANOVA and Fischer's LSD multiple com- parison tests were used for statistical analyses. Department of Botany, University of Karachi .32. Pakistan. "Department of Botany and Range Science. Brigham Young University, Provo, Utah 84602. 91 92 Great Basin Naturalist Vol. 47, No. 1 Figs. 1-2. Atriplex triangularis: 1, Scanning electron micrograph of a cross section of an uncoated seed showing the embryo (E), endosperm (EN), and seed coat (SC), 120X; 2, Scanning image of X-ray signals for chlorine (white image) of the same cross section of the seed shown in Fig. 1, 120X. Results Results obtained with both species of Atriplex are shown in Figures 1-4. Higher concentrations of some elements were present in A. triangularis seed coats and em- bryos than in seed coats and embryos of A. confertifolia, but endosperms of seeds of both species were low in all elements. There were no significant differences in elemental content of the endosperm of the two species. Sodium, chlorine, and calcium in the seed coats of A. triangularis were significantly higher (5% level) than in the endosperm and embryo. On the other hand, the elements that were higher (5% level) in the embryo than in the seed coat were magnesium, aluminum, phosphorus, and sulfur. Potassium was signif- icantly different in seed coats and embryos as compared to the endosperm. A. confertifolia seeds contained more potassium and calcium in the seed coat (5% level) than in the embryo. The highest con- centration of phosphorus was in the embryo (5% level), and the amount of potassium in the embryo and seed coat was significantly higher (5% level) than in the endosperm. Discussion The regions of the seed studied not only differed in elemental composition but also in relative concentrations. A comparison of these two halophytic plants indicates the con- centrations of elements present in A. triangu- laris seeds were much higher than in A. con- fertifolia seeds, particularly chlorine and potassium. The high concentrations of potas- sium may be related to the large number of enzymes where potassium is a cofactor (Wyn- Jones and Pollard 1983). Khan and Ungar (1984) reported that seeds of A. triangularis collected from a salt marsh at Rittman, Ohio, where soil salinity was about 3%, have sodium and chlorine concen- trations in seeds ranging from 0.7 to 2% of the dry weight. The concentrations of these ele- ments after analysis with X-ray microanalysis (Fig. 3) are much lower considering the fact that ionic content of leaves of A. triangularis may be 15% in plants growing in 3% salinity (Ungar 1984). Seeds of Salicornia europaea have 0.77% sodium as compared to 14.8% sodium in other parts of the plant (Poulin et al. 1978). Hocking (1982) reported that seeds of January 1987 Khan et al: Atriplex Seeds 93 400 T 300 •• Atriplex triangularis Seed Coat net CPS 200 ■• 100 •■ 400 T 300 •■ net CPS 200 + 100 •■ Elements Endosperm 400 T 300 ■• Na Mg Al Si P S Elements I I CI K Ca Embryo net CPS 200 + 100 •• Na — B — B B M,B._. Mg Al Si P S CI K Ca Elements Fig. 3. Distribution of nine elements in the seed coat, endosperm, and embryo of Atriplex triangularis as determined by energy-dispersive X-ray microanalysis. Data is in net coinits per second. 94 Great Basin Naturalist Vol. 47, No. 1 400 T 300 •• net CPS 200 100 ■■ 400 T 300 •■ net CPS 200 + 100 •■ Atriplex confertifolia Seed Coat Na Mg Al Si P S CI K Ca Elements Endosperm 400 T Na Mg Al 300 •• net CPS 200 •• 100 ■■ Si P S CI Elements Ca Embryo CI K Ca Fig. 4. Distribution of nine elements in the seed coat, endosperm, and embryo of Atriplex confertifolia as determined by energy-dispersive X-ray microanalysis. Data is in net counts per second. January 1987 Khan etal.:Atriplex Seeds 95 Cakile maritima have a sodium content of 0.02% and a chlorine concentration of 0.07% compared to 14. 1% chlorine and 6.8% sodium in leaves. Thus, the pattern of elemental dis- tribution of these two species of Atriplex is consistent with these reports. Lott et al. (1982) observed low calcium content in the endosperm and embryo of castor bean seeds. The calcium level was also very low in the endosperm and embryo in both Atjiplex seeds that we analyzed. The concentration of elements in embryos was higher in A. triangularis seeds than in A. confertifolia seeds, which suggests that desert plants do not absorb or store as many ele- ments in seeds as do salt marsh plants. These results indicate that the Atriplex species stud- ied were able to compartmentalize sodium and chlorine in seed coats but reduce the levels of sodium and chlorine in embryos of their seeds. Similar results were obtained with seeds o( Salic or 7iia pacifica and Atriplex canescenshy Khan, Weber, and Hess (1985). Acknowledgments We appreciate the cooperation of Howard Stutz in providing the seeds oi Atriplex con- fertifolia. This research was supported by a grant from the National Science Foundation No. 8403768. Literature Cited Bennett, D M.. and D Wynn Parry 1981. Electron- probe microanalysis studies of silicon in the epi- carp hairs of the caryopses of Hordeum sativum Jess., Avena sativa L. , Secale cereale L. and Triticum aestivum L. Ann. ofBot. 48: 645-654. Hansen, D J , and D J. Weber 1975. Environmental factors in relation to the salt content of Saliconiia pacifica var. utahensis. Great Basin Nat. 35: 86-96. HoCKiNc;. P J 1982. Salt and mineral nutrient levels in fruits of two strand species, Cakile maritima and Arctothcca populifolia, with special reference to effect of salt on the germination ofCakile. Ann. of Bot. 50: 335-343. Hofsten, A. V. 1973. X-ray analysis of microelements in seeds of Crambe abyssinica. Physiol. Plant. 29: 76-81. Khan, M. A., and 1. A. Ungar. 1984. Seed polymorphism and germination responses to salinity stress in Atriplex triangularis Willd. Bot. Gaz, 145: 487- 494. Khan, M A , D J Weber, and W. M Hess 1985. Ele- mental distribution in seeds of the halophytes Sal- icornia pacifica var. utahensis and Atriplex canes- cens. Amer. J. Bot. 72: 1672-1675. Lott, J N A., J. S. Greenwood, and C. M. Voolmer. 1982. Mineral reserve in castor beans: the dry seed. Plant Physiol. 69: 829-9.33. Osmond, C B , O Bjorkman, and D J. Anderson 1980. Pages 154-190 in Physiological processes in plant ecology. Springer-Verlag, Berlin. PouLiN, G , D BouRQUE, S Eh), and K Jankowski 1978. Composition chimique de Saliconiia europaea L. Naturaliste Canadien 105: 473-478. Saka, S. 1982. A study of lignification in loblolly pine tracheids by the SEM-EDAX technique. Science Technol. 16: 167-179. Strullu, D G., J P GouRRET, J. P Garrec, and a FouRCY 1981. Ultrastructure and electron-probe microanalysis of the metachromatic vacuolar gran- ules occurring in Taxtis mycorrhizas. The New Phytol. 87: 537-545. Tanaka, K., M. Ogawa, and Z Kasai 1977. The rice scutellum. II. A comparison of scutellar and aleuron electron-dense particles by transmission electron microscopy including energy-dispersive X-ray analysis. Cereal Chem. 54: 684-689. Ungar, I. A 1984. Autecological studies with Atriplex triangularis Willdenow. Pages 40-52 in A. R. Tiedemann, E. D. McArthur, H. C. Stutz, R. Stevens, and K. L. Johnson, eds., Biology of Atriplex and related chenopods. Symposium, US DA, Interniountain Forest and Range E.xperi- mental Station, Ogden, Utah. Wyn-Jones, R G.. and a Pollard 1983. Proteins, en- zymes and inorganic ions. Pages 528-562 in A. Lauchli and R. L. Bieleski, eds.. Encyclopedia plant physiology. Vol. 15. New York. PLANT COMMUNITY CHANGES WITHIN A MATURE PINYON-JUNIPER WOODLAND' Dennis D. Austin^ Abstract. — Vegetal composition was determined during 1974 and 1984 using 60 permanent 50 m" plots within a mature pinyon-juniper community in northeastern Utah. Results indicated that not only was there little significant change in community composition, but with many species frequency and density remained nearly the same during the decade. Pinyon-juniper woodlands occur on over 325,000 km" of the intermountain region and comprise a major habitat for big game on win- ter ranges. However, forage productivity and variety seldom remain near optimum levels since tree density and canopy cover gradually increase with age, while understory vegeta- tion decreases (West et al. 1979). Grazing by livestock or big game accelerates loss of un- derstory vegetation and ground cover result- ing in a further decrease of grazing capacity and increased soil erosion (Baxter 1977). Thus, a need for periodic tree control in pinyon-juniper stands is evident if maximum grazing is an objective. This paper presents data indicating little successional change of a plant community within a mature pinyon-ju- niper woodland during a 10-year period. Methods In conjunction with other studies (Austin and Urness 1976, Austin et al. 1977), 60 per- manent plots were established at the foot of the Blue Mountain Anticline in the Miners Draw area of northeastern Utah in Uintah County. Plots were distributed in the zone dominated by pinyon-juniper between 1,650 and 1,850 m elevation. To insure that plots could be found in subsequent years, plot loca- tions were preselected at specific distances and directions from evident landmarks using topographic maps and aerial photographs. Each plot was rectangular, measured 5.5 x 9. 1 m, and was marked by steel reinforcement rods on all corners. Plots were established and initial data col- lected during early summer 1974, with data comparably collected in 1984. In sampling, plot boundaries were defined by connecting the four corners with a string. All perennial plants within the plot were counted and recorded by species. To assure that individual plants were not missed on these large plots, a separate search was made for every perennial species, previously identified in the area, on each plot. Each plot was then searched for annual species as a group. Individual species were recorded as present, but individuals were not counted. Also recorded were maxi- mum height and mean crown diameter, mea- sured along the north-south and east-west axes, of juvenile (31-120 cm height) trees of pinyon pine {Finns ednlis) and Utah juniper (Jnniperns osteosperma) and shrubs of low sagebrush {Artemisia arhuscnla), big sage- brush {Artemisia tridentata), and birchleaf mahogany (Cercocarpns montanus). Data were analyzed using the standard and paired t-tests with a significance level of p < .05. Results and Discussion Few significant changes were found to oc- cur during the 10-year period (Table 1). Only three species, needle and thread (Stipa co- mata), Fendler spring parsley {Cijmopterns fendleri), and thickstem wild cabbage {Caidanthus crassicaidis), showed a signifi- cant decrease while only broom snakeweed {Gutierrezia sarothrae) showed a significant ^This report is a contribution of Utah State Division of Wildlife Resources, Federal Aid Project \V-105-R. -Utah Division of Wildlife Resources, Department of Range Science, Utah State University, Logan, Utah 84322. 96 January 1987 Austin: Plant Ecology Table 1. Number of plants per 60 permanent 50 m^ plots and frequency of occurrence in ( ). 97 Trees Juniperus osteosperma (Torr.) mature juvenile seedling Pinus edulis (Engelm.) mature juvenile seedling Shrubs Artemisia arhiiscula (H. & C.) Artemisia tridentata (Nutt.) Atriplex canescens (Pursh) Atriplex confertifolia (Torr. & Freni) Cercocarpus montanus (Raf. ) Ephedra nevadensis (S. Wats.) Ephedra viridis (Coville) Eriogonum microthecum (Nutt.) Forsellesia meionandra (Kochne) Graijia spinosa (Hook.) Gutierrezia sarothrae (Pursh.) ' Artemmisia spp. (dead skeletons) Total (Live shrubs) ~ ' Grasses-Perennial Aristida longiseta (Stend.) Distichlis stricta (Torr.) Orijzopsis hymenoides (R. & S.) Poa secunda (Presl.) Sitanion hystrix (Nutt.) Stipa comata (Trin. & Rupr.) Total Grasses-Annual Bromus tectorum (L.) Festuca octoflora (Walt.) Total Forbs-Perennial Arenaria fendleri (A. Gray) Aster arenosus (Blake) Caulanthus crassicaulis (Torr.) " Cryptantha spp. Cymopterus fendleri (A. Gray)" Echinocactits simpsonii (Engelm.) Erigeron spp. Eriogonum ovalifolium (Nutt.) Erysimum asperum (D.C.) Gilia congesta (Hook.) Hymenoxys richardsonii (Hook.) Linum lewesii (Pursh) Lithospermum ruderale (Dougl.) Lygodesmia grandiflora (Nutt.) Machaeranthera grindeloides (Nutt.) Mamillaria tetrancistra (Engelm.) Opuntia spp. (number of pads) Penstemon spp. Petradoria pumila (Nutt.) Phlox hoodii (Richards) Physaria chambersii (Rollins) Senecio multilobatus (T. &G.) Sisymbrium linifolium (Nutt.) Townsendia incana (Nutt.) 1974 1984 272 (59) 271 (59) 44 (23) 53 (27) 39 (25) 42 (26) 22 (12) 23 (12) 13 (5) 11 (7) 53 (20) 65 (20) 154 (14) 185 (12) 70 (13) 67 (13) 2 (1) 1 (1) 3 (2) 1 (1) 8 (4) 9 (5) 4 (1) 4 (1) 166 (22) 168 (24) 30 (10) 44 (10) 2 (1) 2 (1) 2 (1) 1 (1) 302 (26) 703 (30) 502 (32) 435 (32) 743 (46) 1185 (51) 23 (3) 24 (3) 42 (1) 63 (1) 14 (5) 6 (2) 92 (23) 111 (26) 199 (37) 301 (43) 4 (4) 1 (1) 374 (49) 506 (50) (22) (53) — (4) — (7) (24) (53) 9 (2) 4 (1) 1451 (24) 1502 (24) 62 (9) 21 (5) 408 (44) 692 (46) 11 (4) 2 (1) 22 (4) 34 (2) 5 (4) 8 (2) 23 (9) 28 (9) 1033 (48) 782 (53) 252 (32) 153 (31) 37 (3) 32 (3) 36 (3) 21 (5) 8 (3) 3 (1) 3 (1) 0 (0) 91 (13) 120 (16) 1 (1) 2 (1) L1679 (50) 10304 (50) 197 (38) 367 (43) 377 (10) 347 (10) 4 (1) 2 (2) 51 (16) 71 (14) 46 (6) 23 (7) 867 (16) 1033 (33) 189 (36) 120 (32) 98 Great Basin Naturalist Vol. 47, No. 1 Table 1 continued. Forbs-Perennial continued Tragopogon diibius (Scop.)^ Total Forbs-Annual Camelina microcarpa (Angrz.) Chenopodium spp. Eriogonwn cernuum (Nutt.) Eriogonum nutans (T. & G.) Salsola kali (L.) Streptantella longirostris (S. Wats. Others Total 1974 1984 6 (3) 0 (0) 16868 (60) 15671 (60) _ (1) (5) — (2) — (2) — (2) — (1) — (3) — (2) — (2) — (2) — (6) — (7) — (13) — (12) (25) (25) Defined by height: Mature = 121 + cm. Juvenile = 31-120cm, seedHng 0-;30cin "Plant numbers significantly different between 1974 and 1984 standard t-test (p < ,0.5)- Plant numbers significantly different between 1974 and 1984 paired t-test (p s .0.5). increase using the standard t-test. However, because of the small number of plants found, only the broom snakeweed was significant us- ing the paired t-test. These data clearly showed that the plant community exhibited little change during the decade. The number of mature trees remained the same with a combined density of 980 trees per hectare in both 1974 and 1984 (Table 1). Mean yearly height and crown diameter growth of juvenile Utah juniper were 1.8 and 1.4 cm, respectively, and for pinyon pine 1.2 and 1.0 cm, respectively. Except for broom snakeweed, numbers of shrubs by species did not change. Dead skele- tons of sagebrush {Artemisia spp.) were counted to possibly detect a change in density from the community prior to 1974. Although the change in dead sagebrush was also in- significant, it is interesting to note that in 1974 the ratio of dead to live sagebrush was 2.2:1.0 and 1.7:1.0 in 1984. Since numbers of live sagebrush plants showed little change, these data suggest sagebrush was more abundant prior to 1974. Mean yearly height and crown diameter growth for low sagebrush were 0.3 and 1.3 cm, respectively; big sagebrush aver- aged 0.6 and 1.4 cm, and birchleaf mahogany grew 3.0 and 2.3 cm, respectively. Sagebrush growth was slow but comparable to tree growth, whereas birchleaf mahogany, al- though found in only a few areas, did some- what better. The total number of live shrubs showed a significant change mostly because of the increase in broom snakeweed. Perennial grasses and forbs showed little change (Table 1). With reference to occur- rence, 8 perennial species repeated the same frequency, 13 decreased, and 10 increased. The total number of perennial forbs counted did not statistically change. Excluding prickly pear (Opiinfia spp.), 5,189 and 5,367 forbs were counted in 1974 and 1984, respectively. Even though annual grasses were found on more plots in 1984, annual forbs retained a low level of frequency. Although this study did not show a chang- ing trend in the understory plant community, many studies have determined an inverse re- lationship between density or crown cover of trees and understorv production (Jameson 1967, Pieper 1977, Tausch and Tueller 1977). Since pinyon and juniper trees are more effi- cient competitors for soil moisture than un- derstory vegetation, a decrease in the under- story is predictable with time (West 1984). Consequently, a constant reduction of under- story vegetation can be expected on disturbed sites as soon as a tree species is reestablished. From the standpoint of big game values on winter range, these data indicate the study site carrying capacity of the mature pinyon- juniper woodland was unchanged over a 10- year period or changing at such a rate as to be statistically undetected. Even though little change in carrying capacity can therefore be predicted, it must be realized that carrying capacity was already low. Austin and Urness (1975) reported a winter deer density on the study area of about .07 deer/ha and believed the population was near carrying capacity. Treatment of the pinyon-juniper stand as pre- viously recommended (Austin and Urness 1975) into small blocks of cleared woodland is needed if increased wildlife and livestock grazing capacities are desirable. Without January 1987 Austin: Plant Ecology 99 treatment no change or only slow changes can be predicted in understory vegetation accom- panied by increased soil erosion and loss of site productivity potential (West 1984). Literature Cited Austin, D. D , and P. J. Urness 1975. The effects of winter game range rehabilitation upon a innle deer herd. Utah Div. Wildl. Res. Final Rep. Proj. W-105-R, JobA4r. 30 pp. 1976. Small mammal densities related to understorN' cover in a Colorado plateau pinyon-juniper forest. Utah Acad. Sci., Arts, and Letter.s'Proc. 53; 5-12. Austin, D. D . P. J. Urness, ,\nd M. L. Wolfe 1977. The influence of predator control on two adjacent win- tering deer herds. Great Basin Nat. .37: 101-102. Baxter, C. 1977. A comparison between grazed and un- grazed juniper woodland. Pages 25-27 in USDA, Forest Service, General Technical Report RM-39. Jameson, D. A. 1967. The relationship of tree overstory and herbaceous understory vegetation. J. Range Manage. 20: 247-249. PiEPER, R. D. 1977. The southwestern pinyon-juniper system. Pages 1-7 in USDA, Forest Service, Gen- eral Technical Report RM-39. Tausch, R. J , AND P T. TuELLER 1977. Plant succession follows chaining of pinyon-juniper woodland in eastern Nevada. J. Range Manage. 30: 44-49. West, N E 1984. Successional patterns and productivity potentials of pinyon-juniper ecosystems. Pages 1201-1332 in National Research Council/National Academy of Science, Developing strategies for rangeland management. Westview Press, Boul- der, Colorado. West, N E , R J Tausch, and A. A. Nabi. 1979. Patterns of pinyon-juniper invasion and degree of suppres- sion of understory vegetation in the Great Basin. USDA, Forest Sei"vice, Range Improvement Notes. Ogden, Utah. 18 pp. CONSUMPTION OF FRESH ALFALFA HAY BY MULE DEER AND ELK' Dennis D. Austin" and Philip J. Urness" Abstract — Tame mule deer and elk were fed fresh alfalfa hay at night and given various alternate forages during the day. This schedule, simulating farmland depredation feeding, yielded consumption values for field-growing alfalfa hay. Depredation of standing alfalfa by big game was recognized as a problem before 1930 when deer began using summer fields in southern Utah. Use of winter haystacks in northern and central Utah was first recorded about 1930 (Low 1955). To ameliorate at least part of the problem, the Utah Division of Wildlife Resources (UDWR), formerly the Utah Fish and Game Department, began providing materials and/or building fences around highly impacted winter haystacks. As big game populations increased, so also did the depredation problem. In 1947 the legislature passed Utah's first wildlife damage law. This legislation was designed to reduce the economic losses incurred to farmers and permitted UDWR to pay for big game depre- dation losses up to a maximum payment of $100 per year per landowner. More impor- tantly, however, the law clearly indicated that the state of Utah, through UDWR, accepted at least part of the responsibility for depreda- tion losses. The maximum payment was in- creased to $200 in 1953 and abruptly raised to $2,000 in 1977. An amendment considered in 1979, but which failed to pass, would have eliminated the maximum payment clause, re- quired UDWR to pay for actual values lost, and given the total financial responsibility for depredation losses to UDWR once damage claims were filed. Before 1977 alfalfa depredation costs paid by UDWR were minor with most years after 1956 having less than 10 claims and total pay- ments less than $2,000. Since 1977 payments as well as fencing costs have risen dramatically with costs paid to farmers for summer field- growing alfalfa hay exceeding $29,000 in fiscal year 1984-85. In Utah wire baskets to determine depreda- tion loss of field-growing alfalfa hay have been utilized since 1953. To determine losses, paired plots (basketed and unprotected) were established as soon as possible following depredation complaints and hand clipped just prior to field cutting (Pederson 1982). Al- though the basket technique is widely used (Tebaldi and Anderson 1982), it has several difficulties. The time requirement to estab- lish, clip, and remove plots is very great, and the consistency of clipping and removing of materials is questionable. Furthermore, the number of plots used is usually few, and data on the number of plots required for a statisti- cally sound sample are largely unavailable. Nonetheless, Pederson (1982) recommended the use of one basket per 10 acres but added confidence intervals were wide. Palmer et al. (1982) used a density of one basket per 0.74 acres. An alternative method of determining depredation loss is the counting of depredat- ing animals and assuming a consumption rate. Although this method has been used success- fully, a major difficulty has been estimating the amount of hay consumed, particularly when rangeland forages are also consumed. In this report, data are presented for field alfalfa consumed under varying conditions by mule deer and elk. Methods Six tame adult mule deer, two bucks and four does, and four adult tame elk, one mature castrated bull and three cows, were fed alfalfa hay in summer to determine consumption. Deer and elk were kept separate, with each This report is acontribution of Utah Division of WikUife Resources, Federal Aid Project W-l()5-R Department of Range Science, Utah State University, Logan, Utah 84322. 100 January 1987 Austin, Uhness: Mule DeehandElk Diet 101 group collectively maintained in pens mea- suring about 25 X 40 m. In each trial animals were given access to fresh alfalfa hay for three consecutive nights. Hay, exceeding observed consumption, was cut and weighed each evening with orts weighed the following morning. Samples of both fresh hay and orts were collected daily for converting to dry weight consumption. A minimum of one day separated each trial. Three treatments were imposed and repli- cated three times in a random block design. In treatment 1 no other feeds were available to deer or elk. In treatment 2 lamb-grower pel- lets were offered to deer in excess of consump- tion while elk were given access to about 12 ha of dryland, grass pasture. In treatment 3, in addition to the feeds available in treatment 2, both deer and elk were given daily a variety of common browse and forb forages in excess of consumption. These forages included (juaking aspen {Popiihis tremuloides), common choke- cherry {Prunu.s viros ureophiluslAgropyron spicatum Artemisia tridentata-Symphoricarpos oreophilus/Agropyron trachycaiilum Artemisia tridentata-Symphoricarpos oreophihis/Festuca idahoensis Symphoricarpos oreophihisl Artemisia tridentatalArgropyron spicatum Symphoricarpos oreophihisl A rtcmisia t ride n ta talFestu ca ida h oe n sis 14 6 5 10 2 2378-3010 2592-2713 2531-2592 2287-3003 2470 cover, total cover, number of species, lati- tude, and longitude. TWINSPAN (two-way indicator species analysis) successively splits the ordination of all the samples into halves and identifies indicator species for each divi- sion. The divisions are arranged in the print- out in order showing the closeness of similar- ity between groups based on all species. The result is a classification of similar stands with the tightness of the groupings indexed by the eigenvalue of the division. The resulting clas- sifications for both association tables and mul- tivariate approaches were compared. We wanted to know if the multivariate approach, emphasizing all species equally, would de- scribe plant associations readily identifiable in the field and potentially useful to resource managers. Results Reconnaissance Reconnaissance data allowed us to identify 15 mountain brush communities based on dominant species in the shrub and herb layer: (1) Artemisia tridentata-Symphoricarpos oreophihisl Agropyron spicatum (2) Artemisia tridentata-Symphoricarpos oreophihisl C h rysoth amnu s v iscidiflo ru s (3) Artemisia tridentata-Symphoricarpos oreophihisl Chrysothamnus viscidifloriisl Agropyron spicatum (4) Artemisia tridentata-Symphoricarpos oreophihisl Festuca idahoensis (5) Artemisia tridentata-Symphoricarpos oreophihisl Poa sandbergii (6) Artemisia tridentata-Sym))horicar))os oreophihisl Stipa comata (7) Artemisia tridentata-Purshia tridentatal Agropy- ron spicatum (8) Artemisia tridentata-Purshia tridentatalFestuca idahoensis (9) Artemisia tridentata-Cercocarpos lechfoUusI Agro- pyron spicatum (10) Artemisia tridentata-Clirysothamnus viscidiflorusi Agropyron spicatum (11) Symphoricarpos oreophihis-Artemisia tridentatal Agropyron s})icatiim (12) Symphoricarpos oreophihis-Artemisia tridentatal Agropyron trachycauhim (13) Symphoricarpos oreophihis-Artemisia tridentatal Festuca idahoensis (14) Symphoricarpos oreophihis-Artemisia tridentatal Poa sandbergii (15) Symphoricarpos oreophihis-Artemisia tridentata- Amehinchier pallidal Agropyron spicatum Provisional association names were given to groups of stands with the same dominant spe- cies, the same combination of dominant spe- cies, or similar estimated cover percentages of certain species. Similarities among site factors such as elevation, aspect, percent slope, posi- tion on slope, and some soil characteristics (texture, structure, and percent sand and clay) were used as additional classification criteria. Some of these 15 communities were judged to be serai stages of major associations. Others were grouped into one of the five final desig- nations and considered to be incidental vari- ants. The remaining communities (8, 9, and 15) were excluded from the study because they did not fit the criteria selected for the detailed analysis. Intensive Study Knowledge gained during the reconnais- sance suggested that intensive work be con- fined to five (5) Artemisia tridentata vaseyana-Symphoricarpos oreophilus associ- 120 Great Basin Naturalist Vol. 47, No. 1 Table 2. Average density (No. associations. height (Ht.), and crown cover (Cv) for shrubs of the mountain brush plant Species Association Artr-Syor/Agsp Artr-StjorlAgtr Artr-SijorlFeid Syor-Artr/Agsp Syor-Artr/Feid Ht. Cv Ht. Cv Ht. Cv Ht. Cv Ht. Cv No.'' cm'' %'' No. cm % No. cm % No. cm % No." cm % Amelanchier pallida 2 17ir' — — — — — — e67r'— — — Artemisia tridentata (Artr) 59 67 23 73 75 26 61 69 .30 49 60 17 83 72 15 Berberis repens — — — e5T — — — — — — 1 3T Chrysothammis viscidijlorus 16 19 2 18 27 2 24 30 2 28 29 5 35 34 4 Gutierrczia sarothrae e 12 T — — — — — — — — — — — — Pontentilla glandulosa — — — e34 T — — — — — — — — — Prttnus virginiana e 25 T — — — — — — — — — — — — Purshia tridentata 2 63 T e 58 T — — ————— — — Ribes velutinum — — — — — — — — — 5 33 T — — — Rosa woodsii e 31 T — — — — — — e 31 T — — — Syinphoricarpos oreophilus (Syor) 322 43 17 118 36 14 311 .39 18 394 33 21 259 43 22 Tetradymia canescens e 28 T — — — — — — — 37 T — — — a - Number per 60 m" b - Average height (cm) values calculated for stands in which individuals occurred c - Average canopy cover percentage for a square meter d - Cover values less than 1% indicated as T e - Average density value less than 1 Agtr = Agropijron trachycauhim. Agsp Af:.ropyron spicatum ; Feid ^ Festuca idahoenaia Table 3. Constancy (Cn), frequency (Fr), and herb basal area (Cv) for species in the Artemisia tridentata vaseyanal Symphoricarpos oreophilus associations. Species^ Artemisia tridentata vaseijana- Symphoricarpos oreophilus- Af^ropyron trachycaulum Artemisia tridentata vaseyatia- Symphoricarpos oreophilus- Festuca idahoensis Artemisia tridentata vaseyana- Syniphoricarpos oreophilus- Ap'opyron spicatum Shrubs Cn Fr Cv Cn Fr Cv Cn Fr Cv Amelanchier pallida — — — — — — 60 1 — Artemisia tridentata 100 35 — 100 27 — 100 14 — Chrysothammis viscidijlorus 100 7 — 100 11 — 100 0 — Purshia tridentata — — — 40 1 — — — — Symphoricarpos oreophilus 100 10 — 100 5 — 100 8 — Herbs (Grasses) Agropyron spicatum 33 1 jh 100 6 0.2 100 6 1,5 Agropyron trachycaulum 100 4 2.1 40 3 0.5 — — — Bromus carinatus 17 1 O.I — — — — — — Bromus nmrginatus 17 1 T — — — — — — Bromus tectorum 67 2 T 80 5 0.3 87 4 0.1 Festuca idahoensis 83 6 1.0 100 5 2.7 47 3 0.3 Poa secunda 100 7 1.0 60 2 1.0 93 2 jh Sitanion hystrix 17 2 T — — — — — — (Forbs) Achillea millifolium — — — 40 5 T 80 2 T Agastache urticifolia — — — — — — 13 2 T Agoseris glauca 33 6 0.1 60 3 T 33 2 T Astragalus beckwithii 33 1 T — — — — — — Babamorhiza sagittata 50 4 T 40 2 T 80 5 T Collinsia parviflora 100 9 0.4 100 9 0.3 73 3 0.3 Comandra pallida — — — 40 2 T — — — Crepis acuminata 100 10 T 100 10 0.4 100 6 0.2 Eriogonum ovalifolium 50 2 0.3 — — — 27 1 T Lupinus caudatus 100 12 0.2 100 15 1.2 100 7 0.4 Mertensia oblongifolia 83 9 0.2 100 8 0.4 100 8 0.3 Myosotis scorpioides — — — — — — 20 2 T Penstenion hymilis 50 1 T 80 2 T 87 3 T Phlox longifolia 33 1 T 60 9 0.1 27 2 T Viola beckwithii 100 7 T — — — — — — a - Only species with frequencies of 1% or greater in the 3- \ 6-dm niicroplot are shown. b - Average basal area less than 0. 1% is indicated by T. January 1987 TUELLER, ECKERT: NEVADA PLANT ASSOCIATIONS 121 Table 4. Constancy (Cn), frecjuency (Fr), and herb basal area (Cv) for species in tbe Sijmphoricarpos oreophihis/ Artemisia tridentata vaseijana associations. Symphoricu \rpos oreophi lus- Symphoricarpos oreophilus- Artemisia tridentata vaseyana- Artemisia tridentata vase yana- Agropy, ron spicattim Festitca idahoensis Species^ Shrubs Cn Fr Cv Cn Fr Cv Amelanchier pallida 22 1 — — — — Artemisia tridentata 100 17 — 100 16 — Chrysothamnus viscidiflorus 100 21 — 100 12 — Ribes velutinum 56 5 — — — — Sijmphoricarpos oreophihis 100 8 — 100 9 — Herbs (Grasses) Agropijron spicatiim 100 9 2.1 — — — Agropijron trachijcauhim — — — 40 2 0.1 Bromus tectorum 89 4 0.1 100 8 0.2 Festiica idahoensis 78 6 T" 100 54 1.31 Melica bulbosa 11 1 T — — — Poa secunda 100 15 0.7 100 2 2.0 Stipa thtirberiana 11 4 T — — — (Forbs) Achillea millifolium 33 2 T — — — Agoseris glatica 78 19 0.3 — — — Aster scopulorum 67 4 T — — — Balsamorhiza sagittata 89 4 0.1 50 4 T Collinsia parviflora 100 11 1.1 100 4 0.3 Crepis acuminata 89 8 0.2 100 6 0.1 Delphinium andersoni 78 4 T — — — Eriogonum ovalifolium 11 3 T — — — Geranium viscossium 11 2 T — — — Hydrophyllum capitatum 67 3 T 50 10 0.2 Lomatiiim cons 44 1 T — — — Lapinus caudatiis 100 7 0.3 100 9 0.8 Mertensia oblongifolia 89 9 0.7 100 10 0.3 Penstemon humilis 89 4 0.1 — — — Phlox longifolia 78 4 T — — — Senecio canus 67 7 T — — — Viola beckwithii 22 2 T 100 4 0.1 a - Only species with frequencies ot 1% or greater in the 3- x 6-dm microplot are shown. b - Average basal area less than 0. 1% is indicated by T ations only (Table 1). These associations have the widest distributions and greatest abun- dance among the mountain brush plant associ- ations of northern and central Nevada. These associations are described below, followed by the description and interpretation of the mul- tivariate analysis. Data describing each plant association come from an association table which is on file at the University of Nevada, Reno. Vegetation characteristics for the five as- sociations are presented in Tables 2, 3, and 4. Artemisia tridentata vaseyana—Symphori- carpos oreophilus/Agropyron spicatwn Asso- ciation.— This association is widely dis- tributed throughout northern Nevada. Stands are located in mountainous terrain (2,378- 3,010 m) in concave snowpockets on 16 to 31% slopes with predominantly northern aspects. Species composition of this association is very similar among stands in Elko County. Stands from White Pine County show greater vari- ability. The diagnostic characteristic of this associa- tion is the dominance oi Artemisia tridentata in the shrub layer and of Agropyron spicatum in the herb layer. The average density of Artemisia tridentata (59 plants/60 m") is the lowest of the three associations with A. triden- tata the dominant shrub (Table 3). Artetnisia tridentata constitutes 55% of the total shrub crown cover, whereas Symphoricarpos oreophihis makes up 40% of the cover. Sijm- phoricarpos oreophihis always has a high den- sity but a low cover (Table 2). The average 122 Great Basin Naturalist Vol. 47, No. 1 Table 5. Soil surface characteristics for the associations dominated by Artejnisia tridentata vaseyana or Syinphori- carpos oreophilus . Soil surface characteristics Plant Litter Bare soil Gravel Stone Cryp- togam cover cover surface cover cover cover % % % % % % 36 27 24 9 29-41 15-40 16-34 0-18 Association Ai-tcnii.sia tridentata- Symphoricarpos oreophilus/ Agropyron spicatum Average 39 32 19 7 Range 21-49 20-47 5-30 1-13 Artemisia tridentata- Symphoricarpos oreophilus/ Agropyron tracliycaulum Average Range Artemisia tridentata- Symphoricarpos oreophilus/ Festuca idahoensis Average 42 39 Range 34-48 21-46 Symphoricarpos oreophilus Artejnisia tridentata/ Agropyron spicatum Average 42 31 Range 37-47 17-48 Symphoricarpos oreophilus Artemisia tridentata/ Festuca idahoensis Average 41 36 Range 37-45 21-50 15 4-34 15 8-26 14 3-26 2 0-9 7 1-12 6 1-12 0-5 2 0-7 Trace 0-2 Trace 0-2 2 0-4 Trace 0-2 2 0-6 2 0-2 Trace 0-2 1 0-2 height of A. tridentata varies from 55 to 75 cm. Chrysothamnus viscidiflonis is 100% constant but contributes httle to total plant cover. Eight other shrub species are found in these stands. Four grass species and 12 forb species are found in this plant association (Table 3). Basal area and frequency o( Agropyron spicatum is much greater than for any other herb in all stands. This species constitutes 79% of the total grass basal area and 48% of the total basal area of the herb vegetation. Festuca idahoen- sis and Lupinus caudatus are subdominant species in the herb layer. Total basal area of forbs is the lowest among all associations and is the most variable vegetation characteristic among stands in this association. Forbs with high constancy are Archillea millifoliian, Bal- samorhiza sagittata, Collinsia parviflora. Crepis acuminata. Delphinium andersonii, Lupinus caudatus, Mertensia oblongifolia, and Penstemon humilis. Viola bcckwithii is highly constant among the stands in White Fine County but absent in the Elko County stands. Lithospermum ruderale is a character- istic species of stands in the northern Ruby Mountains and Jarbidge areas but is absent in White Pine County. Basal plant cover and litter cover are com- paratively high, 39% and 32% respectively (Table 5). The bulk of the litter occurs under- neath and around the periphery of shrub crowns and consists primarily of leaf material from the shrubs, particularly A. tridentata and S. oreophilus. Few plants occur under- neath the crown of A. tridentata, but nearly always plants of several species grow under- neath the canopy of S. oreophilus. January 1987 TUELLER, ECKERT: NEVADA PlANT ASSOCIATIONS 123 Table 6. List of soil fomilics supporting Artemisia tridcntata vasi'tiaiia and Syinphoricarpos oreophihts plant associations. Artr-Svlo/ Artr-Svlo/ Artr-Svlo/ Svlo-Artr/ Svlo-Artr/ Soil family Agsp Agtr Feid Agsp Feid % % % % % Argic Cryohoroll, claye\ o\ er sand\ or sandy-skeletal, niontmorillonitic Argic Cryoboroll, fine-loamy, mixed Argic Pachic Cryoboroll, clayey over sand or sandy-skeletal, niontmorillonitic Argic Pachic Cryoboroll, fine-loamy, mixed Argic Pachic Cryoboroll, fine-loamy over sandy or sandy-skeletal, mixed Argic Pachic Cryoboroll, fine, niontmorillonitic Mollic Cryoboralf clayey over sandy or sandy- skeletal, niontmorillonitic Mollic Cryoboralf fine-loamy, mixed Mollic Cryoboralf fine, niontmorillonitic Mollic Cryoboralf fine-loamy over sandy or sandy-skeletal, mixed Ochreptic Cryoboralf, loamy, mixed Typic Cryoboralf fine-loamy, mixed Typic Cryoboralf fine-loamy over sandy or sandy or sandy-skeletal, mixed 13 20 13 13 16 17 17 33 17 20 20 20 20 22 45 11 50 50 Agsp - Agropyron spicatum Agtr ^ Af^ropyron trachycaulum Artr - Artemisia tridentata Feid = Festuca idahoensis Sylo = Sytnphoricarpos oreophihts Soils are largely cryoborolls or cryoboralfs; 27% are Agrie Cryoborolls, while 53% are one of four families of Mollic Cryoboralfs (Table 6). Many of the soils have dark brown to dark reddish brown, sandy loam and clay loam, angular and subangular blocky argillic hori- zons. Average solum gravel content varies from 10 to 30%. Thickness of the solum ranges from 42 to 98 cm. Most of the soils have fine- loamy textures (Table 7). Surface soils gener- ally have low gravel and stone cover and small amount of bare soil (19%) due to high plant and litter cover. Artemisia tridentata vaseijana-Symphor- icarpos oreophilus/ Agropyron trachycaulum Association. — Stands representing this asso- ciation are located in the Schell Creek Range, Ward Mountain, and Mt. Moriah areas of White Pine County with one stand in Elko County. All are located in mountainous ter- rain on concave to gently convex slopes with northeastern and northwestern aspects. Slopes range from 12 to 38%, and elevations range from 2,592 to 2,713 m. The dominance oi Artemisia tridentata in the shrub layer and Agropyron trachycaulum in the herb layer characterize this association (Table 3). The average density of A. tridentata (73 plants/60 m") is next to the highest of all associations studied (Table 3). Average cover of A. tridentata (26%) is 62% of the total shrub crown cover. Syinphoricarpos oreophilus cover (14%) constitutes 33% of cover. The average density of S. oreophilus (181 plants/60 m") is the lowest among the associations stud- ied (Table 3). Shrubs of secondary importance are Chrysothamnus viscidiflorus and Purshia tridentata. Fourteen grass species constitute 78% of a total grass basal area of 4.2%. Basal area of Agropyron trachycaulum (2.1%) constitutes 50% of the total grass basal area and 39% of the basal area of all vegetation (5.4%). Festuca idahoensis and Poa sandbergii are subdomi- nant species. The forb component (22 species) is very similar in composition to that of the Artemisia tridentata vaseyana-Symphori- carpos longiflorusi Festuca idahoensis associ- ation. Characteristic species with 50% con- stancy are Collinsia parviflora, Crepis acuminata, Lupinus caudatus, Balsamorhiza sagittata, Eriogonum ovalifolium, Mertensia oblongifolia, and Penstemon humillis (Table 3). Combined plant and litter cover accounts for 63% of the soil surface cover. The amount 124 Great Basin Naturalist Vol. 47, No. 1 Table 7. Summary of textural classes' and diagnostic horizons of'soils supportine; stands oH Artemisia tridentata and Symphoricarpos oreophilus . Associations and number of stands sampled Diagnostic horizons Soil famiK' texture class in control section Epipedons Subsurface horizons Coarse- F"ine- Fine Very Loamy- Clayey- MoUic Ochric Argillic Cambic loamv loamv fine skeletal skeletal %" Artr-Sylo/ Agsp (14) Artr-Svlo/ Agtr (6) Artr-Svlo/ Feid (5) Svlo-Artr/ Agsp (10) Sylo-Artr/ Feid (2) 47 13 67 16 22 60 33 100 20 45 — — 33 40 60 93 17 67 33 83 20 40 60 100 100 50 17 78 22 78 22 50 a - Soil family textural classitication in si)il taxouonn (Soil Survey Staff 1975) b - Percent of stands Artr Artemisia tridentata Sylo Symphoricarjios longiflorus Agsp - Agropyron spicatum Agtr Aoropijron trachycatiliim Feid - Festuca idahoensis of bare soil (24%) is the highest of all associa- tions, and gravel cover and stone cover are 9% and 2%, respectively (Table 5). Soils are both cryoboralfs and cryoborolls (Table 6). The cryoborolls are all Argic Pachic Cryoborolls with fine-loamy to sandy-skeletal textures (Table 7). The epidedons are pre- dominantly mollic, and most soils (83%) have argillic subsurface horizons. Average gravel content varies from 5 to 25%. Only one profile was found on bedrock (74 cm deep). Artemisia tridentata vaseyana— Symphori- carpos oreophilus/ Festiica idahoensis Associ- ation.— Two of the stands representing this association are located on Spruce Mountain, two on Mt. Moriah, and one in Harrison Pass. Each stand occurs in mountainous terrain on 19 to 29% slopes with north, east, and west aspects and elevations of 2,531 to 2,592 m. The vegetation is characterized by the dom- inance of A. tridentata in the shrub layer (Table 2) and Festuca idahoensis in the herb layer (Table 3). Arteitiisia tridentata cover of 30% constitutes 60% of the total shrub crown cover and has a density of 61 plants/60 m". Symphoricarpos oreophilus cover of 18% con- stitutes 36% of the total shrub crown cover and has a very high density (311 plants/60 m") (Table 3). Chrysothamnus viscidiflorus is one of four highly constant shrubs but contributes little to total crown cover. The total grass basal area (4.7%) is com- posed almost entirely of Festuca idahoensis (2.7%) and Poa sandbergii (1.0%); Agropyron traclnjcaulum is a minor species. Only six grass species were found. Festuca idahoensis comprises 38% of the total herbaceous basal area and 58% of the total grass basal area. The total herbaceous basal area (7.1%) and the total grass basal area (4.7%) are the highest of the associations studied. The total forb basal area (2.4%) is the highest among A. triden- tata-domiivdted stands. The forb component consists of 20 species. Species with 80% con- stancy or greater are Collinsia parvijlora, Crepis acuminata, Lupinus caudatus, Mertensia oblongifolia, Penstemon humilis, and Viola beckwithii. The first four species are the most abundant. Average plant basal area cover (42%) and Htter cover (39%) are the highest of all associations studied (Table 5). Gravel, stone, and cryptogam cover is very low. The bare soil surface (15%) is intermediate for all associations studied but is the lowest with respect to other A. triden- tofa-dominated plant communities. January 1987 TUELLER, ECKERT: NEVADA PLANT ASSOCIATIONS 125 At least 60% of the soils are Mollie Cryobo- ralfs with a few Argic Pachic Cryoborolls (Ta- bles 6, 7). All subsurface horizons are argillic, and ochric epipedons are common. The most common soil family textural class is fine-loamv (Table 7). ' Symphoricarpos oreophihis— Artemisia tri- dentata vaseijanal Agropijron spicatum Asso- ciation.— This association occurs in the south- ern Schell Creek Range with three exceptions. Two stands are in the Jack Creek area of Elko County and one stand is on Spruce Mountain. Stands are found on 10 to 30% slopes with northerly aspects at eleva- tions between 2,287 and 3,003 m. Robust Symphoricarpos oreophihis shrubs and an herb layer dominated by Agropyron spicatum characterize the vegetation (Tables 2, 4). In addition, this association has less A. tridentata (17%) than did the first three asso- ciations described. Symphoricarpos ore- ophihis cover (21%) comprises 49% of the total shrub cover and has the highest shrub density (394 plants/60 m") of all associations studied. Artemisia tridentata constitutes 38% of the shrub crown cover but has a very low density (49 plants/60 m"). Besides S. oreophihis and A. tridentata, Chrysothamnus viscidifloriis is the only other important shrub, although Ribes vehitintim has a constancy of 5% (Table 4). Agropyron spicatum and Poa secunda have 100% constancy in this association. Fourteen grass species were found. Agropyron spica- tum cover (2.1%) comprises 41% of the total herbaceous basal area (5.9%) and 68% of the total grass basal area (3.1%). Lupinus cauda- tus and CoUinsia parviflora have constancies of 100% and contribute 50% of the total forb basal cover (28%) for 32 forb species. Merten- sia oblongifoUa and Agoseris glauca have con- stancies of 89% and 78%, respectively, and contribute 40% of the average total forb basal area (Table 4). Festuca idahoensis and Senecio canus have low constancies but comprise a significant portion of the total forb basal area in some stands. Other forbs characteristic of this association are Penstemon humiUs, Crepis acuminata, and Balsamorhiza sagittata. Plant and litter cover combined (73%) is the lowest of the S. oreophihis plant associations and is related to the high bare soil surface percentage of 19% (Table 5). Gravel cover (7%) was next to the highest among all the associations, but stone and cryptogam cover was the lowest of all associations. Nearly half of the soils are fine, montmoril- lonitic Argic Pachic Cryoborolls (Table 6). An- other 22% are a fine-loamy, mixed family of the same soil subgroup. Symphoricarpos oreophihis-Artemisia tri- dentata vaseyana/Festuca idahoensis Associ- ation.— Two stands represent this associa- tion, one on Mt. Moriah and the other on Ward Mountain in White Pine County. These stands occur on 26 and 28% slopes, respec- tively, and with northeast and northwest as- pects at about 2,470 m. The vegetation is characterized by the dom- inance of Symphoricarpos oreophihis in the shrub layer and Poa sandbergii and Festuca idahoensis in the herb layer (Tables 2, 4). The physiognomy of this association is quite distinct from other plant associations because of the lack of a noticeable sagebrush aspect. These sites are snowpockets and are obviously dominated by S. oreophihis, a dark green shrub generally lacking the dull gray appear- ance of A. tridentata. Symphoricarpos ore- ophilus has a high density and a cover (22%) that comprises 53% of the total shrub crown cover (Table 2). The average total basal area of herbaceous vegetation (5. 1%) and the average total grass basal area (3.3%) are comparatively low when compared with the other associations in this study. Poa sandbergii has 2% cover and Fes- tuca idahoensis has 1% cover (Table 4). Nei- ther grass is clearly dominant. The association was named after Festuca idahoensis because it is considered to be the dominant perennial grass on these sites. Poa sandbergii composes 61% of the total grass basal area and 40% of the total basal area of herbaceous vegetation. All other grass species have low basal area and frequency, except Festuca idahoensis. Forbs are sparse; only 23 species were found, and frequency percentages are low. The floristic structure of forbs resembles the Artetnisia tri- dentata vaseyana-Symphoricarpos oreophi- hislFestuca idahoensis association, which had both low forb constancy and frequency. Highly constant forbs are CoUinsia parvi- flora, Crepis acuminata, Mertensia oblongi- foha, Lupinus caudatus, and Viola beck- withii. Bare soil surface is the lowest of the associa- tions studied and results from a high plant and 126 Great Basin Naturalist Vol. 47, No. 1 Table 8. Number of stands sampled falling into either TWINSPAN groups or plant associations based on dominant species. Plant TWINSPAN group associations c E B D A Totals Artr/Syor/Agsp Syor/Artr/Agsp Artr/Syor/Agsp Syor/Artr/Feid Artr/Syor/Feid Totals 4 4 7 2 9 3 1 3 1 2 10 3 1 1 5 7 2 9 14 10 6 2 5 37 Artr = Artentisia tridentata Agtr - Agropyron thchophorum Feid = Festuca idahoensis Syor Agsp Symphoricarpos ore Afirupyron spicatum ophilus litter cover. Gravel, stone, and cryptogam cover is very low. One soil is a fine-loamy to sandy-skeletal Typic Chryochrept and the other a mollic Cryoboralf (Table 7). Both soils are neutral in reaction with roots well dis- tributed throughout the profile. Multivariate Analysis The TWINSPAN classification clearly did not separate the plant associations in the same way as did the associations table groupings which were based on the dominant shrub and the dominant perennial grass (Fig. 4, Table 8). The TWINSPAN dendrogram organized the study site into five groupings based on the similarity of occurrences of specific indicator species. These floristically based groups had specific geographic locations (Fig. 1). Their distribution, with only a few exceptions, is characterized by a north-south orientation and by association with specific mountain ranges. These results are an expression of the north-south environmental control of the in- dicator species delineated by the TWINSPAN analysis. Environmental controls are such that many groupings are found only on certain mountain ranges or only in the north or south part of the study area. The TWINSPAN groups were associated with one, two, or three plant associations with the exception of Group B which has representatives from each association (Table 8). Group A is separated with the following indicator species: Astragalus kentroplujta iin- plexus, Hydrophyllum capitatum, Senecio canus. Astragalus sp., and Rihes velutinum. Elymus cinereus and Phlox longifoUa are also indicators but less definitive than those listed above. Lithospermu7n ruderale is conspicu- ous bv its absence. These stands are found primarily at the southern end of the site distri- bution and have Agropyron spicatum as the dominant perennial grass. Aspects are north- west and are found at relatively high eleva- tions, mostly above 2,800 m. These stands tend to be much drier than expected for their elevation with relativelv low vegetation cover (43%). Group B indicator species include Agropy- ron trachycaulum and Sitanion hystrix, al- though the latter species is not a strong prefer- ential. Phlox longifolia tends to be absent as does Delphinium andersonii. These sites are found at intermediate elevations (mostly be- low 2,600 m) on northeast aspects and are probably drier than Group A. However, these stands had the highest total vegetation cover of all stands studied (65%). Group G has the following species as indica- tors: Eriogonum ovalifolium, Stipa comata, Collinsia parviflora, und Allium acuminatum. Agoseris glauca and Phlox longifolia are no- ticeably absent. These stands are found in the south Ruby Mountains at elevations near 2,400 m. However, they are relatively moist sites, wetter than would be expected for the elevation. Group D has Astragalus calycosus, Berheris repens, and Myosotis scorpiodes as indicator species. Balsamorhiza sagittata and Agoseris glauca tend to be absent from these stands. They tend to be average in terms of elevation (2,600 m) and moisture. Group E indicators are Calychortus ele- gans, Rosa woodsii, and Tetradtjmia canes- cens. Festuca idahoensis is generally missing in these stands. Elymus cinereus is also impor- tant in this group of stands. They occur at relatively low elevations (< 2,500 m) in the northern part of the distribution (Fig. 1). January 1987 TUELLER, ECKERT: NEVADA PLANT ASSOCIATIONS 127 Idaho tWiiincimuca 18 .19 J 6 Elko Lander GROUP A-O GROUP B-D GROUP C-O GROUP D-A GROUP E-0 • Klk( 0 ^13 0^15 25on 23 D 10^^11 A 32 33 26 on^^ Eureka D' White PineA 35 A 3inrn28 n Nye Fig. 1. Location of detailed study sites in Elko and White Pine counties of northeastern Nevada. The group designations indicate the location of the five TWINSPAN groupings. ther elucidate the environmental factors asso- ciated with distribution of these stands of veg- etation. Axis 1 (Figs. 2, 3) is significandy cor- related with decreasing latitude. A north-south distribution of the stands goes from approximately 41 degrees to 39 degrees North latitude. This axis is also significantly correlated with a significant reduction in the number of species/stand from 22 to 18. Axis 2 (Fig. 2) represents a gradient signifi- cantly correlated with increasing elevation, higher solar radiation intensities, and a some- what reduced number of species. Elevation along the gradient increases from 2,600 to 2,800 m. The radiation index increases from 42 to 45 with a very slight but significant re- duction in the number of species. The distribution of the A.xis 3 standard devi- 128 Great Basin Naturalist Vol. 47, No. 1 w 5 X o < » 200 180 160 140 120 100 - S 80 - 60 - 40 20 - 9f^ Artemisia Iridentata/Symphoricarpos oreophiluslAgropyron spicatum • Artemisia tridentatalSymphoricarpos oreophiluslAgropyron trachycaulum O Artemisia tridentatalSymphoricarpos oreophiluslFestuca idahoensis ■ Symphoricarpos oreophilusi Artemisia tridentatal Agropyron spicatum D Symphoricarpos oreophilusi Artemisia tndentatalFestuca idahoensis TWINSPAN Groups A thru E 0 NORTH 20 40 60 80 100 120 Decreasing number of species AXIS-1 140 Fig. 2. DECORANA ordinations of Axis 1 and Axis 2 with separation of the five plant associations interpreted from the association table. Lines circle the TWINSPAN groups. ations showed significant correlations with de- creasing grass cover, shrub cover, and total vegetation cover along with an increase in the number of species per stand from 17.6 to 21.5. Grass cover decreased from 5.9 to 0.9%, shrub cover from 57.2 to 36.1%, and total vegetation cover from 65.7 to 37.6%. Ordination of the 37 stands in this study showed significant relationships to environ- mental factors. The first axis (Axis 1) is related to latitude and species number in the stand and Axis 2 to elevation increases and the asso- ciated higher solar radiation intensities. Axis 3 is representative of a reduced level of shrub, grass, and total vegetation cover. Further comparisons between the plant as- sociations and the TWINSPAN groups show that the Artemisia tridentatalSymphoricar- pos oreophiluslAgropyron trichophoriim sites are found at southern locations within the study area and Artemisia tridentatal Sy7n- phoricarpos oreophilusi Agropyron spicatum stands are found further north. The other three plant associations are found at interme- diate latitudes. Total vegetation cover was highest for Artemisia tridentatalSymphori- carpos oreophiluslFestuca idahoensis stands. Soils Soils associated with these mountain brush associations are primarily mollisols or alfisols, although two are inceptisols. Well over half have argillic horizons that are not restrictive to rooting. pH values are generally near neu- tral or slightly acidic. Epipedons are either ochric or mollic with a few more of the latter. January 1987 TUELLER, ECKERT: NEVADA PLANT ASSOCIATIONS 129 200 s.d. 180 160 - 140 ^ Artem/sia tridentatalSymphoricarpos oreophilusiAgmpyron spicalum 0 Artemisia tridentatalSymphoricarpos oreoptiiluslAgropyron tractiycaulum O Artemisia tridentatalSymphoricarpos oreophiluslFestuca idahoensis ■ Symphoricarpos oreophilusi Artemisia tridentatalAgropyron spicatum D Symphoricarpos oreophilusi Artemisia tridentatai Festuca idahoensis TWINSPAN Groups A thru E NORTH 86^ 100 120 140 Decreasing number of species m AXIS-1 220 s.d. SOUTH Fig. 3. DECORANA ordinations showing A.xis 1 and Axis 3 with separation of the five plant associations interpreted fi-om the association table. Lines circle the TWINSPAN groups. The soil family textural classes are mostly fine- loamy, indicating good plant growth and root- ing characteristics. Those soils that are clayey are also skeletal and indicate a good rooting medium (Table 7). Soils supporting Festuca idahoensis have a deeper solum (A + B horizon) that averages 79 cm, while those soils supporting stands of ei- ther Agropyron spicatum or Agropyron tra- chaycaulum have a solum depth averaging only 68 cm. The Festuca idahoensis sites also have a higher litter cover, lower bare soil surface, and lower gravel and stone cover than do surface soils on the more xeric Agropyron spicatum and Agropyron trachycauhim asso- ciations. These soils are generally well drained, loamy, deep, sometimes rocky, and dark colored with manv roots, no restrictive layers, and relatively high organic matter. Discussion Mountain brush rangeland associations dominated by either Artemisia tridentata vaseyana or Symphoricarpos oreophihis have not been studied extensively. The works of Blackburn et al. (1968a, b, c, 1971a) list only a few such associations. Most studies of the ecology of A. tridentata vegetation have gen- erally ignored these low-acreage, high-pro- ducing plant associations. Blackburn et al. (1969a) described an Artemisia tridentatalSymphoricarpos vac- cinoides association in western Nevada with 30% cover of A. tridentata and only 3% cover for S. vaccinoides. Blackburn et al. (1968a, 130 EIGENVALUE .385 .348 .311 .274 .237 .200 .163 .126 .089 Great Basin Naturalist Vol. 47, No. 1 n I 3 25 26 1 2 4 5 6 7 1120 21 23 24 27 28 29 30 31 33118 9 10 11||32 34 35 36 371116 17 22 19 12 14 15 18 13 | GROUP A GROUP B GROUP C GROUP D GROUP E Fig. 4. TWINSPAN dendrology showing the separation of five groupings of the 37 study plots. 1971) described a low sagebrush association, Artemisia longiloba/Poa sandbergii, and an Artemisia tridentatal Agropijron smithii/Poa nevadensis association, both of which contain some S. oreophihis. Additionally, they de- scribed an Artemisia t ridentatal Symphoricar- pos oreophilusl Agropijron spicatum associa- tion with 16.3% cover for Artemisia and 15.6% cover for Sipnphoricarpos . The same association has 2.0% cover (or Agropijron spi- catum and 1.0% cover for Festuca idahoensis. Several low serai communities were de- scribed that have some Symphoricarpos. They were Artemisia tridentata/Chrysotham- nus viscidiflorus/Poa sandhergii/Wyethis mol- lis, Artemisia tridentata/Chrysothamnus vis- cidiflorus/Sitanion hystrix, and Artemisia tridentatal Poa sandhergiilBalsamorhiza sag- ittata. Also they described an Artemisia tri- dentata (10.2% cover)/Symphoricarpos ore- ophihis {4.5%)/Amelanchier paUida (4.5%) association. Mooney (1985) recently de- scribed seven Artemisia tridentata vaseyana plant associations in the Great Basin. Many of these stands contain Symphoricarpos ore- ophihis. Little biomass productivity data for these sites are available. However, their relatively greater number of species, deeper soils, and higher total ground cover lead to the conclu- sion that production is high for these commu- nities relative to most other sagebrush-domi- nated plant associations. Both Daubenmire (1970) and Franklin and Dyrness (1969) de- scribed the Festuca idahoensisi Symphoricarpos alhus habitat type. Daubenmire found that the total production of all vasculars was 30gm " while total grass production was 105m"". The groupings differentiated with the TWINSPAN dendrogram, apart from Groups A and C, do not show a strong relationship with the subjectively determined associations based on dominant species. Group A includes primarily Symphoricarpos oreophilusl Arte- misia tridentatal Agropyron spicatum plant associations. Group C is made up of the Artemisia tridentatal Symphoricarpos ore- ophilusl Agropyron spicatum plant associa- tion. The other groupings all show greater variability. This suggests that objective classi- fication approaches based on presence and absence of all species may give classifications that differ substantially from those based on the presence of designated dominant species which were done here in the association table analysis. The Artemisia-Syrnphoricarpos associa- tions may represent a moisture gradient as one goes from high Artemisia to low Symphor- icarpos and the reverse. They do represent relatively low-acreage, high-producing sites within the Artemisia vegetation. January 1987 TUELLER, ECKERT: NEVADA PlANT ASSOCIATIONS 131 Acknowledgments The authors are indebted to Kenneth R. Riemer for assistance in gathering data; to Harry Summerfield and F. F. Peterson for assistance in classification of soils; to Hugh Mozingo for identification oi certain taxa; and to Ed Kleiner, Stan Smith, and Robin Tausch for review of the manuscript. Literature Cited Blackburn. W H 1967. Plant succession on selected habitat types in Nevada. Unpublished thesis. Uni- versity of Nevada, Reno. 162 pp. Blackburn. W. H., P T. Tueller. and R E Eckert. Jr 1968a. Vegetation and soils of the Crowley Creek Watershed. Univ. Nevada E.xpt. Sta. Bull. R 42. 60 pp. 1968b. \'egetation and soils of the Duckwater Water- shed. Univ^ Nevada E.xpt. Sta. Bull. R40. 80 pp. 1968c. Vegetation and soils of the Mill Creek Water- shed. Univ. Nevada Expt. Sta. Bull. R43. 72 pp. 1969a. Vegetation and soils of the Churchill Canyon Watershed. Univ. Nevada Expt. Sta. Bull'. R 45. 157 pp. 1969b. Vegetation and soils of the Pine and Mathew Canyon Watersheds. Univ. Nevada Expt. Sta. Bull. R46. Hipp. 1969c. Vegetation and soils of the Cow Creek Watershed. Univ. Nevada Expt. Sta. Bull. R 49. 80 pp. 1969d. Vegetation and soils of the Coils Creek Watershed. Univ. Nevada E.xpt. Sta. Bull. R 48. 81pp. 1971. Vegetation and soils of the Rock Springs Watershed. Univ. Nevada E.xpt. Sta. Bull. R 83. 116 pp. Daubenmire. R F 1952. Forest vegetation of northern Idaho and adjacent Washington and its bearings on concepts of vegetation classification. Ecol. Monogr. 22: 301-330. 1970. Steppe vegetation of Washington. Washing- ton Agric. Expt. Sta. Tech. Bull. 62. 131 pp. Fr.\nk, C , and R Lee. 1966. Potential solar beam irra- diation on slopes. Tables for 30° to 50° latitude. L'.S. Forest Service Research Paper RM-18. 116 pp. Hanson. H. C, and E. D Churchill 1961. The plant community. Reinhold Publishing Corp., New York. 218 pp. Hill, M. O 1979. DECORANA, a FORTRAN program for arranging multivariate data in an ordered two- way table by classification of the individuals and attributes. Ecology and Systematics, Cornell Uni- versity, Ithaca, New York. Hunt, C B 1967. Physiography of the United States. W. H. Freeman and Co., San Francisco. 480 pp. McArthur. E 1979. Sagebrush systematics and evalua- tion. Pages 14-22 in Proceedings Sagebrush Ecosystem Svmposium, Utah, April 1978. MOONEY, J 1985. A preliminar>- classification of high-ele- vation sagebrush-grass vegetation in northern and central Nevada. Lhipublished thesis. University of Nevada. 118 pp. Passey, H B . AND V. T HuGiE 1962. Sagebrush on relict ranges in the Snake River plains and northern Great Basin. J. Range Manage. 15: 273-278. POULTON, C E , AND E. W. TiSDALE 1961. A quantitative method for the description and classification of range vegetation. J. Range Manage. 14: 13-21. WiNWARD, A H . AND E W TiSDALE 1969. A simplified chemical method for sagebrush identification. Forest, Wildlife, and Range Expt. Sta. Note No. 11, March 1969. Zamora. B., and P T. Tueller. 1973. At-tcmisia arbus- ctila, A. longiloba, and A. nova habitat types in northern Nevada. Great Basin Nat. 33(4): 255-264. HABITAT AND COMMUNITY RELATIONSHIPS OF CLIFFROSE {COWANIA MEXICAN A VAR. STANSBC/R/ANA) IN CENTRAL UTAH K. P. Price' and J. D. Brotherson" Abstract — Cliffrose {Coivania mexicana var. stansbtihana [Torr.] Jepson) community measurements were taken in central Utah. Data revealed a high between-site similarity of 78.5%. Soil analysis for sites showed most macronutrients, and some micronutrients, relatively low. Cover of cliffrose was found to increase with increases in soil magnesium (p < 0.01). Plants growing on the sites have adapted life cycles to exploit moisture and nutrients during seasons of ma.\imum availability. Prevalent species in the community were cheatgrass (Bromus tcctorum), cliffrose, madwort {Ahjssum alyssoides), and bluebunch wheatgrass (Agropyron spicatum). Annual grasses were the most important life form to community composition; the second was shrubs. Ratios between soil nutrients and cliffrose tissue nutrients indicate active transport of some elements. Data indicated a steady decline in establishment of new cliffrose individuals on the sites since 1957. This lack of reproductive success is most likely due to a combination of factors but appears most influenced by the elevated levels of annual plants (mainly cheatgrass) on the sites. If the cliffrose communities in central Utah are to be maintained, special attention to their management must be considered and implemented. Cliffrose (Cowania mexicana var. stans- buriana [Torr.] Jepson) (McMinn 1939) is an evergreen shrub, a member of the rose fam- ily, and is found growing on dry, rocky slopes in the western United States (McArthur et al. 1983). The plant ranges from 1 to 4 m in height, but under favorable circumstances near the south rim of the Grand Canyon it becomes a small tree 6 to 8 m high (Dayton 1931, Blaueretal. 1975). In central Utah it is characteristically found associated with limestone areas on west and southwest slopes at elevations between 1,200 and 2,400 m. Elsewhere, it is found on granitic, volcanic, and other igneous forma- tions where it is most often associated with juniper, pinyon, mountain mahogany, ser- viceberry, sagebrush, live oak, and other moderately dry site (xerophytic) shrubs and small trees (U.S. Forest Service 1937). The geographical range of cliffrose reaches from western Colorado to California and from northern Utah to Mexico (McMinn 1939, McArthur et al. 1983). Although its herbage has a bitter taste, cliff- rose is a valuable browse species for many animals. On the Kaibab Plateau of northern Arizona, degree of twig use on cilffrose was, for many years, viewed as an indicator of hunt- ing pressure needed to control the deer herds (McCulloch 1966). Since cliffrose is found mostly on low-elevation deer winter ranges, is evergreen, and stands above the snow and within reach to permit grazing, it is one of a few available food sources for deer during the critical winter period. The importance of cliffrose as forage for both livestock and wildlife has stimulated studies dealing with its potential in range revegetation and in reclamation (McCulloch 1969 and 1971, Alexander et al. 1974, Plum- mer 1974, Giunta et al. 1975, Evans and Young 1977). Other studies have dealt with its utilization by deer and livestock and its re- sponse to browsing (Jensen and Scotter 1977, McCulloch 1978, Neff 1978, Jensen and Urness 1981). Smith (1957) compared the nutritional value of cliffrose with other important range shrubs. His data show cliffrose to be average when compared with other shrubs. Welch et al. (1983) found cliffrose to have winter crude protein levels of 8.8% and winter in vitro di- gested dry matter contents of 36.7%. Both of these values rank well among comparable val- ues for other winter forages. Other works on cliffrose include seed ger- mination (Piatt and Springfield 1973, Stevens et al. 1981, Young and Evans 1981), hy- bridization and introgression of cliffrose into bitterbrush (Stutz and Thomas 1963, Blauer et al. 1975, Koehler and Smith 1981, 'Department of Geography. University of Utah, Salt Lake City. Utah 84102. Botany and Range Science. Brigham Young Universit\ , 4.3.5 WIDE, Provo, Utah 84602. 132 January 1987 Price, Bhotherson: UtahCliffrose 133 UTAH COUNTY UTAH ▲ STUDY SITES ij CITIES & TOWNS _ HIGHWAYS __ TRIBUTARIES Fig. 1. A map of the study area (Utali County) in eentral Utah. The site names are: (1) Edgeniont-Provo Canyon Junction; (2) American Fork Canyon; (3) Springville; (4) Santacjuin; (5) Rock Canyon; (6) Provo River bottom; (7) Northern Provo Canyon; (8) Spring Lake; (9) Southern Indian Hills; and (10) Northern Indian Hills. McArthur et al. 1983), secondary chemistry (Haynes and Holdsworth 1980) nitrogen-fix- ing ability (Righetti and Munns 1980, Nelson 1983, Righetti et al. 1968), and root morphol- ogy (Chne 1960). A literature search revealed few studies ad- dressing the ecology and habitat require- ments of cliffrose. However, some studies were foimd dealing with the subject. Fairchild and Brotherson (1980) discussed the microhabitat relationships of six major shrubs in Arizona (which included cHffrose); Mor- tensen (1970) studied the ecological variations of leaf anatomy of apache plume {FaUxigia paradodoxa), cliflFrose, bitterbrush {Purshia sp.), and mountain mahogany (Cercocarns sp.); Stutz and Thomas (1964) and McArthur et al. (1983) studied habitat differences be- tween antelope bitterbrush and Stansbury cliflfrose; and Koehler and Smith (1981) de- scribed sites where desert bitterbrush and Stansbury cliffrose grow together with desert bitterbrush occupying slightly lower elevations. Since cliffrose assumes a vital role in sus- taining wildlife, and since there is a lack of studies dealing with its habitat relationships, this study of cliffrose was undertaken to fur- ther our understanding of its habitat require- ments. Our objectives were to investigate the habitat and community relationships of cliff- rose in central Utah where it is growing near the limit of its northern range (Cole 1982, McArthur et al. 1983) and to determine fac- tors affecting its growth and establishment. This information .should aid in the formulation of management plans to improve wildlife win- ter range. Study Area The study area, confined to central Utah (Fig. 1), is located along the west face of the 134 Great Basin Naturalist Vol. 47, No. 1 Table 1. IliKlis, lows, nifans, standard deviations, and foeflicients ol variation lor abiotic factors as.sodated with the chffrose sites in central I' tali. Standard Coefficient Aliiotic factors High Low Mean deviation of variation General site factors 10.3 % Gravel 62.0 30.0 48.7 21.1 % Sand 76.0 3.0 53.6 23.9 25.9 % Silt 41.0 15.0 27.9 8.5 30.5 % Clay 34.0 10.0 18.3 7.5 41.0 % Organic matter 7.1 2.5 4.8 1.6 33.3 Soil penetrability (cm) 28.0 9.0 17.9 7.4 41.3 Soluble salts 477.0 330.0 .398.4 48.1 12.1 Aspect (degrees) 330.0 140.0 244.0 58.5 24.0 % Slope 73.0 2.0 42.8 26.2 61.2 Elevation (m) 1591.0 1472.0 1.562.0 .38.9 2.5 pH 7.7 7.6 Soil nutrients 7.7 0.04 0.053 0.5 Nitrogen {%) 0.2.30 0.054 0.129 41.1 Phosphorus (ppm) 17.4 7.3 12.8 3.8 29.7 Potassium (ppm) .369.7 85.2 175.5 101.9 58.1 Calcium (ppm) 6850.0 3825.0 5763.4 912.0 15.8 Magnesium (ppm) 258.0 113.3 190.1 66.5 ,35.0 Sodium (ppm) 356.3 21.8 96.9 120.9 124.8 Zinc (ppm) 9.7 1.1 4.2 2.6 61.9 Iron (ppm) 13.4 4.3 6.7 2.6 37.8 Manganese (ppm) 12.4 2.6 6.2 2.7 43.5 Copper (ppm) 2.7 0.6 1.3 0.6 43.0 Wasatch Mountains between American Fork Canyon on the north and the town of San- tacjuin on the south, a distance of 64 km. The chffrose communities selected for study were chosen from the largest and most dense stands in the area and were thought to represent optimal habitat for the species in this part of its range. The Wasatch Mountains are primarily com- posed of sedimentary limestone formations high in calcium carbonate. Rainfall in the area averages 422 mm (NOAA 1922-72), with ap- proximately 280 mm falling between October and April (USDA 1972). The average annual temperature is 10.6 C, with frost-free period averaging 150 days (USDA 1972). Perennial grasses, predominantly blue- bunch wheatgrass {Agropyron spicatiim), make up 65 to 85% of the original plant cover, with shrubs accounting for another 10 to 20%. The dominant shrubs in the area are: gambel oak (Querciis gamhelii), big sagebrush {Artemisia tridentata), bitterbrush (Piirshia tridentata), and snowberry {Symphoricarpos oreophilus) (USDA 1972). Methods Vegetation Ten study sites were selected from the clifiF- rose communities in central Utah. A 10 x 10 m study plot (0.01 ha) was established at each site. Plot boundaries were delineated using a 40-m cord with loops at each corner. Corners were secured by steel stakes. Subsampling was done using twenty 0.25m"' quadrats placed at regular intervals within the study area. Percent cover by species (Daubenmire 1959) and by life form (Ostler et al. 1981) was estimated at each quadrat. Field data were collected during September and October 1981. Maximum annual growth for most spe- cies encoinitered had been reached and the annuals, though dry, were still in place. Individual cliffrose plants as well as branches and twigs were randomly selected for sampling from each site. Average cliffrose twig length (current year's growth) on the in- dividuals was calculated by measuring 3 twigs from 10 branches for a total of 30 measure- ments per study site. Leaves and current-year January 1987 Price, Brotherson: Utah Cliffrose 135 Table 2. A comparison of average nutrient and standard deviation values for cliffrose sites in central I'tali and native plant sites sampled throughout the state. Native plant site •s Soil nutrient factors Cliffrose sites throu; ghout Utah 1* X S T S Nitrogen (%) 0.129 0.053 0. 153 0.09 Phosphorus (ppm) 12.8 3.8 42.1 43.1 Potassium (ppm) 175.5 101.9 329.0 144.1 Calcium (ppm) 5763.0 912.0 7178.0 4457.0 Magnesium (ppm) 190.1 66.5 398.8 196.4 Sodium (ppm) 96.9 102.9 — — Zinc (ppm) 4.2 2.6 2.1 2.3 Iron (ppm) 6.7 2.6 — — Manganese (ppm) 6.2 2.7 — — Copper (ppm) 1.3 0.6 2.1 1.4 *Da(a obtained from Woodward (19S1 1 stem growth were collected and separated for chemical tissue analysis. Tissue mineral con- centrations were obtained for nitrogen, phos- phorus, potassium, calcium, magnesium, zinc, manganese, iron, and copper for both leaf and stem material. Analysis of tissue was performed as described by Graham et al. (1970). Stem cross sections were taken from five randomly selected cliffrose individuals per site to estimate stand age. The cross sections were later sanded and annual growth rings counted to determine stem age (Ferguson 1970). Stem ages were averaged to determine average stand age. Each growth ring was as- sumed to equal one year. Density of cliffrose was determined by counting all plants within the 0.01 ha study plot. Degree of hedging by wildlife was catego- rized using nine form classes: 1 = all available, lightly hedged; 2 = all available, moderately hedged; 3 = all available, heavily hedged; 4 = largely available, lightly hedged; 5 = largely available, moderately hedged; 6 = largely available, heavily hedged; 7 = mostly unavail- able; 8 = unavailable due to height; 9 = un- available due to hedging (Anderson 1974). Soils Three soil samples were obtained from op- posite corners and the center of each plot. Samples were taken from the top 30 cm of the soil profile. The samples were analyzed for texture (Bouyoucos 1951), organic matter (Graham 1948), pH, soluble salts, and mineral composition. Soil reaction was calculated us- ing a glass electrode pH meter. A Beckman electrical conductivity bridge was used to de termine total soluble salts. Determinations for pH and soluble salts were made on 1:1 g/v soil-water paste (Russell 1948). A buffered 1.0 neutral normal ammonium acetate solution was used to extract exchangeable calcium, magnesium, potassium, and sodiinu (Jackson 1958, Hesse 1971, Jones 1973). Zinc, man- ganese, iron, and copper were extracted from the soils using DTPA (diethylene-triamine- pentaacetic acid) extracting agent (Lindsay and Norvell 1969). Ion concentrations were determined using a Perkin-Elmer Model 403 atomic absorption spectrophotometer (Isaac and Kerber 1971). Soil phosphorus was ex- tracted with sodium bicarbonate (Olsen et al. 1954). Total nitrogen analysis was determined bv using macro-Kjeldahl procedures (Jackson 1958). Altitudes were obtained with an altimeter. Percent slope was measured with a clinome- ter. Aspect was determined with a compass. Soil penetrability was measured with a thin steel rod (0.65 cm diameter) which was pushed into the soil as far as possible by hand. Data Analysis Data were analyzed using means, standard deviations, coefficient of variation, and re- gression analyses. Tests were used to deter- mine significant relationships between cliffy rose performance and various environmental factors (Ott 1977). All species were ranked in descending or- der of ubiquity using a constancy x average frequency (C x F) index, and a prevalent spe- cies list was prepared for the cliffrose commu- nity following Warner and Harper (1972). Species diversity was based on MacArthur 136 Great Basin Naturalist Vol. 47, No. 1 © © E'^ © © LU UJ , CO o 9 o , CLIFFROSE LEAF NITROGEN % COVER ANNUAL GRASSES CLIFFROSE HEDGING INDEX 2® © 80-1 r = -0 56 f'=-0 44 > t- 65- Sig levels 05 y=-15 64M+68 40 CO z Q ;."■ ^^ ^^^^ CO f1 IV — IT li. _] 20- ^^^^ (J ■ ^^^- SPECIES DIVERSITY INDEX © idS 0 054 0 063 0 072 0 081 0 090 . CLIFFROSE STEM PHOSPHORUS © CLIFFROSE HEDGING INDEX © SOIL MAGNESIUM (ppm) © -0 66 ^~^ -0 43 Sig evel= 05 ' -17 31, + 99 56 SPECIES DIVERSITY INDEX © •+0 65 r = +0 42 Sis level = 05 -489 15).-25 39 0 145 0 160 0 175 0 190 0 205 0 220 AVERAGE STEM CIRCUMFERENCE YEAR (cm) © <^50 UJ Z '^^ O5 40 il o Zi O 30- O CLIFFROSE HEDGING INDEX Fig. 2. Results of correlation and regression analyses with respect to site factors and vegetation parameters on the cliffrose areas: (A) the relationship between soil gravel and percent shrub cover; (B) the relationship between gravel and phosphorus and potassium in cliffrose leaf tissue; (C) the relationship between soil magnesium and cliffrose cover; (D) the relationship between cliffrose leaf nitrogen and cover of Ag^ropyron spicatum; (E) the relationship between species diversity and cliffrose density; (F) the relationship between species diversity and site disturbance; (G) the relationship between annual grass cover and cliffrose density; (H) the relationship between stem phosphorus in cliffrose and annual grass cover; (I) the relationship between mean stem circumference of cliffrose and understory cover; (J) the relationship between hedging of cliffrose stems and stem nitrogen content; (K) the relationship between hedging of cliffrose stems and shrub cover; (L) the relationship between hedging of cliffrose stems and mean community age. and Wilson's (1963) index. Plant nomencla- ture follows Arnow et al. (1980). Cluster analyses (Sneath and Sokal 1973), using a dendrogram based on the cover contri- butions of various species at the 10 sites, were used to order the study sites. Results and Discussion Environmental Relationships Habitat Relationships. — Cliffrose in our area generally occurred on sites with a south west exposure and an average slope of 43%. January 1987 Price, Brotherson: Utah Cliffrose 137 Table 3. The mean, standard deviation, and coefficient of variation for nutrient ratios between cliffrose organs and soil samples. Large ratios for all nutrients, except calcium, indicate nutrient pumping has been implemented by cliffrose. Nutrients Leaf/soil Stem/soi Leaf/stem Nitrogen Phosphorus Potassium Calcium Magnesium Zinc Manganese Copper .\ = 12.4 s = 5.8 cv = 47.8 X = 55.9 s = 19.2 cv = 40.2 X = 24.1 s = 9.7 cv = 40.2 X = 2.7 s = .6 cv = 22.2 X = 18.2 s = 10.8 cv = 59.3 X = 126.5 s = 52.8 cv = 41.7 X = 8.4 s = 4.7 cv = 56.0 X = 6.9 S = 2.8 cv = 40.6 X - 9.4 S =5.1 CV = 54.3 X = 46.3 S = 17.2 CV = 49.3 X = 22.3 S = 11.0 CV = 49.3 X = 2.3 S = .62 CV = 27.0 X = 10.0 S = 4.1 CV = 41.0 X = 80.3 S = 33.8 CV = 42.1 X = 5.0 S = 2.7 CV = 38.5 S = cv = 7.8 3.0 38.5 X = 1.39 S = .28 CV = 20.1 S CV s CV 1.31 .50 38.2 1.16 .25 21.6 X = 1.12 S = .19 CV = 17.0 X = 1.77 S = .34 CV = 19.2 S = cv = 1.65 .60 36.4 X = 1.71 S = .37 CV = 21.6 S CV .09 10.2 Table 4. A prevalent species list for the study sites. Species are ranked by importance based on the C x F index. Letters in parentheses designate the species life-form class and origin; P = perennial; A = annual; S = shrub; F = forb; C - grass; N = native; and I = introduced. Species Percent constancy Average frecjuency CxF index Percent average cover 1. B ramus tectonim (AGl) 2. Cowania mexicana (PSW) 3. Alyssuin ahjssoides (API) 4. Agropyion spicatum (PGM) 5. Poa secunda (PGM) 6. Bi omits japonictis (AGI) 7. Linaria dcdmatica (PFl) 8. CJinjsothamnus naitseosus (PSN) 9. Sisymbrium altissimum (AFl) 10. Sporoholus cryptandrus (PGM) 11. Erodium cicutarium (AFI) 12. Arteinisia ludoviciana (PFR) 13. Artemisia tridentata (PSN) 100 90.0 9000 36.9 100 64.0 6400 23.7 90 40.0 3600 3.5 80 35.6 2850 4.6 40 31.3 1252 1.4 30 35.0 1050 0.9 10 75.0 750 1.0 60 10.8 650 1.2 50 12.0 600 0.2 20 17.5 350 0.2 10 35.0 350 0.0 40 7.5 300 0.3 60 4.2 250 0.7 Elevation varied little across the sites and av- eraged 1,562 m (Table 1). The communities were located along the gravelly shoreline of ancient Lake Bonneville, which covered much of the western half of Utah appro.xi- mately 12,000 years ago (Bissell 1968). Seven of the sites had gravelly sandy loam soils, two occurred on gravelly loams, and one on a grav- elly clay loam. Soils on the sites were heavily skeletal (48.7% gravel by weight), had an av- 138 Great Basin Naturalist Vol. 47, No. 1 Table 5. A comparison of the mean, standard deviation, and coefficients of variation for mineral content in cliffrose stems and leaves. A paired t-test was used to determine significant nutrient differences between organs. Paired t-test Cliffrose nutrient* Stems Lea\cs significance level X S CV X S CV Nitrogen (%) 1.00 0.20 20.0 1.40 0.10 7.1 .001 Phosphorus (ppm) 0.06 0.02 33.3 0.07 0.01 14.3 NS Potassium (ppm) 0..30 0.07 23.3 0.34 0.05 14.7 .05 Calcium (ppm) 1.30 0.27 20.8 1.40 0.16 11.4 .05 Magnesium (ppm) 0.17 0.04 23.5 0..30 0.90 .30.0 .001 Zinc (ppm) 22.90 6.30 27.5 22.70 5.30 23.3 NS Iron (ppm) 488.40 156.00 31.9 763.70 229.00 30.0 .01 Manganese (ppm) 25.70 4.60 17.9 43.60 10.50 24.1 .001 Copper (ppm) 9.00 1.50 16.7 7.80 0.75 9.6 .01 Table 6. An interregional comparison of plant nutrient concentrations for cliffrose in central Utah, cliSrose in Arizona, and the average of 11 rosaceous plants sampled in Wisconsin. N P K Ca Mg Fe M n Zn Cu . . (%) . . Cliffrose (central Utah) Leaves 1.4 0.07 0.34 1.4 0..30 764 44 23 8 Stems 1.0 0.06 0.30 1.3 0.17 488 26 23 9 Cliffrose (northern Arizona) 1.0 0.06 0..34 1.0 0.12 76 9 19 7 Rose family (Wisconsin)** 1.5 0.28 1..50 1.0 0.48 154 375 44 5 N P K C:a Mg Fe M n Zn Cu . . (%) . (ppm) . . . Soil nutrients (central Utah) 0.13 13 176 5763 190 7 6 4 1.32 (northeast Arizona)* 0.07 11 116 2358 639 5 4 2 0.46 *Data from Fairchild and Brotherson (1980). •Data from Gerloff et al. (1964). erage penetrability of 17.9 cm, and showed an average texture of gravelly sandy loam. Adja- cent finer-textured soils of the old lake bottom apparently create a barrier to many shrubs, including cliffrose, confining them to the well- drained, lighter-textured soils of the foothills. Soil reaction was constant across all sites with the pH being slightly basic (7.7). Cline (1960) showed cliffrose to tolerate pH's rang- ing from 6.8 to 8.7. Soluble salts were low, ranging from 330 ppm to 477 ppm with a mean of 389 ppm (Table 1). Average soil nutrient concentrations in sieved samples are also given in Table 1. Data show sodium concentrations to be the most variable among sites, with calcium being the least variable. Calcium was the most abun- dant essential element in the sampled and nitrogen the least abundant. Our sites were generally lower in all nutrients sampled (ex- cept for the micronutrient zinc) than a broad spectrum of range soils reported by Wood- ward et al. (1984) (Table 2). Because nutrient deficiencies in soils are difficult to document without controlled laboratory conditions, it is important to understand with respect to our cliffrose sites that soil skeletal material re- duces the volume of available nutrient or wa- ter per unit depth of profile (Crowther and Harper 1965). This is because both the nutri- ent and water content of soils are often deter- mined from sieved samples in which particles over 2 mm diameter are removed. Because our soils were so heavily skeletal, nutritional deficiencies on the cliffrose sites may be even more extreme than our data portray. Infiltration rates and depths of percolation of water are highly correlated with soil texture (Croft and Bailey 1964). Gravelly soils allow water to percolate to depths which may only be available to deep-rooted plants. Water per- colation may also leach nutrients to deeper layers. Correlation analysis revealed signifi- cant positive relationships (p < 0.01) between January 1987 Price, Brotherson: Utah Cliffrose 139 shrub cover (primarily cliffrose), stem phos- phorus, and leaf potassium concentrations in cliffrose and percent gravel in the soil (Figs. 2A and 2B). Cline (1960) reports that most lateral branching in the roots of bitterbrush and cliffrose was within the top 30 cm, but when lateral branching occurred at deeper regions in the soil profile, it was extensive and appeared to correlate with increased availabil- ity of moisture and nutrients. The average rooting depth of cheatgrass, our major under- story species, has been reported by Klemmedson and Smith (1965) to be 30 cm. Cline (1960), on the other hand, reported cliff- rose rooting depth to average 120 cm, with the deepest depths reported at 300 cm. These differences may help to explain the positive relationships between mineral concetrations in cliffrose tissue and percent gravel in the soil. The greater the gravel content, the deeper the leaching and the greater the op- portunity for the deep roots of cliffrose to come in contact with and absorb them. Be- cause of the differences in rooting depth, and the fact that the period of most active moisture absorption for cheatgrass is in late fall and early spring (Klemmedson and Smith 1964), a time when moisture in deeper soil profile lev- els is usually abundant, we feel competition for moisture between adult cliffrose individu- als and cheatgrass may be less severe than one might otherwise predict. Competition for available nutrients may also be less than one would normally anticipate. Mineral Nutrient Relationships. — Due to the general absence of soil moisture and low levels of soil nutrient concentrations which are characteristic of cliffrose-dominated sites, cliffrose appears to have evolved strategies enabling it as a species to tolerate infertile environmental conditions. Cliffrose is ever- green and therefore can immediately begin to photosynthesize as soon as winter breaks. The plant flowers in spring, when soils are recharged with moisture and organic matter has been broken down releasing available nu- trients to the soil. Also, since cliffrose is ever- green, its nutrient demands should be much less than for other plants that must recon- struct their foliage each year. Conservation of nutrients and the exploitation of resources during peak supply would favor the survival of cliffrose on pioneer sites (Harper and Buchanan 1982). Deep taproots, with regions of increased lateral branching, would also aid in survival during dry periods. Cliffrose may experience success on sites that are low in nitrogen because of its ability to fix nitrogen (Righetti and Munns 1980, Nelson 1983, Righetti et al. 1986). The insolubility of iron in the alkaline soils of western United States often renders the element unavailable to plants (Mortvedt et al. 1972). Low concentrations of iron were recorded on several of our sites (Table 1). The ratio between iron in cliffrose leaves and the soil where it grows (Table 3) was 127. Ratios for all nutrients, except calcium, were rela- tively high, especially for the macronutrients (Table 3). This demonstrates that cliffrose, like other shrubs (Brotherson and Osayande 1980), has the ability to actively pump nutri- ents. This ability may also help explain how the plant is able to exist on sites that are somewhat nutrient deficient. Positive correlations (p < 0.05) developed between percent cover of shrubs (predomi- nantly cliffrose) and concentrations of stem phosphorus, stem nitrogen, stem copper, and leaf potassium in cliffrose which would indi- cate that where shrub cover is high, cliffrose does its best job of pumping nutrients. Cover of associated understory species also in- creased as soil nutrient concentrations in- creased. Cliffrose cover itself was found to be positively correlated (p < 0.01) with soil mag- nesium (Fig. 2C), yet parent material for the gravels of the cliffrose sites studied was cal- cium carbonate (CaC03). Dolomite (CaC03- MgC03) is relatively scarce in the areas near our study sites, and parent material for the Wasatch Mountains in central Utah is gener- ally low in magnesium. So, local weathering patterns that free magnesium ions into the soil profile may be important to cliffrose ecology. For example, Brotherson et al. (1985) showed the distribution of plant communities to be strongly related to localized weathering pat- terns. Further, plant communities surround- ing Utah Lake in central Utah show exchange- able magnesium concentrations ranging from 247 to 1,039 ppm (Brotherson and Evenson 1981). Brotherson and Evenson's (1981) data show magnesium to become progressively more concentrated in the more highly weath- ered soils as one moves from the mountain foothills to the valley floor, and finally to the lake's edge. 140 Great Basin Naturalist Vol. 47, No. 1 © ® CLIFFROSE AVERAGE COMMUNITY AGE % COVER OF TOTAL VEGETATION © r=-071 LU ^v. r=-0 51 ^^ • Sig le.el- 05 - ^^^ v--004, + 521 >- ^^^ • 0- ^\^ DC LU > 4. ^^^ U O 8- 2- • COVER OF TOTAL VEGETATION © © © % COVER PERENNIALS % COVER ANNUAL GRASSES % COVER Alyssum alyssoides © © o = -0 68 C/5 CD S.q evel = 05 = -06li-f65 /o OC ^" ^\,. ' I ^\,^^ w ^\^^^ DC «0 ^\,_^ HI > Oao. ^"< 20 CLIFFROSE AVERAGE COMMUNITY AGE Fig. 3. Results of correlation and regression analyses with respect to site factors and vegetation parameters on the cliffrose areas: (A) the relationship between average community age and clifirose density; (B) the relationship between cover of total vegetation and site disturbance; (C) the relationship between cover of total vegetation and species diversity; (D) the relationship between perennial cover and exotic cover; (E) the relationship between annual grass cover and cover oiAgropijron spicatum; (F) the relationship between cover oiAltjssum alyssoides and soil silt and clay; (G) the relationship between percent slope and muiiber of annual forbs/stand; (H) the relationship between percent slope and number of species/stand; (I) the relationship between mean community age and shrub cover. The cliffrose sites were dominated in the understory by exotic annuals (Table 4), all of which exploit site moisture and nutrient re- serves at a time of peak availability. These exotics sprout, use up much of the moisture and nutrient reserves, produce seed, and die by the time other plants are emerging from dormancy. Since these exotic annuals are such successful competitors, this could only hap- pen if the overstory and the understory were exploiting different nutrient levels in the soil. Correlation analysis indicated that as the percent cover of bluebunch wheatgrass in- creased, nitrogen concentrations in cliffrose leaves decreased (p < 0.05) (Fig. 2D). Also, cliffrose density was negatively correlated (p < 0.05) with species diversity (Fig. 2E), and species diversity was negatively correlated with site disturbance (Fig. 2F). Further, as cliffrose density increased, percent cover of annual grasses increased ( p < 0.05) (Fig. 2G); and, concurrently, concentrations of phos- January 1987 Price, Brotherson: Utah Cliffrose 141 Table 7. Measurements concerning cliffrose population density, plant age, community age, and plant anatomy. Standard Coefficient Soil nutrient factors* High Low Mean deviation of variation Density (plants/ha) 6700. 0 700.0 24.50.. 5 1851.0 75.5 Average height (cm) 240.0 103.0 171.8 .39.4 22.9 Average community age 68.6 28.3 49.5 13.6 27.5 Individual plant age 162.5 11.1 48.6 28.7 .59.1 Average twig length (cm) 1.3.. 3 2.0 6.3 3.4 54.0 phorus in cliffrose stems increased (p ^ 0.05) (Fig. 2H). Understory cover (predominantly annual grasses) and average increase in cir- cumference per year of cliffrose stems were also positively correlated (p < 0.05) (Fig. 21). These facts tend to indicate a greater competi- tion between cliffrose and deep-rooted peren- nial grasses for moisture and nutrients than between cliffrose and the more shallow- rooted annual grasses. Cliffrose Tissue Chemistry. — The cur- rent annual growth of cliffrose stems and leaves was chemically analyzed for mineral nutrient content. Table 8 compares average nutrient values obtained for cliffrose stems and leaves. Tests for significant differences between stem and leaf nutrients were made using a paired t-test (Ott 1977). Significantly higher concentrations (p < 0.05) of minerals were found in cliffrose leaves than in cliffrose stems for all nutrients analyzed, with the ex- ception of copper, phosphorus, and zinc. Copper concentrations were significantly lower in the leaves, whereas phosphorus and zinc showed no differences. The stem nutri- ent showing the least variability between sites was copper, while iron showed the most vari- ability. Nitrogen concentration in the leaf was least variable, while iron and magnesium were the most variable leaf nutrients. High concentrations of iron were found in both leaves and stems of cliffrose (Table 5). Leaf samples were recollected from all the sites and reanalyzed to check against possible sam- ple contamination. The samples were washed in distilled water, oven dried, and hand ground with a ceramic mortal and pestle. Re- sults of the second analysis confirmed the ac- curacy of the first. Nutrient values obtained for cliffrose in central Utah were compared with values for the species at other geographical locations (Fairchild and Brotherson 1980). Also, the values of this study were compared with analyses for other species of the rose family (Gerloff et al. 1964) (Table 6). The differences between cliffrose nutrient content in central Utah and those in northeastern Arizona are generally small and may be attributed to dif- ferences in the soil nutrient pool. Unfortu- nately, soil data for the Wisconsin study were not available. In comparing cliffrose chem- istry in central Utah with that in northeastern Arizona and with other members of Rosaceae from Wisconsin, one notes tissue iron concen- trations to be highest in cliffrose from central Utah. Soil samples for the Utah and Arizona studies are relatively low in available iron. At present, the high iron concentrations in clif- frose from central Utah remain unexplained. One will also note that average tissue man- ganese for rosaceous species from Wisconsin is much greater than values for either of the cliffrose studies. Soils in the eastern United States are generally acidic, which would make more manganese available for passive absorp- tion. In the West, soils are generally alkaline, which keeps manganese relatively insoluble and unavailable for plant use. Hoffer (1941) points out that nitrogen fixation and ammoni- fication processes are dependent on man- ganese; therefore, soils high in calcium car- bonate are generally deficient in this element. The high differences in manganese concentra- tions between eastern and western United States plants are most likely due to availability in the soil. With the exception of calcium, macronutrient concentrations for cliffrose sites from both Utah and Arizona were lower than average concentrations found for rosa- ceous members in Wisconsin (Table 9). The parent material for the soils of cliffrose in cen- tral Utah and northeastern Arizona are high in calcium. Further research is needed to deter- mine to what extent varying nutrient concen- trations between different species can be at- tributed to natural selection as opposed to inaccurate sampling and analyzing techniques. 142 Great Basin Naturalist Vol. 47, No. 1 % SIMILARITY 10 20 30 40 50 60 70 80 _l I ■ ■ I I 1 1— 90 100 I I t American Fork Canyon Northern Indian Hills Southern Indian Hills North Provo Canyon Santaquin Spring Lake Edgemont-Provo Canyon Jot Rock Canyon Provo River Bottom Springville ^ GROUP ► GROUP II > GROUP Fig. 4. A dendrogram showing cluster groups between study sites based on percent similarity ot species cover by stand. Animal Utilization. — Degree of hedging by wildlife showed a negative correlation (p < 0.05) with percent nitrogen found in the stems of cliffrose (Fig. 2J). This is best explained by the differential stem growth stimulated by varying degrees of plant pruning due to uti- lization. The greater the stem elongation, the more dilute stem nitrogen should become. Data also indicated that the older cliffrose communities were more heavily hedged than the younger communities. Cliffrose utilization increased as percent cover of shrubs on the sites decreased (p ^ 0.05) (Fig. 2K). Also, utilization increased as community age of the cliffrose stands in- creased (p < 0.05) (Fig. 2L); and as the age of the cliffrose stands increased, cliffrose density decreased (p ^ 0.05) (Fig. 3A). Density mea- surements revealed central Utah cliffrose communities to have an average of 2,451 plants per hectare (Table 7). The average height of cliffrose on our study sites was 171.8 cm, with the shortest community averaging 103 cm and the tallest 240 cm (Table 7). In- creases in utilization of the older cliffrose stands can most likely be attributed to older communities having fewer plants, which would tend to increase the grazing pressure per plant. Further, the large plants should provide better thermal cover, as well as better escape cover, thus providing incentive for ani- mals to concentrate in their vicinity with re- sultant higher use. Community Relationships Community Structure. — A percent simi- larity index between communities was calcu- lated using data based on measurements of cover. Cluster analysis was then used to group the cliffrose stands. The cluster based on cover of individual species showed the sites to have an average percent similarity of 42.8% (Fig. 4). The den- drogram (Fig. 4) shows three relatively dis- tinct groups. Cover data for stands in Group I, Group II, and Group III were averaged (Table 8). Group I had the greatest cover and was dominated by exotic annuals, mainly cheat- grass. Group II had the next greatest cover and was also dominated by annuals, but less so than in Group I. Percent perennial cover in Group II was slightly higher than in Group I, but cliffrose cover remained constant. Data showed the major life form for Group III to be perennial grasses. Unlike the other cliffrose study sites, this stand recorded few annuals during our original investigation. However, when reexamined in the spring (1982), spots originally recorded as bare ground were found to be heavily covered by the small introduced annual, jagged chickweed {Holosteum umbel- January 1987 Price, Brotherson: Utah Cliffrose 143 Table 8. Cliffrose study sites as grouped by cluster analysis. Sites are grouped based on percent similarity of the averaged percent cover contributed by prevalent species. Figure 3 shows American Fork Canyon-Northern Provo Canyon in Group I, Santaquin-Provo River Bottom in Group II, and Springville in Group III. Letters in parentheses designate the species life-form class and origin: P = perennial; A = annual; S = shrub; F = forb; G = grass; N = native; and I = introduced. Species Group I Group II Group III 1. Bromus tcctontm (AGI) 2. Cowania mexicana (PSW) 3. Ahjssum ah/ssoides (AFT) 4. Agropyron spicatum (PGM) 5. Poa secunda (PGM) 6. Bromus japonicits (AGI) 7. Linaria dalmatica (PFI) 8. Chrijsothammis nauseosiis (PSN) 9. Sisymbrium (dtissimum (AFI) 10. Spurobolus cryptandrus (PGM) 11. Erodium cicutarium (AFI) 12. Artemisia ludoviciana (PER) 13. Aiicmisia tridentata (PSN) Total cover 61.0 26.0 7.0 2.3 0.3 0.2 0.0 3.1 0.5 0.0 0.1 0.1 1.0 102.1 0.4 3.5 0.3 11.5 10.5 0.0 0.0 0.0 0.0 0.0 0.0 2.3 3.1 .32.1 latum). According to Arnow et al. (1980), the plant grows on highly disturbed sites. Jagged chickweed was not found established to any degree of significance on any of the other sites following reexamination. In spite of this addi- tion, Group III was distinctly different from the other groups in terms of plant cover com- position. Total cover values and species com- position showed major differences among the three groups (Table 8). Diversity. — Diversity has two conceptual aspects that deserve attention: (1) the niunber of species per unit area and (2) the evenness of abundance among the species present. Com- munity diversity (MacArthur and Wilson 1963) on our sites varies from a high of 4. 1 to a low of 1.7, with a mean of 2.8 (Table 9). The low figure was correlated with the highest incidence of cheatgrass on a site and indicates that only a few species were contributors to the vegetative composition. The high figure was associated with a site which had little cheatgrass cover and where several species were shown to contribute to the vegetative cover. Assuming the cover contributed by exotics to be highly correlated with the degree of site disturbance (Klemmedson and Smith 1964), we formulated a disturbance index based on the amount of cover contributed by intro- duced species on our sites. Correlation analy- sis showed a positive relationship (p < 0.01) between the site disturbance index and per- cent cover of total vegetation (Fig. 3B). Fur- ther, a negative correlation (p < 0.05) was found between species diversity and total plant cover (Fig. 3C). As the site disturbance index increased, species diversity decreased (Fig. 2F). It appears, therefore, that site dis- turbance has tended to promote low diversity in the vegetation on our sites by allowing in- troduced annuals to invade into open areas where they complete their growth in the early spring while soil moisture is still abundant. The increased competition from the intro- duced exotics would have a crowding effect on other species and thus lead to an eventual decrease in diversity. The prevalent species for the cliffrose sites in central Utah are listed in descending order based on the C x F index (Table 4). Again, the importance of exotics on our sites is illus- trated. Cheatgrass (Bromus tectorum) is the most common species on the list, followed by cliffrose and madwort {Ahjssuin alyssoides), an introduced annual from Europe (Arnow et al. 1980). Nearly half the species on the list (6 out of 13) are introduced exotics (Table 4), all of which are extremely successful on dis- turbed sites. The data showed an average of 7.6 perennials and 3.9 annuals per stand, yet annuals contributed almost half the total cover (Table 9). Significant negative correlation (p ^ 0.01) also occurred between cover of perenni- als and cover of exotics (Fig. 3D), suggesting that perennials must decline before invading exotics can become abundant. The correlation between cover of annual grasses and the 144 Great Basin Naturalist Vol. 47, No. 1 Table 9. Highs, lows, means, standard deviations, and coefficients of variation for various biotic factors and life-form classes associated with the cliffrose sites in central Utah. Standard Coefficient Factors High Low Mean deviation of variation % Total vegetative cover 80.0 .33.8 .59.7 13.9 23.3 % Exposed rock .34.1 3.1 20.1 9.7 48.3 % Bare ground 12.8 0.0 5.8 5.0 86.2 % Litter 26.4 6.6 14.8 6.4 43.2 % Mosses 13.4 0.0 3.1 4.9 158.1 % Lichens 4.1 0.0 1.3 1.4 107.7 % Trees 1.1 0.0 0.2 0.4 200.2 % Shrubs 60.3 20.2 35.4 12.2 34.5 % Perennial forbs 17.7 0.0 3.2 6.1 190.6 % Annual forbs 14.0 0.0 4.4 4.9 111.4 % Perennial grasses 65.9 0.0 11.9 19.8 166.4 % Annual grasses 74.4 1.1 45.1 19.7 43.7 % Perennials 96.6 23.5 50.5 20.9 41.4 % Annuals 76.5 3.4 49.5 20.9 42.2 % Exotics 76.1 3.4 51.1 20.7 40.5 # Perennials/study site 11.0 2.0 7.6 2.5 32.9 # Annuals/study site 7.0 2.0 3.9 1.6 41.0 # Shrubs/study site 6.0 2.0 3.8 1.3 34.2 # Species/study site 16.0 5.0 11.5 3.2 27.8 Species diversity index* 4.1 1.7 2.8 0.8 28.6 *MacArthur-Wilson (1963) diversity index perennial bluebunch wheatgrass {Agropijron spicatwn) was also negative (p < 0.01) (Fig. 3E). The distribution on our sites of the annual forb madwort is positively correlated (p < 0.01) with percent silt and percent clay in the soil (Fig. 3F). This relationship can most likely be attributed to the moisture and nutrient factors associated with finer-te.xtured soils. The number of annual forbs on a site generally increased as the slope steepness increased (p ^ 0.05) (Fig. 3G). Also, the number of species per study site increased as slope steepness increased (p < 0.05) (Fig. 3H). This would indicate that the sites on the steeper slopes have more microhabitats and are probably less disturbed. The correlations may also be related to the reluctance of domestic grazing animals, the major disturbing influence of the past on these sites, to make use of the steeper slopes. Life Forms. — Cliffrose sites typically show environmentally stressed conditions related to such things as extremes in moisture, tem- perature, and soil nutrients. Plants that are successful on the sites are generally able to withstand a broad range of environmental fluctuations, or, as in the case of annuals, they complete their life cycles during hospitable times of the year. Of the total cover that aver- aged 59.7%, annual grasses contributed the largest part with 45.1%, shrubs furnished 35.4%, perennial grasses contributed 11.9%, annual forbs accounted for 4.4%, and peren- nial forbs contributed only 3.2% (Table 9). Gambel oak (Qiiercus gambelii) was the only tree found on the sites, and it played an in- significant role in the vegetation. Perennials contributed 50.5% of the total cover, while annuals contributed 49.5%. Averaging the constancy x frequency (C x F) index values of Table 4, we found annual grasses to be twice as important in the community as shrubs (Table 10). The C x F index reflects the unifor- mity with which individuals of a species are distributed across the site sampled rather than the amount of biomass produced. The values show annual forbs to be slightly more important than perennial forbs or perennial grasses in the community. Annuals (Table 10) were shown to have a higher prominence in the community than perennials. Cliffrose Age and Community Struc- ture.— Cliffrose plants of varying basal cir- cumferences were aged. Linear regression was used to establish an age-circumference relationship (Fig. 5). This relationship had an r" value of +0.73 and was significant at p ^ 0.001. The prediction equation for the rela- tionships is Y = 4.73 (basal circumference) + 5.45. The average variation about the y-axis is ±6.7 years. January 1987 Price, Brotherson: Utah Cliffrose 145 Table 10. Life forms listed in order of importance to the vegetative composition. Values were obtained by averaging the product of percent species constancy be- tween sites and percent species frequency within sites for species of each life-form class. Life forms Constancy x frequency index Annual grasses Shrubs Annual forbs Perennial grasses Perennial forbs Total annuals Total perennials 5025 2433 1517 1483 525 6542 4441 Basal circumference measurements (30 per site) were randomly obtained for 9 of the 10 communities. The Springville community had only 18 living cliffrose plants. From these basal measurements, the plants of each stand were aged. By combining the estimated ages of the 288 plants studied, we constructed a histogram to show the general age distribu- tion of cliffrose in central Utah (Fig. 6). The X-axis of the histogram shows the age classes (in 5-year intervals) and the year correspond- ing with the period of establishment for the age class. The y-axis is the number of plants found within each age class. The histogram shows the median cliffrose age to be between 25 and 30 years. The youngest plant found in any of the communities was 11 years, the old- est was 163 years, and the average age was 48.6 years (Table 7). The youngest average community age was 28.3 years, the oldest 68.6, and the mean was 49.5 years (Table 7). Cliffrose Establishment. — The his- togram indicates that since about 1957 there has been a steady decline in the establishment of cliffrose in central Utah. The graph also shows a substantial decline in numbers of new plants between the years 1942 and 1947. Cor- relation analysis showed the percent cover by shrubs (predominantly cliffrose) decreased as the average community age of cliffrose in- creased (p < 0.05) (Fig. 31). The older cliffrose stands do not appear to be replacing them- selves with younger plants (Figs. 3A and 6). Reasons for establishment failure most likely represent a combination of factors. Some possible explanations should include: (1) cliffrose is cyclic in its establishment, (2) seed predation by rodents may be high, (3) plant diseases may be eliminating seedlings. 112-1 105- 98- 91 84- LU W 77- O F 70 49- 42- 35 28 21 14 r = -1-0 85 r2 = -1-0 73 Sig level =001 y = 4 73X-I-5.45 5 1 8 9 12 7 16,5 20 3 24 1 27 9 31 7 35 5 39 3 43 1 CLIFFROSE STEM CIRCUMFERENCE (cm) Fig. 5. The relationship between the circumference (cm) of cliffrose stems and the number of annual growth rings counted (age) of 50 cliffrose plants sampled. (4) insects and/or small mammals may destroy seedlings, (5) climate may currently be unfa- vorable, (6) intraspecific competition between age classes may be extreme, (7) interspecific competition, (8) establishment requires tram- pling and utilization of the sites by livestock and wildlife, and (9) reproduction may be de- stroyed by fire. Concern that small seedlings were over- looked during the initial data collecting period led us to reexamine all of the sites to confirm original findings. No seedlings were discov- ered at this time. Neither were seedlings found in any of the 200 0.25 m" quadrats used to estimate plant cover. Cyclic Establishment: According to Alexan- der et al. (1974), cliffrose produces a good seed crop every 2 years, and young plants begin bearing seed as early as 5 years. Figure 7 is a graph comparing annual rainfall patterns with the number of cliffrose plants established each year during a 50-year period (1922- 1972). Precipitation data were smoothed out using a 10-year running average to eliminate the visual impact of extremely high or low years and to emphasize long-term trends (Croft and Bailey 1964). In comparing precipi- tation and establishment trends, it appears that increases in rainfall may reduce cliffrose seedling success. The observed decline in 146 Great Basin Naturalist Vol. 47, No. 1 < _i o I LU o < 40-1 30- 20- LU (/) O CL Li. o D -Th-fh — r- 150 O,'' .'i> ' ■ ' ' ^ 25 50 75 100 125 —I 175 .O^ N \^ v^ ^^ CLIFFROSE AGE AND CORRESPONDING YEAR Fig. 6. A histogram depicting the establishment success and trend of cHffrose over the last 175 years. Fig. 7. A graph depicting the relationship between precipitation trends and cliffrose establishment success and trend over a 50-year period. plants established between the years 1942 and 1947 (Fig. 6) was a peak rainfall period for the area considered. Comparison of the last 25 years for precipitation per year versus cliffrose establishment suggests that diminishing seedling success may be somewhat related to cyclic rainfall patterns. Predation: Seed and seedling predation by rodents is a subject addressed in several pa- pers. Alexander et al. (1974) note that clusters of new cliffrose seedlings are quite common due to rodent caches. Young and Evans (1981) state that if caches are not found by rodents, the seedlings will die from intraspecific com- petition. They also point out that the rodent will often miss a seedling or two, which allows for plant establishment. Seed predation by rodents may in reality enhance species disper- sal and establishment. Disease: Lack of knowledge concerning dis- eases of cliffrose dictates that little be said concerning this subject. No papers addressing the topic were found in the literature. How- ever, an exceptionally high rate of mortality has been noted for greenhouse-grown seedlings of both cliffrose and bitterbrush due to damping-oflP fungi. Though damping-off is common among greenhouse stock, bitter- brush and, even more so, cliffrose seemed to be especially susceptible to such diseases (B. L. Welch, personal communication). Cliffrose susceptibility to damping-off under natural conditions is not known. This could be an laniiarv 1987 Price, Brotherson: Utah Cliffrose 147 explanation for the apparent inverse relation- ship found between ehffrose estabhshment and average annual precipitation. Insects: The impact of insects and their rela- tionship with cliffrose is also not well known. Again the literature revealed no studies on the subject. Although little is known concerning the subject, insect predation should not be completely ruled out as a possible infhiencing factor. Climate: Drought, as a possible explanation for the lack of seedling establishment in cliflP- rose since 1957, is not a good choice. Over the centuries, cliflProse has adapted to an environ- ment which is, at times, extremely dry. Cli- matology records (NOAA 1922-1972) show that during the major periods of decreasing seedling establishment, average precipitation was above the normal amounts recorded for preceding years. Competition: Intraspecific competition probably has little to do with the downward trend in recent years. It is difficult to imagine that a species which has been successfully established for hundreds of years would sud- denly begin outcompeting itself into possible local extinction. However, numerous studies have been published (interspecific competition) dealing with the extreme competitiveness demon- strated by exotic annuals (Stewart and Hull 1949, Pi'emeisel 1951, Holmgren 1956, Klemmedson and Smith 1964, Young et al. 1972, Giunta et al. 1975, Mack 1981, Mack and Pyke 1983), particularly cheatgrass. Cheatgrass invasion into Utah is fairly re- cent, having been introduced aroimd the turn of the century (Klemmedson and Smith 1964). Studies show that cheatgrass successfully out- competes weeds and perennial grasses which are slow growing or spring germinating (Piemeisel 1951, Stewart and Hull 1949). Evans et al. (1967) state that cheatgrass consis- tently closes stands to the establishment of perennial grass seedlings. Warg (1938) and Hulbert (1955) obtained success for cheat- grass germinations (under optimum condi- tions) as high as 99.5%. The density obtained by cheatgrass can vary greatly, depending on the conditions. Stewart and Hull (1949) found cheatgrass to vary from 1,080 to 15,000 seedlings per m"". This gives an idea ot the potential competition for moisture that cheat- grass can exert if conditions are favorable. Studies by Giunta et al. (1975) showed that in cheatgrass stands success in the germina- tion and establishment of cliffrose was in- creased as width of soil scalps increased. They also showed the average number of cliffrose plants surviving after five years in a 100- linear-foot row to be 5, 13, 19, and 59 with scalp widths of 4, 8, 16, and 24 inches, respec- tively. Holmgren (1956) worked with bitter- brush. He stated that high mortality occurred in the better seedling stands during the first year or so after germination. Holmgren (1956) also states that moisture at the time of germi- nation and during the initial growth period is probably the most crucial factor associated with bitterbrush seedling success. Holm- gren's (1956) study shows bitterbrush germi- nation rates for study plots that were cleared of all competition to be 90%, with 66% surviv- ing after the first year. Plots in which only broadleaf weeds were allowed had a 91% ger- mination, with 48% surviving the first year. Where only cheatgrass was allowed, germina- tion was 46%, with 0% surviving after only three months. Holmgren (1956) then con- cludes, "Tn cheatgrass stands, few bitterbrush seedlings are able to survive the first summer. The competitive effect of cheatgrass generally becomes manifest early in the growing sea- son, coinciding with its period of rapid growth.' According to Young and Evans (1981), even under optimum conditions germination of cliff'rose rarely exceeds 60%. They credit the lack of success to the amount and type of dormancy found in the seeds and suggest that an ideal field stratification environment for cliffrose seeds is one with constant moisture near field capacity and a temperature of 0 to 5 C. Therefore, the environmental require- ments for success in cliflFrose germination and the potential response of cheatgrass when these conditions are obtained may well ex- plain the apparent negative relationship of cliffrose with average annual rainfall. Compe- tition between cliffrose seedlings and cheat- grass may become highly intense during years of increased average annual precipitation and therefore help explain the lack of cliflFrose es- tablishment on our sites in recent years. Other introduced annuals of prevalence were madwort (averaging 3.5% cover) and Japanese chess (Bromusjaponicus) {averagmg onlv 1%, but found well established on some 148 Great Basin Naturalist Vol. 47, No. 1 sites). Original data (collected in the fall) showed storksbill (Erodium cicutarium) to play a minor role in the cover composition (Table 4). However, when sites were reexam- ined in the spring, some communities had significant quantities of storksbill and jagged chickweed in their understory. Disturbance: Practically all 10 study sites have a history of extensive grazing pressure by sheep, cattle, and wildlife. Because they fur- nish food and shelter, cliffrose stands would tend to concentrate livestock and wildlife. Such disturbance would open the sites to cheatgrass invasion and establishment. Studies conducted by Cook and Harris (1952) showed that when cheatgrass was in the dough stage (usually around May) and turning purple, sheep ate the entire plant down to one-half inch above the ground. Hull and Pechanec (1947) observed that cattle and horses ate dry cheatgrass readily if ample wa- ter were available, and both cattle and sheep ate dry cheatgrass in the winter. Stewart and Hull (1949) estimated that cheatgrass utiliza- tion as low as 35 to 40% would allow reestab- lishment of perennial cover. Increased utiliza- tion and disturbance of cheatgrass, due to the higher concentration of grazing animals, would most likely aid in the establishment of cliffrose by trampling its seed into the ground and reducing the competition for moisture between cliffrose seedlings and cheatgrass. However, since livestock grazing permits on most of the study sites were revoked in 1957, cliffrose establishment by increasing utiliza- tion of cheatgrass is not a good choice to ex- plain the success or failure of seedling success. In fact, 1957 is the same year the histogram in Figure 6 shows the success of cliffrose seedlings beginning to decline. Fire: Many of the exotic annuals grow in dense stands where they generally complete their life cycle early in the growing season and then become dry and susceptible to summer wildfires. Young et al. (1972) say, "The fuel provided by early maturing, highly flammable alien annuals contributes to the incidence and spread of these species." McCulloch s (1969) study showed cliffrose stands to be drastically reduced by fire. Fire carried by a dense stand of dried exotic annuals was responsible for destroying over half the cliffrose community on the study plot in Springville. Where the fire had swept, no cliffrose plants survived. Cliffrose Management. — Cliffrose seed- lings, when allowed relative freedom from annual competition throughout the first grow- ing season, have highly increased establish- ment success. It is believed decadent cliffrose communities could be rejuvenated by reduc- ing competition as seldom as once every 10 to 15 years. Areas that might be considered for effective competition reduction are biological, me- chanical, and chemical. Concentrated grazing to increase soil disturbance and cheatgrass utilization may in some areas have practical application. Increasing seedling success by mechanically placing scattered soil scalps within cliffrose communities could also prove to be an effective managment practice. In the past, few methods have been suc- cessful in controlling cheatgrass and other ex- otic annuals (Young et al. 1972). In recent years cheatgrass control with chemicals has received attention. Though not feasible for extensive rangeland control, chemicals have real promise in enhancement of perennial grasses and browse species (Klemmedson and Smith 1964). Summary AND Conclusions Data indicate cliffrose site preference in central Utah is highly consistent. Cliffrose communities are generally located on steeper slopes which are exposed to environmental extremes. Soils associated with cliffrose are relatively low in most macronutrients and some micronutrients. Vegetative composition is dominated by e.xotic annuals (predomi- nantly cheatgrass) with shrubs (predomi- nantly cliffrose) being the next important life form. From the data it appears that competi- tion for resoiuces is less severe between ma- ture cliffrose plants and annuals than between cliffrose and perennials. The nutrient concen- trations in cliffrose tissue, relative to soil con- centrations, indicate nutrient pumping has been implemented for adaptation to nutrient- poor sites. Age distribution of cliffrose shows a decline in successful seedling establishment over the last 25 years. Data from this study and others indicate that the major contribut- ing factor responsible for the decline is com- petitive exclusion by exotic annuals (mainly cheatgrass). Destruction of cliffrose by fire due to dense stands of exotic annuals may also January 1987 Price, Brotherson: Utah Cliffrose 149 explain how exotic annuals eliminate plants competing with them tor environmental re- sources. The negative factors influencing de- terioration of cliffrose populations are most likely amplified in central Utah when cliffrose is at the northern edge of its natural range. Since habitat for cliffrose in central Utah is less than optimal, if cliffrose communities are to be maintained or enhanced, special atten- tion to their management must be considered and implemented. Literature Cited Alexander, R. R., K Jorgensen, and A. P Plummer. 1974. Coivania mexicana variety stansburiana (Torr.) Jepson (Cliffrose). Pages 353-355 in C. S. Schopmeyer, tech. coordinator. Seeds of woody plants in the United States. USDA, Forest Ser- vice. USDA Agric. Handbook 450. 883 pp. Anderson. D L. 1974. Ecological aspect of Ccrcocnrpr/.s montaiius Raf communities in central Utah. Un- published thesis, Brighani Young University. 84 pp. Arnow. L , B. Albee, and A. Wyckokf. 1980. Flora of the central Wasatch Front, Utah. University of Utah Printing Service. Salt Lake City, Utah. 663 pp. Bkssell. H J 1968. Bonneville — an ice-age lake. Brighani Young Univ. Geol. Studies. Vol. 15, Part 4. 65 pp. Blauer. a. C . A. P. Plummer, E. D. McArthur. R Stevens, and B. C. Giunta. 1975. Characteristics and hybridization of important intermountain shrubs. I. Rose family. USDA, Forest Service, Research Paper INT- 169. BoUYOUCOS. G J 1951. A recalibration of the hydrometer method for making mechanical analysis of soils. Agron. Journal 43: 4.34-438. 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The American Society of Agronomy and National Fertilizer Association, Washington, D.C. 327 pp. Holm(;ren, R. C. 1956. Competition between annuals and young bitterhru.sh (Purshia tridentata) in Idaho. Ecology 37: 371-377. HuLBERT, L. C. 1955. Ecological studies oi Bromiis tcctn- rtim and other annual lirome grasses. Ecol. Monog. 25: 181-213. Hull, A. C ,Jr , .andJ F Pechanec 1947. Cheatgrass — a challenge to range research. J. Forestry 47: 555-564. Isaac, R. A , and J D Kerbkr 1971. Atomic absorption and flame photometry: technicjue and uses in soil, plant, and water analysis. Pages 17-38 in L. M. Walsh, ed., Instriunental methods for analysis of soils and plant tissues. Soil Sci. Soc. Amer., Madison, Wisconsin. Jackson, M L. 1958. Soil chemical analysis. Prentice- Hall, Inc., Englewood CliHs, New Jersey. Jensen, C H , andG. W Scoitek 1977. A comparison of twig-length and browsed twig methods of deter- mining browse utilization. J. Range Manage. 30: 64-66. Jensen. C. 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Mack, R N , and D A Pyke 1983. The demography of Bromus tectorum: variation in time and space. J. Ecology 71: 69-93. McArthur, E. C . H. C. Stutz. and S. C Sanderson 1983. Taxonomy, distribution, and cytogenetics of Purshia, Cowania, and FaUugia (Rosoideae, Rosaceae). Pages 4-24 in A. R. Tiedemami and K. L. Johnson, conips.. Research and management of bitterbrush and cliflrose in western North Amer- ica. USDA, Forest Service Gen. Tech. Rept. INT- 152. Ogden, Utah. 279 pp. McCulloch, C Y 1966. CJliffrose browse yield on bull- dozed pinyon-juniper areas in northern Arizona. J. Range Manage. 28: 435-444. 1969. Some effects of wildfire on deer habitat in pinyon-juniper woodland. J. Range Manage. 33: 778-784. 1971. Cliffrose reproduction after pinyoTi-juniper control. J. Range Manage. 24: 468. 1978. Statewide deer food preference. Arizona Game and Fish Department. Research Division. Phoenix, Arizona. 29 pp. McMiNN, H. E. 1939. An illustrated manual of California shrubs. University C^alifornia Press, Berkeley and Los Angeles. 663 pp. MoRTENSON.T H 1970. Ecological variations in the leaf anatomy of Fallw^ia. Endl., Cowania, D. Don, Purshia D. C, and Cercocarpus H. B. K. (Rosaceae). Unpublished dissertation, Clareniont College, Clareniont, California. 778 pp. MoRiA'EDT. J. J.. P. M. Giordano, and W. L Lindsay. 1972. Micronutrients in agriculture. Soil Sci. Soc. Amer., Inc., Madison, Wisconsin. 666pp. Nefe, D J 1978. Effects of simulated use on the vigor of browse plants. Arizona Game and Fish Depart- ment. Research Division. No. W-78-R. Phoenix, Arizona. 26 pp. Nelson, D L 1983. Occurrence and nature of acti- norhizae on Cowania stanshuriana and other Rosaceae. Pages 225-239 in A. R. Tiedemann and K. L. Johnson, comps.. Research and manage- ment of bitterbrush and cliffrose in western North America. USDA, Forest Service, Gen. Tech. Rept. lNT-1.52. Ogden, Utah, 279 pp. NOAA 1922-1972. Annual climatic summaries for Utah (Provo Station). 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ARR-W- 17. ,39 pp. Young, J. A, R A Evans, and J Major. 1972. Alien plants in the Great Basin. J. Range Manage. 25: 194-201. ALPINE VASCULAR FLORA OF THE RUBY RANGE, WEST ELK MOUNTAINS, COLORADO Emily L. Hartman and Mary Lou Rottnian Abstract — The Ruby Range is a northern extension of the West Elk Mountains of west central Colorado. Composed primarily of sedimentary rocks, the range is heavily faulted and intruded by many dikes and sills. Eight study areas, selected as representative of the major topographic features of the range, were analyzed floristically. A vascular flora of 220 species in 111 genera and 35 families is reported. The phytogeographic distribution of the flora is primarily alpine and western North American. The flora of the Ruby Range shows a 74% similarity to the flora of the San Juan Mountains to the southwest. The Ruby Range, a northern extension of the West Elk Mountains (Prather 1982) of west central Colorado, is west of the Conti- nental Divide between 107 degrees 05 min- utes and 107 degrees 07 minutes West longi- tude and 38 degrees 52 minutes and 39 degrees North latitude. This discrete range extends 15.2 km northward from its southern boundary, 18.5 km northwest of Crested Butte, Gunnison County. In outline the range resembles the letter h with the vertical line being formed on the west by a series of 11 mountain peaks ranging in elevation from 3,573 to 3,982 m. The curved part of the letter represents an escarpment and its southeast- ern terminus ranges from 3,664 to 3,780 m. Glacial effects are evident in the present alpine landscape as cirques, tarns, hanging valleys, basins, rock steps, and broad U- shaped valleys in the lower elevations. The Ruby Range is composed primarily of sedimentary rocks intruded by many dikes and sills. The sedimentary formations in- clude: Mancos Shale, a silty marine shale in- terbedded with silty sandstone, sandy lime- stone, and carbonaceous shale of Upper Cretaceous age in the north; Mesa Verde, interbedded sandstone, shale, coal, and car- bonaceous shale of Upper Cretaceous age in the central part; and Wasatch, evenly bedded sandstone, siltstone, and conglomerate of Eocene age in the south. The Mancos Shale is locally metamorphosed to hornfels, whereas the Wasatch is generally metamorphosed to quartzite, argillite, and silty and argillaceous hornfels. A large number of dikes and sills composed of either quartz monzonite por- phyry, granodiorite porphyry, or dacite por- phyry are intruded into the sedimentary for- mations. Stocks of quartz monzonite porphyry form the summits of four of the mountains in the range (Gaskill et al. 1967). There are nu- merous fault zones and talus deposits in the range. A floristic study of the subalpine and alpine zones in Robinson Basin was made by Bathke (1968). Collections were made in the Ruby Range during the summers 1980-1985. Nomencla- ture in the checklist follows Kartesz and Kartesz (1980). Voucher specimens are de- posited in CU-Denver. Phytogeographic ab- breviations used in the annotated checklist of vascular species are identified in the discus- sion section. Study Areas Eight study areas representative of the ma- jor topographic features and distributed throughout the length of the Ruby Range were selected. Northeast-facing cirque basins of Mount Owen, Purple Peak, and Augusta Mountain are the highest in elevation, rang- ing from 3,660 to 3,843 m. Baxter, Robinson, and Redwell basins are drainage basins of the Slate River, a tributary of the Gunnison River. The elevational range of the upper parts of these basins is 3,556 to 3,599 m. Scarp Ridge, a northwest-southeast-trending escarpment ranges in elevation from 3,664 to 3,725 m. The south- and southwest-facing convex slopes of Mount Emmons, which forms the southeast Department of BiologA,', University of Colorado, Denver. Colorado 80202 152 January 1987 HaRTMAN, ROTTMAN: COLORADO AlPINE FLORA 153 terminus of Scarp Ridge, range in elevation from 3,698 to 3,780 m/ Climatic data are lacking from the study area. The nearest U.S. Weather Bureau sta- tion is Crested Butte at 2,701 m elevation to the east. Only generalized climatic informa- tion for the Ruby Range can be extrapolated from this station. Two precipitation maxima occur: July to September, and January (Lan- genheim 1962). Heavy snowfall in the winter renders the area inaccessible from November through June. Permanent snowbanks are common on northeast-facing exposures in the higher elevations. The prevailing winds are from the west and southwest. Wind velocities approaching 92 kph are not uncommon in the alpine throughout the summer (Bathke 1968). Plant Communities Meadow Communities The moist meadow community type is most representative of the tundra in the Ruby Range. This contrasts with the predominant dry meadows of the Front Range and corre- lates with the San Juan Mountains which, like the Ruby Range, experience a higher mois- ture regime (Hartman and Rottman 1985). In many places the uniformity of the turf meadow is interrupted by talus deposits and tailings associated with old mining activity. Moist meadow communities on slopes are dominated by Deschampsia caespitosa and Geum rossii var. turbinatiwi, whereas Carex nigricans and Jiincus drummondii dominate the community type in flat areas. Dry meadow communities occur on steep, rocky, convex slopes which experience early snowmelt or adjacent to bedrock outcrops. The most frequent dominants include Agropyron trachycaidinn var. latighime, Danthonia intermedia, Geum rossii var. tur- binatian, and Ivesia gordonii. Kobrcsia myosuroides, the overwhelming dominant of dry meadows and climatic climax species of the Front Range (Marr 1961, Eddleman and Ward 1984), is highly restricted in occurrence in the Ruby Range. Langenheim (1962) found the same to be true in the adjacent Elk Moun- tains near Crested Butte. Carex elynoides, a dry meadow dominant and substitute for Ko- bresia in the San Juan Mountains (Hartman and Rottman 1985), is restricted in occurrence to fellfields in the Ruby Range. The dominants foimd in wet meadows adja- cent to ponds are Caltha leptosepala, Carex illota, and Carex praeceptorum. On slopes and in association with rivulets the wet meadow dominants are Caltha leptosepala and Corydalis caseana ssp. brandegii. Fellfield Community Fellfields are restricted to ridgetops and the top surface of bedrock outcrops. This com- munity type may show a lack of dominants or may have Ivesia gordonii as the dominant spe- cies. The typical fellfield cushion plant com- munity, dominated by Paronychia pulvinata and Phlox caespitosa ssp. condensata, on windswept sites of the Front Range (Cox 1933, Eddleman and Ward 1984) and Sangre de Cristo Range (Soil Conservation Service 1979) is absent in the Ruby Range. Talus Community Talus communities in the Ruby Range, like those of the Mosquito Range (Hartman and Rottman 1985), are characterized by a lack of dominants and a high diversity of total species present, reflecting the opportunistic nature of many tundra species (Schaack 1983). Any number of 83 species may be found in various talus communities. Krummholz Community Timberline, in the form of krummholz, is variable ranging from 3,538 to 3,729 m with the lower elevations found on easterly expo- sures and the higher on southerly exposures. This ecotonal community has representative species from both the alpine and subalpine zones. Krummholz conifers, Abies lasiocarpa and Picea engehnannii, are equally co-domi- nant. Shrub Tundra Community The shrub tundra community is very patchy and restricted to moist depressions and drainage areas. This community is dominated by thickets of Salix brachycarpa and Salix glauca var. villosa which exert a primary influ- ence on the surrounding environment and associated species. Discussion The alpine flora of the Ruby Range consists of 220 vascular plants: 213 species represent- 154 Great Basin Naturalist Vol. 47, No. 1 ing 104 genera of angiosperms, 3 genera and 3 species of gymnosperms, and 4 genera and 4 species of pteridophytes. The family with the greatest number of species is Asteraceae with 34 species. Other families with a large repre- sentation are Cyperaceae, Poaceae, Brassi- caceae, Caryophyllaceae, Saxifragaceae, and Rosaceae with 23, 19, 17, 15, 12, and 11 taxa, respectively. In comparing the seven leading families found in the Ruby Range to those found in the San Juan Mountains, southwestern Colorado (Hartman and Rottman 1985); Mosquito Range, north central Colorado (Hartman and Rottman 1985); and Indian Peaks area of the Front Range, northern Colorado (Komarkova 1976), only the exclusion of the Scrophulari- aceae and inclusion of the Rosaceae are noted; however, the rank order varies somewhat with each range. Although there is a tendency to emphasize differences in community struc- ture and dominants in this study and other studies in Colorado, much similarity is seen in the floristic inventories from the various ar- eas. The greatest similarity, 74%, occurs be- tween the Ruby Range and the San Juan Mountains and a slightly lower 70% with the Indian Peaks area of the Front Range. The lowest similarity in vascular plant inventories, 66%, occurs between this study and the Mosquito Range. Phytogeography Table 1 shows the phytogeographic distri- bution of the flora. Four elements are recog- nized, each of which may be combined with more specific geographic subelements (Ko- markova 1976). Several of these subelements should be defined. The Rocky Mountains subelement includes the Northern Rocky Mountain province south to the Laramie Basin in Wyoming. The Southern Rocky Mountains subelement includes southern Wyoming, Colorado, New Mexico, and Ari- zona. The Colorado subelement represents species which are endemic to Colorado. Phy- togeographic determinations for taxa are taken from Porsild (1957), Weber (1965), Munz and Keck (1970), Komarkova (1976), Cronquist et al. (1977), Porsild and Codv (1980), and Moss (1983). As may be seen from the percentages given, the largest part of the vascular flora is made up of alpine species (35.5%) and western North Table 1. Affinities of the flora elements in the Ruby Range, Colorado. Abbreviations following each unit are cited in the annotated checklist. Percent Element Abbreviation of taxa Element Boreal montane BM 24.1 Montane M 16.8 Arctic alpine AA 23.6 Alpine A 35.5 Geocraphic subelement Circumpolar C 17.7 North American NA 12.3 Western North American WNA 32.3 Rocky Mountains RM 14.5 Southern Rocky Mountains SRM 11.8 Colorado CO 1.4 North American-Asiatic NAA 8.6 North American-European NAE 1.4 American species (32.3%). The circumpolar subelement (17.7%), which is closely identi- fied with the arctic-alpine element, is a sec- ond important component of the flora. With the exception of seven species, the North American-Asiatic subelement is linked also with the arctic-alpine element. In the mon- tane element the Rocky Mountain species are nearly double the Southern Rocky Mountain species, whereas the latter two are nearly equal in the alpine element. A stronger affin- ity between the Ruby Range alpine flora and the Asiatic alpine flora than to the European alpine flora is indicated by the higher percent- age of North American-Asiatic species (8.6%) in relation to North American-European spe- cies (1.4%). This appears to be the case in all ranges of Colorado studied floristically. A comparison of phytogeographic analyses of the Ruby Range shows a higher boreal- montane and montane representation and a concomitantly lower arctic-alpine representa- tion in this study than in the San Juan Moun- tains (Hartman and Rottman 1985). This same trend is seen in the Mosquito Range compari- son (Hartman and Rottman 1985). The west- ern North American subelement is higher, however, in the Ruby Range than in either the San Juan Mountains or Mosquito Range. There is less than 0.2% difference in the Southern Rocky Mountain species between all three mountain ranges. A comparison of the phytogeographic analyses of this study with the Indian Peaks area of the Front Range, northern Colorado Januan' 1987 Hartman, Rottman: Colorado Alpine Flor,\ 155 (Komarkova 1976), indicates a decrease in the number of arctic-alpine (5.4%) and alpine (5.0%) species. Among the subelements there is a decrease in circumpolar (8. 1%) and North American-Asiatic (2.1%) species and a small increase (3.7%) in western North American species. Colorado Endemics There are only three endemic species, Col- orado subelement, found in the Ruby Range: Draha spectahilis var. oxylobo, Poteutilla stibjiiga var. subjuga, and Senecio soIdaneUa. This number is lower than in the more northerly Mosquito Range and Indian Peaks area of the Front Range and fails to support the statement of Major and Ramberg (1967) that endemism increases in a southerly direc- tion. Annotated Checklist of Vascular Plant Species Pterophyta Selaginellaceae Selaginella densa Rydb. Common; dry and moist meadows, fellfield, dry and moist ledges, krummliolz. talus, and patterned ground. A/WNA. Adiantaceae Cnjptogramma crispa (L.) Br. ex Hook. ssp. acrosti- choides (R. Br.) Hulten. Infrequent; dry and moist mead- ows, dry ledge, and talus. BM/NAA. Aspleniaceae Athyrium destentifolium Tausch ex Opiz var. ameri- canum (Butters) Boivin. Rare; talus and disturbed area. BM/N.\A. Cystopteris fragilis (L.) Bernh. Infrequent; moist and wet meadows, and moist ledges. AA/C. CONIFEROPHYTA Pinaceae Abies lasiocarpa (Hook.) Nutt. Rare; krununbolz. BM/ WNA. Juniperus communis h. Rare; kriunmholz. BM/C. Picea engelmannii Parry ex Engelm. Rare; krunimholz. BM/WNA. AnTHOPHITA - DlCOTi LEDONEAE Apiaceae Angelica grayi Coult. & Rose. Infrequent; moist and wet meadows, shrub tundra, talus, and disturbed area. A/SRM. Ligusticum porteri Coult. & Rose. Rare; moist meadow and talus. M/RM. Oreoxis alpina (Gray) Coult. & Rose. Rare; dry meadow. A/SRM. Oreoxis bakeri Coult. & Rose. Infrequent; dry and moist meadows, dry and moist ledges, and rivulet. A/ SRM. Oxypolis fendleri (Gray) Heller. Rare; moist ledge and rivulet. M/SRM. Pseudocymopterus montaiius (Gray) Coult. & Rose. Infrequent; dry and moist meadows, fellfield, shrub tun- dra, krummholz, and disturbed area. M/SRM. Asteraceae Achillea millefolium L. var. lanulosa (Nutt.) Piper. Infrequent; dr\ and moist meadows, shrub tundra, krummholz, and talus. A/WNA. Agoseris aurantiaca (Hook.) Greene. Infrequent; moist meadow, fellfield, and krummholz. BM/WNA. Agoseris glauca (Pursh) Raf. Infrequent; dry and moist meadows, dry ledge, shrub tundra, talus, and disturbed area. BM/NA. Antennaria alpina (L.) Gaertn. Common; dry and moist meadows, fellfield, dry and moist ledges, krummholz, and talus. .\.VNAE. Antennaria microphijlla Rydb. Rare; talus and dis- turbed area. BM/NA. Arnica mollis Hook. Common; dry, moist and wet meadows, dry and moist ledges, shrub tundra, krummholz, and disturbed area. BM/NA. Arnica rijdbergii Greene. Very rare; dry meadow. BM/WNA Artemisia ludoviciana Nutt. ssp. incompta (Nutt.) Keck. Wr\ rare; dry meadow. M/WNA. Artemisia scoptdorum Gray. L^biquitous; dry and moist meadows, fellfield, dry and moist ledges, shrub tundra, krummholz, talus, rivulet, and disturbed area. .VRM. Aster foliaceus Lindl. var. apricus Gray. Infrequent; moist and wet meadows, fellfield, moist ledge, shrub tundra, and disturbed area. A/WNA. Chaenactis alpina (Gray) H. E. Jones. Infrequent; dry meadow, fellfield, and talus. M/WN.A.. Erigeron coulteri Porter. Rare; moist meadow and shrub tundra. BM/WNA. Erigeron elatior (Gray) Gray. Rare; dr>' meadow and talus. M/SRM. Erigeron melanocephalus A. Nels. Infrequent; moist and wet meadows, fellfield, moist ledge, and talus. A/ SRM. Erigeron pinnatisectus (Gray) A. Nels. Common; dry and moist meadows, fellfield, dry and moist ledges, krummholz, and talus. .VSRM. Erigeron peregrinus (Pursh) Greene. Common; dry, moist and wet meadows, dry ledge, shrub tundra, krummholz, and rivulet. BM/WNA. Erigeron simplex Greene. Common; dry and moist meadows, fellfield, drv and moist ledges, krummholz, and talus. .VWNA. Haplopappus parryi Gray. Very rare; shrub tundra. M/SRM. Haplopappus pygtnaeus (Torr. & Gray) Gray. Very rare; fellfield. A/RM. Heterotheca fulcrata (Greene) Shinners. Infrequent; dry meadow, dr>- ledge, and talus. M/RM. Hieracium gracile Hook. Infrequent; dry and moist meadows, fellfield, dr> and moist ledges, and krummholz. A/WNA. 156 Great Basin Naturalist Vol. 47, No. 1 Hymenoxys grandiflora (Torr. & Gray ex Gray) Parker. Common; dry and moist meadows, fellfield, dry and moist ledges, krummholz and disturbed area. A/RM. Senecio amplectens Gray var. amplectens. Infrequent; wet meadow, moist ledge, talus, rock debris habitats, snowbank, and disturbed area. M/RM. Senecio amplectens Gray var. holmii (Greene) Har- rington. Infrecjuent; dry meadow, fellfield, dry ledge, talus, and disturbed area. M/RM. Senecio atratus Greene. Infrequent; dry and wet meadows and krummholz. A/SRM. Senecio crassulus Gray. Ubi(juitous; dry, moist and wet meadows, moist ledge, shrub tundra, krummholz, talus, rivulet, snowbank, and disturbed area. BM/WNA. Senecio dimorphophyllus Greene. Infrequent; moist and wet meadows, dry and moist ledges, and shrub tun- dra. M/RM. Senecio soldanella Gray. Rare; fellfield. A/CO. Senecio taraxacoides (Gray) Greene. Very rare; talus. A/SRM. Senecio triangularis Hook. Rare; moist meadow and moist ledge. BM/WNA. Senecio werneriifolius (Gray) Gray. Common; dry and moist meadows, fellfield, dry ledge, talus, rivulet, and disturbed area. M/RM. Solidago spathulata DC. var. nana (Gray) Cronq. Common; dry and moist meadows, fellfield, dry ledge, shrub tundra, krummholz, and talus. A/WNA. Taraxacum ceratophorum (Ledeb.) DC. Infrequent; dry meadow, talus, and disturbed area. AA/C. Taraxacum lyratum (Ledeb.) DC. Very rare; dry ledge. AA/NAA. Boraginaceae Mertensia bakeri Greene. Infrequent; dry meadow, fellfield, dry ledge, and disturbed area. A/SRM. Mertensia ciliata (James ex Torr.) G. Don. Infrequent; moist and wet meadows, shrub tundra, krummholz, and rock debris habitats. BM/WNA. Brassicaceae Arabis drummondii Gray. Common; dry and moist meadows, fellfield, dry ledge, krummholz, talus, and disturbed area. BM/NA. Arabis lemmonii S. Wats. Very rare; talus. A/WNA. Cardamine cordifolia Gray. Infrequent; wet meadow, shrub tundra, and rivulet. BM/WNA. Draba aurea Vahl. Infrequent; fellfield, talus, and dis- turbed area. AA/C. Draba crassa Rydb. Rare; dry ledge. A/RM. Drafoa crassi/o/ta Graham. Infrequent; moist meadow, fellfield, moist ledge, talus, and disturbed area. AA/NAE. Draba fladnizensis Wulfen. Rare; fellfield and talus. AA/C. Draba incerta Payson. Rare; patterned ground and disturbed area. AA/WNA. Draba nivalis Lilj. Very rare; dry ledge. AA/C. Draba oligosperma Hook. Very rare; fellfield. AA/ WNA. Draba spectabilis Greene var. oxyloba (Greene) Gilg. ex O. E. Schulz. Infrequent; drv and moist meadows and fellfield. A/CO. Draba spectabilis Greene var. spectabilis. Rare; moist meadow and talus. M/RM. Draba streptocarpa Gray var. streptocarpa. Rare; dry ledge. A/SRM. Erysimum nivale (Greene) Rydb. Infrequent; dry meadow, felHield, dr\ ledge, and disturbed area. A/SRM. Rorippa curvipes Greene. Infrequent; moist and wet meadows and disturbed area. A/RM. Smeloivskia calycina (Steph.) C. A. Mey. ex Ledeb. Infrecjuent; dry and moist meadows, fellfield, dry ledge, krummholz, and patterned ground. AA/NAA. Thlaspi montanum L. Ubiquitous; dry, moist and wet meadows, fellfield, dry and moist ledges, shrub tundra, krummholz, talus, snowbank, and disturbed area. A/C. Campanulaceae Campanula rotundifolia L. Infrequent; dry and moist meadows, fellfield, dry ledge, and krummholz. BM/C. Campanula uniflora L. Rare; drv meadow and dry ledge. AA/C. Caryophyllaceae Arenaria congesta Nutt. ex Torr. & Gray. Infrequent; dry and moist meadows, fellfield, dry ledge, and krummholz. M/WNA. Cerastium earlei Rydb. Common; dry and moist mead- ows, fellfield, dry ledge, shrub tundra, talus, patterned ground, and disturbed area. A/RM. Minuartia biflora (L.) Schinz & Thellung. Rare; fell- field and dry ledge. AA/C. Minuartia obtusiloba (Rydb.) House. Infrequent; dry and moist meadows, fellfield, and dry and moist ledges. AA/NAA. Minuartia rubella (Wallenb.) Hiern. Infrequent; dry and moist meadows, fellfield, dry ledge, krummholz, and patterned ground. AA/C. Minuartia stricta (Sw.) Hiern. Very rare; moist ledge. AA/C. Moehringia lateriflora (L.) Fenzl. Rare; shrub tundra and krummholz. AA/C. Moehringia macrophylla (Hook.) Fenzl. Very rare; shrub tundra. BM/NA. Sagina saginoides (L.) Karst. Infrequent; moist meadow, fellfield, moist ledge, and disturbed area. AA/ C. Silene acaulis (L.) Jacq. var. subacaidis (F. N. Williams) C. L. Hitchc. & Maguire. Common; dry and moist meadows, fellfield, dry and moist ledges, krummholz, talus, patterned ground, and disturbed area. AA/NAA. Silene drummondii Hook. Rare; dry meadow and krummholz. BM/NA. Silene kingii (S. Wats.) Bocquet. Rare; moist meadow and fellfield. A/SRM. Silene uralensis (Rupr.) Bocquet. Very rare; fellfield. AA/C. Stellaria longipes Goldie. Rare; krummholz and talus. BM/NA. Stellaria umbellata Turcz. ex Kar. & Kir. Infrequent; moist and wet meadows, shrub tundra, talus, and dis- turbed area. A/NAA. Celastraceae Pachistima myrsinites (Pursh) Raf. Very rare; talus. M/WNA. January 1987 HaRTMAN. ROTTMAN: COLORADO ALPINE FlORA 157 Crassulaceae Sedunt integrifolium (Raf.) A. Nels. ex Coult. & A. Nels. Ubi(iuitou.s; dry, moist, and wet meadows, fellfield, dry and moist ledges, shrub tundra, krummholz, talus, rock debris habitats, rivulet, and disturbed area. AAJ NAA. Sedum lanceolatutn Torr. Common; dry and moist meadows, fellfield, dry ledge, krummholz, talus, and patterned ground. A/WNA. Sedum rhodanthum Gray. Infrequent; moist and wet meadows, moist ledge, and shrub tundra. A/RM. Ericaceae Arctostaphtjlos uva-ursi (L.) Spreng. Very rare; moist ledge. BM/NA. Caultheria httmifusa (Graham) Rydb. Very rare; moist ledge. BM/WNA. Vaccinium caespitosiim Michx. Common; dry and moist meadows, fellfield, dry and moist ledges, shrub tundra, and krummholz. BM/NA. Vaccinium myrtillus L. ssp. oreophilum (Rydb.) Love, Love & Kapoor. Very rare; shrub tundra. BM/C. Fabaceae Lupinus argenteus Pursh. Infrequent; dry meadow, dry ledge, shrub tundra, and talus. M/WNA. Trifolium dasyphyllum Torr. & Gray. Infrequent; dry meadow, fellfield, dry ledge, krummholz, and talus. A/ KM, Trifolium nanum Torr. Infrequent; dry meadow, fell- field, dry ledge, and patterned ground. A/RM. Trifolium parryi Gray. Ubiquitous; dry, moist, and wet meadows, dry and moist ledges, shrub tundra, krummholz, talus, snowbank, and disturbed area. A/RM. Gentianaceae Gentiana algida Pallas. Infrequent; dry and moist meadows, fellfield, and shrub tundra. AA/NAA. Gentiana calycosa Griseb. Rare; moist meadow and krummholz. A/VVNA. Gentiana prostrata Haenke ex Jacq. Very rare; moist ledge. AA/NAA. Gentianella amarella (L.) Rorner. Infrequent; dry and moist meadows, fellfield, dry ledge, and shrub tundra. BM/C. Gentianella tenella (Rottb.) Rorner. Infrequent; dry and moist meadows, and moist ledge. AA/C. Centianopsis barbellata (Engelm.) litis. Very rare; krummholz. A/SRM. Gentianopsis thermalis (Kuntze) litis. Infrequent; dry, moist, and wet meadows, and moist ledge. A/RM. Swertia perennis L. Rare; moist meadow and shrub tundra. A/C. Geraniaceae Geranium richardsonii Fisch. & Trautv. Rare; dry ledge and krummholz. M/WNA. Hydrophyllaceae Phacelia heterophylla Pursh. Rare; fellfield and talus. M/WNA. Phacelia sericea (Graham) Gray. Infrequent; dry meadow, krummholz, talus, and disturbed area. A/WNA. Onagraceae Epilobiutn anagallidifolium Lam. Infrequent; moist and wet meadows, talus, rivulet, and disturbed area. AA/C. Orobanchaceae Orobanche uniflora L. Very rare; moist meadow. BM/ NA. Papaveraceae Corydalis caseana Gray ssp. brandegii{S. Wats.)G. B. Ownbey. Common; moist and wet meadows, moist ledge, shrub tundra, krummholz, talus, rivulet, snow- bank, and disturbed area. M/SRM. Polemoniaceae Polemonium delicatum Rydb. Very rare; krummholz. M/SRM. Polemonium viscosum Nutt. Infrequent; dry and moist meadows, talus, and disturbed area. A/WNA. Polygonaceae Eriogonum jamesii Benth. var. xanthum (Small) Re- veal. Very rare; talus. A/WNA. Eriogonum umbellatum Torr. Infrequent; dry meadow, fellfield, dry ledge, and talus. M/WNA. Oxyria digyna Hill. Common; moist meadow, fellfield, dry ledge, talus, rock debris habitats, rivulet, and dis- turbed area. AA/C. Polygonum bistortoides Pursh. Ubicjuitous;dry, moist, and wet meadows, fellfield, dry and moist ledges, shrub tundra, krummholz, talus, patterned ground, rivulet, and disturbed area. A/WNA. Polygonum douglasii Greene. Very rare; dry meadow. BM/NA. Polygonum viviparum L. Infrequent; dry and moist meadows, dry and moist ledges, shrub tundra, and rock crevice. AA/C. Portulacaceae Claytonia lanceolata Pursh. Very rare; talus. M/WNA. Claytonia megarhiza (Gray) Parry ex S. Wats. Infre- quent; fellfield, dry ledge, talus, patterned ground, and rock debris habitats. A/RM. Lewisia pygmaea (Gray) B. L. Robins. Common; dry, moist, and wet meadows, fellfield, moist ledge, shrub tundra, talus, and rivulet. A/WNA. Primulaceae Androsace septentrionalis L. Infrequent; dry and moist meadows, fellfield, talus, and patterned ground. AA/C. Primula parryi Gray. Infrequent; moist and wet mead- ows, moist ledge, talus, and rivulet. A/RM. Ranunculaceae Anemone narcissiflora L. ssp. zephyra (A. Nels.) Love, Love & Kapoor. Common; dry, moist, and wet meadows, fellfield, moist ledge, krummholz, and shrub tundra. A/ SRM. Aquilegia coerulea James. Infrequent; dry meadow, fellfield, dry ledge, shrub tundra, krummholz, and talus. M/RM. 158 Great Basin Naturalist Vol. 47, No. 1 Caltha leptosepala DC. InfVe(}iient; moist and wet meadows, moist ledge, shrub tundra, and rivulet. A/ wna. Delphinium barbetji (Huth) Huth. Very rare; talus. M/SRM. Ranunculus alisamifolius Geyer ex Benth. var. mon- tanus S. Wats. Infrequent; moist and wet meadows, moist ledge, shrub tundra, and rivulet. BM/WNA. Ranunculus eschscholtzii Schlect. Infrecjuent; moist and wet meadows and moist ledge. AA/NAA. Ranunculus macauleyi Gray. Common; moist and wet meadows, moist ledge, talus, rivulet, snowbank, and dis- turbed area. A/SRM. Trollius laxus Salisb. ssp. albiflorus (Gray) Love, Love & Kapoor. Infrequent; moist and wet meadows, and shrub tundra. BM/WNA. Rosaceae Fragaria vesca L. ssp. arnericana (Porter) Staudt. Rare; moist meadow and krummholz. BM/NA. Geum rossii (R. Br.) Ser. var. turhinatum (Rydb.) C. L. Hitchc. Ubiquitous; dr\', moist, and wet meadows, fellfield, dry and moist ledges, shrub tundra, krummholz, talus, patterned ground, rivulet, snowbank, and dis- turbed area. AA/NAA. Ivesia gordonii (Hook.) Torr. & Gray. Common; dry and moist meadows, fellfield, dry and moist ledges, krummholz, talus, and disturbed area. M/WNA. Potentilhi diversifolia Lehni. Ubitiuitous; dry, moist, and wet meadows, fellfield, dry and moist ledges, shrub tundra, krummholz, talus, patterned ground, rivulet, snowbank, and disturbed area. A/WNA. Potentilhi fruticosa L. ssp. floribunda (Pursh) Elking- ton. Infrequent; dry and moist meadows, fellfield, dry ledge, and talus. BM/C. Potentilla nivea L. Infrequent; dry meadow, fellfield, dry ledge, and patterned ground. AA/C. Potentilla ovina Macoun. Infrecjuent; fellfield, dry and moist ledges. M/WNA. Potentilla rubricaulis Lehm. Rare; drv meadow and fellfield. AA/NA. Potentilla subjuga Rydb. var. subjuga. Rare; dry meadow and dry ledge. A/CO. Rubus idaeus L. ssp. sachalinensis (Levi.) Focke. Very rare; talus. BM/NAA. Sibbaldia procumbens L. Ubicjuitous; dry, moist, and wet meadows, fellfield, dry and moist ledges, shrub tun- dra, krummholz, talus, rivulet, and disturbed area. AA/C. Salicaceae Salix arctica Pallas. Infrequent; dry and moist mead- ows and patterned ground. A/WNA. Salix brachycarpa Nutt. Infrequent; moist ledge, shrub tundra, and krummholz. BM/NA. Salix glauca L. var. villosa (Hook.) Anderss. Rare; shrub tundra and krummholz. BM/WNA. Salix planifolia Pursh. Rare; moist ledge and shrub tundra. BM/NA. Salix reticulata L. ssp. nivalis (Hook.) Love, Love & Kapoor. Infrequent; dry and moist meadows, fellfield, dry ledge, and shrub tundra. A/WNA. Sa,xifragaceae Heuchera parvifolia Nutt. ex Torr. & Gray. Rare; moist meadow and dry ledge. M/RM. Ribes coloradense Coville. Verv rare; drv ledge. M/ SRM. Ribes montigenum McClatchie. Verv rare; krumm- holz. BM/WNA. Saxifraga adscendens L. ssp. oregonensis (Raf.) Bacig. Very rare; moist meadow. AA/NAE. Saxifraga bronchialis L. ssp. austromontana (Wieg.) Piper. Infrecjuent; fellfield, dry ledge, krummholz, talus, and patterned ground. A/WNA. Saxifraga caespitosa L. ssp. delicatula (Small) Porsild. \'ery rare; patterned ground. AA/C. Saxifraga chrysantha Gray. Very rare; patterned ground. AA/NAA. Saxifraga debilis Engelm. ex Gray. Infrequent; moist meadow, fellfield, dry and moist ledges, and talus. A/RM. Saxifraga flagellar is Sternb. & Willd. ssp. platysepala (Trautv.) Porsild. Rare; fellfield and patterned ground. A/SRM. Saxifraga odontoloma Piper. Rare; wet meadow and moist ledge. BM/WNA. Saxifraga oregana T. J. Howell ssp. montanensis (Small) C. L. Hitchc. Infrequent; moist and wet meadows and shrub tundra. M/WNA. Saxifraga rhomboidea Greene. Common; dry and moist meadows, fellfield, dry and moist ledges, shrub tundra, krummholz, talus, and rivulet. A/WNA. Scrophulariaceae Resseya alpina (Gray) Rydb. Infrequent; dry and moist meadows, fellfield, dry ledge, talus, and patterned ground. A/SRM. Castilleja occidentalis Torr. Ubiquitous; dry, moist, and wet meadows, fellfield, dry and moist ledges, shrub tundra, krvunmholz, talus, and disturbed area. A/RM. Castilleja rhexifolia Rydb. Infrequent; moist meadow, shrub tundra, and ri\ ulet. BM/WNA. Mimulus guttatus DC. Rare; moist ledge and disturbed area. BM/NA. Pedicularis bracteosa Benth. var. paysoniana (Pen- nell) Cronq. Rare; moist meadow and shrub tundra. M/ RM. Pedicidaris groeidandica Retz. Infrequent; moist and wet meadows, moist ledge, shrub tundra, and rivulet. AA/NA. Pedicularis parryi Gray. Infrequent; dry and moist meadows, fellfield, drv and moist ledges, and shrub tun- dra. A/RM. Penstemon whippleanus Gray. Common; dry and moist meadows, fellfield, dry and moist ledges, shrub tundra, krummholz, and talus. M/RM. Veronica wormskjoldii Roemer & Shultes. Common; dry, moist, and wet meadows, dry and moist ledges, shrub tundra, krununholz, rivulet, and disturbed area. AA/NA. Valerianaceae Valeriana capitata Pallas ex Link. Very rare; fellfield. AA/NAA. Valeriana edulis Nutt. ex Torr. & Gray. Rare; moist meadow and dry ledge. BM/WNA. Violaceae Viola adunca Sm. ssp. bellidifolia (Greene) Harring- ton. Infrequent; moist meadow, fellfield, and moist ledge. BM/NA. January 1987 HARTMAN, ROTTMAN: COLORADO ALPINE FlORA 159 Viola nuttallii Pursh. Rare; dr\ meadow and dry ledge. M/VVNA. ANTHOPH^TA - MONOCOTYLEDONEAE Cyperaceae Carex albonigra Mackenzie. Infrequent; moist meadow, moist ledge, shrub tundra, and talus. AA/WNA. Carex aquatilis Wahlenb. Rare; wet meadow. AA/C. Carex arapahoensis Clokey. Rare; dry meadow and rock debris habitats. A/SRM. Carex brevipes VV. Boott. Very rare; moist meadow. BM/NA. Carex brunnescens (Pers.) Poir. Very rare; wet meadow. BM/C. Carex ebenea Rydb. Common; dry, moist, and wet meadows, fellfield, moist ledge, shrub tundra, talus, and disturbed area. .VRM. Carex elynoides Holm. Rare; fellfield. A/WNA. Carex foenea Willd. Infrequent; dry ledge, krumm- holz, and talus. BM/NA. Carex geyeri Boott. Very rare; krummholz. M/WNA. Carex haydeniana OIney. Infrequent; dry and moist meadows, dry ledge, talus, and disturbed area. A/WNA. Carex heteroneura W. Boott var. chalciolepis (Holm) F. J. Herm. Common; dry, moist, and wet meadows, fellfield, dry and moist ledges, shrub tundra, talus, and disturbed area. A/WNA. Carex heteroiieura W. Boott var. epapillosa (Macken- zie) F. J. Herm. Very rare; dry meadow. M/WNA. Carex illota Bailey. Rare; moist and wet meadows. A/WNA. Carex nelsonii Mackenzie. Rare; fellfield and dry ledge. A/SRM. Carex nigricans C. A. Mey. Infrequent; moist and wet meadows, moist ledge, shrub tundra, and rivulet. A/ NAA. Carex nova Bailey. Infrequent; moist meadow, moist ledge, shrub tundra, and rivulet. BM/WNA. Carex phaeocephala Piper. Common; dry and moist meadows, fellfield, dry and moist ledges, krummholz, talus, rock debris habitats, and disturbed area. A/WNA. Carex praeceptorum Mackenzie. Very rare; wet meadow. A/WNA. Carex pseudoscirpoidea Rydb. Very rare; shrub tun- dra. A/WNA. Carex pyrenaica Wallenb. Infrequent; moist meadow, fellfield, and talus. A/C. Carex scopulorum Holm. Very rare; moist meadow. A/WNA, Eleocharis acicularis (L. ) Roemer & Schultes. Very rare; wet meadow. A.VC. Kobresia myositroides (Vill.) Fiori & Paol. Rare; dry meadow and dry ledge. AA/C. Juncaceae Juncus drummondii E. Mey. Ubiquitous; dry, moist, and wet meadows, fellfield, dry and moist ledges, shrub tundra, krummholz, talus, rivulet, and disturbed area. A/WNA. Juncus mertensianus Bong. Infrequent; moist and wet meadows, moist ledge, shrub tundra, rivulet, and dis- turbed area. A/NAA. Juncus tracyi Rydb. Verv rare; disturbed area. M/ WNA. Ltizula spicata (L.) DC. Ubi(}uitous; dry and moist meadows, ielHield, dry and moist ledges, shrub tundra, talus, patterned ground, and disturbed area. A/RM. Liliaceae Erythronium grandiflorum Pursh var. chrysandrurn (Applegate) Scroggan. Common; dry, moist, and wet meadows, fellheld, dry and moist ledges, shrub tundra, talus, and rivulet. M/RM. Lloydia serotina (L.) Salisb. ex Reichenb. Rare; dry meadow and dr\' ledge. AA/C. Zigadenus elegans Pursh. Infrequent; dry and moist meadows, dry and moist ledges, shrub tundra, and rivulet. AA/NA. Poaceae Agropyron scribneri Vasey. Infrequent; dry meadow, fellfield, dry ledge, krummholz, talus, and disturbed area. A/WNA. Agropyroti trachycatdum (Link) Malte ex H. F. Lewis var. latiglume (Scribn. & Smith) Beetle. Common; dry and moist meadows, fellfield, shrub tundra, talus, rock debris habitats, and disturbed area. AA/NA. Agrostis scabra Willd. Verv rare; dry meadow. BM/ NA. Calwtuigrostis purpurascens R. Br. Infrequent; dry and moist meadows, fellfield, dry ledge, and krummholz. AA/NAA. Danthonia intermedia Vasey. Infrequent; dry meadow, fellheld, and dry ledge. BM/NAA. Deschampsia caespitosa (L.) Beauv. Ubiquitous; dry, moist, and wet meadows, fellfield, dry and moist ledges, shrub tundra, talus, rock debris habitats, rivulet, and disturbed area. BM/C. Elymus glaucus Buckl. Very rare; krummholz. BM/ NA. Festuca brachyphylla Schultes. Ubiquitous; dry and moist meadows, fellfield, dry and moist ledges, kriniim- holz, talus, patterned ground, rock debris habitats, and disturbed area. AA/C. Festuca ovina L. Very rare; moist meadow. AA/C. Phleum alpinum L. Common; dry, moist, and wet meadows, fellfield, dry and moist ledges, shrub tundra, krummholz, and disturbed area. AA/C. Poa alpina L. Ubiquitous; dry, moist, and wet mead- ows, fellfield, dry and moist ledges, shrub tundra, krummholz, talus, rock debris habitats, snowbank, and disturbed area. AA/C. Poa arciica R. Br. Rare; moist meadow and fellfield. A/RM. Poa epilis Scribn. Infrequent; dry and moist meadows, dry ledge, shrub tundra, and krinnmholz. BM/WNA. Poa fendleriana (Steud.) Vasey. Infrequent; dr> and moist meadows, krummholz, and disturbed area. BM/ NA. Poa leptocoma Trin. Infrequent; moist meadow, dry ledge, and disturbed area. A/WNA. Poa rupicola Nash ex Rydb. Common; dry and moist meadows, fellfield, dry ledge, krummholz, patterned ground, and rock debris habitats. A/WNA. Poa sandbergii Vasey. Very rare; dry meadow. BM/ NA. Stipa lettermanii Vasey. Very rare; dry meadow. M/ RM. 160 Great Basin Naturalist Vol. 47, No. 1 Trisetum spicatum (L.) Richter. Ubicjuitoiis; dry, moist, and wet meadows, fellfield, dry and moist ledges, shrub tundra, krummholz, talus, patterned ground, rock debris habitats, and disturbed area. AA/C. Literature Cited Bathke. D. M. 1968. The flora of the subalpine and alpine zones in Robinson Basin, Colorado. Unpublished thesis, Western State College, Gunnison, Colo- rado. 92 pp. Cox, C. F. 193.3. Alpine plant succession on James Peak, Colorado. Ecol. Monog. 3: 299-372. Cronquist, a., a. Holmgren, N H Holmgren. J L Re- veal, AND P. K Holmgren 1977. Intermountain flora. Vol. 6. Columbia University Press, New York. 584 pp. Eddleman, L. F., and R. T. Ward 1984. Phytoedaphic relationships in alpine tundra, north-central Colo- rado, U.S.A. Arctic and Alpine Research 16: 343-359. Gaskill, D L , L H. Godwin, and F E. Mutschler 1967. Geologic map of the Oh-Be-Joyful quadran- gle, Gunnison County, Colorado. USGS, Wash- ington, D.C. Hartman, E. L.. and M L. Rottman 1985a. The alpine vascular flora of the Mt. Bross massif Mosquito Range, Colorado. Phytologia 57: 133-151. 1985b. The alpine vascular flora of three cirque basins in the San Juan Mountains, Colorado. Madroiio 32: 253-272. Kartesz, J. T., and R. Kartesz. 1980. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. Vol. II. The biota of North America. University of North Carolina Press, Chapel Hill. 498 pp. Ko.viarkova. v. 1976. Alpine vegetation of the Indian Peaks area, Colorado Rocky Mountains. Unpub- lished dissertation. University of Colorado, Boul- der. 655 pp. Langenheim, J. H. 1962. Vegetation and environmental patterns in the Crested Butte area, Gunnison County, Colorado. Ecol. Monog. 32: 249-285. Major, J , andS A Bamberg 1967. A comparison of some North American and Eurasian alpine ecosvstems. Pages 89-118 in H. E. Wright, Jr., and'w. H. Osburn, eds., Arctic and alpine environments. Indiana University Press, Bloomington. Marr, J W 1961. Ecosystems of the east slope of the Front Range in Colorado. University of Colorado Studies, Series in Biology 8: 1-134. Moss, E. H. 1983. Flora of Alberta: a manual of flowering plants, ferns, and fern allies found growing with- out cultivation in the province of Alberta, Canada. University of Toronto Press, Toronto. 687 pp. MuNZ, P. A., and D D. Keck 1970. A California flora. University of California Press, Berkeley. 1,681pp. Porsild, a E 1957. Illustrated flora of the Canadian Arctic Archipelago. Nat. Mus. of Canada Bull. 146. Biological Series 50. 209 pp. Porsild, A E , and W J. Cody 1980. Vascular plants of continental Northwest Territories, Canada. Nat. Mus. of Nat. Sci., Ottawa. 667 pp. Pr.\ther. T 1982. Geology of the Gunnison country. B& B Printers, Gunnison, Colorado. 149 pp. ScHAACK, C. G. 1983. The alpine vascular flora of Arizona. Madroiio 30: 79-88. Soil Conservation Service. 1979. Plants of Custer County (checklist). Westcliffie, Colorado. 70 pp. Weber. W A. 1965. Plant geography in the Southern Rocky Mountains. Pages 453-468 in H. E. Wright and D. G. Frey, eds., The Quaternary of the United States. Princeton University Press, Princeton. DOUGLAS-FIR DWARF MISTLETOE PARASITIZING PACIFIC SILVER FIR IN NORTHERN CALIFORNIA Robert L. Mathiasen' and Larry Loltis' Abstract. — Douglas-fir dwarf mistletoe {Arceuthobium doug,lasii) was found parasitizing Pacific silver fir (Abies amabilis) in northern Siskiyou County, California. This is the first report of Douglas-fir dwarf mistletoe on this host. Approximately 40% of the Pacific silver firs near heavily infected Douglas-firs were infected. The low level of infection on Pacific silver fir, unusually large swellings at the points of infection, and poor shoot production on infected branches indicate some degree of host-parasite incompatibility. Douglas-fir dwarf mistletoe {Arceuthobium douglosii Engelm.) is a damaging parasite of Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) in the western United States (Graham 1961, Hawksworth and Wiens 1972). Dou- glas-fir dwarf mistletoe has been reported to occasionally or rarely parasitize true firs (Abies spp.), including grand fir {Abies gran- dis [Dougl.] Lindl.), corkbark fir (A. lasio- carpa var. arizonica [Merriam] Lemm.), sub- alpine fir (A. lasiocarpa var. lasiocarpa [Hook.] Nutt.), and white fir (A. concolor [Gord & Glend.] Lindl.) (Hawksworth and Wiens 1972, Mathiasen 1984, Mathiasen and Hawksworth 1983). This is the first report of Douglas-fir dwarf mistletoe on Pacific silver fir (A. amabilis [Dougl.] Forbes). Pacific silver fir is a common tree in the Olympic and Cascade mountains of the Pacific Northwest. However, south of Crater Lake, Oregon, it occurs only in isolated populations in Siskiyou County, California (Griffin and Critchfield 1976). We discovered Douglas-fir dwarf mistletoe parasiting Pacific silver fir in one of these populations, approximately 0.5 mile N of White Mountain (T18N, R3W, SSI). The infestation of Douglas-fir dwarf mistletoe on Pacific silver fir was about five acres in size at an elevation between 1,580 and 1,700 m (5,200 and 5,600 ft). The infected Pacific silver firs were in a stand primarily composed of Douglas-fir, white fir, Shasta red fir {Abies magnifica var. shastensis Lemm.), and western white pine {Pinus monticola Dougl.). Infected Pacific sil- ver firs were in the vicinity of large Douglas- firs heavily infected with Douglas-fir dwarf mistletoe. Two other dwarf mistletoes were also present in the stand. Sugar pine dwarf mistletoe {Arceuthobium californicum Hawksw. & Wiens) was parasitizing western white pine, and red fir dwarf mistletoe (A. abietinum f sp. magnificae Hawksw. & Wiens) was parasitizing Shasta red fir. Confir- mation that the mistletoe on Pacific silver fir was Douglas-fir dwarf mistletoe was made by examination of the aerial shoots produced on infected Pacific silver firs. Although only a few shoots were found on infected Pacific silver fir branches, they could be identified as those of Douglas-fir dwarf mistletoe. The shoots of Douglas-fir mistletoe can be distinguished from those of sugar pine dwarf mistletoe and red fir dwarf mistletoe by their small size (Hawksworth and Wiens 1972). Specimens of Douglas-fir dwarf mistletoe on Pacific silver fir have been deposited at the U.S. Forest Service Forest Pathology Herbarium, Rocky Mountain Forest and Range Experiment Sta- tion, Fort Collins, Colorado. Hawksworth and Wiens (1972) devised a 5-class host susceptibility system based on the percentage of infection of potential hosts within 20 feet of heavily infected principal hosts of a dwarf mistletoe. Their system in- cluded the following susceptibility classes: Principal (90-100% infection), Secondary (50-89% infection). Occasional (5-49% infec- tion). Rare (more than 0%, but less than 5% infection), and Immune (no infection). To as- Northern .\rizona University. School of Forestn.', Flagstaff, Arizona 86011. "USDA Forest Service, Applegate Ranger District, Rogue River National Forest, Jacksonville, Oregon 975.30. 161 162 Great Basin Naturalist Vol. 47, No. 1 certain the susceptibility class of Pacific silver fir to Douglas-fir dwarf mistletoe, we placed circular plots (radius 25 ft) around two large, heavily infected Douglas-firs. Trees within each plot were examined for dwarf mistletoe and the following data recorded for each tree: species, diameter breast height (nearest 2.0 in), and dwarf mistletoe rating (Hawksworth 1977). A total of 46 Pacific silver firs were examined in the two plots and 18 (39%) were infected. This level of infection indicates that Pacific silver fir should be classified as an occa- sional host for Douglas-fir dwarf mistletoe based on the susceptibility system of Hawksworth and Wiens. The 18 infected trees were distributed bv infection class as follows: Class 1 (10), Class 2 (3), Class 3 (2), Class 4 (2), Class 5 (1). Most of the infected Pacific silver firs (72%) had light levels of in- fection (dwarf mistletoe ratings of 1 or 2). In addition, the presence of unusually large swellings at infection points and poor produc- tion of aerial shoots on infected branches indi- cate a somewhat incompatible host-parasite relationship between Pacific silver fir and Douglas-fir dwarf mistletoe (Hawksworth and Wiens 1972). Although Pacific silver fir is an occasional host of Douglas-fir dwarf mistletoe in northern California, this host-parasite com- bination is probably not common because Douglas-fir dwarf mistletoe does not frequently occur within the geographic range of Pacific sil- ver fir (Hawksworth and Wiens 1972). Acknowledgments We thank Dave Russell for his assistance with the collection of infection data and mistletoe specimens. Literature Cited Graham, D. P. 196L Dwarf mistletoe of Douglas-fir. USDA Forest Service, Forest Pest Leaflet .54. 4 pp. Griffin. J R.. and W B Critchfield 1976. The distri- bution of forest trees in California. L^SDA Forest Service, Res. Pap. PSW-82. 118 pp. Hawksworth, F G 1977. The 6-class dwarf mistletoe rating system. USDA Forest Sei"vice, Gen. Tech. Kept. RM-48. 7 pp. Hawksworth, F. G., and D Wiens 1972. Biology and classification of dwarf mistletoes {Arceutliobitim ). USDA Agric. Handb. 401. 234 pp. Mathiasen, R L 1984. Comparative susceptibility of corkbark fir and Douglas-fir to Douglas-fir dwarf mistletoe. For. Sci. 30; 842-847. Mathiasen, R. L . and F. G. Hawksworth. 1983. Dwarf mistletoes on true firs in the Southwest. Northern Arizona Lhiiversity School of Forestry, Arizona Forestry Notes 18. 12 pp. A DISJUNCT PONDEROSA PINE STAND IN SOUTHEASTERN OREGON' Artliiir McKee" and Donald Knntson' Abstract. — An isolated stand of ponderosa pine {Pinus ponderosa) is surviving on an extremely harsh site in southeastern Oregon. Seed produetion is low because of insects, primarily pine coneworm (Dionjctria auranticella), feeding in developing cones. Seedling establishment is infrequent and dilficult because of drought and coarse, rocky soils. A rock-mulch soil surface probably reduces interspecific competition. Because stand size is small (< 2 ha, 57 individuals in 1977) and genetic variability is therefore limited, individual differences in diameter growth are probably due to microsite differences. Mycorrhizae, which could aid tree survival, were absent from a small sample of surface roots. Although the stand was enlarging in 1977, the site is sufficiently severe that local extinction is a possibility. Isolated populations of a species are of in- terest to biologists because such populations frequently represent unique genotypes adapted to particular habitats. In September 1975 and March 1977, we visited a disjunct stand of ponderosa pine {Pinus ponderosa) previously reported by Packard (1970). The isolation of the stand, 105 km from the nearest ponderosa pine (Fig. 1), and the reported old age ( ± 300 years) of a few of its trees (Packard 1970) suggest the possibility of novel ecologi- cal relationships or adaptations for extreme drought. In this paper, we describe the status of the stand in 1977, discuss its development, and report changes in diameter growth rates over the past two centuries. Site and Stand Description The disjunct stand, located in Malheur Countv, Oregon, 14.5 km WSW of Rockville (T26S,' R45E, Sec. 30, Wl/2), occurs on a steep, bare ridge of rhyolitic tuff at approxi- mately 1,450 m elevation. The ponderosa pine are growing along the crest of the ridge Fig. 1. Distribution of ponderosa pine (shaded area) in the Pacific Northwest. Arrow shows location of the dis- junct pine stand (adapted from Little 1971). Fig. 2. Site overview showing the ridge-top position of the disjunct stand, the rocky mulch nature of the soil surface, and the absence of litter. Tree farthest left is the oldest (as of 1977: 415 years, 14.5 m tall, 75.5 cm dbh). Paper 1441. Forest Research Laboratory, College of Forestry, Oregon State University, Cor\allis. Oregon 97.3.31 "Department of Forest Science, Oregon State University, Corvallis, Oregon 97331. ■'trees, Bo.x 14666, Minneapolis, Minnesota .5.5414; v\hen this work was done. Forestry Sciences Laboratory, Pacific Northwest Forest and Range Experiment Station, Corvallis, Oregon 97331. 163 164 Great Basin Naturalist Vol. 47, No. 1 Table 1. Soil characteristics of the disjunct ponderosa pine stand compared with those of other sites dominated by sagebrush (Artemisia spp.) stands in eastern Oregon. Other SI ites'' Dis pine iunct stand' 1 2 3 4 County Malheur Malheiu- Malheur Baker Union Township, range, section 26S,45E,.30 17S,43E,12 14S,39E,28 6S,39E,2 8S,41E,I8 Soil depth (cm) 0-5 5-15 0-15 0-15 0-15 0-15 Soil pH 6.01 5.65 7.7 7.6 7.6 7.6 Organic matter (%) 0.44 0.42 0.8 1.2 1.2 1.5 Cation exchange capacity (meq/100 g soil) 8.7 7.7 23.8 24.5 34.1 ,36.7 Extractable cations (meq/100 g soil) Calcium 4.9 4.6 15.2 18.0 26.2 29.0 Magnesium 2.1 2.1 5.9 6.4 11.4 12.9 Sodium 0.06 0.06 1.9 1.3 8.2 6.8 Potassium 0.17 0.11 2.2 1.2 1.4 1.6 Kjeldahl nitrogen (%) 0.0.33 0.027 0.07 0.1 0.05 0.07 Total phosphorus (ppm) 11.0 18.0 10.6 8.5 10.6 5.6 ''Soil values for the disjunct stand are means ot three samples. Courtesy Oregon State University Soil Characterization Laboratory, Corvallis. and on the upper portions of the steep north- east and southwest slopes (Fig. 2). The soil surface is covered by a loose, rocky mulch. Soil 0-15 cm deep is slightly acid (mean pH 5.8) with very low carbon content (0.44%) and cation exchange capacity (8.2 meq/100 g soil) (Table 1). Levels of calcium, magnesium, sodium, and potassium are also low, more comparable to levels in humid than semiarid cold, temperate regions (Brady 1974). Al- though nitrogen levels are low (0.03%), the carbon mitrogen ratio (15:1) is comparable to that in agricultural soils. Few plants other than ponderosa pine are growing on the site (Fig. 2). Shrub cover is especially sparse com- pared with that of the surrounding area, which is dominated by big sagebrush {Artemisia tridentata) and low sagebrush (A. arbuscula) with widely scattered juniper (Ju- niperus occidentalis). The entire stand covered < 2 ha and con- tained 57 individuals in 1977. Forty-nine trees were < 25 years old (Table 2). Several seedlings appeared to be < 5 years old, as determined by number of branch whorls and terminal bud scars; five trees were between 26 and 100 years old; and three trees were over 100 years old, the two oldest of which had 415 and 232 annual growth rings at stump height. The largest individual was 75.5 cm in diameter at breast height (dbh) and 14.5 m tall, and only two others were over 40 cm dbh and 9 m tall. Taxonomic Characteristics More than 50 needle fascicles from each of 10 trees were examined, and only three- needled fascicles were found. Needles aver- aged 20 cm long (range: 18-21 cm), which is midrange for ponderosa pine (Mirov 1967); they were dark green and generally appeared to be healthy. Both mature and immature cones were examined from several trees. Ma- ture cones were quite short, averaging 8. 1 cm long (range 6-10 cm); immature first-year cones averaged 5.5 cm long. Slightly recurved prickles, rather than the more common straight prickles, were observed, a trait often found on ponderosa pine cones in eastern Or- egon. Discussion The site clearly is harsh for ponderosa pine, as evidenced by short stature and slow growth of the older trees. Flat-topped crowns show multiple leaders, with none achieving apical dominance (Fig. 2). Seedling establishment has been infre- quent and episodic. Five trees became estab- lished near the turn of this century, about 30 trees in the early 1950s, and about 10 trees in the early 1970s. These periods of establish- ment also were periods of relatively fast di- ameter growth for the two largest trees (Fig. 3), probably indicating a more favorable cli- January 1987 McKee, Knutson: Disjunct Ponderosa Pine 165 Tahi.k 2. Number of individuals, hy dianu-tfr, luM^lit, and age classes, in the disjunct ponderosa pine stand. Diameter 0-10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 Height (m) 0.5 0.6-1.5 1.6-3.0 3.1-4.5 4.6-6.0 6.1-7.5 7.6-9.0 9.0 + < 25 \ears old 26-100 vears old 32 12 101 + vears old ^O 25 - ITREE 1 P _ 24 mmmi ITREE 3 1 ■ 22 1 \ 20 1 - E 18 ^ 1 1 _ E 1 1 T '6 - 1 r 1 K -, -| -j T1 - t- 1 ■ 1 '^ q: - 1 - 1 ; ^ - o 12 - 1 1 - cr ^ 10 - -1 1 - : - LU s 1 8 - - 6 4 2 - L •; ^ ■ i I. :- 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 YEARS BEFORE PRESENT Fig. 3. Patterns of diameter growth, per decade, of the two oldest trees in the disjunct stand (as of 197 years; tree #3, 232 years). 7; tree #1,415 mate. For most of the past 200 years, how- ever, diameter growth has been very slow, with the slowest periods 50 and 110 years ago. The droughty eonditions that restrain diame- ter growth would likely restrict seed germina- tion and establishment of young seedlings as well. Seedbed conditions also influence estab- lishment. The rocky mulch covering the steep slopes is unstable enough to be moved by frost, wind, and animals; such movement would tend to bury those seedlings managing to get a taproot into the soil. Perhaps more important, the rocky mulch may also reduce interspecific competition by preventing inva- sion of the site by other plant species. Pon- derosa pine has, by far, the largest seeds of any of the local species. A large seed with 166 Great Basin Naturalist Vol. 47, No. 1 10 15 20 25 YEARS AFTER ESTABLISHMENT 30 35 Fig. 4. Cumulative diameter grovvtli oi 10 of the largest trees in the disjunct stand (tree number is shown on the line, number of growth rings at stump height in parentheses). substantial energy reserves may be just what is needed to germinate and rise through the rock mulch. This stand may, in fact, owe its existence to the presence of the rocky mulch despite the difficulties it presents for seedling establishment. In addition to the harsh climate, insects feeding on seeds seem an important factor regulating establishment. In fall 1975, 15 trees had mature cones, and all were damaged by the pine coneworm {Dioryctria auranti- cella) probably surviving in nearby juniper trees; immature cones were similarly dam- aged. The same degree of insect damage was observed in spring 1977. If this degree of an- nual seed predation is typical, then very few sound seeds are available for germination in any given year. This same insect also attacks twigs and shoots (Furniss and Carolin 1977) and might account for the multiple leaders observed in the older trees. Despite the presence of a fire scar at the base of the oldest tree, fire probably has not been a major factor in stand development be- cause of the lack of on-site fuel (Fig. 2). We have no explanation for the origin of the stand; perhaps the seeds were carried by Indi- ans or were dispersed by animals. It may be a January 1987 McKee, Knutson: Disjunct Ponderosa Pine 167 remnant of ponderosa pine stands existing in the area thousands of years ago when the ch- mate was more favorable. We have no evi- dence that this is, in fact, a rehct stand. There is also no evidence — such as standing dead or downed trees — that the stand has been more extensive in the last century or two. At one time, the population may have consisted of two or perhaps even one individual. Once a tree was established, the general trend was for slow and relatively linear diameter growth during the first three decades (Fig. 4). The data show that variation is as great within a cohort as between. Cumulative diameter growth of trees 4, 5, and 6, all in the same cohort, shows a wide range, which could be due to genetic or microsite differences. Lim- ited cross-pollination in this very small popu- lation would have greatly reduced genetic variability; therefore, variations in growth are probably the result of variations in microsite conditions. Particular mycorrhizal fungi can enhance the survival of their coniferous symbionts. Cenococcum gcophilum and PisoUthus tincto- rius both form mycorrhizal associations on droughty sites (Trappe 1977). However, no mycorrhizae were found in small roots near the soil surface nor were any mushrooms present in the area. Because ponderosa pine has a deep taproot, extensive excavation would be necessary to thoroughly evaluate the presence and identity of mycorrhizal fungi. The survival of this stand is uncertain. The large number of seedlings relative to the num- ber of mature trees indicates a new period of stand enlargement. The site is sufficiently harsh, however, and the population so small as to make local extinction a serious possibility. Acknowledgments We thank Carol Perry and the editorial staff at the Forest Research Laboratory, Oregon State University, Corvallis, for their help in preparing the manuscript. Literature Cited Brady, N C. 1974. The nature and properties of soils. 8th ed. MacMillan, Inc., New York. FuRNlss. R. L., AND V. M Carolin. 1977. Western forest insects. USDA For. Serv. Misc. Publ. 1339. Washington, D.C. Little. E L 1971. Atlas of United States trees. Vol. 1. Conifers and important hardwoods. USDA Misc. Publ. 1146. Washington, D.C. MlROV, NT. 1967. The genus Piniis. Ronald Press, New York. Packard, P L. 1970. Pinus ponderosa in Malheur County, Oregon. Madrono 21: 298. Trappe, J M 1977. Selection of fungi for ectomycorrhizal inoculation in nurseries. Annu. Rev. Phvtopathol. 15: 203-222. NOTES ON AMERICAN SITONA (COLEOPTERA: CURCULIONIDAE), WITH THREE NEW SPECIES Vasco M. Tanner Abstract — Historical notes extracted from a taxonomic revision of American representatives oiSitona Gerniar are presented. Described as new to science are Sitona alpinensis (Utah to Northwest Territories), hnianti (Arizona), and oregonensis (Oregon to Washington). Preface The author (now 94 years of age) commenced a taxo- nomic revision of the weevil genus Sitona in 1954 and labored with it until January 1977 when advancing age prevented finalization of the manuscript. Because of the great effort he expended on this project, the family has requested that the introductory pages and the descrip- tions of new species be published as his final contribution to science in the journal he founded. Although some of the terminology is outdated, the introduction and de- scriptions are presented as he wrote them. The paratypes of alpinensis and oregonensis were distributed more than a decade ago; it is presumed that those not accounted for here are mostly in the U.S. National Museum and in the British Museum (Natural History). Treated in the unfin- ished manuscript are 23 species; 4 are introduced from Europe, and 19 are regarded as native to America. A review of the full text of the manuscript is in progress. — Editor. Introduction The genus Sitona is rather large, containing between 90 and 100 vaHd species fiom the Palearctic and Nearctic regions. Casey (1888) described 16 species from the western United States, 10 of which are considered as vaUd species in this study. A total of 23 species are dealt with in this treatise; four are introduced species. Sixteen native species were previously described, and three new species are proposed. The weevil species assigned to the genus Sitona by Casey have been for many decades in a nebulous taxonomic state. Thomas L. Casey, the son of Brig. Gen. Thomas Lincoln Casey, graduated from the United States Mil- itary Academy at West Point in 1879 and was admitted to the Corps of Engineers. He re- mained in the military service until his retire- ment in 1912, having reached the rank of colonel. For three years, 1885-87, Casey's official military duties called him to the Pacific Coast. "During this time, many portions of California, Nevada, Arizona, and portions of Texas were explored bv himself in person " (Casey 1888:229). While in California, Casey and several other entomologists in California collected about 3,500 specimens of Cole- optera which he transported to his quarters when he returned to Washington, D.C. Casey's (1888) treatise, Sitoninae, was based largely upon specimens of Sitona he accumulated while stationed in California. He devoted much of his life to acquiring and studying the Coleoptera of America. He died in February 1925. He bequeathed his notable entomological collection to the United States National Mu- seum. Tn order to assure the perpetuity of this valuable collection, Col. Casey s wife, Mrs. Laura Welsh Casey, established a memorial fund to provide for the care and knowledgeable curatorial work in the han- dling and installation of the collection " (Buchanan 1935). The collection consisted of "12,245 named forms with a total of 116,738 specimens and more than 9,200 holotypes " (Buchanan 1935). L. L. Buchanan was appointed to serve as curator. "The curatorial work was started by Mr. Buchanan on 1 April 1926, and was con- tinued half a day at a time, for a period of 5 years " (Buchanan 1935). Buchanan was meticulous in transferring the Casey specimens. "The cardinal rule guid- ing the curatorial work was to preserve exactly Casey's concept of each species. Regardless of occasional conflict with accepted synonyms, Formerly at Life Science Museum, Brighani Young University, Provo, Utali .S46()2 168 January 1987 Tanner: Notes on Sitona 169 Casey's arrangement of specimens was strictly followed; furthermore, steps were taken to virtually guarantee the permanent preserva- tion of this arrangement, so that students, both now and in the future, will have equal assurance that before them stand Casey's ac- tual original series of each species; and not a hodge-podge resulting from accidental mis- placement of specimens or interpolation of later and irrelevant material' (Buchanan 1935:6). I have greatly appreciated the care and ac- curacy exercised by Buchanan as he trans- ferred the specimens into the museum collec- tion. During the course of this study, I had the opportunity of visiting the museum on nine different occasions and studying the species of Sitona as Casey had arranged them. 1 always found Buchanan and his aide and successor. Dr. Rose Ella Warner, very cooperative and helpful. In the 1888 study in which Casey described 16 new native species of Sitona, he did not recognize Say's species Sitona indifferens and S. scissifrons or the two distinctive species S. californicus Fahraeus and S. vittatits LeConte, nor did he consider to any extent the variability in size, color, and color pattern of the species he treated. In 1831, Say (LeConte 1859) discussed 135 species of American weevils, 95 of which he described as new species, including Sitona indifferens and S. scissifrons, both inhabi- tants of Missouri. His description of S. scis- sifrons is brief, but it is more accurate and complete than that of S. indifferens. Because the original type series of S. scis- sifrons was destroyed, and because it is now established that only one good native Ameri- can species inhabits Missouri, in order to fix the identity of S. scissifrons, I have desig- nated a specimen collected at Rock Port, Mis- souri, by R. E. Munson as the Neotype. This Neotype was deposited in the Entomological Collection at the U.S. National Museum, Washington, D.C. The type specimens of LeConte's Sitona sordidus and S. vittatus were loaned to me. These have been studied in connection with a large series of specimens from California. The validation of Sitona californica Fahraeus has been considered in some detail in the treatment of this species in the main text of this studv. History The genus Sitona was proposed by Germar (1817) and was subsequentlv cited by Germar (date ?), Schoenherr (1826, 1834), and Say (1831). Schoenherr (1840) changed the spelling to Sitones from which time it had rather wide usage (LeConte and Horn 1876, Casey 1888). Germar s Sitona has priority over Schoenherr's Sitones. Sitona is the sole genus of the tribe Sitonini, subfamily Thylacitinae (Kissenger 1964). It is distinguished from all other tribes by the punctation and pubescence of the mandibles, which are sharp and without a tooth on their internal edge and curved into a hook at the apex. Some 90 to 100 species are widespread in the Nearctic and Palearctic regions. Some of the useful characters for distinguishing this genus have been listed by the following au- thors of Sitona: 'Character generis: Antennae breviuscu- lae, subtenues; articulis primis funiculi longiusculis, obconicis, reliquis nodosis; clava oblongovalis; rostrum supra planum aut in medio linea impressum, aut sulcatum; occuli majusculi, in plerisque subrotundati, modice prominuli, in nonnullis oblongi, valde prominuli; thorax subteres, lateribus pone madium rotundatus; elytra elongata, apice ro- tundata; humeri obtuse angulati' (Schoenherr 1826:134). "Antennae geniculate, rather short and slender; the scape elongation clavate, reach- ing to the middle of the eyes; funiculus with the first and second joints rather long, ob- conic; the remainder nodose; club elongate- ovate, acuminate. Rostrum short nearly hori- zontal; the apex emarginate, above flat, with an impressed longitudinal line or groove; eyes rather large, sometimes rounded, moderately prominent, or oblong and very prominent. Thorax rounded, with the sides a little dilated beyond the middle, as dilated in the middle; scutellum minute, rounded; elytra elongate, with the apex rounded, the shoulders ob- tusely angulated; legs moderate; femora in- crassated in the middle; tibiae truncate at the apex, unarmed (Stephens 1831:132). "Mandibles lacking scar, punctured, and with pubescence " (Fowler 1891:216). "Antennal grooves deep, short, curving abruptly downwards just behind the anten- nae, scape reaching middle of eyes, funicle 170 Great Basin Naturalist Vol. 47, No. 1 7-jointed, joints 1 and 2 thick, 3-7 shorter, club elongate, ringed eyes prominent, round to oblong; front coxae contiguous, hind ones widely separated; claws slender, divergent, appendiculate" (Blatchley and Leng 1916: 140). "Scape shorter than breadth of head includ- ing eyes" (Joy 1932:176). ^'Sitona normally lacks the mandibular scar in the adult and its larva has spiracles with paired annulate air tubes" (Crowson 1955: 165). "Rostrum broad and short, and with im- pressed median line; head behind eyes not much broader than base of rostrum" (Kevan 1959:251, 259). 'Tarsal claw with auxiliary clawlike seta" (Kissenger 1964:23). In this study the male genitalia have proven to be of value in separating the species; female genital structures are poorly developed and of little, if any, value in the classification of spe- cies in this genus. The above characterizations of Sitona help to identify this genus. The following are some of the major characteristics which have helped to separate the species of Sitona: (1) Inner margin of eye not prominent; inner margin of eye prominent; (2) prothorax with distinct me- dian vitta; prothorax without distinct median vitta; (3) elytra without erect setae; elytra with erect setae; (4) thorax finely punctured; thorax deeply punctured; (5) beak and front sulcate; beak and front not sulcate; (6) aedeagus with pointed median lobe; aedeagus with angular median lobe; (7) size of species specimen (a) small or (b) large; (8) elytra tessellate or not tessellate. Specimens of a species will fall into one or the other of the above couplets but will also be distinctive in a number of other characteris- tics. These extrinsic and intrinsic characters within a species, which will affect the color, color pattern, size, and shape of individuals, color and density of body scales, and bodily structures will then need to be carefully stud- ied and recorded. In this study much time has been spent checking type specimens of the Casey Collection with many specimens from type areas. This has necessitated the syn- onymizing of a number of Casey's species. As early as 1886, Casey disclosed that the only specimen with which he was concerned was the specimen he described. "It will be ob- served that the descriptions refer in all cases to the single specimen assumed as the type"; and "I have preferred, therefore, in the exist- ing state of knowledge, to describe one defi- nite type and give such general remarks as may indicate the variation exhibited by the material at hand (Casey 1886). My study of the Casey Collection oi Sitona specimens, the comments made by Buchanan, and the observation by R. E. Blackwelder (1950) that "on the average, nearly half of the species named in the collec- tion were described by Casey and consist of a holotype and sometimes a few paratypes, ' have convinced me that if Casey, as he de- scribed the above-mentioned native species, had been provided with more specimens for his study and had noted the extent of variation upon which to base each of his new species, the treatise of the Sitona in 1888 would have been much improved. An examination of Casey's Sitona speci- mens revealed that he had very few speci- mens of most of the species he described. His Sitona paper and the U.S. National Museum catalog accession record of the type specimens of Sitona , transferred from the Casey Collec- tion by Buchanan in April 1927, show the following were represented: extrusus 3, type (2 paratypes missing) -1-1 ex. Colo.; varians 13, type; margaritarus 2, type (paratype miss- ing); procerus 1, type; occidentalis 2, type (+1 paratype); eximius 4, type ( + 3 paratypes); montanus 2, type (+1 paratype); nebnlosus 1, type; alternans 1, type; osculans 2, type (paratype missing); prominens 2, type (+4 ex.); hispidiceps 2, type (1 paratype +6 ex.); augustulus 1, type (+1 ex.); explicitus 1, type (+10 ex.); apacheanus 2, type (paratype miss- ing); sparsiis 1, type. NewTaxa Sitona alpinensis, n. sp. Fig. 1 Derm black, scales small, some round, elongate, dense, colored white, brown, black, some iridescent; setae short, black and white, obscurely interspersed among the scales. Head as long as rostrum, wider at base than rostrum; interocular space as wide as length of head, occiput punctate, concealed by scales and setae. Eyes large, slightly ovate, some scales, but no long setae over the dorsal inner January 1987 Tanner: Notes on Sitona 171 Fig. 1. Sitona alpincnsis: dorsal aspect of adult, dorsal and lateral aspects of median lobe of male genitalia. margin of eye. Rostrum concave, sulcus deep, extends from fovea between eyes to apical flattish area of rostrum. Antenna reddish brown; scape extending to middle of eye; first joint of funicle longer than second; second as long as segments 3-4 combined; club as long as segments 4-7 combined; scrobes deep, di- rected downward, areas covered with scales between posterior margin of scrobe and ante- rior margin of eye. Prothorax convex, densely covered with scales and decumbent setae; widest before the middle, wider than long, constricted and slightly elevated at apex; base and apex truncate; punctures deep and nu- merous, lateral and medial vitta of white scales and setae; scutellum with white setae. Elytra twice as long as wide, sides parallel two-thirds of length, greatest convexity near declivity, costate, striae punctured, extend- ing from base to apex of elytra; with humeral carina; scales small, vitta of white ones ex- tending posteriorly, sutural area with brown scales, some blotches of black scales in declivi- tous area; apex rounded, moderately acumi- nate. Legs, posterior femora extending to pos- terior margin of fourth ventrite; clothed with white decumbent setae, club of femora mod- erate in size with a few small white scales; prosternal coxal cavities open. Ventrites 1-2 about equal in width, 3-4 shorter and equal in width, segment 5 as wide as 3-4 combined; all segments clothed throughout with white se- tae and scales. Pro-, meso-, and metasternites uniformly clad with white setae and few scales. LENGTH: 5.2-7.1 mm; breadth: 2.3-2.9 mm. Type locality: Holotype, Glacier Lake (Emerald Lake), Mount Timpanogos, Utah County, Utah, elevation 10,000 feet; July 1941 (Vasco M. Tanner); allotype, same data as holotype; 20 paratypes: 7, Glacier Lake (Emerald Lake), Mount Timpanogos, eleva- tion 9,800 feet (L. F. Braithwaite, S. K. Tay- lor, and V. M. Tanner); 3, Hidden Lake, Mount Timpanogos, Utah County, Utah, ele- vation 9,700 feet, 27 July 1940 (C. L. Hay- ward); 3, Aspen Grove, BYU campus envi- rons. Mount Timpanogos, Utah County, Utah, elevation about 6,500 feet (Lowell Miller, V. M. Tanner); 1, Bear Paw Mt., Mon- tana, September 28 (Hubbard and Schwarz); 1, Helena, Montana (collection of C. W. Leng); 1, Gallatin Val., Montana, 10 July 1907 (Wic^ham Collection, 1933); 1, Gallatin Countv, Montana, elevation 9,400 feet, 10 Julv 1900 (E. Koch); 1, Good Hope, N.W.T., 20 June 1931, Lot 237 (Owen Bryant), found on dwarf pea. Astragalus sp.; 1, Yukon Cross- ing, Y.T., Can. 24, Vol. 11 (J. M. Jossup). The holotype, allotype, and one paratype 172 Great Basin Naturalist Vol. 47, No. 1 are in the Life Science Museum, Brigham Young University. The remaining paratypes were distriliuted more than a decade ago, but no record was kept of where they were sent. CHARACTERISTICS: Sitonci alpinetisis is re- lated to S. cylindricollis Fabricius in body shape and color of scales, but alpinensis is a larger species, the rostrum concave, sulcus deep, extending from fovea between eyes to apical flattish area of rostrum. Eyes are large and prominent. Elytra with well-developed costae at least on odd-numbered interstriae. The genitalia oi alpinensis are distinctive. The median lobe is broader, shorter, and with two orificial plates. Sitona alpinensis is a high-alti- tude form, having been collected only in the Hudsonian and subalpine zones. Sitona bnjanti, n. sp. Fig. 2. Form robust, derm black; scales and setae black, except white scales on medial vitta of prothorax and lateral vittae of elytra; white scales and setae on ventrites and legs. Head longer and wider than rostrum; sulcus promi- nent, deep, extending from fovea between the eyes to carina of the rostral disc; frontal of head between eyes flat; eyes prominent, elon- gated, two-thirds as long as the head; inner margin slightly elevated above margin of head; deep punctures on head and rostrum; long black and silvery setae on the rostrum and head; scrobes deep and discernible from above; antennae dark rufous; scape of anten- nae reaching middle of eye; first joint of funi- cle as long as joints two and three combined; club large, as long as segments 3-7 combined. Prothorax slightly wider than long; not con- stricted at apex; widest at middle, apex and base equal; thickly punctured and covered with black scales and setae, except for a prominent medial vitta of small elongate white scales. Elytra three-fourths as wide as long; sides straight and parallel in basal three- fourths, acutely rounded at apex; disc convex, basal area not elevated, surface without striae, middle of disc punctate, closely covered with small elongate black scales and black, decum- bent setae; lateral vittae of white scales ex- tending from humeri to umbones; declivitus and covered with white scales and setae from umbones to apex. Legs uniformly brownish in color, clothed with long, decumbent, silvery Fig. 2. Sitona hryanti: dorsal aspect of adult. setae; ventrites with thick, low-lying, whitish scales and setae. LENGTH; 4 mm; width: 1.5 mm. Type locality: Flagstaff", Coconino Countv, Arizona. 3-VIII-1936. Owen Bryant, collec- tor. I take pleasure in naming this species after Owen Bryant who was a very discerning collector. He was a fre(juent visitor at Brigham Young University and contributed more than (SOO specimens of Curculionidae to the entomological collection of the Univer- sity. The unique holotype is in the Life Science Museum, Brigham Young University. Sitona hryanti is a distinctive species. It is small in size, robust in form, with broad, short head and rostrum, medial vitta on prothorax and with lateral vittae on elytra. Sitona oregonensis, n. sp. Fig. 3. Derm black, robust, elongate, scales ovate, dense, white, brown, and black in color; black January 1987 Tanner: Notes on Sitona 173 Fig. 3. Sitona oregonensis: dorsal aspect of adult, dorsal and lateral aspects of median lobe of male genitalia. scales in patches along intervals of elytra; scales on ventral segments dense, white, elongate, and intermixed with low-lying se- tae. Head wider than long; head and beak squamose and punctate; few short brown se- tae bordering the eyes; long white setae on rostrum, intermixed with iridescent scales; space between eyes level, divided by deep sulcus, which extends to central fovea of ros- trum; eyes prominent, noticeable, convex, in- ner margins slightly elevated above margin of head; antennae dark rufous; first joint of funi- cle as long as joints two and three combined; scrobes deep and discernible from above. Prothorax at middle considerably wider than long; elevated in middle, sloping to apex and base; strongly constricted at one-fifth the length from apex on the sides; base feebly constricted, disc convex, sides arcuate surface punctures obscured by covering of elongate scales; trivittate, marginal stripes well devel- oped, median one narrow; base and apex un- equal. Scutellum well developed, covered by white scales. Elytra three times as long as the prothorax and about twice as long as wide; sides straight and parallel in basal three- fourths, acutely rounded at apex; disc convex; basal sutural area slightly elevated; intervals tessellate with black scales and setae, medial area with dark bands, lateral portions with bands of white scales; umba with black scales; punctation obscured by dense covering of scales and setae; sparse white setae along lat- eral and posterior area. Legs densely covered with light, decumbent setae, scales sparse; venter clad with dense white scales and low- lying setae. LENGTH; 5.6-6.1 mm; breadth: 2.6-2.9 mm. The median lobe of the aedeagus is short, narrowed toward the rounded apex. HoLOTiTE; Tigard, Washington County, Oregon, ll-V-1944 (Anderson), on leaves of lupine. Allotype: Tigard, Washington County, Oregon, ll-V-1944 (Anderson). Paratypes: 5, Tigard, Washington County, Oregon, ll-V-1944 (Anderson); 5, Cornelius Pass, Washington County, Oregon, 9-IV- 1936 (K. Gray and J. Schub); 2, Portland, Multnomah County, Oregon, 8-V-1941 (J. Schuh)on Russell lupine; 1, Longview, Cowl- itz County, Washington, 16-IX-1944 (Ander- son); 1, Forest Grove, Washington County, Oregon, 8-V-1938 (mech trap); 1, Sleila- comm. Pierce County, Washington, 24-V- 1945 (Forsell) on lupine leaves. 174 Great Basin Naturalist Vol. 47, No. 1 The holotype, allotype, and five paratypes are in the Life Science Museum, Brigham Young University. The remaining paratypes were distributed more than a decade ago, but no record was kept of where they were sent. The robust size of the females, vittate prothorax, tessellate elytra, elongate, broad, parallel sides, and angular apices of the me- dian lobe of the aedeagus are distinctive char- acteristics of oregonensis which distinguish it from related species californicus, prominens, and liipina. Literature Cited Blackwelder, R. E 1950. The Casey Room: memorial to acoleopterist. Coleopterists' Bull. 5: 71. Blatchley, W. S., and C. W. Leng. 1916. Pages 140-144 in Rhynchophora of northeastern America. Nature Pub. Co., Indianapohs, Indiana. Buchanan, L. L. 1935. Thomas Lincoln Casey and the Casey Collection of Coleoptera. Smithsonian Misc. Coll. 44(1); 1-15. Casey, T. L. 1886. Descriptive notes of North American Coleoptera I. Bull. California Acad. Sci. 2: 162. 1888. On some new North American Rhyn- chophora I. Ann. New York Acad. Sci. 4:279-296. Crowson, R a 1955, The natural classification of the families of Coleoptera. Lloyd, London, 214 pp. Fowler, W W 1891. The Coleoptera of the British Is- lands 5: 217, Germar, E F 1817. Magazin fiir Entomology, Halle 2:3.34-341. Joy, N H 1932. A practical handbook of British beetles. Pages 176-178. Kevan, D. K 1959, The British species of the genus Sitona Germar (Coleoptera: Curculionidae). Ent. Mon. Mag. 95:251-261. KISSENGER, D. G. 1964. Curculionidae of America north of Mexico: a key to the genera. Ta.xonomic Publica- tions, South Lancaster, Massachusetts. 143 pp. LeConte, J L. 1859, The complete writings of Thomas Say on the entomology of North America. Vol, I, Bailliere Brothers, New York, LeConte, J. L., and G. H. Horn. 1876, The Rhyn- chophora of America, north of Mexico. Proc. Amer. Phil. Soc. 15: 113-115. Say, T 1831. Descriptions of North American Curculion- ides and an arrangement of some of our known species agreeably to the method of Schoenherr. New Harmony, Indiana. 30 pp. Reprinted in J. L. LeConte, 1859. Schoenherr, C J. 1826, Curculionidum dispositio me- thodica. Page 134, Genus 67, Sitona Germ. Dej. — Brachyrhimis Billb. — Turculio Auctorum religuorum, 1834. Genera et species Curculionidum, Vol. 1. 669 pp. 1840, Sitones. Pages 253-281 in Genera et species Curculionidum VI, 1. 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TABLE OF CONTENTS Competition for food and space in a heteromyid community in the Great Basin Desert. Cliflf A. Lemen and Patricia W. Freeman 1 Sequence of epiphyseal fusion in the Rocky Mountain bighorn sheep. Danny Walker. 7 Parasites of mottled sculpin, Cottus bairdi Girard, from five locations in Utah and Wasatch counties, Utah. Richard A. Heckmann, Allen K. Kimball, and Jeffery A. Short 13 Effects of artificial shading on distribution and abundance of juvenile chinook salmon (Oncorhynchus tshawytscha) . William R. Meehan, Merlyn A. Brusven, and John F. Ward 22 Drosophila pseudoobscura (Diptera: Drosophilidae) of the Great Basin IV: a release experiment at Bryce Canyon. Monte E. Turner 32 Robber flies of Utah (Diptera: Asilidae). C. Riley Nelson 38 Elemental compartmentalization in seeds oiAtriplex triangularis and Atriplex confer- tifolia. M. A. Khan, D. J. Weber, and W. M. Hess 91 Plant community changes within a mature pinyon-juniper woodland. Dennis D. Austin 96 Consumption of fresh alfalfa hay by mule deer and elk. Dennis D. Austin and Philip J. Urness 100 Helminth parasites of the Wyoming ground squirrel, Spermophilus elegans Kennicott, 1863. Larry M. Shults and Nancy L. Stanton 103 Observations of captive Rocky Mountain mule deer behavior. Douglas K. Halford, W. John Arthur III, and A. William Alldredge 105 Effects of osmotic potential, potassium chloride, and sodium chloride on germination of greasewood (Sarcobatus venniculatus). James T. Romo and Marshall R. Hafer- kamp .' 110 Big sagebrush (Artemisia tridentata vaseyana) and longleaf snowberry (Symphoricar- pos oreophilus) plant associations in northeastern Nevada. Paul T. Tueller and Richard E. Eckert, Jr 117 Habitat and community relationships of cliffrose (Cowania tnexicana var. stansburi- ana) in central Utah. K. P. Price and J. D. Brotherson 132 Alpine vascular flora of the Ruby Range, West Elk Mountains, Colorado. Emily L. Hartman and Mary Lou Rottman 152 Douglas-fir dwarf mistletoe parasitizing Pacific silver fir in northern California. Robert L. Mathiasen and Larry Loftis 161 A disjunct ponderosa pine stand in southeastern Oregon. Arthur McKee and Donald Knutson 163 Notes on American Sitona (Coleoptera: Curculionidae), with three new species. Vasco M . Tanner 168 THE GREAT BASIN NATURALIST Volume 47 No. 2 30April1987 Brigham Young University MCZ LIBRARY SEP 1 6 1987 HARVARD UNIVERSITY 2 '■■ '^■^•v3» / ' V \ GREAT BASIN NATURALIST Editor. Stephen L. Wood, Department of Zoology, 290 Life Science Museum, Brigham Young University, Provo, Utah 84602. Editorial Board. Kimball T. Harper, Chairman, Botany and Range Science; Ferron L. An- dersen, Zoology; James R. Barnes, Zoology; Hal L. Black, Zoology; Jerran T. Flinders, Botany and Range Science; Stanley L. Welsh, Botany and Range Science. All are at Brigham Young University. Ex Officio Editorial Board Members include Bruce N. Smith, Dean, College of Biological and Agricultural Sciences; Norman A. Darais, University Editor, University Publications; Stephen L. Wood, Editor, Great Basin Naturalist. The Great Basin Naturalist was founded in 1939. The journal is a publication of Brigham Young University. Previously unpublished manuscripts in English pertaining to the biological natural history of western North America are accepted. The Great Basin Naturalist Memoirs series was established in 1976 for scholarly works in biological natural history longer than can be accommodated in the parent publication. The Memoirs appears irregularly and bears no geographical restriction in subject matter. Manuscripts for both the Great Basin Naturalist and the Memoirs series will be accepted for publication only after exposure to peer review and approval of the editor. Subscriptions. 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See Notice to Contributors on the inside back cover. 6-87 650 30643 ISSN 017-3614 The Great Basin Naturalist Published AT Provo, Utah, by Brigham Young University ISSN 0017-3614 Volume 47 30 April 1987 No. 2 ECOLOGICAL COMPARISON OF SYMPATRIC POPULATIONS OF SAND LIZARDS {COPHOSAURUS TEXANUS AND CALLISAURUS DRACONOIDES) Donald D. Smith' ", Philip A. Medica' \ and Sherhnrn R. Sanborn^ Abstr.act — Sympatrie populations ofCophosaiinis texauus and Callisaunts draconoidcs were periodically sampled from March 1973 through April 1974 at Burro Creek, Mohave County, Arizona. CaUisaurits were also sampled at Rock Vallev, Nve County, Nevada. Se.x ratios were skewed in favor of males in the adult Cophosaurus but were equal in both adult populations of Callisaurus. Both species became sexually mature as yearlings. Mean clutch sizes were 3.55 (±0.83) for Cophosaurus, and 4.25 (±1.08) and 5.07 (±1.3.3) for Callisaurus at Burro Creek and Rock Valley respectively. Evidence of multiple clutches was exhibited by both species. Egg weight/body weight ratios for both species and clutch weight/body weight ratios for Cophosaurus were notably smaller than previously reported. At Burro Creek both species were highly insectivorus, with orthopterans comprising the largest food group of each. Niche overlap for food was high at the ordinal level, but at the familial level it is apparent that Callisaurus probably fed in the more xeric areas of the riparian habitat. No differences were found in the temperature responses of these two lizards. However, minor temporal separations and substantial spatial partitioning were observed. Callisaurus preferred sandy open areas, while Cophosaurus preferred the presence of some rocks and boulders. Ecological studies of Callisaurus dra- conoides have been conducted by Kay et al. (1970), Pianka and Parker (1972), Tanner and Krogh (1975), and Vitt and Ohmart (1977). Studies of Cophosaurus texanus have been done bv Johnson (1960), Ballinger et al. (1972), Shrank and Ballinger (1973), Engeling (1972), and Howland (1984). Clarke (1965) studied the ethology of both of these lizards as well as that of Holbrookia. Prior to our field work, no comparative ecological study had been done of sympatrie populations of Cal- lisaurus draconoides and Cophosaurus tex- anus. These two sand lizards are recognized as being closely related (Peters 1951, Clarke 1965) and exhibit geographic distributions that are usually mutually exclusive. It is hoped that this study will provide insights into their descriptive ecological characteristics and some of the interrelationships of these two populations. In the spring of 1966, P. A. Medica col- lected a single specimen of Cophosaurus tex- anus near Burro Creek, 32 km S of Wikieup, Mohave County, Arizona. In May 1970, D. D. Smith discovered C. texanus near the same locality to be sympatrie with Callisaurus draconoides. This area is described in Steb- bins (1966) as a disjunct locality in the distri- bution of Cophosaurus. Another pair of saurian species not often found to be sym- patrie were also present at the study site, Uta stansburiana and Urosaurus ornatus. Other species of reptiles and amphibians observed at the study locality include Cnemidophorus tigris, Sauromalus ohesus, Sceloporusmagis- ' University of California. Laboratory of Biomedical and Environmental Sciences, 900\eteran .Avenue, Los .AnKeles, California 90024. "Present address; Department of Pathology , University of Kansas Medical Center, :39th Street and Rainbow Boulevard. Kansas City, Kansas 6610.3. ^Present address; Natural History Museum of Los Angeles County. Section of Herpetology , 900 Exposition Boulevard, Los .\ngeles. California 90(X)7 ^Department of Biology, California State University. Long Beach, California 90840. Present address: 1.361.5 .Arnold Drive, Glen Ellen, California 95442. 175 176 Great Basin Naturalist Vol. 47, No. 2 ter, Crotalus mitchelli, Kinosternon sonorense, Bufo microscapJius, and Hyla arenicolor. Additional noteworthy locality records have been recorded for Thamnophis cyriopsis (Smith and Medica 1973), Eumeces gilberti (Medica and Vitt 1974), and Masti- cophis bilineatus (Medica and Maza 1974). Methods Between 3 March 1973 and 7 April 1974 nine weekend field trips were taken to Bmro Creek (15 km W of Bagdad), Mohave County, Arizona. Field work normally began about 0700 hours (hr) and continued until approxi- mately 1400 hr when most lizard activity had ceased. Then in the evening we sampled lizards again between 1730 hr and sunset. Lizards were collected along either side of Burro Creek and from the water's edge some- times up the arroyos and onto the surrounding bajadas. Lizards were collected by noosing or by shooting with BB guns or .22-caliber re- volvers loaded with #12 shot cartridges. Each time a lizard was secured, the follow- ing data were recorded: cloacal temperature, air temperature at about 2 cm, and soil surface temperature using a Schultheis quick-reading thermometer 20-70 C. The habitat type, soil type, and lizard's activity were also recorded. The animals were then frozen with dry ice and transported to the laboratory for autopsy. From the Burro Creek locality 116 Cophosaii- riis texanus and 132 CaUisaiirus draconoides were removed for analysis. In addition, dur- ing the summer of 1973, a parallel sample of 91 C. draconoides was collected from Rock Valley, Nye County, Nevada (322 km NW of Burro Creek), to be analyzed similarly to those from Burro Creek for information on reproduction. This was done in an effort to gain insight into latitudinal variation in this species during the same season and to obtain further baseline data for comparison with the well-studied population of Frenchman Flat reported by Tanner and Krogh (1975). All specimens have been deposited at the Los Angeles County Museum of Natural History, Section of Herpetology. In the laboratory, snout-vent (s-v) and tail lengths were measured to the nearest mm, weights were recorded to the nearest mg, and the lizards were autopsied to determine re- productive condition. Ovaries and oviducal eggs were weighed, and clutch size was deter- mined by counting yolked follicles >3 mm in diameter, oviducal eggs, and/or corpora lutea. In males the testes were weighed and their length and width measured. The amount of fat present and the weight of stomach contents of both sexes were also recorded. Stomach vol- ume was determined by displacement of wa- ter in a graduated centrifuge tube and mea- sured to the nearest 0.01 ml as described by Sanborn (1972). The stomach contents were separated and identified to family whenever possible, and their volume estimated. Results and Discussion Reproduction Sex ratios. — Sex ratios of Cophosaurus were skewed in favor of males in individuals >55 mm s-v, at 63:40, while in smaller indi- viduals sexes occurred equally at 7:6. Sex ra- tios of adult Callisaurus at both Burro Creek and Rock Valley were close to one-to-one with male-to-female ratios of 53:50 and 42:40 for individuals >55 mm at Burro Creek and >60 mm at Rock Valley respectively. In contrast, sex ratios of yoimger Callisaurus from both localities were skewed in favor of females with sex ratios of 12:17 and 3:6 for Burro Creek and Rock Valley respectively. Engeling (1972) concluded sex ratios of a population of marked Cophosaurus were equal. The disparity observed by us may be due to sampling error. Since male Cophosau- rus often patrol, display, and observe from points of prominence, they would consis- tently be the most obvious and therefore the most commonly collected of the two sexes. The males are also larger and therefore easier to see. These arguments would also seemingly be true for Callisaurus, except that points of prominence are less common in the habitats most preferred by them. If it is true, however, it would agree with findings for the smaller- sized group with females being more com- mon. If the females truly are more abundant in this species, the causes are unknown. Age at maturity — At Burro Creek during June and July no female Cophosaurus was found below the minimum reproductive size of 55 mm s-v. Only one Callisaurus was found below that s-v length, and it was a 52-mm female found on 1 June 1973. Similarly, no male Cophosaurus was found in June or July April 1987 Smith etal.: Sand Lizard Ecology 177 below the length of 55 mm s-v, and the smallest weight of testes was 0.043 g. In con- trast, three Callisaiinis from Burro Creek in early June were found to measure <55 mm, had testes weights of 0.013, 0.002, and 0.001 g, and were probably not yet reproductive. Similarly sized male Callisaurus were not found in late June or July. At Rock Valley no female Callisaurus was collected below 60 mm s-v in the months of June or July. However, two females <55 mm collected in late May were not yet reproduc- tive with ovarian weights of only 2 mg each. During June and July only one <60 mm Cal- lisaurus male was collected. It was collected on 8 June, measured 56 mm s-v, and had a testes weight of only 2 mg. Engeling (1972), Ballinger et al. (1972), Howland (1984), Pi- anka and Parker (1972), and Tanner and Krogh (1975) agree that most sand lizards be- come reproductive as yearlings. Female reproductive cycle — The first evidence of follicular development at Burro Creek in 1973 was exhibited by Callisaurus that contained yolked follicles 2 to 7 mm in diameter on 28 April. Unfortunately, com- parable samples o(Cophosaurus could not be obtained at this sampling period. By 1 June adequate populations of both Callisaurus and Cophosaurus were located in sympatry, and series of 10 and 13 respectively were col- lected. Reproductive condition oiCoph-osau- rus varied from small yolked follicles 3-5 mm in lizards <60 mm s-v to oviducal eggs in females >60 mm s-v. Callisaurus <60 mm were usually determined to be prereproduc- tive, and females >60 mm s-v contained en- larged yolked follicles 3-9 mm in length or oviducal eggs. The reproductive season for both species apparently began by early May and was over in August. Callisaurus from Rock Valley probably ceased reproductive ac- tivities two to three weeks earlier than those at Burro Creek. Ballinger et al. (1972) found follicles in Cophosaurus from 8 April through 9 August and oviducal eggs from 27 April through 9 August. Engeling (1972) concluded that their reproductive season was from March through August. Howland (1984) stated that oviposi- tion extended from mid-May to late August. In Callisaurus, Pianka and Parker (1972) found yolked follicles from April through Sep- tember. Vitt and Ohmart (1977) found ovidu- Table 1. Mean clutch size ior various size groups of Cophosaurus tcxanus and Callisaurus draconoides, ac- cording to their availabiUty. Snout-vent length, mm X Range N Cophosaurus texanus (Burro Creek) 55-57 3.20(±0.45) 3-4 5 58-60 3.57(±0.79) 3-5 7 61-63 3.54(±0.88) 2-5 13 64 + 4.00(±1.15) 3-5 4 All sizes 3.55(±0.83) 2-5 29 Callisaurus d raconoides (Burro Creek) 55-59 3.00 3 1 60-64 3.50(±0.58) 3-4 4 65-69 4.43(±1.09) 2-6 14 70-74 4.44(±1.13) 2-6 9 All sizes 4.25(±1.08) 2-6 28 Callisaurus d raconoides (Rock Vallev) 65-69 4.00(±1.15) 3-5 4 70-74 4.82(±0.98) 3-6 11 75-79 5.22(±1.30) 3-7 9 80+ 6.20(±1.64) 4-8 5 All sizes 5.07( + 1.33) 3-8 29 cal eggs from May through August with vitel- logenesis beginning by mid-April. And Tan- ner and Krogh (1975) found follicles and ovid- ucal eggs from late May into July, with most seen in June. Table 1 shows the mean clutch size for vari- ous size groups of sand lizards. Mean clutch sizes for all size groups are 3.55 (±0.83) for Cophosaurus and 4.25 (±1.08) and 5.07 (±1.33) for Callisaurus at Burro Creek and Rock Valley respectively. There is a marked trend of an increase in clutch size with an increse in s-v length in both populations of Callisaurus, but this trend is not apparent in Cophosaurus. One record of a 69-mm Cal- lisaurus collected on 8 September at Burro Creek with one 4-mm yolked follicle was deleted from this table, as it was not represen- tative of the rest of the September sample and was the only record of a single-egged clutch. It is not known whether this ovum would have been deposited or resorbed. The smallest Cophosaurus female found to be reproductive was 55 mm s-v with three yolked ovarian follicles 5 mm in diameter. The smallest reproductive Callisaurus from Burro Creek measured 58 mm s-v and contained three 7-mm follicles, while the smallest repro- ductive female from Rock Valley measured 65 mm s-v and had three oviducal eggs 17 mm long. Ballinger et al. (1972) and Engeling 178 Great Basin Naturalist Vol. 47, No. 2 Table 2. Clutch size and fat body weights (g) for female sand lizards > .55 mm s-v. Date is mean date of collection. Day and s-v range X clutch N repro/ X fat body month in mm (mean) size Range N examined weight (S.b.) Cophosaurus (Burro Creek) 28 Apr — — — — — 1 Jun 56-64(60.5) 3.55(±0.69) 3-5 10/13 .068(±.067) 23 Jun 55-64(60.3) 3.50(±1.07) 2-5 8/9 .056(±.041) 21 Jul 59-64(61.3) 3.60(±0.84) 3-5 9/9 .014(±.018) 8 Sep — — — 0/5 .038(±.031) 6 Apr — — — 0/3 '.07.3(±.059) Callisaunis (Burro Creek) 10 Mar — — — 0/4 .0.33(±.066) 7 Apr — — — 0/5 .052(±.056) 28 Apr 67-70(68.8) 4.80(±0.84) 4-6 5/7 .161(±.105) 1 Jun 58-70(65.7) 4.29(±1.11) 3-6 6/9 .047(±.067) 23 Jun 60-70(65.0) 3.83(±0.41) 3-4 6/8 .073(±.057) 21 Jul 65-75(70.8) 4.20(±1.40) 2-6 9/9 .023(±.038) 8 Sep — — — 0/6 .069(±.046) 6 Apr — — — 0/2 .161(±.099) Callisaunis (Rock Vallev) 2 Mav 72-82(77.0) 5.50(±2.12) 4-7 2/5 .153(±.115) 31 Mav 71-84(77.3) 6.25(±1.04) .5-8 6/7 .191(±.100) 8 Jul' 65-82(72.9) 4.73(±1.01) .3-6 11/13 .197(±.223) 25 Jul 67-79(72.5) 4.25(±1.16) 3-6 8/12 .227(±.267) 13 Sep — — — 0/1 .457 Table 3. Ranges of sizes of hatchling sand lizards found in September at Burro Creek, Mohave County, Arizona. Species Sex Snout-vent length, mm Weight, g Cophosattrus females Cophosaurus males Callisatinis females Callisaunis males 38-45 1.5-3.0 38-50 1.5-3.6 .30-46 0.7-3,3 40-55 1.8-4.9 (1972) both found Cophosaurus to become reproductively mature at about 50 mm s-v, and Howland (1984) found them to matvue between 52 and 55 mm s-v. Kay et ah (1970) found Callisaunis to become reproductive at 65 mm, Pianka and Parker (1972) recorded the smallest at 63 mm, and Tanner and Krogh (1975) found oviducal eggs in females as small as 66 and 67 mm s-v. The mean clutch size oi Cophosaurus has been variously reported at 2.8 (Hulse 1973), 3.1 (Howland 1984), 4.0 (Parker 1973), 4.6 (Vitt 1977), 5.0 (Johnson 1960), and 6.0-6.1 (Ballinger et al. 1972, Engeling 1972); and the pattern appears nonclinal and irregular as de- scribed by Fitch (1985). The mean clutch size o( Callisaurus has been recorded at 4.4 (Pi- anka and Parker 1972), 4.5 (Vitt 1977, Tanner and Krogh 1975), and 4.6 (Vitt and Ohmart 1977), being apparently rather consistent throughout its range. The mean of 4.25 eggs per clutch recorded at Burro Creek then is a reported low associated with range periphery and the mean of 5.07 at Rock Valley a reported high probably associated with a short-term consideration of high precipitation, as with the increased fecundity found in Uta from the same location during that same year (Medica and Turner 1976). Table 2 shows mean clutch size, number of animals found to be reproductive, and x fat body weights of female lizards sampled at var- ious intervals. There was a trend for Callisau- rus from Rock Valley to exhibit reduced fe- cundity through the breeding season. This trend was not as apparent for Cophosaurus and Callisaurus from Burro Creek. Peak peri- ods of reproduction were in late July for both Burro Creek populations, while the Callisau- rus from Rock Valley peaked in early July. Minimum mean fat body sizes were recorded for both Cophosaurus and Callisaurus at Burro Creek in the month of July, while the largest were recorded for both in the month of April. Callisaurus from Rock Valley main- tained large fat bodies throughout the sam- pling period, probably due to unusually large amounts of precipitation presumably result- ing in large quantities of food production dur- ing that year (Medica and Turner 1976). Vitt April 1987 Smith etal.: Sand Lizard Ec;olocy 179 Table 4. Reproductive data oi Cophosauni.s and Callisaurus based solely upon females carrying oviducal eggs. All mean values ± one standard deviation. Cophosatinis Calli Burro Creek Rock Vallev Number of females X s-v length, mm X weight, g X clutch size X weight of clutch, g Clutch wt./body \vt. ratio X weight of one egg, g Egg wt./body wt. ratio 12 61.33 ±2.02 8.169±1.218 4.08 ±0.79 1.270 ±0.326 0.155 0.319 ±0.078 0.039 67.0 ±3. 85 10. 422 ±1.405 4.50±1.05 2.004 ±0.574 0.192 0.443 ±0.0,39 0.043 10 72.7±4.97 13. 375 ±3. 860 4. 20 ±1.48 2. 255 ±1.237 0.169 0.517 ±0.122 0.039 and Ohmart (1977) could find no clear pattern of fat body cycling in Callisaurus females. Evidence of multiple clutches was exhib- ited by both species. A 56-mm Cophosaurus captured 2 June contained three yolked folli- cles 3 mm in diameter and three corpora lutea 1 mm in diameter. Another specimen 60 mm s-v captured on 21 July contained three 3-mm follicles and three 1-mm corpora lutea. Simi- larly, a 69- and a 65-mm Callisaurus from Burro Creek captured on 2 June and 21 July respectively both contained 3-mm ovarian fol- licles undergoing vitellogenesis as well as oviducal eggs 15 mm in length. From Rock Valley a 78-mm Callisaurus captured 24 May contained six 3-mm follicles and seven 17-mm oviducal eggs with corresponding corpora lutea. Another specimen 84 mm s-v from 4 June contained seven 4-mm follicles and eight corpora lutea measuring 2 mm. In addition to the six sand lizards already mentioned, four Cophosaurus between the dates of 1 June and 24 June, one Callisaurus from Burro Creek on 21 July, and one from Rock Valley on 13 July contained 2-mm follicles initiating vitellogen- esis as well as oviducal eggs and/or corpora lutea. Given a reproductive period of at least three months, multiple clutches were proba- bly common in Burro Creek populations of both species and Callisaurus of Rock Valley in 1973. The large range of sizes exhibited by hatchling sand lizards of both species in Sep- tember at Burro Creek also supports this con- clusion (Table 3). Engeling (1972) found Cophosaurus to hatch from June through Oc- tober, and Whitford and Creusere (1977) re- ported similar findings. Most investigators of these lizards have considered them to produce multiple clutches, but the evidence is more conclusive for Cophosaurus (Ballinger et al. 1972, En- geling 1972, Rowland 1984, Johnson 1960, Vitt 1977) than for Callisaurus (Pianka and Parker 1972, Tanner and Krogh 1975). Vitt (1977) and this paper, however, present strong evidence for multiple clutches in Cal- lisaurus. Tinkle (1969, Tinkle et al. 1970) has eluci- dated the concept of reproductive effort and its adaptix e and evolutionary significance as it applies to lizard populations. To facilitate these considerations, we have also tabulated reproductive data (Table 4) based solely on females carrying oviducal eggs. In comparison with published accounts, the Burro Creek populations o{ Cophosaurus and Callisaurus and the Rock Valley Callisaurus exhibited egg weight/body weight ratios of 0.039, 0.043, and 0.039 respectively that are much lower than 0.056 and 0.058 for Cophosaurus and Cal- lisaurus presented by Vitt (1977). The clutch weight/body weight ratio of 15.5% for Cophosaurus is also much lower than the 21.8% presented by Ballinger et al. (1972) for a population oiCopJiosaurus in Texas. In fur- ther contrast to Ballinger et al. (1972), we did not find the mean weight of eggs of Cophosau- rus to be smaller in smaller females. In fact, we generally found the opposite to be true, but not significantly so. The smallest mean oviducal egg weights of 0.171, 0.197, 0.242, and 0.287 were associated with females hav- ing s-v lengths of 64, 64, 59, and 63 mm re- spectiveh', and 64 mm was the largest s-v length for a female of this species at Burro Creek. All four of these small mean egg weights were associated with large clutches of five eggs each. The largest mean egg weight of 0.409, however, was obtained from a 62-mm female, also with five eggs. Male reproductive cycle. — Table 5 shows testicular measurements and fat body 180 Great Basin Naturalist Vol. 47, No. 2 Table 5. Testicular size (mm) and fat body weight for male sand lizards s60 mm s-v. Day is mean date of collection. Day and s-v range X testes X testes X fat body month in mm (mean) N length X width (mm) weight (S.D.)(g) weight (S.D.)(g) Cophosatirus (Burro Creek) 28 Apr 67-71(68.7) 3 6.3 X 4.3 .082(±.020) .054(±.012) 1 Jun 60-74(67,7) 20 6.5 X 5.2 .090(±.023) .0.59(±.048) 23 Jun 60-70(66.2) 6 6.3 X 4.5 .077(±.021) .014(±.009) 21 Jul 62-77(68.3) 13 6.4x5.1 .091(±.024) .027(±.044) 8 Sep 61-70(65.4) 11 3.0 X 2.0 .003(±.002) . 109( ± . 108) 6 Apr 62-69(65.0) 4 5.5 X 4.3 .050(±.01.3) .033(±.023) Callisaurus (Burro Creek) 3 Mar 65-75(71.3) 4 4.0 X 3.0 .038(±.033) .004(±.005) 7 Apr 74-76(75.0) 2 6.0 X 4.5 .102(±.036) .007(±.009) 28 Apr 66-81(74.5) 6 7.7 X 6.2 .175(±.046) .057(±.061) 1 Jun 63-84(76.7) 6 7.0 X 5.2 .147(±.046) .027(±.048) 23 Jun 62-83(75.7) 7 6.9 X 5.3 .105(±.039) .067(±.084) 21 Jul 74-84(77.8) 12 7.4 X 5.3 .118(±.0,33) .031(±.048) 8 Sep 70-75(72.8) 5 3.2 X 2.0 .003(±.002) .092(±.075) 6 Apr 61-82(75.0) 4 5.5 X 4.0 .079(±.0.59) .0.35(±.027) Callisaurus (Rock Valley) 27 Apr 64-87(79.6) 10 7.2 X 5.5 .1.59(±.086) .1.32(±.198) 6 Jun 77-89(83.1) 8 8.6 X 6.3 .256(±.074) .210(±.114) 8 Jul 68-94(82.6) 16 6.3 X 4.9 .139(±.167) .27.3(±.247) 25 Jul 79-90(85.3) 6 5.8 X 3.8 .057(±.016) .514(±.249) 13 Sep 77 1 5x2 .023 1.076 weights of male lizards from Burro Creek and Rock Valley. Minimum testicular measure- ments were obtained during the month of September in all populations. Maximum tes- ticular measurements were obtained for Cophosaurus on 1 June and 21 July, for Cal- lisaurus at Burro Creek on 28 April, and for Callisaurus from Rock Valley during early June. Maximum mean fat body sizes were obtained in the month of September for all populations. Minimal measurements were obtained for Cophosaurus on 23 June, in March and April for Callisaurus from Burro Creek, and in April for Callisaurus from Rock Valley; however, as with females, fat bodies of males from Rock Valley were enlarged throughout 1973. The male reproductive cycles of both lizards have been well studied (Shrank and Ballinger 1973, Pianka and Parker 1972, Tan- ner and Krogh 1975, Vitt and Ohmart 1977), and for the most part our results are compara- ble. However, the maintenance of enlarged fat bodies throughout the reproductive season by Callisaurus at Rock Valley is unusual and probably reflects an unusually good food sup- ply at that locality for that year. Food Habits We have compared food habits of Cophosaurus tcxanus and Callisaurus dra- conoides from Burro Creek at two levels. First, we compared the orders of organisms eaten during the entire sampling period (Figs. 1 and 2). Secondly, we compared orders of organisms consumed on a monthly basis (Table 6). Upon comparison of the pie diagrams, we find that insects comprised over 90% of the diet for both species. However, the quantities of each order consumed by each species varied considerably. Almost 50% of the diet of Callisaurus consisted of Orthoptera and Lepi- doptera, whereas Cophosaurus consumed 18% Orthoptera, about 16% Hymenoptera, and only 10% Lepidoptera and also displayed considerably more dependency upon Cole- optera and Araneida than did Callisaurus. Niche overlap, based on these data and calcu- lated using the formula of Pianka (1973, 1974), is high at 0.88. Our findings at the familial level (unpub- lished data) indicate that niche overlap for these resources in reality may not be this high. Although both species were observed in January 1987 Smith et al.: Sand Lizard Ecology 181 Fig. 1. Food habits of Cophosciiinis tcxanus during 1973 and 1974, indicating percent volume of each cate- gory. Fig. 2. P'ood habits oiCallisaitrus dracunoides during 1973 and 1974, indicating percent vokune of each cate- gory. the riparian habitat (see Activity), Cophosaii- rits tended to feed closer to the stream than did Callisaurus. For e.xample, in the Or- thoptera we find that both species ate acri- dids, but Cophosaurus consumed far fewer acridids than did Callisaurus. Instead, Cophosaurus was found to feed heavily upon tetrigids and tridactylids. In the Coleoptera we saw a similar trend, for of the two lizards only Cophosaurus consumed hydrophilids, omophronids, and psephenids. This trend was not as obvious in other families because they are not characterized by their occurrence in limnological habitats. This may also explain the greater volume of both Hymenoptera and Araneae in Cophosaurus, for there was proba- bly a greater diversity and abundance of mem- bers of both these groups in the riparian habi- tat. Therefore, it is probable that Callisaurus feeds in the more xeric areas of the riparian habitat as indicated by the greater occurrence of acridids, lygaeids, and formicids. During the late summer and early spring when hatchling lizards were abimdant, we found that Cophosaurus occasionally supple- mented their diet with vertebrate prey, par- ticularly Urosaurus ornatus. No vertebrates were found in the stomachs of Callisaurus. Table 6 indicates that the diets of these two lizards are highly variable, and they are prob- ably greatly influenced by blooms, hatches, and phenology as it relates to populations of appropriately sized and edible insects. Throughout the activity season, however, Or- thoptera seemed to constitute the primary food source of both species. Engeling (1972) found that Cophosaurus most frequently ate orthopterans, hemipter- ans, coleopterans, and araneans. Pianka and Parker (1972) found Callisaurus to feed pri- marily on orthopterans and coleopterans in the U.S. and insect larvae and hymenopterans in Sonora, Mexico. Vitt and Ohmart (1975) found Callisaurus to primarily feed on or- thopterans, and to a small extent (<1%) on small lizards. Tanner and Krogh (1975) and Kay et al. (1970) found Callisaurus to primar- ily feed upon hymenopterans and dipterans respectively. Pack (1923) found 10% of the food items consisted of vegetable matter, and 89% consisted of insects, with hymenopter- ans, lepidopterous larvae, neuropterans, hemipterans, and coleopterans represented in that order. Activity Habitat preference. — The plant associa- tion in which the lizards were first encoun- tered gixes an indication as to which habitat was preferred at Burro Creek. Table 7 indi- cates that Cophosaurus was primarily found in the riparian habitat (77.9%) and secondarily in the arrovos (14.2%), being usually re- 182 Great Basin Naturalist Vol. 47, No. 2 Table 6. Food habits oi Cophosaurus texamis (Coph. ) and Callisaurus draconoides {Call .) tor 1973 and 1974 at Burro Creek, Mohave County, Arizona, indicating the percent volume of each category. March 1973 April 7, 1973 April 28, 1973 June 1, 1973 June 23, 1973 Taxon Call. Coph. Call. Coph. Call. Coph. Call. Coph. Call. Arachnida Araneida 5.7 — 2.1 — 1.3 7,5 2,2 11.2 1.7 Insecta Thysanura — — — — — 0,2 Odonata — — — — — — Orthoptera 0.4 — — 21.4 25.8 4,7 22,0 32.8 42.4 Isoptera — — — — — — — — — Hemiptera 2.1 — 1.6 — 4,4 7,7 18,6 4.3 7.0 Homoptera 2.1 — — — — 0,6 0,4 0.7 2.1 Neuroptera — — — 4.3 0.7 1,3 0,8 — 0.6 Coleoptera 2.1 — 2.1 — 0.4 9,3 2,8 10.7 2.5 Lepidoptera 38.9 — 46.6 28.6 44.7 11,5 16,4 24.9 0.9 Diptera 28.2 83.3 34.1 — 14.2 15,4 12,0 2.6 2.5 Hymenoptera .5.4 — 6.8 42.9 2.2 31,2 13,6 1.2 10.9 Unidentified parts 7.1 — 6.2 2.9 6.0 5,9 6,8 7.8 28.8 ISOPODA — — — — — — 2.4 — — Plant MATERIAL 7.9 16.7 0,6 — — 4,7 2.0 3.8 0.9 Lizard (skin, parts) — — — — — — — — — stricted to the edges. Callisaurus, on the other hand, preferred the arroyos (57%), which have the largest expanses of open sandy spaces; secondarily they utilized the riparian association (40.7%). The soil/substrate type in the riparian asso- ciation is sand interspersed with numerous boulders, and this substrate was preferred by Cophosaurus 69.0% of the time. Callisaurus prefers the more open sandy areas and was taken on such substrate 72.0% of the time. Niche overlap calculated by the formula of Pianka (1973, 1974) is higher based on habitat preference (0.71) than on the microhabitat determination of soil/substrate type (0.57). Therefore spatial partitioning is greatest at the level of the microhabitat, with Cophosaurus being characterized as more sa.xicolous than Callisaurus. Similar preferences have also been observed by Clarke (1965) and Engeling (1972), who noted the preferred habitat of Cophosaurus was dry creek beds with a pre- ponderance of flat-surfaced limestone and sandstone. Pianka and Parker (1972) and Tan- ner and Krogh (1975) noted that Callisaurus preferred open areas of desert flats and val- leys. Whitford and Creusere (1977) found Cophosaurus to be a permanent resident of the arroyo-shrub association and a transient resident in open Larrea. Time of activity, — Table 8 shows the fre- quency of collection of Cophosaurus and Cal- lisaurus at Burro Creek during 12 daily time intervals. Cophosaurus was most active be- tween 0900 and 1300 hr with another period of activity initiated after 1700 hr. Callisaurus probably initiated activity a little earlier than Cophosaurus and decreased activity about 1200 hr. Also, they exhibited a less-pro- nounced peak of evening activity. Temporal niche overlap calculated bv the formula of Pianka (1973, 1974) is high at 0.86. Engeling (1972) found Cophosaurus most active in the afternoon, but some activity was observed at nearly all hours of the day be- tween 0919 and 1948 hr. Pianka and Parker (1972) found Callisaurus active as early as 0730 and suggested bimodal diel activity. Tanner and Krogh (1975) found Callisaurus rather heat tolerant, seldom active before 0800, and considered them to remain active throughout the heat of the day. Kay (1970), who has probably done the most extensive activity study, found Callisaurus to be active throughout the day, but showing weak bimo- dality through the summer. Temperature rel.^tionships. — The mean body temperature of Cophosaurus texanus was 38.5 C (± 1.5, n = 73) and of Callisaurus draconoides was 38.2 C (±2.4, n = 96). The mean surface soil temperature and air tem- perature within 2 cm of the soil at the point of capture were 42.0 C (±5. 1, n = 69) and 36.0 C ( ± 4.4, n = 68) for Cophosaurus, and 40.5 C April 1987 Smith etal.: Sand Lizard Ecology 183 Table 6 contiiuied. July 21, 1973 Sept. 8, 1973 April 7, 1974 Copli. Call. Coph. Call. Coph. Call. 14.3 0.3 1.6 0.4 3.3 0.8 — — 6.3 16.8 4.0 — 28.2 54.6 39.2 44.8 5.7 1.1 — -^ 1.1 3.2 — — 1.9 1.6 2.9 7.4 31.6 11.4 11.1 21.8 — 0.6 — 1.2 5.6 8.4 16.5 7.1 7.5 18.4 4.3 3.1 2.5 1.1 9.8 4.1 5.1 0.7 3.6 1.1 4.0 4.5 7.6 2.2 4.0 9.9 12.9 17.6 12.7 6.9 13.4 7.1 9.7 4.5 4.1 — 5.4 0.4 10.9 36.3 5.1 — 3.4 — — — (±7.8, n = 90) and 35.8 C (±5.0, n = 65) for Callisauriis respectively. There are no differ- ences in these respective pairs of means be- tween Cophosaurus and CaUisaurus at the .05 level of significance. Clarke (1965) found the mean body temper- ature of Cophosaurus to be 38.3 C and 39.2 C for CaUisaurus and related this difference to geographic distribution, with CaUisaurus generally living in the warmer locales. Most other studies have also found the mean or median body temperature for CaUisaurus to be 39.1 C or slightlv higher (Packard and Packard 1970, Pianka and Parker 1972, Tan- ner and Krogh 1975). We conclude from our data that there is virtually no difference in the temperature responses of the two species when exposed to the same or similar ambient temperatures as with the two populations at Burro Creek. Muth (1977a, 1977b) has corre- lated and analyzed body temperatures and associated posturing in CaUisaurus. Summary and Conclusions From this study a number of conclusions can be drawn concerning the biology of Cophosaurus and CaUisaurus at Burro Creek and CaUisaurus at Rock Valley. Sex ratios of adult Cophosaurus were unequal in our sam- ples, with a larger number of males being present. This, however, may have been due to sampling error and the fact that males are more obvious. Sex ratios of adult CaUisaurus from both Burro Creek and Rock Valley were approximately equal, but in samples of juve- niles, females outnumbered males. Most males and females of both species be- came reproductively mature after their first hibernation. Reproductive seasons last from April through August, and mean clutch sizes of 3.55, 4.25, and 5.07 were determined for Cophosaurus and CaUisaurus from Burro Creek and Rock Valley respectively. Multiple clutches were probably common among indi- viduals of both species, but evidence for this at Rock Valley was found only in larger and presvmiably older adults. Also, the reproduc- tive season is probably terminated two to three weeks earlier in this northern population. Mean egg size of both species of lizards and clutch size/body weight ratios o{Cophosaurus were determined to be smaller than reported previouslv from other populations (Vitt 1977, Ballinger et al. 1972). The male reproductive cycles of both spe- cies were found to be similar to those previ- ously reported. However, corpora adiposa of both male and female CaUisaurus from Rock Valley remained relatively large throughout the summer, presumably because of abun- dant food at that locality in 1973. The food habits of both Cophosaurus and CaUisaurus at Burro Creek are similar, but they are probably greatly influenced by spo- radic and episodic availability. Both lizards are highly insectivorous with Orthoptera be- ing the staple food during the summer months. Differences between preference of macro- habitat and microhabitat were observed, Cal- Usaurus preferring sandy open areas and Cophosaurus preferring the presence of some rocks and boulders. Both lizards maintained similar daily activity patterns. CaUisaurus may initiate activity earlier in the day than Cophosaurus, but some Cophosaurus tend to remain active throughout the day. Cophosau- rus has a more pronounced activity period in the evening than was observed for CaUisau- rus. Temperature relationships are very simi- lar for the two species. Niche overlap for the two populations at Burro Creek was calculated at 0.71, 0.57, 0.86, and 0.88 at the levels of macrohabitat, 184 Great Basin Naturalist Vol. 47, No. 1 Table 7. Habitat preferences of Cophosaunis and Callisaurus at Burro Creek, based upon plant associations and soil type. Figures are frequency of encounters in percent. Table 8. Frequency of collections oiCophosaurus and Callisaurus at 12 daily time intervals at Burro Creek. Cophosaurus Callisaurus Plant association Cophosaurus Callisaurus Riparian 77.9 40.5 Arrovo 14.2 56.9 Acacia — 1.7 Paloverde-Sahuaro 7.9 0.9 Totals 100.0 100.0 Soil/substrate type Sand 24.8 72.0 Gravel 6.2 8.8 Boulders 69.0 19.2 Totals 100.0 100.0 microhabitat, time of activity, and food habits respectively. The values of microhabitat and temporal overlap are very similar to the mean values for North American lizards calculated by Pianka (1973) at 0.55 and 0.86 respectively. But niche overlap at the trophic level is much higher at Burro Creek at 0.88 compared to Pianka's mean value of 0.49. It is probable that the productive environs associated with the riparian habitat in an otherwise desert com- munity are responsible for the coexistence of these two similar sand lizards at Burro Creek. Acknowledgments We thank A. E. Bridges, B. G. Maza, P. J. Medica, M. Skivington, and K. Sullivan for assistance in the field. We acknowledge a grant from the Grants-in-aid of Research Committee of the Society of Sigma Xi to P. A. Medica for travel and supplies. The portion of this study done at Rock Valley was supported in part by Contract DE-AC03-76-SF00012 between the U.S. Department of Energy and the University of California, and the Interna- tional Biological Program/Desert Biome (Na- tional Science Foundation Grant BG32139). We thank the Civil Effects Test Organization Office and A. Marrow at the Nevada Test Site for their support. We also wish to thank J. R. Dixon, the late W. W. Milstead, and W. W. Tanner for their encouragement to begin this study. Literature Cited Ballinger, R E , E D. Tylek. and D W Tinkle 1972. Reproductive ecology of a west Texas population of the greater earless lizard, Cophosaurus tex- anus. Amer. Midi. Nat. 88(2): 419-428. Time Percent Percent interval N frequency N frequency 0700-07.59 0 0.0 3 2.3 0800-0859 4 3.5 10 7.8 0900-0959 13 11.3 39 .30.2 1000-1059 29 25.2 34 26.4 1100-11.59 22 19.1 20 15.5 1200-12.59 18 15.7 10 7.8 1300-1.3.59 5 4.3 6 4.7 1400-14.59 2 1.7 0 0.0 1500-1.559 3 2.6 0 0.0 1600-16.59 2 1.7 0 0.0 1700-1759 10 8.7 1 0.8 1800-18.59 7 6.1 6 4.7 Totals 115 99.9 129 100.2 Clarke, R. F. 1965. An ethological study of the iguanid lizard genera Callisaurus, Cophosaurus, and Hol- hrookia. Emporia State Research Studies. Vol. 1.3(4). 66 pp. Engeling, G. a. 1972. Ecology of the iguanid lizard Cophosaurus texanus (Troschel) in Comal County, Texas. Unpublished thesis, Southwest Texas State University, San Marcos. 108 pp. FiTcn, H S 1985. Variation in clutch and litter size in New World reptiles. Kansas University Mus. Nat. Hist., Misc. Publ. No. 76. 76 pp. HowLAND, J M 1984. The reproductive biology of the iguanid lizard Cophosaurus texanus in Big Bend National Park, Texas. Abstract. Page 133 iti A.S.I.H., H.L., S.S.A.R. Meeting, Prog, and Abst. HuLSE, A C 1973. Herpetofauna of the Fort Apache Indian Reservation, east central Arizona. J. Herp. 7(3): 275-282. Johnson. C 1960. Reproductive cycle in females of the greater earless lizard, Holbroohia texana. Copeia 1960(4): 297-,300. Kay, F R 1972. Activity patterns of Callisaurus dra- conoidcs at Saratoga Springs, Death Valley, Cali- fornia, Ilerpetologica 28(1): 65-69. Kay, F R , B W. Miller, and C, L Miller 1970. Food habits and reproduction of Callisaurus dra- conoides in Death Vallev, California. Herpetolog- ica 26(4); 431-436. Medica. P A., and B G Maza. 1974. Geographic distri- bution: Masticophis bilineatus bilineatus. SSAR Herp. Rev. .5(3): 70. Medica, P A , and F B Ti'rner 1976. Reproduction by Ufa stanshtiriana (Reptilia, Lacertilia, Iguanidae) in southern Nevada. J. Herp. 10(2): 123-128. Medica, P A., and L. J Vitt 1974. Geographic distribu- tion: Eumeces gilherti arizonensis. SSAR Herp. Rev. .5(3): 69-70. MUTH, A 1977a. Body temperature and associated pos- tures of the zebra-tailed lizard, Callisaurus dra- conoides. Copeia 1977(1): 122-125. 1977b. Thermoregulatory postures and orienta- tion to the sun: a mechanistic evaluation for the zebra-tailed lizard, Callisaurus draconoides. Copeia 1977(4): 710-720. April 1987 Smith etal.: Sand Lizard EcoLocn' 185 Pack, H. J 1923. Food habits of Callisaurus vcntralis ventralis (Hallowell). Proc. Biol. Soc. Washington 36: 79-82. Packard, G. C, and M. J. Packard. 1970. Eccritic tem- peratures of zebra-tailed lizards on the Mojave Desert. Herpetologica 26(2): 16S-172. Parker, W. S. 1973. Notes on reproduction of some lizards from Arizona, New Mexico, Texas and Utah. Herpetologica 29(3): 258-264. Peters, J. A 1951. Studies on the hzard Holhrookia tex- ana (Troschel) with description of two new subspe- cies. Occ. Pap. Mus. Zool., Univ. Michigan No. 537. 20 pp. PlANKA, E. R. 1973. The structure of lizard communities. Ann. Rev. Ecol. Syst. 4: 53-74. 1974. Niche overlap and diffuse competition. Proc. Nat. Acad. Sci. U.S.A. 71(5): 2141-2145. PiANKA, E. R., AND W S. Parker 1972. Ecology of the iguanid lizard Callisaurus draconoides. Copeia 1972(3): 493-508. Sanborn. S. R. 1972. Food habits oi Sauroiualus obesus obesus on the Nevada Test Site. J. Herp. 6(2): 142-144. Shrank, G D , and R E Ballinger 1973. Male repro- ductive cycles in two species of lizard (Cophosau- rus texanus and Cnemidophorus ^idaris). Her- petologica 29(3): 289-293. Smith, D D , and P A Medica 1973. Geographic distri- bution; Thamnophis ajrtopsis cyrtopsis. SSAR HISS News J. 1(5): 153. Stebbins, R C 1966. A field guide to western reptiles and amphibians. Houghton Mifflin Co., Boston. 279 pp. Tanner, VV W . and J E Krugh 1975. Ecology of the zebra-tailed lizard Callisaurus draconoides at the Nevada Test Site. Herpetologica 31(3): 302- 316. Tinkle, D W 1969. The concept of reproductive effort and its relation to the evolution of life histories of lizards. Amer. Nat. 103: 501-516. Tinkle, D W., H. M Wilbur, and S. G. Tilley. 1970. Evolutionary strategies in lizard reproduction. Evolution 24: 55-74. ViTT. L. J 1977. Observations on clutch and egg size and evidence for multiple clutches in lizards of south- western United States. Herpetologica 33(3): 333-338. ViTT, L J., AND R D Ohmart 1977. Ecology and repro- duction of lower Colorado River lizards: I. Cal- lisaurus draconoides (Iguanidae). Herpetologica 33(2): 214-222. Whitford, W G , AND F M Creusere 1977. Seasonal and yearly fluctuations in Chihuahuan Desert lizard communities. Herpetologica 33(1); 54-65. ZOOGEOGRAPHY OF GREAT BASIN BUTTERFLIES: PATTERNS OF DISTRIBUTION AND DIFFERENTIATION George T. Austin and Dennis D. Murphy" Abstract. — The butterflies of the Great Basin exhibit general patterns of distriljution and speciation similar to those found for other taxa, particularly birds. Two major centers of infraspecific differentiation and coinciding distribution limits of taxa are identified, each with three subregions. Great Basin butterflies are characterized by pallidity and substantial endemism below the species level. The Great Basin of western North America is a huge area, nearly 520,000 square kilome- ters, of largely internal drainage between the Rocky Mountains to the east and the Sierra Nevada to the west. It includes Utah west of the Wasatch Plateau, extreme southwestern Idaho and southeastern Oregon, California east of the Sierra Nevada, and nearly all of Nevada (Fig. 1). Elevations range from l,000-m lowlands dominated by sagebrush {Artemisia) and saltbush {Atriplex) to numer- ous, mostly north-south oriented mountain ranges which may exceed 3,000 m. These mountain ranges, most of which are forested only at the higher elevations, constitute is- lands of boreal habitat. Lowland wet areas are similarly islandlike. The area is largely unin- habited by humans and is relatively undis- turbed except for livestock grazing which has had substantial impact on the composition of the vegetation, especially at lower elevations (e.g., Rogers 1982, Thomas 1983). Studies of the distribution and biogeogra- phy of Great Basin biota have dealt largely with vertebrates (e.g., Behle 1963, 1978, Brown 1971, 1978, Grayson 1982, 1983, John- son 1975, 1978, Smith 1978) and plants (e.g., Billings 1978, Harper et al. 1978). Here we present information on the distribution of Great Basin butterflies, paying particular at- tention to the distributional limits of species, subspecies, and well-differentiated segre- gates, and to centers of infraspecific differenti- ation. Additionally, we discuss the role of "is- land" effects in shaping local species richness. Materials and Methods Distribution maps for butterfly taxa and other distinct phenotypes occurring within and on the margins of the Great Basin were constructed from a variety of sources. Nevada data are drawn primarily from the collections and field notes at the Nevada State Museum, Carson City, the senior author's personal col- lection, and collections made by the Center for Conservation Biology at Stanford Univer- sity. Eastern California data were obtained from the notes and collections of a number of private collectors. Southern Oregon records are from Dornfeld (1980), and Rocky Moun- tain and eastern Great Basin records are from Ferris and Brown (1981). Some Sierra Nevada data were obtained from Shapiro et al. (1979) and the collections of the Nevada State Mu- seum. Numerous other literature sources were consulted. The maps thus prepared were examined to determine patterns of distribution within the Great Basin and adjacent areas. Attention was paid to the absence or presence of species within the Great Basin and the extent of their apparent distributions and differentiation in the Great Basin. Taxa and Distribution The 155 butterfly species occurring in the Great Basin include some 240 subspecies and well-differentiated segregates. More than half the species are geographically polytypic in this and adjacent regions, including the Rocky Nevada State Museum and Historical Society, 700 Twin Lakes Drive, Las Vegas, Nevada 89107. Department of Biological Sciences, Stanford University, Stanford, California 9430.5. 186 April 1987 Austin, Murphv: Great Basin Butterflies 187 OREGON WARNER SUBREGION [ NEVADA IDAHO f Jarbidge Mountains I Independence Mountains CENTRAL SUBREGION Virginia [/ ^ Range ^ , Pine Nut 3|l jl Mountains Wassuk ?V,^ Range INYOV^ SUBREGION ^^ JARBIDGE SUBREGION •KEast Humboldt Mountains ^ i IF Ruby Mountains A Snake Range . TOIYABE \ SUBREGION White Mountains ^-1 \ ■• ..•■•■■' SNAKE SUBREGION ARIZONA MOJAVE SUBREGION Spring Range ^ \ / Fig. 1. The Great Basin showing subregions and locations mentioned in the text. Mountains and Sierra Nevada. No species are endemic to the Great Basin, consistent with previous findings for birds (Behle 1963). About 50 subspecies and other well-differen- tiated infraspecific segregates (distinct groups of phenotypically similar, but unnamed, pop- ulations) of butterflies, however, are re- stricted to the Great Basin. A number of addi- tional groups of populations within the region show some measurable diflerentiation. The distributions of these taxa and segregates by geographic affinities are summarized in Table 1. Nearly 90% of all Great Basin butterfly spe- cies are also found in the Rockv Mountains. 188 Great Basin Naturalist Vol. 47, No. 2 Table 1. AflFinities of the Great Basin butterfly fauna. Taxa include subspecies and distinct unnamed segre- gates. Species Taxa Sierra Nevada 8 (5.2%) 35 (14.5%) Rockv Mountain 30 (19.3%) 67 (27.8%) Widespread (including Sierra Nevada and Rockv Mountains) 99 (63.8%) 48 (19.9%) Endemic 0 (0.0%) 52 (21.6%) Southern 15 (9.7%) 29 (12.0%) Northern 3 (1.9%) 10 (4.1%) Total Number 155 241 Only about two-thirds of the Great Basin but- terfly species occur in the Sierra Nevada. When considering truly widespread Great Basin taxa as opposed to those occurring merely on the margins, Great Basin butter- flies shared with the Rocky Mountains out- number those shared with the Sieira Nevada by about three to one. Great Basin butterflies are made up of sev- eral distinct groups: 1. A large number of relatively widespread species which occur in the Great Basin as endemic subspecies or segregates (many of which represent the species' most pallid phe- notype). This in itself identifies the Great Basin as a distinct region of differentiation for butterflies. 2. A group of widespread species which occur throughout much of the western portion of the continent. The majority of these species show little or no regional differentiation. 3. A number of desert taxa extending into the Great Basin from the south, reaching their northern limit there and either occurring only along the southern fringe of the basin or rang- ing further north as permanent populations, seasonal populations, or stray individuals. Many other species occur just south of the Great Basin in extreme southern Nevada and southwestern Utah (e.g., Austin and Austin 1980). 4. And, finally, there are a few butterflies of mainly northern affinity that range south into the Great Basin. Nearly all of these are limited to the northern portion of the Great Basin. The Great Basin butterfly fauna is charac- terized not only by the presence of numerous endemic phenotypes but by the restricted dis- tribution or conspicuous absence of certain taxa. The borders of the Great Basin addition- Table 2. Widespread Rocky Mountain and Sierra Ne- vada butterfly species absent or nearly so from the Great Basin. Eparg,ijreus clams Thon/bcs pylades Thonjbcs mexicana Enjnnis pacuvius Pyr»or»i()n!« fl/toHi.S' and S. ;/i. mormonia Table 4 eontinui'd. 40. Euphydryas editha lehmani and £. c. monoensis 41. Cocnonymp}ui ochracea mono and C. ochraceae b rendu AlLOCHRONIC SYMP.\TRY BETW EEN REPRESENT.\TI\'ES of DI- VERGENT SUBSPECIES: 42. Euphilotcs battoides baucri and E. b. glaucon 43. Euphilotcs enoptes ancilla and E. e. enoptes pairs are narrowly synipatric, or nearly so, with little or no hybridization or intergrada- tion in this zone. The closely related Chlosyne palla and C. acastus appear to be sympatric at the eastern base of the Sierra Nevada and in the Pine Nut and Virginia mountains without hybridizing. Anthochahs sara thoosa and A. s. Stella co-occur in extreme western Nevada but with little intergradation (these, in fact, may be different species). Another species pair, Limenitis wcidemcijehi and L. lorquini, hybridizes in a very narrow zone just east of the Sierra Nevada (Perkins and Perkins 1967) with extensions northward into Idaho and southwestern Alberta. Yet another pair, Mi- toura siva and M. nelsoni, have long been considered distinct species. They, however, hybridize in a broad region in the western Great Basin and hence may be one species. Isolated high-elevation populations of at least two species, Polites sabuleti and Phy- ciodcs campestris, exist in the Sierra Nevada bounded on both the east and west by more widespread, lower-elevation subspecies. Two other species, Euphydnjas editha and E. chalcedona, exist as a series of elevational sub- species (perhaps ecotypes) on the west slope to the crest of the Sierra Nevada and as a single middle-elevation subspecies on the east slope and into the western Great Basin. Numerous Great Basin subspecies (or segre- gates) are "replaced" by Sierra Nevadan taxa between the western portion of the Great Basin and the crest of the Sierra Nevada (Table 4). There is usually narrow elevational allopatry and/or allochrony (imposed by ele- vational differences in phenology) between these phenotypes, but intergradation occurs in some. Furthermore, both Euphilotcs enoptes and E. battoides are represented by sympatric allochronic "populations." These distinct univoltine populations fly at single locations at different times of the year and thus thus are reproductiveK' isolated temporally (hence should constitute "allochronic species"). 194 Great Basin Naturalist Vol. 47, No. 2 Table 5. Pairs of butterfly taxa showing various specia- tion phenomena in the northeastern Great Basin (most widespread Great Basin taxon hsted first). Narrow zone of sympathy between closely related SPECIES without HYBRIDIZATION: 1. Euphydryas anicia wheeleri and E. colon nevadensis Narrow zone of sympatry and interspecific hybridiza- tion: 2. Euphilotes enoptes ancilla and £. hattoides ^laitcon 3. Coenonynipha ochracea hrenda and C. ampelos elko Narrow (usually) zone of sympatry and intergrada- tion between representatives of divergent subspe- CIES: 4. Colias alexandra edwardsii and C. a. astraea 5. Plehejus acmon acmon and P. a. lutzi 6. Speyerianokornis apacheana iin(\S. n. nokomis 7. Speyeria egleis titahensis and S. e. linda 8. Phyciodes campestris campestris and P. c. camillus 9. Euphydryas editha lehmani and E. e. Iwtchinsi 10. Limenitis archippus lahontani and L. a. archippus Narrow zone of allop.atry between closely related SPECIES: 11. Papilio bairdii and P. oregonius (may be conspecific) Narrow zone of allopathy between representatives OF divergent SUBSPECIES; 12. Anthocharis sara thoosa and A. sara hrowningi 13. Satyrium sylviniis seg. and S. s. putnaini 14. Euphilotes rita pallescens and E. r. mattunii 15. Speyeria atlantis greyi and S. atlantis elko Broad zone of allopathy between representatives of dinergent subspecies: 16. Satyrium saepium provo and S. saepium seg. 17. Lycaena nivalis browni and L. n. nivalis Disjunctions between distinct species and between subspecies or segregates within the same species are manifest in both narrow and wide zones of allopatry in the Sierra Nevada Zone (Table 4). Some of these "gaps" are just a few miles wide, such as between the eastern- most margin of the Sierra Nevada and the westernmost Great Basin mountain ranges. But other gaps include much of the broad expanse between the eastern Sierra Nevada and the mountains of central Nevada. Many species that range continuously across the re- gion north of the Great Basin are also absent in this same broad area. Note that many gaps in distribution more or less coincide with re- gions of intergradation and of overlap be- tween pairs of taxa discussed above. Northeastern Nevada Zone Another area of substantial apparent incipi- ent speciation in the Great Basin is the north- eastern portion of Nevada (Fig. 2). This area should probably include northwestern Utah, Table 6. Pairs of butterflies taxa showing various spe- ciation phenomena in central (C) and eastern (E) Great Basin (the most widespread Great Basin taxon is Hsted first). Narrow zone of sympathy and interspecific hybridiza- tion: 1. Plehejus acmon texanus and P. htpini lupini (C) Narrow zone of symp.\try and intergrad.\tion be- tween REPRESENT.ATIVESOF divergent SUBSPECIES: 2. Pontia sisymbrii elivata and P. sisymbrii seg. (E, C) 3. Satyrium behrii crossii and S. b. behrii (C) 4. Cehistrina ladon echo and C. /. cinerea (G) 5. Glaucopsyche piasus nevada and G. piasus daunia (E) 6. Plebejus acmon texanus and P. a. acmon (G) 7. Speyeria zerene gunderi and S. ~. platina (E) 8. Phyciodes campestris campestris and P. c. camillus iC) 9. Limenitis wcidemeyerii latifascia and L. ic. angusti- fascia (E) Narrow zone of allopathy between hepresentatin'Es OF divergent SUBSPECIES: 10. Lycaena arota virginiensis and L. a. schellhachi (E) 11. Euphilotes battoides baueri and E. battoides seg. or £. battoides nr. bernadino (C) 12. Euphilotes enoptes ancilla and E. enoptes seg. (G) 13. Plebejus saepiohis saepiohis and P. s. gertschi (E) (elevational) 14. Euphydryas editha lehmani and £. e. koreti (E, G) (elevational) 1.5. Neominois ridingsii stretchii and N. r. dionysus (G) southern Idaho, and southeastern Oregon, but for these latter areas few pertinent data exist. Information does exist for much of Elko and Humboldt counties and northern Eureka and Lander counties in Nevada. This area is considerably smaller in extent and lacks the abrupt topographical and ecological disconti- nuity of the Sierra Nevada-Great Basin inter- face. Nonetheless, some combination of fac- tors there promotes diflferentiation and replacement. The region also marks the west- ern or southernmost extent of the distribu- tions of many species in the Great Basin (see below). As in the Sierra Nevada Zone, there are replacements (specific and subspecific) with or without hybridization or intergradation and some, mostly narrow, allopatries (Table 5). While the zone of interaction along the Sierra Nevada is east/west in orientation, that in northeastern Nevada is more complicated (Eig. 2). The majority of interactions there involve east/west replacements of Rocky Mountain taxa with those of the Great Basin or Sierra Nevada. There are, however, several April 1987 Austin, Murphy: Great Basin Butterflies 195 Table 7. Pairs of butterfly taxa showing various specia- tion phenomena at the transition Ix'tween the Great Basin and Mojave Desert (Great Basin taxon Hsted first). Narrow zone of sympathy and intergradation be- tween representatives of divergent subspecies: 1 . Pyrfius communis communis and P. c. albescens (par- tial elevational allopatr\', possil)l\ different species) 2. Hespcropsis lihija lena and H. /. Uhya 3. Anthocharis cethura cethuni and A. c. pinui 4. Mitoura siva chalcosiva and M. s. rhodope 5. Glaucopsijche hm.damus oro and G. hj^damus seg. (partial elevational allopatry) 6. Euphtjdnjas anicia wheeleri and E. a. idcna 7. Cercyonis sthenele pauhis and C. s. miisoni Narrow zone of allopatry between closely related SPECIES: 8. Chlosyne acastus acastus and C. neutnoc^cui ncu- moegeni Narrow zone of allopatry between representatives OF divergent SUBSPECIES: 9. Polites sabuleti sabuleti and P. s. chusca 10. Papilio indra nevadensis and P. indra n^aiiini or P. indrci seg. 11. Euphilotes battoides baueri and E. b. imn-tini 12. Plebejus melissa melissa and P. mclissa seg. 13. Apodemia monno mormo and P. mornw seg. (partial elevational and seasonal allopatry) Broad zone of allop.\try between closely related SPECIES: 14. chlosyne acastus acastus and C. palla vallismoi-tis Broad zone of allop.-vtry between represent.\ti\'es of divergent subspecies: 15. Plebejus icarioides ardea and P. icarioides seg. 16. Plebejus shasta minnehalui and P. s. charlestonensis 17. Speyeria zerene gunderi or S. ;. malcolmi and S. ;. carol ae 18. Euphydryas anicia wheeleri and E. a. morandi 19. Eiincnitis archippus lahontani and L. a. obsoleta 20. Liinenitis weidemeyerii latifascia and L. w. nevadae north/south replacements of taxa from Oregon or Idaho with generally widespread Great Basin taxa. One subspecies each of both Speyeria e^leis and S. atlantis extends into this zone from the north and another from the east (Austin 1983). Furthermore, intergrada- tion of phenotypes occurs among at least seven other subspecies pairs. For some of these (e.g., Speyeria nokomis, Swisher and Morrison 1969) this blending occurs over a broad area of the eastern Great Basin and northwestern Colorado; for others (e.g., Eu- phydryas editha) the cline is quite narrow. Finally, hybridization apparently occurs be- tween Euphilotes battoides and E. enoptes (Shields 1977) and between the semispecies Coenonympha ampelos and C. ochracea of the C. tullia superspecies complex in this area. Eastern Nevada- Western Utah Zone This region, which includes White Pine and Lincoln counties in Nevada and parts of adja- cent Utah, is a comparatively minor area of speciation and faunal replacement (Table 6, Fig. 2). The apparent subspecific endemics are shown in Table 3. Most phenotypically identifiable replacements consist of Great Basin subspecies or segregate replacing Rocky Mountain subspecies with minor in- tergradation. There is, in addition, some re- placement of desert subspecies or segregates with subspecies or segregates which range widely north of this zone. This portion of the Great Basin is most noteworthy as a northern or western limit of the distributions of a num- ber of taxa (see below). Central Nevada Zone This area includes the central Nevada mountains and valleys and is another compar- atively minor area of interaction among phe- notypes (Table 6, Fig. 2). Many of the interac- tions discussed for the previous two zones extend for varying distances into the Central Nevada Zone. Both east/west and north/south interactions are involved. A particularly inter- esting feature in this zone, and in other areas to the north as well, is the apparent hybridiza- tion between two species of blues, Plebejus acmon and P. lupini (Goodpasture 1973). The zone, in part, forms the eastern edge of a broad gap or zone of allopatry between spe- cies which are present between here and the Sierra Nevada (see above). Mojave Desert-Great Basin Zone This area, including parts of Lincoln, Nye, and Esmeralda counties, Nevada, and Wash- ington County, Utah, is recognized as the northern limit of Mojave Desert plants (Beat- ley 1975, Meyer 1978) and birds (Behle 1978, Johnson 1978), hence the southern limit of the Great Basin. Mammalian and herpetological distributions also support this as a distinct area of biological discontinuity (Hall 1946, Banta 1965a, b). Several butterfly species oc- curring widely in both areas exhibit different phenotypes on either side of this transition, while others intergrade across this area (Table 7, Fig. 2). There is a zone of allopatry for some taxa and segregates between the Great Basin and Mojave Desert, but this zone is generally 196 Great Basin Naturalist Vol. 47, No. 2 Table 8. Rocky Mountain butterfly species extending west to the Sierra Nevada across the Great Basin. Hesperopsis libya Hesperia tineas Colias (ilexandra Lijcaena ruhidus Mitoura siva Speyeria nokomis Chlosync acastus Eiiphydryas anicia Limenitis weidcmeycrii Coenonympha ochracea Neominois ridingsii narrow. Only for Limenitis archippus is there a broad zone of allopatry; several hundred kilometers separate L. a. obsoleta in the Colo- rado River drainage and L. a. lahontani along the Humboldt River. Wasatch Front Zone The interface of the western escarpment of the Rocky Mountains with the Great Basin in central Utah superficially presents topograph- ical and ecological contrasts comparable to that of the Sierra Nevada zone. Nevertheless, faunal replacement in this zone is not as strik- ing as along the western edge of the Great Basin. Some endemic subspecies (or segre- gates) occur in this zone, and there is replace- ment of some Rocky Mountain taxa with those of the Great Basin. A sizable number of Rocky Mountain subspecies as discussed below, however, extend past this area well into the Great Basin. Widespread Great Basin butter- flies such as Hesperia comma harpahis, Pontia sisymbrii elivata, Euchloe hyantis lotta (this taxon may be a species in itself, separate from £. hyantis fide P. A. Opler), Lycaena ruhidus sirius, Plehejus icarioidesfuUa, P. shasta min- nehaha, Speyeria coronis snyderi, and S. cal- lippe harmonia range west from the Wasatch Front across virtually the entire Great Basin, some as far as the east slope of the Sierra Nevada. Distributional Limits Distributional limits of butterflies in the Great Basin and adjacent areas exhibit repeat- ing patterns of particular interest. Some spe- cies, as mentioned, totally avoid the Great Basin, occurring solely at its borders. This overall situation essentially results from four distinct distribution patterns: (1) eastern taxa that occur to the western limits of the Rocky Mountains, (2) extreme western taxa extend- ing no further east than the east slope of the Sierra Nevada, (3) taxa of mainly Rocky Moun- tain affinity that occur to the eastern borders of the Great Basin, then north across Idaho and Oregon and, in numerous cases, south into the Sierra, and (4) southern taxa that oc- cur north to southern Nevada and/or south- western Utah. Other species reach the limits of their ranges somewhere within the Great Basin re- gion. This includes a number of butterfly taxa that enter only the eastern portion of the Great Basin and otherwise possess a distribu- tional pattern like the species in (3) above. The limits of these latter two groups coincide closely with the zone boundaries discussed in the previous section on speciation. Few Sierra Nevada species extend into the Great Basin and only Plehejus hipini, as men- tioned above, for a substantial distance. The remainder occur, for the most part, only in the western Great Basin ranges. Of the two appar- ent endemic species of butterflies in the Sierra Nevada, Hesperia miriamae and Colias hehrii, only H. miriamae extends its distribu- tion into the Great Basin as a phenotypically distinct isolate found solely in the White Mountains. Endemic Sierra Nevada subspe- cies also have made few inroads into the Great Basin. Among the approximately 20 primarily alpine or subalpine taxa, only Plehejus fraukUnii podarce (one record from the Vir- ginia Range) and Pohtes sabuleti tecumseh, Chlosyne w. whitneyi, and Euphydryas editha nuhigena (Sweetwater Mountains) ex- tend east into the Great Basin. The east slope of the Sierra Nevada, in turn, is the western distribution limit of at least 11 Rocky Moun- tain species (Table 8). A number of Rocky Mountain species (some of which also occiu" in the Sierra Nevada) enter the Great Basin only in northeastern Nevada (Table 9). Most of these species have re- stricted Great Basin distributions and occur in both the Sierra and Rocky Mountains. Nu- merous additional species occur as isolates on many of the Great Basin ranges. Three species with primarily southern dis- tributions, Hesperopsis alpheus, Anthocharis cetJiura, PhilotieUa speciosa, occur through- out much of the western Great Basin but not the eastern. Several others extend to the east- April 1987 Austin, Muhfhy: Great Basin Butterflies 197 Table 9. Widespread butterfly species eTiterinti tlie Great Basin only in tlie northeastern portion. Hesperia nevada Parnasshis phocbus Papilio eurijmcdon Pieris napi Lijcacna cupreus Lijcaena dorcas Speyeria ctjhele Spcijcria atlantis Spctjehd inonnonia Phijciodes tharos ern and central regions. None, however, reach northeastern Nevada except as strays or nonpermanent populations. A number of spe- cies reach their northern distributional limits in southern Nevada, south of the Mojave Desert/Great Basin transition (Austin and Austin 1980). Likewise, numerous Great Basin species have their southern distribu- tional limits near that boundary. Nonetheless, more than 10% of the butterfly species in the Spring Mountains in extreme southern Ne- vada are of Great Basin affinity, and several endemic subspecies and segregates in this range appear to be closely related to Great Basin taxa (Austin 1981). This suggests a more extensive southern distribution for much of the Great Basin fauna in the past and agrees with our knowledge of the vicissitudes in Pleistocene climate (e.g., Martin and Mehringer 1965, Wells 1983). Taxa with pri- marily northern distributions (e.g. , alpine Co- lias, Boloria, Erebia, Oeneis), on the other hand, contribute very little in general to the Great Basin fauna. However, three putative "species," Papilio oregonius, Euphydnjas colon, and Coenonympha ampclos (each con- specific with or siblings of more widespread Great Basin species), enter the northeastern region. One, C. ampelos , extends the furthest south, well into western Nevada to the Carson River basin. PALLIDITi At least 20 butterfly species exhibit their most pallid phenotype in the Great Basin (Table 10). An additional three butterfly sub- species groups reach their extreme in pallidity in the region. Linsdale (1938) and Hall (1946) noted a similar phenomenon in Nevada birds and mammals. Seven of the pallid l:)utterfly Tabi.K 10. List and general distribution of Great Basin pallid iiutterfly taxa. Western Great Basin Thonjhi's mcxicana hlanca Euphilotes rita svg. Speyeria zerene tmdcolmi ("zerene" ssp. group) Speyerid callippe nevadensis ("nevadensis" ssp. group) Coenonympha ochracca mono Cercyoni.s pc^ala steplwnsi Neominois ridingsii sag. Central Great Basin Polites sabideti seg. Speyeria egleis toiyahe Cercyonis oetus pallescens Northeastern Great Basin Ochlodes sylvanoidcs honncvilla Lycaena editha nevadensis Speyeria atlantis greyi Speyeria atlantis elko {"irene" ssp. group) Speyeria mormonia artonis Pliyciodes campestris seg. Coenonymplia antpelos elko General Great Basin Hesperia uncas lasus Incisalia eryphon seg. Speyeria nokomis apacheana Speyeria zerene ounderi Limenitis nrchippus lahontani Cercyonis sthenele paulus taxa and segregates are restricted to the north- eastern region, seven are in western Nevada, three are in central Nevada, and six are more generally distributed. Some pallid subspecies and segregates are extremely restricted geo- graphically, such as Cercyonis oetus palles- cens, found only in small areas of the Reese River and Big Smoky valleys, and an unde- scribed Euphilotes rita segregate, found only at Sand Mountain east of Fallon. White alka- line or other pale soil was suggested as the key to predator-mediated selection for a pale ground color for many of these species (Emmel and Emmel 1969, 1971, Emmel and Mattoon 1972, Wielgus and Wielgus 1974). This may be true for some nondesert species as well (e.g., Hovanitz 1940, 1941, Bagdonas and Harrington 1979) and is supported by the presence of extreme dark phenotypes of some species in dark-background, marshy areas of the Great Basin (e.g., Polites sabuleti in east- ern Nevada). The presence of pallid pheno- types in much of the Great Basin, of course, is also consistent with Watts (1968) findings as- sociating lighter basal wing color with warmer thermal regimes. 198 Great Basin Naturalist Vol. 47, No. 2 Discussion The Great Basin butterfly fauna substanti- ates many zoogeographic generalities previ- ously drawn for other taxonomic groups, par- ticularly birds, in this region. Foremost, there is a general impoverishment of species rich- ness inward from the peripheries, especially from the Rocky Mountains westward. This would be predicted from the similar distribu- tion patterns recorded for plants (Billings 1978, Harper et al. 1978), in light of the close association of butterflies and their larval host plants. Nevertheless, suitable habitat (includ- ing adequate specific host plant availability) appears to exist for many butterfly species missing from portions of the Great Basin. This impoverishment, as well as the previ- ously noted endemism, presence of "relict" populations, and indications of recent extinc- tions (Austin 1985), is consistent with an "is- land effect" (MacArthur and Wilson 1967). This situation in the Great Basin largely arises from the sequestering of biotic diversity in comparatively small and isolated patches of montane habitat surrounded by sagebrush- dominated desert. The insular biogeography, particularly area effects and immigration- extinction dynamics, of the montane Great Basin mammals, birds, and butterflies has been discussed previouslv (Brown 1971, 1978, Austin 1981, Murphy and Wilcox 1985, Murphy et al. 1986, Wilcox et al. 1986). The same relationships are seen in fish and land snails (Smith 1978, Pratt 1985). Montane or boreal biotic elements in the Great Basin appear to exhibit relictual distri- butions. This is best substantiated by mam- malian distributions since they include both recent (Brown 1971, 1978) and fossil (Grayson 1982, 1983) evidence. These data indicate that present-day boreal mammalian faunas are not at equilibrium (that is, they lack balanced rates of extinction and of colonization) but are largely the result of range constriction and subsequent extinction (without recoloniza- tion) of a once widespread Pleistocene fauna. Fossil evidence from the central Great Basin reinforces the popular view that boreal habi- tat, extensive in the Pleistocene, withdrew northward and contracted toward montane summits. Grayson (1983) reports the fossil presence of the vole Phenacomys cf inter- medius in the Toquima Range. This species is now restricted to areas far north and west of that range. Furthermore, pika (Ochotona princeps) remains have been recovered more than 1,000 m lower in elevation than known at present. Grayson (1982) implies that: (1) bo- real mammals were widely distributed across the lowlands, (2) extinction led to the present absence of certain species on certain montane islands, (3) certain species became extinct on all montane islands, and (4) there was no Holocene recolonization. For butterflies, we have only present-day distributions to examine. Butterflies, like birds, are considerably more vagile than most mammals; thus, it is not surprising that they show less-dramatic effects of island size and isolation. That butterflies are more mobile than mammals (but less so than birds) is re- flected in the comparatively low slope associ- ated with the species-area curves for butter- flies from Great Basin mountain ranges (Murphy et al. 1986, Wilcox et al. 1986). Hence, rates of interrange (interisland) dis- persal should be higher, and recolonization after extinction more frequent, in butterflies than in mammals. Nonetheless, a significant area effect is found for butterflies. But, sup- porting the notion that rates of extinction ex- ceed that of colonization in at least some but- terfly species, Wilcox et al. (1986) have shown that the numbers of "sedentary" butterfly species are better correlated with area than are "vagile butterflies. Less-mobile taxa (e.g., montane land snails and lowland fish) exhibit an even greater effect of isolation and extinction in this region (Smith 1978, Pratt 1985). Note that islandlike effects of area and isola- tion are not restricted to montane or boreal elements in the Great Basin. Lowland ripar- ian butterflies appear to be equally isolated, and the faunas of these communities exhibit similar effects (Austin 1985). Riparian butter- fly species richness decreases from the Golo- rado River Valley northward (upstream) into the central Great Basin. In the northern Great Basin, species richness decreases from the relatively rich upper river valleys (Humboldt, Garson, Walker) downstream toward the cen- tral Great Basin. Given the high number of phenetically dis- tinct, geographically restricted endemic but- terfly subspecies and segregates, it is of inter- est to note patterns of differentiation in other April 1987 Austin, Murphy: Great Basin Butterflies 199 taxa within the Great Basin. Speciation in all taxa is most striking along the western and northeastern edges of the Great Basin. Bnt, differentiation certainly is not limited to these areas. Stutz (1978), for instance, identified several rich evolutionary sites for Atriplcx in the Great Basin, similar to those found for birds (Behle 1963, Johnson 1978), and corre- sponding to centers of differentiation and lim- its of distributions of plants in the Great Basin as outlined by Cronquist et al. (1972). These studies and our butterfly data clearly indicate the existence of distinct areas of interaction and spe- ciation within the whole of the Great Basin. As we mentioned in several sections above, butterflies and birds are extremely similar in their patterns of distribution and differentia- tion within the Great Basin. This similarity also extends to other taxa including reptiles and amphibians (Stebbins 1954) and mammals (Hall 1946, Hall and Kelson 1959). Am- hijstoma tigrinum and Bufo woodhousei are Rocky Mountain amphibian species not oc- curring in the Great Basin but extending west along its northern margin. A far-western Great Basin subspecies of Bufo boreas re- places a widespread interior subspecies in the western Great Basin, and an isolated subspe- cies occurs in the Inyo Region. Reptiles that avoid the Great Basin but occur along its bor- ders include Phnjnosoma douglasii and Thamnophis sirtalis, the latter occurring in both the Rocky Mountains and the Sierra Ne- vada. Subspecific intergradation occurs along the Sierra Nevada-Great Basin interface {Sceloporus graciosus, S. occidentalis , Thamnophis elegans, Crotahis viridus) and near the Mojave Desert-Great Basin transi- tion {Callisaurus draconoides, Phnjnosoma platyrhinos, Uta stansburiana). Extension of primarily southern species northward in the western Great Basin east of the Sierra Nevada is relatively common. Tanner (1978) com- mented on the absence in the Great Basin of expected montane species or of endemic spe- cies of amphibians and reptiles. Numerous examples of similar phenomena exist among mammals. Species such as Lepus americanus, Eutamias amoenus, Tamiasciu- rns douglasii, and Maries americana are found in both the Rocky Mountains and Sierra Nevada but not the Great Basin. Others ex- tend northward from the southern deserts onlv in the western Great Basin. An interface exists between subspecies in the extreme southern or extreme western Great Basin for several mammal species. Subspecific en- demics largely follow the patterns described above for butterflies. One species, Mi- crodipodops pallidus, in fact, is a Great Basin endemic. The distributions of mammals at the species level (Hagmeier 1966) are consistent with our butterfly data; and more fine- grained, below-the-species-level studies may well further strengthen this comparison with our findings. Acknowledgments Numerous people made their records and/ or specimens of Great Basin butterflies avail- able to us: R. Albright, D. E. Allen, R. Bailowitz, D. L. Bauer, J. Brock, F. M. Brown, J. M. Burns, C. Gallaghan, H. Clench, J. T. Cooper, C. Crunden, T. E. Dimock, D. Eff", J. F. Emmel, T. C. Emmel, C. D. Ferris, C. F. Gillette, R. E. Gray, L. P. Grey, D. Guiliani, C. Hageman, K. Hansen, G. Harjes, C. Henne, P. J. Herlan, J. Lane, R. L. Langston, C. S. Lawson, A. Ludke, W. W. McGuire, C. D. MacNeifl, J. Masters, S. O. Mattoon, D. MuUins, J. S. Nordin, P. A. Opler, E. M. Perkins, Jr., A. Pinzl, F. W. and J. D. Preston, R. Robertson, K. Roever, R. C. Rosche, R. W. Rust, F. Ryser, P. and S. Sav- age, J. A. Scott, C. Sekerman, O. E. Sette, A. Shapiro, A. O. Shields, D. Shillingburg, R. Skalski, M. Smith, N. J. Smith, R. E. Stan- ford, G. B. Straley, W. Swisher, K. B. Tid- well, J. W. Tilden, D. Thomas, W. Whaley, R. E. Wells, B. A. Wilcox, and D. Young. We are grateful to all. We thank the curators of various collections who made specimens available for examination: F. H. Rindge (American Museum of Natural History), L. D. and J. Y. Miller (Allyn Museum of Entomol- ogy), J. E. Rawlins and C. W. Young (Carnegie Museum of Natural History), J. P. Donahue (Los Angeles County Museum), C. Murvosh (University of Nevada, Las Vegas), F. Ryser (University of Nevada, Reno), and J. Burns, C. F. G. Clarke, and R. K. Robbins (National Museum of Natural History). We also thank S. R. Naegle, P. A. Opler, J. A. Scott, A. M. Shapiro, R. E. Stanford, and B. A. Wilcox for helpful comments on drafts of the manuscript, and P. Church for typing earlv drafts. 200 Great Basin Naturalist Vol. 47, No. 2 Funding for some survey work on which this discussion was based was provided by grant DAR 8022413 from the National Science Foundation. The junior author has been sup- ported by a grant from the Koret Foundation of San Francisco. Literature Cited Austin, G T 1981. The montane butterfly fauna of the Spring Range, Nevada. J. Lepid. Soc. .35; 66-74. 1983. A new subspecies of Speijeria atlantis (Ed- wards) (Nymphahdae) from the Great Basin of Nevada. J.' Lepid. Soc. 37: 244-248. 1985. Lowland riparian butterflies of the Great Basin and associated areas. J. Res. Lepid. 24: 117-131. Austin, G T., and A T Austin 1980. Butterflies of Clark County, Nevada. J. Res. Lepid. 19: 1-63. Bagdonas, K., and M Harrington 1979. Variant adap- tations in moths in Grouse Canvon, Utah. News Lepid. Soc. 1979(5): 6 (abstract).' Banta, B H. 1965a. A distributional check list of the recent reptiles inhabiting the state of Nevada. Occ. Pap. Biol. Soc. Nevada, No. 5. 1965b. A distributional check list of the recent amphibians inhabiting the state of Nevada. Occ. Pap. Biol. Soc. Nevada, No. 7. Beatley, J. G. 1975. Glimates and vegetation pattern across the Mojave/Great Basin Desert transition of southern Nevada. Amer. Midi. Nat. 93: 53-70. Behle, W H. 1963. Avifaunistic analysis of the Great Basin region of North America. Proc. 13th Intern. OrnithoL Gongr.: 1168-llSl. 1978. Avian biogeography of the Great Basin and intermountain region. Great Basin Nat. Mem. 2: 55-80. Billings, W. D. 1978. Alpine phytogeography across the Great Basin. Great Basin IMat. Mem. 2: 105-117. Brown, J. H. 1971. Mammals on mountaintops: nonequi- librium insular biogeography. Amer. Nat. 105: 467-478. 1978. The theory of insular biogeography and the distribution of boreal birds and mammals. Great Basin Nat. Mem. 2: 209-227. Gronquist, a, A. M. Holmgren N H Holmgren, and J. L Reveal. 1972. Intermountain flora, vascular plants of the intermountain west, U.S.A. Vol. 1. Hafner Publ. Co., New York. Dornfeld, E. J 1980. The buttei-flies of Oregon. Timber Press, Forest Grove, Oregon. Emmel.T. G.andJ. F Emmel. 1969. A new subspecies of the Cercyonis meadi group (Satyridae). J. Lepid. Soc. 23: 161-164. 1971. An extraordinary new subspecies oiCercij- onis oetus from central Nevada (Lepidoptera, Satyridae). Pan-Pacific Entomol. 47: 1,55-157. 1973. The butterflies of southern California. Nat. Hist. Mus., Los Angeles Co., Sci. Series 26. Emmel, T. G, and S O. Mattoon. 1972. Cerctjonis pe- gala blanca, a "missing type" in the evolution of the genus Ccrci/oru.s(Satvridae). J. Lepid. Soc. 26: 140-149. Ferris, C. D., and F. M. Brown. 1981. Butterflies of the Rocky Mountain states. University of Oklahoma Press, Norman. Goodpasture, C. 1973. Biology and systematics of the Plebejus (Icaricia) acmon group (Lepidoptera: Ly- caenidae). I. Review of the group. J. Kansas Ento- mol. Soc. 46: 468-485. Grayson, D K. 1982. Toward a history of Great Basin mammals during the past 15,000 years. Pages 82-101 in D. B. Madsen and J. F. O'Gonnell, eds., Man and environment in the Great Basin. Soc. Amer. Archaeol. Papers, No. 2. 1983. Paleontology of Gatecliff Shelter— small mammals. Chapter 6 in D. H. Thomas, J. O. Davis, D. K. Grayson, W. N. Melhorn, T. Thomas, and D. Tre.xler, The archaeology of Mon- itor Valley. 2. GatecliffShelter. Anthropol. Papers Amer. Mus. Nat. Hist., Vol. 59. Grey, L P 1972. Notes on Speijeria zerene populations in Modoc Co. , California. News Lepid. Soc. 1972(6): 2. Grey, L. P., and A. H. Moeck. 1962. Notes on overlap- ping subspecies. I. An example in Speijeria zerene (Nymphahdae). J. Lepid. Soc. 16: 81-97. H.agemeier, E M 1966. A numerical analysis of the dis- tributional patterns of North American mammals. II. Re-evaluation of the provinces. Svst. Zool. 15: 279-299. Hall. E R 1946. Mammals of Nevada. University of California Press, Los Angeles. Hall, E R , and K. R Kelson. 1959. The mammals of North America. 2 vols. Ronald Press, New York. Harper, K T , D C Freeman, W K. Ostler, and L. G. Klikoff. 1978. The flora of Great Basin mountain ranges: diversity, sources, and dispersal ecology. Great Basin Nat. Mem. 2: 81-103. Holdren, C E., and p. R. Ehrlich 1982. Long range dispersal in checkerspot buttei-flies: transplant ex- periments with Eupluidn/as gillctti. Oecologia 50: 125-129. Hovanitz, W 1940. Ecological color variation in a butter- fly and the problem of "protective coloration." Ecology 21:. 371-,380. 1941. Parallel ecogenotypical color variation in buttei-flies. Ecology 22: 259-284. Johnson, N K. 1965. The breeding avifaunas of the Sheep and Spring ranges in southern Nevada. Condor 67: 93-124. 1970. The affinities of the boreal avifauna of the Warner Mountains, California. Occ. Pap. Biol. Soc. Nevada, No. 22. 1975. Controls of number of bird species on mon- tane islands in the Great Basin. Ecologv 29: .545-567. 1978. Patterns of avian geography and speciation in the intermountain region. Great Basin Nat. Mem. 2: 137-1.59. Johnson, N. K , and C B Johnson. 1985. Speciation in sa.\)sudkers {SpJnjrapicus). II. Sympatry and mate preference in S. ruber daf^etti and S. nuchalis. Auk 102: 1-15. LiNSDALE, J. M 1938. Bird life in Nevada with reference to modifications in structure and behavior. Con- dor 40: 137-159. MacArthur, R. H , AND E. O Wilson. 1967. The theory of island biogeography. Princeton University Press, Princeton, New Jersey. April 1987 Austin, Murphy: Great Basin Butterflies 201 Martin, P S., and P. J Mehringer. 1965. Pleistocene pollen analysis and biogeography of the south- west. Pages 433-452 in H. E. Wright and D. G. Fray, eds., The Quaternary of the United States. Princeton University Press, Princeton, New Jersey. Meyer, S. E. 1978. Some factors governing plant distribu- tions in the Mojave-Intermountain transition zone. Great Basin Nat. Mem. 2: 197-207. Miller, A. H 1941. A review of centers of differentiation for birds in the western Great Basin region. Con- dor 43: 257-267. MOECK, A. H. 1957. Geographic variability in Speijeria. Comments, records and description of a new sub- species. Milwaukee Ent. Soc. , Special Paper. Murphy, D.. and P R. Ehrlich. 1983. Biosystematics of the Euphijdnjas of the Great Basin with the de- scription of a new subspecies. J. Res. Lepid. 22; 254-261. Murphy, D. D.. and B A Wilcox. 1985. Buttei-fly diver- sity in natural habitat fragments: a test of the valid- ity of vertebrate-based management. In]. Verner, M. L. Morrison, C. J. Ralph, and R. H. Barrett, eds.. Modeling habitat relationships of terrestrial vertebrates. University of Wisconsin Press. Murphy, D D , B A Wilcox, G. T. Austin, and P R Ehrlich 1986. Butterflies of the Great Basin ranges. J. Res. Lepid., in press. Perkins, S. P., and E. M Perkins, Jr 1967. Revision of the Limenitis weidemeijerii complex, with descrip- tion of a new subspecies (Nymphalidae). J. Lepid. Soc. 21:213-234. Pratt. W L. 1985. Insular biogeography of central Great Basin land snails: extinction without replacement. J. Arizona-Nevada Acad. Sci. (1985 Proc. Suppl.) 20: 14 (abstract). Rogers, G. F. 1982. Then and now. A photographic his- tory of vegetation change in the central Great Basin Desert. University of Utah Press, Salt Lake Citv. Scott. J A 1986. The butterflies of North America, a natural history and field guide. Stanford Univer- sity Press, Stanford, California. Shapiro. A. M., C. A. Palm, and K L Wcislo 1979. The ecology and biogeography of the butterflies of the Trinitv Alps and Mount Eddy, northern Califor- nia. J.' Res. Lepid. 18;69-15L Shields, O 1977. Studies on North American Philotes (Lycaenidae). V. Taxonomic and biological, notes continued. J. Res. Lepid. 16: 1-67. Smith, GR. 1978. Biogeography of intermountain fishes. Great Basin Nat. Mem. 2: 17-42. Sterbins. R. C 1954. Amphibian and reptiles of western North America. McGraw-Hill, New York. Stutz. H. C. 1978. Explosive evolution of perennial Atriplex in western America. Great Basin Nat. Mem. 2: 161-168. Swisher. W L. and A L Morrison. 1969. News, notes — one desirable species. News Lepid. Soc. 1969(3): 4. Tanner, W W. 1978. Zoogeography of reptiles and am- phibians in the intermountain region. Great Basin Nat. Mem. 2: 43-53. Thomas. D H 1983. Large mammals. In D. H. Thomas, ed.. The archaeology of Monitor Valley. 2. Gate- cliffShelter. Amer. Mus. Nat. Hist. Anthrop. Pap. 59: 126-129. Watt, W B. 1968. Adaptive significance of pigment poly- morphisms in Colias butterflies. I. Variation of melanin pigment in relation to thermoregulation. Evolution 22: 437-458. Wells, P V 1983. Paleobiogeography of montane islands in the Great Basin since the last glacialpluvial. Ecol. Monogr. 53: 341-382. WiELGUS, R. S,. and D. Wielgus 1974. A new sandy- desert subspecies of Megathymus coloradensis (Megathymidae) from extreme northern Arizona. Bull. Allyn Mus., No. 17. Wilcox, B. A , D D Murphy. P R Ehrlich, and G T. Austin. 1986. Insular biogeography of the montane butterfly faunas in the Great Basin: comparison with birds and mammals. Oecologia69: 188-194. REPRODUCTIVE ECOLOGY OF BLACK-TAILED PRAIRIE DOGS IN MONTANA Craig J. Knowles' Abstract. — Reproductive ecology of black-tailed prairie dogs (Cijnomys ludovicianus) was studied on the Charles M. Russell National Wildlife Refuge in northeastern Montana (1978-1980 and 1985). Breeding took place from early March through early April in most years. Persistent snow cover and below normal temperatures in February and March of 1978 delayed the start of breeding. Litter size averaged 4.4 but varied significantly among years. Average yearly litter size was correlated (r" = 0.986) with summer (June-September) precipitation prior to the breeding season. Largest average yearly litter size (5.0) followed record precipitation, while the smallest average yearly litter size (3.8) followed extreme drought. More than half the yearling females failed to breed while 88% of the females two years and older bred. Testes weights were greatest early in the breeding season and regressed rapidly during April. Black-tailed prairie dogs {Cynomys ludovi- cianus) occur throughout the Great Plains from southern Canada to Texas within an area of great climatic variation. Such climatic varia- tion may be expected to influence timing of breeding and possibly reproductive potential of prairie dogs. Various aspects of prairie dog reproductive ecology have been studied over a wide geographic region (Wade 1928, An- thony and Foreman 1951, Anthony 1953, King 1955, Koford 1958, Davis 1966, Tileston and Lechleitner 1966, Foreman 1968, Kerwin 1972, Stockrahm 1979, Garrett et al. 1982, Hoogland 1982a, b). Although many of these studies are of one reproductive season or of a single colony, some variation in timing of breeding and number of young is apparent. Breeding in prairie dogs begins as early as late January in Oklahoma (Anthony and Foreman 1951) and as late as mid-March in North Da- kota (Stockrahm 1979). Timing of breeding in prairie dogs could not be altered by manipu- lating temperature and photoperiod in a labo- ratory (Foreman 1968). Females come into estrus for one day only (Hoogland 1982b), and their gestation period is estimated between 32 and 35 days (Anthony and Foreman 1951, Hoogland 1986). Reports of average in-utero litter size have ranged from 4.0 (Smith 1967) to 5.2 (Tyler 1968). My study examined timing of breeding and number of young produced by black-tailed prairie dogs in Montana and sought to determine whether environmental variables might influence these parameters. Montana Cooperative Wildlife Research Unit. University of Montana, Mis 113, Boulder, Montana 59632. Methods Prairie dogs were collected at six colonies by shooting in spring of each year from 1978 to 1980 and again in 1985 on the Charles M. Russell National Wildlife Refuge in northeast- ern Montana (108°30'W, 47°45'N). Collec- tions were timed to obtain pregnant females or females shortly postpartum. Some presam- pling in March and early April was needed to establish the onset of breeding in 1978 and 1979. The majority of prairie dogs was col- lected during the second and third weeks of April except in 1978 when many individuals were collected in May. Sex, weight, and total length were recorded for each prairie dog. Lower mandibles were examined and assigned to one of three age groups based on wear of molariform teeth. These groups and criteria for classification were as follows: (1) light wear, cusps showing little or no wear; Stockrahm (1979) found this wear pattern to be characteristic of yearlings (one to two years old); (2) moderate wear, cusps showing definite wear but still very dis- tinct; and (3) great wear, cusps worn enough to be indistinct. According to Stockrahm (1979), considerable overlap occurs in tooth wear between age classes of prairie dogs over two years; thus, the tooth-wear classes are considered only general indications of age. Numbers of embryos or uterine scars were recorded for each necropsied female. A crown-rump measurement was taken for all embryos from 1978 through 1980 but only for nila, Montana .59812, Present address; FaunaWest Wildlife Consultants, Box 202 April 1987 Knowles: Montana Prairie Docs 203 Table 1. Average crown-rump measurements (mm) and percentage of lactating females by week of collection during April 1978, and the years 1979, 1980, and 1985 combined. 1978 N 1979, 1980 , 1985 Crown-Rump Percent lactating Crown -Rump Percent lactating Week Mean SD Mean SD N 1-7 8-14 15-21 22-28 12.0 10.0 0 17 <5 27.6 39.9 46.4 15.8 21.2 12.5 0 8 23 68 2 60 13 22 Table 2. Summary of reproductive parameters for female prairie dogs collected on the Charles M. Russell National Wildlife Refuge, Montana. N Percent breeding Breeding females All females Year X Embryos SD X Embryos SD 1978 47 63 4.4 1.2 2.7 2.3 1979 58 67 5.0 1.4 3.6 2.6 1980 46 74 3.8 0.8 2.8 1.8 1985 39 67 4.1 1.0 2.8 2.2 Total 190 67 4.4 1.2 3.0 2.3 a single embryo of each litter in 1985. Testes were weighed to the nearest 0. 1 g for animals collected from 1978 through 1980. A one-way ANOVA was used to test for variation of litter sizes among years, litter sizes among tooth-wear classes, and weights of males and females among years. Chi-square test of homogeneity was used to test for diflPer- ences in proportions of breeding females among years and among tooth-wear classes. Differences in weights and lengths between males and females were tested for significance with a Students t-test. Iterative correlation coefficients were calculated to determine the time period prior to breeding that precipita- tion most closely correlated with yearly aver- age litter size. Similar calculations were also made to determine the relationship of body weight with precipitation for male prairie dogs collected in April. Females were ex- cluded from this analysis because weights of embryos were not subtracted from their body weight. Results A total of 367 prairie dogs (198 females, 169 males, P > 0.10, X" = 2.292, 1 d.f.) was col- lected between 11 March and 27 May. Lactat- ing females were collected as earlv as 17, 13, and 14 April in 1979, 1980, and 1985, respec- tively. In 1978 no lactating females were col- lected up to 21 April, but collections were not resumed until 13 May, at which time lactating females predominated in the collection. Small embryos (less than 5 mm crown-rump) were noted in the collection as late as 19 April 1978, 17 April 1979, 13 April 1980 and 1985. These data suggest that breeding started as early as the second week of March and continued into early April. Breeding appeared to be delayed in 1978 (Table 1). Average crown-rump mea- surements were smaller for embryos taken during the third week of April in 1978 com- pared to other years. The first detected emergence dates for young were 11,2, and 1 June for 1978, 1979, and 1980, respectively. No comparable obser- vations were available for 1985. An average of 44 days elapsed between earliest parturition date and first emergence date for these years. In 1977 I observed young above ground on 24 May, and S. Olson (personal communication) reported young up on 14 May in 1981, sug- gesting that breeding may have taken place even earlier during those two years. Variation in timing of breeding among years appeared to be related to temperature and snow cover during February and March. These two months in 1977 and 1981 were extremely mild, with only sporadic snow cover and mean temperatures around 2 C (U.S. Dept. of Com- merce, Roy 24 NE). In contrast, total snowfall in the winter of 1978 exceeded 2 m, snow remained on the ground until early April, and the mean temperature was -5 C for those two months. Although mean temperature during Februarv and March 1979 was similar to 1978, 204 Great Basin Naturalist Vol. 47, No. 2 Table 3. Comparison of female reproductive parameters by tooth-wear class together with percentage wear-class distribution by year for 181 females. Tooth- wear Percent breeding 40 85 94 Breeding 9S All 9 9 Wear -class distribution (%) class Light Moderate Great X Embryos 4.7 4.4 4.2 — SD 1.2 1.1 1.3 X Embryos 1.9 3.8 3.6 SD 2.4 1.9 1.9 1978 53 30 16 1979 50 26 24 1980 1985 44 21 40 .56 16 23 Table 4. Percentage of pregnant females examined by year with one or more resorbed embryos together with percentage of embryos resorbed. Percent pregnant Percent Year N resorbing embryos resorbed embryos 1978 20 30 6.2 1979 21 24 4.6 1980 28 21 5.6 1985 26 23 7.1 Total 95 24 5.9 snowfall was less and the snow melted oflP earlier; 1980 and 1985 were intermediate to these extremes. Approximately two-thirds of all females col- lected had bred. The distribution of breeding females among years was homogeneous (P > 0.75, X' = 1.169, 3 d.f ) (Table 2). Litter size averaged 4.4 (SD ±1.2, range 1-8) but varied among years (P < 0.005, F = 7.4, 127 d.f) (Table 2). Average yearly litter size ranged from 5.0 in 1979 to 3.8 in 1980. Record precip- itation occurred in 1978 (57.1 cm), while drought conditions existed on the study area in 1979 and 1980 (27.6 and 22.2 cm for 1979 and 1980, respectively, U.S. Dept. of Com- merce, Roy 24 NE). Average litter size was best correlated with summer (June-Septem- ber) precipitation of the previous year (r" = 0.986) but showed little correlation with late- fall/winter (November-March) precipitation (r~ = 0.004). Number of embryos produced by all females averaged 3.0 and showed less vari- ation among years than did average yearly litter size (embryos/breeding female). The distribution of breeding females was not homogeneous among tooth-wear classes (P < 0.005, X' = 48.620, 2 d.f) (Table 3). Only 40% of the females showing light tooth wear had bred. Among the females showing great tooth wear, 94% had bred. Average litter size did not vary (P > 0.25, F = 0.9, 119 d.f) among tooth-wear classes, although there was a tendency for younger animals to have larger litters. However, because of low pregnancy rate, the average number of embryos per fe- male in the light tooth-wear class was only about half that of the other two wear classes. Evidence of post-implantation mortality (resorption) was found each year. Resorbing embryos were found in nearly a quarter of the pregnant females (Table 4), and 5.9% of the embryos were lost. Of the 23 pregnant fe- males found to be resorbing embryos, only two were resorbing more th^n one. In 1985 one female was resorbing all three embryos, and another was resorbing two of three em- bryos. Average total length of males (X = 383.7, SD ±26.3 mm) was greater (P < 0.001, t = 5.966, 356 d.f) than that for females (X = 369.0, SD ±20.4 mm). However, no differ- ence was noted (P > 0.50, t =_0.415, 283 d.f) in average weight of females (X = 810.8, SD ± 145.0 g) and males (X = 803.5, SD ± 146.4 g) collected during April. This may be ac- counted for by the fact that many females were pregnant at the time of collection. Weights of both females and males taken dur- ing April varied among vears (females, P < 0.05, F = 3.1, 166 d.f; males, P > 0.05, F = 2.4, 117 d.f). Weights of males were most closely correlated (r" = 0.627) with precipita- tion from June through October of the previ- ous year. Average testes weight was greatest during March (X = 3.45, SD±_2.32 g, N = 12) and declined through Api2l_( X = 0.59, SD± 0.42 g, N = 93) and May (X = 0.38, SD± 0.26 g, N = 18). Of the five male prairie dogs col- lected during the month of March that were assigned to the light tooth-wear class, only two had testes weights exceeding 1.0 g. Testes weights of older males collected during this month averaged 5.0 g, suggesting that many younger males may not participate in breed- ing. Testes of nearly all males collected in April were held abdominally. April 1987 Knowles: Montana Prairie Dc)c;s 205 Discussion Timing of breeding in prairie clogs has been variously reported to take place from January through March and appears to occur later with increasing latitude (Johnson 1927, Wade 1928, Anthony and Foreman 1951, King 1955, Koford 1958, Davis 1966, Tileston and Lech- leitner 1966, Tyler 1968, Stockrahm 1979). Breeding took place over an extended period from early March to early April during this study. King (1955) and Tileston and Lechleit- ner (1966) noted that breeding occurred over a one- to two-week period. Although Fore- man (1968) found that timing of breeding in female black-tailed prairie dogs could not be altered by manipulating temperature and photoperiod, it was apparent in m\' study that prairie dogs bred later in 1978 as a result of persistent snow cover during March of that year. Time between birth and emergence of young has been estimated at 56 days by An- thony and Foreman (1951), 45 days by King (1955), 32 to 39 davs by Tileston and Lechleit- ner (1966), and 43^4 days by Hoogland (1986). Litter size varied considerably among years and appeared to be influenced by precipita- tion from the previous year, which may also influence body weight of prairie dogs in April. Reproductive failure has been reported to oc- cur in Townsend's ground squirrels {Sper- mophilus townsendii) under drought condi- tions in Idaho (BLM, U.S. Dept. Interior 1979). Reports of average in-utero litter size range from 4.0 to 5.2 (Johnson 1927, Wade 1928, Anthony and Foreman 1951, Koford 1958, Tileston and Lechleitner 1966, Tyler 1968) with no apparent geographical trend. The influence of yearly climatic conditions on litter size may account for this. Despite the varying climatic conditions during this study and the resulting wide range in average litter size among years, the propor- tion of females breeding among years re- mained fairly constant with about two-thirds of the females breeding each year. Wade (1928) reported breeding in 74% of 68 female prairie dogs, and Anthony and Foreman (1951) found 73% of 15 wild-caught females to have bred. My data show that only 40% of the light tooth-wear class (i.e., yearlings) females had bred, whereas most of the females in the two older age classes had bred. King (1955) reported no breeding by yearling females, and Tileston and Lechleitner (1966) found only one breeding yearling female. During another segment of my study involving live trapping and marking (Knowles 1982), I did not document breeding of yearlings in 27 cases in two colonies over two breeding sea- sons. However, Koford (1958) reported about one-third of the yearling females he collected in Colorado had bred. Stockrahm (1979) found the majority of yearlings in two colonies bred, but in two other colonies very few bred. Gar- rett et al. (1982) found breeding in yearlings to vary between colonies and years. Evidently breeding in yearling females is highly vari- able. Resorption of embryos was a common oc- currence each year. Despite some variation among years in both percent of females re- sorbing embryos and the percent post-im- plantation mortality, this did not appear to be related to environmental factors. Anthony and Foreman (1951) found evidence of resorp- tion in 3 of 13 (23%) pregnant females and suggested that resorption in prairie dogs may be common. Testes of most males were in regression at least two weeks before the breeding season terminated. Anthony (1953) found peak testes weight to correspond with the beginning of estrus in females and that regression of acces- sory sex glands lagged behind the testes, sug- gesting that males are capable of breeding as long as mobile sperm are present. My data indicated that many yearling males may not attain sexual maturity. Anthony (1953) found that young raised in a laboratory attained sex- ual maturity a month after older adults. Year- ling males were reported not to participate in breeding in a studv conducted by Hoogland (1982a). Acknowledgments This research was funded by the U.S. Fish and Wildlife Service, Refuge Division. I thank Dr. B. OGara for technical advice and guidance in all phases of this study, S. Gieb, R. Gumtow, P. Knowles, S. Schmidt, D. Schuster, and C. Stoner for field assistance, and Drs. B. OGara and J. Ball for manuscript review. 206 Great Basin Naturalist Vol. 47, No. 2 Literature Cited Anthony, A 1953. Seasonal reproductive cycle in the normal and experimentally treated male prairie dog {Cijnomtjs hidovicianus). J. Morphol. 9.3: 331-370. Anthony, A,, and D Foreman 19.51. Oh.servations on the reproductive cycle of the black-tailed prairie dog {Cynomys htdovicianus). Physiol. Zool. 24: 242-248. Davis, A. H 1966. Winter activity of the black-tailed prairie dog in north-central Colorado. Unpub- lished thesis, Colorado State University, Fort Collins. 45 pp. Foreman, D L 1968. The normal reproductive cycle of the female prairie dog and the effects of light. Anat. Rec. 142; .391-405. Garrett, M C, J. L Hoogland, and W L Franklin 1982. Demographic differences between an old and a new colony of black-tailed prairie dogs {Cynomys ludovicianus). Amer. Midi. Nat. 108: 51-59. Hoogland, J L. 1982a. Prairie dogs avoid extreme in- breeding. Science 215: 16.39-1641. 1982b. Variance in male and female reproductive success in a harem-polygynous mammal, the black-tailed prairie dog (Sciuridae: Cynomys lu- dovicianus). Behav. Ecol. Sociobiol. 11: 155-163. 1986. Infanticide in prairie dogs: lactating females kill offspring of close kin. Science: in press. Johnson, G E 1927. Observations on young prairie dogs (Cynomys ludovicianus) born in the laboratory. J. Mammal. 8: 110-115. Kerwin, L. 1972. Population size and productivity of the black-tailed prairie dog in Saskatchewan. Blue Jav 29: 35-37. King, J. 1955. Social behavior, social organization, and population dynamics in a black-tailed prairie dog town in the Black Hills of South Dakota. Contrib. Lab. Vert. Biol. 67. University of Michigan, Ann Arbor. 123 pp. Knowles, C. J 1982. Habitat affinity, populations, and control of black-tailed prairie dogs on the Charles M. Russell National Wildlife Refuge. Unpub- lished dissertation, L'niversity of Montana, Mis- soula. 171 pp. Koford, C B 19.58. Prairie dogs, whitefaces, and blue grama. Wildl. Mono. 3. 78 pp. Smith, R E 1967. Natural history of prairie dogs in Kan- sas. Kansas Univ. Nat. Hist. Misc. Publ. 49. 39 pp. Stockrahm, D M R B 1979. Comparison of population structure of black-tailed prairie dog, Cynomys I. ludovicianus (Ord), towns in southwestern North Dakota. Unpublished thesis. University of North Dakota, Grand Forks. 103 pp. TiLESTON, J V , and R. R Lechleitner 1966. Some com- parisons of the black-tailed and white-tailed prairie dogs in north central Colorado. Amer. Midi. Nat. 75: 292-316. Tyler, J D 1968. Distribution and vertebrate associates of the black-tailed prairie dog in Oklahoma. Un- published dissertation. University of Oklahoma, Norman. 85 pp. US Department of Commerce. Weather Service. 1977-1985. Climatological data, Montana monthly summaries. U.S. Govt. Printing Office, Washington, D.C. US Department of Interior, Bureau of Land Man- agement 1979. Snake River birds of prey special research report. BLM, Boise District, Idaho. 142 pp. Wade, O. 1928, Notes on the time of breeding and num- ber of voung of Cynomys ludovicianus. J. Mam- mal. 9: 149- 151. FIELD CLINIC PROCEDURES FOR DIAGNOSIS OF ECHINOCOCCUS GRANULOSUS IN DOGS' Ferron L. Andersen" and M. Jolm Ramsay' Abstract — Echinococcus ^.ranulosus is the causative parasite of hydatid disease in humans and represents a significant puhhc health prolilem witliin endemic foci in all major continents of the world. This report gives a detailed set of instructions whereby four trained indi\ iduals can examine 15-20 dogs per hour for the presence of this organism. The procedure permits the baseline determination of the prevalence of this parasite within any specific population of dogs and also allows the periodic examination of the same aniiuals to determine if recommended preventive and control measures for hydatid disease are being followed by sheep and dog owners in any region where the parasite is known to occur. Echinococcus granulosus is an extremely small tapeworm (4-6 mm in length; Fig. I) that lives in the small intestine of dogs and a few related carnivores (e.g., coyotes and wolves). Eggs from the fully developed tape- worm are passed out with the fecal material from the carnivore host. Sheep (and a variety of other domestic and wild animals such as cattle, pigs, deer, and moose) may ingest veg- etation contaminated with the carnivore host feces containing these tapeworm eggs. Once the eggs have been ingested by these animals (intermediate hosts), the tapeworm eggs hatch in the duodenum, penetrate through the intestinal lining, and pass via the blood- stream to such filtering organs as the liver or lungs. There the hatched eggs undergo devel- opment to the larval stage (termed hydatid cysts; Fig. 2) and become filled with watery (hydatid) fluid. The hydatid cysts continue to grow inside these animals, and tiny micro- scopic tapeworm heads (termed protoscolices; Fig. 3) develop inside the cysts by extensive asexual reproduction. Once an animal is in- fected with these hydatid cysts, it has them for the remainder of its life. When that animal dies or is killed, the viscera with the hydatid cysts may be eaten by a dog or other carni- vore. The protoscolices are then liberated from the cyst, attach to the intestinal lining of the carnivore, and develop to the tapeworm stage (Schantz 1982). The life cycle of £. gran- ulosus is given in Figure 4. Developmental time in the dog after it eats viscera containing hydatid cysts from an in- fected sheep imtil mature tapeworms can be found in the dog s intestine is about 35 days (Thompson 1986). Developmental time in the sheep after it ingests vegetation contaminated with fecal material from the dog containing tapeworm eggs until mature hydatid cysts with protoscolices can be found in the sheep viscera is approximatelv one vear (Schantz 1982). People who work in close association with dogs and sheep that harbor this tapeworm are also at some risk of contacting the parasite. If such individuals inadvertently ingest some of the tapeworm eggs passed from an infected dog (either from petting or handling the dog or from ingesting food or drink contaminated with dog feces), hydatid cysts may eventually develop within the internal organs of that per- son. Such an infected person is said to have hydatid disease or echinococcosis. The cysts will continue to grow and develop and may become so large as to interfere with the nor- mal functioning of the particular organ (liver, lung, etc.) in which the cysts are located. Al- though there are several chemical compounds that will effectively retard the growth of hy- datid cysts in humans, there are no com- pounds that will remove or eliminate the cyst entirely. Consequently, the cysts must on oc- casion be removed through surgery. Such an operation is naturally very serious, depending This project was supported in part by US Piililic Health Ser\ice Crant Al-lOSSS ami In hmds Brigham Young University, Provo, Utah 84602. "Department of Zoology , Brigham Young University. Provo. Utah 84602. Moroni Feed Company, Moroni, Utah 84646. located from the C^ollege of Biologv' and Agriculture, 207 208 Great Basin Naturalist Vol. 47, No. 2 Fig. 1, Adult Echinococcus granulosus tapeworm from an infected dog. Fig. 2. Hydatid cysts in liver from an infected sheep. Fig. 3. Protoscolices from a hydatid cvst. April 1987 Andersen, Ramsay: Tapeworms in Dogs 209 Fig. 4. Life cycle of Echinococcus granulosus: A, Dog (carnivore host) infected with Echinococcus granulosus tapeworm in small intestine; this animal becomes infected after eating viscera of sheep (or a related animal) containing hydatid cysts; B, Adult Echinococcus granulosus tapeworm (4-6 mm) in small intestine of dog; C, Tapeworm egg (30-40 jjl) passed in feces from an infected dog; D, Sheep (intermediate host) with hydatid cysts in viscera; this animal becomes infected after ingesting vegetation contaminated with dog feces containing tapeworm eggs; E, Hydatid cysts in viscera of sheep; F, Tissue section through hydatid cyst with daughter cysts and numerous protoscolices (tiny tapeworm heads); G, Human with hydatid cysts in liver and lung; people become infected after ingesting food or drink contaminated with dog feces containing tapeworm eggs, or by handling or playing with infected dogs. 210 Great Basin Naturalist Vol. 47, No. 2 upon the size and specific location of the de- veloping cyst(s), and in rare cases it may be fatal (Schantz 1982). At the present time hydatid disease is known to be endemic in parts of Europe, Asia, Africa, South and Central America, New Zealand, and Tasmania. Although the disease is relatively rare in North America, known endemic foci do exist in such places as Alaska, Utah, Arizona, New Mexico, and the Central Valley of California (Gemmell 1979, Andersen 1986). In many countries of the world where hy- datid disease is known to be a significant prob- lem, surveillance studies are routinely done to determine the prevalence oi Echinococcus granulosus in people, sheep, and dogs (Bar- bour etal. 1978, Condieetal. 1981, Andersen etal. 1986). Data for the prevalence of hydatid cysts in people come mainly from a survey of hospital records. Data for the prevalence of hydatid cysts in sheep are obtained most often from records at slaughter houses or from a survey of sheep owners who may have ob- served hydatid cysts in sheep they have killed. However, information on the preva- lence of £. granulosus tapeworms in dogs is more difficult to obtain. As stated above, these particular tapeworms are extremely small and are not seen by the dog owner or even by the veterinarian at routine inspec- tions. They can, however, be detected by a very thorough examination of the intestinal contents after the dog is killed. This works well for examining dogs suspected of harbor- ing this parasite if the dogs are either strays or not needed as working dogs. Obviously, many of the dogs in an agricultural region are re- quired as working dogs for the sheep industry and, as such, cannot be killed; yet these dogs are the very ones that most likely will be infected with this particular tapeworm. In those cases, the prevalence of £. granulosus may be determined through using purgation techniques — i.e., use of a strong laxative (Gemmell 1973, Schantz 1973). Such a proce- dure not only allows the determination of baseline data on this parasite within dogs liv- ing in a specific region, but it also allows the periodic examination of the same animals to determine if recommended preventive and control measures for this disease are being followed by sheep and dog owners in that area. Sheep ranchers must do all they can to prevent dogs from having access to viscera of any infected sheep that might die at their farmstead or range. Specifically, they must not purposefully feed sheep viscera to dogs when the sheep are butchered for mutton (Andersen et al. 1983). Materials and Methods for Purging Dogs The following information is designed as a set of recommended instructions for purging dogs at a field clinic in a rural community where sheep raising is an important part of agriculture. The specific protocol described requires four trained individuals and is de- signed to allow the examination of approxi- mately 15-20 dogs per hour. A. Initial organization. 1. Obtain all necessary approvals from lo- cal health officers who may need to be involved or give sanction to the clinic. 2. Advertise details of the clinic through: a. any local newspapers; b. personal letters to dog or sheep owners where feasible; c. announcements sent to schools, churches, or community centers; d. posters displayed at local stores or community centers. 3. Details should include; a. nature of hydatid disease; b. its public health significance; c. exact location, date, and time of field clinic; d. instructions to dog owners to: (1) withhold all food from their dog for 12 hr before the examination (water should be continually available, however); (2) bring each dog with a sturdy leash; (3) be prepared to sign a "release of responsibility" form for the ex- amination team. 4. Select a site for the clinic somewhat removed from any residential area, playground, public school, or major traffic region. The area where the dogs are to be tied should be relatively free of tall grass, bushes, and any other ob- jects that would inhibit the eventual collection of purged fecal samples. Generallv, it is best to avoid the use of April 1987 Andersen, Ramsay: Tapeworms in Dogs 211 5 B c33> Fig. 5. Materials for dosing line: A, Long, sturdy rope; B, Metal stakes and stake driver; C, "Choke ehain" type leash; D, Identification tags; E, Scales. cement foundations, paved lots, or even graveled roads. A relatively firm soil substrate nearly free of vegetation seems to be the best type location for a field clinic. Preparation on day of clinic. 1. All members of the examining team should arrive at the clinic site in suffi- cient time to be completely organized before owners start to bring dogs for examination. The four members of the team should be assigned to separate duties: a. No. 1 interviews owners and regis- ters all dogs. b. No. 2 administers all purgative medicine. c. No. 3 collects all purged samples. d. No. 4 examines all samples. 2. A good sturdy fence which dogs cannot jump over or climb through is the best place to tie the individual dogs. If a good fence is not available, a temporary "dosing line' can be constructed with metal posts and a long, heavy rope. Dogs can be tied about 2.5 m apart on a very short leash. This will minimize fighting among the dogs and will lessen any confusion as to which fecal samples belong to which dog. The rope, stakes, stake driver, leashes, individual tags, and scales are shown in Figure 5. All members of the examination team should wear protective clothing (Fig. 6), with the exception of the individual who is assigned to interview the dog owners. That person should not wear a mask or use gloves so that he or she can communicate easily with those who at- tend the clinics and can also handle all records and educational aids. The wearing of protective clothing serves to protect the members of the examina- tion team and also emphasizes to those who attend the clinic the potential seri- ousness of hvdatid disease. 212 Great Basin Naturalist Vol. 47, No. 2 O^ AREC. HBr Fig. 6. Protective clothing, chemicals, drugs, and miscellaneous solutions: A, Face mask; B, Latex disposable gloves; C, Coveralls; D, Boots; E, Water container; F, Graduated cylinder; G, Sucrose; H, Arecoline HBr (purgative) and syringe without needle; I, Atropine sulfate (antidote) and syringe with needle; J, Prazicjuantel (therapeutic drug) and syringe with needle; K, AFA tapeworm preservative solution. 4. A disposal pit into which collected fecal material and disposable items and sup- plies can be placed should be dug in close proximity to the examination site. The pit needs to be about the size and depth of a regular 30-gal garbage can. If a disposal pit cannot be dug at the clinic site, a large garbage can fitted with a sturdy plastic liner should be available. C. Registration of dogs. 1. As the dogs arrive, one member of the examining team is assigned to greet and interview each owner to obtain the following information: a. name and address of dog owner; b. name, age, sex, breed, any identify- ing features, and weight of dog (owner can hold dog on scales and then subtract own weight without dog); c. history of the dog's use in agricul- ture, including answers to the fol- lowing questions: (1) Does dog have contact with sheep? (2) Does owner have sheep? If so, how many? (3) Does owner allow dog to eat sheep viscera? (4) Has dog been treated within the past year for tapeworms? 2. Owner is requested to read and sign a "release of responsibility' form (Fig. 7) that releases all members of the exami- nation team from any and all financial obligation should the dog be injured or die as a result of the purgation or subse- quent treatment. 3. Owner is then given educational aids concerning the nature and transmissi- April 1987 Andersen, R\msav: Tapeworms in Dogs 213 7 Fig. 7. Registration forms, educational materials, and sur\e\' record sheets: A, Registration data form (top portion), release of responsibility statement (middle portion), results of examination for all dogs belonging to one owner (bottom portion); B, Educational materials for those who attend clinic; C, Preserved specimens oi Echinococcus granulosus tapeworms from an infected dog and hydatid cysts from an infected sheep; D, Clipboard and record sheets for all dogs examined at the clinic. bility of hydatid disease and is shown the sample of preserved Echinococcus granulosus tapeworms from an in- fected dog and the sample of a pre- served hydatid cyst from an infected sheep (Fig. 7). 4. The dog is then taken to the dosing line where it is individually tethered (Fig. 8). An identification number is given to each dog as it is entered onto the line, and that number is placed on all regis- tration forms and the master list for that particular clinic. D. Administration of the purgative solution. 1. Arecoline HBr is the purgative agent used and should be premi.xed as fol- lows: 1.5 g of drug added to 100 ml of water (Fig. 6). Also, sucrose (about 15 g) is added as a sweetener to remove the unpleasant, bitter taste of the com- pound. The addition of a sweetener is especially important if the dog might need to receive more than one dose on the day of the clinic or if it will be brought back to another clmic at a later date. A veterinarian or one specifically trained individual on the examining team should be assigned to administer all purging medicine at any one clinic. If a dog is tame and manageable, this person can probably give the purgative without help from an assistant (Fig. 9A). If, however, the dog is somewhat unmanageable, it is best for the owner or another member of the team to hold the dog firmly as shown in Figure 9B while the first person administers the drug. Arecoline HBr is administered at a dosage level of 1 ml/4.5 kg (10 lbs) of body weight. The drug should be quickly deposited at the back of the tongue to facilitate swallowing. The mouth of the dog is quickly closed, the 214 Great Basin Naturalist Vol. 47, No. 2 Fig. 8. Dogs iiidivicliially tethered to dosing line. 9b Fig. 9. Illustration of purging technique: A, One-man procedure for manageable dogs; B, Two-man procedure for unmanageable dogs. muzzle elevated somewhat, and the at- tendant should make sure that the dog swallows the entire dosage amount. If an unmanageable dog is restrained by the owner or second assistant, that per- son 7niist not release the head of the dog until the person administering the drug has pulled away from the dog's mouth. Every effort should be made to handle the dogs gently but firmly. Tight restraint should be used only when necessary, and a good practicing veterinarian should be able to dose most of the dogs single-handedly. The time when each dog receives arecoline is recorded on the identifica- tion tag and also entered onto the indi- vidual registration form. Shortly after the compound is administered, most dogs will begin to salivate heavily and will also usually vomit. This material should be collected readilv and dis- April 1987 Andersen, Ramsay: Tapeworms in Dogs 215 carded into the disposal pit or garbage container. Some dogs may show mod- erate to severe reactions to the arecol- ine HBr and may exhibit marked dis- tress, cardiac excitation, convulsion, and collapse. Generally, such reactions are only temporary. In persistent cases, however, the veterinarian (or person in charge of dosing with arecol- ine) must be prepared to administer an antidote of atropine sulfate. This is given intramuscularly or subcuta- neously at a dose rate of 0.05 to 0.1 mg/kg (Fig. 6). This antidote should allow the dog to recover rapidly; how- ever, it will also probably stop the pur- gation reflex and that particular dog will then need to be released from the dosing line without further examina- tion. Pups under four months, ex- tremely old dogs, and pregnant or lac- tating female dogs should probably not be purged (Andersen 1986). In addi- tion, it has been our experience in holding clinics in central Utah over the past 15 years that the small "toy breeds" are likely to show adverse re- actions to an arecoline purge. E. Collection and examination of purged samples. 1 . In most circumstances when the purga- tion process proceeds normally, the dog will first void solid to semi-solid fecal material. Since this portion rarely contains parasites, it should be col- lected from the ground immediately and discarded. After a short delay the second purged material should be a much more liquified portion with small to moderate amounts of mucus present. This portion (especially any mucus) should be carefully picked from the soil substrate with a tongue depres- sor and transferred to a labeled collect- ing cup. It is helpful if one attendant holds the dog by the leash to one side while the other attendant collects the purged sample. Additional purged amounts may be passed from the dog while it is tied to the dosing line. This material may be collected and exam- ined also if time is available and if the examiner is not satisfied with previous collections. 2. If, after approximately 30 minutes fol- lowing administration of the arecoline HBr, a particular dog has not purged and shows no signs of inner peristaltic distress, the attendant might exercise the dog with a short walk in the vicinity of the dosing line. Some dogs are ex- tremely reluctant to defecate while be- ing tethered, and the exercise might be an added stimulus to the purgation pro- cess. If after 45 minutes or so there has been no purgation whatsoever, the at- tendant veterinarian might elect to give a second purge (about one-half the initial level). In very rare instances, even a third dose might be given if the veterinarian deems the dog to be in sufficient health and constitution to withstand such a regimen. 3. When a good sample with mucus is passed, one attendant carefully collects the material, labels the collecting cup, and takes the container to a central lo- cation for examination (Fig. 10). To minimize any record-keeping errors and to maintain consistency in exami- nation procedures, one member of the team is assigned to do all examination for that particular clinic. 4. Several ml of tap water are added to the collecting cup from a squeeze bottle, and the material is carefully poured into a shallow black-bottom pan for ex- amination. The attendant carefully separates the collected sample with a teasing needle and methodically exam- ines the material with a gentle swirling motion of the pan. The examination should be done in ample lighting, which gives a good color contrast of the tiny white tapeworms against the black background of the examination pan. In cases where objects are difficult to dif- ferentiate, the object in question can be viewed under a hand lens or trans- ferred with a medicine dropper to a petri dish and examined in greater de- tail under a dissecting microscope (Fig. 6). Extreme care must be taken to ob- tain adequate purged samples and then view them with consistencv to locate 216 Great Basin Naturalist Vol. 47, No. 2 Fig. 10. E.xaniination supplies: A, Collecting cups and marker; B, Tongue depressors; C, Shallow hlack-hottom examination pan; D, Dissecting microscope; E, Water scjueeze bottle; F, Flashlight; G, Hand lens; H, Teasing needle; I, Medicine dropper; J, Petri dishes; K, Clock; L, Roll of paper. the tiny worms if indeed they are present. Care must also be taken to avoid misidentification of tiny white objects that might have an overall shape similar to the Echinococcus tapeworms. Broken or isolated scolices (tapeworm heads) or single proglottids (tapeworm segments) are extremely difficult to detect and differentiate from extraneous materials of similar size and shape. The results are recorded for each dog on the individual registration form and also on the master record for that day's clinic. A record should be kept of: a. the quality of the purge (i.e., good, fair, poor); b. presence of other worms (i.e., as- carids, large taeniids, etc. ; these can be preserved and identified at a later time if that is part of the project protocol since such information is helpful in assessing the eating habits of the dogs); c. presence of Echinococcus granulo- sus. F, Anthelmintic treatment. 1. Any dog shown to be infected with Echinococcus granulosus must be treated before the dog is taken from the dosing line. Injectable praziquantel (PZQ) at a dose level of 5 mg/kg is rec- ommended (Andersen et al. 1978). If the program is so designed, all dogs brought to the clinic (irrespective of whether or not they are found to harbor tapeworms) can be treated with the tapeworm medication (Fig. 6). 2. All treatment given should also be noted on the individual registration forms. G. Removal of dogs from dosing line. 1. As soon as a particular dog is finished, it should be removed from the dosing line, all purged fecal material should be collected and discarded, and a new dog entered onto that site on the dosing April 1987 Andersen, Ramsay: Tapeworms in Docs 217 Fig. 11. Clean-up materials: A, Garbage can and pla.stic liners; B, Water and hand soap; C, Paper towels; D, Propane burner and matches; E, Flat-bladed shovel; F, Round-bladed shovel; G, Hand pick. line. Dogs that are removed nia\ have rather soiled hindquarters and may need to be cleaned somewhat before leaving the area. It is important to keep the animal as clean as possible while it is on the dosing line and not to permit it to lie down in purged material. Since the dog may purge additional amounts after it has left the clinic site, and since any tapeworm eggs passed fiom a treated animal are probably not killed by praziquantel (Thakur et al. 1979), it is important that the dogs not be con- fined near the family home for one to two days following purgation. Owners should also be told of the significance of the results of the examination and be allowed to ask questions concerning the clinic. Members of the examining team should avoid using technical words not understood by dog owners or by other interested individuals who at- tend these field clinics. H. Clean-up at clinic site. 1. Figure 11 shows the materials and sup- plies necessary for proper clean-up fol- lowing the field clinic. After all dogs have been removed from the dosing line, all fecal material remaining should be collected with a flat-bladed shovel and discarded in the disposal pit or garbage container. A propane weed- burner or flame-thrower is then used to heat the area where the dogs have been tethered. Shovels and other equip- ment used by clinic personnel can be washed clean over the disposal pit and then flamed with the burner as well. If a temporary dosing line has been used, the rope should be recoiled without allowing it to get in the dirt, and the stakes should be carefully removed and reloaded into the team vehicle. 2. The individual assigned to keep all reg- istration forms and all records should not wear gloves or mask during the 218 Great Basin Naturalist Vol. 47, No. 2 clinic and should refrain from handling any potentially contaminated material. This individual should be responsible for putting away all records, visual aids, and all other materials that have not been handled by those individuals wearing gloves at the clinic. 3. Coveralls should be removed and placed in a plastic bag and should not be worn again without first being boiled in water. Gloves and masks should be discarded, and all team members should wash their hands carefully with soap and water and dry with disposable paper toweling. All other disposable items from the clinic should be discarded into the disposal pit, which should then be covered with an adequate amount of soil to prevent any dogs (or children) from digging into the buried material. If a large garbage can is used instead of a disposal pit, the plastic liner should be tied securely and then eventually incinerated or buried at another site. It is virtually impossible to describe each step of pre- caution that should be taken by the examination team, but each member should be expressly concerned about his or her own safety as well as that of the other members of the team. Discussion Arecoline HBr is a drug manufactured orig- inally from the areca nut which was used by the ancient Chinese for removal of intestinal worms. It was first used against tapeworms in dogs in 1921 (Schantz 1973). However, with the advent of newer, more effective an- thelmintics, the use of arecoline HBr in dogs has recently been limited to that of a diagnos- tic compound. The drug first causes the tape- worms to relax and lose their attachment to the intestinal mucosa; it then causes a marked contraction of the intestinal smooth muscles of the dog (Munday and Smith 1972). This re- sults in an expulsion (purgation) of some or many of the intestinal worms in an infected animals. The compound is known to remove about 90% of all tapeworms present in in- fected dogs in less than one hour after admin- istration, about half of the ascarid worms, but none of the hookworms (Batham 1946). Arecoline is used today in many parts of the world in areas where hydatid disease is known to occur as an integral part of preventive and control programs in which purging of dogs for detection of any Echinococciis tapeworms present is coupled with health education, con- trol of livestock slaughtering, and improved management of high-risk dogs (Schantz 1982). In central Utah the use of arecoline in field clinics has aided in the overall decrease of Echinococciis in infected dogs from a preva- lence of 28.3% in 1971 (Andersen et al. 1983) to 2.3% in 1984 (Andersen et al. 1986). This decrease substantiates the benefit of incorpo- rating arecoline purging into a control pro- gram for hydatid disease. Dog owners can see first hand if their dogs are indeed infected with these important parasites, which then gives immediate reinforcement to the overall program. Unfortunately, in one study in cen- tral Utah 92.5% of the dog owners surveyed knew the cause of hydatid disease and how the parasite was transmitted, 90% of them knew someone who had had surgical removal of hy- datid cysts, and yet nearly half of the respon- dents indicated they still allowed their dogs to sometimes eat part of the sheep carcass fol- lowing routine butchering on their premises or in the fields (Schantz and Andersen 1980). An important additional point for workers to remember where arecoline is used as a purging agent in dogs is that varied adverse effects such as tremors, difficulty in breath- ing, incoordination, and possible collapse can sometimes occur in dogs given this compound (Forbes and Whitten 1961). Also, some own- ers have complained that their dogs have been definitely weakened and were unable to work in the livestock industry for at least one day following purgation (Batham 1946). As discussed earlier, the actual examination for the tiny Echinococciis tapeworms is very difficult and is best left to experienced indi- viduals. Otherwise, false negative results may be recorded that would lead to improper con- fidence in the particular control program. In Echinococciis diagnostic field clinics, the use of arecoline in the hands of less-than-capable individuals may not only be useless but may even be dangerous if not carried out by expe- rienced personnel and in a standardized man- ner (Schantz 1982). In summary, the use of diagnostic field clin- ics for detection o{ Echinococciis tapeworms is April 1987 Andersen. Ramsav: Tapeworms in Dogs 219 best coupled with an intensive educational effort and with improved management pro- grams b\' all sheep and dog owners living in endemic regions (Crellin et al. 1982). Follow- ing the initial determination of baseline data on the prexalence of EcJiiuococciis tape- worms, periodic clinics thereafter with these same high-risk sheep dogs will pro\ ide the necessar\' index of progress which health au- thorities need to continue direction of suc- cessful campaigns in endemic regions. Literature Cited Andersen, F L 19S6. Diagnosis, prexcntion, and con- trol of h\ datid disease in North America. Pages 171-187 in G. T. Woods, ed.. Practices in \eteri- nary public health and preventive medicine in the United States. Iowa Press, Ames. Andersen, F L., G A. Conder. .^nd W P M.^rsland 1978. Efficacy of injectable and tablet formula- tions of praziquantel against matine Echinococ- cus granulosus. .\mer. J. \'et. Res. 39; 1861- 1862. Andersen. F. L . J R Crellin, C R Nichols, .\nd P M SCH.\,NTZ, 1983. Evaluation of a program to con- trol hydatid disease in central Utah, Great Basin Nat. 43: 65-72. Andersen. F L , L A Jensen. H D McCl rdv. .\ndG R Nichols, 1986. Three-year surveillance for ces- tode infections in sheep dogs in central Utah, Great Basin Nat, 48: 208-216, B,\rbolr. \ G . J R E\erett. F L Andersen, C R Nichols, T Fl ki shim,\, .^nd I G K.^g.\n 1978. H\ datid disease screening: Sanpete Count\-, Utah, 1971-1976. Amer. J. Trop. Med. Hvg. 27: 94-100. Baiiiwi E J 1946, Testing arccoline Indrobroniide as an antiielmintic for li\ ilatid worms in dogs. Parasitol- ogy .37: 185-191, CoNDiK, S J , J R Crellin F L .\ndf.hsk.n and P M ScnANTZ 1981. Participation in aconununity pro- gram to prevent hvdatid disease, Publ. Hlth. Lend. 95: 28-35. Crellin. J R . F L Andersen. P M Schantz. and S J CoNDlE 1982. Possible factors influencing distri- bution and prevalence oi Echinucoccus gr«/ii//o- .vi<.sin Utah. .Amer. J. Epidemiol. 116: 463-474. Forbes, L, S. and L K Whitten, 1961. Arecoline hydro- bromide as a purgative in dogs: the effect of method of administration on its speed of action. New Zealand \'et. J. 9: 101-104. Gemmell, M .\ 1973. Sur\eillance of Echinococcus granulosus in dogs with arecoline hvdrobromide. Bull. W'ld. Hlth. Org. 48: 649-652, ' 1979. H\datidosis control — a global view. Aus- tralian Vet. J. 55: 118-125. Ml'ND.W. B L,, AND M Smith 1972. Hydatid testing: the action and effects of arecoline hydrobromide when given to dogs. Tasmanian J. Agric. 43: 33-35. Schantz P M 1973. Gufa para el empleo del bromhidrato de arecolina en el diagnostico de la infeccion por Echinococcus granulosus en el perro. Bol. Chile Parasitol. 28: 81-90. 1982. Echinococcosis. Pages 231-277 in J. H. Steele, ed., CRC handbook series in zoonoses. Section C: Parasitic zoonoses, \'ol. I. Parts 1, 2. CRC Press, Boca Raton, Florida, Schantz. P M , and F L. Andersen. 1980. Dog owners and hvdatid disease in Sanpete Count\, Great Basin Nat. 40: 216-220, Thaklr. a. S . U Preziosc). and N Marchexsky 1979. Echinococcus granulosus: ovicidal activitx' of praziquantel and bunamidine h\drochloride. E.xp. Parasitol. 47: 131-133. Thompson, R C A 1986, Biology and systematics oi Echi- nococcus. Pages 5-43 in R. C. A, Thompson, ed., The biolog\ of Echinococcus and h\ datid disease. George .\llen and I nwin Press. London. SEED GERMINATION CHARACTERISTICS OF CHRYSOTHAMNUS NAUSEOSUS SSP. VIRIDULUS (ASTEREAE, ASTERACEAE) M, A. Khan', N. SankhUr, D. J. Wehcr', and E. D, McArthur' Abstract — Rubber rabhitbmsh (Chn/sotliamnus nauseosiis [Pallas] Britt. ssp. viriduhis) may prove to be a source of high-cjuality cis-isoprene rubber, but its establishment is limited by a lack of information on seed germination. Conse(}uently, seeds were germinated at alternating temperatures (5- 15, 5-25, 15-25, and 20-30 C) in light and dark as well as constant temperatmes (15-40 C with 5-C increments) to determine temperature response. Seeds were also germinated in solutions of polyethylene glycol 6000 (0 to -5 bar), salinity regimes (1, 17, 51, and 86 niM) at all the above-mentioned temperatm-es to determine salinity and temperature interaction. The hormones GA, (0, 2.9. 29.0, and 58. 0 uni) and kinetin (0, 4.7, 23.5, and 47.0 um) were used to study their effect on overcoming salt- and temperature-induced germination inhibition. Seeds of C. nauseo.sus ssp. viridtilus were very sensitive to low tempera- ture. Best germination was achieved at 25 and 30 C, liut these seeds also germinated at a higher temperature (35 C). The seeds of rabbitbrush germinated at both constant and alternating temperatures. Light appears to play little or no role in controlling germination of the seeds of rubber rabliitbrush. However, seeds of rabbitbrush were sensitive to salinity, and seed germination was progressiveK inhibited b\ increase in salt concentration, although a few seeds still germinated at the highest saline level. Progressively higher concentrations of polyetlnlene gKcol also progressively inhibited germination. Suppression of seed germination induced b\ high salt concentrations and high temperatures can be partially alle\ iated by the application of either GA3 or kinetin. Chrysothamnus nauscosus (Pallas) Britt. ssp. viridulus (Hall) Hall & Clements is the largest and most robust of the appro.ximately 20 subspecies of C nauscosus (rubber rabbit- brush) (Hall and Clements 1923, Anderson 1966). Anderson (19S6a) has reduced C. nau- seosus ssp. viridulus to a variety of C. nau- scosus ssp. consimiJis. In this report we have chosen to maintain it at the subspecies level because several characteristics such as higher rubber content (Ostler et al. 1985), size, habi- tat, and distribution distinguish it from ssp. consimilis. Rubber rabbitbrush as a species occurs widely west of the one hundredth meridian in North America, barely extending from the United States north into Canada and south into Mexico. Rubber rabbitbrush is usually 30-230 cm in height, having several erect stems from the base and with moderately flex- ible leafy branchlets (McArthur et al. 1979a, McMinn 1980). Subspecies viridulus, how- ever, may grow to 3 m in height in the alkaline valleys of west central Nevada and eastern California. The several subspecies of this perennial shrub show considerable variation in distribu- tion and adaptation (Hall and Clements 1923, McArthur et al. 1979a, Anderson 1986b), in phenolic plant chemistry and palatability to browsing animals (Hanks et al. 1975), in rela- tion to gall-forming insects (McArthur et al. 1979b, Wangberg 1981, McArthur 1986), in seed-germination characteristics (McArthur, Jorgensen, and Weber, unpublished), and in rubber and resin content (Hall and Good- speed 1919, Ostler et al. 1986, Weber, McArthur, and Hagerhorst, unpublished). The potential of this taxon for rubber produc- tion was first suggested by Hall and Good- speed (1919) and has recently been rated as promising by Ostler et al. (1986). Results of nuclear magnetic resonance analyses demon- strate that Chrysil, the rubber from rabbit- brush, is a high-(iuality cis-isoprene molecule type rubber. It may be that the rubber pro- duction from guayule {Parthenium argen- tatum) and rubber rabbitbrush, both com- posite family shrubs, could be processed through the same industrial plant. Rabbit- brush is adapted to a wide range of soils in- cluding those that are alkaline and to temper- Department of Botany, University of Karachi. Karachi .32 Pakistan. "Department of Botany, University of Joclhpnr, Jodhpiir, India. ''Department of Botany and Range Science, Brigham Young University, Provo, Utah S4602 ■"USDA Intermountain Research Station, Forest Service. Provo, Utah 84601. 220 April 1987 Kuan etal.: Chrysothamnus Germination 221 Table 1. Eflect of NaCl aiul alti-riiatiiiu ttMuperatures on the percent of germination of Chn/fiotlKminus tuiti- seosus ssp. viridtihis seeds in light. Tabu-: 2. Effect of NaC;l and alternating temperatures on the percent of germination of Chrysothamnus nau- seosus ssp. virkhihis seeds in dark. NaCl (mM) Alternating temperatures (C) 5-15 5-25 15-25* 20-30* NaCl (mM) Alternating temperatures (C) 5-15 5-25 15-25* 20-30* 0 53.3" 67.8-' 90.0' 94.4' 0 54.5" 54.5" 91.8" 96.3" 17 49.2" 46.6'" 80.0'' 79.8'" 17 57.2" 53.2" 83.8" 73.2'" 51* 35. 1" 34.0'" 40.2^ 53.2^- 51** 33.3'" 26.6'" 42.6' 54.5' 86* 12.0'' 12.0^ 35.9^ 18.62' 86** 16.0'" 9.3' 34.6' 27.9'' "Values with the same letter in a column are not significantly different as determined by the Duncan multiple-range te.st at a .0.5. *Tw()-way analysi.s of variance indicates (1) NaCl inhibitory above 17 mM, and (2) alternating temperatures (1.5-25 and 20-30 C) are stimulatory. ^^^ Values with the same letter in a column are not significantly different as determined b\ the Duncan multiple-range test at a .05. *Two-way analysis of variance indicate.s (1) NaCl inhibitory above 17 mM, and (2) alternating temperatures (1.5-25 and 20-30 C) are stimulatory. ate climates, whereas guayule grows in frost- free or nearly frost-free areas (Johnson and Hinnian 1980). Rubber rabbitbrush acces- sions have up to 6.5% rubber content (Hall and Goodspeed 1919, Ostler et al. 1986, We- ber, McArthur, Hagerhorst, unpublished) and will resprout when tops are harvested (Young etal. 1984). Additional information will be required on germination of rubber rabbitbrush seed if it is to be used as a commercial crop for rubber production. Obtaining young rabbitbrush plants by rooting fresh cuttings is difficult (Ev- erett et al. 1978). Transplanting nursery seedlings is a reliable method, but direct seeding should be more economical. How- ever, direct seeding methods have received little study. Stevens et al. (1981) reported that C. nanseosus seed germination declines from 80 to 14% from the second through the fifth year of warehouse storage. In another report, Stevens et al. (1986) demonstrated the impor- tance of proper seed placement in the soil for germination and seedling vigor. Deitschman et al. (1974) reported that eight collections of C. nauseosus had an average of 63% seed viability. Sabo et al. (1979) reported a maxi- mum germination of 76% for C. nauseosus ssp. consimilis. Our objective was to investigate effects of simulated environmental factors and growth regulators on germination characteristics of rabbitbrush accession with high rubber yield potential to obtain more information on seed physiology. This information could be useful in growing plants from seeds. M.ATERIALS AND METHODS Seeds of Chrysothamnus nauseosus (Pallas) Britt. ssp. viriduhis were collected in the fall of 1984 from plants growing at Palmetto, Es- meralda Co. , Nevada (collected by McArthur, Weber, and Sanderson). This population has large plants up to 3 m in height. Seeds were separated from inflorescences and stored at 4 C in paper bags. Germination tests were car- ried out in 9-cm-diameter glass petri dishes containing Whatman No. 1 filter paper moist- ened with 5 ml of distilled water or other test solutions. Three replicates of 25 randomly se- lected seeds each were used for each treat- ment. Seeds were considered to be germi- nated with the emergence of the radicle. To determine the effect of temperature on germination, we used growth chambers to ob- tain alternating regimes of 5-15, 5-25, 15-25, and 20-30 C based on a 24-hour cycle, where the higher temperature (15, 25, and 30 C) coincided with a 12-hour light period, and the lower temperature (5, 15, and 20 C) coin- cided with the dark period. Seeds were also germinated under constant temperatures ranging in 5-C increments from 15 to 40 C. The petri dishes were randomized at each temperature regime. We studied the light re- quirement by comparing germination in petri dishes in the dark (covered in a box) with germination in petri dishes in the light. Seeds were germinated in distilled water, 17, 51, and 86 mM NaCl solution under the above- mentioned temperature regimes. Water stress was imposed by adding polyethylene glycol (PEG-6000) to distilled water to give a wide range of osmotic potential (from 0 to -0.5 mpa) (Michel and Kaufman 1973). Several concentrations of GA3 (0, 2.9, 29.0, and 58.0 um), and kinetin (0, 4.7, 23.5, and 47.0 um) were applied. We recorded ger- mination every day for three days and calcu- lated the rate of germination using an index of 222 Great Basin Natur.\list Vol. 47, No. 2 60 T 50 .. 40 ■- Velocity of og germination 20 -■ 10 .. 0.0 17 51 NaCI (mM) ■ 5-25 C B 5-15 C M 15-25 C E3 20-30 C Fig. 1. Rate of germination (velocity of germination) of seeds of Chnjsothamntis natiseostts ssp. viridiilu.s at alternating temperatures and three concentrations of NaCl. ■ 40 C n 35 C n 30 C m 25 C n 20 C m 15C 17 51 NaCI (mM) Fig. 2. Percent germination of seeds oi' Chnjsothamntis nauseosus ssp. viriduhis at constant temperatures and three concentrations of NaCl. April 1987 Khan etal: Chrysothamnus Germination 60 T 223 Velocity of ^q germination ■ 40 C m 35 C m 30 C m 25 C n 20 C s 15C NaCI (mM) Fig. 3. Rate of germination (velocity of germination) of seeds QiChn/sotlidnttuts naii.seostis ssp. viridulus at constant temperatnres and three concentrations of NaCl. germination velocity = G/t, where G = per- centage of seed germinated at one-day inter- vals, t = total germination period (Khan and Ungar 1984). Percentage germination data were trans- formed (Arcsin percent) before statistical analyses. The treatments were compared with Duncan's multiple range test. Results and Discussion Light and temperature effects. — Rab- bitbrush seeds were germinated in light and dark conditions at constant and alternating temperatures. There were no differences in germination response between seeds germi- nated in light or in dark (Tables 1, 2), suggest- ing that the seeds were insensitive to light. Alternating temperature regimes of 20-30 and 15-25 C yielded ma.ximum germination. Substantially less germination occurred in the 5- 15 and 5-25 C temperature treatments (Ta- bles 1, 2). Rate of germination estimated by using an index of germination velocity indi- cated that rates of germination at 15-25 and 20-30 C were twice as high as those oi 5-15 and 5-25 C treatment (Fig. 1). These results indicate that low night temperatines inhibit both the rate and the final germination per- centages. Sabo et al. (1979) reported that seeds of C nauseosus ssp. consimilis germi- nated well with a peak percentage of 76% at alternating temperatures of 13-27.5 C. Alter- nating temperatures of 13-27.5 C (8 h) and 23-27.5 G (16 h) gave the best range re- sponses, with germination times increasing slightly at the cooler temperature (Sabo et al. 1979). Rabbitbrush seed germinated substantially at constant temperatines including 35 G (a = .05) (Fig. 2). Sabo et al. (1979) reported that germination of C. nauseosus ssp. consimilis was inhibited at a temperature above 27.5 G. The rate of germination of C. nauseosus ssp. viridulus was maximum at 30 G and decreased with either an increase or decrease in temper- ature (Fig. 3). At 40 and 15 G, the velocity of germination was significantly reduced. Salinity' effect. — NaGl salinity signifi- cantly inhibited (a = .05) the rabbitbrush seed germination at a concentration of 86 mM (Tables 1, 2). Rates of germination were signif- icantlv reduced (a ^ .05) at higher salinity (51 and 86 mM NaGl) (Table 1, Fig. 3). No inter- action of light, temperature, and salinity was observed to affect seed germination. This spe- 224 Great Basin Naturalist Vol. 47, No. 2 Germination (%) Fig. 4. Percent germination of seeds oi Chnjsotham- nus tiau.seostis ssp. viridtilus at different levels of mois- ture tension. cies has been reported to be highly salt toler- ant (Sabo et al. 1979, Roundy et al.' 1981), but our study indicated that it behaved like typical glycophytes at the germination stage. In natu- ral field situations, seed germinates and seedlings could become established when precipitation dilutes natural high-salt concen- trations. Once established, plants can tolerate relatively harsh conditions. In natural stands, C. nauseosus ssp. viridulus grows in alkaline valleys (Hall and Clements 1923). Moisture Stress Rabbitbrush seed germination was progres- sively reduced as the moisture tension in- creased to -5 bar (Fig. 4). At -5 bar treat- ment, less than 10% of seeds germinated compared to 85% in control. Seeds of C. nau- seosus ssp. consimilis showed 34% germina- tion at -7 bar treatment (Sabo et al. 1979). Plant Growth Substances Various concentrations of kinetin and GA3 promoted germination of C. nauseosus ssp. viridulus as compared to nontreated control. NaGl (>51 mM) significantly (a = .05) inhib- ited germination. This salt-induced inhibition was reduced by the inclusion of various con- centrations of kinetin and G A3 in the medium (Fig. 5). Inhibition of seed germination induced by high salt concentration could be alleviated by application of GA3 (Ungar and Binet 1975, Boucaud and Ungar 1976, Ungar 1977, Ungar 1984, Khan and Ungar 1985) and cytokinins (Boothby and Wright 1962, Odegbaro and Smith 1969, Kaufmann and Ross 1970, Ross GermJnation(%) 50 23 5 Kinetin (fjM) Germination(%) 50 GA (jiM) Fig. .5. Effect of kinetin and gibberellic acid on the germination of seeds oi Cliryfiotlia)nnus nauseosus ssp. viridulus in relation to three concentrations of NaCl. and Hegartv 1980, Bozcuk 1981, Khan and Ungar 1985). High salt concentrations induce dormancy in seeds of many plant species (Hydecker 1977). Boucaud and Ungar (1976) found that salinity depresses seed cytokinin levels but not the concentration of GA3. However, dor- mancy induced by salinity, which may be sim- ilar to that caused by emergence-restricting seed coats, was broken by an application of GA3 but not by kinetin (Ungar 1977). Khan and Ungar (1985) reported that GA3 and kinetin can break salt-induced dormancy in Atripk'x triangularis, suggesting that when exposed to salt stress, seeds of various species behave differently in response to exogenous application of growth substances. Inhibition of germination caused by high temperature (40 C) can also be partially allevi- ated by addition of GA3 and kinetin in the medium (Table 3). In addition, GA3 and kinetin also partially alleviated the inhibitory effects of salt and higher temperature on ger- mination. April 1987 Khan etal: Chrysothamnus Germination 225 Table 3. Velocity of germination and germination per- centage at 40 C with NaCl, Ga^, and kinetin. Velocity of Treatment germination 7c germination Control 15.0 27.9 NaCl (51 mM) 10.0 16.0 GA3 (20 ppm) 21.7 43.9 Kinetins (10 ppm) 24.3 47.9 Salt + GA, 19.0 36.0 Salt + kinetins 27.3 47.9 Acknowledgements This study was facilitated by funds from the National Science Foundation Grant PCM- 8320462 (to Weber and McArthur); Grant INT-8403768 (to Khan and Weber); and by Pittman Robertson Wildlife Habitat Restora- tion Project W-82R (cooperators, Utah Divi- sion of Wildlife Resources and USDA Forest Service, Intermountain Research Station). The use of trade, firm, or corporation names in this paper is for the information and conve- nience of the reader. Such use does not consti- tute an official endorsement or approval by the U.S. Department of Agriculture of any product or service to the exclusion of others that may be suitable. Literature Cited Anderson, L C 1966. CytotiLxonomic stndies in Chn/sothamntis (Asterede, Compositae). Amer. J. Bot.53: 204-212. 1986a. Key and atlas for the genus Chnjsotluim- nus. In: E. D. McArthur and B. L. Welch, comps.. Proceedings — symposium on the biology of Artemisia and Chrysothamnus. USDA Forest Service, Gen. Tech. Rep. INT — , Ogden, Utah. 1986b. Synipatric subspecies of Chnjsothamnus naiiseosus. In: E. D. McArthur and B. L. Welch, comps.. Proceedings — symposium on the biology oi Artemisia and Chrysotliamnus . USDA Forest Service, Gen. Tech. Rep. INT — , Ogden, Utah. BOOTHBY, D , .AND S. T C Wright 1962. Effect of kinetin and other growth regulators on starch degrada- tion. Nature 196: 389-390. BouCAUD, J., ANDl. A. Ungar 1976. Hormonal control of germination under saline conditions of three halo- phvtic taxa in the genus Suaccla. Phvsiol. Plant. 37:143-148. BOZCUK. S 1981. Effects of kinetin and salinity on germi- nation of tomato, barlev and cotton seeds. Ann. Bot. 48: 81-84. Deitschman.G H , K R Jorgensen. and.\ P Pllmmer 1974. Chrysothamnus Nutt. — rabbitbrush. Pages 326-328 in C. S. Schopmeyer, tech. coord.. Seeds of woody plants in the United States. USDA Forest Serv ice, .\gric. Handbook 450. EvERErr. R L .and F E Clements 1919. A rubber plant survey of western North America. Univ. Calif Publ.Bot. 7: 1-278. Everett. R. L . R D Meeuwig. and J H. Robertson. 1978. Propagation of Nevada shrubs by stem cut- tings. J. Range Manage. 31: 426-429. Hall, H M.. and F E. Clements. 1923. The phyloge- netic method in ta.xonomy. The North American species of Artemisia, Chrysothamnus. and Atriplex. Carnegie Inst, of Washington, Publ. 326. Hanks, D. L., E. D. McArthur, A P Plummer. B C. Giunta. and a. C. Blauer 1975. Chromato- graphic recognition of some palatable and unpalat- able subspecies of rubber rabbitbrush in Utah. J. Range Manage. 28: 148-149. Hydecker, W 1977. Stress and seed germination: an agronomic \iew. Pages 237-282 in A. A. Khan, ed., Physiology and biochemistry of seed dor- mancy and germination. North-Holland, Amster- dam. Johnson. J D . andC. W Hinman 1980. Oils and rubber from arid land plants. Science 208: 460-464. Kaufmann, M. R., and K. J. Ross. 1970. Water potential, temperature, and kinetin effects on seed germina- tion in soil and solute systems. Amer. J. Bot. 57: 413-419. Khan, M. A., and 1. A. Ungar. 1984. The effect of salinity and temperature on the germination of polymor- phic seeds and growth of Atriplex triangularis Willd. Amer. J. Bot. 71: 481-489. 1985. The role of hormones in regulating the ger- mination of polymorphic seeds and early seedling growth at Atriplex triangularis under saline condi- tions. Physiol. Plant. 63: 109-113. McArthur, E D 1986. Specificity of galls on Chrysothamnus nauseosus subspecies. In: E. D. McArthur and B. L. Welch, comps.. Proceed- ings— symposium on the biology of Artemisia and Chrysothaninus. USDA Forest Service, Gen. Tech. Report INT—, Ogden, Utah. McArthur, E D , A. C Blauer, A P Plummer, and R. Ste\ens 1979a. Characteristics and hybridization ofimportant intermountain shrubs. 111. Sunflower family. USDA Forest Service Research Paper INT-220. McArthur, E. D., C. F Tiernan, and B. L Welch. 1979b. Subspecies specificity of gall forms on Chrysothamnus nauseosus. Great Basin Nat. 39: 81-87. McGlNNES. W. G 1979. Guayule {Paiihenium argen- tatum ) a potential source of natural rubber for Egypt. Pages 411-424 in A. Bishay and W. G. McGinnes, eds., Advances in desert and arid land technology and development. Harwood Acad. Publishers, New York. McMlNN. J E. 1980. California shrubs. University of Cali- fornia Press, Berkeley. Michael. B E . and M R Kaufmann. 1973. The osmotic potential of polyethylene glycol 6,000. Plant Phys- iol. 51: 914-916. Odegbaro. O. a , AND O. E Smith 1969. Effects of kinetin, salt concentration and temperature on germination and early seedling growth of Lactuca .safiva L. J. .\iner. Soc. Hort. Sci. 94: 167-170. 226 Great Basin Natur.\list Vol. 47, No. 2 Ostler, W K. C M. McKell, and S White. 1986. Chnjsothamnus nauseosus : A potential source of natural rubber. In: E. D. McArthur and B. L. Welch, conips., Proceedings — symposium on the biology of Ai-femisia and Chnjsothaninus. USDA Forest Service Gen. Tech. Rep. INT — , Ogden, Utah. Ross, H. A . ANDT. W. Hegarty 1980. Action of growth regulators on lucerne germination and growth un- der water stress. New Phytol. 85:495-501. RoiiNDY, B A., J A. Young, and R. A Evans. 1981. Phe- nology of salt rabbitbrush (Chnjsofliamnus nau- seosus ssp. consimilis) and greasewood {Sarcoba- tus venniculattis). Weed Sci. 29: 445-454. Sabo, D C, G. V. Johnson, W. C. Martin, and E F. Aldon. 1979. Germination requirements of 19 species of arid land plants. USDA Forest Service, Res. Pap. RM-210. Stevens, R., K R Jorgensen, and J N Dams 1981. Vi- ability of seed from thirty-two shrub and forb spe- cies through fifteen vears of warehouse storage. Great Basin Nat. 41: 274-277. Stevens. R . K R Jorgensen. J N D.^vvis. and S B Mon- sen. 1986. Seed pappus and placement influences on white rubber rabl)itbrush establishment. In: E. D. McArthur and B. L. Welch, comps.. Proceed- ings— symposiinn on the biology oi A t-temisia and Cl}njsoth(imnits. USDA Forest Service, Gen. Tech. Rep. INT—, Ogden, Utah. Ungar, I. A 1977. Salinity, temperature and growth reg- ulator effects on seed germination of Salicornia curopca L. Acjuat. Bot. 3: 329-.3.35. 1984. Alleviation of seed dormancy in Speroulaha marina. Bot. Gaz. 145: 33-36. Ungar, I. A, and P. Binet. 1975. Factors influencing seed dormancy in Sper^ularia media (L.) C. Presl. Aquat. Bot. 1:45-55. Wangberg, J. K. 1981. Gall-forming habits oi Aciurina species (Diptera: Tephritidae) on rabbitbrush in Idaho. J. Kansas Entomol. Soc. 54: 711-732. Young.J. A .R A Evans, AND B L Kay 1984. Persistence and colonizing ability of rabbitlirush collections in a common garden. J. Range Manage. 37: 373-377. DEVELOPMENT AND LONGEVITY OF EPHEMERAL AND PERENNIAL LEAVES ON ARTEMISIA TRIDENTATA NUTT. SSP. W^CMIINGENSIS' Richard F. Miller" and Leila M. Shiiltz' Abstract — Big sagebrush {Artemisia tridentata Nutt.) is one of the most successful plants in the Great Basin based on its abundance and wide distribution. The development of dimorphic leaves may be an important mechanism attributing to its adaptive and competitixc abilities. Development, persistence, and proportions of ephemeral and perennial leaveson Wyoming big sagebrush [Artemisia tridentata Nutt. ssp. iri/o/JiingcH.si.v) were studied for two years. The large ephemeral leaves are the first to develop in early spring. As early developing ephemerals mature and stems elongate, new ephemeral and perennial leaves develop in the a.xes of these large ephemerals. Perennial leaves expanded in the summer of their first growing season, persisting on the shrub until their abscission during simimer drought of the second growing season. Plants maintained 33% of their leaf weight through the winters of 19S5 and 1986. Active leaf and stem growth occurred at soil water potentials above ().2 MPa. During the past 100 years, big sagebrush (Artemisia tridentata Nutt.) has increased in abundance and distribution in many areas of the Great Basin. Success of this shrub throughout its range may be attributed in large part to the dimorphic development of ephemeral and perennial leaves. Caldwell (1979) suggests that the ability of the plant to maintain part of its leaf crop through the win- ter enables it to begin growth and utilization of water in early spring. Development and maintenance of large ephemeral leaves during optimum growing conditions may also in- crease photosynthetic potential by reducing mesophvll resistance (DePuit and Caldwell 1973). Development and persistence of ephem- eral and perennial leaves on big sagebrush growing in the Great Basin are poorly imder- stood. Little work is available on timing and position of ephemeral leaf development in re- lation to perennial leaves. Confusion exists regarding the longevity of ephemeral and perennial leaves. On big sagebrush growing east of the Rocky Mountains, mature leaves remaining on the plant over winter are dis- carded soon after spring growth resumes (Di- ettert 1938, Branson et al. 1976). On three subspecies of big sagebrush growing in the Great Basin, Miller et al. (1986) reported overwintering leaves remained green on the plant through the subsequent growing sea- son. These leaves senesced during initiation of summer drought, concurrent with abscis- sion of the large ephemeral leaves. A clear picture of big sagebrush leaf development will enhance our understanding of why this plant is the most abundant and widespread shrub throughout the Great Basin. Objectives of this study were: (1) define the sequence and de- velopment of ephemeral and perennial leaves, (2) measure retention of the different leaf types, (3) define the proportion of both leaf types occurring on the plant, and (4) relate the developmental secjuence to soil moisture. Materials and Methods Research was conducted at the Squaw Butte Experimental Range in southeastern Oregon on the northern fringe of the Great Basin. The study site was located in a Wyo- ming big sagebrush-Thvu-ber's needlegrass (Ai-temisia tridentata ssp. wijomingensis Nutt. -Stipa thiirberiana Piper) habitat type. The 40-year mean annual precipitation is 300 mm. The studv was conducted from Septem- ber 1984 through August 1986. In November of 1984 and 1985 three branches from each of five Wyoming big sage- brush plants were marked with metal tags. At the terminus of each branch all leaves were marked with a dot of black indelible ink, counted, and leaf length measured. On 1 Orep>ii AyrKiiltiiral Experiment Station Technical Paper No- S121. "Eastern Orendii AKricultural Research Center, Squaw Butte Station. Oregon State University. Burns, Oregon 97720. Curator ot the Intermountain Herbarium, Department of Biology , Utah State University, Lx>gan, Utah 84322. 227 228 Great Basin Naturalist Vol. 47, No. 2 April 1984 and 1985, prior to leaf elongation, all marked leaves were counted and leaf length measured. Measurements on marked leaves were continued at two-week intervals throughout both growing seasons. Detailed notes and drawings were also made on current year's leaf and stem development. Ten Wyoming big sagebrush plants were randomly selected for measurement of pro- portion of leaf types in 1985. These plants were harvested just past peak leaf develop- ment, when leaf growth and vegetative stem elongation had terminated and early signs of senescence were visible. Each plant was placed in a large plastic bag, brought into the lab, and leaves separated into four categories. The four leaf categories were 1984 perennial, 1985 perennial, lobed ephemeral, and non- lobed ephemeral occurring on reproductive stems. The 1984 and 1985 perennial leaves were easily differentiated by color, the cur- rent year's crop being lighter. Leaves were then dried for 48 hours at 60 C and weighed. Soil water and soil temperature measure- ments were recorded concurrently with phe- nology. Soil water was measured gravimetri- cally at two depths, 2-20 cm and 20 cm to the hardpan, which varied from 40 to 50 cm. Soil moisture release curves for each of the two layers sampled were developed to convert percent soil water to soil water potential. Soil temperatures were measured with a soil ther- mometer at 15-cm and 30-cm depths. Results Big sagebrush is a semi-evergreen shrub, maintaining a portion of its leaves through the winter. All perennial leaves marked in the fall of 1984 and 1985 persisted through the win- ter, spring, and early summer, senescing at the onset of summer drought in late July of 1985 and 1986, respectively. Leaf longevity totaled 12 to 13 months, with no leaves per- sisting through two winters. Winter-persis- tent leaves, which only partially elongated during the previous growing season, did not reinitiate elongation the subsequent spring. The large ephemeral leaves are the first to develop early in the spring from small leaf buds, less than 1 mm in length, at the stem apex. Leaf elongation begins in early spring forming tight clusters or fascicles at stem apices prior to stem elongation. When stems current yea stem gro previous season stem growth Fig. I. Current year's growth near peak development with large early ephemeral leaves (epl), later-developing ephemerals (ep2), and winter-persistent leaves (p). If stems do not elongate, separation of individual leaf clus- ters is more difficult to distinguish. Last year s winter- persistent leaves are not included. begin to elongate, ephemeral leaves are alter- nately positioned along the stem (Fig. 1). These early ephemeral leaves are the largest leaves on the plant. As spring progresses and the early ephemeral leaves near maturity (full leaf extension), a small cluster of leaves begins to develop in the axes of ephemeral leaves. These leaf fascicles contain both ephemeral and perennial leaves. Lateral leaf fascicles are properly termed "short shoots. " Each short shoot fascicle is subtended by a long shoot and large eral leaf (Fig. 1). Later-developing ephemeral leaves are smaller than the early ephemerals but larger than the fully expanded perennial leaves. Not all fascicles contain this smaller ephemeral leaf, while some contain two. Ephemeral leaves on the reproductive stems are nonlobed and have no short shoot fascicles in their axes. At the onset of drought, both the previous season perennial and large, early- developing ephemeral leaves begin to senesce. Later-developing ephemerals, in- cluding nonlobed leaves, persist during the initial phase of leaf fall, senescing in late sum- April 1987 Miller, Shultz: Artemisia Leaves 229 20 , £ 15 I- < o ^ (r> 10 S . J DATE Fig. 2. Relationship of various stages of leaf development and senescence with soil water at 20 to 40+ cm; early ephemerals (epl), ephemerals in axes of epl (ep2), pre\ious year's perennials (pi), current year's perennials (p2), nonlobed ephemerals on reproductive stems (epr). Plant growth and soil water data deri\ ed from 1981, 1982, 1985. and 1986. mer and fall. By November only the cm-rent crop of perennial leaves persists. At initiation of plant growth, soil tempera- tures were 9 and 5 C at both 15- and 30-cm depths in 1985 and 1986, respectively. The majority of leaf and stem development oc- curred when soil water potentials were above —0.2 MPa in the wettest soil layer (Fig. 2). All the large ephemeral leaves were developed at this time. Once soil water potential in the wettest soil layer dropped below —0.2 MPa, elongation of primary vegetative stems termi- nated and leaf growth declined at a rapid rate. At soil water potentials between —0.2 MPa and —1.5 MPa, reproductive stems continued to elongate and short shoots elongated to a small degree. Limited growth of current year's perennial leaves continued, while pre- vious season's winter-persistent leaves and the early large ephemerals began to senesce. All stem elongation and leaf growth termi- nated when soil water potentials dropped be- low — 1.5 MPa. The majorit\ of winter-persis- tent leaves of the previous growing season and early ephemerals senesced within a two-week period. The relative proportion of perennial leaves remained nearly constant during the two growing seasons. At peak leaf development, leaf biomass on vegetative stems was 38 ±4% previous season's perennial leaves (1984), 24 ±3% ephemeral leaves, and 37 ±3% cur- rent season s perennial leaves (1985) (at P = 0.90). Total leaf biomass consisted of 87 ±6% lobed leaves and 13 ± 6% nonlobed leaves on the reproductive stems. Reproductive stem numbers were highly variable across the 10 shrubs, with nonlobed leaf biomass ranging from 2.5 to, 28. 5%. Discussion Our observations of leaf development and longevity of Great Basin big sagebrush do not fully agree with those reported by Diettert (1938) and Branson et al. (1976). We conclude that the life span of winter-persistent leaves is approximately one year and that they persist 230 Great Basin Naturalist Vol. 47, No. 2 through a second growing season, senescing at the onset of summer drought rather than at the beginning of the growing season. Branson et al. (1976) concluded that only 1 of 10 leaves marked on big sagebrush persisted on the plant (although this may be an artifact of mark- ing leaves prior to or during the early stages of perennial leaf development). Their data indi- cate the plant maintains only 10% of its leaf numbers during the winter. On plants grow- ing in the Great Basin, we found Wyoming big sagebrush retained 33% of its leaves, on a weight basis, throughout winters of 1985 and 1986. This compares more closely with Miller et al. (1986) where 53% of the leaf weight (lobed leaves only) senesced at the onset of summer drought. Had their data included nonlobed ephemerals on the reproductive stems, percent leaf weight lost may have ap- proached 66%. Early large ephemerals were first of the current year s leaf crop to abscise. Ephemeral leaves developed in the axes of the large ephemerals senesced throughout the summer and fall. This agrees with Diettert's (1938) observation that those leaves produced early in the year may be shed before the hot, dry periods of summer, although there is continu- ous but less conspicuous fall throughout the year. The majority of plant growth, with the ex- clusion of reproductive stems, occurred at soil water potentials above — 0.2MPa. This is con- sistent with plant growth and soil water data collected in 1981 and 1982 for three subspe- cies of big sagebrush (Miller et al. 1986). DePuit and Caldwell (1973) reported photo- synthesis in big sagebrush is inhibited by moderate plant water stress. Persistence of winter leaves allows ever- green plants an earlier start in utilizing nutri- ents and soil water than herbaceous or decidu- ous shrub species which have little or no leaf area displayed at the beginning of the growing season. Soil water is depleted more rapidly early in the growing season around isolated Wyoming big sagebrush plants than around isolated plants of green rabbitbrush (Clirysothamnus viscidijlonis ssp. viscidi- floriis), as well as in plots containing only perennial grasses (Eastern Oregon Agricul- tural Research Center data file). This is pri- marily due to a larger transpiration surface displayed early in the growing season. Suc- cess of big sagebrush may also be partially related to the display of numerous leaves dur- ing the cool season of the year prior to the development of moisture stress (Caldwell 1979). Leaf conductance of ephemeral leaves is higher than in persistent leaves (Eastern Oregon Agricultural Research Center data file), indicating photosynthesis per unit leaf area may be higher. The ratio of leaf surface to leaf weight is also higher for ephemerals than perennials (Ganskopp and Miller 1986), indi- cating the expense of resources used to de- velop the ephemeral leaf surface may be less than for persistent leaves. These large eral leaves enable the plant to effectively uti- lize resources during optimum growing con- ditions. When water becomes limiting, the plant responds by reducing its leaf surface area, abscising the large ephemeral and previ- ous season persistent leaves. ACKNOWLEDCMENTS The Eastern Oregon Agricultural Research Center, which includes the Squaw Butte Sta- tion and the Union Station, is jointly operated and financed by the Oregon Agricultural Ex- periment Station, Oregon State University, and U.S. Department of Agriculture, Agricul- tural Research Service. Literature Cited Branson, F A . R F Miller, and J S McQueen. 1976. Moi-sture relationships in twelve northern desert shrub communities near Grand Junction, Colo- rado. Ecology 57: 1104-1124. Caldwell, M M 1979. Physiolo.gy of sagebrush. Pages 74-85 in The sagebrush ecosystem: a symposium, Utah State University, Logan, Utah, 1978. DePuit, E. J., and M. M Caldwell 1973. Seasonal pat- tern of net photosynthesis o{ Artemisia triclentata. Amer. J. Bot. 60: 426-4.35. DiETiERT, R 1938. The morphology oi Artemisia triclen- tata Nutt. Lloydia 1: 3-74. Gan.skopp, D.. and R. F. Miller. 1986. Estimating leaf area of big sagebrush from measurement of sap- wood. J, Range Manage. 39: .338-340. Miller, R F , P. S. Doescher, T. Svejcar, and M. R. Haferkamp 1986. Growth and internal water status of three subspecies oi Artemisia tndentata. Pages .347-352 in E. D. McArthur and B. L. Welch, eds.. Symposium on the biology of Artemisia and Chrysuthamntis. Gen. Tech. Rep. INT-20(). Ogden, Utah. PYGMY RABBITS IN THE COLORADO RIVER DRAINAGE C, L. Pritchett', J. A. Nilsen', M. P. Cofit'cir, and H. D. Sinitli' Abstract — A range extension of the pygni\- rahl)it, Braclujlagus idahucnsis, into tlie Colorado River basin and a hypothesis as to its route of emigration. The following report records the occur- rence of Brachylagus idahoeusis (Merriani) beyond its published range in the Bonneville Basin. The southeastern record of Occurrence is 4.8 km NE Panguitch, Garfield Co. (Stephenson 1966). Holt (1975) reported "an isolated population about 15 miles south of Fish Lake on the Parker Mountain. On 7 July 1982 Michael Coffeen, Utah Division of Wildlife Resources, collected a pygmy rabbit ca 16 km S of the Fish Lake Ranger Station in Wayne Co., T28S RIE S14, elev. 2,379 m, and on 12 September 1982 Mark Oveson, un- aware of Coffeen s specimen, reported seeing pygmy rabbits 4.8 km W of Loa, T28S RIE S3, elev. 2, 183 m Wayne Co. (personal communi- cation). Since then six live individuals plus two skulls have been collected from the Parker Mountain region of Awapa Plateau. The live animals were used for preparing karyotypes and saved as voucher specimens. This is the first published report of pygmy rabbits outside the Pleistocene Lake Bon- neville (Columbia River) drainage. Awapa Plateau is part of the Fremont River water- shed that eventually enters the Colorado River. Two of the specimens were females and two were males, but sex was not determined on the other three. Selected mean measure- ments (in millimeters) of two females and two males compared with means from Brachyla- gus reported bv Janson (1946) in parentheses were as follows: Tot. L. 251, 218 (291) (278); Tail L. 20, 18 (17) (17); H.F. 66, 63 (70) (70); Ear. 52, 56 (50) (51). Means of greatest length of skull (N = 8) compared with means of the same measurement on skulls from 23 pygmy rabbits from Dubois, Idaho, are respectivelv 51.8 (S.E. = 0.72) to 49.8 (S.E. - 0.54). The voucher specimens and the comparison skulls of the Idaho rabbits were deposited in the mammal collection of the Life Science Mu- seum, Brigham Young University. The rab- bits and their sign (burrows and pellets) were essentially confined to tall big sagebrush, Artemisia tridcntata , stands in shallow washes. This is consistent with other observa- tions on pygmv rabbit habitat as reported bv Merriam (189i), Grinnell et al. (1930), Orr (1940), and Green and Flinders (1980). Ac- cording to some of the older ranchers in Loa, these "little rabbits ' have been there as long as they can remember and have been exten- sively hunted along with cottontails and black- tailed jackrabbits (personal communication, 1984). " Assuming that big sagebrush is essential for these mammals, there are three possible routes of dispersal that might have been used by the pygmy rabbit to emigrate from the Great Basin to the Awapa Plateau (Fig 1). One route would be to exit the Great Basin and Sevier River by following the valley formed by Peterson Creek, near Sigurd, Sevier Co., up to Awapa Plateau. This is essentially the same route now used for Utah Highway 24. The other two routes leave the Great Basin from NE Iron Co. Janson s (1946) distribution map indicates a population of pygmy rabbits 24 km NW of Parowan, Iron Co. Individuals from this or nearby popidations could have emi- grated east through Buckskin Valley and Dog Valley into the Sevier River drainage SW of Circleville, Piute Co. From that point the most direct route would have been to follow the Sevier River down to its junction with East Fork of the Sevier River north of Cir- cleville, thence east past Kingston along the DepartTTit-nt ul ZuoIohn . Brigham Young University. Provo, Utah 84602. -Utah Division of WildUle Resources, 622 N. Main, Cedar Citv, Utah 84720 231 232 Great Basin Natufl\list Vol. 47, No. 2 ANPETE Known pcpdatcns iL Hi^toRical W LURRQnt PQCpcsed dispc-RSo/ rc ...... //A-e/y __- AlteRnate BEAVER Fig. 1. Locations ol historic and present pygmy rabbit populations in the study area and routes of proposed emigration. lower portion of East Fork of the Sevier River Otter Creek drainage north through Grass to Otter Creek. This route would then follow Valley to the Parker Mountain Range. Once April 1987 Pritcmett et al. : Pycmy Rabbits 233 into the Sevier River drainage near Circleville an alternate route might have followed the Sevier River south to Panguitch, the location of Stephensen's (1966) pygmy population, and on south along the river to its junction with Red Canyon. This route would then cross Paunsaugunt Plateau through Red Canyon and Coyote Hollow into Emery Valley, just north of Bryce Canyon National Park. The East Fork of the Sevier River flows through Emery Valley, a historic sagebrush commu- nity, to its junction with Otter Creek. From this junction pygmy rabbits could have fol- lowed the route previously suggested through Grass Valley to Parker Mountain. During the summer of 1986, we spent sev- eral days following the proposed routes look- ing for pygmy rabbits and pygmy rabbit sign. Both their pellets (they pile their tiny, hard pellets like pack rats) and burrows (entrance shape) are distinctive. We were able to find pygmy rabbits or their sign from Burrville, ca .8 km northwest of Parker Mountain, south through Grass Valley to just north of Otter Creek Reservoir where big sagebrush ends and cultivated land and pastures begin. Holt (1975) found a small population of pygmy rab- bits west of Otter Creek Reservoir. However, we were not able to find that population. The valley between Kingston and Otter Creek is narrow and very disturbed. One of the last large patches of big sagebrush along this 19- km route had just been plowed and harrowed which made it impossible for us to tell if pygmy rabbits were or had been there. We found no sign of pygmy rabbits from Sigurd to Burrville, and no pygmy rabbits or sign were observed through Emery Valley. Because of these observations, we feel the route from northeastern Iron Co. to the junction of the East Fork of Sevier River, up to Otter Creek and north through Grass Valley to Parker Mountain to be the most logical dispersal route for this group of lagomorphs. We appreciate the comments and helpful suggestions made by Drs. W. Z. Lidicker, J. L. Patton, and David Ribble, all from the Museum of Vertebrate Zoology, University of California, Berkeley. Literature Cited Green.J S .AND J. T. Flinders. 1980. Habitat and dietary relation.ships of the pvgmv rabbit. J. Range Man- age. 33: 136-142. Grinnell. J , J Dixon, AND J. M Linsdale 1930. Verte- brate natural history of a section of northern CaU- fornia through the Lassen Peak Region. Univ. California Publ. Zool. 35. 594 pp. Holt. R G. 1975. Ta.\onomy and distribution of cottontail rabbits, genus Sijlvil(i} Fig. 10. Bootherium bombifrons, USU 3529, posterodorsal view. Bar represents 10 cm. rounded in cross section and are unflattened and most importantly, there is a very abrupt dorsally near their bases. An exostosis and posteroventral slope of the dorsal outline of cranial sulcus are lacking, and the frontals the skull posterior to the horn cores. This between the horn cores are smooth. Perhaps, sloping area is a very diagnostic feature on the 248 Great Basin Naturalist Vol. 47, No. 2 Fig. 11. Bootherium bombifrons, USNM 215066 (cast), original ANSP 2994, posterodorsal view. Bar represents 10 Fig. 12. Bootherium bombifrons, BYUG 834, posterodorsal view. Bar represents 10 cm. type specimen of B. bombifrons; the horn cores seem to be placed on the summit of the skull very similar to the condition in goats and sheep, but unlike Syinbos (Fig. 11). Although the ventral part of this skull is abraded, sufficient detail is present to permit identification of the characteristic basioccipi- tal-basisphenoid area. In Bootherium the April 1987 Nelson, Madsen: Fossil Musk Ox 249 \ K V Fig. 13. Bootheriumsp. indet., IMNH 17124, right lateral view. Bar represents 10 cm. proximal end of the basisphenoid is dorsally deflected from the basioccipital at a very low angle (less than 20 degrees). In Symbos this deflection is greater than 35 degrees (White, personal communication 1984). A second Bootherium skull from Utah (BYUG 834) is quite similar to USU 3529 in most characteristics (Fig. 12). The single, ma- jor difference is in the length of the sloping skull cap posterior to the horn core attach- ment. In BYUG 834 this length is only about 90% of the length of USU 3529. However, this difference may be attributable to post mortem abrasion of the skull rather than to pathology, individual variation, or sexual dimorphism. Both Utah specimens (BYUG 834 and USU 3529) of Bootherium may now be assigned with certainty to B. homhifrons. They, but especially USU 3529, are almost identical to the type specimen of B. homhifrons in size and morphological characteristics. A second specimen of Bootherium in the Brigham Young University collections could not be lo- cated (Nelson and Madsen 1978), but photo- graphic evidence suggests that it too is B. homhifrons. UUVP 8532, described by Nel- son and Madsen (1978), also appears assignable to B. homhifrons, but post mortem abrasion of the specimen makes this latter identification more tenuous. A specimen, IMNH 17124, which was col- lected from Bannock Gounty, Idaho, and de- scribed by White (1985) as Bootherium sp., is difficult to place specifically (Fig. 13). It ex- hibits all of the characteristics of Bootherium homhifrons (see White 1985 for a descrip- tion), with the exception of the length of the skull cap posterior to the horn core attach- ment (Fig. 14). In IMNH 17124 the cranial cap slopes abruptly downward at a much greater angle than in B. homhifrons. In addi- tion, the length of the cranium posterior to the horn cores is 30% shorter than comparable specimens of B. homhifrons. This specimen may represent a pathological individual, a new species o( Bootherium, an individual vari- ant, or a sexual opposite from that of the type specimen of B. homhifrons. The gracile nature of this specimen suggests the latter choice, with IMNH 17124 representing a female. 250 Great Basin Naturalist .f*--- >?' Vol. 47, No. 2 B Fig. 14. A, Bootheriwn homhifrons, USNM 215066 (cast), original ANSP 2994, right donsolateral view; B, Bootherium sp. indet. , IMNH 17124, right dorsolateral view. Bar represents 10 cm. Summary In summary, we assert that UVP 083 is inseparable from Bootheriwn sargenti, which in turn is placed in synonymy with Syjnbos cavifrons. These are sexual dimorphic forms, and it is likely that the typical S. cavifrons specimens are males whereas the "B. sar- genti" forms are females. Bootherium homh- ifrons is a valid taxon and is probably not closely related to S. cavifrons. Acknowledgments We could not have completed this paper without the counsel and help of John White and Clayton Ray. Robert Purdy of the Smith- sonian Institution graciously loaned us casts of "Bootherium sargenti" and B. homhifrons, while John Neas of the University of Kansas furnished a cast of the Natural Trap specimen. Wade Miller (BYUG), Bill Akerston (IMNH), Greg Ostrander (KUVP), Dave Liddell (USU), Charles Repenning (USGS), Tim Smith (Alaska Fish and Game), and George Corner (Nebraska State Museum) made spec- imens in their care available for study. We also gratefully acknowledge the many discus- sions with other ovibovine enthusiasts includ- ing Jerry McDonald, John Neas, Dick Harington, John White, Clayton Ray, Lee Stokes, and George Corner. The financial support for this project was shared to some degree by the Utah Division of State History and DINOLAB, Salt Lake City, Utah, and Fort Hays State University, Hays, Kansas. Literature Cited Allen. J. A 191.3. Ontogenetic and other variations in musko.xen with a systematic review of the musko.x group, recent and extinct. Mem. Amer. Mus. Nat. Hist., n.s. 1: 103-226. Barton. J B 1976. A late Pleistocene local fauna from American Falls, southeastern Idaho. Unpublished thesis, Brigham Young University, Provo, Utah. Dawkins, W. B. 1867. Ovibos moschatus (Blainville). Proc. Roy. Soc. London 1.5: 516-517. 1872. The British Pleistocene Mammalia. Part V. British Pleistocene Ovidae, Ovibos moschatus. Paleontographical Soc. 25: 1-30. April 1987 Nelson, Madsen: Fossil Musk Ox 251 Gazin. C. L 1935. Annotated list of" Pleistocene Mam- malia from American Falls, Idaho. J. Washington Acad. Sci. 25: 297-302. GiDLEY, J. W 1908. Descriptions of two new species of Pleistocene ruminants of the genera OviJ)os and Bootherium, with notes on the latter genus. Proc. U.S. Nat. Mus. 34(1627): 681-684. Harlan, R. 1825. Fauna Americana. Anthony Finley, Philadelphia. 318 pp. Hay, O. p. 1915. Contributions to the knowledge of the Pleistocene of North America. Proc. U.S. Nat. Mus. 48: 515-575. 1924. The Pleistocene of the middle region of North America and its vertebrated animals. Carnegie Inst. Washington Pub. 322A. 385 pp. 1927. The Pleistocene of the western region of North America and its vertebrated animals. Publ. Carnegie Inst. Washington 322b. 346 pp. Hesse. C J 1942. The genus Bootherium, with a new record of its occurrence. Bull. Te.xas Arch. Paleon- tol. Soc. 14: 77-87. Hibbard. C. W., and F J Hinds 1960. A radiocarbon date for a woodland musk o.x in Michigan. Pap. Michigan Acad. Sci., Arts aixl Letters 45: 103-108. Hopkins, M L 1951. Bison (Gi^antobison) latifrons and Bison (Simobison ) allcni in southwestern Idaho. J. Mammal. 32: 192-197. 1955. Skull of fossil camelid from American Falls Bed area of Idaho. J. Mammal. 36(2): 278-282. Hopkins, M L , R Bonnichsen. and D E Fortsch 1969. The stratigraphic position and faunal associ- ates of Bison (Gigantohison)latifrons in southeast- ern Idaho, a progress report. Tebiwa 12(1): 1-8. Kurten. B., and E Anderson 1980. Pleistocene mam- mals of North America. Columbia University Press, New York. 442 pp. Leidy, J. 1852a. Remarks on two crania of e.xtinct species of ox. Acad. Nat. Sci. Philadelphia 6(3): 71. 1852b. Memoir on the extinct species of American ox. Smithsonian Contrib. Knowledge 5: 1-20. 1869. The extinct mammalian fauna of Dakota and Nebraska, including an account of some allied forms from other localities, together with a synop- sis of the mammalian remains of North America. J. Acad. Nat. Sci. Philadelphia, Ser. 2, 7: 23-472. Lonnberg. E 1900. On the structure and anatomy of the muskox {Ovibos moschatiis). Proc. Zool. Soc. London. 686-718. Lydekker. R 1885. Catalogue of the fossil Mammalia in the British Museum, part 2, containing the order Ungulata, suborder Artiodactyla. London. 314 pp. 1898. Wild oxen, sheep, and goats of all lands, living and extinct. London. 318 pp. McDonald, J N 1984. An extinct muskox mummy from near Fairbanks, Alaska: a progress report. Pages 148-152 in D. R. Klein, R. G. White, and S. Keller, eds.. Proceedings of the first international muskox symposium. Biol. Pop. Univ. Alaska Spec. Rep. 4. McDonald. H. G., and E. Anderson 1975. A late Pleis- tocene fauna from southeastern Idaho. Tebiwa 18(1): 19-37. Nelson, M E . and J H Madsen, Jr 1978. Late Pleis- tocene musk oxen from Utah. Trans. Kansas Acad. Sci. 81: 277-295. Osgood, W. H. 1905a. ScapJwceros tijrelli, an extinct ruminant from the Klondike Gravels. Smithsonian Misc. Coll. 48: 173-185. 1905b. Symbos, a substitute for Scaphoceros. Proc. Biol. Soc. Washington 18: 223-224. Ray. C E 1966a. The identity of Bison appalachicolus. Notulae Naturae Acad. Nat. Sci. Philadelphia 384: 1-7. 1966b. The status oi Bootherium brazosis. Texas Mem. Mus. Pearce-Sellards Ser. 5: 1-7. R\Y, C E., B N Cooper, and W S Benninghoff. 1967. Fossil mammals and pollen in a late Pleistocene deposit at Saltville, Virginia. J. Paleontol. 41: 608-622. Rhoads. S N 1895. Distribution of the American bison in Pennsylvania, with remarks on a new fossil spe- cies. Proc. Acad. Nat. Sci. Philadelphia 49: 483-502. RUTIMEYER. L 1867. Beitrage zu einer palaeontologis- chen Geschichte der Wiederkaurer, Zunachst an Linne's Genus Bos. Verhandl. Naturf. Gesel. Basel. 4: 299-354. Semken. H A , Jr . B B Miller, and J B Stevens. 1964. Late Wisconsin woodland musk oxen in associa- tion with pollen and invertebrates from Michigan. J. Paleontol. 38: 823-835. Stokes, W. L.. andG H. Hansen 1937. Two Pleistocene musk oxen from Utah. Proc. Utah Acad. Sci. 14: 63-65. White, J A 1985. Late Pleistocene musk oxen from southern Idaho. Tebiwa 22: 64-71. WiSTAR, C 1918. An account of two heads found in the morass, called Big Bone Lick, and presented to the Society, by Mr. Jefferson. Trans. Amer. Phil. Socn.s. 1:375-380. EFFECTS OF LOGGING ON HABITAT QUALITY AND FEEDING PATTERNS OF ABERT SQUIRRELS Jordan C. Pederson', R. C. Farentinos", and Victoria M. Littlefield^ Abstract. — In 1973 a timber harvest of ponderosa pine (Pinus ponderosa) was conducted in an area southeast of Monticello, Utah, that is inhabited by Abert squirrels {Schirus aherti). Abert squirrel dietary habits, foraging patterns, and population densities were compared in the timber harvest area and in an adjacent nonharvpsted area. Squirrel feeding patterns and preferences were visually determined by physical evidence of past feeding. Live-trapping and field-marking of animals were used to determine population density and trends in the two areas. Squirrels fed in only 26.3% of sampled plots on the timber harvest areas, while 42.7% of the uncut area plots showed use (P < 0.001). Trap days per catch were higher on the harvested area (P < 0.01). Similar differences in hvpogeous fungi feeding sites between the two study sites were also recorded (P < 0.01). Thus, clearcut timber harvest of ponderosa pine did negatively affect Abert squirrels. To minimize long-term effects on squirrels, timber should be harvested in small, selective blocks (< 20 acres) rather than in large-scale areas (> 50 acres) by clear-cut methods commonly employed by management agencies. Mammalian food habits studies have been conducted in several ways: ad libitum feeding of captive animals, fecal analysis, sacrificing free-ranging animals and inventorying the stomach contents, stomach pumping, and field observations of animals' feeding behav- iors. All methods have distinct advantages and disadvantages. Captive feeding allows control of the ani- mals' environment and quantitative/qualita- tive regulation of intake, but the results may not validly apply to wild populations. Shoot- ing or kill-trapping of individuals, together with subsequent stomach content examina- tion, assumes that a large enough sample has been taken to represent the food habits of that population. The removal of individuals from a small population may also be disadvanta- geous. The use of observational data is based on the assumption that the observations are representative of the natural habits and that all food items can be properly identified by the observer. In this study, food habits and preferences of free-ranging Abert squirrels iSciurus aberti) were determined by examin- ing physical evidence resulting from squirrel feeding. Such evidence is easily recognized and consists of ground litter disturbance (re- sulting from digging for fungi), ponderosa pine (Pinus ponderosa) cone removal and descaled cone litter, large numbers of termi- nal needle bunch clippings found under se- lected ponderosa pine trees, and debarked twigs from ponderosa pine branches (Peder- son et al. 1976). Abert squirrels (Sciunis aberti subspp. and Sciurus aberti kaibabensis) are dependent on currently available food items since they do not cache foods for later feeding (Keith 1956, 1965, Stephenson 1975). Their diet includes acorns (Quercus gambelii), ectomycorrhizal (hypogeous) fungi, and seeds of dwarf mistle- toe (Arceutliobium vaginatum). Ponderosa pine products include cambium ("inner bark") buds, cones, and seeds (Trowbridge and Law- son 1942, Keith 1956, 1965, Reynolds 1966, Larson and Schubert 1970, Heidmann 1972, Patton 1974, 1975, Stephenson 1975, Ras- mussen et al. 1975). The abundance and growth of many of the foods consumed by Abert squirrels are affected by weather condi- tions. The current study was undertaken to deter- mine whether timber harvest of ponderosa pine affects the availability of Abert squirrel foods (e.g., inner bark, cone seeds, fungi, etc.). Effects of timber harvest on squirrel densities, foraging patterns, movements, and/ or time-energy budgets were also examined. Objectives of the study were to: ^Utah Division of Wildlife Resources, 111.5 North Main, Spriiigville, Utah 84663. -693 South Broadway, Boulder, Colorado 80.306. University of Minnesota, Morris, Minnesota 56267. 252 April 1987 Pederson et al. : Abert Squirrels 253 1. Quantify dietary changes on a seasonal basis. 2. Correlate dietary changes with food item availability. 3. Determine how seasonal changes in diet and food item availability affect foraging patterns. 4. Analyze relative energy content of vari- ous food items, i.e., calorie content of ponderosa pine seeds vs. inner bark vs. buds, etc. Study Area The study area is in southeastern Utah on the Monticello Ranger District of the Manti- LaSal National Forest. Lying in the Bulldog- Verdure drainages of the Abajo Mountains, it is approximately 12 k (8 mi) southeast of Mon- ticello, Utah. In 1973 the Bulldog area was part of a timber harvest program by the U.S. Forest Service. The adjacent Verdure area served as a nonharvested control in a three- year Utah Division of Wildlife Resources study conducted to determine the short-term effects of timber harvest on Abert squirrels (Pederson et al. 1976). The Verdure and Bull- dog sites, each 56 ha (140 ac) in size, were studied simultaneously. Methods and Procedures For both the harvested and unharvested ar- eas, two types of food-related data were col- lected: (1) data on actual squirrel food use, and (2) data that reflected potential food available. 1. Data on actual Abert squirrel food use was obtained quarterly (April 1977- Decem- ber 1979) from 300 circular, random-sampled, lO-m" plots on each study area. Descaled pon- derosa pine cones, peeled ponderosa pine twigs, hypogeous fungi digs, use of dwarf mistletoe, and other feeding evidence were counted and recorded for each plot. Information was also collected on the mmi- ber of plots in which any feeding activity oc- curred on either area. The food item used was also recorded. Foods eaten by Abert squirrels were collected and tested for nutrient and caloric content. Foods were tested for percent moisture, Kjeldahl determination for protein, ash content, and Soxhlet extraction of lipids as described in the Official Methods of Analysis manual (1975). 2. Potential food available (i.e., current- year production of food items) was obtained by surveying 300 randomly selected plots each September and estimating production of ponderosa pine cones and Gambel oak acorns. These production estimates were tied to the food-use plots in the following manner: The closest ponderosa pine tree and Gambel oak tree to each food-use plot were observed through 7 x 35 binoculars. Cones or acorns on a quarter of the tree were counted and multi- plied by four to obtain an estimate of the current year's cone and acorn production. These production estimates were converted into a class code using the following key: Acorn and Ponderosa Pine Cone Production Key Class Prod. est. /tree (cones or acorns) 1- 26- 25 50 51- 100 101- 200 201 401 601 400 600 800 801-1,000+ Data were also collected on the amount of ground and litter disturbance caused by log- ging activity that occurred between 1973 and 1975. Litter depth was recorded on every tenth plot for both logged and unlogged areas when the ground was free from snowcover. This was converted into a class code as follows: Litter Depth Key (pine needles to mineral soil) Class Depth (cm) 0 none (bare ground) 1 1- 5 2 6-10 3 11-16 4 17-20 + Live-trapping and field observation tech- niques were used to aid in the evaluation of responses of squirrels to timber harvest. Squirrels were trapped using Tomahawk live traps. No. 203, 6 x 6 x 24 inches (Tomahawk Live Trap Company, Tomahawk, Wisconsin). The traps were positioned throughout the stud\' areas in eight locations most often fre- quented by squirrels. These areas were deter- mined by the presence of recent squirrel sign, nest locations, and actual observations of squirrels. Traps were placed in known or sus- 254 Great Basin Naturalist Vol. 47, No. 2 Table 1. Utah Abert squirrel food use data, 1977 through 1979. Year Area Month Ponderos pine chps no. Use % Fungi digs no. Use % pine peeled cones no. Use % Mistletoe Use % 1977 Bulldog July .58 59 0 0 39 40 0 0 Sept. 206 64 46 14 70 22 1 T Dec. 58 59 0 0 39 40 1 T Verdure July 467 76 91 15 57 8 0 0 Sept. 67 21 125 40 124 39 1 T Dec. 57 75 5 6 15 19 1 T 1978 Bulldog Feb. 140 100 0 0 0 0 0 0 April 264 96 5 2 6 2 1 T July 189 72 62 23 13 5 0 0 Sept. 238 100 Dec. 396 100 Verdure Feb. 131 100 0 0 0 0 0 0 April 486 100 0 0 1 T 0 0 July 183 39 280 60 3 0.5 3 0.5 Sept. 197 100 Dec. 285 100 1979 Bulldog Feb. 276 100 April 301 100 Verdure Feb. 287 100 April 351 100 pected centers of squirrel activity to establish home ranges (Hayne 1949). These activity centers were determined during a previous study (Pederson et al. 1976). Each trap was baited with both roasted peanuts and peanut butter. Each squirrel trapped was placed in a Plexiglas cone and then anesthetized with methoxyflurane (Metofane, Pitman-Moore, Inc., Fort Washington, Pennsylvania) using Barry's (1972) method on gray squirrels. The anesthetized squirrel was removed from the cone for measuring and tagging. Sex, age, weight, rectal temperature, tail length, total length, length of hind foot, ear and ear tassel length (if present), coloration, presence of parasites,, and any abnormalities were recorded. Parasites were collected for later identification. A careful record was kept on the time required to relax, time under, and recovery time from anesthesia. While the animal was still anesthetized, it was numbered with aluminum rabbit tags (National Band and Tag Co.) placed through each ear and secured with 3/8-inch (.94-cm) celluloid colored washers for later field and in-trap identification. A backup identification system insured future identification in case of tag loss; it consisted of a colored collar, made from TY-RAP CABLE ties (#TY-525 M. man- ufactured by Thomas Betts Co., Elizabeth, New Jersey), which was fastened around the squirrel's neck. Each collar was factory num- bered as an additional aid in identifying recap- tured squirrels. Results and Discussion Food-Use Data A comparison of overall feeding activity be- tween the two study areas during the two years shows that squirrel feeding occurred in 26.3% of the harvested Bulldog plots. Feed- ing was recorded in 42.7% of the nonhar- vested Verdure plots. The difference is signif- April 1987 Pederson ET AL. : Abert Squirrels 255 Table 2. Utah Abert squirrel trapping record, 1977-1978. Bulldog Verdure New Trap days New Trap days squirrels Total Trap per Trap days scjuirrels Total Trap per Trap days Month caught catches days new catch per catch caught catches days new catch per catch 1977 April 7 9 58 8.28 6.44 14 15 58 4.14 3.86 July 1 2 42 42.00 21.00 4 10 52 13.00 5.20 September 1 1 24 24.00 24.00 2 4 24 12.00 6.00 December 3 6 72 24.00 12.00 2 18 72 36.00 4.00 Total 12 18 196 16.33 10.88 22 47 206 9.36 4.38 1978 February 0 4 36 0 9.00 0 1 36 0 36.00 April 4 6 21 5.25 3.50 1 9 21 9.00 2.. 33 September 1 10 32 10.00 3.20 6 17 32 5.33 1.88 December 0 21 22 0 22.00 0 2 22 0 11.00 Total 5 41 111 22.20 2.36 7 29 111 15.85 3.82 Two-vear summary 17 59 307 18.05 5.20 29 76 317 10.93 4.17 icant at the P < 0.01 level (Table 1). This difference is also significant when the data are compared separately by year. The lower inci- dence of feeding activity in the area where ponderosa pine was harvested shows that some degradation of Abert squirrel habitat has occurred. The difference in feeding activity suggests lower population numbers and ap- parently lower recruitment of young in the Bulldog area. Squirrel movement from Bull- dog to Verdure for feeding was documented. Evidence of lowered population numbers in the Bulldog area is shown in both the higher number of trap days required for catching new squirrels and in lower total squirrel catches (Table 2). Feeding activity in both areas was of four specific types: ponderosa pine bark (needle bunch clips), ponderosa pine seeds (cones), dwarf mistletoe, and hypogeous fungi (digs). Data collected during the study show the ma- jority of the feeding was on ponderosa pine inner bark or cambium tissue (Table 1). This contrasts with other reports that twig feeding occurs mainly during winter months (Keith 1965, Stephenson 1975, Rasmussen et al. 1975). Frequent use of ponderosa pine seed was recorded only in 1977 and coincided with a very large cone crop (Table 1). Dwarf mistle- toe was used only in trace amounts. Stephen- son (1975) also reported that squirrels in Ari- zona used very little mistletoe. The use of ectomycorrhizal fungi was highest during July and September and was a direct reflection of summer precipitation (Table 1). A significantly higher number of feeding activity occurrences of hypogeous fungi were recorded for the uncut Verdure area. Fungi digs in the Bulldog area were 176, with 549 at Verdure. This difference is significant at the P < 0.001 level. Hypogeous fungi grow beneath a layer of ponderosa pine needles having a depth greater than 5 cm. Bulldog litter depth greater than 5 cm was present in only 23.3% of the plots, while this depth at Verdure oc- curred in 40.2%. This is also the percent hy- pogeous fungi digs found between the two sites (Table 1). Bulldog plots show 15.9% bare ground and Verdure 8.2%. Disturbance to ground cover bv logging activity was found in 38.4% of the plots examined (N'= 1,250). The opening of the upper canopy cover by timber harvest and accompanied logging activity has removed and reduced the litter cover and depth, thus reducing the microclimate neces- sary for production of hypogeous fungi, a sought-after and preferred food of the Abert squirrel. Stephenson (1975) reports that fungi were the "most important item on an annual basis, by volume and frequency of occur- rence. He found fungi in the diet every sea- son of the year, comprising as much as 91.9% of the summer diet. In addition, hypogeous fungi grow only on the roots of live ponderosa pine. Logging that kills the root system will also obviously cause the loss of this food source to Abert squirrels (Ure and Maser 1982). 256 Great Basin Naturalist Vol. 47, No. 2 Table 3. Chemical and caloric content on Abert sciuirrel foods in Utah, 1977-79. Date Moisture Protein Fats & oils Ash Calories collected Food item % % % % perg 1977 22 April Pipo* staminant cone 71.92 4.46 4.84 4,07 22 April Pipo seed 36.89 4.05 5.47 7,95 4 July Pipo cambium 44.12 4.62 7.65 4„34 4 July Pipo seed 8.77 9.48 11.59 4,63 4 July Mistletoe 56.74 6.60 2.14 10,. 52 22 Sept. Mistletoe 59.14 6.23 2.40 4.63 22 Sept. Boletus 87.99 25.06 5.03 9.68 22 Sept. Fairy ring 72.76 17.75 6.74 .34.32 22 Sept. Cantlarelaceae 72.. 35 13.79 1.72 25.23 22 Sept. Russiila 87.61 16.61 5,. 50 16.14 22 Sept. Pipo seed 62.44 5.06 11.89 31,22 3 Nov. Pipo seed 19.76 6.43 11.08 14.14 5,479.0 2 Dec. Mistletoe 54.69 6.73 1.16 4.48 2,586.1 2 Dec. Pipo cambium 47.74 2.07 3.40 10.16 2,454.4 1978 20 Feb. Pipo cambium Bulldog 48.08 1.65 3.84 8.20 4,155.9 Verdure 52.21 1.56 5.39 5,04 4,212.9 16 April Pipo cambium Bulldog 44.68 1.80 4.59 9.34 4,039. 5 Verdure 51.28 2.40 3.93 6.89 3,889.0 16 April Pipo mistletoe 60.13 7.24 2.22 5.76 4,669.5 29 May Pipo cambium (Bulldog) Feed tree 47.85 2.10 4.51 5.05 4,146.0 Nonfeed tree 48.33 2,09 4.22 7.80 4,195.3 Pipo buds 76.70 7.29 3.. 36 3.01 4,384.9 Pipo mistletoe 62.30 6.60 1.91 5.16 4,999.2 Juos mistletoe 60.61 8.51 2.16 13.06 4,195,3 4 July Pipo cambium (Bulldog) Feed tree 48.97 2.20 6.91 8,68 3,932,0 Nonfeed tree 46.92 1.78 5.41 9,21 3,724,9 Pipo mistletoe 64.92 5.45 1.36 5.30 4,793.0 22 Sept. Pipo cambium (Bulldog) Feed tree 51.90 2.70 2.80 9.30 — Mistletoe 59.74 5.20 1.15 4.83 Acorns 46.63 5.53 .04 1.28 4,220.0 30 Dec. Pipo cambium (Bulldog) Feed tree 43,34 2.34 .85 2.84 3,765.0 Nonfeed tree 49.66 2.41 1.87 2.41 3,955.0 1979 11 Feb. Pipo cambium (Bulldog) Feed tree 51.23 2.83 1.13 6.38 4,150.0 Nonfeed tree 51.23 2.68 .81 9.44 3,860.0 1 April Pipo cambium (Bulldog) Feed tree 53.86 2.56 1.78 5.58 4,498.0 Nonfeed tree 55.29 2.38 1.72 5.48 4,254.0 *Pipo - ponderosa pine ^ Pinus ponderosa The difference in feeding activity might be accounted for in lower population numbers and lower recruitment of young in the Bulldog area or a movement from Bulldog to Verdure for feeding. Food Chemical Analysis The moisture content of Abert squirrel foods ranged from a low of 8. 77% in ponderosa pine seed to a high of 87.99% in boletus fungi April 1987 Pederson etal.iAbert Squirrels 257 (Table 3). Ponderosa pine inner and outer bark showed a 49.30% moisture content for the study period (range = 43.34-55.29%). Mistletoe was the most consistent in percent moisture with a mean of 59.8 and a range of 54.69-64.92. Protein expressed on a dry-matter basis was highest in the fungi species (Boletus spp. aver- aged 25.06%; Marasmius oreades, 17.75%; Cantorelaceae, 13.79%; and Rtissida spp., 16.61%). These high protein levels for fungi are consistent with the Abert squirrel food habits study by Stephenson (1975). South- western dwarf mistletoe was relatively low in percent protein with a mean of 6.30 and a range of 5.20-7.24 (Table 3). Ponderosa pine cambium (inner bark) was very low in percent protein. Thirteen samples collected during the study period yielded a mean of 2.28% (range = 1.56-4.62%) (Table 3). These data are similar to those of 1.5-3.2% reported by Pederson and Welch (1985). In- ner bark, long thought to be the mainstay of the Abert squirrel diet, had a very low protein level (Table 3). Stephenson (1975) found inner bark in the diet throughout the year, but in significant quantities only in winter months. During very dry summers we found that feed- ing activity was as high as 76% on ponderosa pine inner bark (Table 1). The high moisture level of inner bark (averaging 49.30%) may account for its use as a water source in the diet. A study by Stephenson and Brown (1980) shows an annual mortality of 66% in a year with snowcover of 10 cm or more for 85 days. Their finding shows a positive correlation of the number of days of snow depth greater than 10 cm with the annual mortality rate of Abert squirrels in Arizona. During these periods of 10 cm or more of snow, squirrels were forced to eat only bark with its low protein content when higher protein foods such as fungi were unavailable for use. If deep snow lasted long enough, the squirrels could develop a severe nitrogen deficiency that could greatly in- crease the mortality rate (Pederson and Welch 1985). During snow-free months if hy- pogeous fungi habitat is reduced, this source of protein is unavailable to squirrels and the population declines. Squirrel Weights The weights of squirrels differed between areas. Those captured in the Bulldog timber harvest area weighed an average of 658.8 grams; those from Verdure averaged 670.8. Males weighed 640.2 grams and 653 grams, respectively. These data do not show signifi- cant statistical differences but suggest a trend to better body condition on the nonharvested Verdure area. Ectoparasites Captured squirrels were combed and exter- nal parasites collected. Two species of flea were recovered and identified. On 21 April 1977 a female Monopsijllus eiimolpi was col- lected from an adult male Abert squirrel cap- tured in the Verdure area. The same species was also found on another adult male Verdure squirrel on 2 July 1977. On 8 September 1977 a large male HystricliopsyUa dippiei was re- moved from an adult female squirrel trapped in the Bulldog study area. During the same time period an adult female Abert squirrel was captured, and a male and female Derma- centor andcrsoni were removed from her ears. The presence of external parasites did not appear to affect body condition or health of Abert squirrels on either area. Acknowledgments We acknowledge the help of the following Utah Division of Wildlife Resources (UDWR) personnel: Homer D. Stapley, Albert W. Heggen, F. Clair Jensen, Robert N. Hasenyager, Laurie Seamons, Richard Schultz, and Darris Jones. We also extend thanks to Kirk Heldquist, Ray Johnson, and F. M. Whitaker. Funding for this study was provided by the National Science Foundation and the Utah Division of Wildlife Resources. We also thank Dr. John M. Hill and Paul A. Savello of the Brigham Young University De- partment of Food Science and Nutrition for their help in the analysis of the food items collected and Dr. Vernon J. Tipton for the identification of external parasites collected. We also express our gratitude to Linda Wilder and Aurelia and Mary Ann Pederson for their help with field data collection. Literature Cited Barry, W L 1972. Methoxyflurane: an anesthetic for field and laboratory use on squirrels. J. Wildl. Manage. 36(3): 992-993. 258 Great Basin Naturalist Vol. 47, No. 2 Hayne, D. W 1949. Two methods for estimating popula- tion from trapping records. J. Mammalogy .30(4): 399-411. Heidman, L. J. 1972. An initial assessment of mammal damage in the forests of the southwest. USDA Forest Service, Rocky Mt. For. and Range E.xpt. Stn., Fort Collins, Colorado. Research Note RM- 219. 7 pp. Keith. J. O. 1956. The Abert squirrel (Sciurus aberti aberti) and its relationship to the forests of Ari- zona. Unpublished thesis, University of Arizona, Tucson. 106 pp. 1965. The Abert squirrel and its dependence on ponderosapine. Ecology 46: 150-165. Larson, M. M., and G. H. Schubert. 1970. Cone crops of ponderosa pine in central Arizona, including the influence of Abert squirrels. USDA Forest Service Research Paper RM-58. 15 pp. Official Methods OF Analysis. 1975. Page 821 in 12th ed. Association of Official Analytical Chemists, Washington, D.C. Patton, D R 1974. Estimating food consumption from twigs clipped by the Abert squirrel. USDA Forest Service, Rocky Mt. For. and Range Expt. Stn., Fort Collins, Colorado. Research Note RM-145. 12 pp. 1975. Abert squirrel cover requirements in south- western ponderosa pine. USDA Forest Service, Rocky Mt. For. and Range E.xpt. Stn., Fort Collins, Colorado. Research Note RM-281. 3 pp. P.^TTON, D R . R L. Wadleigh, and H G Hudak 1985. The effects of timber harvesting on the Kaibab squirrel. J. Wildl. Manage. 49: 14-19. Pederson, J C . R N Hasenyager, and A W Heggen. 1976. Habitat requirements of the Abert squirrel (Sciurus aberti navajo) on the Monticello District, Manti-LaSal National Forest of Utah. Utah Div. Wildl. Res. Publ. No. 76-9. Pederson. J G, and B L. Welch. 1985. Comparison of ponderosa pines as feed and nonfeed trees for Abert squirrels. J. Chem. Ecol. 11: 149-157. Rasmussen, D. I., D E. Brown, and D Jones. 1975. Use of ponderosa pine by tassel-eared squirrels and a key to determine evidence of their use from that of red squirrels and porcupines. Wildl. Digest. Ab- stract 10. Arizona Game and Fish Dept. 12 pp. Reynolds. H. G 1966. Abert s squirrel feeding on pinyon pine. J. Mammal. 47: 550-551. Stephenson. R L. 1975. Reproductive biology and food habits of Abert's squirrels in central Arizona. Un- published thesis, Arizona State L^niversity, Tempe. 66 pp. Stephenson. R L . and D E Brown 1980. Snow cover as a factor influencing mortality of Abert's squir- rels. J. Wildl. Manage. 44: 951-955. Trowbridge, A H.. and L L Lawson 1942. Abert squir- rel-ponderosa pine relationships at the Fort Val- ley Experimental Forest, Flagstaff, Arizona. (Mimeo. on file, Ariz. Coop. Wildl. Res. Unit, Tucson.) 38 pp. Ure. D C . and C Maser 1982. Mycophagy of red- backed voles in Oregon and Washington. Cana- dian J. Zool. 60: 3307-3315. PARASITES OF THE CUTTHROAT TROUT, SALMO CLARKI, AND LONGNOSE SUCKERS, CATOSTOMUS CATOSTOMUS, FROM YELLOWSTONE LAKE, WYOMING R. A. Heckmann and H. L. Chint:;" Abstrxct. — Twenty-five cutthroat trout (Salnio clarki) and eight longnose suckers (Catostonius catostomus) from Yellowstone Lake, Wyoming, were collected and examined for parasites in 1985. Cutthroat trout had at least six different species of parasites that included both protozoans and helminths. The greatest numlier of parasite species on one fish was nine. Parasites added to the known list for cutthroat trout from Yellowstone Lake, Wyoming, were; Myxosoma sp. , Diphijllobothrium ditremtim. Diphtjllubothriuin dendriticum, Diplostumiim baeri, and Posthodiplosto- 7num minimum. These data were compared with a previous survey (1971) and a checklist of parasites of cutthroat trout in North America. There are 17 species of parasites and two fungal species reported for cutthroat trout from Yellowstone Lake. Thchophrtja catostomi, Diplostomum spathaccum, and Lih(>thnum ditremtim Muscle, viscera 0 100 **DiphiiIl(>I)(>tlinum dendt iticum Muscle, viscera 0 100 **Diphyllobothnti?7i sp. Muscle, viscera 92 0 Digenea: Flukes **DipIostomuin baeri bucculcntum Retina of eye 0 100 **Posthodiplostomum minimum Viscera 0 8 C rcpidostomum farionas Intestine, gall bladder 95 100 Nematoda; Roundworms Bulbodacnitis scotti Intestine, pvloric caeca 95 100 Acanthocephala: Spinv Neocchinorhipiclms ruti b Intestine 0.4 0 headed worms Crustacea: Copepods Sabnincola sp. Gills, mouth 80 80 Hirudinea; leeches Piscicola sabnositica Gills, fins 18 16 UUnobdella sp. Fins 0.4 0 Fungi: Mycota Ichthyophonus sp. (Scipt 'olc^nia) Skin surface 0 8 *Heckmann, R. A. 1971. Parasites of cutthroat trout from Yellowstone Lake. Wyoming, Prog. Fish Cult. 33: 10.3-106. **larval stages, plerocercoids and metacercariae Table 4. Results of the survey for parasites of eight longnose suckers (Catostomtis catostomus) from Yellowstone Lake, Yellowstone National Park, Wyoming. Fish number Total length (mm) Weight (grams) Trichophrya Diplostomum* (metacercariae) Ligida intestinabs Comments (other parasites) 1 (male) 415 810 + + (Lens, 49) 1 (large) Ligula 13.5 x 420 mm (contracted, gonad com- pression and atrophy 2 (male) 436 1250 + + + (Lens, 100 + ) (Retina, 5-10) — Both lens and retina metacercariae 3 (female) 360 600 + + + (Lens, 100 + ) — Opaque lens 4 (male) 432 1250 + + (Lens, 20) — Opaque lens center 5 (female) 310 400 + + (Lens, 20) — — 6 (female) 412 800 + + (Lens, .39) — — 7 (male) 440 950 + + (Lens, 10) — — 8 (male) 420 815 + + (Lens, .35) 1 (large) Li<:,ida large *The lens form is D. spathaceum. 1000, a high-resolution scanning electron mi- croscope operating at 20 KV. Micrographs were taken at variable magnifications up to 10,000X. Similar steps or magnifications were duplicated for each specimen. A digital data keyboard entry system was used to incorpo- rate a permanent record on each micrograph. This record included the KV, magnification, micron bar, plate number, laboratory loca- tion, and specimen code number which was assigned to each plerocercoid. Eight longnose suckers collected with the cutthroat trout were examined for parasites using the same methods of study. Results and Discussion The results for the 1985 parasite survey for Salmo clarki fotmd in Yellowstone Lake are listed in Tables 1 and 2. The cutthroat trout April 1987 Heckmann, Chinc: Trout Parasites 263 ranged in total length from 200 to 400 mm and weighed from 250 to 525 grams. In comparison with the previous survey (Heckmann 1971), three protozoan species and the spiny-headed worm, NcoecJii- norhijnchus riitili, were not observed. These parasites were rarely present during the 1971 survey in which 250 fish were checked for parasites from 34 collection sites. Four para- sites were added to the current list (Table 3) following the 1985 survey. Cutthroat trout had at least six different species of parasites that included both proto- zoa and helminths (Table 3). The greatest number of different parasite species per fish observed was nine. Each parasite will be dis- cussed separately and compared with a check- list of parasites for cutthroat trout in North America. One limitation of this study was the number offish sampled representing only two sites on Yellowstone Lake. For the eight longnose suckers, Cato- stomiis catostomus, there were only three parasites observed (Table 4). These parasites are included in the discussion of cutthroat trout parasites. ThcJiuphnja Trichophnja is a genus of suctorian ciliate that commonly infests the gill surface of fishes throughout the world. Their usual mode of reproduction is by endogenous buds. Trichophnja clarki (Figs, la, lb) (Heck- mann 1970, Heckmann and Carroll 1985) was found on the gills of all cutthroat trout exam- ined from two sites on Yellowstone Lake, Yel- lowstone National Park, Wyoming, during the summer of 1985. Trichophnja catostomi (Heckmann 1970, 1971) was present on the gills of 100% of the adult longnose suckers examined from the same region (Tables 1,4). Butschli (1889) reported Trichophnja in perch (Ferca) and pike (E.so.v) from Europe and assigned the species name T. pisciiim. Davis (1937, 1942) was the first to report Tri- chophrya in the northern hemisphere. He assigned the names T. micropteri and T. ic- tahiri for the gill parasites of smallmouth black bass {Micropterus dolomieui ) and channel cat- fish ilctahirus punctatus), respectively. No name was given for Trichophnja in brook trout {Salvelitius fontinalis). He also was the first to suggest that it may have a pathogenic effect. Culbertson and Hull (1962) summa- rized all host records oi^ Trichophnja and sug- gested T. pisciitm be used for all species found in fishes. This suggestion was followed by Sandeman and Pippy (1967), who reported on four salmonids of Newfoundland infested with TricJioplinja. Hoffman (1967) stressed the need for further taxonomic study of tri- chophryan species and their symbiotic effects. For our study, light microscopy disclosed extensive pathology and an average of 7. 1% of the gill epithelium covered for longnose suck- ers due to T. catostomi. However, no damage was observed at the light level of magnifica- tion for T. clarki in cutthroat trout that had an equal area of the gill covered. Electron micrographs (Heckmann and Car- roll 1985) show damage to immediate host gill cells by both parasites, depicted by a reduc- tion and lack of mitochondria. Both parasites form attachment helices (0.52 x 0.04 \xm), which function for maintenance of parasite position on the host cell. Protozoan feeding on host tissue may be accomplished by use of necrotic gill tissue and mucus (Heckmann and Carroll 1985). Mtjxosoma During the 1985 survey one cutthroat trout had white cysts in the gills and skin that con- tained spores of a Myxosoma sp. Heckmann (1971) reported the presence of another myxosporean in the same sites. Myxosporeans are diagnosed when the par- asite is in the spore stage; opaque white cysts containing spores are visible on the fish. His- tozoic species, such as those of Myxosoma, usually form large cysts that can be seen with- out magnification. The identification of the myxosporean is customarily based on the spore morphology. Each spore contains a sin- gle sporoplasm and one to four polar capsules with coiled filaments (Hoffman 1967). The life cycle is direct, from fish to fish. This has been experimentally verified for Myxid- iinn, Chloromyxum, and Leptotheca, but not for other genera. After ingestion, the sporo- plasm leaves the spore, presumably pene- trates the intestine, and migrates to the final site, which is often very specific for a given species. The sporoplasm grows into a tropho- zoite, the nuclei divide, and the structure usually grows to produce many spores in a cyst or in a single trophozoite. If the cyst is near the surface, it may rupture and the spores will 264 Great Basin Naturalist Vol. 47, No. 2 :^ / ;?^ P'^ dP^J '•^/^ *'«'^> V.**.-*^'*;* Fig. la, lb. Trichophrya clarki (arrows) infesting the gills oi' Salino clarki. Note the large macronucleiis (n) and tentacles (t) characteristic of suctorian ciliates (400X). be freed in the water. If the cysts are internal, with two piriform polar capsules at the ante- the fish must die and disintegrate to free the rior end. The sporoplasm of the trophozoite spores (Hoffman 1967). does not contain an iodinophilous vacuole. Myxosoma is characterized by an oval spore Most of the known species are histozoic (HoflF- April 1987 Heckmann. Chinc: Trout Parasites 265 Fig. 2. Scanning electron micrograph of the anterior end of the plerocercoid stage oi DiphijUobothrium ditreum found in Salmo chirki (lOOX). man 1967, HofFman et al. 1965). DiphijUobothrium The plerocercoid stages of DiphijUoboth- rium parasitize salmonid fishes of Yellowstone Lake, Wyoming, and other lakes in Yellow- stone National Park. The parasites are found primarily in the cutthroat trout of Yellowstone Lake. DiphijUobothrium plerocercoids have been known in fishes of Yellowstone National Park since the first formal publication bv Leidy (1872). Linton (1891b) gave the first description of adult cestodes taken from peli- cans from the lake area. In the current study, plerocercoids of DiphijUobothrium were present in all cut- throat trout examined from two locations on Yellowstone Lake. Much confusion has evolved on the taxo- nomic relationship oi DiphijUobothrium spe- cies (Otto and Heckmann 1984). In our study. two species of DiphijUobothrium plerocer- coids were found: D. ditremum (Fig. 2) and D. dendriticum (Fig. 3), based on identifications by Ching and Andersen (personal communi- cation) and Andersen (1977). The life cycle oi DipJujUobotlirium species in Yellowstone cutthroat trout would be simi- lar to the life cycles of other DiphijUobothrium species. A typical life cycle would be as fol- lows: the egg, upon being deposited in the water, develops and hatches into a ciliated coracidium. The coracidium is then eaten by a crustacean host where it passes through the stomach wall and encysts in the tissues of the body cavity. The procercoid then develops within the crustacean. It remains within this host until the crustacean is eaten by a trout or other fish. The procercoid is then released upon ingestion and digestion of the crustacean. It migrates through the wall of the alimentary tract of the fish and develops into a plerocercoid. Great Basin Naturalist PLER L INP CT NORMAL leeu 711 Fig. 3. Scanning electron micrograph of anterior end of the plerocercoid stage of Diphyllobothriitm dendriticum found in Salmo clarki (lOOX). The organism encysts in the cecal wall, mesentery, or other abdominal organs. The plerocercoid continues to grow until it can break from the cyst and become free in the abdominal cavity of the fish. The plerocercoid may then migrate into the flesh and become encapsulated. Instances of plerocercoids en- tering the muscle have been found where part of the plerocercoid remains in the body cavity and part is in the muscle. Plerocercoids are never encysted if they are in the body cavity or in the muscle tissue. Plerocercoids of DiphyUobothriiim are re- leased from cysts or from muscle tissue of the fish when they are taken as food by the pri- mary host. The plerocercoid then develops into an adult cestode within the intestine of the primary host which is multiple for cut- throat trout. The primary hosts for the adult Diphyl- lohothrium in Yellowstone Lake are white pelicans {Pelicanus erythrorhynchus), Cali- fornia gulls (Lams calif ornicus), and Ameri- can mergansers (Mergiis merganser anieri- canus) (Otto and Heckmann 1984). The definitive hosts feed on infected fishes containing the plerocercoids. Information on man as a definitive host for DiphyllobotJirium continues to be published (Arh 1960, Margolis etal. 1973, Ohbayashi et al. 1977). Woodbury (1932) ingested eight small plerocercoids, some free and some encapsulated, in late summer of 1931. Fecal examinations were made through November, after which an anti- helmintic was taken in December. No evi- dence of infection was found. The experiment was repeated the next year. Six larger plero- cercoids (20-70 mm in length) were ingested. Fecal examinations for DiphyUobothriiim eggs were negative. Scott ingested plerocer- coids from Yellowstone Lake trout at various times with negative results (Post 1971). How- ever, Vik (personal communication 1985) in- gested plerocercoids and passed adult worms, indicating that human infections are possible. Crosby (1970) found that plerocercoids from Yellowstone Lake cutthroat trout resulted in viable, egg-producing adults in experimen- tally fed dogs. The physiological effect of the plerocer- April 1987 Heckmann, Chinc: Trout Parasites 267 4 Fig. 4. Diplostomum baeri, metacercariae (m) found in the retina (r) ofSabno clarki (400X). coids in the fish intermediate host were re- ferred to by Linton (1891a). These fish were described as being "emaciated." Other au- thors stressed this point, and today one may see such fish within the park. Heckmann (1971) noted that one fish taken from the west side of Yellowstone Lake near West Thumb had more than 400 plerocercoids. Nothing has been done to assess the effect of sublethal infections of this parasite on the fish from Yellowstone National Park, and quite heavy loads of plerocercoids may be carried by young, vigorous fish without harm. However, moderate loads of plerocercoids may be reducing the vitality of even the most vigorous fish (Post 1971). Recendy, Otto and Heckmann (1984) stud- ied the histopathological effects of the plero- cercoids on host fish in Yellowstone Lake. Eight cutthroat trout from the Yellowstone River and Yellowstone Lake were examined by histological technique and scanning elec- tron microscopy to determine the response of host tissue to the presence of diphyllobothriid larvae. Intact plerocercoids were encapsu- lated with connective tissue that was infil- trated with lymphocytes and macrophages. Granulomatous tissue that was fibrotic was also present. Pancreatic tissue was displaced in infections associated with the alimentary tract. The liver showed general necrosis with edema, and the spleen demonstrated a reduc- tion in cellularity and increased connective tissue. Testicular tissue compressed by an ad- jacent plerocercoid appeared to be in an oth- erwise normal stage of development. Necrotic myofibrils near encapsulated parasites were separated by edema and fatty infiltration. In general, DiphyUobothrium cordiceps did not appear to produce a serious debilitation of cutthroat trout (Otto and Heckmann 1984). Diplostomum: Metacercariae, Flukes Diplostomum baeri bucculentum (Fig. 4) and D. spathaceum (Fig. 5) are strigeid trema- todes (Diplostomatidae) with a metacercarial stage that causes a disease known as diplo- stomatosis or eye fluke disease of fishes (Doss et al. 1963). Because of the circumglobal na- ture of diplostomatosis as well as the severe 268 Great Basin Naturalist Vol. 47, No. 2 Fig. 5. Diplostomiim spathaceiim, metacercariae (m) found in the lens (1) oiCatostomus catostomus (400X). effects upon fish, amphibian, reptilian, bird, and mammalian lenses, much literature relat- ing to this trematode exists. Cutthroat trout from Yellowstone Lake had a 100% incidence of D. haeri, with some fish containing over 100 metacercariae per eye (Table 1). Fish are the most common second interme- diate hosts for Diplostomiim; however, infec- tions in amphibians, reptiles, and mammals have also been reported (Ferguson 1943). Once the cercariae have penetrated the sec- ond intermediate host, they lose their forked tails and migrate to the tissues of the eye where the metacercariae develop in 50-60 days (Erasmus 1958). Diplostomatosis can cause cataracts of the lens tissue, due to the presence of the metacercarial stage of this parasite. Visual acuity for infected fish can be slightly hampered or lost, depending on the number of worms present. In addition to vi- sual loss, fish show retarded growth and a change in food habits. In older fish, chronic infections produced subacute inflammatory reactions in the vitreous involving heterophils and eosinophils, and macrophages with in- gested lens material have been observed (Dollfuss 1949, Heckmann 1983, Falmeiri et al. 1976). There are many possible techniques to pur- sue concerning the control of diplostomatosis. One that shows promise is biological control by the use of a hyperparasite, Nosema stri- fi,eoidea (Microspora). Hussey (1971) reported the above species to be host specific for hyper- parasitizing sporocysts of Diplostomiim spathaceiim. Palmieri and Heckmann (1976) and Palmieri et al. (1976) substantiated Hussey s work for eye fluke infections offish in Utah. Reviews of the complete life history for Diplostomiim spathaceiim and D. haeri are found in Palmieri et al. (1976), Ching (1985), Davies (1972), and Hoffman and Hundley (1957). The pathological effects of Diplostomiim metacercariae upon the fish host are many. Examination of those fish blinded with cataract and containing a heavy burden of lar- val metacercariae revealed stunted growth (length, girth, and weight), abnormal feeding behavior (lack of response to visual stimuli), and decreased vital acuitv (Palmieri et al. April 1987 Heckmann, Chinc: Trout Par^^sites 269 Fig. 6. PustliudiptustoDiitin niiniiiiuiit. nictaccrcariae (m) toiind in the viscera ofSaJnio chirki i i(K).\) 1976, Heckmann and Palmieri 1978). Ashton et al. (1969) reported that larvae migrate to the eye via vascular-venous channels; he demonstrated that the lens, vitreous, or cor- tex of the eye may be substantially damaged. Ferguson (1943) reported that metacercariae could develop in the lens of a variety of experi- mentally infected vertebrate hosts including mammals. Thus, there is a potential human hazard for these parasites (Ashton et al. 1969). Ching (1985) clarified the differences be- tween the metacercariae of the two species of Diplostomum reported for this study. Posthodiplostomum The metacercariae were found in the vis- cera of only 8% of the examined cutthroat trout, Salmo clarki. An excellent review for this common fish parasite is found in Spall and Summerfelt (1969a, 1969b). Metacercariae have been found in all visceral organs but occur in abundance in the liver, spleen, kid- neys, mesenteries, sinus venosus, heart, and ovaries. Avault and Allison (1965) found that the heart, liver, and kidneys contained ap- proximately 79% of the total metacercariae in bluegill {Lcpomis Diacroclunis). Early literature concerning the classifica- tion oi PostJiodiplostomum minimum (Fig. 6) has been reviewed by Miller (1954), Hoffman (1958), Bedinger and Meade (1957), and Spall and Summerfelt (1969b). Metacercariae of the strigeid fluke, Posthodiplustomum minimum, the white grub, are reported in many American hel- minthological surveys of fishes. The metacer- cariae, first reported over a century ago, occur in abundance in many of the 100 species of North American fishes (Hoffman 1967). They are generally so nimierous in the liver, kid- ney, heart, and other viscera that many ob- ser\'ers have considered them to be histo- pathogenic. The pathogenicity of the larval stage is usually due to compression or occlu- sion of the \'ital organ. The occiurence of numerous metacercariae in visceral organs suggests deleterious effects on the well-being of the host and implicates Posthodiplostomum minimum as a cause of mortalit\ or moriiiditN to its host. Hunter (1937, 1940) stated that death resulted if suffi- cient liver or other visceral tissue were de- 270 Great Basin Naturalist Vol. 47, No. 2 stroyed by the metacercariae. Wild fish, with several hundreds of encysted metacercariae in the liver, sinus venosus, heart, and kid- neys, are often observed to suffer no obvious debilitating effects. Colley and Olsen (1963) found as many as 991 metacercariae per bluegill with metacercariae so dense as to be clumped en masse. Spall and Summerfelt (1969a) have observed 2,041 metacercariae in a bluegill from an Oklahoma reservoir. Mortality has been observed in the labora- tory following exposure of suitable host fish to high numbers of cercariae (Hunter 1937, Be- dinger and Meade 1967). Host reactions fol- lowing cercarial penetration include petechial hemorrhage at the site of invasion, followed by congestion of surrounding venules, local edema, and an aggregation of leucocytes at the point of entry, particularly the phagocytic elements (Spall and Summerfelt 1969b). Nutrition of the metacercaria involves transport across the cuticle. Oral feeding is impossible because the esophagus does not begin development until 8 days after penetra- tion and is not well developed until 17 days; intestinal caeca develop after 17 days (Spall and Summerfelt 1969b). After encystment (19 days), mortality infre- quently occurs. There is no experimental evi- dence to indicate mortality or other detrimen- tal effects from the occurrence of encysted metacercariae (Spall and Summerfelt 1969b). Compression of vital organs, such as gonadal tissue, needs to be further considered for this parasite. C repidostomiim: Flukes, Adult Stage In the 1985 survey all cutthroat trout were infected with C repidostomiim fa rionis. In the 1969-1970 survey, which included many more fish, 95% of the Salmo clarki were in- fected with the fluke (Heckmann 1971). The genus Crepidostomum is characterized by an elongated-oval to subcylindrical body. The oral suckers are terminal, surmounted anterodorsally by a half-crown, six-head papil- lae. The esophagus is short or moderate and the ventral sucker is in the anterior half of body. Characteristics of the life cycle are: adult in fish; oculate xiphidiocercaria in sphaerid clams; metacercaria in aquatic in- sects, usually mayflies, or amphipod crus- taceans (Hoffman 1967). Recent reviews of this fluke include Dollfus (1949) and Doss et al. (1964), while Amin (1982) and Hopkins (1931a, 1931b, 1934) hst keys to species. In relating the pathogenicity oiC repidosto- miim farionis to its host, Heckmann (1971) reported adult flukes in fingerling Salmo clarki often occupying the lumen of the gall bladder. Biilbodacnitis: Roundworm, Nematoda A consistent member for the parasitofauna oiSaJiyw clarki from Yellowstone Lake, Wyo- ming, was Biilbodacnitis. Most adult ne- matodes offish live in the intestinal tract, as is the case for this roundworm. In contrast, lar- , val roundworms offish may be found in almost every organ, but they are common in the mesenteries, liver, and musculature. The life cycle of Biilbodacnitis always in- volves an invertebrate for the first intermedi- ate host and fish, via food chains, as the defini- tive host. Other nematodes use the fish as the second intermediate host and develop to adults in the intestinal tract of piscivorous fish, birds, and mammals (Hoffman 1967). Biilbodacnitis scotti was found in all of the cutthroat trout in this survey. It was one of the parasites described by Bangham (1951) in his studies of the parasites of fishes from Yellow- stone Lake. Salm.incola In the Crustacea there are two groups: the subclass Branchiura (fish lice) and the subclass Copepoda, some of which resemble free-liv- ing copepods. Certain species, such as the genera Ar^w/u.s, Lernaea, and Ergasilus, are very serious pests in fish culture, sometimes in nature, and have become increasingly im- portant in recent years (Hoffman 1967). Salmincola belongs to the order Lerneopo- didea, which has the following key character- istics: cephalothorax short, stout, inclined at angle to body axis; separated from trunk by groove, no distinct dorsal carapace. Trunk short and stout, often flattened dorsoven- trally, with no signs of segmentation. No ab- domen, caudal rami, or posterior processes. Small transparent genital process present in young females and often in adult organisms. Egg strings usuallv long and slender (Hoffman 1967). They are parasitic on freshwater fishes. The typical life cycle includes the following steps: April 1987 Heckmann, Ching: Trout Parasites 271 Fig. 7. Spores (s) of the fungus Ichthi/ophonus found in Salmo clarki (400X). copepod hatches into small, free-swimming larva which may exist two days; larva possess mouth parts which bear a peculiar filament for attachment to fish; larva forces filament into tissue of fish and attaches second maxillae to filament which becomes the bulla, thus at- taching itself permanently to fish. The entire animal undergoes degeneration, becoming a grublike parasite. The male is usually much smaller than female. Copulation occurs two and one-half to three weeks after attachment; male releases hold on gill and attaches to fe- male. After fertilization, male dies. Each fe- male gives rise to two batches of embryonated eggs, after which she dies. Entire life cycle takes about two and one-half months (Fasten 1912, Savage 1935, and Hoffman 1967). Piscicola Leeches were found on the gills and base of fins for 8% of the cutthroat trout checked dur- ing 1985 for parasites. The leeches parasitic to fish belong to the phylum Annelida. Charac- teristics include: mouth large, opening from behind into entire sucker cavity; fixed phar- ynx which is a crushing tube extending to somite Xlll. Specific characteristics for Pisci- cola are: margins of body with 11 pairs of small, pulsatile vesicles, difficult to see on preserved specimens; 14 annuli per segment; body not clearly divided into anterior and pos- terior regions; postceca completely united into one; testisacs 6 pairs (Hoffman 1967). IchthyopJwnus. Saprolegnia During the 1985 survey, two Sohno clarki had fungal infections near the dorsal fin with extensive mycelial masses penetrating the soft tissue. This appeared to be a species of Ichthyophonus (Fig. 7), based on current morphological characteristics . Fungi are plantlike structures lacking chlorophyll. The assimilative phase consists of a true plasmodium or a mycelium, or rarely of separate uninuclear, independent cells not amoeboid and at no time uniting as a plasmod- iumlike structure (Hoffman 1967). Ichthyophonus, according to some sources, belongs to the Phycomycetes. Others have avoided trying to place this parasite because it is not a typical member of any class of fungi, thus referring to it as a member of the 272 Great Basin Naturalist Vol. 47, No. 2 Fungi Imperfecti. Ichthyophonus hoferi and Ichthijosporid- ium sp. have been reported from North Amer- ican rainbow trout (Erickson 1965, Gustafson and Rucker 1956, Ross and Parisot 1958). Ichthyophonus in rainbow trout in North America was first reported by Rucker and Gustafson (1953) from three locaHties in west- ern Washington. Ross and Parisot (1958) found Ichthyophonus in hatcheries adjacent to the Snake River in south central Idaho. The organism is commonly found in the kidney, spleen, liver, heart, stomach, intes- tine, visceral serosa, peritoneal exudate, gills, and brain. In the latest severe epizootic of rainbow trout, the spores were very numer- ous in the brain as well as in the musculature. Central nervous system involvement appar- ently resulted in partial denervation of the skeletal musculature, which caused spinal curvature. Cases have been reported on the body surface. Most of the older spores are encapsulated in small host cysts or granulo- mas. The other possible taxonomic name for the fungi would be Saprolegnia. This is character- ized by: presence of mycelium, usually con- tinuous throughout in active assimilative phase (nonseptate). Species of the genus Saprolegnia are usually implicated in fungal diseases of fish and fish eggs. These fungi of fish are often considered primary or sec- ondary invaders following tissue trauma, but once they start growing on a fish, the lesions usually continue to enlarge and may cause death to the host. Ligula Ligula is a common plerocercoid found in the body cavity of many species of cyprinid and catastomid fish. For the last survey con- ducted on the parasites of the ichthyofauna of Yellowstone Lake, two of eight longnose suck- ers contained Ligula plerocercoids. One ple- rocercoid measured 420 mm long by 13.5 mm wide, a length greater than that of the host. The host exhibited organ compression and atrophy, especially gonadal tissue, due to the cestode. In other cases the diseased fish show retarded growth and swollen abdomens. Ligulosis is caused by the plerocercoid of the cestode Ligula, which lives in the intes- tine of aquatic birds, and its larvae in the visceral cavity of fish. Ligula has no proglot- Table 5. Parasites of the cutthroat trout, Salmo clarki, for North America.** Those observed for S. clarki from Yellowstone Lake, Wyoming, are marked with an aster- isk. This is primarily based on Hoffman's guide (1967) plus specific studies on Yellowstone Lake fishes. A superscript L indicates larval stage. Protozoa: Costia necatrix Ichthyophthirius mitltifilis Mijxidium sp. Octomitus sp. *Tricho(lina tnittae *Trichophrija clarki * Haemop,reg.arina sp. *Costia pijrifonnis *Myxosporidan sp. * Mijxosoma sp. Cestoda: (Tapeworms) Cyathoccphahis truncatus Cyathoccphalus sp. * 'DiphijUohothrium corcliceps * DiphijUohothrium sp. * Diphyllohothrium ditremum * Diphyllohothrium dcndriticum Euhothrium salvelini Protcoccphahis arcticus Proteocephalus laruci Proteocephalus primaverus Proteocephalus salmonidicola Proteocephalus sp. Acanthocephala; (Spiny-headed worms) Echinorhynchus lateralis *Neoechinorhynchus rutili Neoechim)rhynchus sp. Hirudinea: (Leeches) * lllim)hdella sp. *Piscicola salmositica Crustacea: (Copepods) Lepeophtheirus salmonis Lernaeopoda bicauliculata Salmincola edwardsii *Salmincola sp. Digenea: (Flukes) Allocreadium lobatum ^ Apophallus sp. Cdinostomum marginatum * C repidostom u m fa rion is Crepidostomum transmarinum Crcpidostomum sp. Deropeiia piin^eiis Thurb. AUinroa squurrosa (Nutt.) Torr. Onjzopsis ht/iticnoides (R. & S.) Bicker Phr(iictdattim (Stokes) Reveal & Brotherson Eriogontim dcflcxum Torr. in Ives Eriogontim injlatiim Torr. & Frem. Eriogontim microthecttm Nutt. Eriogontim tvethcrillii Eastw. POLYPODIACEAE Adianttim capilltis-veneris L. PORTULACEAE Portulaca oleracea L. Ranunculaceae Clematis ligtisticifolia Nutt. in T. & G. Delphinium scaposum Greene Rhamnageae Ceanothtis greggii Gray Rhamnus betulacfolia Greene ROSACEAE Amelanchier utahensis Koehne Cercocarpus intricattis Wats. Cercocarpus montanus Raf. Coleogtjne ramosissima Torr. Holodiscus dumosus (Nutt.) Heller Purshia mcxicana (D. Don.) Welsh var. stansbun/i (Torr.) Welsh Rosa ivoodsii Lindl. Salicaceae Poptdtis fremontii Wats. Santaeac:eae Comandra umbellata (L.) Nutt. Sgrophulahiageae Castilleja chromosa A. Nels. Castilleja linariifolia Benth. in DC. Castilleja scabrida I']ast\v. Cordyhiiithiis icrightii Gray in Emory Pediciilahs centranthera Gray Penstemon barbatus (Cav.) Roth Penstemon comarrhenus Gray Penstemon cyanocaulis Payson Penstemon eatonii Gray Penstemon lenttis Pennell Penstemon palmeri Gray Penstemon utahensis Eastw. Solanaceae Solantim triflorum Nutt. Tamarigageae Tamarix ramosissima Ledeb. References Cited Albee, B. a., L. M, Shl'ltz, andS Goodrigh Atlas of the vascular plants of Utah. In press. Arnovv, L . B Albee, and A. Wygicoff, 1980. Flora of the central Wasatch Front, Utah. University of Utah Press, Salt Lake City. 663 pp. Bowers. J E 1982. Local floras of the Southwest, 1920-1980; an annotated bibliographv. Great Basin Nat. 42: 105-112. Cronquist, A , A Holmgren, N H Holmgren, and J. L Ren'Eal. 1972. Intermountain flora. Vol. 1. Hafner Publishing Company, New York. 270 pp. Cronquist, A , A Holmgren, N H. Holmgren, J L Re- veal. AND P K Holmgren 1977. Intermountain flora. Vol. 6. Columbia University Press, New York. 584 pp. 1984. Intermountain flora. Vol. 4. The New York Botanical Garden Press, New York. 573 pp. Grimes. J. 1984. Notes on the flora of Leslie Gulch, Malheur County, Oregon. Madroiio 31: 80-85. Harris. J. G. 1983. A vascular flora of the San Rafael Swell, Utah. Great Basin Nat. 43(1): 79-87. Holmgren. A., and J. L Reveal. 1966. A checklist of the vascular plants of the Intermountain Region. U.S.F.S. Research Paper INT. -32. 160 pp. Holmgren, N H. 1972. Plant geography of the Inter- mountain Region, //i A. Cronquist et al., Inter- mountain flora. Vol. 6. Columbia University Press, New York. 584 pp. HuNTOON, P., G. Billingslee, Jr.. and P. Breed. 1982. Geologic map of the Canyonlands National Park and vicinity. Canyonlands Natural History Associ- ation, Moab, Utah. LOOPE, W. L. 1977. Relationships of vegetation to envi- ronment in Canyonlands National Park. Unpub- lished dissertation, Utah State University, Logan. 142 pp. Madsen, J H 1983. Paleontological survey. Tar Sands Triangle in J. W. Sigler and J. S. Tuhy, eds.. Resource surveys. Tar Sands Triangle, Wayne and Garfield counties, Utah. 506 pp. 298 Great Basin Naturalist Vol. 47, No. 2 McLaughlin. S. P. 1986. Flori,stic analysis of the south- western United States. Great Basin Nat. 46: 46-65. Meyer, S 1980. The ecology of gypsophily in the Mohave desert. L'npublished dissertation, Claremont Col- lege, California. 199 pp. MUELLER-DUMBOIS. D , ,\ND H Ellenberg 1974. Aims and methods of vegetation ecology. John Wiley, New York. 547 pp. Shaw, R. J., M. E. Barkworth, and G M Briggs 1983. Manual of the vascular plants of Cache and Rich counties, Utah. 3d printing. Department of Biol- ogy, Utah State University, Logan. 384 pp. Shultz. L M . J TuHY. E E. Neely, F Smith, and J Shultz. 1983. Threatened and endangered plant resources. In J. W. Sigler and J. S. Tuhy, eds.. Resource surveys. Tar Sands Triangle, Wayne and Garfield counties, Utah. 506 pp. Sk;ler, J W , and J S Tuhy, eds. 1982. Ecological sur- veys, Altex oil leases, southern Utah. W. F. Sigler &: Associates, Inc., Logan, Utah. 120 pp. Simpson, G G 1980. Why and how; some problems and methods in historical biologv. Pergamon Press, Oxford. TuHY.J S, and S.Jensen. 1983. Soils and vegetation. /n J. W. Sigler and J. S. Tuhy, eds., Resource surveys of the Tar Sands Triangle, Wayne and Garfield counties, LUah. 506 pp. Welsh, S L 1983. Checklist of the plants of Glen Canyon National Recreation Area. U.S. Department of Interior, Park Service. Unpublished manuscript. 1986. A Utah flora. Great Basin Nat. Mem. 10. 894 pp. Welsh, S. L , N. D. Atwood, S Goodrich, E Neese, K. H Thorne, and B Albee. 1981. Preliminary in- dex of Utah vascular plant names. Great Basin Nat. 41(1); 1-108, EVALUATION OF THE IMPROVEMENT IN SENSITIVITY OF NESTED FREQUENCY PLOTS TO VEGETATIONAL CHANGE BY SUMMATION' Stuart D. Smith" ', Stephen C. Bunting", and M. Hironaka" Abstract. — At four sites in Idaho, frequency was measured separately with three different-sized plots (10 x 25, 15 x 33.5, and 20 x 50 cm) arranged in a nested configuration. These individual frequency values were added together to create a summed "frequency. This summed value was compared to the original frequency values generated by each individual plot size in respect to its ahilit)' to detect range trend. The sunniiation procedure consistently detected smaller changes in frequency than any indi\idual plot size. In addition, the summed values detected a significant change in more species at each site. Summing the frequency values usually detected changes at a lower alpha level than did any single plot (0. 10 vs. 0.20). Range trend has historically been defined as either apparent or measured. Apparent trend is a subjective rating reached with only one observation of the land. Various site and vegetational indicators of trend are observed and judged against published standards. This approach has been described by many au- thors, including Pickford and Reid (1942), Costello and Turner (1944), and Ellison and Croft (1944). Measured trend is an objective record of successive condition ratings. Two or more successive observations of condition must be made over an interval of time to determine measured trend. Before sampling for measured trend be- gins, the vegetational attribute with which condition (and thus measured trend) is mea- sured must be determined. Cover, produc- tion, density, and frequency are the most common attributes considered. For manage- ment purposes, the selected attribute should exhibit the following characteristics: (1) preci- sion, (2) ease in sampling, and (3) sensitivity to successional change. Fluctuations in any of the attributes due to between-year and be- tween-season weather variations and current grazing use reduce the precision and sensitiv- ity of the resulting measurements. Cover (both foliar and basal) and yield reflect these variations and, therefore, are too transient for determining trend. Density is the attribute least affected by weather variation, especially with perennial vegetation. However, as Strickler and Stearns (1963) point out, mea- suring density can become tedious or impre- cise if the plants are small and numerous or if they reproduce vegetatively. Considering the alternatives, frequency becomes a logical choice. A search of the available literature shows various authors, including Blackman (1942), Hyder et al. (1963), and Greig-Smith (1964) alluding to the advantages of frequency for determining vegetational change. As a function of density, frequency is relatively sta- ble over time. This stability, coupled with objective measurements, provides a high de- gree of precision. Brown (1954) adds that fre- quency is measured easily and rapidly. In ad- dition, use of frequency as a method of monitoring range trend is becoming more prevalent (U.S. Department of Agriculture, Forest Service 1981, Despain 1982). Results presented by Smith et al. (1986) show fre- quency to be a sensitive measure of succes- sional change. Frequency, however, does have certain limitations that must be accounted for to maxi- mize its usefulness. These limitations have been listed by Kershaw (1973) as four vari- ables that determine frequency results: (1) plot size, (2) plant size, (3) plant distribution, and (4) plant density. A change in any one of these variables will change the resulting fre- quency value (Brown 1954), thus obscuring determination of the variable(s) responsible for change. It is impossible to control plant Kt-iearcli was supported by .Vlclntire-Stennis tunds and the Forest. Wildlife and Range Experiment Station, University of Idaho, Moscow. Idaho Contribution No. 271. "Department of Range Resources, University of Idaho, Moscow, Idaho 83843 Present address: AppHcations Branch, EROS Data Center, Sioux Falls, South Dakota 57198. 299 300 Great Basin Naturalist Vol. 47, No. 2 size, distribution, or density when sampling vegetation. Plot size, therefore, is the only variable that can be altered to give desired frequency values. Appropriate fiequency val- ues for vegetation monitoring are usually con- sidered to be in the 63 to 86% range for the most prevalent species. At these levels, plot sizes will be one and two times, respectively, the mean area of the individuals of that species in a randomly distributed population (Curtis and Mcintosh 1950). The ideal frequency sampling scheme to account for variations in plant size, distribu- tion, and density would include a different- sized plot for each species (Despain 1982), since a given plot size will sample certain species more adequately than others (Hyder et al. 1963). Many investigators have avoided this complexity by standardizing the plot size used on a variety of vegetation types (Shimwell 1971, Tueller et al. 1972). How- ever, the inherent variability in plant size, distribution, and density often makes it diffi- cult for only one plot size to adequately sam- ple various areas. The use of a single plot size is further con- strained by Raunkiaer s Law of Frequency (Raunkiaer 1934), which states that there are more species with few individuals than with many (Shimwell 1971). This skewed distribu- tion of frequencies can present problems in frequency sampling for range trend, since it is more difficult to detect change over time in species with low frequencies (Smith et al. 1986). Although most "key" management spe- cies monitored for range trend are not rare, there are often cases when interest is directed toward both numerous and scarce species oc- cupying the same site. Increasing species fre- quency by enlarging a single plot size could improve the likelihood of detecting range trend in species having lower frequencies. However, this is not practical, since enlarging plot size would simultaneously increase fre- quency for all species present. If the fre- quency of any species reached 100%, it would become impossible to make comparisons be- cause future increases in density of that spe- cies would still yield values of 100% fre- quency. Therefore, enlarging plot size could potentially narrow the range of frequency val- ues of various species and thus reduce the total number of species having frequency val- ues useful for determining range trend. A preferable alternative would somehow widen the range of frequencies and at the same time improve the sensitivity to change for those species with lower frequency readings. One alternative solution might be to select one plot size, among several, best suited for a particular site. This is employed in the nested frequency plot method where three or four variously sized plots are located (nested) within each other in a single configuration. Frequencies recorded for each of the plot sizes are compared. Data from only the plot size giving the most sensitive detection of change over a period of time are used to deter- mine range trend for a site. Although use of frequency plots has the potential to improve sensitivity for detection of trend, procedures commonly employed with the nested tech- nique may not use data as efficiently, since data from only one of the several plot sizes are ever utilized for any given species. This study investigated the summation of frequencies from three different nested plot sizes in an effort to increase sensitivity and efficiency for detection of trend of any individ- ual plot size alone. For example, in 100 nested configurations each consisting of three plot sizes, a total occurrence of 300 would be possi- ble for any given species. It is proposed that such a summation would have three advan- tages: (1) Compared to any single plot size, it would widen the range of possible occurrence values for any species by increasing the maxi- mum possible number of observations from 100 to 300 (assuming three nested plots are used). Differences that might not be signifi- cant at lower frequency levels may become significant when the range of occurrences is increased. (2) The smaller plot sizes in the nested design would provide inherently smaller frequency readings. Should such smaller values be added to the total, they would decrease the probability that the summed value would reach 300. This would improve the likelihood of detecting changes in already abimdant species whose frequency in- creased over time. (3) It should increase the number of species showing significant changes in frequency over time, adding credi- bility to the estimation of range trend. April 1987 Smith et al.: Vegetational Atfribute Measurement 301 Methods Field Methods During the summer of 1981, four sites lo- cated within 70 km of Salmon, Idaho, were studied. These sites were selected to test the procedures in a variety of vegetational types. Listed as habitat types (Hironaka et al. 1983, Steele et al. 1981), the sites are: 1. Pinus ponderoso/Festuca idaJiocnsis. Located at an elevation of 1,500 m, this site exhibited a typical fire-maintained P. ponderosa stand structure (Morris and Mowat 1958). It combined an uneven- aged stand overstory with a grass- dominated understory. 2. Ai-femisia tridcntata subsp. vaseyanal Festuca idahocnsis. Several Pscudotsufia menzicsii trees had invaded this site, al- though there was no indication of previ- ous occupation by this species. The ele- vation was 1,975 m. 3. Artemisia tridcntata subsp. vaseyanal Festuca idaJiocnsis. This site had been burned three years prior to sampling. The elevation was 2,250 m. 4. Artemisia tridcntata subsp. vaseyanal Festuca idaJioensis. This site was located on an exposed, high-elevation (2,725 m) ridge. There was an abundance of small forbs and a lack of shrubs. The few Artemisia individuals present were small and stunted. Vegetation data reported in this study con- sist of the herbaceous component only. Usage of scientific names in this report except for Ariemisia follows that of Hitchcock and Cron- quist(1973). The sampling process consisted of three phases designed to simulate trend sampling over a period of years. In phase 1, frequency and cover baseline measurements were taken. Phase 2 consisted of randomly exclud- ing known amounts of vegetation from further sampling, simulating a known compositional change over time. In phase 3, the plots sam- pled in phase 1 were resampled after the veg- etation change had been created. Phases 2 and 3 were completed a total of three times, since three different levels of change were studied. The frequency sampling unit consisted of a series of metal plot frames arranged concen- trically in a nested configuration. Plot sizes were 10 x 25, 15 x 33.5, and 20 x 50 cm, representing areas of 250, 500, and 1,000 cm", respectively. The nested configuration al- lowed direct comparison of any different size, since a plant located in a particular plot would also be included in all larger plots. At each site, ten 10-m transects were lo- cated within a uniform area. The transects were usually placed parallel to each other with a distance of 2 to 3 m between them. Along each transect, 40 of the nested configurations were uniformly spaced, for a total of 400 sam- ples per site. At each of the 400 nested configurations, frequency of occurrence for indixidual species rooted within each of the three frequency plots was recorded. These separate frequen- cies were also summed into one value for each species. In addition, 120 systematically lo- cated point measurements were made along each transect (1,200 points per site) to mea- sure foliar cover. These frequency and cover measurements comprise phase 1. In phase 2, changes in density were created to simulate successional trend. To do this, randomly lo- cated sections of the transect, each 20 cm long, were established. Each section also ex- tended perpendicularly from the transect to include all sizes of the sample plots. Any plant located within these "exclusion areas ' was considered to have disappeared, thus simulat- ing vegetation change over time. To achieve the desired levels of change (10, 20, and 30% reduction in vegetation), 5, 10, and 15 exclu- sion areas were located on each transect, ap- proximating a 10, 20, and 30% reduction in ground surface area occupied by the exclusion areas. Var\ing amounts of change within a single sample plot were created by superim- posing the randomly located exclusion areas over the uniformly spaced sample plots. It was possible for an exclusion area to fall directly on a sample plot removing all vegetation from that plot. An exclusion area could also fall between two sample plots and not affect ei- ther. However, neither of these possibilities occurred frec}uently. Instead, varying amounts of partial overlap occurred between the exclusion areas and the sample plots. Fol- lowing each of the three levels of change, phase 3 resampled the original sample plots, minus the exclusion areas, for frequency and cover. 302 Great Basin Naturalist Vol. 47, No. 2 While this study considered "change" to be a reduction in species density, a reversal of the data could be used to illustrate the effects of species increases. With the same set of data, however, analysis of either a reduction or increase would still be possible. Since this study was testing for sensitivity to small levels of change, the amount of change induced was limited to a maximum of 30%. The objective of this study was to compare changes in frequency levels detected by dif- ferent plot sizes. Without a reference stan- dard, it would be impossible to determine if the frequency changes detected by one plot size were more precise than any other plot size. Frequency itself could not be used as a reference for two reasons: (1) it is the value being tested, and (2) its results are highly related to plot size. For this reason, a vegeta- tion measurement other than frequency had to be established as a reference. Density, yield, and cover were considered. For practi- cal reasons, cover was the attribute chosen. It was found, however, that basal cover levels at the sites studied were too small to be useful. Foliar cover was thus chosen as the reference standard. It was determined that using the previously mentioned 1,200 points per site would give an accurate assessment of change. The sole purpose of the foliar cover data was to determine if a significant change had occurred as a result of the exclusion process. Normally, foliar cover is not used to determine trend; it is subject to yearly and seasonal fluctuations. However, it was used as a parameter in this study, since all sampling on a site was done within a few days time. Data Analysis Sampling 400 plots is usually considered too time-consuming for most management requirements. Therefore, to test the proce- dure under likely operating conditions, the original 400 nested configurations were con- sidered to be a population, from which a ran- dom sample of 200 was drawn for analysis. The 600 foliar cover points associated with these 200 samples were also used in the analysis. All results shown here are from the smaller (200 plot) sample size. Data from each of the four sites were analyzed independently; no at- tempt was made to combine information from different sites. Table 1. Percent foliar cover before and after each exclusion level. Exclusion Site level (%) 1 2 3 4 0 20 54 45 38 10 17 50 42 34 20 15**' 44** ,37** 31* 30 13** ,39** .32** 28** ' • significant at a 0.20 ** significant at a 0.10 Signilicancf determined by separate t-tests between the 0% removal level and each ol the "exclusion" levels within a column. Site 1 Pinus punderosalFestuca idahoensis habitat type. Site 2 Artemisia tridentata subsp. vaseyanalFestuca idahoensis habitat type (unburned). Site .3 Artemisia tridentata subsp. vaseyanalFestuca idahoensis habitat type (burned). Site 4 Artemisia tridentata subsp. vaseyanalFestuca idahoensis habitat type (high-elevation ridgetop). Foliar Cover Considering foliar cover as a continuous variable, individual t-tests were used to com- pare differences between control (original) conditions and each of the three "exclusion" treatments. For these tests, each of the 10 transects within a site was considered one sample. Results were compared at alpha lev- els of 0.10 and 0.20. Frequency The observations per species from the three individual plot sizes were added together to create a summed frequency value for each nested configuration. The frequency data thus contained the number of occurrences of each species per plot size (including the summed value) at the control and each "exclusion" level. For the frecjuency analysis, each spe- cies-plot-size combination was considered a sample. Using frequency as a discrete, present-or-absent variable, a chi-square test with Yates' correction factor (Mueller- Dombois and Ellenberg 1974) was used to determine for each plot size (including the summed value) whether significant (a = 0.20 or 0.10) changes in frequency had occurred between the control and any of the exclusion levels. This procedure allowed for comparison of the summation results with those for each individual plot size. Results and Discussion Foliar Cover Results of the individual t-tests, using the foliar cover data, showed that it was not possi- April 1987 Smith etal: Vpx.pztational Attribute Measurement 303 Table 2. Results on selected species ironi the (>lii-s(jiiare anahsis on fre(iiiene\ for the I'inu.s pondcrosu/Fcstuca idaliocnsis habitat type. The first row for each plot size contains the initial ire((iiency and the three subsequent frecjuencies resulting from the exclusion process. The second row is the percent change from the original frequency. This list includes only those species in which a change was detected. Siunnied \alues listed here were standardized to a 0-100 range after analysis. Species Festuca idahoensis Antcttnaria microphylhi Lupinus caudatiis Aiiropyron spicatum Poa saiidberiiii Apocynum androsacmij oUum Frasero aJhicaulis Initial Plot type E^xcmsi on level [Vc) cover (%) 0 10 20 30 (cm-) 7.7 250 26 24 22 20 8 15 23* 500 45 42 39 36 7 13 20** lOOO 62 57 53 48 8 15* 23** Sum 44 41 38 34 7 14** 23** 2.3 250 24 22 20 18 8 17 25* 500 36 34 30 28 6 17 22* 1000 52 50 45 42 4 13 19** Sum 37 36 32 29 3 14** 22** 1.0 250 5 4 4 4 20 20 20 500 10 10 8 8 0 20 20 1000 18 14 12 10 22 33* 44** Sum 11 10 8 ■" 9 27** 36** 0.3 250 4 4 3 3 0 25 25 500 8 8 7 6 0 12 25 1000 15 12 10 8 20 33 47** Sum 9 8 7 6 11 22* 33** 0.2 250 10 9 ( 6 10 30 40 500 14 14 12 10 0 14 29 1000 20 19 17 14 5 15 30* Sum 15 14 12 10 7 20 30** 1.7 250 8 8 8 6 0 0 25 500 14 12 11 10 14 21 29 1000 20 18 16 15 10 20 25 Sum 14 12 11 10 14 21 ■7g** 1.0 250 6 6 6 4 0 0 33 500 8 8 8 6 0 0 25 1000 IS 16 16 14 304 Table 2 continued. Great Basin Naturalist Vol. 47, No. 2 Species Initial Plot type cxciusi on levei {"/c) cover (%) 0 10 20 30 (cni^) 11 11 22 Sum 10 10 10 8 0 0 20* 0.7 250 7 6 6 6 14 14 14 500 14 13 12 12 7 14 14 1000 20 18 17 16 10 15 20 Sum 14 13 12 11 7 14 21* 0 250 6 4 4 2 33 33 67 500 12 10 10 8 17 17 33 1000 15 14 14 12 7 7 20 Sum 11 20 9 8 9 18 27* 0 250 3 2 2 1 33 33 67 500 6 5 4 2 17 33 67 1000 8 8 6 6 0 25 25 Sum 6 5 4 3 17 33 50** 0 250 2 2 1 1 0 50 50 500 2 2 2 1 0 0 50 1000 6 6 4 3 0 33 50 Sum 3 3 2 2 0 33 33** Arenaria congesta Collinsia parviflora Stipa occidentalis Tragopogon dubiiis Significant at a 0.20. Significant at a 0.10. ble to detect a significant difference (a = 0. 20) in foliar cover when only 10% of the ground surface area was excluded (Table 1). How- ever, at the 20% "exclusion level," all sites showed significant (a — 0. 10 for sites 1, 2, and 3; a = 0.20 for site 4) reductions in foliar cover. When 30% of the ground surface area was excluded, all four sites showed significant (a = 0. 10) reductions in foliar cover when compared to their respective controls. These data provide additional information indicating that a change had occurred. Once it was known that a statistical change in cover had occurred, frequency data were analyzed. Frequency Except as noted, space considerations allow the frequency results from only the Pinus pon- derosa/Festuca idahoensis habitat type to be reported. The results from the three other sites were similar. Results from the chi-square analysis on fre- quency data are shown in Tables 2 and 3. Since the summation procedure used data from three plot sizes, a total summed "fre- quency" of 300% was possible. The chi-square analysis tested for significant changes in spe- cies occurrence over a potential range from 0 April 1987 Smith etal: Vecetational Attribute Measurement 305 Table 3. Total number of herbaceous species which are significantly different (a 0.20) from the initial sample period at three exclusion levels for the 20 x 50 cm and summation plots. Habitat type Pinus punderosa/Festuca idahocnsis Artemisia tridentata subsp. vaseyana/Festtica idahoensis (unburned) A7-temisi(i tridentata subsp. vaseijana/Festuca idahoensis (burned) Artemisia tridentata subsp. vaseyana/Festuca idahoensis (high elevation) Plot Exclusion level (%) type 10 20 30 (cm^) 1000 0 2 5 Sum 0 4 11 1000 0 3 5 Sum 2 5 8 1000 0 2 5 Sum 0 4 10 1000 0 2 5 Sum 2 6 8 to 300 for the summed data, and 0 to 100 for the individual plot sizes. For ease of interpre- tation, the summed values were standard- ized, after analysis, to a maximum of 100%, consistent with the individual plot levels. It should be recognized that data gathered with nested plots are not truly independent; a species recorded in a smaller plot is also in all larger plots. Theoretically, this may introduce a degree of bias. Under actual testing, how- ever, this bias may not be significant. Hiro- naka (1985) demonstrated that separate, ran- domly placed frequency plot data were highly correlated (R" = .998) with nested plot fre- quency data. This suggests that the bias due to nested quadrats may be small and outweighed by the advantage of increased sensitivity. Table 2 shows the results for the summation technique for the Pinus ponderosa/Festuca idahoensis habitat type. The table shows, by species, the relationship between initial fre- quency and the smallest subsequent change in frequency that is statistically different from the control. These changes were created by the three (10, 20, and 30%) exclusion levels. The summation technique detected a smaller change in frequency than any individual plot size at any given initial frequency. The sum- mation technique was also able to detect changes in frequency in six additional species when 30% of the ground surface area was excluded. The additional species frequently had coverage values less than 2%, a value so small that changes were not detected with any single plot size. The summation technique proved useful in increasing the resolution of range trend fre- quency data in several additional ways. The technique often detected a change with greater confidence at a lower alpha level (0. 10 versus 0. 20) than any single plot size (Table 2). For example, with Festuca idahoensis in Table 2, both summation and single-plot methods detected a 15% change in frequency. Furthermore, the summation technique de- tected this change at a probability level of 0.10, whereas the single-plot difference was significant at the a = 0.20 level only. The summation technique detected change at a lower initial frequency than any single plot size (Table 2). Using the summation process would be advantageous when attempting to detect change in species having lower fre- quency values. Compared to any individual plot size, the summation procedure detected significant changes in an average of four addi- tional species per site (Table 3). Detecting change in a greater number of species at smaller amounts of change adds credibility and confidence to any judgment about range trend. The use of summed frequencies can be an advantage also when the change is relatively large. For example, if a particular species of interest was becoming more numerous over time, the smaller plots included in the nested plot configuration would help prevent the re- sulting "frequency" value from truncating at 100 in subsequent measures. Even though one or more of the larger plots in the configu- ration might reach 100% frequency as the spe- cies became more numerous, it would be un- likely for one of the smaller plots to do so at the same time. When the frequencies of all the plot sizes are added together, the presence of the smaller plot's frequency will prevent the summed total from reaching 300% "fre- quency" (assuming three plot sizes are used). 306 Great Basin Naturalist Vol. 47, No. 2 If, instead, a single plot had been used to monitor the same species, it would be initially advantageous to use a plot size giving an initial frequency of 20 to 80%. However, if the spe- cies increased in density and the fretjuency at any succeeding sample reached 100%, subse- quent increases in that species could not be detected. Since the influence of the smaller plot sizes on the summed total is inherent, the summation technique would eliminate the need to change plot size over time as a species experienced major changes in density. There- fore, using the sums of nested plots provides more sensitivity to vegetational change over a wider range of species abundance than any single plot. Smith et al. (1986) noted that initial fre- quency and magnitude of ensuing changes are the main factors controlling the sensitivity of frequency plots to vegetational change. This also held true when the change being sampled used the sums of nested plots. As initial fre- (}uency and/or percentage change increased, so did the ability of the nested frequency plots to detect that change. Detection of small per- centage changes required a large initial fre- quency. It was rare to detect a 10% change if the initial frequency was less than 60%, but a 30% change was often detected when the ini- tial frequency was less than 15%. Conclusion Frequency data are highly correlated with plot size. Although freciuency data gathered with a single plot size are easiest to analyze, no one plot size can adequately sample a wide variety of plant species at the same time. This study examined the possibility of summing data from three different plot sizes, arranged in a nested configuration, in an effort to fur- ther improve the sensitivity and efficiency of frequency as a method for detection of trend. For the four sites studied, summation of frequencies provided greatest sensitivity to vegetational change. Such changes in summa- tion values were shown to be significant at lower alpha levels than for any single plot within the nested configuration. These results were consistent over a wide range of frequen- cies. In addition, summation was superior for detecting changes in species having low initial frequencies and foliar coverages. Finally, the summation techniciue detected significant changes in more species than did any single plot size. Literature Cited Blackman. G E 1942. Statistical and ecological studies in the distribution of species in plant communi- ties. Annals of Botany, N.S. 6: .351-370. Brown, D 19.54. Methods of surveying and measuring vegetation. Commonwealth Byreau of Pastures and Field Crops, Hurley, Berkeshire. Bulletin 42. 233 pp. CosTELLO. D F, andG Turner 1944. Judging condition and utilization of short-grass ranges on the central Great Plains. USDA Farmers Bull. 1949. 21 pp. Curtis. J T , and R P McIntosh 19.50. The interrela- tions of certain analytic and synthetic phytosocio- logical characters. Ecology 31: 4.34-455. Despain. D. W 1982. Myths of frequency sampling. Pa- per presented at the winter meeting of the Arizona Section of the Society for Range Management, Tucson, Arizona. 17 pp. Ellison.L .. andA R. Croft 1944. Principles and indica- tors forjudging condition and trend of high range watersheds. USDA Forest Service, Intmn. Forest and Range E.xpt. Sta. Res. Pap. 6. 65 pp. Grek:-Smith, P 1964. Quantitative plant ecology. But- teiAvorths, London. 256 pp. HiRONAKA, M 1985. Frecjuency approaches to monitor rangeland vegetation. Proceedings, 38th annual meeting. Society for Range Management, Salt Lake City, Utah. HiRONAKA. M., M. FOSRERG. AND A WiNWARD 1983. Shruh habitats of southern Idaho. University of Idaho For. Wildlife and Range E.xpt: Sta. Bull. 35. 44 pp. Hitchcock, C. L., and A. Cronoi-'ist. 1973. Flora of the Pacific Northwest. University of Washington Press, Seattle. 7.30 pp. Hyder. D. N., C. E. Conrad. P T Tueller, L D. Calvin, C E Poulton, and F W Sneva 1963. Frecjuency sampling in sagebrush-bunchgrass vegetation. Ecology 44: 740-746. Kershaw, K. A. 1973. Quantitative and dynamic plant ecology. 2ded. American Elsevier, New York. .308 pp. Morris, W G . and E L Mow.\t 19.58. Some effects of thinning a ponderosa pine thicket witii a pre- scribed fire. J. Forest. .56: 203-209. Mueli.er-Dombois, D., and H Ellenberc. 1974. Aims and methods of vegetation ecology. John Wiley and Sons, New York. .547 pp. PiCKFORD. G D . AND E H Reid 1942. Basis forjudging subalpine grassland ranges of Oregon and Wash- ington. USDA Circ. 6.55. 37 pp. Raunkiaer. C 1934. The life forms of plants and statistical plant geography; being the collected papers of C. Raunkiaer, translated into English by H. Gilbert- Carter, A. Fausboll and A. G. Tansley. Claren- don, Oxford. 632 pp. SlllMWELL. D W 1971. The description and classification of vegetation. University of Washington Press, Seattle. .322 pp. April 1987 Smith etal: Vecetational Atfribute Measurement 307 Smith, S. D , S. C Bunting, and M. Hihdnaka 1986. ods, a .symposium. USDA F"oiest Service Misc. Sensitivity of frequency plots for detecting vegeta- Publ. No. 940. 172 pp. tion change. Northwest Sci. 60: 279-286. Tl eller, F T , C Lohain, K Kippinc, and C Wilkie. Steele. R,. R D Pfister, R. A Rvker. and J A Kitiams 1972. Methods for measuring vegetation changes 1981. Forest habitat types of central Idaho. USDA on Nevada rangelands. Nevada Agric. Expt. Sta. Forest Service, Intmn. Forest and Range E.xpt. Tech. Bull. 16. 55 pp. Sta. Tech. Rep. INT-114. 138 pp. US Department ok AcRict ltlre. Forest Service. Strickler. G S, AND F\V Stearns 1963. The determi- 1981. Region 4 range analysis handbook (draft). nation of plant density. In Range research nieth- 125 pp. NOTES ON MYCOPHAGY IN FOUR SPECIES OF MICE IN THE GENUS PEROMYSCUS Chris Maser and Zane Maser' Abstract — Fungal spores in the stomach contents and/or feces of 696 Peromijscus spp. showed that about half had eaten fungi: of 486 deer mice (P. numiculattis), 48%; of 160 white-footed mice {P. leiicopiis), 59%; of 40 canyon mice (P. crinitus), 12%; and of lOpifion mice (P. truei), 90%. Although much has been written about the genus Peromyscus, especially P- manicidatus and P. leucopiis, relatively little has been written about their food habits. King's (1968) book on the genus Peromyscus does not con- sider food habits. Deer mice (P. maniculatiis) have long been considered a problem in refor- estation in the Pacific Northwest (Gashwiler 1965, 1979, Hooven 1958, Sullivan 1979a, b). Most studies on food habits lack information on fungi (e.g.. Cook et al. 1982, Douglac 1969, Flake 1973, Halford 1981, Lackey et al. 1985, Osborne and Sheppe 1971). Some studies in- clude fungi as one of many kinds of foods eaten (e.g., Martelland Macaulay 1981, Merrittand Merritt 1980, Schloyer 1976, Whitaker 1966, Williams 1959). A few studies deal specifically with fungi in the diet of Peromyscus (e.g., Harling and McClaren 1970, Hunt and Maser 1985, Maser et al. 1978). In this study we examine hypogeous, my- corrhizal fungi in the diet of four members of the genus Peromyscus. Our intent was a sur- vey of fungal use by particular members of the genus Peromyscus to ascertain their potential functional dynamics within the habitat. Al- though it has taken more than 10 years to gather enough material, our study has some deficiencies because some animals were col- lected in fungal fruiting seasons whereas oth- ers were not. Also, little study has been done with mycophagy in grassland and shrub- steppe habitats; in fact, little is known about hypogeous fungi in such environments (Trappe 1981). The data we present are new, and they should help us understand the func- tional role of wide-ranging, highly adaptable small mammals in their respective habitats. Methods and Materials The 696 mice used in our study were snap- trapped over widely scattered areas in North America. Most specimens were quick-frozen in the field for later analysis. Of the mice, 324 (collected by us) were analyzed for fungi by stomach content, and 372 (collected by others for us) were analyzed by fecal content. Both stomach contents and feces were preserved in vials of 10% formalin. Stomach contents and feces were micro- scopically examined at 100, 400, and 1,000X magnification. A small amount of equally mixed material was randomly sampled from each vial with narrow, parallel-sided forceps, placed on a microscope slide, mixed with a drop of Melzer s reagent (I, KI, and chloral hydrate), and enclosed under a 22 x 40 mm cover slip. The slide was systematically exam- ined for fungal spores. Fungal taxa were iden- tified with the aid of a spore key (Trappe et al. , in prep.). We use percent frequency because percent volume cannot be used for fecal analysis. Results and Discussion Twenty-seven fungal taxa were identified from the 696 mice examined: P. maniculatus contained 22 taxa (Table 1), P. leucopus 18 taxa (Table 2), P. truei 11 taxa (Table 2), P. crinitus 1 taxon (Table 2). The Mice Peromijscus maniculatus (deer mouse). There were 209 P. maniculatus examined 'us. Department of the Interior, Bureau of Land Manasement, Forestry Sciences Laboratory, 32(K) Jefferson Way, Corvallis, Oregon 973^3L Department of Forest Science, Oregon State University, Corvallis, Oregon 97331. 308 April 1987 Maser, Maser: Micophagyin Mice 309 Table 1. Percent frequency of fungal taxa from 486 Peromyscus maniculattis. Western Washington and southwest Western British Northeast Southeast Ontario, Oregon Cokmibia Oregon Oregon Iowa Canada Fungal genera (n = 209) (n = 92) (n = 27) (n = 128) (n = 19) (n=ll) ASCOMYCETES Hypogeous Balsamia 2 Cenococctnn 1 2 Choiromyces 1 Elaphomyces 2 Genabea 1 Genea 5 Geopora 1 Hydnotnja 2 Picoa 3 Tuber 2 33 5 Basidiomycetes Hypogeous Gautieria 4 Octavianina 2 Hymenogaster 7 1 5 Hysterangium 2 Leucogaster 3 Leucophleps 1 Martellia group 1 Melanogaster 2 Rhizopogon 25 1 19 5 Zygomycetes Hypogeous Endogone 3 7 Glomus 21 35 8 17 32 100 Sclerocystis 1 5 Other fungi Unidentified 6 7 4 14 11 Lichen Unidentified 1 from western Oregon forests (Table 1), and 22 fungal taxa were found. The mice were from Douglas-fir {Pseudotstiga menziesii) forests where they are known to be mycophagists (Hunt and Maser 1985). Although a wide vari- ety of fungi was eaten, Rhizopogon and Glomus had a disproportionately high percent frequency of consumption (25 and 21, respectively). Peromyscus maniculattis from western Washington and southwestern British Colum- bia ate seven fungal taxa (Table 1). Most of these mice were in riparian habitats. Three fungal taxa in the family Endogonaceae had 47% frequency, whereas others had 7% fre- quency and a small number (4) of other fungal taxa. The three genera Endogone , Glomus, and Sclerocystis (family Endogonaceae) also represented the three highest percent fre- quencies (7, 35, and 5, respectively). Peromyscus maniculatus in northeastern Oregon had eaten fungi of three taxa (Table 1). Tuber sp., with 33% frequency, was gleaned from the bluebunch wheatgrass (Agropyron spicatum)-ldAho fescue {Festuca idahoensis) habitat; the next highest percent frequency (19) was Rhizopogon from mice caught in the lodgepole pine {Pinus contorta) habitat. Little fungus was found in the stomachs of 128 Peromyscus maniculatus from the arid sagebrush {Artemisia spp.) steppe of south- eastern Oregon (Table 1). The only identifi- able taxon was Glomus at 17% frequency. 310 Great Basin Naturalist Vol. 47, No. 2 Table 2. Percent frequency of fungal taxu froi Peromijscus spp. 210 P. leucopus P. truei P. crinitiis Fungal genera (n=160) (n=10) (n = 40) Ascomycetes Hypogeous Balsamia 1 10 Barssia 1 Choiromyces 4 Elaphomyces 3 10 Genea 3 20 Geopora 6 10 Hydnohohtes 1 Picoa 3 Tuber 5 10 Basidiomycetes Hypogeous Gauticria I 10 Octavianina I 20 Hymetio^dster 13 10 Leucop.aster 1 20 Mchinofiaster 1 Rhizopofion 20 70 Zyc;()mycetes Hypogeous Endoaone 3 Glomtts 25 10 3 Sclcrocystls 1 Other Fungi Unidentified 14 20 11 Peromijscus maniculatiis from Iowa and Manitouwadge, Ontario, Canada, also con- centrated on fungi of the genus Glomus, with a 32 and 100% frequency, respectively (Table 1). The stomachs of the P. maniculatus from Manitouwadge contained Glomus in the fol- lowing amounts: 10 mice, 100%, and 1 mouse, 95% by volume. These mice were trapped in a black spruce {Picea mariana) forest. Peromyscus leucopus (white-iooted mouse). — All 160 P. leucopus examined from Iowa were trapped in wooded habitats (Table 2). The mice had eaten fungi of eight taxa, percent frequency 1; and three taxa, percent frequency greater than 10. The family Endog- onaceae (Endogone, Glomus, and Sclerocys- tis) had 28% frequency, and Rliizopogon, an obligatory symbiont with Pinaceae, had 20% frequency. Peromyscus truei (piiion mouse). — Ten P. truei from southwestern Oregon had con- sumed fungi of 11 taxa, ranging from 10 to 70% frequency (Table 2). These mice were trapped in mixed conifer-hardwood forest, a habitat different from the rangeland habitat that P. truei is associated with throughout most of its geographical distribution. Peromyscus crinitus (canyon mouse). — Forty P. crinitus were collected in the arid sagebrush canyonlands of southeastern Ore- gon. Because little is known about the fungi of the sagebrush steppe of southeastern Oregon, only one genus, Glomus, could be identified with certainty (Table 2). The Fungi Mycorrhizal fungi absorb nutrients and wa- ter from soil and translocate them to a host plant. The host provides sugars from photo- synthesis to the mycorrhizal fungi. Fungal hy- phae extend into the soil and serve as exten- sions of the host root systems and are both physiologically and geometrically more effec- tive for nutrient absorption than the roots themselves (Maser et al. 1978, Trappe 1981, Trappe and Fogel 1977, Trappe and Maser 1977). Both ectomycorrhizal and endomycor- rhizal fungi serve similar purposes, but they usually occur on different host plants. When ectomycorrhizal fungi are predomi- nant in the fungal diet of small mammals, they are also predominant in the habitat, such as coniferous forests. There they are mostly As- comycetes and Basidiomycetes associated with Pinaceae, Fagaceae, Salicaceae, Betu- laceae, and a few other plant families (Fogel and Trappe 1978, Maser et al. 1978, Trappe and Maser 1977). The Endogonaceae (Zygomycetes) include saprophytic, ectomycorrhizal, and vesicular- arbuscular (VA) endomycorrhizal species. Vesicular-arbuscular mycorrhizae are formed by Endogonaceae with most higher plants that are not ectomycorrhizal, including the Cupressaceae, Taxodiaceae, Aceraceae, and most herbaceous plants. Most plants on streambanks, meadows, prairies, in early stages of forest succession, forest understo- ries, or forests containing VA-mycorrhizal tree species have VA-mycorrhizal Endogo- naceae associated with their roots (Maser et al. 1978, Miller 1979, Reece and Bonham 1978, Trappe 1981, Williams and Aldon 1976). Sampling in such habitats showed that the fungi of highest frequency were VA-my- corrhizal taxa. Interactions Tables 1 and 2 show that Endogonaceae April 1987 MaSEK, MaSEK: MlCOPHACV IN MiCE 311 (Endogone, Glomus, and Sclcrocystis) is a dominant fungal component in the diet of Per- omysciis manicidatus and P. Icucopus at cer- tain times. Similar conclusions can be derived from other studies (e.g., Gerdemann and Trappe 1974, Hamilton 1941, Harling and McClaren 1970, Martell and Macaulay 1981, Schloyer 1976, Whitaker 1966, Williams and Finney 1964). Both mice, however, are basi- cally opportunistic (Lackey et al. 1985, Mer- ritt and Merritt 1980). Whitaker (1966, 1967) found that Pcr- omyscus leiicopiis in Indiana lives essentially in wooded habitat, whereas P. manicidatus occupies primarily nonwooded habitat. This may account for the 15 taxa of hypogeous, ectomycorrhizal Ascomycetes and Ba- sidiomycetes in the diet of P. leucopus from Iowa (Table 2) compared with the 3 taxa of these fungi in the diet of P. manicidatus from Iowa. Hypogeous Ascomycetes and Ba- sidiomycetes tend to produce relatively large, odoriferous sporocaqjs, whereas Zygo- mycetes (Endogonaceae) produce small sporocarps with slight odor or none. Howard and Cole (1967) and Howard et al. (1968) demonstrated that P. manicidatus not only has an excellent sense of smell but also relies on this sense to detect food. Acute olfaction, coupled with nonwooded or lightly wooded habitat over much of its range, may help ex- plain the apparent selectivity by P. manicida- tus for fungi in the Endogonaceae. The four species oiPeromyscus appear to be opportunists in diet (Douglas 1969, Drick- amer 1976, Whitaker 1966, 1967, Wilson 1968). In nonforested areas their concentra- tion on VA-mycorrhizal fungi as food can help plants that require such mycosymbionts be- cause the mice disperse viable spores through defecation (Rothwell and Holt 1978, Trappe and Maser 1976). The same would be true in coniferous forests where dispersal of VA-my- corrhizal spores by mice would enhance es- tablishment of early successional and under- story vegetation. Our laboratory data also show that spores of ectomycorrhizal fungi (in coniferous forests) are viable after passage through the intestinal tracts of P. manicida- tus. Other rodents appear to be more impor- tant, however, than P. ;nrt/H'cfv/«ff/.s for disper- sal of ectomycorrhizal spores in coniferous forests (Kotter and Farentinos 1984, Maser et al. 1978, 1985, Trappe and Maser 1977, Ure and Maser 1982). Perhaps the main importance of my- cophagy by members of the genus Per- omyscus is that, to some extent, they are con- noisseurs of endomycorrhizal fungi in the Endogonaceae. This is potentially important, particularly in nonforested habitats, because these mice may play a role in plant succession by dispersing viable spores on vegetating mining spoils (Aldon 1975, Rothwell and Holt 1978), by helping native vegetation become established in severely disturbed areas that are inhabited primarily by a few Old World, nonmycorrhizal species (Miller 1979), and by helping to maintain already-established healthy native plants (Green et al. 1983, Molina et al. 1978, Recce and Bonham 1978, Williams and Aldon 1976). Acknowledgments Nixon Wilson (Department of Biology, University of Northern Iowa, Gedar Falls) col- lected the material from Iowa. Donald K. Grayson and Murray L. Johnson (Burke Mu- seum, University of Washington, Seattle), James M. Trappe (Department of Forest Sci- ence, Oregon State University, Corvallis), and John O. Whitaker, Jr. (Department of Life Sciences, Indiana State University, Terre Haute) read and improved the manuscript. Ginny Bissell typed the various drafts. We appreciate the help. This paper represents a partial contribution (no. 28) of the project entitled "The Fallen Tree — an Extension of the Live Tree." The project is cooperative among the U.S. De- partment of the Interior, Bureau of Land Management; U.S. Department of Agricul- ture, Forest Service, Pacific Northwest Re- search Station; Oregon State University, De- partment of Forest Science; U.S. Department of Agriculture, Agricultural Research Service; and Oregon Department of Fish and Wildlife. Literature Cited Aldon, E. F 197.5. EiuloniNxorrhizae enhance survival and growth of fourwing sahhush on coal mine spoils. USDA For. Serv. Res. NoteRM-24. Rocky Mountain Forest and Range Expt. Sta., Fort Collins, Colorado. 2 pp. 312 Great Basin Naturalist Vol. 47, No. 2 Cook, J C . M S Topping, andT A Stombaugh. 1982. Food habits of Microtus ochro^aster and Per- omyscits maniculatus in .sympatry. Trans. Mis- souri Acad. Sci. 16: 17-23. Douglas, C L. 1969. Comparative ecology of pinyon mice and deer mice in Mesa Verde National Park, Colorado. Univ. Kansas Publ. Mus. Nat. Hist. 18; 421-504. Drickamer, L C 1976. Hypotheses linking food habits and habitat selection in Peroimjsciis. ]. Mammal. 57: 763-766. Flake, L D. 1973. Food habits of four species of rodents on a short-grass prairie in Colorado. J. Mammal. 54: 636-647. FoGEL, R D., AND J M. Trappe 1978. F^ungus consump- tion (mycophagy) by small animals. Northwest Sci. 52: 1-31. Gashwiler, J S 1965. Tree seed abundance vs. deer mouse populations in Douglas-fir clearcuts. Proc. Soc. Amer. For., Detroit, Michigan, pp. 219-222. 1979. Deer mouse reproduction and its relation- ship to the tree seed crop. Amer. Midi. Nat. 102: 95-104. Gerdemann, J W , and] M Trappe 1974. The Endogo- naceae in the Pacific Northwest. Mycol. Mem. 5: 1-76. Green, N E , M D Smith, W D Beams, and E F Al- DON 1983. Influence of vesicular-arbuscular my- corrhizal fungi on the nodulation and growth of subclover. J. Range Manage. 36: 576-578. Halford, D K 1981. Repopulation and food habits of Feroinijscus maniculatus on a burned sagebrush desert in southeastern Idaho. Northwest Sci. 55: 44-49. Hamilton, W J , Jr 1941. The food of small forest mam- mals in eastern United States. J. Mammal. 22: 250-263. Harling, J , and M. McClaren 1970. The occurrence of Endogone macrocarpa in stomachs oiPeromijscus maniculatus. Syesis 3: 155-159. HooVEN, E 1958. Deer mouse and reforestation in the Tillamook Burn. Res. Note 37. Oregon Forest Lands Research Center, Corvallis. 31 pp. Howard, W E., and R. E. Cole 1967. Olfaction in seed detection by deer mice. J. Mammal. 48: 147-150. HowARD.W E , RE Marsh, ANDRE Cole 1968. Food detection by deer mice using olfactory rather than visual cues. Anim. Behav. 16: 13-17. Hunt, G A , andZ Maser 1985. Consumption of hypo- geous fungi by the deer mouse {Peromtjscus maniculatus). Page 272 in R. Molina, ed.. Pro- ceedings 6th North American conference on my- corrhizae. Bend, Oregon. Forestry Research Lab., Oregon State University, Corvallis. King, J. A., ed. 1968. Biology oi Peromyscus (Rodentia). Amer. Soc. Mammal. Special Publ. 2. 593 pp. Kotter, M M ,andR C Farentinos 1984. Formation of ponderosa pine ectomycorrhizae after inoculation with feces of tassel-eared squirrels. Mycologia 76: 758-760. Lackey, J A , D G Huckaby, and B G Ormiston 1985. Peromyscus leucopus. Mammal. Species 247: 1-10. Martell, a. M , AND A L Macaulay 1981. Food habits of deer mice (Peromyscus maniculatus) in north- ern Ontario. Canadian Field-Nat. 95: 319-324. Maser, C, J M Trappe, AND R A Nussbaum 1978. Fun- gal-small mammal interrelationships with empha- sis on Oregon coniferous forests. Ecology 59: 799-809. Maser.Z.C Maser, andJ M Trappe 1985. Food habits of the northern flying squirrel (Glaucomys sabri- nus) in Oregon. Canadian J. Zool. 63: 1084-1088. Merritt, J F , and J M Merritt 1980. Population ecol- ogy of the deer mouse {Peromyscus maniculatus) in the Front Range of Colorado. Annals Carnegie Mus. 49: 113-130. Miller, R M 1979. Some occurrences of vesicular-ar- buscular mycorrhiza in natural and disturbed ecosystems of the Red Desert. Canadian J. Bot. 57: 619-623. Molina, R J , J M Trappe, and G S Strickler 1978. Mycorrhizal fungi associated with Festuca in the western Lhiited States and Canada. Canadian J. Bot. 56: 1691-1695. Osborne, T O , and W A Sheppe. 1971. Food habits of Peromyscus maniculatus on a California beach. J. Mammal. 52: 844-845. Reece, P E , AND C D Bonham 1978. Frequency of endomycorrhizal infection in grazed and ungrazed blue grama plants. J. Range Manage. 31: 149-151. Rothwell, F M . aNdC Holt 1978. Vesicular-arbuscu- lar mycorrhizae established with Glomus fascicu- latus spores isolated from the feces of cricetine mice. USDA Forest Service Research Note NE- 259. Northeastern Forest Expt. Sta., Broomall, Pennsylvania. 4 pp. Schloyer, C R 1976. Changes in food habits of Per- omyscus maniculatus nubiterrae Rhoads on clearcuts in West Virginia. Proc, Pennsylvania Acad. Sci. 50: 78-80. Sullivan, T P 1979a. Repopulation of clear-cut habitat and conifer seed predation of deer mice. J. Wildl. Manage. 43: 861-871. 1979b. Demography of populations of deer mice in coastal forest and clear-cut (logged) habitats. Canadian J. Zool. 57: 1636-1648. Trappe. J M 1981. Mycorrhizae and productivity of arid and semiarid rangelands. Pages 581-599 in Ad- vances in food producing systems for arid and semiarid lands. Academic Press, Inc., New York. Trappe, J M , and R. D. Fogel. 1977. Ecosystematic functions of mycorrhizae. Pages 205-214 in J. K. Marshal, ed.. The belowground ecosystem: a syn- thesis of plant-associated processes. Range Sci. Dept. Sci. Ser. 26. Colorado State University, Fort Collins. Trappe, J M , andC. Maser. 1976. Germination of spores of Glomus macrocarpus (Endogonaceae) after pas- sage through a rodent digestive tract. Mycologia 68: 433-436. 1977. Ectomycorrhizal fungi: interactions of mushrooms and truffles with beasts and trees. Pages 165-178 in T. Walters, ed.. Mushrooms and man: an interdisciplinary approach to mycol- ogy. Linn Benton Community College, Albany, Oregon. April 1987 Maser, Maser: Micophagyin Mice 313 Ure, D. C , AND C Maser 1982. Mycophagy of red- backed voles in Oregon and Washington. Cana- dian J. Zool. 60: 3307-,3315. Whitaker, J. O , Jr 1966. Food of Mus musculus. Per- (mujsctis maniculatus hairdi and Peromtjscus leu- coptis in Vigo County, Indiana. J. Mammal. 47: 473-486. 1967. Habitat relationships of four species of mice in Vigo County, Indiana. Ecology: 48: 867-872. Williams. O 1959. Food habits of the deer mouse. J. Mammal. 40:415-419. Williams, O , and B A Finney 1964. Endogone — food for mice. J. Mammal. 45: 265-271. Williams. S E , and E F Aldon 1976. Endomycor- rhizal (vesicular-arbuscular) association of some arid zone shrubs. Southw. Nat. 20: 437-444. Wilson, D E. 1968. Ecological distribution of the genus Perovujscus. Southw. Nat. 13: 267-274. BEE VISITORS OF SWEETVETCH, HEDYSARUM BOREALE BOREALE (LEGUMINOSAE), AND THEIR POLLEN-COLLECTING ACTIVITIES' Vinct'iit J. Tepedino" and Mark Stackliousc' Abstract. — The native liee fauna visiting and pollinating a population of svveetveteh in Grand Teton National Park was surveyed. The papilionaceous flowers were exploited l)y 37 bee species, most ofvvhich had long niouthparts. Most species collected pollen as well as nectar. Bees foraged most hea\ il\ in early afternoon when pollen was most abundant. However, there was no indication that bee species were competing for limited pollen resources; there was no difference among three time periods in percent sweetvetch pollen carried in the scopal pollen loads of bees nor was there any evidence that some species were displacing the foraging times of others. The advantages of developing a native species as a commercial pollinator of sweetvetch are discussed and several potential candidates are mentioned. Legumes are important components of rangeland ecosystems because of their ability to enrich the soil by fixing nitrogen and be- cause of the nutritional content and palatabil- ity of some to livestock and vvildliie. These characteristics have led to suggestions that productivity of rangelands can be increased by using mixtures of grasses and legumes rather than grasses alone (Cook 1983, Rum- baugh and Townsend 1985). Among the many species of legiune under study for potential inclusion in the managed rangeland community is sweetvetch, Hedy- sariim boreale Nutt., a perennial torb of hol- arctic distribution. Sweetvetch fixes nitrogen and is both nutritious and palatable to grazing animals (Rumbaugh and Townsend 1985). Two subspecies grow in North America: ssp. boreale in the western United States and southern British Columbia and Alberta; and ssp. mackenzii in northern Canada, the Yukon Territory, and Alaska (Northstrom and Welsh 1970). Subspecies boreale is likely to be most valuable as a rangeland plant because of its geographic distribution and habitat recjuire- ments. Although sweetvetch is an excellent seed producer (Rumbaugh and Townsend 1985), seed for use in rangeland seedings and in revegetating disturbed sites is both costly and scarce. At present, seed is primarily collected from wild plants in natiual habitats; commer- cial production has hardly begun. Indeed, aside from a study of ssp. mackenzii in the Yukon Territory (Kowalczyk 1973), there is little known of the reproductive biology and pollination ecology of sweetvetch. Kowalczyk (1973) reported that in ssp. mackenzii the pinkish to purple papilionaceous flowers were partially self-fertile but required visitation by insects, particidarly bumblebees (Botnbus), to set seed. The pollination ecology of ssp. boreale may differ because the flowers are smaller than those of ssp. mackenzii (North- strom and Welsh 1970) and may be less attrac- tive to long-tongued bumblebees. This study describes the bee fauna visiting a natural population oiHechjsarum boreale bo- reale in Grand Teton National Park, Wyo- ming. In particular, we report on the relative abundances of bee visitors at different times of day and their pollen-collection activities. Methods We selected an undisturbed population of several hundred Hedysarum boreale boreale growing among Artemisia tridentata and other subshrubs on the rocky, south- and west-facing slopes of Spread Creek Hill, Teton Co., Wyoming, at about 2,200 m alti- tude. Systematic collections of bees were made on five days from late June to mid-July dining the peak blooming period. To assure a representative temporal sample of flower visi- tors, two collectors were active during each of 'Contribution from Utah Agricultural E.xperiTni-nt Station, L'tali State Universitv, Logan, I'tali 84322-4810, Journal Paper No, ,33.5.5, and L'SDA-A.gricul- tural Research Service. Bee Biolog\- and Systematica Lal)orator> , Utah State University. Logan. Utah 84.322-5310 -USDA-Agricultural Research Service, Bee Biology and Systeniatics Laboratory, Utah State Uni\ersit\ , Logan, Utah 84.322-.531(l. ^U.53 Emerson Avenue. Salt Lake Citv, Utah 84105-2527. 314 April 1987 TePEDINC), StACKHOUSE: SWEE'H'ETCn POLLINATORS 315 Table 1. Total number of bees captured by species and number of females captured by time period (N). P = number of females carrying pollen; % pollen is the average percent sweetvetch pollen carried in the scopa. Total no. bees captured 6 6 9 9 N (?) % Pollen No. females captured Time period 2 3 No time recorded N (P) % Pollen N (P) % Pollen N (P) % Pollen Andrenidae Aridrciia spp. Anthophoridae Nomada spp. Tetndonia f rater {Cresson) Apidae Apis mellifera Linnaeus Bomhiis appositus Cresson Boinhus hifarius Cresson Bomhus fcrv idus (Fdhncius) Bomhus flatifrons Cresson Boiid>us ') Hoplitis producia (Cresson) Mcgachdc fh 0.25). These results held for all abundant bee species; there was no indication that any spe- cies specialized in foraging at a particular time or that time was a resource which bees were partitioning. Our second prediction, that the percentage of sweetvetch pollen in the pollen loads would be highest during the second collection pe- riod, was not supported by the data; When all pollen-collecting bees were grouped, irre- spective of species, there were no differences among time periods in the percentage of sweetvetch pollen in bee pollen loads (ANOV on arcsin transformed data: F = 1.89, d.f. = 2,175, P = 0.15). This result also held when the more abundant species were examined individually: for Tetralonia frater, the mean percentage of sweetvetch pollen ranged only from 78.7% to 80.1% across the three time periods. Results for other species such as Megachile gemula Cresson, M. inelanophaea Smith, and Osmia hucephala Cresson were similar. Discussion In Grand Teton National Park, sweetvetch flowers are very attractive to a variety of bee species with long mouthparts (Table 1). This is not surprising because the long, narrow, closed corolla tube of papilionaceous legume flowers makes their rewards, particularly nec- tar, unavailable to species with short mouth- parts. Our collections on ssp. horeale in the Tetons yielded a far more diverse bee fauna than that found by Kowalczyk (1973) on ssp. mackenzii in the Yukon Territory. In the Yukon, ssp. mackenzii was visited and polli- nated almost exclusively by bumblebees. In- deed, the Osmia, Megachile, and Anthidium that Kowalczyk (1973) did find were so rare that he did not even bother to have them identified to species. While bumblebees were also abundant on sweetvetch flowers in the Tetons, other species with long mouthparts were more numerous. The most straightfor- ward explanation for this difference is simply that bumblebees comprise an increasing pro- portion of the bee fauna with increasing lati- tude (Morse 1982). This transition is a result of April 1987 Tepedino, Stackhouse: Svveetx'etch Pollinators 317 an increase in bumblebee numbers with lati- tude but rather to a gradual decline in the diversity and abundance of solitary species, presumably because of their inability to adapt to the harsh climate. It is not farfetched to speculate that the decline, with increasing latitude, of solitary bee pollinators of sweetvetch has influenced the length of the corolla in ssp. mackenzii and may have played a role in its separation from ssp. horeale. Indeed, pollinators have been implicated as agents of speciation in many plant taxa (Levin 1971). We suggest that the longer corolla in ssp. inackenzii gradually evolved as an adaptation to the larger, and more abundant and reliable, bumblebee pol- linators whose mouthparts are generally longer than those of solitary species. As the corolla lengthened over time, the flowers would gradually become less exploitable by solitary species until, eventually, only bum- blebees could forage from them with consis- tent profit. There would be no such selective pressure on ssp. horeale because of the size, diversity, and reliability of nonbumblebee populations. Should sweetvetch prove to be a desirable species for rangeland seedlings or revegetat- ing disturbed areas, commercial seed-grow- ing operations will be needed. Depending on the area and situation under which commer- cial operations are conducted, it may be nec- essary to provide a pollinating insect to obtain maximum seed production. If the area under cultivation is small and is adjacent to natural habitat, then it is probable that sweetvetch is sufficiently attractive to native bees to require no special provision for pollination. For exam- ple, a three-acre planting surrounded by rangeland in western Wyoming attracted nu- merous megachilid and apid species and pro- duced copious seed. If plantings are larger or are located in cultivated areas where bees are scarce, it may be necessary, or desirable, to develop a solitary bee species that can be managed as a commercial pollinator. Pollina- tion by solitary species would be especially appropriate for sweetvetch because plantings are likely to be relatively small and bloom lasts only about a month. Thus, a pollinator that has but one generation a year and flies for a short period of time (a few weeks) would be ideal. Small populations should also be readily ob- tainable, and the bee should be attracted to the plant. Obviously, several species listed in Table 1 possess these characteristics. Of these, some are particularly amenable to ma- nipulation because they nest in existing holes in wood (Parker and Torchio 1980). Examples are Megachile gemula and Osmia albolateralis Cockerell, O. bruneri Cockerell and O. hu- cephala. Such species require minimal care and attention because they spend 10 to 11 months of each year as immatures in their nests. Any attempt to develop a solitary bee as a commercial pollinator for sweetvetch would do well to begin with one of these species. Acknowledgments We thank K. L. Diem for allowing us to use the facilities of the University of Wyo- ming-National Park Service Research Center in Moran, Wyoming; S. Jennings, J. Hen- nebold, and M. Klomps for pollen identifica- tion and data tabulation; G. E. Bohart for determining the Osmia species and confirm- ing the bumblebee identifications; and F. D. Parker and T. L. Griswold for identifying the other megachilids. The manuscript benefited from reviews by F. D. Parker, M. D. Rum- baugh, and S. L. Welsh. Literature Cited Beattie. a J 197L A technique for the study of insect- borne pollen. Pan-Pac. Entomol. 47: 82. Cook, C W 1983. "Forhs need proper ecological recog- nition. Rangelands 5: 217-220. Faegri. K . AND L VAN DER PijL. 1971. The principles of pollination ecology. 2cl ed., rev. Pergamon Press, New York. Frankel. R , AND E Galun. 1977. Pollination mecha- nisms, reproduction and plant breeding. Springer- Verlag, New York. KowALCZYK, B F 1973. The pollination ecology of Hedijsarum alpinitm L. var. americanum (MCHX.) and H. horeale NVTT. var. mackenzii (Richards.) C. L. Hitchc. in the Kluane Lake area of the Yukon Territory, Canada. Unpublished the- sis, Lhiiversity of North Carolina, Chapel Hill. 73 pp. Levin. D. A 1971. Origin of reproductive isolating mech- anisms in flowering plants. Taxon 20: 91- 113. LlNSLEY. E. G 1978. Temporal patterns of flower visita- tion by solitary bees, with particular reference to the southwestern United States. J. Kansas Ento- mol. Soc. .51:531-546. Morse, D H 1982. Behavior and ecology of bumble bees. Pages 245-.322 in H. R. Hermann, ed.. Social insects. Vol. 3. Academic Press, New York. 318 Great Basin Naturalist Vol. 47, No. 2 NoRTHSTROM, T. E., AND S L. WELSH. 1970. Revhsion of 33.5. Wa.shington, D.C. the Hedysarum horeale comple.x. Great Ba.sin Rumbaugh, M. D., and C. E. Townsend. 198.5. Range Nat. 30: 109-1.30. legume selection and breeding in North America. Parker, F. D, AND P. F. Torc:hk). 1980. Management of Pages 137-147 in Proceedings: selected papers wild bees. Pages 144-160 in Beekeeping in the presented at the .30th annual meeting of the Soci- United States. USDA Agricultural Handbook No. ety for Range Management. OBSERVATIONS ON NATURAL ENEMIES OF WESTERN SPRUCE BUDWORM {CHORISTONEURA OCCIDENTALIS FREEMAN) (LEPIDOPTERA, TORTRICIDAE) IN THE ROCKY MOUNTAIN AREA Howard E. Evans' Abstract — Three species of predators and parasites were found associated with western spruce budworm {Choris- toneura occidentalis Freeman) (Lepidoptera, Tortricidae) in Larimer Co., Colorado. These were: Ancistroceriis antilope (Panzer) (Hymenoptera, Vespidae), Gonioztis gracilicornis (Kiefifer) (Hymenoptera, Bethylidae), and Cero- masia aiiricaudata Townsend (Diptera, Tachinidae). The first two species stored caterpillars in wooden trap nests, while the third was reared from final instar hudworms. Over the past several years I have had an opportunity to observe several predators and parasites of the western spruce budworm (Choristonetira occidentalis Freeman) near my home, 23 km west of Livermore, Larimer Co., Colorado. This is an area of open pon- derosa pine-Douglas-fir forest at 2,300 m ele- vation. Spruce budworms occur here regu- larly on Douglas-fir, in some years causing extensive damage and sometimes tree mortal- ity. Infestations were, however, moderate to low during the period of study (I985-I986). Budworms attain final instar during June and pupate in early July. Methods Some records were obtained by collecting and rearing last instar larvae, but more were obtained from trap nests. Trap nests consisted of pieces of pine 15 cm long and 2 cm square, with a groove (6 or 9 mm in diameter) on one side to which a strip of Plexiglas was taped. A wooden strip was then placed over the Plexi- glas; the strip could easily be removed for examination of trap nest contents. Traps were placed 0.3 to 2.5 m above the ground in wood piles or in living or dead trees or attached to my house. They were accepted by several species of bees and wasps, the most abundant of which were two species o( Ancistroceriis, adiabatus (Saussure) and antilope (Panzer) (Vespidae, Eumeninae). Both are well-stud- ied species that make a series of cells sepa- rated by mud partitions and provisioned with larvae of Microlepidoptera (references in Krombein 1979). Only A. antilope used spruce budworms as prey. Results Ancistrocerus antilope (Panzer) (Vespi- dae). Eleven trap nests with a total of 49 cells were provisioned by females of this species in 1985 (none in 1986). Nests with bores of 6 to 9 mm were accepted, cell lengths varying from 8 to 18 mm (mean 11.8, N = 30) in bores of 8 to 9 mm and from 13 to 22 mm (mean 18.0, N = 19) in bores of 6-mm diameter. Each nest had an outer, empty vestibular cell measuring from 8 to 31 mm in length, as well as an outer closure. No accurate count of prey was made in all cells, but of 8 counted the mean was 5.5 per cell. Thus, the total prey in the II nests approximated 270 Microlepidoptera. Of these, 20 (7.4%) were Choristonetira occiden- talis, the remainder several other species of Microlepidoptera. However, 7 of the II nests were provisioned after most of the budworms had pupated. Of 4 nests provisioned prior to 3 July, 8 of the 15 cells contained spruce bud- worms; 24% of the prey consisted of that spe- cies. One nest of 4 cells contained 16 bud- worms (4 per cell), while another of 3 cells contained 3 budworms and 15 other larvae. After 3 July, no spruce budworms were found in any of the nests. Two nests had cells parasitized by cuckoo wasps, Chrysis coerulans Fabricius, and two had cells parasitized by flies of the genus Aino- 'Department of Entomology, Colorado State University, Fort Collins, Colorado 80.523. 319 320 Great Basin Naturalist Vol. 47, No. 2 bia (Sarcophagidae). Both have been reared from Ancistrocerus antilope previously (Krombein 1967). Three ichneumon wasps, Pimpla spatulata Townes, also emerged from one nest. This species was reared by Krom- bein (1967) from members of two other genera of Vespidae (Eumeninae) in New York. In eastern North America, spruce bud- worms {Choristoneura fumiferana [Cle- mens]) have been found to serve as prey of eumenine wasps on several occasions. Fye (1962, 1965) recorded Ancistrocerus adiaba- tus (Saussure), A. catskill (Saussure), and Eu- odynerus leucomelas (Saussure) preying on budworms in Ontario. He felt that it might be possible to take advantage of the wasp's searching abilities to sample populations of this and other species of Microlepidoptera. Jennings and Houseweart (1984) found A. catskill and E. leucomelas provisioning trap nests with spruce budworms in Piscataquis Co., Maine. Ancistrocerus antilope also ac- cepted their traps but provisioned only with Nephoterix sp. (Pyralidae). Western spruce budworms have not previously been reported as prey of A. antilope. Goniozus gracilicornis (Kieffer) (Bethyli- dae). On 5 July 1986 I collected a trap nest (3-mm-diameter bore) that contained three cells of a species of Trypoxijlon (Sphecidae). The cells were at the inner end of the bore, each containing paralyzed spiders and a wasp egg and closed off with a mud partition. Out- side of the last partition but 60 mm from the bore opening (which had not been closed) was a paralyzed last instar larva of the western spruce budworm. The larva was 19 mm long and of a thickness such that it barely fit within the trap nest. It bore 20 elongate eggs, each about 0.8 mm long. They were attached longi- tudinally over much of the dorsal length of the thorax and abdomen. The eggs had not hatched on the following day. However, five days later the larvae had already completed their development, and the remains of the caterpillar were covered with white, silken cocoons. (I was away during these five days and did not observe the progress of the lar- vae.) Sixteen days later nine female Goniozus gracilicornis appeared in the rearing container. I suspect that several more of these minute, flat- tened wasps had escaped from the container. It remains a puzzle as to how the budworm larva had been placed in a trap nest with a bore this small. The trap nest had been at- tached to a ponderosa pine branch, about a meter above the ground. Pines usually are not hosts of spruce budworms; presumably the larva came from a nearby Douglas-fir. The bethylid wasps measure about 3 mm long, and it is difficult to conceive of a female wasp dragging a prey this large any distance. How- ever, there are records of Bethylidae of sev- eral genera dragging their prey into places of concealment, even though the prey was com- monly much larger than the wasp (Yamada 1955, Rubink and Evans 1979). Gordh (1976) remarked that species of Goniozus have not been observed moving their prey, but he did note a female G. gallicola Fonts attempting to drag paralyzed prey to the side of a container. Also, the type specimen of G. raptor Evans was taken "carrying larva of pink bollworm by the head" (Evans 1978). The ability of bethylids to drag their paralyzed prey into a protected place may account for the fact that several species have been reared from stems and galls. Goniozus gracilicornis has been reared from species of Gelechiidae and Tortricidae (Evans 1978), but from species attacking crop plants rather than trees. Another species of Goniozus, floridanus (Ashmead), has been reared from Choristoneura rosaceana Harris, which attacks broad-leafed trees. Most spe- cies oiGoniozus not only parasitize a variety of Microlepidoptera but also occur in diverse habitats. Goniozus gracilicornis is not listed as a parasite of western spruce budworms in Oregon by Carolin and Coulter (1959). Ceromasia auricaudata Townsend (Tach- inidae). In 1985 and again in 1986 I collected 20 final instar larvae of western spruce bud- worm and reared adults from them. In each year two tachina flies also emerged; all four were Ceromasia auricaudata. This species was one of the more prevalent of 10 tachinid species reared from Choristoneura occiden- talis in Oregon (Carolin and Coulter 1959). Despite the small sample size, it seems safe to categorize this species as one of the more impor- tant parasites of the western spruce budworm in the east central Rocky Mountain area. Discussion Although these studies were made casually in the course of other research, they add a few April 1987 EvANS: Western Spruce Budworm Predators 321 details to the extensive literature on the natu- ral enemies of the western spruce budworm. Jennings and Crawford (1985) suggest several ways in which the effect of natural enemies can be enhanced, such as providing an abun- dance of flowering plants that serve as nectar sources and providing nest boxes for birds. In the Rocky Mountain area, mountain chick- adees, which are major predators on larvae, readily accept nest boxes. Trap nests for wasps can also be made cheaply and, if placed in the field well before budworms pupate, can provide a means of assessing budworm abun- dance. Trap nests may also provide homeown- ers with an additional means of protecting their trees. Acknowledgments I thank Mary Alice Evans for assistance with the field work and N. E. Woodley (Sys- tematic Entomology Laboratory, US DA) for identifying the Ceromasia. Literature Cited Carolin, v. M., and W K. Coulter 1959. The occur- rence of insect parasites ofChoristoneura fttmifer- ana (Clem.), in Oregon. J. Econ. Entomol. 52; 550-555. Evans. H E 1978. The Bethyhdae of America north of Mexico. Mem. Amer. Entomol. Soc. 27: 1-332. Eye. R E 1962. Predation of lepidopterous larvae by solitary wasps. Bimonthly Progress Rpt., Canada Dept. Forestry, Forest Entomol. Pathol. Branch 18: 2-3. 1965. The biology of the Vespidae, Pompilidae, and Sphecidae (Hymenoptera) from trap nests in northwestern Ontario. Canadian Entomol. 97: 716-744. GoRDH, G. 1976. Goniozus ^allicola Fonts, a parasite of moth larvae, with notes on other bethylids (Hy- menoptera: Bethylidae; Lepidoptera: Gelechi- idae). U.S. Dept. Agric, Agric. Res. Service, Tech. Bull. 1524. 27 pp. Jennings, D T , and H S Crawford. Jr 1985. Predators of the spruce budworm. U.S. Dept. Agric, Forest Service, Agric. Handbook 644. 77 pp. Jennings, D T . and M W Houseweart. 1984. Preda- tion by eumenid wasps (Hymenoptera: Eu- menidae) on spruce budworm (Lepidoptera: Tort- ricidae) and other lepidopterous larvae in spruce-fir forests of Maine. Ann. Entomol. Soc. Amer. 77: 39-45. Krombein, K V 1967. Trap-nesting wasps and bees: life histories, nests, and associates. Smithsonian Press, Washington, D.C. .570 pp. 1979. Superfamily Vespoidea. In K. V. Krombein et al. , Catalog of Hymenoptera in America north of Mexico. Vol. 2. Aculeata. Smithsonian Press, Washington, D.C. RuBiNK, W L . AND H E Evans 1979. Notes on the nesting behavior of the bethylid wasp, Epyris eri- ogoni Kieffer, in southern Texas. Psvche 86: 313-319. Yamada. Y 19.55. Studies on the natural enemy of the woollen pest, Anthremis verbasci L. (Allepyris micnmetirus Kieffer) (Hymenoptera, Bethylidae). Mushi 28: 1,3-30. PLANT COMMUNITY ZONATION IN RESPONSE TO SOIL GRADIENTS IN A SALINE MEADOW NEAR UTAH LAKE, UTAH COUNTY, UTAH Jack D. Brotherson Abstract — Patterns of zonation along a saline meadow slope were studied. Different species associations were distributed in five zones along the slope which paralleled Utah Lake. The five zones, distinguished on the basis of dominant species and/or life form, were: saltgrass-annual weed, saltgrass-alkaligrass, saltgrass-forb, saltgrass, and spikerush. Soil, vegetation, and plant species data were taken. Patterns of change with respect to these factors were observed along the downslope gradient. Soil pH and soluble salts decreased downslope, while organic matter and moisture increased. Individual ions showed varying patterns. Vegetation and species patterns also varied with slope position. Annuals dominated the ridge tops, while sedge and rush cover were restricted to the slope base. Perennial forb distribution was shown to be correlated with elevated levels of micronutrients in the soil. The ecological relationships of halophytic species and their communities within coastal environments are well investigated (Adams 1963, Vogl 1966, van der Maarel and Leer- touwer 1967, Cotnoir 1974, Daiber 1974, Duncan 1974, Godfrey et al. 1974, Hinde 1954, Kraeuter and Wolf 1974, MacDonald and Barbour 1974, Walsh 1974), but less has been done on inland halophytes and their communities (Ungar 1969, Chapman 1974, Hansen and Weber 1975, Skougard and Brotherson 1979). The anatomy of halophytes and their ecological adaptations to saline soils are also well reviewed (Anderson 1974, Cald- well 1974, Hansen 1974). Soil salinity is considered to be the most important variable in controlling halophyte distribution (Ungar 1974). However, salinity in combination with other factors has also been shown to be important in controlling the distribution of halophytic species. For exam- ple, Hutchinson (1982) showed the impor- tance of salinity and salinity-elevational inter- actions to account for variations in halophyte distributions. A halophyte is defined as a spe- cies which can tolerate levels of salinity greater than 0.5% (Barbour 1970, Chapman 1974). Few species are believed to be obligate halophytes (Ungar et al. 1969, Barbour 1970, Ungar 1974). Hydrogen ion concentration (pH) has also been suggested as an important determinant of halophyte species distribution (van der Maarel and Leertouwer 1967, Stolfelt 1972, Skougard and Brotherson 1979). Alterna- tively, pH may not be as closely correlated to biological phenomena since broad overlaps in pH exist between plant communities (Daubenmire 1959a, Ungar et al. 1969). The relations of moisture in determining species composition and distribution have long been studied. Curtis (1955) discusses the use of indicator species in describing commu- nities with environments of varying moisture content. Dix and Butler (1960) state that mois- ture is the principle environmental factor con- trolling species composition in a mesic-dry and dry prairie in Wisconsin. Also, Skougard and Brotherson (1979) discussed the influence of soil moisture as a factor in determining zonation patterns of vascular plants in playa meadows in central Utah. Moisture was noted to be second to salinity in such influence. Van der Maarel and Leertouwer (1967) de- termined soil moisture and organic matter to be positively correlated. This is reasonable since an increase in moisture produces an in- crease in biomass and ultimately more litter and organic matter. The present study was undertaken to de- scribe patterns of zonation along a slope in a saline meadow and to determine which of sev- eral soil factors (texture, salinity, mineral nutri- ents, etc.) tended to influence that zonation. Study Site The study site is located along the west 'Department of Botany and Range Science, Brigham Young University, Provo, Utah 84602. 322 April 1987 Broth ERSON: Plant Community Zonation 323 Fig. 1. Map of study site location along west shore of Utah Lake. shore of Utah Lake at T6S, RIE, S32 (Salt Lake base and meridian), Utah County, Utah, approximately L4 km south of Pelican Point (Fig. 1). Zonation within the meadow is visu- ally apparent since different species associa- tions are discretely distributed along a mild slope which parallels the lake. Five zones are distinguishable on the basis of the most obvi- ous species and/or life form: saltgrass-annual weed, saltgrass-alkaligrass, saltgrass-forb, saltgrass, and spikerush (Fig. 2). The first four zones occur along a gradient moving downslope and away from the lake with a ver- tical drop of 2.5 m. The fifth zone (farthest from the lake) rises approximately 3.0 m. M.jlTerials and Methods Fifteen 5 x 15 m plots (three per zone) were placed along the slope. Each plot was subsam- pled by 10 quarter-meter-square (}uadrats. Total living plant cover, plant cover by life form (i.e., perennial forbs, perennial grasses, sedges, rushes, annual grasses, annual forbs). litter, and bare soil were ocularly estimated from each quadrat following a procedure sug- gested by Ostler et al. (1981). Cover for all plant species encountered was also estimated using the cover-class categories suggested by Daubenmire (1959). Three soil samples taken in each plot (from opposite corners and the center) from the top 20 cm of soil by means of a tube soil probe were later combined for laboratory analysis. This depth was considered adequate because Christie (1979), with respect to grasslands, found that the top layer of soil is the region of most active mineral uptake. Soil samples were placed in zip-type plastic bags to retain mois- ture. Percent soil moisture was obtained by weighing fresh soil, drying at 90 C for 72 hours, and reweighing (Skougard and Broth- erson 1979). Soil samples were analyzed for texture (Bouyoucos 1951), pH, soluble salts, mineral composition, and organic matter. Soil reac- tion was taken with a glass electrode pH me- ter. Total soluble salts were determined with a Beckman electrical conductivity bridge. A 1:1 soil-water paste (Russel 1948) was used to determine pH and total soluble salts. Soils were extracted with 1.0 normal neutral am- monium acetate for the analysis of calcium, magnesium, potassium, and sodium (Jackson 1958, Hesse 1971, Jones 1973). Zinc, man- ganese, iron, and copper were extracted from the soils by use of DTPA (diethylenetriamine- penta-acetic acid) extracting agent (Lindsay and Norvell 1969). Individual ion concentra- tions were determined using a Perkin-Elmer Model 403 atomic absorption spectrophoto- meter (Isaac and Kerber 1971). Soil phospho- rus was extracted by sodium bicarbonate (Olsen et al. 1954). Total nitrogen analysis was made using macro-Kjeldahl (Jackson 1958). Organic matter was determined by total car- bon measurement via burning 10 g of soil sample at 950 C in a LECO medium tempera- ture resistance furnace following Allison (1965). Plant nomenclature follows Arnow et al. (1980) for the dicotyledons and Cronquist et al. (1977) for the monocotyledons. Data analysis consisted of computing means, standard deviations, and coefficients of variation for all measured biotic and abiotic variables (Ott 1977). Correlation coefficients were determined for each combination of all 324 Great Basin Naturalist Vol. 47, No. 2 Saltgrass-Annual Alkaligrass Spikerush 1 20 feet Fig. 2. Graphic representation of slope depicting vegetative zonation patterns on the study site. Table 1. Site factors along with their means and standard deviations found along a slope with respect to vegetation zones in a saline meadow. Zone 1 is saltgrass-annual at the ridge top; Zone 2 is saltgrass-alkaligrass at the slope shoulder; Zone 3 is saltgrass-forb at the slope base; Zone 4 is saltgrass at the slope bottom; and Zone 5 is spikerush (see Fig. 2). Zone Site factor 1 2 3 4 5 General soil factors: Percent sand 10.60 ±6.70 11.73 ±5.47 24.07 ±1.57 34.93 ±12.03 13.07 ±3.87 Percent silt 55.00 ±0.00 46.67 ±2.89 47.53 ±12.06 41.10 ±5.70 48.33 ±2.89 Percent clay 34.40 ±0.70 ±41.60 ±8.34 ±28.40 ±11.52 ±23.97 ±9.45 ±38.60 ±6.75 Percent fines 89.40 ±0.70 88.27 ±5.47 75.93 11.57 65.07 ± 12.03 86.93 ±3.87 Percent organic matter 17.08 ±1.10 17.59 2.10 24.14 ±3.73 24.36 3.48 32.70 16.81 pH 8.70 ±0.11 8.47 ±0.14 7.91 ±0.02 7.73 ±0.13 7.66 ±0.11 Soluble salts (ppm) 20,753.33 ±4,646.90 14,480.67 ±6,065.71 8,129.00 ±711.45 3,382.67 ±497.29 4,002.67 ±351.48 Soil moisture (%) 25.9 ±0.67 31.1 ±2.3 34.0 ±5.5 39.3 ±2.5 51.7 ±3.4 Soil mineral nutrients: Nitrogen (%) 0,142 ±0.019 0.227 ±0.041 0.398 ±0.082 0.585 ±0.080 0.282 ±0.123 Phosphorus (%) 15.80 ±3.06 8.0 ±1.23 26.03 ±3.00 27.93 ±1.42 10. 13 ±4.96 Calcium (ppm) 82.688.00 ± 16,566.98 78,378.67 ±22,777.65 14,592.00 ± 1,336.36 15,753.33 ±994.23 80,256.00 ±8,183.00 Magnesium (ppm) 1,000.00 ±159.3 1,354.67 ±52.05 485.33 ±169.01 757.33 ±33.31 685.33 ±110.37 Sodium (ppm) 2,032.00 ±115.38 2,330.67 ±710.03 912.00 ±120.80 1,197.33 ±383.44 1,122.67 ±304.56 Potassium (ppm) 893.33 ±92.03 1,005.33 ± 137.95 509.33 ±145.40 536.00 ±188.13 576.00 ±227.82 Iron (ppm) 1.36 ±0.08 1.41 ±.032 35.57 ± 12.04 62.67 ±40.03 1.84 ±0.32 Manganese (ppm) 9.35 ±1.11 10.75 ±1.82 10.61 ±2.04 14.92 ±7.57 10.82 ±5.74 Zinc (ppm) 1.60 ±0.25 0.92 ±0.19 3.89 ±2.38 4.79 ±1.67 0.62 ±0.12 Copper (ppm) 1.60 ±0.45 2.77 ±0.64 4.79 ±1.24 5.94 ±1.10 2.49 ±0.68 April 1987 BROTHERSON: PlANT COMMUNITY ZoNATION 325 Table 1 continued. Zone Site factor 1 2 3 4 5 BlOTIC FACTORS: Perennial grass cover (%) 30.6 73.7 43.2 99.0 20.2 ±6.7 ±6.8 ±10.0 ±1.6 ±13.2 Perennial forb cover (%) 14.3 0.6 48.1 0,0 20.1 ±3.2 ±0.6 ±13.3 ±0.0 ±4.8 Sedge cover (%) 0.0 0.1 6.4 0.1 11.1 ±0.0 ±0.0 ±4.5 ±0.0 ±1.4 Rush cover (%) 0.0 0.0 0.0 0.9 47.1 ±0.0 ±0.0 ±0.0 ±1.5 ±15.8 Annual forb cover (%) 55.8 25.7 0.8 0.1 0.1 ±7.6 ±7.3 ±1.2 ±0.0 ±0.0 Mean number of species/stand 5.00 9.00 10.33 2.67 8.00 ±0.00 ±1.73 ±1.53 ±1.53 ±1.00 Mean number of native 3.00 7.00 8.67 2.67 6.67 species/stand ±0.00 ±1.00 ±1.53 ±1.53 ±0.58 Mean number/ introduced 2.00 2.00 1.67 0,0 1.33 species/stand ±0.00 ±1.00 ±0.58 ±0,0 ±0.58 Native species 60.00 78.67 83.67 100,00 84.00 (% of total no.) ±0.0 ±8.08 ±6.03 ±0,00 ±5.29 Introduced species 40.00 21.33 16.33 0,00 16.00 (% of total no.) ±0.0 ±8.08 ±6.03 ±0,00 ±5.29 Species diversity 1.51 1..35 1.78 0.06 1.57 Percent COVER: Native species 55.67 97.33 92.00 100.00 81.33 ±17.21 ±1.53 ±12.17 ±0.0 ±7.02 Introduced species 44.33 2.67 8.00 0.00 18.67 ±17.21 ±1.53 ±12.17 ±0.00 ±7,02 site parameters (Cochran and Snedecor 1976). Species diversity was determined based on cover values using Shannon-Weaver s index of diversity (Kempton and Reddenburn 1978). Results and Discussion Results of the soil analyses are given in Table 1. Several patterns of change along the downslope gradient can be observed. For ex- ample: (1) organic matter and percent soil moisture increase; (2) pH decreases; (3) silt, fines, and soluble salts decrease to the salt- grass zone and then increase in the spikerush zone; (4) sand, nitrogen, and copper increase to the saltgrass zone and then decrease in the spikerush zone; (5) magnesium, sodium, and potassium are high in the saltgrass-annual weed and saltgrass-alkaligrass zones and low in the other three zones; (6) phosphorus, iron, and zinc are low in the saltgrass-annual weed and saltgrass-alkaligrass zones, very high in the saltgrass-forb and saltgrass zones, and then low again in the spikerush zone; and (7) calcium is very high in the saltgrass-annual weed and saltgrass-alkaligrass zones, low in the saltgrass-forb and saltgrass zones, and then high again in the spikerush zone. Clay and manganese showed little or no patterns. Although it is not the lowest elevational point of the gradient, the spikerush zone has the highest percent soil moisture levels of any of the zones. This is because the zone overlies seep areas that provide a constant supply of moisture to the surface. Decreasing salinity downslope could be caused by two factors and/or their interac- tions. First, water will drain from the high point in the saltgrass-annual weed zone to the lower saltgrass zone. Also, during years of high moisture, the lower elevation areas are seasonally flooded because of lake fluctua- tions. Increased moisture in the soil will in- crease the leaching effect on salts (Waisel 326 Great Basin Naturalist Vol. 47, No. 2 Table 2. Species and their average percent cover as found in the five vegetative zones of the sahne meadow. Zone 1 is at the ridge top and Zone 4 is at the slope bottom. Zone 5 is upslope from Zone 4 overlying a seep area (see Fig. 2). Zone Species Distichlis spicata 31, 17 41.52 44.49 Kochia scoparia 16.04 0.31 Lepidium perfoliatum 29.66 0.07 0.39 Suaeda depressa 9, ,2.5 8.85 0.29 Cressa truxillensis 13.88 0.11 PuccineUia airoides 32.91 Salicornia rubra 14.15 Iva axillaris 0.07 9.71 Circiuin tindulatum 0,07 0.85 Trifilochin maritima 0.22 10., 33 Polijpo^on monspeliensis 0.02 0,03 J uncus balticus 0.02 6.12 Sporobolus airoides 0.69 Glaux maritima 9.41 Crepis runcinata 13.04 Asclepias speciosa 0,99 Ambrosia psilostacluja 3.29 Hordeum jubatum 0.06 Aster pauciflorus 0.29 Eleocharis palustris Eleocharis rostellata Agropyron repens 99.07 0.04 0.81 18.25 3.15 9.79 17.23 0,60 0.97 0.39 47.94 0.61 1.51 1972). Second, as a soil dries, moisture, to- gether with its dissolved salts, is drawn from the deeper soils. As a result of this "wicking action," water evaporating from the soil sur- face leaves increased concentrations of dis- solved salt in the upper horizon (Waisel 1972, Walter 1973). Consequently, salinity in- creases along the ridge and decreases in the depression. Any increased salinity in the spikerush zone over the saltgrass zone would be due to this same wicking action of evaporat- ing water since the spikerush area overlies a large seep where water is continuously rising to the surface, evaporating, and leaving its salts behind. Cover values (Table 2) showed that, with the exception of a few species, saltgrass {Dis- tichlis spicata) contributed a major propor- tion of the plant biomass in each zone. A broad ecological tolerance is not uncommon for salt- grass. Several studies indicate that saltgrass tolerates salinities ranging from 0.03 to 5.4% with an optimum of approximately 1.5% (Un- gar 1966, Ungar 1974, Hansen et al. 1976, Skougard and Brotherson 1979). However, where saltgrass was the most lush on our sites, salinity levels were only 0.33%. This agrees with Ungar and McClelland (1969), who found saltgrass growing in a dwarfed state in highly saline soils but very lush when salinity was lower. Saltgrass has also been shown to grow across a broad range of pH (Hansen et al. 1974, Ungar 1974, Hansen and Weber 1975, Skougard and Brotherson 1979). Ungar (1974) indicates that pH in saltgrass areas generally ranges between 7.5 and 8.5 but may range from 6.8 to 9.2. This corresponds well with our data wherein saltgrass was found growing at pH levels ranging from 7.6 to 8.7. It has been documented that an increase of water in the soil will in effect raise the pH (Russel 1961). This would indicate that if the mea- sured hydrogen ion concentration decreased slowly with increasing soil moisture, the total hydrogen ion concentration may hold rela- tively constant. If this is the case, the variation in saltgrass cover on our sites is probably not related to changing pH conditions but to other factors. Correlation analyses between cover of salt- grass and different soil factors (Table 3) further explain the above-mentioned relationships. Saltgrass cover showed positive correlation (p < 0.03) to elevated levels of sand, nitrogen, iron, zinc, and copper in the soil. It was nega- tively correlated (p < 0.02) with soil fines, forb cover, sedge cover, and introduced spe- April 1987 BROTHERSON: PLANT COMMUNITY ZoNATION 327 cies cover. The lack of significant correlation to either soluble salts or soil moisture is easily understood in relation to the presence of ele- vated levels of spikerush cover in Zone 5. Saltgrass cover increases steadily downslope and then decreases dramatically in the spikerush zone, whereas soil moisture in- creases steadily across all five zones and solu- ble salts decrease across all five zones. The dramatic increase in spikerush cover and the corresponding decrease in saltgrass cover in the spikerush zone alter the general direction of the saltgrass curve, thus neutralizing the observed trends and therefore the correla- tion. The role of the mineral nutrients in the distribution of saltgrass is not well understood and needs further study. Ungar (1974) discussed halophyte zones and associated species. He states that alkali- grass {Puccinellia airoides) zones are com- monly associated with samphire (Salicornia rubra), Pursh seepweed (Siiaeda dcpressa), and arrowgrass (Triglochi maritima), with samphire and Pursh seepweed generally con- tributing fair amounts of cover to the commu- nity and arrowgrass making up 2% or less of the cover. He also reports soil salinity levels to be between 1.8 and 2.8%, which is consider- ably higher than shown in our study. Other- wise, the associations found in our meadow are consistent with those of Ungar. Percent cover by life form is listed for each zone in Table 1. Annual forb cover is highest on the ridge top and then decreases dramati- cally downslope. Sedge and rush cover are restricted to the wet end of the gradient and show their greatest cover in the spikerush zone. Grass cover spans the total width of the gradient, showing varying degrees of devel- opment depending on the zone. Perennial forbs are generally restricted to the saltgrass- forb and spikerush zones but reach their greatest development in the saltgrass-forb zone. The annual forbs that dominate the ridge top (saltgrass-annual zone) do so because of the dwarfed state of growth in saltgrass, which leaves openings between individual plants where seedlings of species adapted to the more xeric conditions can establish. In addi- tion, they germinate, mature vegetatively, flower, and set seed early in the season when environmental conditions are adequate and before the severe drought of late summer. The distribution of the perennial forbs along the gradient is of interest. Previously forbs have been shown to occupy wetter habi- tats than do grasses (Hironaka 1963, Harner and Harper 1973, Yake and Brotherson 1979). Harner and Harper (1973) suggest that this is due to the growth morphology of grasses and forbs; grass stems depend upon cellulose for support, whereas forbs use turgor pressure to support cells. However, our correlations of percent forbs with percent moisture showed no significant relationships. In fact, the peren- nial forbs in our study showed a bimodal pat- tern of distribution with their greatest impor- tance being at the wet end of the gradient and a lesser peak at the dry end of the gradient (Table 1). The peak at the ridge top is due to a single species, cressa {Cressa triixillensis), whereas the peak in Zone 3 (saltgrass-forb) is due to eight species and the peak in the spikerush zone is due to four species. The total lack of forbs in Zone 4 (saltgrass) and their diminished importance in Zone 5 (spikerush) is best explained by competition. The wetter zones are heavily dominated by saltgrass, common spikerush (Eleochoris palustris), sea milk'wort {Glaiix maritima), and wiregrass (Junciis balticiis), all of which form dense rhi- zome systems in the upper layer of soil, thus increasing the competition for space and therefore reducing the probability of annual or perennial forbs establishing in those zones. A second explanation for the high level of perennial forbs in Zone 3 (saltgrass-forb) could be that of mineral nutrition. It is well known that the presence or absence of particular ions in the soil can affect the growth of a plant and thereby profoundly influence its distribution (Jefferies et al. 1968). For example, fertilizing with nitrogen and phosphorus was found to influence the distribution of salt marsh forbs (Pigott 1968). Also, Thurston (1968) found that the addition of phosphorus, potassium, sodium, and magnesium to native pastures in England altered the distribution of forb spe- cies belonging to the Fabaceae. The presence of high levels of phosphorus, iron, zinc, cop- per, and nitrogen in the soils of Zone 3 could indicate nutrient conditions in the soil which favor the growth and establishment of the perennial forbs. However, further research must be done to fully answer these questions. The distribution of introduced species in the meadow was positively correlated with 328 Great Basin Naturalist Vol. 47, No. 2 Table 3. Results of correlation analysis between site factors (biotic and abiotic) associated with five vegetation zones 1 the saline meadow. Environmental variable Positive correlations Negative correlations Soil moisture (%) Organic matter (%) Soluble salts (ppm) PH Sand (%) Silt (%; Clay (%) Fines (%) Nitrogen (ppm) Organic matter (0.0001) Sedge cover (0.0001) Soil moisture (0.0001) Sedge cover (0.0002) Calcium (0.03) Fines (0.03) Magnesium (0.02) Number of introduced species/stand (0.004) pH (0.0001) Potassium (0.005) Sodium (0.03) Calcium (0.03) Fines (0.03) Magnesium (0.004) Number of introduced species/stand (0.01) Potassium (0.002) Soluble salts (0.0001) Sodium (0.004) Copper (0.004) Saltgrass cover (0.02) Iron (0.02) Nitrogen (0.0001) Grass cover (0.02) Phosphorus (0.02) Zinc (0.01) Introduced species cover (0.02) Number of introduced species/stand (0.004) Forb cover (0.01) Calcium (0.07) Fines (0.0006) Calcium (0.0003) Clay (0.0006) Number of introduced species/stand (0.004) Forb cover (0.01) pH(0.03) Potassium (0.04) Soluble salts (0.03) Copper (0.0001) Saltgrass cover (0.03) Iron (0.004) Grass cover (0.01) Phosphorus (0.0007) Sand (0.0001) Zinc (0.0003) pH (0.0002) Soluble salts (0.002) Sodium (0.03) pH (0.0002) Soluble salts (0.01) Copper (0.03) Nitrogen (0.01) Soil moisture (0.002) Soil organic matter (0.01) Sand (0.03) Copper (0.04) Nitrogen (0.005) Soil moisture (0.0002) Soil organic matter (0.0002) Sedge cover (0.02) Sand (0.03) Calcium (0.0003) Clay (0.0006) Fines (0.0001) Number of introduced species/stand (0.004) Forb cover (0.01) pH (0.03) Potassium (0.04) Soluble salts (0.03) Copper (0.02) Nitrogen (0.05) Grass cover (0.04) Zinc (0.02) Phosphorus (0.01) Sand (0.006) Copper (0.004) Saltgrass cover (0.02) Iron (0.02) Nitrogen (0.0001) Grass cover (0.02) Phosphorus (0.001) Sand (0.0001) Zinc (0.01) Calcium (0.001) Fines (0.0001) Introduced species cover (0.008) Number of introduced species/stand (0.002) Forb cover (0.005) pH (0.005) Potassium (0.02) Soluble salts (0.01) Silt (0.005) Sodium (0.04) April 1987 Table 3 continued. BrOTHERSON: PLANT COMMUNITY ZoNATION 329 Environmental variable Positive correlations Negative correlations Phosphorus (ppm) Calcium (ppm) Magnesium (ppm) Sodium (ppm) Potassium (ppm) Iron (ppm) Manganese (ppm) Zinc (ppm) Copper (ppm) Copper (0.0003) Iron (0.0006) Nitrogen (0.0007) Sand (0.001) Zinc (0.0002) Clav (0.007) Fines (0.0003) Magnesium (0.01) Number of introduced species/stand (0.02) pH(0.03) Potassium (0.01) Soluble salts (0.03) Calcium (0.01) pH (0.004) Potassium (0.0001) Soluble salts (0.02) Magnesium (0.0003) pH (0.004) Potassium (0.0002) Soluble salts (0.03) Calcium (0.01) Fines (0,04) Magnesium (0.0001) Number of introduced species/stand (0.05) pH (0.002) Soluble salts (0.005) Sodium (0.0002) Copper (0.0001) Saltgrass cover (0.03) Manganese (0.02) Nitrogen (0.004) Grass cover (0.03) Phosphorus (0.0006) Sand (0.02) Zinc (0.0001) Copper (0.03) Iron (0.02) Copper (0.0001) Saltgrass cover (0.03) Iron (0.0001) Nitrogen (0.0003) Crass cover (0.03) Phosphorus 10.0002) SandfO.Ol) Saltgrass cover (0.02) Iron (0.0001) Manganese (0.03) Nitrogen (0.0001) Grass cover (0.01) Phosphorus (0.0003) Sand (0.004) Calcium (0.0001) Clay (0.01) Fines (0.001) Magnesium (0.04) Number of introduced species/stand (0.04) Potassium (0.05) Sodium (0.05) Copper (0.0008) Iron (0.001) Nitrogen (0.001) Phosphorus (0.0001) Sand (0.0003) Zinc (0.0005) Phosphorus (0.04) Copper (0.04) Nitrogen (0.04) Soil moisture (0.03) Phosphorus (0.05) Nitrogen (0.02) Phosphorus (0.05) Sand (0.04) Calcium (0.001) Fines (0.02) Number of introduced species/stand (0.01) Forb cover (0.02) Calcium (0.0005) Fines (0.01) Introduced species cover (0.05) Number of introduced species/stand (0.02) Forb cover (0.02) Silt (0.02) Calcium (0.0008) Fines (0.004) Introduced species cover (0.0007) Number of introduced species/stand (0.01) Forb cover (0.004) 330 Table 3 continued. Great Basin Naturalist Vol. 47, No. 2 Environmental variable Positive correlations Negative correlations Grass cover (%) Annual forb cover (%) Perennial forb cover (%) Sedge cover (%) Introduced species cover (%) Number of introduced species/stand Saltgrass cover (%) Zinc (0.0001) Copper (0.01) Saltgrass cover (0.0001) Iron (0.03) Nitrogen (0.01) Sand (0.02) Zinc (0.03) Soluble salts (0.001) pH (0.001) Silt (0.05) Fines (0.05) Calcium (0.05) Magnesium (0.05) Sodium (0,01) Potassium (0.01) Introduced species cover (0.01) Species diversity (0.05) Soil moisture (0.0001) Soil organic matter (0.0002) Fines (0.002) Silt (0.02) Calcium (0.002) Fines (0.004) pH (0.01) Potassium (0,05) Soluble salts (0.004) Silt (0.04) Copper (0.01) Iron (0.03) Nitrogen (0.03) Grass cover (0.0001) Sand (0.02) Zinc (0.003) pH (0.04) Soluble salts (0.03) Silt (0.02) Sodium (0.04) Fines (0.02) Introduced species cover (0.009) Forb cover (0.0001) Sedge cover (0.03) Silt (0.04) Soil moisture (O.OI) Organic matter (0.01) Sand (0.05) Nitrogen (0.01) Zinc (0,01) Sedges (0,05) Saltgrass (0.05) Magnesium (0.05) Sodium (0.05) Grass cover (0.03) Potassium (0.05) Saltgra.ss cover (0.008) Grass cover (0.03) pH (0.02) Copper (0.007) Saltgra.ss cover (0.02) Nitrogen (0.008) Grass cover (0.009) Zinc (0,005) Copper (0.01) Iron (0.01) Nitrogen (0.002) Phosphorus (0.04) Sand (0.004) Zinc (0.02) Fines (0.02) Introduced species cover (0.02) Forb cover (0.0001) Sedge cover (0.008) silt, fines, pH, soluble salts, calcium, and potassium (Table 3). In all cases these factors increase from slope base to ridge top. Since the highest importance of the introduced spe- cies was at the ridge top, as were the above- mentioned factors, the correlations are ex- plainable. However, cause and effect may not necessarily be involved because the role of competition from other species and open habitat availability have not been measured. It is clear that saltgrass grows in a dwarfed and less-dense state at the ridge top (Table 2), and so competition should be reduced and habitat availability for the introduced annual species enhanced. Species diversity for each zone is reported in Table 1. Correlation analysis between spe- cies diversity and perennial forb cover (Table 3) showed that a positive association devel- oped, indicating that patterns of forb distribu- April 1987 Broth ERSON: Plant Com m unity Zonation 331 tion influence diversity in the meadow. Correlation coefficients for each possible pair of independent variables are given in Table 3. All correlations listed are significant (p < 0.05). As shown, there is a high number of significant correlations among factors. A careful review of the data indicates that the majority of the correlations in some way re- flect the gradually changing conditions of en- vironment associated with slope position. When this is understood and we examine the relationships of vegetation to slope position, it is possible to see trends. Annual forbs occupy the more xeric sites along the ridge top where the soils are fine textured and soluble salts and pH are high. The dry-site annuals appear to do well in this zone partly because of the dwarfed and less- dense growth habit of saltgrass. This growth pattern would allow for reduced interspecific competition between the grass and the annu- als. Alternatively, sedges and rushes occupy the wet end of the gradient where the soils are less finely textured and are lower in soluble salts and pH. Underlying springs and seeps keep this end of the gradient moist. The perennial forbs become dominant in Zone 3 at the base of the slope where several of the soil nutrients peak and where soil moisture, solu- ble salts, and pH levels are moderate. Grasses vary widely across the full extent of the gradi- ent, showing peaks in Zones 2 and 4. Correla- tion analysis showed the high levels of grass cover to be positively associated with elevated levels of micronutrients, nitrogen, and sand. The roles of soil salinity, pH, and moisture are not as clearly defined as in other cases (Ungar 1974, Skougard and Brotherson 1979) because of the uniform way they vary in relationship to the slope gradient and to each other. The slope acts as a vehicle wherein the different soil parameters become highly integrated into an environment that varies continuously and thus masks the influence of a single factor on the vegetation patterns. Similar conditions were found in a brackish marsh in Canada where an elevation/salinity/soil texture and soil water content interaction was shown to be responsible for species distribution patterns (Hutchinson 1982). Saltgrass was present in all five zones; few other species extended themselves into multi- ple zones (Table 2). The distribution of the different species along the slope gradient gen- erally approximated the classical bell-shaped curves so reminiscent of Curtis' (1955) vegeta- tional continuum theory. This indicates that the distribution of the species along the slope cannot easily be accounted for by one or two variables, but that competition, soil moisture, soil chemistry and texture, soil minerals, and vertebrate and invertebrate relations all play a role. In this regard the distribution of some species will be primarily related to one factor, while other species distribution will be con- trolled by a different set of factors. However, since there is such a high degree of correlation between the majority of soil factors, the over- all zonation patterns in the vegetation can best be understood when thought of as reflecting the underlying patterns of the abiotic and bi- otic environment. Literature Cited Adams, D A. 1963. Factors influencing vascular plant zonation in N. Carolina salt marshes. Ecology 44: 445-456. Allison. L E 1965. Organic carbon. Pages 1320-1345 in C. A. Black, D. D. Evans, J. L. White. L. E. Ensminger, F. E. Clark, and R. C. Dinaure, No. 9, Part 2, Agronomy Series. Methods of soil analy- sis— chemicals and microbiological properties. Amer. Soc. Agron., Inc., Madison, Wisconsin. Anderson, C. E 1974. A review of structure in several North Carolina salt marsh plants. Pages 307-344 in R. J. Reimold and W. H. Queen, Ecology of halophytes. Academic Press, New York. Arnow, L , B Albee, and a Wyckoff. 1980. Flora of the central Wasatch Front, Utah. 2d ed. University of Utah Printing Service, Salt Lake City. 663 pp. AxELROD. D I 1950. Studies in late Tertiary paleobotany. VI. Evolution of desert vegetation in western North America. Carnegie Inst. Washington Publ. 590; 215-306. Barbour, M G 1970. Is any angiosperm an obligate halophyte? Amer. Midi, Nat. 8(1): 105-120. BouYOUCOS, G. J 1951. A recalibration of the hydrometer method for making mechanical analysis of soils. Agronomy J. 43: 4.34-438. Br.\dy, N C 1974. The nature and properties of soil. 8th ed. MacMillan Publ. Co., New York. Branson, F A , R F Miller, and I. S McQueen 1967. Geographic distribution and factors affecting the distribution of salt desert shrubs in the L'nited States. J. Range Manage. 20: 287-296. Caldwell, M M 1974, Physiology of desert halophytes. Pages .379-390 in R. J. Reimold and w' H. 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A 1966, Salt tolerances of plants growing in saline areas of Kansas and Oklahoma. Ecology 47: 154-155, 1974, Salinity tolerance of inland halophy tic vege- tation of North America, Bull, Soc, Bot, Fr, 120: 217-222. Ungar, I A , W Hogan, M McClelland 1969. Plant communities of saline soils at Lincoln, Nebraska. Amer, Midi, Nat, 82:564-577. VAN derMaarel, E , andJ Leertouwer. 1967. Variation in vegetation and species diversity along a local environmental gradient. Acta Bot, Neerl, 16: 211-221, VoGL, R J 1966, Salt marsh vegetation of upper Newport Bay, California, Ecology 47: 80-87, Waisel, Y 1972, Biology of halophytes. Academic Press, New York, Walsh. G E 1974, Mangroves: a review. Pages 51-174 in R, J. Reimold and W, H. Queen, Ecology of halophytes. Academic Press, New York, Walter, H 1973, Vegetation of the earth in relation to climate and the eco-physiological conditions. The English University Press Ltd,, London, Yake, S , and J D Brotherson 1979, Differentiation of serviceberry habitats in the Wasatch Mountains of Utah, J, Range Manage, 32(4): 379-383, AGE IN RELATIONSHIP TO STEM CIRCUMFERENCE AND STEM DIAMETER IN CLIFFROSE (COWANIA MEXICAN A VAR. STANSBVRIANA) IN CENTRAL UTAH J, D. Brotherson', K. P. Price", and L. O'Rourke' Abstract. — Cliffrose age in relation to stem circnmference and stem diameter was studied in central Utah. Age-circumference and age-diameter predictor equations were developed from material obtained from 10 stands along a65-km section of the Wasatch Mountains foothills. Ages estimated on material of known age by the two ecjuations were highly similar. Age predictions were more accurate for young stems than for older stems. The oldest stem aged was 163 years. Population biology seeks to understand and interpret variations in the numbers of organ- isms as they are distributed in time and space. Among the populations of a given species, differences in size of individuals, density, age structure, and morphological characters often reflect underlying variations in the genetics of those populations as well as the way in which they interact, survive, and reproduce m their individual environments. Successful repro- duction in a species over ecological and evolu- tionary time and across a range of environ- ments, combined with the development of wide variation in the attributes of its individ- ual populations, is of interest. Measurement of population size, density, age structure, and morphological variation is enhanced when a reliable tool for aging the individuals of a pop- ulation can be employed. Studies of growth-ring variation in tree populations have been used extensively for dating (Douglas 1935, Clock 1937), recon- struction of past climates (Fruits 1971, Harper 1979), interpretation of successional dynamics (Burkhardt and Tisdale 1969, Barney 1972), and assessment of differences in the environ- ments of selected habitats (Ferguson and Humphrey 1959, Fritts 1962, Stockton and Fritts 1973). Although trees have been the primary focus of such studies, papers dealing with habitat variations and age-prediction models for shrubs are available (Ferguson 1958, Ferguson and Humphrey 1959, Broth- erson et al. 1980, Brotherson et al. 1984). Studies dealing with circumference-age rela- tionships of shrubs and their value in the de- velopment of age-prediction models, inter- pretations of habitat factor differences, and successional dynamics are less known. Many western shrub species show asymmetrical stem growth; this suggests the need to under- stand the relationship between stem circum- ference and age for studies in population dy- namics. This study considers stem diameter and stem circumference-age relationships of cliffrose {Cowania mexicana var. stansburi- ana) from sites in central Utah. Study Area The study area is located along the gravelly shores of prehistoric Lake Bonneville on the west face of the Wasatch Mountains, Utah County, Utah, between American Fork Canyon on the north and Santaquin Canyon on the south, a distance of 65 km. Elevation varied little across the sites, averaging 1,562 m. Aspect varied between 140 and 330 de- grees on a standard compass bearing. The cliffrose populations selected for study were chosen from the largest and most dense stands in the area. Soils, which varied from gravelly sandy loams to gravelly clay loams, were heav- ily skeletal (Price and Brotherson 1987), slightly basic (pH = 7.7), and very low in soluble salts. Soil mineral nutrient concentra- tions were also verv low (Price and Brotherson 1987). The Wasatch Mountains are primarily com- posed of sedimentary limestone formations 'Department of Botany and Range Science. Brigham Young University. Prove. Utah 84602. -Department of History and Geography. Utah State University, Logan, Utah 84322-0710. 334 April 1987 Brotherson etal.: Utah Cliffrose 335 Table 1 . Predictor equations for cliffrose age along with deviations of estimated age from true age for stems of known material. Estimator factor Prediction equation r^ Sig. level Deviation of estimated age from true age X SD CV Diameter Circumference y ' y = = 6.801 + 14.209.x = 5.450 + 4. 728x 0.69 0.73 0.001 0.001 5.8 6.1 4.8 1.2 5.1 1.2 90 -| / 80- / 70- / < UJ > • . / UJ g 50- . / ' C/5 o tr LL U- • / ' 30- • • / /..-. J = 6 80 +14 21 X r = 83 r^ = 69 20- r' ' sig = 001 10- 1 CLIFFROSE DIAMETER (INCHES) Fig. 1. The relationship between stem diameter and stem age in cliffrose in central Utah. high in calcium carbonate. Rainfall in the area averages 422 mm (NOAA 1922-72), with ap- proximately 280 mm falling between October and April (USDA 1972). The average annual temperature is 10.6 C, with a frost-free period averaging 150 days. Cliffrose, rubber rabbitbrush {ChrxjHO- thamnus nauseosus), and Arterinsia triden- tata dominated the site overstory. The under- story was dominated by annuals of which cheatgrass (Bromus tectorum), madwort {Alysswn alyssoides), Japanese brome {Bro- mus japonicus), tumblemustard {Sisymbrium altissimum), and cutleaf filaree {Erodium ci- cutarium) were the most important. The perennial bluebunch wheatgrass {Agropyron spicatum) was also important in the under- story (Price and Brotherson 1987). Methods Ten study sites, each 10 x 10 m (0.01 ha), were selected from the above communities. Five stems, each from randomly selected in- dividuals, were obtained from the 10 sites for a total of 50 stems. Stems were sectioned diag- onally, polished with fine sandpaper, and the annual growth rings counted twice (indepen- dently) at the widest part of the stem with the aid of a stereoscopic microscope (Ferguson 1970, Brotherson et al. 1980). One ring was assumed to equal one year of growth. Stem diameters and circumferences were mea- sured with a diameter tape. Linear regressions of age on diameter and age on circumference generated stem diame- ter-age and stem circumference-age predic- tor equations (Brotherson et al. 1980). The predictor equations were then checked by es- timating the stems of known age. The predic- tor equations were also used to predict mean ages of the 10 populations. Results and Discussion Cliffrose in central Utah generally grows on escarpments with southwest exposures hav- ing greater than 40% slope. The populations studied in this report were located along what had once been the gravelly shoreline of old Lake Bonneville. Adjacent, finer-textured soils that accumulated on the bottom of the lake apparently create a barrier to the species, confining it to the better-drained, lighter- textured soils of the ancient beach. The sites are typically exposed to environmental severi- ties and are subject to wide variations in envi- ronmental extremes. Successful inhabitants of these sites must withstand a broad range of environmental fluctuations. Often such envi- 336 Great Basin Naturalist Vol. 47, No. 2 5 45 + 4 73 : CLIFFROSE CIRCUMFERENCE (INCHESl Fig. 2. The relationship l>etween stem circumference and stem age in cUffrose in central Utah. ronmental variation is evidenced in differen- tial growth rates, varying plant heights, and morphology of individuals of separate popula- tions. Such was the case with respect to our 10 populations. For example, average length of annual twig growth varied across these popu- lations from a low of 2.0 cm to a high of 13.3 cm, indicating variable growth rates between the different populations. Cliffrose stem diameters ranged from 0.5 inches to 4.8 inches, and the circumferences varied from 2.44 inches to 15.06 inches. Lin- ear regression was used to establish age- diameter (r" = 0.69) and age-circumference (r" = 0.73) predictor equations (Table 1, Figs. 1 and 2). Both equations were significant at the 0.001 level. The slightly better fit of the cir- cumference equation is due to the irregular growth patterns of the cliffrose stems. This irregular growth form (asymmetrical) made it very difficult to measure the stem diameters, especially under field conditions. The diame- ters were measured at the widest part of the stem. When the two predictor equations were used to estimate stem ages from original mate- rial (stems used to generate the equations). the estimated ages showed no significant dif- ference (Table 1). The diameter-age predictor equation estimated the ages more accurately than did the circumference-age predictor equation. However, there were no significant differences between true age and estimated age. Stem diameter and stem circumference were plotted against one another (Fig. 3). The relationship is significant (p < 0.001; r" = 0.98), indicating that either diameter or cir- cumference may be used to determine the age of cliffrose in this area. However, circumfer- ence measurements may be more accurately obtained in the field because of the irregular growth patterns of the cliffrose stems. Results indicate that the predictor equa- tions are more accurate for young stem age than for older stem age (Fig. 4). When the deviation of predicted age from true age is plotted against true age, the difference in- creases as cliffrose stems get older. Similarly, as the stems of mountain mahogany {Cerco- carpus) get older, they grow slower and show smaller widths in their growth rings (Brother- son et al. 1980). Basal circumference measurements were taken on 30 randomly selected individuals per April 1987 Brotherson etal.: Utah Cliffrose 337 CO y = 24 +3 04 X r = 9901 r^ = 9802 sig = 001 CLIFFROSE DIAMETER (INCHES) Fig. 3. The relationship between stem diameter and stem circumference in chfFrose in central Utah. site for 9 of the 10 sites. One site had only 18 living individuals. From these basal measure- ments (288 individuals), the plants of each stand were aged. The youngest individual found was 11 years old and the oldest 163 years. When the ages for all individuals of a en ^ nr UJ < LU co > UJ ' — ' CO LU o o nr < LL n LL III _l ►- U o II Q o LU CC a. LU u. O _l < 7' Z) o 1- o s < > ^ LU <) Q CC 20-, 15- 10- 5- <^ ^ ^ ^ <^ JP ^ ^ c? .^^ ^ V > CLIFFROSE AGE (IN CLASSES OF 5 YEARS) Fig. 4. The relationship of the difference between pre- dicted age and true age in cliffrose in central Utah. specific site were averaged, the youngest pop- ulation was 28 years and the oldest 69 years. Average community age was found to be nega- tively correlated with cliffrose density (p < 0.05) and positively with a hedging index (p < 0.001), indicating that the longer the popula- tion has been established, the taller and less dense the individuals become. This, we feel, is due to the impact of wildlife (specifically mule deer) on cliffrose plants, since they are preferred forage for these animals. Literature Cited Barney, M A 1972. Vegetation changes following fire in the pinyon-juniper type of west central Utah. Un- published thesis, Brigham Young University, Provo, Utah. Brotherson. J D.J N D.\vis,.^ndL Greenwood 1980. Diameter-age relationships of two species of mountain mahogany. J. Range Manage. 33: 367- 370. Brotherson. J D.J. G. Carman, and L A Szyska 1984. Stem-diameter age relationships oiTamarix ramo- sissima in central Utah. J. Range Manage. 37: 362-364. Brotherson, J D . S R Rushforth.VV E Evenson. J R. JoHANSEN. and C. Morden 1983. Population dy- namics and age relationships of eight tree species in Navajo National Monument, Arizona. J. Range Manage. 36: 250-256. 338 Great Basin Naturalist Vol. 47, No. 2 BURKHARDT, J W . AND E W TiSDALK 1969. Nature and successional status of western juniper vegetation in Idaho. J. Range Manage. 22: 264-270. DouGLA.S, A E 1935. Climatic cycles and tree growth. In: A study of the annual rings of trees in relation to climate and solar activity. Carnegie Institute Washington, Publ. No. 289, Vol. 1, Washington. Ferguson. C W 19.58. Growth rings in big sagebrush as a possible aid in dating archaeological sites. Pages 210-211 in A. E. Dittert, Jr., ed.. Recent devel- opments in Navajo Project salvage archaeology. El Palacio. 65:201-211. Ferguson. C W , and R R Humphrey 19.59. Growth rings on big sagebrush reveal rain records. Prog. Agr. in Arizona 11: 3. Fritts, H C 1962. The relation of growth ring widths in American beech and white oak to variations in climate. Tree-ring Bull. 25: 2-10. Clock, W S 1937. Principles and methods of tree-ring analysis. Carnegie Institute Washington, Publ. No. 486, Washington. 100 pp. Harper. K T 1979. Dendrochronology-dating with tree rings. In: W. M. Hess and R. T. Matheny, eds.. Science and religion: toward a more useful dia- logue. Vol. 1. Paladin House Publishers, Geneva, Illinois. NOAA 1922-72. Annual climatic summaries for Utah (Provo Station). Data and Information Service, National Climatic Center, Asheville, North Caro- lina. Climatological Data. Vols. .34-74 (No. 13). Price, K P , and J D Brotherson 1987. Habitat and community relationships of cliffrose {Cowania nu'xicana var. stansburiana) in central Utah. Great Basin Nat. 47(1): 132-151. Stockton. C W . and H C Fritts 1973. Long-term reconstruction of water level changes for Lake Athabaska by analysis of tree rings. Water Res. Bull. 9: 1006-1027. USDA 1972. Soil survey of Utah County, Utah. USDA, Soil Conservation Service. U.S. Government Printing Office, Washington, D.C. 161pp. DEMOGRAPHY OF BLACK-TAILED PRAIRIE DOG POPULATIONS REOCCUPYING SITES TREATED WITH RODENTICIDE R. P. CiiKotta' \ D. VV, Uresk\ and R. M. Hansen' Abstract — A rodenticide, zinc phosphide, was apphed to remove black-tailed prairie dogs (Cynomijs ludovicianus) from 6 ha of a prairie dog colony in southwestern South Dakota. Another adjacent 6 ha was left untreated. The removal experiment was repeated two consecutive years. Contingency table analysis showed that the resultant population was not homogeneous; age classes by se.x of the immigrant and resident subpopulations were different (P < 0.01). The ratio of adidt females to yearling females was greater among immigrants than among residents (P < 0.03). Female immigrants did not produce young in the treated zone during the year of their arrival. Fewer of these females displayed distended nipples than expected (P < 0.01), indicating that these immigrants did not reproduce during the reproduc- tive season immediately preceding dispersal and suggesting that failure to reproduce may have stimulated dispersal. The black-tailed prairie dog {Cijnomys lu- dovicianus) is a herbivorous, social ground squirrel that is native to the Great Plains of North America. Black-tailed prairie dogs live in colonies known as prairie dog towns. Within these colonies, prairie dogs dig bur- rows and alter the composition of the vegeta- tion (Koford 1958, Coppocketal. 1983). Large populations of black-tailed prairie dogs presently exist within the boundaries of Bad- lands National Park, South Dakota. During the 10 years prior to this study, prairie dog towns had expanded in the park and on other federal, state, and private range- land and farmland (Schenbeck 1982). Man- agers of parks and refuges sought to reduce the black-tailed prairie dog populations by applying rodenticides to diminish conflicts with rangeland users beyond their boundaries. However, this practice has not always been cost-effective (Collins et al. 1984). The rapid invasion of treated colonies by other immigrating prairie dogs is a major cause of failure of prairie dog control. If a source of immigrants is present, black-tailed prairie dogs can regain their initial population numbers within 1 to 3 years following the application of rodenticide to the town (Knowles 1985). Elimination of immigrant in- dividuals that take up residence in vacant bur- rows of the treated colony must be accom- plished before control programs can be successful. Information is needed that can identify the origin, demography, and behav- ior of prairie dogs that reinhabit a colony after application of rodenticides. Our study focused on the demography of immigrant populations of black-tailed prairie dogs that formed after rodenticide treatment of the original popula- tion. The objective in this study was to deter- mine differences in sex and age-class distribu- tions between resident and immigrant populations. Study Area and Methods The study was conducted during three summer field seasons from 1981 to 1983 on a colony northwest of the edge of the Robert's prairie dog town in Badlands National Park, southwestern South Dakota. The area re- ceived approximately 40 cm of precipitation annually, most of which fell between early April and mid-July during intense, patchy thunderstorms. The mean temperature was 10 C, ranging from — 5 C in Januarv to 26 C in July. Soils in the study area were deep, sandy- loam sediments interspersed with thin layers of sand and gravel from former stream beds. Topography of the area was gently rolling, mixed-grass prairie. Dominant plant species were western wheatgrass {Agropyron smithii), buffalograss {Buchloe dactyloides), needle-and-thread grass (Stipa coinata), blue grama (Bouteloua gracilis), Patagonia Indian- Range Science Department. Colorado State University, Fort Collins, Colorado 8052.3. "Present address: Department of Anthropology. State University of New York at Binghamton. Binghamton, New York 13901 USDA-Forest Service, Rocky Mountain Forest and Range Experiment Station, Rapid City. South Dakota 57701 339 340 Great Basin Naturalist Vol. 47, No. 2 wheat {Plantago patagonica), and prostrate vervain (Verbena hracteata). A 12-ha segment of the colony that bor- dered uncolonized grassland was used. The northern 6 ha of the site was chosen for roden- ticide treatment; the remaining 6 ha was left untreated. Since black-tailed prairie dogs are highly territorial, rarely leaving the boundaries of their territories to forage (King 1955), the treated and untreated zones were purposefully set out adjacently to determine if individuals from the untreated half would abandon their territories to occupy the nearby vacant burrows or expand their territories into the treated side of the colony. We trapped the population on this site before beginning treat- ment to determine the original demography of the resident colony and to test for hetero- geneity of the population due only to the loca- tion of the zones proposed to be treated or left untreated. Rodenticide (2% zinc phosphide coated grain) was applied to the treated 6 ha after pretreatment grain was applied accord- ing to published recommendations (Tietjan 1976). Rodenticide was placed on all burrow mounds during the last week of August 1981 and 1982. The control site was left untreated. Thus, population samples of prairie dogs in the treated zone in both 1982 and 1983 were newly arrived immigrants, while a continuous population of residents was concurrently monitored in the untreated zone. All prairie dogs were trapped and marked during the first week in June and third week in August 1982 and 1983. We trapped in two sessions to avoid missing individuals that were difficult to trap or had not yet immigrated. Prairie dogs were trapped using 52 Tomahawk 32-inch live-traps (no. 206) baited with com- mercial sweet chop, a molasses-coated mix- ture of cracked corn, rolled barley, and rolled oats. All animals were toe-clipped for identifi- cation and then released. Prairie dogs were classed as adults (> 1 yr), yearlings, or juve- niles, based upon their condition, size, weight, and previous record of capture. We addressed differences between immi- grants and residents with the null hypothesis that the resulting population was demograph- ically undisturbed by treatment and immigra- tion; we expected the popvdation to be homo- geneous. Observed sex ratios, the distri- bution of age classes by sex, and adult to year- ling ratios by sex of the newly arrived immi- grant subpopulation were tested against the distribution of the untreated, continuously growing subpopulation in contingency tables with fixed-row and column values. Expected cell frequencies were generated and assumed to be the expected discrete distribution for test of population homogeneity using the chi- square statistic (a = 0.05). An analysis was performed separately for 1982 and 1983 ob- served populations. The chi-square statistic was used, as well, to determine significance of a posteriori differences observed between the immigrants and residents. Though an intensive effort was mounted to trap all individuals by selectively situating traps, it became obvious that some animals were not captured. We assumed that this un- trapped portion of the population was small and not confined to any particular age class or sex. We also assumed that marking and trap- ping of the animals did not influence their dispersal behavior. Results and Discussion Before zinc phosphide was applied, a total of 76 individuals were captured during sum- mer 1981 (Table 1) in the zone reserved for future rodenticide treatment. Only 55 prairie dogs were captured during the same period in the adjacent part of the colony, which would remain untreated. This population was statis- tically homogeneous, though there were noteworthy differences between the spatially segregated subpopulations that were not statistically significant at the chosen alpha- level. The population sex ratio in the future treated zone was 1.30:1, and that observed in the future untreated zone was 0.72:1 (X" = 2.78, 1 d.f., P = 0.10). The juvenile sex ratio (male:female) in the future treated zone was 1.63:1, and that observed in the future un- treated zone was 0.82:1 (X" = 2.59, 1 d.f., P = 0.11). The pretreatment age classes by sex distributions for the zonal subpopulations were not statistically different (X" = 4.00, 5 d.f., P = 0.54), although the number of ani- mals on the treatment site was substantially greater than on the untreated. Application of zinc phosphide in 1981 eliminated 98.7% of the marked prairie dogs in the treatment site and 100% in 1982. The distribution of animals into categories by age class and sex (Table 2) showed the April 1987 Cincotta et al. : Prairie Dog Table 1. Age-class distribution by sex of pretreatmeiit black-tailed prairie dog subpopulatioiis. 341 Pretreatment populations (1981); Future treated zone Futui re untreated zone Age class Males Females Total Males Females Total Adults 9 11 20 4 8 12 Yearlings 3 3 6 1 2 3 Juveniles 31 19 50 IS 99 40 43 33 76 23 32 55 Table 2. Age-class distribution by sex of posttreatment black-tailed prairie dog subpopulations. Posttreatment populations (June- -August 1982 and 1983); Immigrants Residents Age class Males Females Total Males Females Total 1982: Adults 5 2 7 6 11 17 Yearlings 8 11 19 3 4 7 Juveniles 0 0 0 20 15 35 13 13 26 29 30 59 1983; Adults 3 2 5 5 13 18 Yearlings 8 6 14 3 5 8 Juveniles 0 0 0 99 20 42 11 8 19 30 38 68 resultant population was not homogeneous during either posttreatment vear (1982: X~ =^ 40.09, 5 d.f., P < 0.01; 1983: X' = 37.10, 5 d.f. , P < 0.01). There were more yearling females and yearling males than e.xpected on treated sites. Garrett and Franklin (1982) re- ported a high percentage of yearling males (91%) in the male intercolony immigrant pop- ulation in Wind Cave National Park, South Dakota. However, their study of intercolony dispersal showed that 57% of the female prairie dogs captured were adults (Garrett and Franklin identified two-year-olds, and > two-year-olds), which differed strongly from our findings; onlv 15% were adults during 1982, 25% during 1983. It should be noted that, while Garrett and Franklin studied only long-distance intercolony dispersal of black- tailed prairie dogs, both intracolony immigra- tion and short-distance intercolony dispersal were possible from two nearby colonies (Robert's and Hocking's dog towns). Of 64 immigrants captured in two years, only 5 pre- viously marked immigrants (3 males, 2 fe- males) were caught; 4 came from the adjacent untreated site (2 males, 2 females), and 1 male arrived from Hocking's dog town, less than 1 km from the edge of the study colony. There was no observed reproductive suc- cess during either 1982 or 1983 among the newly established populations of prairie dogs on the treated site. This suggests that female black-tailed prairie dogs disperse after the mating season and do not bear young during their first year in a newly established terri- tory. If this observation can be generalized to other populations, reports of females with ju- veniles directly following a control effort clearly indicate a failure to eliminate animals rather than the immigration of other prairie dogs. Nonlactating females accounted for a greater proportion of the immigrant female subpopulation than e.xpected (1982: X" = 18.16, 1 d.f, P < 0.01; 1983: X^ =- 12.86, 1 d.f. , P < 0.01). Nonlactating females made up 100% (13/13) of the female immigrants in 1982 and 75% (6/8) in 1983. Nonlactating females on the control site made up only 11% (1/9) of the potentially reproductive population in 1982 and were not observed (0/12) in 1983. Because the majority of black-tailed prairie dogs in South Dakota are known to disperse between May and the early part of July (Gar- rett and Franklin 1982), well after their breed- ing season, dispersal in these individuals may 342 Great Basin Naturalist Vol. 47, No. 2 Table 3. Demographic ratios of prairie clogs during repeated trials on a colony where one side of the colony was treated with rodenticide (2% zinc phosphide) and a similar-sized zone was untreated. Prairie dogs in treated zones were first-year immigrants in both trials. Ratios were considered different at the P < 0.05 (2x2 contingency table, X^, 1 d.f ). ::1) 1982 1983 Demographic ratios (x Immigrant Resident P Immigrant Resident P Population se.x ratio 1.00 0.97 0.94 1.38 0.79 0.29 Adult sex ratio 2.50 0.55 0.11^ 1.50 0..38 0.18^ Yearling sex ratio 0.73 0.75 0.97 1.33 0.60 0.,38 Juvenile sex ratio B 1..33 B B 1.10 B Adult males: yearling males 0.63 2.00 0. 19^ 0..38 1.70 0.12^ Adult females: yearlin g females 0.18 2.75 <0.01 0.33 2.60 0.02 Non-significant P-value may be result of small - No juveniles captured in treated site have been stimulated by their failure to repro- duce. King (1955) reported that females immi- grated after weaning juveniles, leaving terri- tories to their young. This may be the case for some females, especially older individuals that are among populations of dispersers. However, Hoogland (1985) has demonstrated that the success of reproductive efforts of fe- male prairie dogs may ultimately hinge upon defending nestling offspring from infanticidal females within the territory. Two yearling females, captured within 25 m of each other as juveniles during August 1981 within the untreated zone, were recaptured as immigrants to the treated zone in June 1982. Both traveled over 400 m to their newly acquired territories. Both females showed no signs of having lactated during that season. By August 1982 one female had returned to her untreated natal territory. A similar instance of a returning immigrant was observed by Gar- rett (1982). In our study this same female again immigrated into the treated area in 1983. At the time of her second immigration, she showed signs of previous lactation. Immigrants formed a transient subpopula- tion. In 1982 only 54% (14/26) of the immi- grants were captured during both trapping sessions, compared to 73% (43/59) of the resi- dents (X' = 2.96, 1 d.f , P = 0.09). Again in 1983 fewer immigrants, 47% (9/19), were cap- tured in both sessions than were untreated animals, 68% (46/68), though the immigrant distribution was not significantly different from the expected (X" = 2.63, 1 d.f., P = 0.11). King (1955) also reported that during colony expansion newly established territo- ries were occupied by highly unstable popula- tions where many different adults were trapped over a short period of time. The study adds to the evidence that marked demographic differences exist between resi- dent, undisturbed black-tailed prairie dog populations and those of immigrants. We ob- served that nonreproductive females com- prised a large proportion of the female immi- grants each year. During our study female immigrants did not produce young in their new territories during the year in which they dispersed. Also, immigrants who seem to have settled into burrows are likely to "disap- pear" at a greater rate than expected. Glearly, the complexity in the nature of prairie dog dispersal is just one more factor that indicates the need for careful, intensive management of colonies in parks, refuges, and on grazed pub- lic land. Acknowledgments This study was sponsored by a research grant from the National Park Service (Con- tract No. CX1200-1-B035) and logistic sup- port from the U.S. Forest Service Forest and Range Experiment Station at Rapid City, South Dakota. We wish to thank Superinten- dent Gil Blinn, Chief Ranger Lloyd Kortje, District Ranger Mike Glass, and the rest of the staff of Badlands National Park for their assistance during the study. We also thank the U.S. Forest Service technical staff for their assistance. Dale Madison and Mike Little were kind enough to lend their comments on technical aspects and style. Literature Cited COLLIN.S, A R , J P Workman, and D W Uresk. 1984. An economic analysis of black-tailed prairie dog (Ci/nomiis ludovicianus) control. J. Range Man- age. 37: 358-361. April 1987 CiNCOTTA ETAL.: PRAIRIE DOG 343 CoppocK, D L J K DetlingJ E Ellis, and M I Dykr 1983. Plant-herbivore interactions in a North American mixed-grass prairie. I. Effects of black- tailed prairie dogs on intraseasonal aboveground plant biomass and nutrient dynamics and plant species diversity. Oecologia (Berl.)56: 1-9. Garrett, M G 1982. Prairie dog dispersal in Wind Cave National Park. Unpublished thesis, Iowa State University, Ames. Garrett, M G., andW L Franklin 1982. Prairie dog dispersal in Wind Cave National Park: possibilities for control. Pages 185-198 in R. M. Tinini and R. J. Johnson, eds., Proceedings: fifth Great Plains wildlife damage control workshop. University of Nebraska, Lincoln. Hoogland. J L 1985. Infanticide in prairie dogs: lactat- ing females kill offspring of close kin. Science 230: 1037- 1040. King, J A 1955. Social behavior, social organization, and population dynamics in a black-tailed prairie dog town in the Black Hills of South Dakota. Contribu- tions from the Lab. of Vert. Biol., No. 67. Univer- sity of Michigan, Ann Arbor. Knowles, C J 1985. Population recovery of black-tailed prairie dogs following control with zinc phos- phide. J. Range Manage. 39(3): 249-251. KoFORD, C. B 1958. Prairie dogs, whitefaces, and blue grama. Wildl. Monogr. No. 3. SCHENBECK, G L 1982. Management of black-tailed prairie dogs on the national grasslands. Pages 207-213 in R. M. Timm and R. J. Johnson, eds., Proceedings: fifth Great Plains wildlife damage control workshop. University of Nebraska, Lin- coln. TiETjAN, H P 1976. Zinc phosphide: its development as a control agent for black-tailed prairie dogs. U.S. Dept. of the Interior, Fish and Wildl. Service Special Scientific Report, Wildl. No. 195. Wash- ington, D.C. WESTERN PAINTED TURTLE IN GRANT COUNTY, OREGON Jeffrey H. Black' and Andrew H, Black" AbstracT. — ^The western painted turtle, Chrijsemijs picta belli (Gray), is recorded for the first time from Grant County, Oregon. This specimen represents the southwesternmost occurrence of the species in Oregon. On 27 August 1984 a western painted tur- tle, Chnjsemys picta belli (Gray), was col- lected in a small pond near Canyon City, Grant County, Oregon. This specimen repre- sents the first record of this turtle in Grant County and the southwesternmost occur- rence of this species in the state (Nussbaum, Brodie, and Storm 1983). The turtle was observed swimming quietly on the surface of a one-acre pond filled with aquatic vegetation. The pond was on a sage- brush- and juniper-covered hillside adjacent to Canyon Creek on the west side of Canyon City. The pond is 1 km west of Canyon Creek and 6 km from the John Day River and mouth of Canyon Creek. Later the turtle was cap- tured, sexed, measured, photographed, and released back into the pond. The turtle was an adult female with a cara- pace length of 172.3 mm and width of 132.3 mm. Its plastron length was 164.5 mm and width 89.2 mm. She was heavy and appeared healthy. Nussbaum, Brodie, and Storm (1983) report females range from 95 to 210 mm in carapace length in the Willamette Valley of western Oregon. Black and Storm (1970) reported a north- western pond turtle, Clemmys mannorata marmorata (Baird and Girard), from Grant County and noted the sightings of other tur- tles in ponds bordering the John Day River in Grant County. Northwestern pond turtles and western painted turtles have probably moved from the Columbia River southwest- ward in the John Day River to Grant County. There are records of western painted turtles in Umatilla, Morrow, and Union counties, all north of Grant County but south of the Co- lumbia River in eastern Oregon. The possibil- ity also exists that the turtle was captured elsewhere or purchased as a pet and then released into the pond or area where it was captured. Literature Cited Black. J H , and R M Storm 1970. Notes on the her- petologv of Grant Countv, Oregon. Great Basin Nat, 30(1): 9-12. Nussbaum. R A , E D Brodie. Jr , and R M Storm. 198.3. Aniphiliians and reptiles of the Pacific Northwest. University Press of Idaho, Moscow. 332 pp. 'Department of Biology, Oklahoma Baptist University, Shawnee, Oklahoma 74801 ^4003 Blame Road, Shawnee, Oklahoma 74801. 344 AMERICAN SWALLOW BUG, OECIACUS VICARIUS HORVATH (HEMIPTERA: CIMICIDAE), IN HIRUNDO RUSTICA AND PETROCHELIDON PYRRHONOTA NESTS IN WEST CENTRAL COLORADO Thomas Orr' and Gary McCallister' Abstract — Oeciacus vicarius bed hugs were collected i'rom 32% ot'Hirundo ni.stica nests and 83% ofPetroclielidon pyrrhonota nests on bridges in western Colorado in December 1984. A total of 409 bugs (158 adults and 251 juveniles) were counted in 47 nests, two months after the hosts had departed for the winter. Two regular avian visitors to the Colorado River system in west central Colorado are the cliff swallow, Petrochelidon pyrrhonota, and the barn swallow, Hirundo rustica. They spend the warm late spring to autumn months in North America and winter in South Amer- ica (Knopf 1977). The cliff swallow builds a gourd-shaped mud nest lined with grass and feathers beneath bridges and on natural cliff faces. The barn swallow builds an open nest with mud pellets and lined with feathers and straw under bridges or on buildings. Oeciacus vicarius Horvath, the American swallow bug, has been previously reported from Petrochelidon (Meyers 1928) at Dolores, Colorado (Gillette and Baker 1895). Usinger (1966) lists Hirundo as a rare host, but some controversy seems to e.xist over host specificity. The previous report of O. vicarius in Colorado was from the inhabited nests in the spring of the year. In this paper we report on the incidence of O. vicarius in both barn swallow and cliff swal- low nests during December in west central Colorado, a new geographic area. Materials and Methods In December 1984, 41 barn swallow nests and 6 cliff swallow nests were collected from beneath highway bridges west of Fruita, Col- orado. They were placed into plastic bags, numbered, and sealed. Six nests at a time were weighed and then processed under Berlese funnels for six to eight hours. Visual examination and additional manual extraction of the bugs followed. Specimens were col- lected into 70% ethanol. Mites, ticks, spiders, moths, and dermestids were included, but the most abundant species was Oeciacus vi- carius. These were identified under magnification (lOX to 400X) using Slater and Baranowski's (1978) key to the true bugs. The immature stages were identified (I, II, III, IV, V) with a key in Usinger (1966). Some specimens were mounted using standard techniques in balsam on glass slides; others were mounted and cleared in lactophenol for photographs. A total of 409 Oeciacus vicarius specimens was collected. Of 158 adults, 99 were male, 59 female. There were 39 stage I, 44 stage II, 49 stage III, 85 stage IV, and 24 stage V instars, a total of 251 immatures. Table I shows the composition of the population in each kind of nest. Two hundred forty-eight bugs were in 13 of the 41 barn swallow nests, a prevalence of 32%. This is a mean of 19 bugs per infested nest; numbers ranged from 1 to 68 per nest. One hundred sixty-one bugs were in 5 of the 6 cliff swallow nests (prevalence = 83%), a mean of 32 bugs per infested nest, with num- bers ranging from 2 to 103 per nest. It should be noted that the P. pyrrhonota nests are much bulkier (x = 451 g/nest) than the H. rustica nests (x = 199 g/nest). This means that there was 1 bug per an average of 96 gm of Hirundo nest and 1 bug per 70 gm of Petrochelidon nest. Discussion The doubling of the spermalege in Oeciacus 'Department of Biological Sciences. Mesa College, Grand Junction. Colorado 81502 345 346 Great Basin Naturalist Vol. 47, No. 2 Table I. Oeciacus vicarius population in H. rustica and P. pyrrhonota nests in December 1984. Host nest Adults Instar stages M F Total I II III IV V Total H. rustica P. pyrrhonota 67 32 46 13 113 45 27 12 16 28 27 50 32 35 15 9 135 116 vicarius was noted by Cragg (1920) and Abra- ham (1934). Ludwig and Zwanzig (1937) re- ported it in 0.5 to 40% of the females in the populations they studied. In the present case it occurred in 1.7% of the females. The red body color seen in some stage V instar nymphs is not mentioned in the litera- ture, although Spencer (1930) describes a white specimen. This anomaly of red body occurred in 4.2% of the stage V instars. Meyers (1928) names Petrochelidoti hi- nifrons as a host but dismisses Hiriindo enj- throgaster. Usinger (1966) lists P. olbifrons and, more rarely, H. enjthro faster. This study demonstrates this parasite in the winter nests of two additional hosts: P. pyrrhonota and H. rustica. It tends to support the claim that the barn swallow may be a less common host. It also establishes the geographic distri- bution of the parasite in a previously unre- ported area. Literature Cited Abraham, R 1934. Das verhalten der Spermien in der weiblichen Bettwanze (Cimes Icctualarius) und der Verbleib der Uberschussigen Spermasse. Z. Parasitenk. 6: 559-591. Quoted in R. L. Usinger, 1966, Monograph of Cimicidae (Hemiptera-Het- eroptera). Ent. Soc. of America, College Park, Maryland. Cragg, F W 1920. Further observations on the repro- ductive system ofCimex with special relerence to the behavior of the spermatozoa. Indian J. Med. Res. 8: 32-79. Gillette, C P , andC F Baker 1895. A preliminary list of Hemiptera of Colorado. Colorado Agric. Expt. Sta., Bull. 31 (No. I, Tech. Ser.). Knopf, A 1977. The Audubon Society field guide to North American birds, western region. Pages 778-779 in Chanticlear Press Edition, New York. Ludwig, VV , and H Zwanzig. 1937. Ueber normalen und abnormalen (inversen, derdoppelten, ster- ilen, intersexuellen) Kopulationsapparat der Bett- wanze. Z. Natui-w. 89: 136-148. Quoted in R. L. Usinger, 1966, Monograph of Cimicidae (Hemiptera-Heteroptera). Ent. Soc. of America, College Park, Maryland. Meyers, L E 1928. The American swallow bug, Oecia- cus vicarius Horvath (Hemiptera, Cimicidae). Parasitology 20(2); 159-172. Slater, J M, AND R M Baranowski 1978. How to know the true bugs (Hemiptera-Heteroptera). Wm. C. Brown Co. Publ., Dubuque, Iowa. 256 pp. Spencer. G J 1930. The status of the barn swallow bug, Oeciacus vicarius Horvath. Canadian Entomol. 62(1): 20-21. Usinger, R L 1966. Monograph of Cimicidae (Hemiptera-Heteroptera). Ent. Soc. of America, College Park, Maryland. PSEUDOCROSSIDIUM AUREUM (BARTR.) ZAND. (POTTIACEAE, MUSCI) NEW TO UTAH John R. Spence' Abstract — Fseuducrossidium aurcum (Bartr. ) Zand. (Pottiaceae, Musci) is reported as new to Utah from a locaHty in Wayne County. The species distribution is noted and comparisons are made with the other three species of Pseudocrossidiiim found in North America. Despite excellent recent floras for Utah (Flowers 1961, 1973), the bryophyte flora of the state remains incompletely known. This is even more obvious for the intermountain re- gion (sensu Cronquist et al. 1972). Recent studies that have concentrated on dryland bryophyte floras (e.g., Magill 1976, Stark and Castetter 1982, Mcintosh 1986) emphasize the diversity of dryland bryophytes. The stud- ies of Magill and Mcintosh in particular, which concentrated on intensive collecting in small regions, indicate that many elusive and poorly known bryophytes remain to be dis- covered in the western drylands. While conducting studies on the bryophyte flora of southern Utah, I collected a species of Didymodon, which proved upon identifica- tion to be D. vinealis (Brid.) Zand. Intermixed with the Didymodon were a few small sterile plants that keyed to Pseudocrossidiiim oii- reum (Bartr.) Zand, using the key in Zander (1979). A duplicate of the collection was con- firmed by Dr. Zander of the Buffalo Museum of Science. This species was not previously known from Utah, and the nearest known populations are in southern Coconino County in Arizona (Haring 1961). The site information and associated species for this collection were: Utah: Wayne Co., Capitol Reef National Park, near the Rim Overlook. Growing intermixed with Didymodon vinealis at base of cliff of Navajo Sandstone in shaded, north-facing alcove on dry sand. In slickrock and pinyon- juniper communities, with Pinus edtdis. Jiinipenis os- teospenna, Shepherdia canadensis, Coleo^ijne ramosis- sirna. Bouteloua gracilis. Yucca ssp., and Opuntia ssp. Elevation 2,19.5 m, 26 November 1986, Spence .3.319a. pH of sand = 6.0 (pHydrion paper). Deposited in BUF and my personal herbarium. Pseudocrossidiiim aiireiim was originally described from the Santa Catalina Mountains of southern Arizona as Tortula aiirea (Bartram 1924). The transfer to Pseudocrossidiiim was made by Zander (1979). An important compo- nent of the bryophyte stratum in the Sonoran and Chihuahuan deserts (Magill 1976, Nash et al. 1977), its distribution is Texas, Oklahoma, New Mexico, Arizona, Utah, California, and northern Mexico. Apparently it has not yet been reported from the Mohave Desert of California, Nevada, and Utah (Harthill et al. 1979). The Utah locality is several hundred miles north of the nearest previously reported locality in Arizona. It also occurs at a relatively high elevation compared to the rest of its dis- tribution. The genus Pseudocrossidium is distin- guished from the related genera Barbiila, Tortula, and Bryoerythrophyllum by inter alia its differentiated perichaetial leaves, strongly revolute leaf margins, and lack of an adaxial stereid band in the costa (Zander 1979, 1981). Pseudocrossidium aureiim lacks many of the features of the genus, and sporophytes remain unknown (Zander 1981). The species has been illustrated by Bartram (1924), Steere (1938), Crum and Anderson (1981), and Zan- der (1981). Three additional species of Pseudocrossid- ium are known from western North America. These are P. hornschuchianum (Schultz) Zand., P. repUcatum (Tayl.) Zand., and P. revohitiim (Brid. in Schrad.) Zand. Pseu- docrossidium aiireum is distinguished from these species by its conspicuous, yellowish- reddish, smooth awn. The other three species are generally apiculate or mucronate. The Eurasian species P. hornschuchianum has Mountain Research Station. Universitv of Colorado, Nederland, Colorado 80466. 347 348 Great Basin Naturalist Vol. 47, No. 2 been reported from a botanic garden in Van- couver, British Columbia, and may be intro- duced (Tan et al. 1981). Another Eurasian species, P. revolutum , also occurs in Califor- nia, Oregon, Washington, Idaho, British Co- lumbia, Yukon Territory, and the Canadian Arctic Archipelago. The species P. revolutwn is an important component of the shrub- steppe of Oregon, Washington, and British Columbia (Mcintosh 1986). Pseiidocrossid- iiim replicatu7n has a distribution similar to P. aureum, although it is also found in the Andes of South America. Its North American distri- bution is Texas, New Mexico, Arizona, and Mexico (Zander 1979). Acknowledgments I thank Dr. R. Zander of the Buffalo Mu- seum of Science, who kindly confirmed the identification. The Mountain Research Sta- tion, under the direction of M. G. Noble, provided space and equipment, for which I am grateful. Literature Cited Bartram. E B 1924. Studies in Tortiila as represented in southern Arizona. Bull. Torrev Bot. Club 51: 335-340. Cronquist, a , A H Holmgren. N H Holmgren, and J L Reveal 1972. Intermountain flora. Vascular plants of the Intermountain West. Vol. 1. New York Bot. Card., New York. Crum, H A, AND L. E Anderson 1981. Mosses of East- ern North America. 2 vols. Columbia University Press, New York. Flowers. S 1973. Mosses; Utah and the West. Brigham Young University Press, Provo, L^tah. Haring. I 1961. A checkhst of the mosses of the state of Arizona. Bryologist 64: 224-240. Harthill, M P , D M Long, and B D Mishler. 1979. Preliminary list of Southern California mosses. Bryologist 82: 260-267. McIntosh, T T 1986. The bryophytes of the semi-arid steppe of south-central British Columbia. Unpub- lished dissertation, University of British Colum- bia, Vancouver. Magill. R E 1976. Mosses of Big Bend National Park, Texas. Brvologist 79: 269-295. Nash, T H III, S L. White, and J E. Marsh 1977. Lichen and moss distribution and biomass in hot desert ecosystems. Bryologist 80: 470-479. Stark, L R , and R C Castetter 1982. A preliminary list of bryophytes from the Organ Mountains, New Mexico. Brvologist 85: 307-311. Steere, W C 1938. Tor-tula. Pages 228-246 in A. J. Grout, Moss flora of North America north of Mex- ico. Vol. 1(3). A. J. Grout, Newfane. Tan, B C , R H Zander, and T Taylor 1981. Pseti- docrossidium hornschiichiamim and P. revolutum var. obtusulum in the New World. Lindbergia 7: 39-42. Zander, R H 1979. Notes on Barbula and Pseudocros- sidium (Bryopsida) in North America and an anno- tated key to the taxa. Phytologia 44: 177-214. 1981. Descriptions and illustrations of Barbula, Pseudocrossidium and Bryoerijthrophijllum (P. P.) of Mexico. Cryptogam., Bryol., Lichenol. 2: 1-22. 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TABLE OF CONTENTS Ecological comparison of sympatric populations of sand lizards {Cophosaurus texamts and Callisauriis draconoides) . Donald D. Smith, Philip A. Medica, and Sherburn R. Sanborn 175 Zoogeography of Great Basin butterflies: patterns of distribution and differentiation. George T. Austin and Dennis D. Murphy 186 Reproductive ecology of black-tailed prairie dogs in Montana. Craig J. Knowles 202 Field clinic procedures for diagnosing Echinococcus granulosus in dogs. Ferron L. Andersen and M. John Ramsay 207 Seed germination characteristics of Chnjsothamnus nauseosus ssp. viridulus (As- tereae, Asteraceae). M. A. Khan, N. Sankhla, D. J. Weber, and E. D. McArthur. 220 Development and longevity of ephemeral and perennial leaves on Artemisia triden- tata Nutt. ssp. wyoviingensis. Richard F. Miller and Leila M. Shultz 227 Pygmy rabbits in the Colorado River drainage. C. L. Pritchett, J. A. Nilsen, M. P. Coffeen, and H. D. Smith 231 Effects of land clearing on bordering winter annual populations in the Mohave Desert. Richard Hunter, F. B. Turner, R. G. Lindberg, and Katherine Bell Hunter 234 Occurrence of the musk ox, Symbos cavifrons, from southeastern Idaho and comments on the genus Bootherium. Michael E. Nelson and James H. Madsen, Jr 239 Effects of logging on habitat quality and feeding patterns of Abert squirrels. Jordan C. Pederson, R. C. Farentinos, and Victoria M. Littlefield 252 Parasites of the cutthroat trout, Salmo clarki, and longnose suckers, Catostomiis catostomus, from Yellowstone Lake, Wyoming. R. A. Heckmann and H. L. Ching. 259 Burrows of the sagebrush vole {Lemmiscus curtains) in southeastern Idaho. Tim R. Mullican and Barry L. Keller 276 Spider fauna of selected wild sunflower species sites in the southwest United States . G J. Seiler, G. Zolnerowich, N. V. Horner, and C. E. Rogers 280 Leptophlebiidae of the southwestern United States and northwestern Mexico (Insecta: Ephemeroptera). Richard K. Allen and Chad M. Murvosh 283 Flora of the Orange ClifiFs of Utah. L. M. Shultz, E. E. Neely, and J. S. Tuhy 287 Evaluation of the improvement in sensitivity of nested frequency plots to vegetational change by summation. Stuart D. Smith, Stephen C. Bunting, and M. Hironaka. 299 Notes on mycophagy in four species of mice in the genus Peromijscus. Chris Maser and Zane Maser 308 Bee visitors of sweetvetch, Hedysarum boreale boreale (Leguminosae), and their pollen-collecting activities. Vincent J. Tepedino and Mark Stackhouse 314 Observations on natural enemies of western spruce budworm {Choristoneura occiden- talis Freeman) (Lepidoptera, Tortricidae) in the Rocky Mountain area. Howard E. Evans 319 Plant community zonation in response to soil gradients in a saline meadow near Utah Lake, Utah County, Utah. Jack D. Brotherson 322 Age in relationship to stem circumference and stem diameter in cliffrose {Cotvania mexicana var. stansburiana) in central Utah. J. D. Brotherson, K. P. Price, and L. O'Rourke 334 Demography of black-tailed prairie dog populations reoccupying sites treated with rodenticide. R. P. Cincotta, D. W. Uresk, and R. M. Hansen 339 Western painted turtle in Grant County, Oregon. Jeffrey H. Black and Andrew H. Black 344 American swallow bug, Oeciacus vicarius Horvath (Hemiptera: Cimicidae), in Hirundo rustica and Petrochelidon pyrrhonota nests in west central Colorado. Thomas Orr and Gary McCallister 345 Pseudocrossidium aureiim (Bartr.) Zand. (Pottiaceae, Musci) new to Utah. John R. Spence 347 nC^ rHE GREAT BASIN NATURALIST Volume 47 No. 3 31 July 1987 Brigham Young University GREAT BASIN NATURALIST Editor. Stephen L. Wood, Department of Zoology, 290 Life Science Museum, Brigham Young University, Provo, Utah 84602. Editorial Board. Kimball T. Harper, Chairman, Botany and Range Science; Ferron L. An- dersen, Zoology; James R. Barnes, Zoology; Hal L. Black, Zoology; Jerran T. Flinders, Botany and Range Science; Stanley L. Welsh, Botany and Range Science. All are at Brigham Young University. Ex Officio Editorial Board Members include Bruce N. Smith, Dean, College of Biological and Agricultural Sciences; Norman A. Darais, University Editor, University Publications; Stephen L. Wood, Editor, Great Basin Naturalist. The Great Basin Naturalist was founded in 1939. The journal is a publication of Brigham Young University. Previously unpublished manuscripts in English pertaining to the biological natural history of western North America are accepted. The Great Basin Naturalist Memoirs series was established in 1976 for scholarly works in biological natural history longer than can be accommodated in the parent publication. The Memoirs appears irregularly and bears no geographical restriction in subject matter. Manuscripts for both the Great Basin Naturalist and the Memoirs series will be accepted for publication only^fter exposure to peer review and approval of the editor. Subscriptions. Annual subscriptions to the Great Basin Naturalist are $25 for private individuals and $40 for institutions (outside the United States, $30 and $45, respectively), and $15 for student subscriptions. The price of single issues is $12. All back issues are in print and are available for sale. All matters pertaining to subscriptions, back issues, or other business should be directed to the Editor, Great Basin Naturalist, Brigham Young University, 290 Life Science Museum, Provo, Utah 84602. The Great Basin Naturalist Memoirs may be purchased from the same office at the rate indicated on the inside of the back cover of either journal. Scholarly Exchanges. Libraries or other organizations interested in obtaining either journal through a continuing exchange of scholarly publications should contact the Brigham Young University Exchange Librarian, Harold B. Lee Library, Provo, Utah 84602. Manuscripts. See Notice to Contributors on the inside back cover. 10-87 650 31906 ISSN 017-3614 The Great Basin Naturalist Published AT Provo, Utah, by Brigham Young UMVERSiri' ISSN 0017-3614 Volume 47 31 July 1987 No. 3 RELATIONSHIP OF WESTERN JUNIPER STEM CONDUCTING TISSUE AND BASAL CIRCUMFERENCE TO LEAF AREA AND BIOMASS' Richard F. Miller", Lee E. Eddleman^, and Ravmond F. Angell" Abstract — The ability to measure leaf area and biomass on a plant conimunit\' basis has nian\- important ecological applications. These include quLntification of gas exchange, use of water resources on the site, nutrient pools, and construction of models simulating production and resource allocation. To test a nondestructive technique for estimat- ing leaf area and leaf biomass of western juniper (Juuipcrus occideutalis Hook. ), sapwood area and basal circumference were evaluated as predictors of total leaf biomass and leaf area. Nineteen trees, ranging in size from 9.0 to 263 cm in circumference, were destructively sampled. The entire leal biomass was harvested and measured, and regression ecjuations were developed. Both sapwood area and basal circumference significantK (P < .01) correlated with projected leaf area and leaf biomass (r values = 0.98). Knowledge of leaf area and leaf biomass on a plant community basis has many important ecological applications. Leaf area is important in gas exchange, the hydrologic cycle, and models simulating production and resource allocation. Leaf area is essential in assessing recovery rates in forested ecosystems follow- ing disturbance (Sollins et al. 1974). Waring et al. (1980) also found leaf area in combination with the annual growth increment of a tree (annual growth increment cm'^:leaf area m") a useful inde.x for assessing vigor in conifers. Defining leaf biomass for a dominant species describes the size of a major nutrient and carbon pool in a plant community. Measuring leaf area, on a whole plant basis, is difficult because of a high degree of variabil- ity among plants and across sites. Leaf area measurements are also labor intensive and often require destructive sampling. As a re- sult of these difficulties, little information is available on leaf area in range ecosystems. Foresters have successfully used sapwood area to indirectly estimate leaf area. Shinozaki et al. (1964) concluded that a constant cross- sectional area of conducting tissue supports a given unit of leaves. Since that time, re- searchers have found close relationships be- tween sapwood area and leaf area (Dixon 1971, Crier and Waring 1974, Waring et al. 1977, Snell and Brown 1978, Whitehead 1978, Kaufmann and Troendle 1981, Marchand 1984). The correlation between leaf area and area of conducting tissue is pre- sumably a function of the physiological bal- ance between water demand by the crown and the ability of the stem to conduct water (Kaufmann and Troendle 1981). Application of this hypothesis, sometimes called the pipe model theorv, is discussed bv Waring et al. (1982). Estimating the impact of western juniper (Jiiniperus occidentalis Hook.) woodlands on nutrient resources and the hydrologic cycle Oregon State .Agricultural Experiment Station Technical Paper No. 8239. "Oregon State .Agricultural Experiment Station and USDA-ARS. Eastern Oregon .Agricultural Research Center. Star Rt. 1, 4.51 H\\-\ . 205, Bums, Oregon 97720, Rangeland Resources Department, Oregon State University. Cor\allis, Oregon 97331. 349 350 Great Basin Naturalist Vol. 47, No. 3 requires estimates of leaf area and biomass. The objective of this study was to develop a useful, nondestructive technique for estimat- ing leaf area and leaf biomass of western ju- niper woodlands by testing the pipe model theory. To do so, we evaluated the relation- ship between sapwood area and basal circum- ference with leaf biomass and leaf area. Materials and Methods The study site is at the Squaw Butte Experi- mental Range on the northern fringe of the Great Basin in southeastern Oregon, 57 km west of Burns. The 40-year mean precipita- tion for this area is 300 mm. The study site is a mountain big sagebrush/Idaho fescue {Artemisia tridentata ssp. vaseyana/Festuca idahoensis) habitat type (Winward 1970) at an elevation of 1,350 m. Soils are fine-loamy, mixed, frigid Aridic Durixerolls, approxi- mately 112 cm deep to columnar basalt. Thirteen healthy trees ranging from 9 to 263 cm in circumference (2.9-84 cm in di- ameter) at the litter surface were selected for destructive sampling. Trees selected had full canopies showing no signs of insect damage or disease. Trees were subjectively selected so four trees would fall within each of three size classes: 2.5-6 cm, 6-20 cm, and 20-45 cm in basal diameter. The thirteenth tree was se- lected to represent the largest trees within the stand. All trees were single stemmed. Sam- pling was conducted from 20 June to 1 Octo- ber 1984. Maximum error caused by the dura- tion of sampling during the growing season is estimated to be 15% (Miller and Shultz 1987). Trees were divided into two segments along the main trunk (base and midsection). Sap- wood area was measured at both points, and all foliage on branches attached to the main trunk above the point of sapwood measure- ment and basal circumference was removed, dried at 60 C for 72 hours, and weighed. Sap- wood area and basal circumference were mea- sured at the litter surface because of tree growth form. Sapwood was easy to distinguish from heartwood, particularly after several days of air drying. A piece of acetate was laid over the stem base and the sapwood area was outlined. A cut-out of the outlined sapwood was constructed from black paper and the area of the paper measured on a leaf-area meter. All or most of the limbs were removed prior to felling the tree. One sample of approximately 0. 1 kg of fresh leaf material was harvested from each tree during defoliation, sealed in plastic bags, and stored in a freezer for later evaluation of leaf weight to leaf area relation- ships. Frozen samples of foliage were thawed in the lab and their areas measured on a Li-Cor leaf-area meter. Foliage was assumed to be cylindrical, so leaf-area readings were multi- plied by TT to compute total exposed leaf sur- face. Due to partial overlapping of lower adja- cent leaves, total leaf surface area is underestimated (we estimated approximately 10%). Estimates of total gas exchange, how- ever, will not be over- or underestimated as long as measurements per unit leaf area are also based on exposed leaf area. Following leaf-area measurements, samples were dried at 60 C for 72 hours, weighed, and added to the total foliage weight for the tree. Linear regression procedures were used to establish a relationship between leaf biomass (dry weight) and leaf area for both populations of trees. These equations were then used to con- vert total harvested leaf biomass to total leaf area for each tree. In the following year a second population (n = 6) of trees at two sites in central Oregon, 175 km west of Squaw Butte, was selected for study. The relationship between sapwood area and basal circumference with leaf area in the second population was compared to the first. Habitat types at both locations were sim- ilar to the site sampled at Squaw Butte. Trees, ranging in circumference from 11 to 47 cm, were sampled similarly to those in the previ- ous year. Values representing the ratios of leaf area (m^) to sapwood area (cm") and leaf area (cm ) to leaf weight (g) were derived for each of the trees sampled. Student's t-test was used to test the null hypothesis that mean ratios were identical between the two populations of trees sampled. The null hypothesis was accepted and data for the two populations were pooled for final analysis. Basal circumference, basal sapwood area, and midsection sapwood area served as inde- pendent variables in regression analysis aimed at predicting total leaf area or total leaf biomass of the supported foliage. Possible dif- ferences in relationships derived from basal sapwood areas and midsection sapwood areas July 1987 Miller et al. : Juniper 351 Table L Regression equations, standard error of estimate (Sy.x), and correlation coefficents for estimating leaf biomass and leaf area. Independent Dependent Correlation n variable (X) variable (Y) Regression equation Sy.x coefficient 19 Leaf wt (g) Leaf area (cm^) Y = -40.566 + 65.238X 107.010 0.978 19 Sapwood area (cm^) Leaf biomass (kg) Y = 1.237 + 0.024(X) + 0.00005(X^) 2.735 0.987 19 Sapwood area (cm^) Leaf area (m^) Y = 8. 145 + 0. 155(X) + 0.00035 (X') 17.822 0.987 19 Basal circ. (cm) Leaf biomass (kg) Y = -5.381 + 0.352(X) 3.570 0.976 19 Basal circ. (cm) Leaf area (m^) Y = -35.036 + 2.296(X) 23.294 0.976 13' Sapwood area (cm^) Leaf biomass (kg) Y = 0.473 + 0.040 (X) 0.445 0.938 13 Sapwood area (cm") Leaf area (m^) Y = 0.220 + 0.504(X) - 0.0024 (X^) 3.250 0.906 13 Basal circ. (cm) Leaf biomass (kg) Y = -1.046 + 0. 143 (X) 0.391 0.953 13 Basal circ. (cm) Leaf area (m^) Y = -4.007 + 0.767(X) 3.763 0.862 Regression equations with n - 13 were developed for trees with basal circumferences less than 50 < 2500n LEAF WEIGHT (g) Fig. 1. Regression line and data points for leaf drv weight and leaf area for western juniper with n 107.010, and r = 0.978. 19, Sy.x were evaluated by comparison of regression lines (Neter and Wasserman 1974). Regres- sion lines were also compared between all trees sampled (n =^ 19) and with the big tree (263 cm in circumference) excluded. Appro- priateness of the models finally selected to predict total leaf area or biomass was evalu- ated by ordering data in accordance with the independent variable and examining the residuals. Rank correlation of residuals with independent variables (Neter and Wasserman 1974) failed to reject the null hypothesis of constant variance (P > .05). Results A strong linear relationship between leaf weight and surface area of leaves allowed us to 352 Great Basin Naturalist Vol. 47, No. 3 500 - 100 150 200 BASAL CIRCUMFERENCE (cm) Fig. 2. Regression line and data points for basal circumference at the litter surface and total leiif area for western juniper with n - 19, Sy.x 23.294, and r 0.976. estimate leaf area by measuring leaf weight (Table 1, Fig. 1). Sapwood area and basal cir- cumference were significantly (P < -01) corre- lated with leaf area (Fig. 2). Estimates, how- ever, can be improved for small trees (primarily for trees with basal diameters < 20 cm) if the regression equation developed for trees less than 50 cm in circumference is used. The large tree did not significantly (P > . 10) change the slope or intercept of the regression line when included with the 18 smaller trees (Neter and Wasserman 1974). Relationships between leaf area and sap- wood area measured at the tree base, and leaf area and sapwood area midway up the trunk were significantly different (P < .05). At the tree base 1 cm^ of sapwood supported 0.45 m" of leaf area. At the tree's midsection 1 cm" of sapwood supported 0.64 m" of leaf area. Gholz (1980) reported a leaf-area: sapwood ratio of 0.56 for western juniper when sapwood was measured at DBH. Discussion Results of this study support use of the pipe model theory on western juniper. Both sap- wood area and basal circumference are useful measurements for estimating total leaf area or leaf biomass. Caution should be used when extrapolating ^^quations to trees larger than the largest tree (diameter 82.8 cm, height — 9.8 m) measured in this project, since the last data point strongly influences the shape of the curve. Few trees, however, in a mature stand of western juniper will be substantially larger. The leaf-area model using basal cir- cumference may also perform poorly on deca- dent stands of western juniper. Because young trees usually constitute only a small proportion of total leaf area or biomass in mi.xed-aged stands of juniper, the fact that the curve does not pass through the origin will add little error to an overall estimate of total leaf area for a western juniper woodland. If the stand is young, however, with numerous basal circumferences less than 50 cm, the re- gression model developed for small trees will improve the estimates. The strong correlation between basal cir- cumference and total leaf area is probably due to the significant (P < .01) relationship be- tween sapwood area and basal circumference July 1987 Miller ETAL: Juniper 353 (r - 0.98). Ovington et al. (1968) found a high correlation between bole cross-sectional area and leaf area in young Pinus radiata. Cross- sectional area, however, closely correlated with sapwood area since young trees have little or no heartwood. The relationship between sapwood area and leaf area in western juniper changes above the litter surface. Less sapwood area is required to support a unit of leaf area as one moves up the trunk. This relationship, sup- ported by both our work and that of Gholz (1980), may be partially due to butt swell. Waring et al. (1982) also reported a reduction in sapwood area along the trunk of Pseudot- siiga menziesii below the live crown. In Chamaecyparis obtiisa, Morikawa (1974) con- cluded that linear correlations should not ex- tend much below breast height, particularly below butt swell. Because of western ju- niper's growth form, however, sapwood area should be measured at the base. If multiple stems are present, each stem circumference should be measured separately. Ratio of leaf area to sapwood cross-sectional area (leaf area m": sapwood area cm") reported for 14 other conifer species ranged from 0. 16 to 0.75 (Waring et al. 1982). In general, larger coefficients are found in tree species growing in more mesic environments, while trees with smaller coefficients are typical of drier envi- ronments (Kaufmann and Troendle 1981, Waring et al. 1982). When compared with other conifer species, the ratio between total leaf area to sapwood area in western juniper (0.45) is higher than might be expected for a tree growing in a relatively dry environment. Western juniper, however, has relatively low stomatal conductance rates per unit leaf area compared with other conifers and contains leaf morphological characteristics which avoid drought and reduce moisture loss (Miller and Shultz 1987). Factors reducing water loss through transpiration from the crown would reduce the amount of sapwood tissue required to support a unit of leaf area. Gholz (1980) used basal circumference measurements to estimate leaf biomass and leaf area for western juniper. His study plots are within 1 km of our study plots, located 175 km west of Squaw Butte. His model (In leaf biomass = -4.243 + 1.5606 In [basal circum- ference]) fit our data closely for trees < 30 cm in circumference, but consistently underesti- mated leaf biomass for trees 30 to 137 cm in circumference by 24 to 47%. Differences may be attributed to sampling procedures. Gholz subsampled trees (n = 10) instead of sampling entire trees. We suspect the difficulty of accu- rate subsampling would increase with an in- crease in tree size. Another source of differ- ence between the two studies was the relationship between leaf weight and leaf sur- face area. Our ratios (cm^g) at both sites were larger than Gholz's. The relationship between sapwood area and leaf area in western juniper did not change between locations. We hypothesize that geographic range and environmental con- ditions between these two study sites were not large enough to cause differences in leaf- area:sapwood-area coefficients. Marchand (1984) reported no change in leaf-area: sapwood-area coefficients for Abies halsamea and Picea ruhens growing across an environ- mental gradient. Variation, however, in the relationship between sapwood area and leaf area has been reported within species with large geographical distributions (Waring et al. 1982). An example is Pseudotsuga menziesii with a leaf-area: sapwood-area (m"/cm") coeffi- cient of 0.54 for Pacific Coastal trees (Waring et al. 1982) and 0.34 for trees growing in the Rocky Mountains (Snell and Brown 1978). Total leaf surface area or biomass for a west- ern juniper woodland can be estimated by multiplying the mean basal circumference or sapwood area of trees in the stand (obtained through subsampling the stand) by tree den- sity (obtained from subsampling or aerial pho- tos). Estimates of basal circumference or sap- wood area of a western juniper woodland should provide good estimates of total leaf area or leaf biomass. Estimates based on sap- wood areas will probably be more reliable, especially in decadent stands of juniper, than estimates made from basal circumference. Models based on circumference, however, provide us with a nondestructive and less labor-intensive means of estimating leaf areas. Development of models estimating leaf biomass or leaf area for various plant species will enhance our ability to determine their impact on the hydrologic cycle through tran- spiration and to identify total carbon fixation capabilities and nutrient pools. 354 Great Basin Naturalist Vol. 47, No. 3 Acknowledgments The research on which this report is based was jointly financed by the United States Department of Interior, Geological Survey, through the State Water Resources Research Institute, authorized by the Water Resources Research Act of 1984 (P.L. 98-242), the United States Department of Agriculture, Agricultural Research Service, and Eastern Oregon Agricultural Research Center, Squaw Butte Station, Agricultural Experiment Station. Contents of this publication do not neces- sarily reflect the views and policies of the U.S. Department of Interior. Literature Cited Dixon, A. F. G 1971. The role of aphids in wood forma- tion. J. Appl. Ecol. 8: 165-179. Gholz, H. L 1980. Structure and productivity oijunipe- rus occidentalis in central Oregon. Amer. Midi. Nat. 103:2.51-261. Crier, C. C, and R. H Waring. 1974. Conifer foliage mass related to sapwood area. For. Sci. 20: 205-206. Kaufmann, M R , AND C a Troendle. 1981. The rela- tionship of leaf area and foliage biomass to sap- wood conducting area in four subalpine forest tree species. For. Sci. 27: 477-482. Marchand, P J. 1984. Sapwood area as an estimator of foliage biomass and projected leaf area for Abies halsamea and Picea rubens. Canadian J. For. Res. 14: 85-87. Miller, R F , and L I Shultz 1987. Water relations and leaf morphology oi Juniperus occidentalis in the northern Creat Basin. For. Sci. (in press). Morikawa, Y 1974. Sap flow in Chamaecyparis obtusa in relation to water economy of woody plants. Tokyo Daigaku Nogakubu Enshurin Hokoku, Forests 66: 251-297. Neter, J , and W. Wasserman. 1974. Applied linear statistical models. Richard D. Irwin Inc., Illinois. 816 pp. Ovington. J D , W C. Forrest, and J. S Armstrong. 1968. Tree biomass estimation. In. H. E. Young, ed. , Symposium on primary productivity and min- eral cycling in natural ecosystems. University of Maine, Orono. Shinozaki, K.. K. Yoda, K. Hozumi, andT Kira. 1964. A quantitative analysis of plant form — the pipe model theory. 1. Basic analyses. Japanese]. Ecol. 14: 97-105. Snell, J. K A, and J. K Brown 1978. Comparison of tree biomass estimators — dbh and sapwood area. For. Sci. 24: 4.55-457. Sollins, p., R H Waring, and D. W. Cole. 1974. A systematic frame work for modeling and studying the physiology of coniferous forest ecosystem. Pages 7-20 in R. H. Waring and R. L. Edmonds, eds. , Integrated research in the Coniferous Forest Biome. Bull. 5. Coniferous Forest Biome, Seattle, Washington. Waring, R H , H L Cholz, C C Crier, and M L Plum- MER. 1977. Evaluating stem conducting tissue as an estimator of leaf area in four woody an- giosperms. Canadian J. Bot. 55: 1474-1477. Waring, R H , P E Schroeder, and R Oren 1982. Application of the pipe model theor>' to predict canopy leaf area. Canadian J. For. Res. 12: .556-.560. Waring, RHWC Thies, and D.Mescato. 1980. Stem growth per unit leaf area: a measure of tree vigor. For. Sci. 26: 112-117. Whitehead, D 1978. The estimation of foliage area from sapwood basal area in Scots pine. Forestry 51: 137-149. Win WARD, A H 1970. Taxonomic and ecologic relation- ships of big sagebrush complex in Utah. Unpub- lished dissertation. University of Idaho, Moscow. 80 pp. PARASITES OF THE BOWHEAD WHALE, BALAENA MYSTICETUS Richard A. Heckmann', Lauritz A. Jensen', Robert G. VVarnock^ and Bruce Coleman' Abstract —Blood, tissue, and organ samples from five bowhead whales were examined for ecto- and endoparasites. Two species of protozoans, four genera of diatoms, one species of trematoda, two species of nematoda, and one species of amphipoda "louse" were found. No blood parasites were recovered. The larval anisakid nematode, found in the submucosa of the forestomach of one whale, generated a prominent inflammatory response. Protozoans found in contents of the colon included a flagellate and a sarcodinan. The sarcodinan, which was common in the colon contents of one whale, belongs to the genus Entamoeba and probabK- represents an undescribed species. Ogomogaster plicatus, a trematode, was also identified. The data from this study are compared with previous lists of parasites for the bowhead whale and two other species of baleen whales. From the results presented, the previous list of parasites for the bowhead whale has been expanded to include eight additional genera and species. Cetaceans throughout the world are known to be infested and infected with parasites (Dailey and Brownell 1972). This does not necessarily mean that the hosts are seriously affected or damaged by the symbionts. If, in addition to the parasite load, stress and/or nutritional imbalances occur, the animal may become weak and possibly die. Stroud and Roffe 1979, Dailey and Walker 1978, Martin et al. 1970, Ridgway and Dailey 1972 have indicated that helminths were a possible fac- tor for cetacean strandings. Stranded animals exhibited disoriented behavior with an obvi- ous loss of equilibrium. Necropsy results of these animals showed that the central nervous system was infected with trematodes of the genus Nasitrema, thus providing at least a partial explanation for the whale strandings. The nematode Sternurus, located in the ears of cetaceans, is also a potential factor for cetacean strandings. The brains of these stranded animals showed lesions induced by trematode eggs. Activities associated with offshore oil and gas development, such as those in the Beau- fort Sea, may increase the stress to bowhead whales and thereby allow an increase in para- site burden. It would be advantageous to de- termine the types of parasites harbored by bowhead whales for such knowledge would help in understanding what effect contact with spilled oil may have on cetaceans. The primary objective of this study was to estimate the parasite burden of the bowhead whale, Balaena mysticetus, through the ex- amination of the selected specimen materials obtained from subsistence harvested whales. Methods Specimen materials were obtained from five bowhead whales taken off Barrow, Alaska, in 1980 by Eskimo hunters. Tissue samples, including colon contents, were collected on- site (Albert 1981), fixed in 10% formaUn, and shipped by air freight to the parasitology labo- ratory at Brigham Young University. Blood smears from whales were air dried and sent with the above samples. The samples were processed as follows; Tissues and organs,— After the code num- ber for the whale was recorded, each speci- men was weighed, measured, and then dis- sected to determine the presence of parasites. Intestinal segments were cut lengthwise, af- ter which the lumen was examined for macro- scopic parasites. Samples of lumen contents were placed on glass slides and examined with a light microscope. Slides of lumen contents from the intestine were also fixed and stained with iron haemotoxylin, trichrome, or Giemsa-Wrights stains to enhance parasite presence. After the staining procedure was completed, each slide was examined for para- Department of zooiog\-. Brigham Young University, Provo, Utah 84602. ^Department of MicrobiologN-, University of Health Sciences. Kansas Cit\', Missouri 64124. Department of Biolog)-, Westminster College, Salt Lake City, Utah 84101, 355 356 Great Basin Naturalist Vol. 47, No. 3 Table 1. Bowhead whale, Balaena mijsticetus. speci imens examined for parasites. Whale number Specimen Specimen (Code) Type of specimen length (cm) weight (kg) 80B1 Blood smears (4 slides) Intestine segments: — — A 8.3 7.3 B 107 8.6 C 99 3.15 D 134 2.25 80B2 Blood smears (2 slides) Intestine segments: — — A 87 6.75 B 59 3.15 Liver sample — 2.7 80B7 Blood smears (2 slides) Intestine segments: — — A 78 1.21 B 75 2.41 C 44.5 4.70 Liver sample — 2.3 Diaphragm sample — 0.7 Colon contents (1.5 liters) — — 80B8 Blood smears (2 slides) — — Intestine segment 96 4.5 Diaphragm sample — 0.6 80B9 Louse on baleen — — Liver sample — 1.35 Colon segment 95 9.9 sites. Pieces of liver and diaphragm were placed in separate jars containing a standard digestive enzyme solution (pepsin and hy- drochloric acid in water) for 24-48 hours at 37 C. This procedure digests host tissue but not nematode larvae and adults. The material was then centrifuged and examined with a light microscope. Colon contents. — Formalin-fi.xed colon contents were examined following the same procedure as outlined for lumen contents from the intestine. The same stains were used for the preparation of permanent slides. Blood smears. — Standard methods were followed for the examination of blood smears for parasites. A combination Giemsa-Wrights stain was used for maximum staining ot any intracellular and extracellular parasites that might be present. Each stained slide was ex- amined for at least 10 minutes at 400X and 1,000X magnification. Parasite procedure. — Two procedures were used for flukes. Fluke specimens were fixed in alcohol-formalin-acetic acid (AFA) and gluteraldehyde. Those fixed in AFA were stained with semichon's carmine and mounted on glass slides. Gluteraldehyde fixa- tive in an acrolien buffer was used for flukes to be examined with scanning electron mi- croscopy (SEM). For SEM each fluke was critically point dried, mounted on a specimen holder, coated with gold for three minutes with a CS mini-coater sputter, and then viewed with an AM RAY lOOOA scanning elec- tron microscope operating at 20 Kv. A whale louse, Cyamus ceti, was also examined with SEM. A paraffin block of tissue containing a larval nematode (Migaki 1981) was prepared for his- tological evaluation, and sections were stained with haemotoxylin and eosin, tri- chrome and periodic acid-Schiff. An intact ne- matode fotind free in the stomach of a bow- head whale was also examined. Skin samples representing normal and eroded areas were provided for parasite exam- ination (Haldiman et al. 1981). These samples were prepared for SEM and light microscopy as explained for flukes and nematodes. Results of the parasite examination were summarized and compared with the existing list for the bowhead whale, B. mysticetus. July 1987 Heckmann etal: Whale Pamsites 357 Table 2. Results of examining bowhead whale, Balacna mysticetus. tissue samples, with process procedi summarized, for parasites. Whale Parasites number Tissue examined Special procedures observed 80B1 Bloood smears Intestine segments: Giesma-Wright stain None A None B None C None D None Intestinal contents Larval nematode 80B2 Blood smears Intestine segments: Giesma-Wright stain None A 4 trematodes B 2 trematodes Liver sample None *Liver sample **Digestive fluid None 80B7 Blood smears Intestine segments: Giesma-Wright stain None A None B None C 8 trematodes Liver sample None * Liver sample **Digestive fluid None Diaphragm sample None * Diaphragm sample **Digestive fluid None Colon contents Fixed in formalin 2 protozoan species stained with Amoeboid form three stains Flagellate form SOBS Blood smears Giesma-Wright stain None Intestine segment 10 trematodes Diaphragm sample None * Diaphragm sample ** Digestive fluid None S0B9 Baleen piece "Louse" attached (Cijamus sp.) Liver sample None * Liver sample **Digestive fluid None Colon None *Small pieces were removed from the samples of liver and diaphragm * Digestive fluid: An aqueous solution of pepsin and hydrochloric acid and placed in breakers containing digestive fluid, used to digest host tissue and leave nematodes intact. gray whale, EschhcJitus rohustus. and blue whale, Balaenoptera miisculus. Results Table 1 lists the specimens obtained for this study, with data on whale code number, tvpe of tissue, and amount. The results of examin- ing the pieces of tissue are listed in Table 2. Parasites obtained from these bowhead whale samples are indicated in the table, after which each parasite is listed separately and dis- cussed. Comments on Parasites Observed Two species of protozoa, one amoeboid and one flagellated, were found in the formalin- fixed colon contents of one whale (80B7; Table 2). The amoeboid form appears to be a species new to science, while insufficient numbers of the flagellate negated further taxonomic study. Both represent the first known proto- zoa observed and described from bowhead whale intestinal contents. Amoeboid Protozoan Fig. 1 An unidentified amoeba from the colon contents of animal 80B7 had the following characteristics, based on the observation of 100 specimens in stained and fixed prepara- tions: trophozoite and cyst stages, cysts con- taining one to four nuclei, cysts oval in shape ranging from 15 to 18 |xm in diameter, nuclei 358 Great Basin Naturalist 1 \ Jul */ Vol. 47, No. 3 Fig. 1. Photomicrographs and hne drawings of an amoeboid parasite (Entamoeba sp.) from the colon contents of a bowhead whale, Balaena mysticetus. Note the pseudopod (P) characteristic of this protozoan group, both single (n) and multinucleate (mn) cells, vacuoles (v), granular cytoplasm (g), and chromatoid body (c) (1,000X for photomicrographs). spheroid to ovoid, nuclei randomly dis- located in uninucleate forms, nucleus occu- tributed for multinucleate forms and centrally pies approximately 10% of the cell volume, July 1987 Heckmann etal: Whale Parasites 359 Fig. 2. Photomicrographs and Hne drawing of a flagel- lated protozoan found in the colon contents of Balaena mysticetus. Flagella (f) and a single nucleus (n) are visible, both characteristic of flagellated protozoa (1,000X for pho- tomicrographs). pseudopodia observed, vacuoles vary in num- ber, both food and water vacuoles present chromatoidlike bodies in cytoplasm, periph- eral nonchromatic granules, it was common in the intestinal contents of one bowhead whale. Based on these observations and the similarity of characteristics (Kudo 1966), we consider this amoeba a species of Entamoeba Casagrandi & Barbagallo, 1895. Thus, based on Levine et al. (1980), the classification for this amoeba would be: Phylum: Sarcomastigophora Subphylum: Sarcodina Class: Lobosea Order: Amoebida Family: Endamoebidae Genus: Entamoeba sp. From further literature research and obser- vations of this protozoan, the correct species will be determined. The genus Entamoeba is common in many vertebrate species (Olsen 1974), and several species are parasitic, dam- aging the intestinal lining of the host (Faust 1975). Flagellated Protozoan Fig. 2 From the same bowhead whale (80B7) for- malin-fixed colon contents containing an amoeboid protozoan, three flagellates were observed in the material examined. Insuffi- cient specimens were available for species de- termination. The single-celled organism ap- peared to be much like a species of Chilomastix (Faust et al. 1975) or the "pear"- formed Hexamita (Olsen 1974). Diatoms Phylum: Chrysophyta: (Plant Kingdom) Genera: Cocconeis sp. Statironeis sp. Navicula sp. Gornphonema sp. Four genera of diatoms were observed on the epidermis (Figs. 3, 4, 5, 6). Diatoms are plants belonging to the phylum Chrysophyta, which is characterized by silicon cell walls (Fuller and Tippo 1960). They are found in both fresh and salt water and are composed of single cells. There are a large number of di- atom species. We observed diatoms on the normal whale epidermis surface and in the eroded areas of the epidermis (Figs. 7, 8, 9). The forms observed on the epidermis surface are common to cetacean hosts (Nemoto 1956, Nemoto et al. 1977, Omura 1950). Great Basin Naturalist Vol. 47, No. 3 Fig. 3. Scanning electron microscope (SEM) micrographs (3a, 3b) and light microscope micrograph (3c) of one of the most common diatoms, Cocconeis (arrowheads), observed during this study. Fig. 3b shows the extent to which Cocconeis extends into the epidermis of whale skin. The micron bar at the bottom of each micrograph (SEM) is used to measure object size. Filamentous bacteria (b) and whale red blood cells (r) are present on one micrograph (3a). The light microscope micrograph (3c) is magnified 400X. Fig. 3b. July 1987 Heckmann etal.: Whale Parasites 361 Fig. 3c. I , 1 '> '^ s • • j(j.-; •1^ . V *• • - ^ . . » •,. • Fig. 4. Stauroneis sp. (s) present in a section of bow- head whale epidermis, 4a (400X) and 4b (1,000X). Helminths Three species of worms were observed dur- ing the examination of whale tissue. One was a digenetic trematode and the other two were roundworms. Ph\lum: Class: Family: Genus, Species: Flukes Platyhelniinthes Trematoda (Digenea) Notocotylidae Ogmogaster plicattts Species of the genus Ogmogaster have been reported from both pinnipeds and cetaceans. In the present study 24 specimens were col- lected from intestinal segments of three bow- head whales (80B2, 80B7, 80B8). Reported in the Antarctic and northern Pacific oceans, these flukes apparently cause no damage to the host (Dailey and Brownell 1972). The anatomy of O. plicatus from the bowhead whale was studied and appears to be similar to the antarctic form (Rausch and Fay 1966). The fluke has been reported recently from the bowhead whale (Shults 1979) and has been compared with O. antarcticus, O. trilineatus, and O. pentalineatus (Rausch and Rice 1970). One of the many characteristics for the species oi Ogmogaster is the number of parallel, Ion- 362 Great Basin Naturalist Vol. 47, No. 3 Fig. 5. SEM micrograph of a diatom (n) Navicula sp. Note micron bar at bottom of micrograph. Fig. 6. The diatom (g) Gomphonema sp. on the surface of bowhead whale skin(s). Note filamentous bacteria (b) and a biconcave erythrocyte (r) (220X). July 1987 Heckmann etal; Whale Parasites 363 Fig. 7. SEM micrograph of bowhead whale epidermis from an area without prominent erosions of the epidermis. Note filamentous bacteria (b) and diatoms (d) such as Gomphonema and Cocconeis on the surface of the skin (220X). Fig. 8. Bowhead whale epidermis: 8a, the free surface of the skin with initial erosion (lOOX); 8b (lOOX) and 8c (400X), the erosion (e) process continuing and the presence of bacteria (b) and diatoms (d) in the eroded area. gitudinal ridges on the ventral surface. Og- mogaster plicatus is characterized by 19-28 ridges with an average of 23 (Rausch and Fay 1966). Figure 10 represents the dorsal and ventral surfaces of O. plicatus collected dur- ing this study. The life cycle is unknown for this species. Anisakid-type Larvae Phylum Order: Family: The piece of bowhead forestomach mounted in paraffin contained larval ne- matodes that appeared to be an anisakid-type Nematoda(The Aschelminthes, Barnes 1980) Ascaridata Anisakidae 364 Great Basin Naturalist Vol. 47, No. 3 Fig. 9. SEM micrograph representing erosions (e) in the epidermis of whale skin, which usually contains numerous diatoms and bacteria (llOX). larva (Schmidt and Roberts 1984, Migaki et al. 1982) (Fig. 11). No adult stages of this round- worm were observed in examined samples. A description of the life cycle of Anisakis is found in parasitology texts (Faust et al. 1975, Schmidt and Roberts 1984) and in recent pub- hcations (Smith 1971, Wootten and Waddell 1977, Smith and Wootten 1978, Wootten 1978, Heckmann and Otto 1985). Adult stages of this nematode are characteristically found in stomachs of carnivorous marine mammals (Smith and Wootten 1978). The examined ne- matode was in the migratory larval phase of its life cycle. Larval characteristics for species of Anisakis include: esophagus with a ven- triculus that ends obliquely at its junction with the intestine (Hadidjaja et al. 1978), no ventricular appendage nor intestinal caecum, the tail is blunt and terminates in a distinct mucron (Smith and Wootten 1978, Shiraki 1974, Oshima 1972), a prominent boring tooth (mucron) present (Smith and Wootten 1978). For the life cycle of Anisakis sp., euphausiids (Crustacea) are probably the most important intermediate host (Smith 1971, Smith and Wootten 1978). Euphausiids are a source of food for the bowhead whale (Lowry and Burns 1979, Lowry and Burns 1980, Lowry and Frost 1984). After examining serial sections of the larval nematode, we noted the following characteristics: no bursa or prominent teeth, blunt tail with mucron remains present, trilobed lips, dentigerous ridge on anterior end, no terminal enlarge- ment for the esophagus, no alae, and overlap- ping annulations on the surface. The ne- matode is apparently a species o( Anisakis. Because we lacked adult worms, which are required for a definitive taxonomic assign- ment (Smith and Wootten 1978), and because of the taxonomic confusion of the family An- isakidae, the larval nematode will be referred to as "anisakid-type' (Schmidt and Roberts 1984). Yokogawa and Yoshimura (1967) re- ported larval anisakiasis in the gastrointestinal tract of Japanese people. Recently, cases of anisakiasis have been reported in the United States (Schmidt and Roberts 1984), and larval stages of this roundworm, obtained from salmon harvested at Barrow, Alaska (Heck- mann and Otto 1984), were sent to this labora- tory. Anisakid Roundworm Phylum: Nematoda Order: Ascaridata One worm found free in the stomach of animal (80B1) was too poor to evaluate prop- erly; therefore, it is impossible to obtain a complete taxonomic description. This round- worm appears to be Anisakis or Contracae- ciun. Members of these genera are among the most common parasites in the stomachs of pinnipeds (Dailey and Brownell 1972). July 1987 Heckmann et al.; Whale Parasites 365 Jk ^^^ ' ^■HHV^ ^^»aES>iik^ ^^^ r *_ w ,^. J »*- t" ' . . 4^ k * . w- ^^^ ■9® (3 " ' ' V' '^'^ *:-':'';.: :•„' ; ''^1 '^'^ ^- (Mh ^ Fig. 10. SEM micrographs of Ogmogaster plicatus: 10a, dorsal surface of the trematode (18X); 10b, ventral surface (25X). Note the characteristic lateral varigations (arrowheads) for this species and the longitudinal ridges on the ventral surface. Whale Lice Phylum; Arthropoda Class: Crustacea Order: Amphipoda Genus, Species: Cijamus ceti, highly modified for a parasitic mode of life Cyamids have a vestigial abdomen, but the body, an exception among amphipods, is broad, depressed, and bears large legs (Leung 1967). The cyamids of whales have a high degree of host specificity; however, the same species that occurs on the bowhead whale is 366 Great Basin Naturalist Vol. 47, No. 3 Ki'Ji Fig. 11. The larval anisakid-type roundworm (arrow- heads) found encysted (c) in the suhmucosa (sm) of the howhead whale forestomach. Note the inflammatory (i) response around the nematode (lOOX). found on gray whales. The species Cyamus ceti is one of the most common parasites ob- served during this and a previous study (Heckmann et al. 1980, Heckmann 1981). Figure 12 represents the ventral surface of a whale louse. Note the enlarged appendages with numerous hooks. The mouthparts, as well as the appendages, are highly modified for the ectoparasitic mode of life. The cyamids have a direct life history with the young whale lice being released from the broodpouch of the female. The amphipods have no free- swimming stage. Subsequent moultings pro- duce sexually mature adults. Other Reported Balaena inysticetus Parasites Nematode. — Crassicauda crassicauda is a nematode parasitizing the urogenital system and sometimes other parts of the body. Al- though the life cycle of C. crassicauda has not been determined, members of the order in which this genus belongs reproduce viviparously or ovoviparously and parasitize the body cavity, blood sinus, air bladder, or other tissues of aquatic vertebrates. Cope- pods are considered intermediate hosts for C. crassicauda. For cetaceans, the nematode has been reported from Tiirsiops truncatus (bottlenosed dolphin), Balaenoptera mus- culus (blue whale), Megaptera novaengjiae (humpback whale), Balaen mysticetus (bow- head whale), Ziphius cavirostris (Cuvier's beaked whale), Balaenoptera acutorostrata (minke whale), Balaenoptera horealis (sei whale), and Balaenoptera physalus (fin whale) (Dailey and Brownell 1972). Trematode. — Lecithodesmus goliath is a fluke that parasitizes bile ducts of Cetacea. Lecithodesmus goliath produces large eggs that are triangular in cross-section. MoUus- cans are intermediate hosts, and metacercar- iae can be ingested with the moUuscan inter- mediate host (Dailey and Brownell 1972). Small clams (bivalves), which are members of the phylum mollusca, have been reported from the colon of a bowhead whale (Lowry and Burns 1979). Acanthocephala. — Bolhosoma halaenae is an acanthocephalan that is found in the intestine of marine mammals including B. mysticetus (Dailev and Brownell 1972, Nei- land 1962). The parasites observed during this study and all those reported for the bowhead whale are listed in Table 3. The parasites reported for the bowhead whale are compared with those reported for two other cetaceans, the gray whale [Eschrichtus rohustus) and the blue whale {Balaenoptera ??i».scu/j/.s)(Table 4). Discussion Samples of bowhead whale tissue were sent to our laboratory during 1980 to be examined for parasites. From samples of five bowhead whales, two protozoans, four genera of di- atoms, and a nematode have been added to the existing list of parasites (Table 3). With additional samples, the hst would most likely be expanded, especially the protozoan forms. Data from this study confirmed the presence of Cyamus ceti, a whale louse, as well as the presence of an Ogmogaster, which had been described in a bowhead whale in 1979 (Shults 1979). Samples of blood from four whales were negative for parasites. Because of its currently known dietary habits, the bowhead whale is not subject to many of the internal parasites found in marine mammals that feed on fish, large crustaceans, and mollusks. Fish, large crustaceans, and mollusks are common intermediate hosts for helminths of marine mammals (Ridgway and Dailey 1972). The bases for placing the protozoan, found in the colon contents of one whale, in the family Endamoebidae are its small size and location, the presence of one to four nuclei per July 1987 Heckmann etal: Whale Parasites 367 Fig. 12. SEM of the ventral surface of the whale "louse," Cyamns ceti (8X). Cijamus ceti is not a louse but a highly modified amphipod infesting the skin of whales. The anterior (a) and posterior (p) parts of C. ceti are labeled. cyst, and numerous food vacuoles in the cyto- plasm. Members of the Endamoebidae are typically parasites or commensals of the diges- tive systems of arthropods and vertebrates (Schmidt and Roberts 1984). Species of Enta- moeba are common entocommensals and par- asites of the digestive system of vertebrate and invertebrate hosts. The present study is the first record of a protozoan parasite for the bowhead whale. Additional material must be 368 Great Basin Naturalist Vol. 47, No. 3 Table 3. A consolidated list of parasites for Balaena mysticetus, bowhead whale. Parasite Location in host Protozoa ♦Amoeba form Entamoeba sp. * Flagellate form Colon, small intestine Colon, small intestine Diatoms: (Plant) *Cocconeis *Stauroneis *Navicula *Gomphonema Skin, normal and eroded areas Acanthocephala **Bolhosoma balaenae Intestine Cestoda (Platyhelminthes) **Fhijllohothrium delphini Tissue (blubber) Trematoda (Platyhelminthes) *Ogmogaster plicatus **Lecithodesmtis goliath Intestine Bile ducts Nematoda *Anisakis-type larvae *Anisakid: Contracaecum or Anisakis **Crassicauda crassicauda Forestomach submucosa, encysted Stomach Intestine Amphipoda *Cijamus ceti Attached to baleen *Parasites observed during this study. ** Parasites not observed during this study, whale (Dailey and Brownell 1972). but reported for the bowhead collected from the colon oi Balaena mysticetus to determine the characteristics of this flagel- lated protozoan and its correct taxonomic status. Only three examples of the flagellate were observed from material taken during 1980. The ideal situation for examining tissue for parasites is to be "on site" when an animal is killed. The necessity for examining tissue from the brain and ear, which was not avail- able for this study, is due to the implication of two helminths in whale strandings (Stroud and Dailey 1978, Ridgway and Dailey 1972, Stroud and Roffe 1979). the trematode Na- sitrema infects the central nervous system, and a species of Stenurus, a nematode, has been found in the ears of cetaceans. The brains of stranded animals have shown para- sitically induced lesions caused by trematode (Nasitrema) eggs. Parasites may be a partial explanation for cetacean strandings (Beverly- Burton 1978). Presumably due to feeding habits of the host (Lowry and Burns 1980, Lowry and Frost 1984, Lowry et al. 1978), no adult tapeworms have been reported for the bowhead whale. Phyllobothrium delphini is a cestode larval stage (plerocercoid) found in the blubber of whales, usually around the anal orifice (Dailey and Brownell 1972). We did not find cestode plerocercoids in the samples of bowhead whale tissue sent to us for this study. Diatoms are common organisms attached to the skin of whales (Nemoto 1956). Numerous diatoms, single-celled plants containing sili- con walls, were observed infesting the skin of bowhead whales from 1980 skin samples. Four genera were identified in the present study. Diatoms were 5 to 10 times more nu- merous in the eroded areas of the host's skin than in noneroded areas; bacteria and proto- zoa were also found in the same erosions. The skin of cetacea is an important area for ther- moregulation (Ridgway 1972). Japanese work- ers consider diatoms to be parasitic on whale skin (Nemoto 1977, Omuro 1950). Once an opening is established in the outer surface of the skin, diatoms, bacteria, and protozoa (Figs. 13, 14) may become opportunists and use this area as a microhabitat. Excessive numbers of such opportunists appear to dam- age the skin. The nematode Anisakis is common in marine mammals (Dailey and Brownell 1972). Larval anisakids have been reported in the digestive tract of humans (anisakiasis), and in Europe and Japan there are records of this helminth as a possible cause of host death (Faust 1975, Schmidt and Roberts 1984). A limited number of cases of anisakiasis have been reported in North America (Myers 1979, Dailey et al. 1981). Fish samples sent to our laboratory from Alaska contained a larval an- isakid (Heckmann and Otto 1985). Including the results of the present study, two protozoans, four diatoms, two trematodes, one cestode, one acanthocepha- lan, two nematodes, and one amphipod (louse) represent the current list of parasites for the bowhead whale. Acknowledgments We thank the on-site tissue-collection team at Barrow, Alaska, under the direction of Dr. Thomas F. Albert, for assistance in collection of specimen material. We also thank James Allen and Connie Swenson, Brigham Young University Electron Optics Laboratory, who assisted with the SEM preparations. Dr. Jer- July 1987 Heckmann etal.: Whale Parasites 369 Table 4. Comparison of parasites observed in three species of baleen whales. Parasite group with listed species Baleen whale (host) Eschrichfiis robusttis O O O Gray whale Balaenoptera mtiscultis' O O O Blue whale Balaena mysticetus^ P P P Protozoa Acanthocephala Cestoda* Trematoda* Nematoda Amphipoda** EFD B1B2B3B4C P1P2P3T OiOoOaL AAiCiC.P C oooop oppo oppo 00000 O PPPPO OPOP PPOO POPOP P POOOO POOO PPOP OPPPO P O^Not observed P=Obsened in host *Phyluni: Plat\helminthes ** Phylum: Arthropoda ' 'Daile\ and Brownell 1972 *rhis study and Daile\- and Browniell 1972 Codes for parasites: Protozoa E =^ Amoeboid form [Entamodeba] F = Flagellate D - Diatoms; 4 species Acanthocephala Bi = Bolboscmm balaenae B2 - Bolbosoma brevicolle B3 = Bolbosonia hamiltoni B4 = Bolbosoma turbinella C = Corynosoma sp Cestoda Pi - Phyllobothrium detphuu Po ^ Pi'iapocephahis sp P3 ^ Pseudophyllidae sp. T ^ Tetrabothrius affinis Trematoda Oi - O^mogaster plicatus Oa^ Ogtnogaster antarcticus O3 ^ Ogmogaster pentcdineatus L ^ Lecithudesmus gotiath Nematoda A = Anisakis Ai = Anisakis-type larvae Ci = Crassicauda crassicauda C2 = Contracaecum sp. P = Porrocaecum decipiens Amphipoda C = Cyamus ceti roldT. Haldiman, Louisiana State University, provided Figures 3a, 5, and 14 for this report. This study was supported by Bureau of Land Management Contract AA851-CT0-22 to the University of Maryland, College Park, Mary- land. LiTER.\TURE Cited Albert. T F 1981. Listing of collected bowhead whale specimens with observations made during initial examination. Pages 84.5-916 in T. F. Albert, ed.. Tissue structural studies and other investigations on the biology of endangered whales in the Beau- fort Sea. Report to the Bureau of Land Manage- ment from the Department of Veterinar> Science, University of Maryland, College Park. 9.5.3 pp. Barnes, R D 1980. Pages 263-312 in Invertebrate zool- ogy. VV. B. Saunders Company, Philadelphia. Beverly-Burton. M 1978. Helminths of the alimentary tract from a stranded herd of the Atlantic white- sided dolphin, Lagenorhynchus acuttis. J. Fish Res. Board Canada: 35: 1356-13.59. Dailey. M D . AND R L Brownell 1972. A checklist of marine mammal parasites. Pages 528-589 in S. Ridgway, ed.. Mammals of the sea, biology and medicine. Charles C. Thomas Co. Dailey, M D , and W A Walker 1978. Parasitism as a factor (?) in single strandings of southern California cetaceans. J. Parasitol. 64: .593-.596. Dailey, M D , L Jensen, and B. Westerhof Hill 1981. Larval anisakine roundworms of marine fishes from southern and central California, with com- ments on public health significance. California Fish and Game 67: 240-245. Faust, E C . P. C. Beaver, and R. C. Jung. 1975. Animal agents and vectors of human disease. Lea and Febiger. Fuller. H J , and O Tippo 1960. College botany. Holt, Rinehart and Winston, Co. Hadidj.ma. P , E I Herry, H Mahfudin-Burhanuddin, AND M Hutomo 1978. Larvae of anisakidae in marine fish of coastal waters near Jakarta, Indone- sia. J. Trop. Med. and Hygiene 27: 51-.54. Haldiman, J. T., Y. Z. Abdelbaki, F K. Al-Bagdadi, D. W DuFFiELD, W. G. Henk, andR B. Henry 1981. Determination of the gross and microscopic struc- ture of the lung, kidney, brain and skin of the bowhead whale, Balaena mysticetus. Pages 305-662 in T. F. Albert, ed.. Tissue structural studies and other investigations on the biology of endangered whales in the Beaufort Sea. Report to the Bureau of Land Management from the De- partment of Veterinar}' Science, University of Maryland, College Park. 953 pp. Heckmann. R 1981. Parasitological study of the bowhead whale, Balaena mysticetus. Pages 27.5-.304 in T. F. Albert, ed. , Tissue structural studies and other investigations on the biology of endangered whales in the Beaufort Sea. Report to the Bureau of Land Management from the Department of Veterinary Science, University of Maryland, Col- lege Park. 9.53 pp. 370 Great Basin Naturalist Vol. 47, No. 3 Fig. 13. Micrographs representing the presence of: 13a, protozoa (P); 13b, bacteria (b); and 13c, diatoms (d) in the eroded areas of bowhead whale epidermis (1,000X). Heckmann, R. a., and T. Otto. 19S.5. Occurrence of an- Heckmann, R. A., R Warnock. and L Jensen 1980. Par- isakid larvae (Nematoda: Ascardidia) in fishes from asites (RU-979). Pages .517-.538 in]. Kelley and G. Alaska and Idaho. Great Basin Nat. 4.5: 427-431. Laursen, eds. , Investigation of the occurrence and July 1987 Heckmann et al.; Whale Parasites 371 Fig. 14. SEM micrograph of bowhead whale skin representing the t\pes of organisms, bacteria (b) and diatoms (d), that could invade erosions in the host epidermis (e). Note micron bar. beha\ ior patterns of whales in the vicinity of the Beaufort Sea lease area. Final Report to the Bu- reau of Land Management from the Naval Arctic Research Laboratory, Barrow, Alaska. Kudo, R. R. 1966. Pages 518-.564 in Protozoology. Charles C. Thomas, Springfield, Illinois. Leung, Y. 1967. An illustrated key to the species of whale- lice (Amphipoda, Cyamidae), ectoparasites of Cetacea, with a guide to the literature. Cruste- ceana 12; 279-291. Levine. N D , J O Corliss, F E G Cox. G Derou.x. J Crain. B M Honingberg. G F Leedale. A R LoEBLiCH III, J LoM, D. Lynn. E G Merinfeld. F C Page, G Poljanskv. \' Spr.\gue, J Vavr\, AND F G Wallace 1980. A newly re\ ised classifi- cation of Protozoa. J. Protozoolog>' 27: 37-58. Lowry, L. F., and J Burns 1979. Tissues, structure and function (RU 280g). Pages 437-447 in J. Kelley and G. Laursen, eds., In\estigation of the occur- rence and behavior patterns of whales in the vicin- ity of the Beaufort Sea lease area. Final Report to the Bureau of Land Management from the Naval Arctic Research Laboratory, Barrow, Alaska. Lowry. L. F., and J J Burns 1980. Foods utilized by bowhead whales near Barter Island, Alaska, autumn 1979. Marine Fisheries Review 42(9-10): 88-91. Lowry. L. F., and K J Frost 1984. Foods and feeding of bowhead whales in western and northern Alaska. Scientific Report. Whales Research Institute 35:1-16. Lowry, L F., K. J Frost, and J J Burns 1978. Food of ringed seals and bowhead whales near Point Bar- row, Alaska. Canadian Field-Naturalist 92: 67-70. Martin. W E , C K Haun. H S Barrow, and H Cr.\\toto. 1970. Nematode damage to brain of striped dolphin, Lagenorphijnchus ohliquidens . Trans. Amer. Microsc. Soc. 89: 200-205. Meyers. B J 1979. Anisakine nematodes in fresh com- mercial fish from waters along the Washington, Oregon and California coasts. J. Food Protection 42: .380-384. MiGAKi, G 1981. The microscopic examination of the bowhead whale, Balaena mijsticetus, and the gray whale, Eschrichtius robustus. for changes due to toxic substances and infectious agents. Pages 173-199 in T. F. Albert, ed.. Tissue structural studies and other investigations on the biology of endangered whales in the Beaufort Sea. Report to the Bureau of Land Management from the De- partment of Veterinary Science, LTniversity of Maryland, College Park. 953 pp. MiGAKi. G . R A Heckmann. and T F. Albert 1982. Gastric nodules caused b\ "anisakis type" larvae in the bowhead whale (Balaena inysticetus). J. Wildl. Dis. 18: 353-358. Neiland. K. 1962. Alaskan species of acanthocephalan genus Corynosoma Luche, 1904. J. Parasitol. 48(1): 69-76. Nemoto. T 1956. On the diatoms of the skin film of whales in the Northern Pacific. Sci. Rep. Whales Res. Inst. 11:99-1.32. 372 Great Basin Naturalist Vol. 47, No. 3 Nemoto. T., F L Brownell, Jr . andT. Isfiimaru 1977. Cocconeis diatoms on the skin oiFranciscana. Sci. Rep. Whales Res. Inst. 29: 101-105. Olsen, O. W. 1974. Animal parasites, their hfe cycles and ecology. University Park Press. Omura. H. 19.50. Diatom infection on blue and fin whales in the antarctic whaling area V (the Ross Sea area). Sci. Rep. Whales Res. Inst. 4: 14-26. Oshima, T. 1972. Anisakis and anisakiasis in Japan and adjacent area. Pages .301-.39.3 in K. Morishita, Y. Komuja, and H. Matsubayashi, eds.. Progress of medical parasitology in Japan. Vol. IV. Megura Parasitological Museum, Tokyo. Rausch, R L, and F H Fay 1966. Studies on the helminth fauna of Alaska. XLIV. Revision of Og- mogfl.sfer Jagerskiold, 1891, with a description of O. pentalmeatus sp. n. (Trematoda: Notocotyli- dae). J. Parasitol. .52; 26-38. Rausch. R L.. and D W Rice 1970. O^mogaster trilin- eatus sp. n. (Trematoda; Notocotylidae). Proc. Helm. Soc. Washington 37; 196-200. RiDGW.w, S. H. 1972. Homeostasis in the aquatic environ- ment. Pages 590-747 in S. Ridgway, ed.. Mam- mals of the sea, biology and medicine. Charles C. Thomas Co. Ridgway. S. H.. and M, D. Dailey. 1972. Cerebral and cerebellar involvement of trematode parasites in dolphins and their possible role in stranding. J. Wildl. Dis. 8; 33-43. Schmidt, J D., and L. S Roberts 1984. Page 492 in Foundations of parasitology. C. V. MosbyCo., St. Louis. ShirakiT 1974. Larval nematodes of the family anisaki- dae (Menatoda) in the northern Sea of Japan — as a causative agent of eosinophilic phegmone or gran- uloma in the gastro-intestinal tract. Acta Medicaet Biologia 22; 57-98. Shults, L M 1979. Og,mogaster antarcticus Johnston, 1931 (Trematoda; Notocotylidae) from the bow- head whale, Balaena mysticetus L., at Barrow, Alaska. Canadian J. Zool. 57; 1.347-1348. Smith. J W 1971. Thysanoessa inerinis and T. longicau- data (Euphausiidae) as first intermediate hosts of Anisakis sp. (Nematoda; Ascaridata) in the North Sea, to the north of Scotland and at Faroe. Nature 2.34: 478. Smith, J W , and R Wootten 1978. Anisakis and An- isakiasis. Pages 93-163 in W. H. R. Lumsden, R. Muller, and J. R. Baker, eds., Advances in para- sitology (16). Stroud, R K , and M D Dailey 1978. Parasites and associated pathologv in pinnipeds stranded along the Oregon coast. J.' Wildl. Dis. 14: 292-298. Stroud, R K , andT J Roffe 1979. Causes of death in marine mammals stranded along the Oregon coast. J. Wildl. Dis, 15:91-97. Wootten, R 1978, The occurrence of larval anisakid nematodes in small gadoids from Scottish waters. J. Mar. Biol. Ass. U.K. .58; 347-3.56. Wootten, R , and I F. Waddell 1977. The occurrence of larval nematodes in the musculature of cod and whiting from Scottish waters. J. du Conseil. Int. E.xplor. Mer. 37: 266-273. YoKOGAWA, M , AND H YosHiMUR.\ 1967. Clinicopatho- logical studies on larval anisakiasis in Japan. Amer. J. Trop. Med. Hyg. 16; 723-728. REPRODUCTION OF THE PRAIRIE SKINK, EUMECES SEPTENTRIONALIS, IN NEBRASKA Louis A. Soinma Abstract — Clutch sizes of the prairie skink, Eumeces septciitrioiialis, in Nebraska are positively correlated with female snout-vent lengths (SV'Ls). Data presented in this study and others indicate Nebraska populations of E. septentrioiialis have larger average clutch sizes than other populations within this species' range. The prairie skink, Eumeces septentrionalis, is a semi-fossorial, oviparous lizard inhabiting the central lowland province region and tall- grass prairies of North America (Breckenridge 1943, Nelson 1963). In Nebraska, E. septcn- trionolis is found primarily in tall-grass prairies (Lynch 1985) and urban habitat (Somma 1985a). Few reproductive data exist for Nebraska populations (Gehlbach and Col- lette 1959, Iverson 1976, Somma 1985b). This study summarizes data on clutch size and SVL of 21 captive female E. septentrionalis col- lected in eastern Nebraska. Eighteen gravid females from Douglas County and three from Pawnee County were collected in May 1984 and placed in separate plastic terraria containing a moist soil sub- strate. Each terrarium contained a 15 x 15- cm acrylic plate under which the skinks could oviposite. The skinks were fed crickets and mealworms ad libitum. A 14L:10D photo- period was maintained for the duration of the study. Oviposition occurred between 18 and 30 June, and the eggs were brooded by the fe- males. Measurements of initial egg dimen- sions were obtained for each clutch (Table 1). An egg that was removed from one clutch immediately upon oviposition contained an embryo in an advanced stage (32-33) of devel- opment (Dufaure and Hubert 1961). One fe- male died before ovipositing and was found to contain 7 oviducal eggs that were included in the analysis. The mean clutch size was 10.95 ± 0.85 eggs (range - 4-18). A linear regres- sion (Sokal and Rohlf 1981) indicates that clutch size has a highly significant positive Table 1. Female SVL, clutch size, and mean egg di- mension for Eumeces septentrionalis. SVL Clutch Mean egg dimension (cm) size (length X diameter cm) 7.88 18 1.26 X 0.81 6.96 7 1.31 X 0.86 7.42 11 1.27 X 0.76 6.96 13 1.15x0.69 6.30 4 ** 6.74 7* ** 7.48 11 1.08 X 0.72 6.77 4 1.21 X 0.72 6.64 6 1.18x0.74 8.00 13 1.20x0.71 7.14 11 1.32 X 0.85 6.96 8 1.23 X 0.80 7.28 12 1.19x0.74 7.98 17 1.05 X 0.71 8.04 17 1.14x0.81 7.38 11 1.09 X 0.76 6.96 13 1.21 X 0.73 7.48 11 1.04 X 0.82 6.82 11 1.05 X 0.77 7.50 13 1.04 X 0.78 7.32 12 ** *oviducal egg count **not obtained correlation with female SVL (Fig. 1, r^ = 0.706, P < .0001). Clutch sizes for other pop- ulations of Eitmeces septentrionalis are as fol- lows: Minnesota, x -^ 8.79, N =^ 19 (Brecken- ridge 1943), X = 6.60, N - 9 (Nelson 1963); Wisconsin, 4-6, N - 3(Vogt 1981); Nebraska, X - 14.5, N = 2 (Gehlbach and Collette 1959), X - 14.0, N - 5 (Iverson 1976), x - 14.7, N = 3 (Somma 1985b); Kansas, x = 8.00, N = 4 (Clarke 1955); Texas, 9, N - 1 (Smith and Slater 1949), 9, N - 1 (Sabath and Worthing- ton 1959). Department of Biolog\ , University of Nebraska at Omaha, Omaha Gainesville, Florida 32611. Nebraska 68182 Present address Department of Zoology, University of Florida, 373 374 Great Basin Naturalist Vol. 47, No. 3 18 17 16 15 14 13 12 UJ 11 N 55 1° y =6.79x -38.20 r'zO.TOe 8 7 6 5 - 4 - 3 - 2 6.0 6.5 7.0 7.5 8.0 FEMALE SNOUT-VENT LENGTH (CM) Fig. 1. Regression plot of clutch size vs. female S\'L for Eumeces septenfrionalis. Fitch (1985) has summarized chitch size data for Eumeces septentrionalis using previ- ously published data. Populations were de- scribed as "northern (Breckenridge 1943) or "southern" (Clarke 1955, Gehlbach and Col- lette 1959, Sabath and Worthington 1959, Iverson 1976) and were combined to obtain a mean for "northern" populations and another larger mean representing "southern popula- tions (Fitch 1985). These data were used to illustrate a north-south trend in increasing clutch size within this lizard s range. Listing Nebraska and Kansas populations as south- ern, however, is inappropriate and results in an unnaturally large mean. Earlier studies suggesting that Nebraska populations of E. septentrionalis have larger clutch sizes than others to the northern and southern ends oi its range (Gehlbach and Collette 1959, Iverson 1976) are supported by this study. Mean clutch sizes in these previous studies, how- ever, could have been exaggerated by the limited sample sizes. Larger samples ob- tained from other populations throughout this species range, along with corresponding SVL data, would greatly facilitate comparisons of reproductive data. Acknowledgments I thank J. D. Fawcett, T. Cherney, M. Cherney, F. Kock, J. Lokke, J. O'Hare, R. Vaughn, L. Ward, and S. Wurster for assist- ing with this study. I also thank J. D. Fawcett for his guidance and encouragement. These data were part of a master's thesis presented to the Department of Biology, University of Nebraska at Omaha. The Department of Biol- ogy provided funding for this study. Literature Cited Breckenridce. W J 194.3. The life history of the black- baiided skink Eumeces septentrionalis septentri- onalis {hMrd). Amer. Midi. Nat. 29: .591-606. Clarke. R F 19.55. Observations on Eumeces s. septen- trionalis in Kansas. Herpetologica II: 159-164. DuF.\URE, J P . .'\ndJ Hubert 1961. Table de developpe- nient dn lezard vivipare: Lacerta (Zootoca) livipara Jacquin. Arch. Anat. Micro. Morph. Exp. (Paris) 50: 309-328. Fitch, H S 1985. Variation in clutch and litter size in New World reptiles. Univ. Kansas Misc. Publ. Mus. Nat. Hist. (78): 1-76. Gehlbach, F R , and B B. Collette. 1959. Distribu- tional and biological notes on the Nebraska her- petofauna. Herpetologica 15: 141-143. Iverson, J B 1976. Notes on Nebraska reptiles. Trans. Kansas Acad. Sci. 77: 51-62. Lynch, J D 1985. Annotated checklist of the amphibians and reptiles of Nebraska. Trans. Nebraska Acad. Sci. 13: .33-57. Nelson, W F 1963. Natural histor\ of the northern prairie skink, Eumeces septentrionalis septentri- onalis (Bair.d). Lhipublished dissertation. Univer- sity of Minnesota, Minneapolis. Sabath, M , and R Worthington 19.59. Eggs and young of certain Te.xas reptiles. Herpetologica 15: 31-34. Smith, H M., and J A Sl.\ter. 1949. The southern races oi Eumeces septentrionalis (BAird). Trans. Kansas Acad. Sci. .52: 438-448. Sokal, R. R , AND F J ROHLF 1981. Biometry. W. H. Freeman and Co., San Francisco. SoMMA, L A 1985a. Brooding beha\ior of the northern prairie skink, Eumeces septentrionalis septentri- onalis (Baird), and its relationship to the h\dric en\ironment of the nest substrate. Unpublished thesis. University of Nebraska at Omaha. 1985b. Notes on maternal behavior and post-brood- ing aggression in the prairie skink, Eumeces septentri- onalis. Nebraska Herpetol. Newsl. 6: 9-12. Vogt, R C 1981. Natural history of amphibians and rep- tiles in Wisconsin. Milwaukee Public Museum, Milwaukee. LIST OF IDAHO SCOLYTIDAE (COLEOPTERA) AND NOTES ON NEW RECORDS' Makolin M. Fiirniss" and James B. Johnson' Abstract — Reported are 105 species of Scolytidae (Coleoptera) from Idaho. About one-third of these are rarely collected, of which 22 species are known from a single locality each. Twelve species reported from Idaho for the first time are; Carphobonis carri Swaine, C. sansoni Swaine, Phloeosinus huferi Blackman, Conophthorus monophyllae Hopkins, Dnjocoetes hetulae Hopkins, Ips confusus (LeConte), Pitijopiitlwrus absonus Blackman, P. aqtiilus Black- man, P. blandus Blackman, P. dclctus LeConte, P. sculptor Blackman, and Xyleboiinus saxeseni (Ratzeburg). Significant extensions of the known distributions in Idaho are reported for seven other scoKtids; Alnipha^iis aspericol- lis (LeConte), Dendroctonus murraijanac Hopkins, Phloeotribtis lecontei Schedl, Procnjphalus mucronatus (LeConte), Trypophloeus populi Hopkins, Xylcbonis dispar {Fahricius), andX. intnisus Blandford. Xyleborus dispar especially needs study in anticipation that it may become increasingK important in Idaho fruit trees and other woody plants including ornamentals and shade trees. Idaho has an abundance of trees and shrubs that can serve as scolytid hosts, but the scolytids of Idaho have not been surveyed systematically to determine the total number of species, their specific hosts, and their dis- tributions within the state. Such information is fundamental to the orderly development of the natural history of this region and will facili- tate scolytid research. For example, the genus Dendroctonus contains several of our most abundant and destructive species (e.g., D. ponderosae Hopkins) and one of the least abundant and least destructive (D. mur- rayanae Hopkins). By knowing where D. murraijanac occurs, it can be studied and the circumstances that keep it from becoming abimdant may prove important in managing species that are sometimes damaging. Since 1984 we have compiled a comprehen- sive list of Idaho scolytids from literature, mu- seum specimens, and our own field collec- tions. This task was stimulated by the recent availabilitv of the works of R. L. Furniss and V. M. Carolin (1977), D. E. Bright, Jr. (1981), and, especially, S. L. Wood's monograph on North American bark and ambrosia beetles (1982). Twenty-two Idaho species are represented by only single specimens or localities. Addi- tional species doubtless occur in Idaho but have not yet been found or reported, and some exotic species may find their way here in the future, either to settle quietly into their new niches or to attain importance in orna- mentals, fruit trees, or forests. So, the list will likely change as our work continues. Besides the list of 105 species and their abundance, we present notes on 12 species reported from Idaho for the first time and major range extensions within Idaho for 7 other species. All measurements of host mate- rial are in metric units, including distances from landmarks, although the latter are in- variably in miles on labels of pinned museum specimens. Names of collectors are given as per labels or as stated in the literature. The numbers of known pinned adult specimens follow the collection data. Specimens de- posited in the University of Idaho, William F. Barr Entomological Museum, are designated UI-WFBM. Known repositories of others are abbreviated as follows: SLW -^ S. L. Wood Collection, Brigham Young University, Provo, Utah; WSU = Washington State Uni- versity, Pullman, Washington; CNC = Cana- dian National Collection, Ottawa, Ontario, Canada. In other cases, we cite the literature from which we acquired the record. Species Newto Idaho Subfamily Hylesininae Carphoborus carri Swaine University of Idaho Agricultural Experiment Station Research Paper No 873.3 "Department of Plant, Soil and Entomological Sciences, University of Idaho, Moscow, Idaho 83843. 375 376 Great Basin Naturalist Vol. 47, No. 3 Type LOCALITY: Edmonton, Alta., Canada. Biology: Unstudied. Polygynous; breeds in relatively dry, dead bark of boles of small, suppressed spruces and unthrifty, lower branches of living trees. Galleries deeply score the wood (Wood 1982). Distribution AND NOTES: CANADA: Alta., Man., New Brun., NWT, Yuk.; USA: Alas., Mont., S. Dak., Wyo., IDAHO: North shore of Henrys Lake, Fremont Co., 21-VII-1985, Picea glauca, M. M. Furniss and J. B. Johnson (19 9, 17 d UI-WFBM). A southernmost popula- tion of white spruce, Plcea glauca (Moench) Voss, grows on boggy ground along the north shore of Henrys Lake. The trees may be hy- brids of white and Engelmann spruce. Five C. carri new adults were taken from a lower branch of a recently dead, standing tree that was 50 cm diameter and 37 m tall. Carphobonis sansoni Swaine Type locality: Banff, Alta. , Canada. Biol- ogy: Unstudied. Polygynous; breeds in bark of the bole of unthrifty, suppressed seedlings and in unthrifty, shaded-out branches of large, living, standing trees (Wood 1982). Dis- tribution AND NOTES: CANADA: Alta.; USA: Colo., Ore., Ut., Wyo., IDAHO: Emigration Campground, 24 km W of Montpelier, Bear Lake Co., 24-VII-1984, Picea engehnannii, M. M. Furniss and J. B. Johnson. (1 UI- WFBM). Collected from a shaded-out limb on a wind-thrown tree. Phloeosinus hoferi Blackman Type locality: Ute Pass, Colo. BiologY: Unstudied. Monogynous. Infests bark of small branches and twigs of dying trees (Wood 1982). Distribution and notes: CANADA: B.C.; USA: Ariz., Calif., Colo., Nev., N.M., N.Dak., S.Dak., Tex., Ut., Wyo., IDAHO: Two km N of Almo, Cassia Co., 25-VII-1984, Juniperus osteosperma, M. M. Furniss and J. B. Johnson (1 UI-WFBM). Reared from a 23-cm-diameter felled, limbed tree; probably emerged from branches 2-10 cm diameter. At time of collection (25-VII-1984), mature larvae and pupae were present, but these may have been exclusively P. serratus LeConte, a larger species that was abundant, especially in the trunk. Subfamily Scolytinae Conophthorus monophijUae Hopkins Type locality': Ventura Co., Calif. Biol- ogy: Unstudied. In other studied species, the female bores into the cone base in spring at the beginning of the second year of cone growth. The egg gallery extends the length of the cone center. Progeny mature during that summer within the cone and generally over- winter there, although in the case of C. pon- derosae Hopkins (^ C. lamhertianae Hop- kins), some adults emerge in the fall and overwinter in the tips of live twigs (R. L. Furniss and V. M. Carolin 1977). DISTRIBU- TION and NOTES: Calif., Nev., Ut., IDAHO: City of Rocks, Cassia Co., 25-VII-1984, Pinus monophi/Ua cones, M. M. Furniss and J. B. Johnson' (12 UI-WBFM, 5 SLW). Attacked cones common, most contained a single beetle, mired and dead in profuse resin ex- uded from entrance located at base of cone (i.e., often unsuccessful). Dryocoetes betidae Hopkins Type LOCALiri': Grant Co., Va. Biology: Unstudied. Polygynous. It infests bark of stumps and the bole and limbs of recently cut and unthrifty trees (Wood 1982). Distribu- tion AND NOTES: CANADA: Alta., B.C., Newf., N.B., Ont., Que.; USA: D.C., Fla., La., Me., Mich., Miss., Mont., N.H., N.J., N.Y., Calif., Penn., Va., V.I., Vt., W.Va., Wash., IDAHO: Reeder Bay, Priest Lake, Bonner Co., 6-VIII-1985, Betida papyrifera, M. M. Furniss, J. B. Johnson, and S. J. Cast (13 UI-WFBM). Parents, larvae, and one pupa in phloem of the trunk of a 46-cm-diame- ter tree toppled by snow in previous winter. Sporadic infestation also noted in 15-cm-di- ameter basal portion of a tree that had broken off at 3 m height. Ips confusus (LeConte) Type locality: Southern Calif. BiologY: Polygynous. Three to four generations per year reported in southwestern states (fewer likely in Idaho). Adults may overwinter en masse under bark of main stem, thoroughly scoring the wood surface (Chansler 1964). Distribution and noteS: MEXICO: Baja Calif., Chih.; USA: Ariz., Calif., Colo., Nev., N.M., Ut., Tex., (Wyo.), IDAHO: City of Rocks, Cassia Co., Pinus monophylla, 14-VI- July 1987 FURNISS, JOHNSON: IDAHO SCOLVTIDAE 377 1968, W. F. Ban- (2 UI-WFBM); same local- ity, 25-VII-1984, M. M. Furniss and J. B. Johnson (4 UI-WFBM, 3 SLW). Mainly ten- eral, but some darkened, adults in base of a dead 23-cm-diameter standing tree with bright orange foliage. Some Pityophthonis in- termingled; Dendroctoniis valens LeConte and Hylurgops porosus LeConte below. Pityophthonis absomis Blackman Type locality: Mineral King, Calif. BIOL- OGY: Unstudied. Polygynous. Reported fairly common at high elevation (Bright 1981) and infesting small branches and in shaded-out small trees (Wood 1982). Distribution and NOTES: CANADA: Alta., B.C.; USA: Calif., Colo., Mont., Nev., Ut., IDAHO: 16 km E of Wayan, Caribou Co., 21-VII-1984, Abies hi- siocorpa, M. M. Furniss and ]. B. Johnson (9 UI-WFBM, 2 CNC). Attacking shaded-out, 1-2-cm-diameter branches. Eight km S of Old Williamsburg, Caribou Co., 22-VII-I9S4, Abies lasiocarpa, M. M. Furniss and J. B. Johnson (1 UI-WFBM, CNC). Reared from larvae infesting green 0.5-3.5-cm-diameter branches on ground. Six km E of Bostetler Guard Station, Cassia Co., 26-VII-1985, Abies lasiocarpa, M. M. Furniss and J. B. Johnson (1 UI-WFBM). Parent beetles from current-year attacks in 0.8-2.0-cm-diameter branches of 30-cm-basal-diameter dead tree with red foliage. Salmon Mtn., Idaho Co., 18-^11-1985, Abies lasiocarpa, M. M. Furniss and J. B. Johnson (8 UI-WFBM). Top-killed, 10-cm-diameter, 5-m-tall tree. Pityophthonis aqiiiliis Blackman Type localit\': Kaibab National Forest, Ariz. BIOLOGY: Polygynous. Infests lateral branches of lodgepole pine in association with the weevil, Pissodes terminalis Hopping (Colo.). Attack and emergence occur in mid- summer (Bright 1981). Distribution and NOTES: CANADA: Alta., B.C., Sask; USA: Ariz., Calif., Colo., Mont., N.M., S.Dak., Ut., Wyo., IDAHO: 6 km E of Bostetler Guard Station, Cassia Co., 26-VII-1985, Pi- nus contorta, M. M. Furniss and J. B. John- son (5 UI-WFBM, 1 CNC). Adults common in current-year egg galleries in 0.8-2.0-cm-di- ameter branches on a 30-cm-diameter dead, standing tree with red foliage. Pityophthonis hlandus Blackman Type locality: Argus Mountains, Calif. BI- OLOGY: Unstudied. Polygynous. Specimens collected from 3-8-cm-diameter branches and tree tops (Wood 1982). Distribution: USA: Ariz., Calif., Colo., Nev., Ut., IDAHO: City of Rocks, Cassia Co., 25-VII-1985, Pimis monophylla, M. M. Furniss and J. B. Johnson (10 UI-WFBM, 4 CNC). Pityophthonis deletus LeConte Type locality: Veta Pass, Colo. BiologY: Unstudied. Polygynous. The species is ex- tremely variable and as defined may include more than one species or subspecies (Bright 1981). Distribution and notes: MEXICO: Coah., Dgo.; USA: Ariz., Colo., N.M., S.C, Tex., Ut., Wyo., IDAHO: 23 km N of Mont- pelier. Bear Lake Co., 23-\TI-1984, Pinus flexilis, M. M. Furniss and J. B. Johnson (1 UI-WFBM). Infesting 0.5-1. 0-cm-diameter, shaded-out lower branches. City of Rocks, Cassia Co., 24-VII-1985, Pimis monophylla, M. M. Furniss and J. B. Johnson (1 UI- WFBM). Parents, larvae, and teneral adults in 0.4-1. 0-cm-diameter twigs with red foliage on live tree. Thirteen km E of Bostetler Guard Station, Cassia Co., 25-VII-1985, Pinus con- torta, M. M. Furniss and J. B. Johnson (4 UI-WFBM). In long tunnels running length- wise in 2-3-mm-diameter twigs with red fo- liage, killed by mistletoe. Pityophthorus scalptor Blackman Type LOCALiri': Julian, Calif. BiologY: Un- studied. Polvgvnous. Distribution and NOTES: CANADA: B.C.; USA: Calif., IDAHO: Plummer, Benewah Co., 28-IV- 1985, Pinus ponderosa, M. M. Furniss (2 UI- WFBM). From a shaded-out branch with red foliage on a small, live tree. Xyleborinus saxesini (Ratzeburg) Type locality': Europe. BiologY; The fol- lowing is based on Schedl (1962) and Batra (1963). The dwarfed males are flightless and apparently mate with their brood sisters, al- though outcrossing may occur rarely when tunnels intersect (or more commonly when males wander from one tunnel entrance to another [S. L. Wood, personal communica- tion]). Male/female ratios range from 1:7 to 1:39. Females construct a 1-mm-diameter, 378 Great Basin Naturalist Vol. 47, No. 3 3-5-cni-long tunnel radially into stems and large branches of dying or fallen trees. An enlarged cavity (brood chamber) is con- structed upward and downward at the end of the tunnel, in which eggs are laid one per niche. Up to 100 eggs are laid per female in groups of 5- 12. Larvae feed conimunalh', evi- dently on the yellowish fungus Ambrosiella sulfurea Batra (Batra 1967) which covers the wall of the brood chamber. Distribution and NOTES EUROPE, ASIA, AUSTRALIA, AR- GENTINA, BRAZIL, CHILE; CANADA: B.C., Ont.; USA: Ala., Ariz., Ark., Calif., Conn., Del., Fla., Ga., 111., Ind., la., Kan., Ky., La., Me., Md., Mass., Mich., Miss., Mont., N.H., N.J., N.Y., N.C., Ohio, Ore., Penn., S.C, Tenn., Tex., Ut., Va., Wash., IDAHO: Smith Creek, Boundary Co., 8-VI- 19S6, Popidus tremuloides, M. M. Furniss and J. B. Johnson (1 9 UI-VVFBM). Collected from a larval cradle of a Tnjpodcndron re- tusum (LeConte) gallery in a 20-cm-diameter, fire-scorched, recently fallen aspen. Extensions of Known Geographic Occur- rence IN Idaho Subfamily Hylesininae Alniphagus aspericoUis (LeConte) Type locality; Evidently Santa Barbara, Calif BIOLOGY; Monogynous. Bivoltine (B.C.); damaged or decadent trees are at- tacked by the respective generation in May and during July to early August. The typical galleries are unbranched and extend about 8 cm (2.0-4.5 cm in Idaho), parallel with the stem. Only stems of about 10-cm diameter and larger are usually infested. Susceptible phloem is usually restricted to a narrow zone in dying trees, between the lower, living stem and the dead distal portion. Several succes- sive generations may infest a stem before it is completely killed (JBordon 1969). Distribu- tion AND NOTES: CANADA: B.C., USA: Alas., Wash., Ore., Calif., Ut., IDAHO: Webb, Nez Perce Co., 4-X-1951, W. F. Barr (5 UI- WFBM). Povertv Flat, Krassel Ranger Dis- trict, Vallev Co., 23-IV-1959, Alniis sp., M. M. Furniss (3 UI-WFBM). Deary, Latah Co., l-X-1963, Alnus sp., M. M. Furniss (2 UI-WFBM). Falls Ranger Station, Bonner Co., 29-VI-1967, Alnus sp., M. M. Furniss (1 UI-WFBM). Orofino, Clearwater Co., 15-III- 1983, Alnus sp., B. J. Bentz and M. M. Furniss (5 UI-WFBM). Fiftv-seven km S of Salmon, Lemhi Co., 19-VIl'-1985, Alnus in- cana, M. M. Furniss and J. B. Johnson (21 UI-WFBM). Infesting a 12-cm-diameter stem; larvae and pupae present. Two km W of Elba, Cassia Co., 25-VII-1985, Alnus sp., M. M. Furniss and J. B. Johnson (4 UI- WFBM). New attacks with only one adult in each; sparse exit holes distally on stem from earlier infestation; larvae (some small) and pu- pae in older attacks; galleries in this stem were entirely in bark and did not etch the wood. Priest Lake Ranger Station, Bonner Co., 7- VII-1985, Alnus sp., M. M. Furniss, J. B. Johnson, and S. J. Cast (4 UI-WFBM). At- tacking adults onlv, including one to two per attack site. Moose Cr., 8 km WNW of Bovill, Latah Co., 21-VIII-1985, Alnus sp., M. M. Furniss and S. J. Cast (6 UI-WFBM). Three km N of Pinehurst, Valley Co., 10-III-1986, Bctida occidentalism M. M. Furniss (3 9, 2 d UI-WFBM). Pairs of beetles in new galleries in green phloem in the base of a25-cm-diame- ter, progressively dying tree. First record in other than alder. Spread Creek, 6.5 km N of Hwy 2, Boundary Co. , 9-VII-1986, Alnus sp. , M. M. Furniss and J. B. Johnson (4 UI- WFBM). Taken from base of a 15-cm-diame- ter dead, leafless alder also containing larvae. Dcndroctonus murrayanoc Hopkins Type locality; Keystone, Wyo. BiologY: Monogynous. Not comprehensively studied. Attacks are restricted to the lower bole near ground; galleries extend 12-20 cm downward to below ground. In Utah, first attacks oc- curred in the second week of July; eggs were present from 12 July to 9 Sept. , laid in groups of 20 to 50 or more. Larvae mine in congress. One and perhaps a partial second generation per year occur in Utah (Wood 1982). Distri- bution AND NOTES; CANADA: Alta., B.C., Man., Out.; USA: Colo., Mich., Minn., Mont., Ut., Wvo., IDAHO: (The only pub- lished record is "Targhee N. F." [Wood 1982], but we have been unable to locate any so- labeled specimens.) Five km SW of Bannock Pass, Lemhi Co., 18-19-VII-1984, Pinus con- toiia, M. M. Furniss and J. B. Johnson (9 9, 12 6 UI-WFBM). Five D. munayanac gal- leries, containing 1 dead and 5 live parents, were in the base of a 30-cm-diameter, lightning-struck tree. Two examined galleries July 1987 FURMSS, JOHNSON: IDAHO SCOLYTIDAE 379 had 7 and 23 larvae, probabK' in their 3rd instar, aligned en masse, side by side in a rather resinous chamber. Associated insects were: Hi/hir' 1958, Her petologica,' 13:267-271. 27 mi S Parral, Chihuahua. 1 (BYU 15652). 10 mi W Gomez Palacio, Durango, 3 (BYU 40064-6). 25 mi S Gomez Palacio, 1 (BYU 40115). 6 mi NE Pedriceno Highway 49, 3 (BYU 36236-8). 25 mi S Torreon Highway 49, 1 (BYU ,36240). 140 mi S Torreon Highway 49, 1 (BYU 36241). Specimens from near the type locality have dorsals 35-37; the one from Chihuahua 34 and the one 140 mi S Torreon only 30. Both are intergrades between pohjlepis and macrolepis, and in both cases the specimens are near the area of distribution for macrolepis. The data now available suggest that the subspecies pohjlepis is restricted to the low plains extending from southeastern Chihuahua to niortheastern Dmango. This distribution also suggests that it may occur in adjoining Coahuila. The largest adults (40064, S Gomez Palacio and 36240, S Torreon) have S-V length of 82 and 83 mm. If these size data and those pre- sented by Smith and Chrapliwy (1958) are representative of the populations of this sub- species, then it is indeed a small representa- tive of the species. Sceloporus poinsettii robi-wni. subsp. n. HoLOTYPE. — BYU Bean Mus. Nat. Hist. 14287, adult male, Cuiteco, Chihuahua, col- lected 19 July 1958, by W. W. Tanner and W. G. Robison. Paratopes.— BYU 14273-5, 14288-9 topo- tvpes; BYU 14602, 15667-9, 15670, Ceroc- ahui; BYU 17070-2, along road 4-8 mi SE Maguarichic. Diagnosis. — A southwestern Chihuahua subspecies of poin.settii with reduced femoral pores, 85% with 20 or less, compared to July 1987 TANNER: Lizards and Turtles of Chihuahua Table 2. Variation in three head scale patterns. 399 Subspecies No. Nasal to lorilabials percent Labiomentals to mental percent Median scale anterior to interpari( percent ?tal 82- 101- 7J 85- 85- \dult size poinsettii macrolepis polylepis robisoni Intergrades 17 14 9 14 59 west 90 J, east 44 '^ 65 90 90 85.5 12 7 0 50 20 100 38 90 57 90 -120 mm -117 mm J-99 mm -113 mm -115 mm 75-100% with 20 or more in other subspecies; dorsals low, 29-32; postmentals not in contact with infi-alabials; and adults large, 110-115 mm S-V. Description of t\'pe. — A young adult male, S-V 88.5 mm, total length 175 mm, dorsals 29, ventrals 47, scale rows 37, femoral pores 7-7; head scalation much as in S. p. poinsettii, most patterns variable, two rows of supraoculars, lorilabials contact nasal on one side; labiomentals contact mental; postmen- tals not in contact with infralabials; anterior dorsals, two parietals, and four enlarged scales surround the interparietal. Black collar 3 scales across medially, edged anteriorly by 2 scales of cream color and edged posteriorly by one light scale row, dorsum of body not distinctly barred; tail with 6 distinct rings; lateral belly blue patches edged medi- ally with darker blue, sides of throat and chin suffused with light blue, separated medially by a lighter area. Variation. — The subspecies of Sceloponts poinsettii, as noted in TalDle 1, are variable in the numbers of dorsal scales and femoral pores. Most noticeable is the consistently low number of pores of robisoni. Of the type se- ries (14), only 2 specimens have a total of 21, 3 have 20, and 9 less than 20. In the dorsal head scales there is little uniformity, except that in all poinsettii subspecies the frontal is widely separated from interparietal, either by one or several small scales or by enlarged scales ex- tending anterior from the parietals to the su- ture anterior to the interparietal. Table 2 sum- marizes the variation observed in three head scale patterns. Smith and Chrapliw>' (1958) referred to the relationship of the labiomen- tal to the mental, frontal to interparietal, and size of adults. Aside from the fact that macrolepis has larger and fewer dorsals and polylepis has smaller and more dorsals than other subspecies or populations examined, the relationships illustrated in Table 2 indi- cate additional differences not presented in the original description. In p. polylepis the labiomentals do not contact the mental and in size the adults (5), except for one, were less than 90 mm in S-V. They are more slender and less robust than other subspecies. These data strongly suggest that Sceloporus poinset- tii is undergoing differential environmental pressures from its desert to foothill to moun- tain habitats and thus may represent a rapidly evolving species. Sceloporus jarrovii jarrovii Cope Sceloporus jarroviijarrovii Cope, 187.5b, U.S. Geologi- cal and Geographical Surveys, W 100th Meridian 5;569. Colonia Garcia, 4 (BYU 2956, 1328-30). 25 mi from Colonia Juarez on road to Tres Rios, 13 (BYU 1.5440-1, 15599-600, 1.5792, 1.5811, and 7 mature embryos 32578-84). Black Canvon, west of Chuhuichupa, 11 (BYU 142767-82, 37632-35). 3 mi N Chuhuichupa, 21 (BYU 13903-7, 1.3935-6, 15413-14, 15416-23,1.5469-72). Meadow Valley, 2 (BYU 15716, 1,5743). North end of Blues Mountain-Gavilancito Sawmill, 2 (BYU 1.3596 and 15709). Rio Chico, 3 (BYU 15754-6). Cuesta el Toro, 5 mi S Gomez Farias, 2 (BYU 157894-5). 4 mi SE Creel, 12 (BYU 14.520-21, 1,5587-96). 1 mi NE Bocoyna, 3 (BYU 15476-8). Cerocahui, 12 (BYU 14597-601, 15474, 15645-7, l,5671-,3). Cuiteco, 10 (BYU 14270-2, 14290-3, 15657-8, 1.5664). 10 mi SW San Juanito, 7 (BYU 1,5796-802). 1 mi W La Lanja, 4 (BYU 16873-6). 26 mi W San Juanito, 7 (BYll 16960-6). 22.5 mi S Creel (along La Bufa road), 4 (BYU 16947-50). 25.5 mi S Creel (along La Bufa road), 16 (BYU 17654-5, 176.59, 17661-2, 17664, 17666, 17668- 70, 17672-4, 177.59, and 17021-2). 4-8 mi SE Maguarichic, 14 (BYU 17056-69). 16 mi NE San Juanito, 4 (BYU 17024-7). 20 mi S W Colonia Juarez, 2 (BYU 20973-4). Carmen Bridge (La Bufa road), 1 (BYU 22719). 1 mi W Carmen Bridge, 4 (BYU 22668-71). La Mesa de Arturo, 1 (BYU 22672). Turkey tanks SW Colonia Juarez, 1 (BYU 41760). ] 400 Great Basin Naturalist Vol. 47, No. 3 Fig. 4. Dorsal head scale variations in Sceloporusj. jarrovii. See text for explanations. We found this species to be widespread in all suitable habitats throughout the western mountains. It was commonly seen in areas where rocky outcroppings occurred and on boulders strewn along roads. It is apparently replaced in the foothills and central valleys by S. ti. consobrinus and S. poinsettii. There is noticeable variation within some populations in the number of dorsal scales. This variation is reflected in samples from different basins; for example, in Cerocahui 12 specimens have 39-44 (x = 41.1), and speci- mens 7 to 10 mi SE San Juanito have 37-40 (x = 38.8). However, when all specimens from south of the Rfo Papigochic are included, the following data are obtained: 96 specimens 37-45 (x = 40.4). This is generally true for specimens north of the Rio Papigochic in which 52 specimens range from 37-44 but average 41.2 scales in the dorsal series. The femoral pores vary from 12 to 18 per femur and show population variation as in the dorsals but with the southern population tending to have higher numbers than those north of the Rio Papigochic. The head scales are also variable. The relationship of the inter- parietal to the frontal, as an example, shows the following as illustrated in Figure 4. In A, 61 specimens or 41% are as illustrated; B, 34 specimens are 23%; and C, 53 specimens are 36%. Other dorsal head scales show some pat- tern variations but were not examined. The labials varied little with the upper la- bials, 4-4 rarely 5, and the lower labials usu- ally 6-6 but occasionally 5 or 7. In 51% of the total series the nasal was in narrow or broad contact with the anterior lorilabial. The most stable pattern was that of the sublabials. which do not contact the mental, thus permit- ting contact of the postmental and the first infralabial. In 148 specimens only 3 submen- tals contact the mental on one side. Since collecting was done from May to Oc- tober, the BYU series includes all age groups. On 28 June 1958, a gravid female, 75 mm S-V, was collected 25 mi W of Colonia Juarez. She contained 7 well-developed embryos, 4 fe- males and 3 males, ranging in S-V length from 22 to 24 mm. All color and scalation patterns were fully developed. In the latter, the hemipenes were fully everted. At this locality on the same day, 3 young were collected and measured 25, 26.5, and 27 mm in S-V length. These data indicate that birth in the moun- tains occurs in middle to late June. On 5 July 1958, at Black Canyon, 8 mi W of Chuhuichupa, 4 young were collected. These measured 24.6, 28, 29, and 31 mm S-V. Four juveniles collected at Cuiteco on 28 July 1958 measured 42-44 mm in S-V. Elevation may be a factor since specimens taken at about the same dates in 1957 and 1958 at Chuhuichupa and near Creel (8,000 feet) were smaller (35-37 mm S-V) than those taken at a lower elevation at Cuiteco. By Octo- ber the year's young are 50-60 mm S-V. Sceloporus slevini Smith Sceloporus sedans slevini Smith, 1937, Occ. Pap. Mus. Zool. Univ. Michigan 361:3-4. Scelopor-us scalaris Thomas and Dixon, 1976, Southwest- ern Nat. 20(4):523-536. Madero Canvon (Tureze), 1 (BYU 1326). Cerocahui. 3 (BYU 14603-4, 1.5489). 2 mi S Creel, 1 (BYU 1.5.597). 3 mi N Chuhuichupa, 4 (BYU 13799, 15717-9). Meadow Vallev, 1 (BYU 15714). July 1987 TANNER: Lizards AND Turtles OF Chihuahua 401 12 mi S\V Mifuica, 2 (BYU 15506, 15770). 6 mi S San Jiianito, 1 (BYU 17096). In Chihuahua thi.s species is found only in the western mountains at elevations ranging from about 6,500 to 8,000 feet. Records from the lower central ranges and valleys, such as Chihuahua City or 30 mi S El Paso (Smith 1937), were not confirmed by our collecting in these areas. Their habitat of grassy, low- growing herbs and brush did not make for easy collecting and consequently large series were not taken. All adults in this series varied in S-V length from 46 to 56 mm. The smallest is a male and the largest a female. Dorsals were 40-47 (x ^ 42. 92), femoral pores 12- 16 per femur or total pores 25-30 (x - 27.8). Other scale patterns were within those listed by Smith (1939). Color patterns showed some individual varia- tion but were well within patterns previously established for the subspecies. Except for one specimen, BYU 13799, taken on 27 August 1957, all were collected during July. Three of those from north of Chuhuichupa (2-6 Julv 1958), one from Ce- rocahui (BYU 15489. 13 Julv), and one from south of Creel (BYU 15597, 20 July) were gravid females. They ranged in size from 47 to 55 mm S-V and contained 4-7 eggs. The largest contained 7 eggs, and the smallest 4. The larger eggs in each indi\'idual measured 6-11 mm. All were heavily laden with yolk and the larger ones were compacted, except in the specimen with only 4 eggs, thus ac- counting for the round rather than elongated shape. The larger eggs were in specimens taken in late July. We saw no hatchlings and suspect that eggs are laid in late July or early August. Hatch- lings would seem to appear in late August or September. Sceloporus nclsoni harrancorum Tanner & Robison Sceloporus nelsoni coeruleus Tanner and Robison, 1959, Great Basin Nat. 19(4); 79-81. Sceloporus nelsoni harrancorum Tanner and Roljison, 1962, Herpetologica 16(2): 114. Sceloporus nelsoni: Hardy and McDiarmid, 1969, Univ. Kansas Publ, Mus. Nat Hist. 18(3): 136-38. Urique, 10 (BYU 14315-20 and 14.322-5). Teradakvva Creek near Rio Urique, 1 (BYU 22721). 3 mi NE Temoris, 1 (KU 51795). 1.5 mi Tociiina, 14 (KU 47426-28, 51060-70). 23 mi S 1 1/2 mi E Creel, Barranca del Cobre, 1 (KU 44293). 6 km NE El Fnerte, Sinaloa, 7 (KU 78669-75). 16 km NNE Choix, Sinaloa, 9 (KU 73728). 9 mi SE Alamos, Sonora, 9 (KU 47.537-45). 8 mi SE Alamos, Sonora, 4 (KU 49702-5, 91498, 176533). Cuirocoba (Sonora), 1 (MCZ 37855). Rio Mayo Guasaremos (Sonora), 1 (MCZ 43276). Other material examined: Sinaloa: 32 mi SSE Cu- liacan (KU 37773), 1.5 mi E Santa Lucia (KU 448,33-.39), 1 mi E Santa Lucia (KU 44840-49), 12 mi N Culiacan (KU 4485), 1 mi SE Camino Real, Rio Piaxtla (KU 63706-8), 44 km ENE Sinaloa (KU 69932), 6 km E Cosala (KU 73729), San Igna- cio (KU 73730-32), 5 km SVV El Palmito (KU 75582), 8 km N Carrizalejo (KU 78676-77), 5 km SW San Ignacio (KU 78678-79), 8 km N Villa Union (KU 80731), 13 mi ESE Badiraguato (KU 83400), 5 mi E Presa Sanalona (KU 93479). Sceloporus n. nclsoni, type USNM 47676 and paratypes USMN 18979, 47271, 47273-5, 47629, 47690-1. Nayarit: 18 mi S Acaponeta (BYU 14383-4). Jalisco; 3 mi N Guadalajara (KU 27202-3). Hardy and McDiarmid (1969) examined a series of 72 specimens, 56 from localities in Sinaloa and 16 from southwestern Chihuahua. They did not study specimens from the type locality nor from the type series reported by Tanner and Robison (1959). A reexamination of the data from the type series of n. nelsoni and M. harrancorum and an evaluation of the material now available from or near the type localities indicates that a further examination of the variations in these subspecies is justi- fied. In the original description of S. n. harran- corum some characters were not clearly de- fined. Therefore, it appears appropriate and necessary to diagnose and redescribe S. n. harrancorum and provide a key for the identi- fication of the subspecies. This can now be done based on a larger series from both the northern and southern populations. Diagnosis. — Sceloporus n. harrancorum is smaller than S. n. nelsoni, S-V of 30 adults, male, 54-60.0 (x = 56.5 mm), female 50.5-55.0 (x ^ 52.6 mm) in contrast to speci- mens from near Santa Lucia and other areas near the type locality of n. nelsoni at Plo- mosas, Sinaloa; males, 58.0-68.2 (x = 62.84 mm) and females 56.1-59.1 (x = 57.25 mm); enlarged postanal scales present, color pat- tern in males with the ventral surface (gulars and belly) a deep blue, no white except a small white spot near each shoulder, dorsolateral stripes faint or absent, venter of adult females 402 Great Basin Naturalist Vol. 47, No. 3 Fig. .5. Paratype ofSceloporus n. harrancorum (BYU 14.317) showing the enlarged postanal scales. with pale blue laterally and edged medially by a narrow stripe of dark blue, blue on belly in females separated by a narrow median light stripe, which is absent in males. Description and Comparison. — Some characters that seemed important previously are now, based on added material, obvious variations. The head scales do show variations but not consistent in any one pattern, and the lamellae of the fourth toe do not vary. Other characters such as adult size, color patterns, and enlarged postanal scales represent signifi- cant differences between nehoni populations from southern Sinaloa and Nayarit and popu- lations in northern Sinaloa, southern Sonora, and southwestern Chihuahua. The description of S. n. harrancorum was based on the type series (10 specimens) and compared with the type series of S. n. nehoni at the USNM and two specimens from 18 mi S Acaponeta, Nayarit. In the study by Tanner and Robison (1959) it is clearly stated that the northern populations (southwestern Chi- huahua) were smaller than typical (type se- ries) nehoni . An examination of the data pre- sented by Hardy and McDiarmid (1969) indicates that their analysis of size data in- cluded juvenile specimens. Such data are not representative of the actual adult size in a population. I have examined the 19 speci- mens seen by Hardv and McDiarmid (1969) from Villa Union (KU 80731), El Palmito (KU 75582), and Santa Lucia (KU 44833-39 and KU 44840-49). My measurements of S-V of 14 adult males of this series range from 58.0 to 68.2 mm and average 62.84 mm, in contrast to their measurements, 42-65 (x 58.0). Al- though Hardy and McDiarmid (1969:136) state that "the maximum snout-vent length is slightly smaller in Chihuahua and northern Sinaloa than in southern Sinaloa, ' they fail to corroborate this observation in their data (p. 137, Table 4). In small species, such as nel- soni, an increase of 4-5 mm in the S-V of adults substantially increases the body mass and is obvious by inspection. By eliminating juveniles and segregating males and females, a size differential between populations (sub- species) is evident. The presence or absence of enlarged postanal scales was not considered in the Hardy-McDiarmid (1969) study. Cochran (1923:186) states that males have "slightly de- veloped post-anal scales." Smith (1939:364), in the diagnosis of the species, states that there are "no enlarged postanals in males." In the type series of S. n. harrancorum all males (5) have enlarged postanals (Fig. 5). In the series from Santa Lucia, Sinaloa (KU 44833-44849), only one male has slightly en- larged postanals. I have not examined the type series oi nehoni for this character. Smith lists 38 specimens with all but 3 from localities near or south of Mazatlan in southern Sinaloa, Nayarit, and Jalisco. That he could not find enlarged postanals is not surprising, since this character apparently becomes more promi- nent in specimens at or north of Culiacan. Most adult males I have seen from northern Sinaloa (El Fuerte and Choix), southern July 1987 TANNER: Lizards and Turtles of Chihuahua 403 Fig. 6A. Four specimens ofSceloportis n. nelsoni from 18 mi S Acaponeta, Nayarit (BYU 14383), 1 mi E Santa Lucia (KU 44845), and San Ignacio, Sinaloa (KL' 73730-31), depicting the basic ventral color pattern of the southern subspecies. Sonora (near Alamos), and southwestern Chi- huahua have the postanals enlarged. Color patterns in the two subspecies are variable but distinct, with males of S. n. har- rancorum having an intensive blue covering the entire venter from gulars to groin, and only small white spots medial to the shoulders (Fig. 6A). Males from southern Sinaloa have considerable white or cream coloring be- tween the front legs and on the adjoining gu- lars. In some the blue belly patches are sepa- rated by a narrow mid-ventral light area not seen in males of the northern subspecies (Fig. 6B). The dorsal color pattern for males of S. n. harrancorum is as follows: two faint dorso- lateral stripes, with the area between heavily pigmented with dark bluish brown of approxi- mately the same color as the area immediately lateral to the stripes. Females are less pig- mented, the dorsal gray not contrasting with the gray below the dorsolateral lines. In S. n. nelsoni there is less bluish green in the dorsal pattern. The dorsolateral lines are more distinct, and the dorsal area between the lines is a lighter brownish gray than the lateral area. As in the females of northern populations, there is less pigmentation, giv- ing a gray pattern. The following scale characteristics are based on the series of 17 specimens from near the type locality of S. n. nelsoni and con- trasted with a series of n. nelsoni from near Mazatlan and the type series of S. n. harran- corum from Urique, Chihuahua. At or near the type locality of n. nelsoni the dorsals in the 14 male specimens range from 35 to 39 (x ^ 37.06). The series from near Mazatlan range from 36 to 40 (x ^ 37.89). The series from Urique range from 38 to 43 (x = 39.5). In the femoral pores in the same order the range is 31-39 (x = 33.82). The intermediate series is 29-40 (x = 34.10) and the Urique series 34-38 (x = 36.82). Other head scale charac- teristics show little modification between the southern and the northern series except that there is a noticeable variation in the size of the large scale immediately posterior to the inter- 404 Great Basin Naturalist Vol. 47, No. 3 Fig. 6B. Four specimens of Sceloporus n. harrancorum (KU 51065, 51069, 51060, and 51067) from 1 1/2 mi SW Tocuina, Chihuahua, showing the dark (blue in hfe) venter from chin area to groin. parietal. The figure in the original description of S. n. harrancorum (Tanner and Robison 1959, Fig. 2, original description S. n. coeruleus) depicts a scale much larger than the adjoining ones. This size differential is maintained in approximately 90% of the speci- mens designated above as S. n. harrancorum. In S. n. nelsoni this scale is reduced in size and in many specimens is the same size as or sube- qual to the surrounding scales. In these sub- species, as well as in other species where gradual intergrading of characters occurs, there are the expected clinal variations be- tween the subspecies. Remarks. — Apparently the specimens re- ferred to by Smith (1939) from Guirocoba, Sonora(MCZ 37855), and Rio Mayo, Guasare- mos, Sonora (MCZ 43276), and the specimen from Culiacan, cited by Cochran, were not seen by Hardy and McDiarmid (1969). The two Sonora specimens are identical in both scale and color pattern to the type series of S. n. harrancorum. That Smith (1939) did not consider the data based on three specimens (widely separated geographically) to be suffi- cient to establish or warrant subspecific recog- nition of the northern populations is not sur- prising. Only one of the three specimens (MCZ 37855, an adult male) would have pro- vided the basic data for comparison with the southern populations oi nelsoni. Key to the Subspecies 1. Adult males with enlarged postanal scales; gu- lars and entire venter a deep blue (except for two small cream-colored spots near shoulders); adults smaller, males 54-60 mm, females 50-55 mm in S-V length S. n. harrancorum — Adult males usualK without enlarged postanals; a large area of light (white to cream) color be- tween front legs separating the blue of the gulars and the belly; adults larger, males 58-68, fe- males 56-59 mm in S-V length S. n. nelsoni Genus Urosaurus Urosaiirus ornatus Baird & Girard The ornatus complex in Chihuahua is not well represented by specimens, nor are the subspecies clearly defined. A lack of speci- mens has made it difficult to determine distri- bution parameters for the subspecies that July 1987 Tanner: Lizards and Turtles of Chihuahua 405 ^•''^, ►•»c^ — ^ Fig. 6C. Type of S. n. harrancorum (BYU 14316), dorsal and ventral views. have been reported for the state. Based on the material at hand, literature records, and the available keys (Smith and Taylor 1950), the following subspecies should occur in northern and central Chihuahua: Urosaurus o. schmidti Mittleman, Urosaurus o. caeruleus Smith, and Urosaurus o. linearis Baird. The latter may occur only in extreme northwest- ern Chihuahua. Specimens of linearis are not available, and its relationship to other subspe- cies {caeruleus, schmidti, and schottii) as well as its distribution must be established before it can be recognized. In southwestern Chi- huahua, Urosaurus bicarinatus tuberculatus Schmidt occurs. Tanner and Robison (1959) examined the type of Urosaurus unicus Mittleman, type locality Batopilas, Chihuahua, and determined it to have the same basic charac- teristics as Urosaurus h. tuberculatus . Mittleman (1940) described Uta o. schmidti and listed a specimen (MCZ 45589) from Colonia Garcia, Chihuahua, as a paratype. While I am not questioning it as a representa- tive of the subspecies, I doubt that it came from a mountain habitat such as Garcia. In 1941 Mittleman placed U. o. lateralis as a synonym of U. o. schottii Baird. Hardy and McDiarmid (1969) recognized the subspecies lateralis as occurring in Sinaloa NNE of Choix, a locality near southwestern Chi- huahua. Bogert and Oliver (1945), based on the study of Oliver (1943), recognized U. o. lateralis, rather than U. o. schottii Mittleman, as occurring in Sonora. Although I am un- aware of specimens of the subspecies U. o. lateralis from southwestern Chihuahua, it un- doubtedly occurs, as do many other species, as distributional extensions along the rivers of the Rio Fuerte basin. To fully understand the systematics of Urosaurus ornata and its subspecies would require a major study, which is beyond the scope of this study. The species and subspe- cies listed here are based on limited material from Chihuahua and, therefore, on my best judgment of the available specimens. Urosaurus ornatus caeruleus Smith Uta caerulea Smith, 1935, Univ. 22:172-178, pi. 26. Kansas Sci. Bull. 406 Great Basin Naturalist Vol. 47, No. 3 Urosaurtis ornata caeruleus Mit\\envan, 1942, Bull. Mus. Comp. Zool., 19; 136- 1.37, pi. 9, Colonia Dublan, 4 (BYU 1327, 29.57, .3711-12). 18.5 mi E Ricardo Florcs Magon, 2 (BYU 13403-4). 45 mi S Gallego (Highway 45), 1 (BYU 141.57). 6.5 mi N 1.5 W Chihuahua City, 1 (BYU 1,582.5). La Cruz, 15 mi NNW Camargo, 1 (UTEP .3.580). 24 mi (air) NNE Ascension, 4 (UTEP .3.563-6). 14 mi SE Janos, 1 (UTEP 4269). 6 mi NE Janos, 1 (UTEP 4270). 10 mi SSE Cd. Chihuahua, 1 (UTEP 4.599). 16.3 mi (bv Hw>' 16) NE Aldama, Puerto de Gomez, 2 (UTEP 9212-1.3). The characteristics of the above specimens are well within those established by Smith (1935). In adult males (S-V 42-50 mm) the entire venter is a vivid sky blue, with spots of blue on the base and lateral sides of the tail. In small or subadult males the blue is less intense and faded at the edges. The venter of females is without blue. Dorsal color pattern consists of seven irregular cross bars from nape to groin. The dorsal color is heavily pigmented between the bars, giving a melanistic appear- ance. All of the scale patterns are within those set forth in the original description (Smith 1935). The ventrals, gular fold to anus are 57-68 (x ^ 61.7). Some scale patterns will be compared to other populations discussed below. In all but a few the head is slightly longer than wide, but less so than in two specimens o( schmidti; extremes are: length 9.4 to width 7.5 and 9.6 to 9.8 mm. Other specimens range between these extremes. Femoral pores range from 9 to 13 and total 18 to 27 per individual. Two of the specimens are hatchlings with a snout- vent of 20.5 mm (BYU 14157) and 24.5 mm (BYU 15825). They were collected 13 August 1957 and 28 July 1958. Urosaurus ornatus schmidti (Mittleman) Ufa ornatus schmidti Mittleman, 1940, Herpetologica 2(2):33-34. Urosaurus ornatus schmidti MiMemMt, 1942, Bull. Mus. Comp. Zool. 91:135-136. The recognition of this subspecies is based entirely on the specimen (DHD and HMS No. 72) reported by Smith (1935) from 3 mi S of Samalayuca, Chihuahua, and two speci- mens (UTEP 3362-3) from 7 mi NW of Indian Hot Springs, Texas, presumably across the Rio Grande in northern Chihuahua. In our limited collecting south of Ciudad Juarez to Villa Ahumada we did not see a Urosaurus. Both UTEP specimens are females with the following characters: ventrals 64, 64; femoral pores 13-13 in both and with S-V length 41 and 48.2 mm, respectively. The color is light gray to cream on both the dorsal and ventral surfaces, with little spotting dorsally and im- maculate ventrally; large preshoulder blotches present in U. o. caerulea are repre- sented in schmidti only as a small dark spot; enlarged dorsals variable in size but equal or subequal to prefemoral or pretibial scales. Head longer than wide, 9.8 to 8.4 and 9.2 to 7.6 mm, respectively. Enlarged dorsals begin at shoulders and extend to base of tail. Urosaurus ornatus schottii (Baird) Uta schottii Baird, 18.58, Proc. Acad. Nat. Sci. Philadel- phia 10:2.53. Urosaurus ornatus schottii Mittleimin. 1942, Bull. Mus. Comp. Zool. 91:137-139. Rio Bavispe below Tres Rios near Chihuahua- Sonora state line, 21 (BYU 1.3427-8, 1.3430, 1.34.36-8, 1.34.53. 13461, 1.3466-8. 1.3471, 13473, 13503, 13507, 1.3.595, 145.59-62, 14.565-6). Although there is some doubt as to the ex- actness of the type locality, if we assume, as have others (Mittleman 1942, Smith and Tay- lor 1950), that it is in north and central Sonora, then the vicinity of Magdalena may represent the most logical area. Past studies of this spe- cies in Sonora (Mittleman 1942, Oliver 1943, Smith and Taylor 1950) have not agreed as to which subspecies of ornafa occur in Sonora or Chihuahua nor as to their present distribu- tion. Bogert and Oliver (1945) list U. o. later- alis for the entire state of Sonora. Smith and Taylor (1950) do the same for U. o. schottii and exclude lateralis. It may be that both occur, one in the north (schottii) and one in the south (lateralis), with the latter extending into Sinaloa (see Hardy and McDiarmid 1969). In attempting to allocate the Rio Bavispe specimens, we compared them with a few specimens from the following localities in Sonora: 12 mi NW Altar, Kino Bay, 23 mi N Kino Bay, 10 mi N Guaymas and Ortiz. Although there is variation in these and the Rio Bavispe series, all were well within the basic characteristics, as I understand them, for U. o. schottii. The following characters were noted: two rows of enlarged dorsals com- mencing on the nape and separated by a series of small middorsal scales. Each row of en- larged dorsals consists of two rows of enlarged July 1987 TANNER: LiZARDS AND TURTLES OF ChIHUAHUA 407 scales of equal or subequal size. In most speci- mens the outer rows were smaller but this was not a consistent character. In most specimens (80%) the enlarged dor- sal scales extend onto the posterior part of the nape. In this there is variation ranging from the angle of the shoulder to approximately halfway to the parietal area. The small mid- dorsal scales are irregular in size and are usu- ally two (not more than three) in number across the median. They extend beyond the base of the tail for 3 to 10 of the enlarged dorsal tail scales. Males have blue belly patches, which in some are divided medially b> a light stripe. Most adults are a solid blue from axilla to groin, with little or no blue between the front and hind legs. Females possess faint blue ven- tral patches or are without them. Gulars are faint blue in the middle only, not extending to labials. The area of the gular fold is spotted and without blue. This is in contrast to caeruleus. Scales on the forearm are etjual to but usually not larger than those of enlarged dorsals. Usually a distinct dark collar extends from in front of the shoulder to or nearly to the enlarged dorsals. A series of 4 or 5 dark, irreg- ular blotches occur from nape to base of tail and usually involve the dorsolateral row of enlarged tubercles. This pattern is in contrast to 6-7 blotches in caeruleus. The measurement ratios of head width to length were too variable to be useful. The head length average for 20 Rio Bavispe speci- mens is 9.5 and width 8.6; two of the 20 had heads wider than long (9.4 - 9.9 and 8.5 - 9. 1). In others the length was 0.5 to 1.0 mm longer than wide. The S-V measures were 41-49 mm in the Rio Bavispe series and for northern and western Sonora 40-50 mm. Specimens of U. ornata are not available from southwestern Chihuahua. Yet, there is every reason to suspect their presence in the lower Urique basin north of Choix, Sinaloa. The subspecies U. o. lateralis would be ex- pected to occur since it is in southeastern Sonora and northeastern Sinaloa. A specimen (BYU 36824) from 15 km ENE of Navojoa, Sonora, has the basic characteristics as pre- sented by Oliver (1943), only one row of en- larged dorsals on each side of the small mid- dorsals; enlarged dorsals extending nearly to parietals; scales on forearm smaller than en- larged dorsals. It is an adult male and quite distinct from the more northern specimens of ornata. Urosaurus hicarinatus tuherculatus (Schmidt) Vta tuherculatus Schmidt, 1921, Amer. Mus. Nov. 22:4. Urosaurus hicarinatus tuherculatus Mittlenian, 1942, Bull. Mus. Comp. Zool. 91:169-170. Urique, 1 (BYU 14321). Near Pitahaya, 1 (BYU 22681). Two other specimens have been examined: KU 47401 from La Bufa and USNM 14248 from Batopilas. The latter is the type of Urosaurus unicus Mittleman and was com- pared to the Chihuahua specimen from Urique and nearbv Sinaloa specimens by Tanner and Robison (1959). Oliver (1943) questioned the validity of U. unicus, and Hardy and McDiarmid (1969) agreed that it was at best a variant of U. b. tuherculatus. My examination of the unicus type provided no characters that were not well within the variable parameters of the subspecies U. b. tuherculatus. The extent of the distribution of tuhercula- tus in Chihuahua is as yet unknown. It does occur in the lower portions of Rio Urique and Rio San Miguel. Genus Uta Uta stanshuriana stejnegeri Schmidt Uta stanshuriana stejnegeri Schmidt, 1921, Amer. Mus. Nov. 15:1-2. 36 mi S Ciudad Juarez, 1 (BYU 15192). 6 mi N Chihuahua City, 1 (BYU 15815). In all of our collecting we did not find this species to be common in Chihuahua. Be- tween Silver City and Deming, New Mexico, utas were seen regularly, but they seem to be replaced in the desert flats of northern and central Chihuahua by the earless hzard Hol- hrookia maculata. In spite of extensive col- lecting in the greater Casas Grandes area, we did not see a Uta, although Holbrookia was abundant. There is reason to believe that the distribu- tion of Uta is primarily in eastern Chihuahua, that is, east of Highway 45 and extending east into Coahuila and south through the more desert areas to eastern Durango. The scarcity of utas from Chihuahua is also suggested by Ballinger and Tinkle (1972), who did not list a 408 Great Basin Naturalist Vol. 47, No. 3 single specimen from the state (see Ballinger and Tinkle, Fig. 1 and p. 40, material exam- ined), and yet their distribution map (Fig. 5) includes most of Chihuahua. Smith, Williams, and Moll (1963) list 37 specimens taken along the Rio Conchos between Julimes and northeast to Alamo. Smith and Taylor (1950) list a single locality, 15 mi S of Ciudad Juarez. The distribution of this species in Chi- huahua and its distributional relationship to Holbrookia maculata are yet to be deter- mined. Family Scincidae Genus Eumeces Smith and Taylor (1950:219) list four spe- cies oi Eumeces as occurring in the Mexican state oi Chihuahivd {callicephalus , midtivirga- tus, obsoletus, und parviauriculatus). Zweifel (1954) included brevirostris and Anderson (1962) added brevilineatus . Tanner (1957) ex- amined the USNM 30833 specimen, which was listed by Smith and Taylor (1950) as a questionable representative of the species midtivirgatus, and, with this one and two ad- ditional specimens, named the Chihuahua specimens E. multiline ai us . A collection of skinks from Durango and Chihuahua exam- ined by Tanner (1958) resulted in the descrip- tion of £. brevirostris bilineatus. The occurrence of the species lynxe in the western mountains of Durango and humilis and parvulus in the eastern foothills of Sinaloa suggests, on the basis of the many species that have recently been taken in similar habitats in southwestern Chihuahua, that additional spe- cies may occur in the state when adequate collecting is done in the rough terrain of southern Chihuahua. My experience indi- cates that skinks tend to be gregarious. In two similar and nearby habitats, one may have skinks and the other may not. Thus, collecting must be intense and complete. This type of collecting is far from true for much of south- western Chihuahua and apparently also for the rugged mountains and foothills of eastern Sinaloa and northern Durango. Eumeces tctragrammus brevilineatus (Cope) Eumeces tetragrammus brevilineatus (Cope), 1880, U.S. Nat. Mus. Bull. 17; 18- 19, 44, 46; Taylor, 1935, Univ. Kansas Sci. Bull. 23;283-290; Anderson, 1962, Herpetologica 18(l);56-57; Lieb, 1985, Contributions in Sci., Nat. Hist. Mus. Los Ange- les County 357:1-19. 5 mi N Cerro Campana, Sierra del Nido, 2 (MVZ 70702-3). Lieb (1985) lists specimens for: Santa Clara Canyon, 4.5 mi E Mx Highway 45 (LACM 11640), Sierra del Nido, 4.7 mi W Encinillas (UTEP 62). Anderson (1962) reported that this range extends into the Sierra del Nido of Chihuahua. Although this species may not have been expected by Anderson, its occur- rence is not a complete surprise considering the pockets of other species now known to have extended their distribution from the north and east into Chihuahua. The presence of Phnjnosoma douglassii, Thamnophis ele- gans. Thamnophis sirtalis, and Opheodrys vernalis are examples of species whose distri- bution apparently was present in this area before, during, or immediately after the re- cent ice age. The following desiccation re- sulted in dispersing those species requiring a more mesic habitat from the low desert val- leys into the foothill and mountain habitats. Disjunct distribution and isolated pockets have resulted. A careful examination of the above species would show, as has Opheodrys vernalis, the disruption of a once widespread and certainly a more uniform distribution than is presently known (Conant 1974). Eumeces callicephalus (Bocourt) Eumeces callicephalus (Bocourt), 1879, Miss. Sci. Mexique et Centr. Amer. 6;431-433; Taylor, 19.35, Univ. Kansas Sci. Bull. 23;290-298. Eumeces tetraf^ravunus callicephalus Lieb, 1985, Contri- butions in Sci., Nat. Hist. Mus. Los Angeles County 357; 1-19. Ri'o Bavispe at or near Chihuahua-Sonora line be- low Tres Rios, 7 (BYU13145-.50 and 14233). 2 mi E Cerocahui, 3 (BYU 14248-50). Cuiteco, approx. 1 mi NW in steep rocky canyon, 11 (BYU 14259-61, 14608-14615). 3 mi W of Carmen Bridge (across Rio Urique), 1 (BYU 22689). Along trail just west of can\on rim west of Urique, 1 (BYU 14338). Taylor (1935) lists one from Madera (MCZ). Lieb (1985) lists the following additional speci- mens; Guasaremos (MCZ 4,3389-90), 8 mi W Ma- tachic (AMNH 68295), Pacheco (MVZ 46672), and 3 mi NE Temoris (KU 51462). Because Eumeces callicephalus exhibits several distinct characteristics, it is deemed justifiable to retain it as a species rather than a subspecies of the tctragrammus group. It is understood that a close relationship exists be- July 1987 TANNER: Lizards andTurtles OF Chihuahua 409 tween caUicephalus and hrevilineatus- tetragrammus; however, they both seem to be evolving with several distinct characters. Salient characteristics of caUicephalus re- ported by Lieb (1985) include: a divided post- mental scale, postnasal scale present on one or both sides, one or both primary temporals contact parietal, a single postlabial on one or both sides, interparietal enclosed by parietals and a wide separation in distribution (Lieb 1985, Fig. 4). Eiimeces caUicephalus has its entire distribution west of the Continental Divide, whereas hrevilincatus -tctragrammus group is primarily found in the Sierra Madre Oriental of Mexico, southwestern Texas, and the desert ranges extending west to the iso- lated population in the Sierra del Nido of Chi- huahua. The distribution of £. caUicephalus is diffi- cult to explain. All specimens so far collected were taken west of the Continental Divide (except the specimen taken at Pacheco (Lieb 1985), and yet the habitat on the east side in some areas appears ideal. Why the east slopes of the mountains are not occupied is an enigma. If hrevilincatus is established in the Sierra del Nido, why not in the Sierra Madre, a relatively short distance to the west when compared to the much greater distance to suitable habitat in Coahuila to the east? The terrain extending west from the Sierra del Nido consists of low mountain ranges which interconnect and provide, in my opin- ion, a suitable distribution lane for either spe- cies. The fact that neither apparently did sug- gests that these populations, even though closely related, have been separated for a long time and, since both have continued to oc- cupy similar habitats, have retained relating characters. Our attempt to understand the moq^hological and distributional changes that have occurred and may yet be occurring in the species of this area as a result of the desicca- tion following the recent ice age is still a major challenge. The elevational distribution of caUi- cephalus may range to at least 2,000 m. The specimen taken just west of the rim above Urique was at about 7,500-8,000 feet in a habitat of oak-madroiio-pine with open spaces of rocky outcroppings. Lieb (1985) lists the range to be 900-1,700 m. We found this spe- cies to inhabit the canyon of the Rio Bavispe and its tributaries (Nutria Creek) of western Table .3. The percentages and freqnencies of the fol- lowing characteristics as observed in 25 specimens of pAtmeces t. caUicephalus from western Chihuahua, Mex- ico. Characteristics Percent/number Postmental divided 100/25 Postnasals present 75/19 Interparietal enclosed 80/20 Primary temporal contacts 40/10 parietal one or both sides Postlabials 100/25 single one or Iioth sides Nuchal Y-mark present 100/25 Scale rows 28 56/14 Scale rows 26 44/11 Dorsal scales 54-60(56.25) parietals to base of tail Chihuahua and eastern Sonora. It did not oc- cur in the higher elevations north of the Rio Papigochic where we found E . multilineatus. South of the Papigochic and west of San Juanito (Maguarichic and Mojarachic) in the higher elevations, E. brevirostris and E. parviauriculafus occur. It is south of Creel on the west rim of the Rio Urique that we found caUicephalus in areas at or above 1,700 m. Lieb (1985:8) indicates by map that E. caUi- cephalus is found in the mountainous headwa- ters of the Rio Oteros. As noted above, we found only E. brevirostris and E. parviauric- ulatus, and suspect E. caUicephalus to be at lower elevations near the Sonora border. During 13-18 July 1958, 10 hatchlings, 8 at Cuiteco, 1 east of Cerocahui, and 1 near the west rim of Urique Canyon, were collected. Those west of Cuiteco were recently hatched. A nest of four young, still with the female, were taken from a nest between two large rocks. This nest was on the northeast side of the canyon and in partial shade for part of the day. Four young of another nest were found under a rock about six feet away, but in the same rocky area. They measured 22.8-25.4 mm snout to vent. Those hatchlings taken east of Cerocahui and on the canyon rim were also of this same size. On 26 September 1963 a juvenile was taken below the Carmen bridge near the Ri'o Urique (BYU 22689). It mea- sured 38.0 mm snout to vent. An analysis of the characteristics of the 25 specimens collected in Chihuahua is summa- rized in Table 3. Several characters in this 410 Great Basin Naturalist Vol. 47, No. 3 series are not consistent with previous studies (Taylor 1935, Lieb 1985). The most notable variation is that of the contact between the primary temporal and the parietal, in which only 40% are sutured. There is a reduction in the percentage of individuals having 28 scale rows around the body. Two adult females each have 26 rows; of the 8 hatchlings collected with them, 3 have 28 and 5 have 26 rows. In the other 15 specimens, only 3 have 26 rows. I could not discern more than one post- labial, although there are small scales near and above its posterior end and near the ear openings. The postnasals vary in size, which suggests that they represent a portion of the posterior part of the nasal. The size of the anterior loreal does not seem to vary when postnasals are present, but the posterior part of the nasal is noticeably reduced in size when a postnasal is present. The three characters most typical and consistent in the Chihuahua series are: (a) a divided postmental, (b) a nuchal Y-mark, and (c) complete lateral and dorsolateral light stripes. Etimeces obsoletus (Baird & Girard) Plestiodon obsoletum Baird and Girard, 1852a, Proc. Acad. Nat. Sci. Philadelphia 6; 129 (type locality. Valley of the Rio San Pedro, tributary of the Rio C^rande del Norte, Texas). Eumeces obsoletus: Cope, 1875, Bull. U.S. Nat. Mus. 1:45. Taylor (1935) hsts a specimen (USNM 1) for the "City of Chihuahua. Whether this refers to Chihuahua City is not clear. We spent con- siderable time collecting in the vicinity of Chi- huahua City and west to Cuauhtemoc, also in the grassy foothills between Casas Grandes and Colonia Juarez without seeing this spe- cies. At the present writing, I am aware of only one other specimen collected in Chi- huahua, reported by Legler and Webb (1960) from Guadalupe Victoria (approx. 50 mi SE of Chihuahua City), KU 44261. In view of the record reported above and since they do occur in the Big Bend area of southwestern Te.xas and in southern New Mexico, their range in Chihuahua may include suitable habitat in the desert areas of eastern Chihuahua. Eumeces multilineatus Tanner Eumeces multilineatus Tanner, 1957, Great Basin Nat. 17:111-117. Eumeces multiuirgatus mexicanus: Anderson and Wil- hoft, 1959:57. Eumeces multilim'dtus: Legler and Webb, 1960:18. Garcia, 1 (BYU 11984). 3 mi N Chuhuichupa, 8 (BYU 1,3798, 14226- 142,32). Yaguirachic, 11 (MVZ 660,56-66065). 15 mi S 5 mi E Creel, 1 (KU 44261). Chihuahua (no locality), 1 (USNM 30833). The distribution of E . multilineatus is at present confined to the higher mountains north and south of the Rio Papigochic. I am not familiar with the habitat at Yaguirachic, but from the description of Anderson and Wil- hoft (19.59), it seems similar to that at Garcia as described in the field notes of Dr. D Elden Beck (1931). Those taken north of Chuhuichupa were on the brow of a steep, rocky slope above the river and just below a grove of pine. We collected seven on 4 July 1958 from the same area, all from under rocks rather than fallen logs near a meadow as re- ported by Anderson and Wilhoft (1959). Legler and Webb (1960) reported a speci- men taken 15 mi S and 6 mi E Creel (7,300 feet) but did not indicate the type of habitat. The area south of Creel ranges in elevation between 7,000 and 8,000 feet and is habitat comparable to areas north of the Rio Papigo- chic. The original description of Eumeces multi- lineatus was prepared from two authentic specimens, one from Chuhuichupa and one from Garcia, plus a faded specimen USNM 308-33. Since this description, two additional populations have been added to the distribu- tion of the species, one from Yaguirachic and one from SE of Creel. Although there is little, if any, variation in the color pattern of the populations, there does appear to be variation in some of the scale patterns, particularly in the number of scale rows and dorsals. The eight specimens from Chuhuichupa are uni- form in having 24 scale rows around the mid- body, those from Yaguirachic are 24 except for one with 25, and the one from south of Creel has 25. The dorsals vary from 52 to 59 (55.5). The supralabials are consistently 7-7, as are the infralabials at 6-6. There are no post- nasals, and in none of the specimens listed above is the interparietal enclosed posteriorly by the parietals. The nuchals are 2-2. Per- haps the most noticeable characteristic in the three populations is the uniformity of the color pattern. The consistency of most of the above scale characters and the uniform color July 1987 TANNER; Lizards AND Turtles OF Chihuahua 411 [;545: Fig. 7. Dorsal view of the tvpe oi Eumeces miiltilinea- tus (BYU 13798) from 3 mi N Chuhuichupa, Chihuahua. pattern in contrast to mtiltivirgatus are per- haps some of the most significant factors in the estabhshment of multilineatus as a vahd spe- cies (Fig. 7). Eumeces miiltivirgatiis Hallowell Etimeces multhir^atuin Hallowell, 1857. Proc. Acad. Nat. Sci. Philadelphia 9;215. Eumeces miiltivir^atus mexicanus: Ander.son and Wilhoft 1959:57. Eumeces multivir^atus: Leglerand Webb 1960:18. 23 mi S 1.5 mi E Creel, 1 (KU 44260). Legler and Webb (1960) reported a juvenile specimen taken 23 mi S and 1.5 mi E of Creel. My examination reveals the following charac- ters: 26 scale rows at midbody, 56 dorsals, 1-1 postnasals, 2-3 nuchals, interparietal en- closed by enlarged parietals, a small scale sep- arating postlabial from ear lobules, and a color pattern quite unlike any E. multilineatus, but similar in basic pattern to multivirgatus seen from Arizona, New Mexico, and Utah. The color pattern as observed and de- scribed by Legler and Webb (1960) implies a relationship to the variations known to occur in multivirgatus. In none of the 20 specimens o( multilineatus examined by me do such color pattern variations occur, but rather a consis- tently uniform series of scale and color pat- terns. The following characters are distinctly different from those seen in multilineatus and similar to those commonly observed in multi- virgatus: postnasals usually present, 56-61 rows of dorsals (specimens from Arizona, Col- orado, and Utah), interparietal often enclosed posteriorly by parietals, 1 or 2 small scales between postlabials and ear lobules, and a faded variable color pattern. The Legler and Webb specimen is a recent hatchling and may not exhibit the adult color pattern. In multilineatus the color pattern does not seem to vary from hatchling to adult. The scale and color pattern characters do re- late this specimen to multivirgatus. At present its precise taxonomic status must await additional specimens. Eumeces parviauriculatus Taylor Eumeces parviauriculatus Ta\\o\\ 1933, Proc. Biol. Soc. Washington 46:178-81; Robinson 1979, Contri- butions in Sci., Nat. Hist. Mus. Los Angeles County 319:7-9. 2 mi N Maguarichic, 4 (BYU 16849-52). Robinson (1979) provides a distribution map and reports the following collection local- ities for this species: 4.8 km NE Temoris (KU 51463-64); La Pulvosa (UMMZ 114502); Mo- jarachic(FMNH 106476). Taylor (1933) described this species from a single specimen (USNM 56903) and reported with Knobloch (1940) two additional speci- mens (KU 18983-4) from the Sierra Madre of Chihuahua. A definite locality was not listed, but I was advised by Dr. Knobloch that these specimens were collected in the vicinity of Mojarachic. Six of the seven known specimens were found in mountains near the headwaters of the Rio Oteros at an elevation above 8,000 feet. This may bring into question the type locality at Alamos, Sonora. Since Goldman undoubt- 412 Great Basin Naturalist Vol. 47, No. 3 edly collected the other reported species while traveling and then reported from a base camp, it is not likely that Alamos, at 1,200 feet, is the type locality. Goldman (1951) vis- ited the Sierra de Choix (a southwest descend- ing range of the Sierra Madre) northeast of Alamos at elevations of 5,000-6,000 feet. I believe that E . parviauriculatus is a mountain inhabitant and is not to be found in the low coastal or foothill valleys much below 5,000 feet. This distribution is also suggested by Robinson (1979). The Maguarichic specimens consist of one adult female with a snout-vent length of 53 mm and three hatchlings ranging from 23 to 26 mm. They were collected to- gether on 15 July 1960. All were in a small burrow beneath two rocks on a southwest slope. The habitat consisted of open, rocky spaces between scattered, low-growing oak and other shrubs. To the west and south was the deep barranca of the Rio Oteros. This is the third species of which we collected hatch- lings during July {caUicephalus, 13-18 July 1958; midtilineatus, 4 July 1958 and parviau- riculatus, 15 July 1950). Except that the adult is larger, no other characters vary. In fact, all four are essentially duplicates when compared to the description and drawings of the type. The color pattern is basically the same but is not discolored, show- ing the dorsolateral stripes a light cream to white and extending from snout onto tail. A lateral stripe is present from labials to front leg. The area between the dorsolateral stripes is a mottling of grayish green, contrasting sharply with the dark brown below the dorso- lateral stripes. The venter grades from light to dark gray between the legs, and the gulars are a cream color. Eumeces brevirostris bilineatus Tanner Enrneces brevirostris bilineatus Tanner, 19.58, Great Basin Nat. 18(2):57-62 (type locality, approxi- mately 10 mi SW El Salto, Durango, Mexico); Dixon, 1969, Contributions in Sci., Nat. Hist. Mus. Los Angeles County 168:1-30; Robinson, 1979, Contributions in Sci., Nat. Hist. Mus. Los Angeles County 319; 1-13. 1 mi W La Laja (approximately 6 mi SE Mojara- chic), 1 (BYU 168.53). Zweifel (1954) reports two hatchlings (7 mi SW Lagunita, MVZ 59138, and 3 mi N Rio Verde, MVZ 59139) taken 30 June and 3 July 1953. Dixon (1969) lists the following locali- ties: Mojarachic (UMMZ 117756); 15 mi S, 6 mi E Creel (KU 44262-63); 2 mi W Sa- machique (KU 47429, 51324-25); 7 mi SE El Vergel (MVZ-1). The reviews by Dixon (1969) and Robinson (1979) not only provide a summation of the characteristics of this subspecies but also es- tablish relationships that were not possible for lack of specimen material in previous studies (Taylor 1935, Tanner 1958). Furthermore, ar- eas of distribution have been generally estab- lished for the subspecies of £. brevirostris and those species related to this group. A review of my field notes indicates that there were few if any differences in the habi- tats in which the specimens of £. b. bilineatus and E. parviauriculatus were found. Both were taken in open areas on a southwest slope in rocky terrain and at approximately the same elevation. Robinson (1979:5, Fig. 2) also cited this sympatric distribution. If one accepts as valid the distribution map of £. caUicephalus (Lieb 1985), then three species {caUicephalus, brevirostris, and parviauriculatus) are sym- patric in the Maguarichic-Mojarachic region of southwestern Chihuahua (see Lieb 1985). Family Teidae Genus C ne^nidophorus In Chihuahua, members of this genus are abundant and during the daytime are one of the more conspicuous lizards in the state. Only the genus Sceloporus appears to be more widespread and abundant. Within Chi- huahua there are seven species of the genus Cnemidophorus as listed below. In addition, C neomexicanus may occur in the north cen- tral area (Maslin and Secoy 1986:21), C. burti sticto^rammus approaches or enters Chi- huahua from northeastern Sonora or south- eastern Arizona, and C. g. septcmvittatus is reported for the northeastern corner (Duell- man and Zweifel 1962, Maslin and Secoy 1986). A.xtell (1961) reviewed the status of C. inornatus and described the population in northwestern Coahuila and northeastern Chi- huahua as a new subspecies, C. i. heptagram- mus. The synonymies of the various species and subspecies reported for Chihuahua are long and have been a source of confusion for many years. During two decades (1950 to 1970) much of the taxonomic confusion that previ- ously clouded our imderstanding of the sys- July 1987 Tanneh: Lizards AND Turtles OF Chihuahua 413 teniatic and taxononiic relatioiisliip of the spe- cies of Cnemidophorus in nortliern Chi- liuahua and tlie adjoining states has l)een largely resolved. Only a better understanding of distribution, life history, and ecological re- lationships apparently remains. The discovery of all-female species in the areas of south central United States (primarily Arizona, New Mexico, and Texas) and north central Mexico (Sonora, Chihuahua, and Coahuila) led to an intensive study of the genus in the above and adjoining areas (Lowe andZweifel 1952, Lowe 1956, Maslin, Beidle- man, and Lowe 1958, Maslin 1962, Smith, Williams, and Moll 1963, Zweifel 1965, Wright and Lowe 1965, Axtell 1966, Lowe and Wright 1966, Wright and Lowe 1967, Williams 1968, Walker 1981, and others). At present, three parthenogenetic species are known to occur in northern Chihuahua (exsanfiuis, uniparcns, and tessdatus) and perhaps a fourth if the range o{ neomcxicanus extends across the border from New Mexico as indicated by Maslin and Secoy (1986). Vance (1978) also plots (map, Fig. 6) neomexi- canus reaching to the northern border of Chi- huahua. It is now obvious that the phenotypic char- acters were not adequate to provide a com- plete understanding of the systematics of the various sympatric populations. The studies of Lowe and Wright, particidarK' their "Evolution of Parthenogenetic Species of Cnemidophorus — 1966," brought into focus the genetic foundations which served to clar- ify the parental background of the unisexual species. A better understanding of this genus in Chihuahua must wait for an in-depth inves- tigation of its species, particularly in the cen- tral and northern areas of the state. In recent studies by Cole (1985), Walker (1986), and others cited by them, the taxo- noniic problems associated with the unisexual (parthenogenetic) entities in the genus Cne- midophorus are discussed. Inasmuch as there are basic unresolved judgments concerning the proper system of names to be applied to these populations, I have retained them as species, recognizing their yet undetermined taxononiic status. In this study their distribu- tion in Chihuahua is the main reason for citing them. The recent publication "A Checklist of the Lizard Genus Cnemidophorus (Teidae)," by the late T. Paul Maslin and Diane M. Secoy (1986), provides a complete listing of the spe- cies and subspecies of the genus as well as synonymies, holotype and type localities, general range designations, and useful re- marks. This study will undoubtedly serve as a starting point for future studies of this wide- spread and diverse American genus. Cnemidophorus costatus barrancorum Zweifel Cncmidopiiorus costatus hundncuriim Zweifel, 1959, Bull. Amer. Miis. Nat. Hist. 117:57-116; Duell- nian and Zweifel, 1962, Bull. Amer. Mus. Nat. Hist. 123;1.57-210. Urinus Axtell, 1961, Copeia 1961(2): 148- 1.58. 2 mi N Gallego, 9 (UTEP ,3496-.3.502, .3512-13). Axtell described the west central (western Coahuila and eastern Chihuahua) populations as C. i. heptagrammus. Wright and Lowe (1965) redescribed C. /. arizonae in eastern Arizona, and Williams (1968) described as new the southern populations (Durango and northern Zacatecas) as C. i. pauhdus. The distribution of C. /. heptagrammus in Chi- huahua is not as yet fully determined. Present records are from an area west from Coahuila to or near Highway 45 and south of Ciudad Juarez along the highway to El Saiiz. I have no records for northwestern Chihuahua where inornatus may occur either as the subspecies heptagrammus or arizonae . Those Chihuahua specimens I have seen have GAB 58-62, ventrals 37-39, femoral pores (total) 32-35, and 7 complete body stripes in all but one, in which the median is only a faint, incomplete stripe for a short dis- tance posterior to the parietal. Other charac- ters are within the parameters set forth in the original description. Cnemidophorus uniparens Wright & Lowe Cntnni(loi)horus uniparens Wright and Lowe, 1965, Jour. Arizona Acad. Sci. .3(3):164-68. July 1987 TANNER: Lizards AND Turtles OF Chihuahua 415 6. 1 mi (by road) NE Janos, 1 (UTEP 3570). 14.7 mi (bv road) SVV Ricardo Flores Magon, 1 (UTEP 3572). 19.3 mi (bv road) ESE Ricardo Flores Magon, 4 (UTEP 3573-76). 6.2 mi (by road) W El Sueco, 2 (UTEP 3577-8). It appears that C uuiparcns may be sym- patric with C. exsangiiis in local areas. The distribution of the species in northern Chi- huahua will need a careful study before an understanding of the distribution of the uni- sexual species of northern Chihuahua is achieved. Cnemidophorus marmoratus marmoratus Baird & Girard Cnemiciopliortis marmoratus Baird and Girard, 1852a, Proc. Acad. Nat. Sci. Philadelphia, p. 128. Cnemidophorus tigris marmoratus. Burger, 1950, Chicago Acad. Sci. Nat. Hist. Misc. 65:7. Cnemidophorus marmoratus marmoratus Hendricks and Dixon, 1986, Te.xas J. Sci. 38(4):327-402. 21.5 mi N Ascension, 1 (BYU 14508). 30 mi (bv road) S Ciiidad Juarez, 1 (BYU 15208). 36 mi (by road) S Ciudad Juarez, 3 (BYU 15204-6). .5 mi S Las Palomas, 2 (UTEP 3410-11). 4.7 mi S Samalayuca, 2 (UTEP 3472-3). 24 mi NNE Ascension, 1 (UTEP 3567). Burger (1950) diagnosed marmoratus by color pattern and superciliary granules as fol- lows: dorsal color pattern a reticulum of sev- eral broken light stripes usually evident mid- dorsally and with vertical bars frequently accentuated on the sides; chin white or gray- ing with black spots; belly white, checkered anteriorly with gray and black. The supercil- iarv granules may extend to the first supraocu- lar'(Fig. 8). Zweifel (1959) added the following scale patterns for two series of specimens: granules around bodv, 26 specimens from Coahuila, 87-110 (x '= 100.2), and for Ala- mogordo, New Mexico, 15 specimens, 91-116 (x = 102.5). Six specimens from Chi- huahua have 88-108 (x = 97.8). For the same populations the femoral pores are as follows: 38-48 (x = 43.6), 40-48 (x = 45.3), and those from Chihuahua 41-46 (x = 44.0). The color pattern in adults is not a clearly defined striped pattern and may exhibit a vari- ation of broken stripes to irregular undulating spots on the body. At or near the nape, and extending from the head, stripes may be dis- cerned for a short distance. I have made no attempt to define the diflPer- ences in either the color or scale patterns between the two sympatric species, C. mar- Fig. S. Dorsal head scales of Cnemidophorus tigris marmoratus (BYU 14508) from 21.5 mi N Ascension, Chihuahua. moratus (and C. tigris) and C. tesselatus. However, it is obvious that there is a great similarity which perhaps misled Burt (1931), and thus his C. tesselatus included a com- posite. An understanding of this complex was not fully resolved until the distinction of uni- sexual and bisexual species was established (Zweifel 1965). Cnemidophorus marmoratus reticuloriens Hendricks & Dixon Cnemidophorus tigris pidcher Williams, Smith, and Chrapliwy 1960, Trans. Illinois Acad. Sci. 53:43-45. Cnemidophorus marmoratus reticuloriens Hendricks and Di.xon, 1986, Texas J. Sci. 38(4):327-402. 33 mi (by road) S Chihuahua City, 1 (BYU 15812). The above specimen is included by Hen- dricks and Dixon (1986) in the series with the subspecies reticuloriens, and yet it has a color pattern that approaches C. m. pulcher. The throat and chest are heavily pigmented and the venter is a dark brown. The gulars, though sooty brown, do have large dark spots unlike those in more northern marmoratus. The dor- sal and lateral body pattern is without recog- 416 Great Basin Naturalist Vol. 47, No. 3 nizable stripes and consists of dark to light brown reticulations. A series of dark vertical bars extend from the enlarged ventrals dorsad to the dorsal reticulations, a pattern similar to that of C. m. marmoratus. The scale characters are as follows: dorsals 94, GAB 95, femoral pores 20-21 (41) with 3 scales separating them, enlarged ventrals in 8 rows, ventrals 42 from gular fold to preanals, supralabials 5-5, infralabials 6-6, supraocu- lars 4-5 with posterior scale on left side di- vided, circumorbitals only to suture of second supraocular, interparietal single and with two rows of enlarged scales posterior to it, no frenocular, two suboculars with the anterior one enlarged, extending anteriorly and curv- ing dorsad to lie below and in front of the eye, dorsals from occiput to base of tail 202. The distribution of C. mannorotiis and its subspecies is not as yet fully understood. This single specimen, although placed in the sub- species reticiilohens, does not fit well into the description set forth by Hendricks and Dixon (1986). The color pattern is similar to the sub- species m. pulcher in that the gulars have large dark spots occupying at least half the gular area, the venter is mostly dark brown, and the dorsum is without recognizable lines. This specimen (BYU 15812) appears to be an intergrade between reticidoriens and pul- cher, but with strong indications that it is close to the latter. At least the influence of m. pulcher seems to extend north of the type locality in southeastern Chihuahua into the desert areas to the north and perhaps into the Balson Mapimi. Cnemidophorus tesschitus (Say) Ameiva tesselata Say, 1823, Long Expedition to Rocky Mountains 2:50. Cnemidophorus tcssehittis: Smith and Burger, 1949, Bull. Chicago Acad. Sci. 8:282; Zvveifel, 1965, Amer. Mus. Novitates 22.35:1-49. Smith, Williams, and Moll (1963) reported 62 specimens between Julimes and Alamo along the Rio Conchos. Specimens from this area were studied by Zweifel (1965) and re- lated to populations in central New Mexico. Zweifel's illustration in Figure 2-E from So- corro County, New Mexico, is very similar in dorsal (and lateral) color pattern to an adult female specimen of C. m. marmoratus taken in northern Chihuahua (BYU 14508). In the latter specimen the stripes are interrupted from near the shoulders posteriorly, and the sides of the body have a series of 12-13 verti- cal bars between the legs. There are 102 gran- ules at midbody; 41 total femoral pores; cir- cumorbital scales reach anterior to half of the second supraocular, a condition equal to class III in Figure 5, p. 17, of Zweifel (1965). In other scale patterns the mesotychials are en- larged but the postantebrachials are only slightly enlarged; fourth supraocular small, with a small scale preceding the first supraoc- ular; S-V length 94.5 mm. The demonstration that C. tesselatus is a unisexual species served to clarify the system- atics of a large group within the genus. The fact that C. tigris and C. tesselatus have indi- viduals, in some populations, with very simi- lar scale and color patterns may have induced Burt (1931) to include the widely dispersed figri.sasasynonymofC. tesselatus. Except for the small dark spots widely dispersed on the venter of female C. m. »ifln?jorofi/.s' from Chi- huahua, little color pattern difference seems to exist between these sympatric species. The distribution in Chihuahua is not known beyond those specimens reported above. Family Anguidae Genus Barisia Barisia levicoUis Stejneger Barimi levicoUis Stejneger, 1890, Proc. U.S. Nat. Mus. 1.3(809): 184. " Gerrhonottis imhricatus levicoUis Dunn, 1936, Proc. Acad. Nat. Sci. Philadelphia 88:368. Barisia levicoUis. Tihen, 1949, Univ. Kansas Sci. Bull. 33(1):2478. Barisia imhricatus . Guillette and Smith, 1982, Trans. Kansas Acad. Sci. 8.5(l):13-.32. Chuhuichupa, 1 (BYU 1.3898). 16 mi NE San Juanito, 1 (BYU 17023). We did not find Barisia to be numerous. Both specimens were found on hillsides in a shrub habitat, and both were moving when first observed. The Chuhuichupa specimen is a female, 145 mm in snout-vent length, with an incomplete tail. Both specimens were taken in low shrub, brushy habitat and not on rocky hillsides. This type of habitat is not an easy collecting area and may account for the few specimens taken, not only by us, but by others. The name usage here follows Tihen (1949) and Smith (1986). For additional records see Guillette and Smith (1982). July 1987 Tanner: Lizards andTurtles of Chihuahua 417 Genus Gerrhonotus GcrrJionotus hingii kingii (Gray) El of Ameiva tesselata Sav. Bidl. Chicago Acad. Sci. 8(13); 277-283. Smith. H M , .-vnoP S. Chrapuwy 1958. New and note- worthy Mexican herptiles from the Lidicker col- lection. Herpetologica 13: 267-271. Smith, H. M , .\nd L E. L.M'FE 1945. Mexican amphibi- ans and reptiles in the Texas Cooperative Wildlife collections. Kansas Acad. Sci. Trans. 48(3): 325- 354. Smith, H M , .and L \V IUmsev 1952. A new turtle from Te.xas. WassmannJ. Biol. 10(1): 45-54. Smith, H. M , and E H Taylor 1950. An annotated checklist and ke\' to the reptiles of Mexico exclu- sive of the snakes. U.S. Nat. Mus. Bull. 199. 253 pp. Smith, H M , K L Wh.liams, and E O Moll 1963. Herpetological explorations on the Rio Conchos, Chihuahua, Mexico. Herpetologica 19(3): 205- 215. Stejneger. L 1890a. Annotated list of reptiles and batra- chians collected by Dr. C. Hart Merriam and Vernon Bailey on the San Francisco Mountain, plateau and desert of the Little Colorado, Arizona, with descriptions of new species. North American Fauna No. 3: 103-110. 1890li. On the North American lizards of the genus Barissia of Gray. 1893. Annotated list of the reptiles and batrachians collected by the Death \'alley Expedition in 1891, with descriptions of new species. North .'\merican Fauna 7(2): 162-164. 1916. A new lizard of the genus Sccloponis from Texas. Proc. Biol. Soc. Washington 29: 227-230. Tanner, W. W 1957. A new skink of the multivirp.(itus group from Chihuahua. Great Basin Nat. 17: 111-117. 1958. Two new skinks from Durango, Mexico. Great Basin Nat. 18(2): 57-62. 1986(1985). Snakes of Western Chihuahua. Great Basin Nat. 45(4): 615-676. Tanner. W W . and W G Robison, Jr 1959. A collection of herptiles from Uricjue, Chihuahua. Great Basin Nat. 19(4): 78-82. 1962. A new name for a Chihuaiuia lizard. Her- petologica 16(2): 114. Taylor. E H 1933, New species of skinks from Mexico. Proc. Bio. Soc. Washington 46: 175-182. 1935. A taxonomic study of the cosmopolitan scin- coid lizards of the genus Eumcccs with an account of the distribution and relationships of its species. Univ. Kansas Sci. Bull. 23: 1-643. Taylor, E H., and I W Knobloch 1940. Report on an herpetological collection from the Sierra Madre mountains of Chihuahua. Proc. Biol. Soc. Wash- ington 53: 125-130. Thomas. R A . and J R Di.xon 1976. A re-evaluation of the Sccl(>))onis scalaris group (Sauria: Iguanidae). Southwestern Nat. 20(4): 523-536. Tihen, J A 1948. Two races of £/g«/7« kin^ii Gray. Trans. Kansas Acad. Sci. 51(3): 299-301. 1949. A review of the lizard genus Barisia. Univ. Kan.sas Sci. Bull. 33(1, no. 3): 217-256. 1954. Gerrhonotine lizards recently added to the American Museum (collection, with further revi- sions of the genus A/;»"()«ia. Amer. Mus. Noviates, Bull. 1687: 1-26. Troschel, F 1850 (1852). Cophosaurus texanus neue Eidechsenattimg aus Texas. Arch. Naturgesch. 16(1): 185, 388-394. Van Devender, T R , andC H Lowe 1977. Amphibians and reptiles of Yepomera, Chihuahua, Mexico. J. Herpetology 11(1): 41-50. Vance, T 1978. A field key to the whiptail lizards (genus Cnenicloplionts). Part 1: The whiptails of the United States. Bull. Maryland Herp. Soc. 11(6): 95-98. Walker, J M 1981. Systematics of Cfu'/d/f/op/ion/.s- gu- laris. I. Reallocation of populations currently allo- cated to Cncmicluphonts ^ttUarie and Cnemi- (lophonis scahiris in Coahuila, Mexico. Copeia 1881:826-849. 1986. Tlie taxonomy of parthenogenetic species of hybrid origin: cloned hybrid populations of Cne- midophonis (Sauria: Teiidae). Syst. Zool. 35; 427-440. Webb. R G 1962. A new alligator lizard (genus Ger- rhonotus) from western Mexico. Herpetologica 18(2): 73-79. 1970. Genhonotiis kin^ii . Cat. Amer. Amph. Rept. 97.1. Wiegmann, a F 1828. Beytrage zur Amphibienkunde. Isis von Oken 21(3-4): 364-383. 1834. Herpetologia Mexicana sen descriptio ani- phibioriun Novae Hispaniae. Pars Prima. Sauro- rum species. C. G. Luderitz, Berolini. 54 pp. Williams, K L 1968. A new subspecies of the Teiid lizard Cncmiilophorus inornatiis from Mexico. J. Herpetology 1(1-4): 21-24. Williams, K L , H M Smith, and P Chrapliwy 1960. Turtles and lizards from northern Mexico. Trans. Illinois Acad. Sci. 53: 36-45. Wright, J W . and C H Low e 1965. The rediscovery of Cneinicluphorufi arizonae Van Denburgh. J. Ari- zona Acad. Sci. 3(3): 164-168. 1967. Hybridization in nature between partheno- genetic and bisexual species of whiptail lizards (genus Cncniidophorus). Amer. Mus. Novitates 2286; 1-36. ZwElFEL, R G. 1954. Notes on the distribution of some reptiles in Mexico. Herpetologica 10; 145-149. 1959. Variation in and distribution of lizards of western Mexico related to Cnemidophorus sacki. Bull. Amer. Mus. Nat. Hist. 117; 57-116, figs. 1-6, pis. 45-49, tables 1-4. 1965. \ariation in and distribution of the unisexual lizard, Cnemkluphunis tcs.sclatus . Amer. Mus. Novitates 2235; 1-49. DRY-YEAR GRAZING AND NEBRASKA SEDGE {CAREX NEBRASKENSIS) Raymond D. Ratliff' and Stanley E. Westfall' Abstract — In 1984 (a dry year), Tiile Meadow, in the Sierra National Forest, California, was well grazed after several years of light use. This situation provided the opportunity to study responses of Nebraska sedge (Carex nebraskensis), an important forage species in mountain meadows, to protection and grazing. Rooted shoot frequencies and densities in fall 1984 and spring 1985 were the same within an exclosure and on the grazed area. Residual herbage (shoot weight) in fall and shoot heights in spring were greater within the exclosure. Lower spring shoot heights on the grazed area may relate to fall regrowth and reduced insulation induced by grazing. Nitrogen and potassium content of fiill herbage was greater on the grazed area. Phosphorus content was the same both inside and outside the exclosure. Nebraska sedge {Carex nebraskensis) is found from Kansas to California and from New Mexico to Canada (Hermann 1970). It is gen- erally palatable to cattle and horses. A valu- able species on many mountain meadows, Ne- braska sedge is often grazed heavily during summer. However, at Tule Meadow (Sierra National Forest, California) grazing of Ne- braska sedge and the meadow as a whole is largely controlled by weather. Under average conditions, Tule Meadow has a wet center and relatively dry edges. In wet years only the edges of the meadow re- ceive significant use, although cattle occasion- ally wade out to graze on preferred parts of specific plant species. In dry years all parts of the meadow receive significant use. From 1979 to 1983 catde grazed mainly along the edges of Tule Meadow, leaving most of it un- grazed or lightly grazed. Earlier, Pattee (1973) reported that cattle spent 100% of their time on the edges. Cattle grazing Tule Meadow had made sub- stantial use of Nebraska sedge by mid-July 1984. By the end of August no ungrazed patches of meadow remained (Fig. I). By Oc- tober surface water was present only at the lowest point — a very rare occurrence. At Wishon Dam, a few miles east of Tule Meadow, precipitation in 1984 totaled 76 cm, only 50% of the 1977-1985 average (152 cm). In addition, monthly maximum and mean air temperatures from January through Septem- ber were higher than the 1977-1985 average. We took advantage of this extraordinary condition of dryness to ask how grazing in such a year would affect Nebraska sedge. Would shoot frequencies, shoot densities, shoot heights, residual herbage weights, and nutrient contents be the same inside a live- stock exclosure and outside where grazing had occurred? Could grazing in a dry year benefit the Nebraska sedge population by stimulating vegetative reproduction? Methods and Materials Study area. — Tule Meadow, in the mon- tane zone at an elevation of 2, 170 m, is a basin type with vegetated margins (Ratliff 1985). It lies in a swale formed by lateral moraines (Wood 1975) and usually has surface water all year. Beneath the sod an organically rich top- soil extends to depths of 90 to 120 cm. Soil texture ranges' from sand to silt loam. Inor- ganic, gleyed material extends to 275 cm. In 1979 we established an exclosure in a lotic Nebraska sedge site (Ratliff 1985). Within the exclosure we studied seasonal biomass trends, Nebraska sedge moiphology, carbohydrate levels (Steele et al. 1984), and shoot life history (Ratliff 1983). Except for the life history plots, the exclosure has been undisturbed since fall 1981 and has returned to prestudy conditions. Sampling. — We randomly located points on grid systems. Inside the exclosure we lo- cated 60 points on a half-meter grid within a 238-m" area. In the remainder of the Nebraska sedge site, about I ha, we located 120 points on a 1-m grid. Independent sets of grid points were selected for fall (3 October 1984) and 'Pacific Southwest Forest and Range Experinifiit Station, Forest Service, US. Department otAgricnlture. 2()f5l E. Sierra Ave , Fresno, California 93710. 422 July 1987 Ratliff, Westfall: Nebraska Sedge 423 Fig. 1. Tule Meadow, Sierra National Forest, California, showing extent of grazing by cattle in 1984. spring (16 May 1985) sampling. Quadrats (10 x 20 cm) were centered at the grid points. Presence or absence of Nebraska sedge shoots in the quadrats was noted. Rooted frequency (% presence) was com- puted for fall and spring samples. In fall, cur- rent mature shoots (vegetative and reproduc- tive) and juvenile shoots (shoots with three or fewer leaves unfolded) of Nebraska sedge were counted to estimate shoot densities. The shoots were then cut off at the surface to esti- mate residual herbage weights. The herbage was oven-dried (24 hrs at 60 C) and weighed. Total nitrogen (N), phosphorus (P), and potassium (K) in the shoot material was estimated at a commercial laboratory. Analysis procedures were N — Kjeldahl nitro- gen, P — nitric, perchloric acid digestion, and spectrometry, and K — hydrochloric acid di- gestion and spectrometry. Some grazed quadrats did not contain sufficient Nebraska sedge for the chemical analyses; therefore, materials from up to four randomly selected, grazed quadrats were combined. In spring, close observation was required to distinguish the previous year's mature vegeta- tive shoots from the rapidly expanding younger shoots. Also, surface water depth precluded efficient cutting of shoots. There- fore, all live shoots of Nebraska sedge rooted in the quadrats were counted, and the height of the tallest one was measured. Statistics. — We took advantage of current conditions of weather and grazing; replication of treatments was not possible. Differences between the exclosure and the grazed area should therefore not be extrapolated to other sites. Nevertheless, the comparisons provide new insight on response of an important meadow species, Nebraska sedge, to grazing. For each data set we computed the 95% confidence intervals for the means. In the case of frequencies the confidence intervals were for the proportions of quadrats with Nebraska sedge. The hypothesis of no difference be- tween analogous characteristics was rejected when the 95% confidence interval for the dif- ference (grazed area vs. exclosure) covered zero. Standard methods of calculation (Steel and Torrie 1960) were used. Fall and spring values were not compared since different kinds of data were involved. Also, reproductive shoots included in the fall sample died before spring. Total shoot densi- 424 Great Basin Naturalist Vol. 47, No. 3 Table 1. Means and confidence intervals for Nebraska sedge shoot frequency, density, residual herbage weight, height, and nutrient content and differences under grazing and protection at Tule Meadow, Sierra National Forest, California. Treatment Difference Grazed Protected (G - P) Measure x + cr X + CI a + ci'' Frequency (%) Fall 1984 91 ± 5 82 ± 10 9 ± 11 Spring 1985 91 ± 5 88 ± 8 3 ± 10 Density (shoots/m~) Fall 1984 Total 380 ± 63 357 ± 76 23 ± 103 Mature 274 ± 46 266 ± 56 8 ± 75 Juyenile 106 ± 22 91 ± 24 15 ± 35 Spring 1985 296 ± 44 231 ± 47 65 ± 69 Weight (g/nr), fall 1984 62 ± 11 172 ± 43 -111 ± 33 Height (mm), spring 1985 144 ± 7 198 ± 14 -54 ± 13 Nutrients (%), fall 1984 Crude protein' 6.31 ± 0.41 5.48 ± 0.28 0.81 ± 0..50 Phosphorus 0.11 ± 0.01 0.11 ± 0.01 0.00 ± 0.01 Potassium 1.33 ± 0.09 1.00 ± 0.04 0.33 ± 0.11 "95% confidence intervals for proportions and means ''95% confidence intervals for differences 'Nitrogen (%) x 6.25 ties between fall and spring were therefore expected to be different. Results and Discussion Frequency. — In 1984, grazing did not af- fect rooted frequencies of Nebraska sedge shoots in the 10 x 20 cm quadrats (Table 1). The diflferences in proportions of occupied quadrats in the exclosure and in the grazed area in fall and spring were no more than expected by chance. All observations com- bined, Nebraska sedge frequency was 88.9% ± 3.2%. Juvenile shoot frequency in the fall was nei- ther enhanced nor reduced by grazing. The frequencies were 67% ± 12% inside and 68% ± 8% outside the exclosure. Density. — Greater density on the grazed area could occur if grazing stimulated tiller and rhizome production. However, grazing in 1984 did not affect densities of Nebraska sedge shoots (Table 1). Nevertheless, interpreting the confidence interval, we are 95% confident that the maxi- mum possible differences in fall were —80 shoots per m" (23 — 103) to 126 shoots per m" (23 + 103) more on the grazed area. Differ- ences of such magnitudes, based on the aver- age weight per shoot in the exclosure, trans- late to -0.8 AUM/ha and 1.3 AUM/ha; thev could influence grazing management. An AUM (animal unit month) is the amount of forage required by a mature cow with calf for one month (Range Term Glossary Committee 1974). We are also 95% confident that the maximum possible differences in spring were -4 shoots per m' to 134 shoots per m" more on the grazed area. A difference in the magni- tude of the upper confidence limit could influ- ence composition of the current forage crop. Confidence intervals for mature and juvenile shoots may be similarly interpreted. Residual herbage. — As expected, resid- ual herbage of Nebraska sedge was greater (78 to 143 g/m") inside than outside the e.xclosure (Table 1). Residue outside in 1984 averaged 36% (24 to 56%) of that inside. Use of Ne- braska sedge therefore averaged 64%. Leav- ing just 62 g/m" on the grazed area every year would not maintain site productivity. The total amount of residual herbage should, however, be adequate to maintain productivity even with 64% use of Nebraska sedge each year. For the elevation of Tule Meadow, Ratliff et al. (1987) estimated that residual herbage should average 1,740 kg/ha for good condition wet meadows. Nebraska sedge is not the only species in the stand. Assuming equal use of all species and average production (474 g/nr in 1980-1981), we would expect residue outside the e.xclosure to July 1987 Ratliff, Westfall: Nebraska Sedge 425 total about 170 g/m" (1,700 kg/ha). Shoot heights— In spring, Nebraska sedge shoots within the exclosure were 41 to 67 mm taller in mean height than those out- side (Table 1). Two explanations for this differ- ence are offered. First, initiation ol regrowth followed by cold weather may lower the car- bohydrate reserves on the grazed area. This would lower the carbohydrate levels available for, and thereby slow, spring shoot growth. Second, grazing removes dead vegetation that insulates the soil surface and overwintering shoots. Insufficient insulation may keep tem- peratures below those needed for growth longer and thereby slow spring shoot growth. By the time growth was completed in 1985, shoots looked equally high outside and inside the exclosure. If really the same, growth out- side had to accelerate more than growth in- side. Less shading of new growth outside by old leaf tissue could produce such an effect. Nutrients. — Concentrations of both nitro- gen and potassium were greater in the resid- ual herbage on the grazed area, but phospho- rus concentrations were no different (Table 1). Residual Nebraska sedge herbage on the grazed area still contained sufficient protein for cow maintenance. Herbage inside the ex- closure was deficient in protein. Mean crude protein concentration (N% x 6.25) in residual herbage was between 0.3 and 1.3% more out- side than inside the exclosure. Inside the ex- closure the upper confidence limit for crude protein content was 5.8%. Outside the exclo- sure the lower confidence limit for crude protein content was 5.9%; the upper limit was 6.7%. Dry, pregnant, mature cows (the ex- pected condition as the grazing season ends) require 5.9% protein in their diet (Church 1984). Phosphorus concentrations were deficient for cow maintenance both inside and outside the exclosure. Diets of dry, pregnant, mature cows should contain at least 0. 18% phospho- rus (Church 1984). Potassium requirements for cows are from 0.5 to 0.7% (Church 1984). Therefore, resid- ual herbage inside and outside the e.xclosure has ample potassium for cow maintenance. Nevertheless, the difference in potassium be- tween the exclosure and the grazed area is biologically significant. Potassium tends to concentrate in growing plant tissue (Black 1957, Church 1984). Higher potassium con- centration in shoots from the grazed area sug- gests greater fall growth outside than inside the exclosure. Fall growth could negatively affect carbohydrate reserves needed for win- ter respiration and early spring growth. Conclusions By altering grazing patterns, weather at Tule Meadow appears to offset adverse effects of grazing on Nebraska sedge. Grazing in the 1984 dry season did not stimulate vegetative reproduction but did slow shoot growth the following spring. Shoot frequency and density were little affected, however, suggesting that occasional seasons of significant herbage re- moval have no lasting effects. After grazing, less abundant, but more nu- tritious, forage is available for animals using the Nebraska sedge site in fall. Availability of nutritious fall forage may benefit wild herbi- vores, especially in dry years. Grazing of Nebraska sedge should aim to remove excessive amounts of old leaf tissue and promote growth of new, photosyntheti- cally efficient tissue. Management plans for grazing Nebraska sedge should, nevertheless, include end-of-season regrowth periods to as- sure ample carbohydrate reserves for winter respiration and initial spring growth. LiTER.'^TURE Cited Black. C A 1957. Soil-plant relationships. John Wiley & Sons, New York. Church, D C 1984. Livestock feeds and feeding. 2d ed. O & B Books, Corvallis, Oregon. Herm.\nn, F J 1970. Manual of the carices of the Rocky Mountains and Colorado Basin. USDA, Forest Service, Agriculture Handl)ook 374. .397 pp. P.^TTEE, O H 1973. Diets of deer and cattle on the North Kings deer herd summer range, Fresno County, California: 1971-1972. Unpublished thesis, Cali- fornia State L'niversity, Fresno. R\NCE Term Glossary Committee 1974. A glossary of terms used in range management. 2d ed. Soc. for Range Manage., Denver, Colorado. RATLIFF, R D 1983. Nebraska sedge (Carex nehraskensis Dewey): observations on shoot life history and management. J. Range Manage. 36: 429-430. 1985. Meadows in the Sierra Nevada of California: state of knowledge. U.S. Forest Service, Pacific Southwest Forest and Range Experiment Station, General Technical Rept. PS\V-84. 52 pp. R\TLiFF, R D . M R George, and N K McDougald. 1987. Managing livestock grazing on meadows of California's Sierra Nevada ... a manager-user guide. Univ. of California, Division of Agric. and Nat. Res., Leaflet 21421. 9 pp. 426 Great Basin Naturalist Vol. 47, No. 3 Steel. R G D., and J H Torrie 1960. Principles and 37: 465-467. procedures of statistics. McGraw-Hill, New York. Wood. S H 1975. Holocene stratigraphy and chronology Steele. J M . R D Ratliff. and G L Ritenour 1984. of mountain meadows. Sierra Nevada, California. Seasonal variation in total nonstructural carbohy- Unpublished dissertation, California Institute of drate levels in Nebraska sedge. J. Range Manage. Technology, Pasadena. DIAMOND POND, HARNEY COUNTY, OREGON VEGETATION HISTORY AND WATER TABLE IN THE EASTERN OREGON DESERT Peter Ernest Wigand' Abstract — Cores obtained in 1978 from Diamond Pond, Diamond Craters, Harney County, Oregon, as part of the Steens Mountain Prehistory Project, provide a record of vegetation change on the sagebrush/shadscale ecotone and of local and perhaps regional water tables. Pollen, macrofossils, sediments, and charcoal from these radiocarbon-dated cores were analyzed. Varying abundance of juniper, grass, sagebrush, and greasewood pollen, and of aquatic to littoral plant macrofossils reflects changing regional effective moisture and local water table since 6000 B. P. Eleven dates spanning 5200 radiocarbon years and four regionally correlated volcanic ashes establish the dating of seven periods of diflferent moisture regimes; 1. Greasewood and saltbush pollen dominance before 5400 B.P. indicates shadscale desert. Rapid accumulation of alternating silts and medium sands lacking aquatic plant macrofossils and pollen reflects periods of ephemeral ponds with water table 17 m below the present level and considerable erosion of maar slopes, 2. Increasing sagebrush pollen from 5400 to 4000 B. P. indicates sagebrush expansion into shadscale desert. Scirpus, Riimex, Ceratophyllum. and Polygonum pcrsicaria macrofossils and finely laminated clayey silts evidence perennial pond. 3. From 4000 to 2000 B.P. abundant juniper and grass pollen reflects extensive juniper grasslands (juniper seeds from trees growing nearby fell into the pond during this period). Rising charcoal values indicate greater importance of fire. Deepest late-Holocene pond ca 3700 B.P. corresponds with postulated intensive human occupation of northern Great Basin marsh and lake locales. 4. Between 2000 and 1400 B.P. increased sagebrush pollen mirrors reduced effective moisture and reexpanding sagebrush steppe. More abundant Scirpus and Rumcx macrofossils evidence shallow pond. 5. From 1400 to 900 B.P. more numerous grass pollen indicates returning greater effective moisture resulting in deeper water with abundant Potainogeton. 6. About 500 B.P. increased greasewood and saltbush pollen evidences drought. Ruppia seeds and pollen and the mollusk Musculium indicate shallow, brackish water. 7. Abundant juniper and grass pollen reflects moister conditions between 300 and 150 B. P. Numerous Ceratophyl- lum fruits indicate deeper, freshened water. Since the mid- 1800s man and changing climate have encouraged sagebrush reexpansion. Increased Scirpus macrofossils indicate shallower water. Although topographic diversity creates the of Malheur and Harney lakes during the past variety of habitats found in the Great Basin, 160 years. volcanic eruptions, tectonic activity, and Diamond Pond in the Diamond Craters sharp variations in climate, lasting 100 to 200 area of the southern Harney Basin, Oregon, is years, have affected the size and diversity of an ideal location to watch changing vegetation these habitats (Mehringer 1986, 1977). Cli- patterns for three reasons. First, Diamond matic change in the Great Basin, especially in Pond lies adjacent to and at the same elevation the north, is best reflected in its fluctuating as Diamond Swamp (Figs. 2, 3), and its water lakes and marshes (Mehringer 1986). level is controlled by groundwater discharge. Since early in 1826 when Antoine Sylvaille Second, varying abundance of aquatic and lit- and five other trappers entered the Harney toral plant macrofossils reflects the expansion Basin ofsouthern Oregon (Fig. 1) and reached and contraction of the fringe of littoral and the river later named for him — the Silvies emergent aquatic species that presently sur- River (Rich etal. 1950)— the volumes of Mai- round Diamond Pond (Fig. 3). Finally, heur and Harney lakes have varied consider- changes in the shadscale, lower sagebrush, ably (Piper et al. 1939). Accounts from early and juniper communities that adjoin on por- trappers, descriptions by early settlers, and tionsofDiamond Craters (Fig. 2) are reflected records maintained by local, state, and federal in the detailed microfossil record of vegeta- agencies reveal dramatic changes in the levels tion change unparalleled in the northern Department of Anthropology, Washington State Universit\ , Pullman, Washington 99102. 427 428 Great Basin Naturalist Vol. 47, No. 3 MOUNTAINS S T I N K I N 0 WATER R I D a E Fig. 1. The Harney Basin of southeastern Oregon Ues nortliwest of Steens Mountain. The 1,2.50-m (4, 100-ft) contour is 1.2 m below the higliest beach ridge of Phivial Lake Mallieur and 4., 3 m below the drainage divide in Malheur Gap to the south fork of the Malheur River (Piper et al. 19.39:18). July 1987 WiGAND: Diamond Pond 429 Fig. 2. Diamond Craters, Harney Count}', Oregon, with it.s major geological features and vegetation associations. Great Basin. At Diamond Pond both pollen and macrofossils provide sensitive proxy data of climatic change in the Harney Basin. Historical Lake Level.s Early accounts of the sizes of Harney and Malheur lakes vary considerably, due in part to the time of year when the valley was vis- ited. The Hudson s Bay Company trappers that explored and trapped the Snake River country usually passed through the Harney Basin either in early summer when seasonal runoff was greatest or in late fall when lake levels would be at their yearly low. The lakes were first described on 31 Octo- ber 1826, when Peter Skeene Ogden, chief trader of the Hudson's Bay Company, and 35 men descended the Silvies River and discov- ered two lakes separated by a "ridge of land about an acre in width." A freshwater lake (Lake Malheur) about 1 mi wide by 9 mi long lay east of a salty lake (Harney Lake) about 5 mi wide bv 10 mi long (Davies et al. 1961:19-22)' The "Sylivills River" (Silvies River) and two other small streams fed the freshwater lake, while another small river (Sil- ver Creek) flowed into "Salt Lake." On 7 June 1827 Ogden returned to the Harney Basin and found the lakes much higher than in the previous fall and had to detour northward to avoid the flooded basins 430 Great Basin Naturalist Vol. 47, No. 3 ■•.«-*- •'^■vv" X**S Fig. 3. Diamond Pond viewed from the northwest with the westernmost dome of Diamond Craters hehind it (W. Bright photo, September 1978). (Davies et al. 1961:125-127). On 18 and 19 June 1829 he ascribed a length of 20 mi (33 km) and a width of 15 mi (25 km) to "Sylvailles Lake" and a similar size to "Salt Lake" (Harney Lake) (Williams et al. 1971:160). A narrow ridge of land a few feet wide separated the lakes. These dimensions are larger than the basins that contain these lakes today. Ogden's successor, John Work, camped next to "Sylvailles Lake" (Malheur Lake) on 2 July 1831 and reported in his journal that the lake "was unusually high" and very brackish (Haines 1971:132). By 1833 maps of the area published by the London mapmaker, A. Arrowsmith, showed a chain of three lakes called the Youxpell Lakes (possibly Harney, Mud, and Malheur). Subsecjuently, the lake that was mistakenly thought to drain into the Malheur River was named Lake Malheur. On 7 July 1859 Captain Henry D. Wallen reported "a large salt lake" — 20 mi long by 9 mi wide. Wallen named it "Lake Harney" in honor of General Harney, who was comman- der of the military district of the Columbia (Clark 1932:lll-il2). Again these dimen- sions are much larger than the basin that con- tains Lake Harney. Despite the exaggerated accovmts of Ogden and Wallen, Piper et al. (1939:22) suggest that prior to 1864 Malheur Lake may have been relatively small. Since then Malheur Lake has nearly dried at least three times and has reached to or slightly beyond the meander lines of the official 1875 land surveys just as many times. According to various accounts, after three years of very low rainfall and runoff Lake Malheur was almost to- tally dry in 1889, and again in the fall of 1917 it was relatively small (Piper et al. 1939). July 1987 WiGAND; Diamond Pond 431 1,000.000.000 CAPACITY (CUBIC METERS) 2 .000.000.000 3.000.000 .000 Spillover level into Ihe Malheur R 40.000 60.000 80.000 WATER SURFACE AREA (HECTARES) Fig. 4. Relationship of lake depth, .surface area, and volume in the Harne\' Basin. At 1,254 m (4, 1 14 ft) Malheur Lake would discharge into the south fork of Malheur River through Malheur Gap (Piper et al. 1939:18). Desiccation beginning in 1921 culminated during the 1930s. In 1930 and 1931 no water ran into Malheur Lake from the Silvies River and very little from the Donner und Blitzen River. The lake began receding, and bv Sep- tember 1930 it covered onl>' 810 ha (2,000 ac) (Fig. 4), and a year later only 203 ha (500 ac). In 1932 it still received no water from the Silvies River, but renewed flow from the Don- ner und Blitzen filled it to the 1,247-m (4,092- ft) level covering about 10, 120 ha (25,000 ac). Excepting thermal springs on the lakebed, Harney Lake was dry during these three years. In 1934 both lakes were dry, and ranch- ers and farmers cut hay on the exposed bed of Malheiu- Lake (Ferguson and Ferguson 1978:17, 109). Again in 1966 through 1968 the lakes were almost drv (Walker and Swanson 1968:L13). Large lakes characterized the late 1870s to earlv 1880s and recurred between 1895 and 1905 (Piper et al. 1939). In 1921 the lakes rose briefly before the extremely low levels of the 1920s and the total desiccation of the mid- 1930s. After 1935 the lakes refilled and reached peak levels during the 1950s (Walker and Swanson 1968:L13). In early spring of 1984 the basins filled to form a lake some 60,700 ha (150,000 ac) in extent and, in places. over 10 m (30 ft) deep (Braymen 1984). At the 1984 rate of rise, with each meter increase in water depth covering an additional 11,290 ha (27,890 ac), the lake would have reached the 1,250-m (4,103-ft) level bv June of 1985 and covered an area of about 81,000 ha (200,000 ac). However, drought conditions during the first half of 1985 and again during the first six months of 1986 and 1987 reversed this trend. Fluctuating lake levels meant displacement and financial "boom or bust for farmers and ranchers (Braymen 1984, Ferguson and Fer- guson 1978:29-30, Crick 1983). Changing lake size and water chemistry dramatically affected both the extent of the marsh adjoin- ing Malheur Lake and the flora and fauna within it (Piper et al. 1939:23). Study Area The Landscape Diamond Pond (SWl/4, Sec. 30, T28S, R32E, Diamond Swamp Quadrangle, Ore- gon) is a 2-m-deep, 46-m-wide perennial pond (Figs. 2, 3). It fills 92-m-wide Malheur Maar, an explosion crater, to within 9 m of the rim. The maar is located on the westernmost dome of the 67-km" Diamond Craters Volcanic Complex at 1,265-m elevation. To the south- 432 Great Basin Naturalist Vol. 47, No. 3 west the confluence of Kiger, McCoy, and Swamp creeks and the Donner und Bhtzen River form a broad, marshy floodplain. Dia- mond Swamp. The steep, east-facing side of fault-blocked Jackass Mountain lies to the west across the valley (Fig. 1). Northward stretches the Harney Basin with the broad expanses of the Malheur Marshes; beyond lie the rugged Strawberry Mountains. To the southeast is Steens Mountain (2,961 m) with its usually snow-covered crest 32-48 km from the craters. Diamond Craters, first described by I. C. Russell (1903:54-57), is situated near the southern end of the Harney Basin, a 13,727- km" area of large-scale, post-Miocene subsi- dence into underlying magma chambers (Walker 1979:5-6). The craters consist of six major and one minor structural domes that range in height from 50 to 120 m and comprise an area over 9 km in diameter, which exhibits a variety of volcanic features (Peterson and Groh 1964, Brown 1980:12). Surface drainage from the surrounding up- lands collects in the north central part of the Harney Basin in two large, marsh-surrounded lakes periodically joined at the Narrows (Fig. 1). At its greatest extent in May and June, Malheur Lake typically extends 26-29 km eastward from the Narrows and is about 13 km across and up to 3 m deep (Waring 1909:11). When the water level in Malheur Lake ex- ceeds 1,247.1 m (4,091.5 ft), it spills through the Narrows into Mud Lake. At 1,247.7 m (4,093.5 ft), Mud Lake overflows westward at Sand Gap into 11-13-km-wide Harney Lake (Piper et al. 1939:20-21). Although Harney Lake's depth may change up to a meter or more annually, its area is less variable because it lies in a steep-sided basin. Silver Creek supplies Harney Lake from the northwest, whereas Malheur Lake re- ceives runoff from the north through the Sil- vies River and Poison Creek (Piper et al. 1939; Hubbard 1975). To the south the Donner und Blitzen River and its tributaries originate on Steens Mountain where, during uplift and later Pleistocene glaciation, it eroded deep canyons in the gentlv dipping basalts (Russell 1903:17, 1905:84-85, Smith 1924, Fuller 1931:38, Hansen 1956:14, Bentlev 1970:21, 67, 1974:213, 217, Mehringer 1985a:Fig. 12). Between Frenchglen and Diamond Craters the Donner und Blitzen River flows north- ward for 30 km through a verdant marshland from 0.5 to 5 km wide. North of Diamond Craters near Voltage it discharges into Lake Malheur (Fig. 1). Climate The topography of Harney Basin is the ma- jor factor influencing local climate. Elevation varies from 1,250 m on the valley floor to between 1,370 and 2,740 m in the surround- ing uplands. The Harney Basin receives most of its precipitation from winter and spring storms derived from the marine air that flows into the Pacific Northwest (Fig. 5). Weather Bureau records collected since the late 1800s indicate that the Harney Basin as a whole is semiarid, but the Blue Mountains to the north and Steens Mountain to the south can receive up to three times the average regional precipi- tation. Snow, which accounts for about one- third of the annual precipitation, may fall on the valley floor between October and June and on the mountains in any month. The aver- age annual total varies from 115 cm (45 in) at Burns to 64 cm (25 in) at the Harney Branch Experiment Station and 84 cm (33 in) at Dia- mond. Daily and seasonal temperature range is wide, relative humidity is low, evaporation is great (about 4.8 times the annual rainfall; Piper et al. 1939), and the number of cloudless days per year averages about 120. The grow- ing season varies from 80 days at the Harney Branch Experiment Station to 117 days at Burns. Although during the last 80 years an- nual mean temperature below 1,280 m (4,200 ft) in Harney Basin has averaged about 7.8 C (46 F), differences result from the peculiari- ties of local circulation. At Burns (1,267 m) over a 76-year period the mean January tem- perature was -3.8 C (25.1 F), and the mean July temperature was 19.8 C (67.6 F). The extremes ranged between —36 and 39 C ( — 32 and 103 F). Strong prevailing winds come from the southwest throughout the year, but especially during March through June (Mar- tin and Corbin 1931, Sternes 1960, U.S. De- partment of Commerce, Weather Bureau 1954-1984). Lake levels in the Harney Basin depend primarily upon the discharge of its four major streams (Fig. 6) and groundwater recharge (Russell 1903:29); however, they also mirror total precipitation. Precipitation amounts in July 1987 WiGAND: Diamond Pond 433 HARNEY BASIN CATLOW ALVORD VALLEY VALLEY 1980s 1970s 1960s 1950s 1940s 1930s Squaw Butle Voltage 1920s 1910s 1900s ku-J lU Harney Branch Experiment Station 1890s 1880s ^ 1870s 1860s Camp Harney RAINFALL ( CM ) J tjl W J 3 N A A A U E O N R Y L P V U C V T E AH EM R MB Y BE E R IkJ ■^-*"-— — *- 4i Mameur Buena Vlata a Alvord Refuge • ■ Rancti Juniper ^ Lake bJuihlikLi^Jj Am Ul P Ranch Hart Mtn Sunrfse Refuge Valley Blltzen Juniper Andrews Ranch lU Camp Warner Fig. 5. Decadal means (e.g., 1971-1980) for monthly rainfall in the Harney Ba.sin .since the 1860s. Monthly averages for the 76-year Burns, Oregon, rainfall record are illustrated in the figure key (bottom center). 434 Great Basin Naturalist Vol. 47, No. 3 SILVER CREEK/ ' I ' 1940 "^ \ ' 19 60 1980 1 900 1920 YEAR A . D . Fig. 6. Stream discharge records, expressed as percent of the mean tor all years of record for major streams of the Harney Basin. the Harney Basin and the Catlow Valley to the tween 20 and 30 cm (8 and 12 in) a year in the south show similar trends during the last 80 Harney Basin. Recording stations along the years (Fig. 7). Annual rainfall averages be- western edge ofthe basin average about 30 cm July 1987 WiGAND: Diamond Pond 435 Paulina Burns Camp Harney 5.. 50 -L 0 Diamond ^ Camp Warner B li t z e n Voltage /Malheur Refuge Headquarters Harney Branch Experiment Station Frenchglen I \ \ \ 1860 1880 1900 1920 1940 YEAR A . D . 1960 1980 Fig. 7. Rainfall in the Harne\' Basin and the Catlow Valley expressed as a percentage of long-term means. The northernmost stations are at the top. (12 in) annually, whereas stations located in the north central part of the basin average closer to 20 cm (8 in) annually. Vegetation The terrestrial flora of the Harney Basin reflects the environmental restrictions of a dry climate and thin, volcanic, often saline soils. Distribution of local plant communities varies according to characteristics of soil (depth, pH, and moisture), site (slope, aspect, and eleva- tion), and temperature. On the surrounding mountains plant species from the Rocky Mountains, the Cascades, the Sierras, and the mountain ranges of the Great Basin combine with endemic species to form characteristic plant comiuunities (Price 1978). A transect between Diamond Craters and the top of Steens Mountain cuts across at least six distinct vegetation zones that have been 436 Great Basin Naturalist Vol. 47, No. 3 *.;^*~** ♦ft,«^> "^^V • ^ Fig. 8. View northward toward the lava flows northeast of Diamond Craters. The area between Northeast Dome and White Lake (upper right) has the densest stands of juniper on Diamond Craters (P. Wigand photo, June 1980). studied and variously named during the past 30 years (Hansen 1956, Faegri 1966, Urban 1973, Mairs 1977). Generally, these zones from lowest to highest are: (1) the Shadscale Zone dominated by Sarcobatus vermiculatus (black greasewood), Atriplex spinosa (spiny hopsage), and Atriplex confertifolia (spiny saltbush); (2) the Lower Sagebrush Zone dom- inated hy Artemisia tridentata var. tridentata (big sagebrush) but with abundant Chrysothomnus nauseosus (gray rabbit- brush), C. viscidiflorus (green rabbitbrush), Tetradymia glabrata (littleleaf horsebrush), and T. canescens (gray horsebrush); (3) the Juniper Zone characterized hy J uniperus occi- dentalis; (4) the Aspen Zone with both Pop- ulus tremidoides (quaking aspen) and Cerco- carpus ledifoliiis (mountain mahogany); (5) the Upper Sagebrush Zone dominated by Artemisia tridentata var. vaseyami; and (6) the Subalpine Grassland (Mehringer and Wigand 1987:Fig. 4). Of these, the Shadscale, Lower Sagebrush, and Juniper zones occur at Diamond Craters. The Shadscale Zone occupies thin, stony soils on the south and west sides of West Dome (Figs. 2, 3). The Lower Sagebrush Zone covers most of Diamond Craters and supports, in addition to the dominant shrubs, a variety of grasses, including Stipa comata (needle-and-thread grass), Stipa thurheriana (Thurber's needle-and-thread grass), and Bromiis tectorum (cheatgrass). The Juniper Zone covers the low-lying lava flows north of North Dome (Figs. 2, 8). Big sagebrush, Holodiscus dumosus var. glabrescens (gland ocean-spray), Ribes cereum (squaw currant), Ribes aureiim (golden currant), rabbitbrush, ferns (in moist crevices in the lava flows), and native bunchgrasses, primarily Agropyron spicatum (bluebunch wheatgrass), grow among junipers that, according to counts of tree rings collected by personnel of the Bu- reau of Land Management (BLM), are up to 200 years old. Diamond Pond lies within the ecotone be- tween shadscale and lower sagebrush commu- nities on Diamond Craters. The terrain east and south of Malheur Maar is dominated by big sagebrush and its associates. North and west of the maar black greasewood and spiny hopsage intermingle with big sagebrush, July 1987 WicAND: Diamond Pond 437 littleleal horsebrush, Tetradipiiia spinusa (spiny horsebrush), and some Artemisia spinescens (bud sage). Growing among the shrubs are Leptodactylon piin<:,cn.s (prickly phlox), Chaenactis duu^lasii var. acJiilleaefo- Ua (dusty maiden), and tidytips {Laijia ^landii- losa). Within Malheur Maar aspect determines whether shadscale or big sagebrush commu- nities predominate. Whereas the south-facing slope supports spiny saltbush, some spiny hopsage, and an occasional big sagebrush or green rabbitbrush, the east- and north-facing slopes are covered by green rabbitbrush and big sagebrush interspersed with hopsage and occasional spiny saltbush. The west-facing slope consists of a talus with a few big sage- brush and bunches of giant wildrye (Ehjmiis cineiTus). A single golden currant survives in the shade offered by the cliflF on the north- facing slope of the maar. Between the shrubs of the south-facing slope are Amsinckia tesseJlata (tessellate fiddleneck), Cnjptontha circumscissa (matted cryptantha), C njptantha torretjana (Torrey's cryptantha), and Astragalus lentiginosus (freckled milkvetch). A dense blanket oi Dis- tichlis striata (alkali saltgrass) and bunches of bora.\ weed {Nitrophila occidentalis), saltwort {Glaux maritiina ), and poverty weed {Iva axil- laris) thrive on the lower slope close to the water s edge. Bromus tcctorum (cheatgrass) occurs throughout the maar. Onjzopsis Jiymenuides (Indian ricegrass) and Sitanion hystrix (bottle- brush s(iuirreltail grass) are locally abundant along the northwest rim of the maar, and tufts of Muhlenbcrgia asperifolia (alkali muhlen- bergia) and pockets of the exotic grasses, Bro- mus japonicus (Japanese bromus) and Afiro}}yron cristatum (crested wheatgrass), occur sporadically on the slopes of the maar. Growing close to the western and north- western margins of the pond are stands of European and native weeds. Urtica dioica ssp. gracilis var. angustifolia (stinging nettle) and Lcpidium latifolium (pepperwort) pre- dominate, with some Cirsium arvense (Cana- dian thistle), Epilohium minutum (willow- herb). Aster frondosus (short-rayed aster), Solidago occidentalis (western goldenrod), and in open, sunny areas Potentilla anserina (common silvei-weed) and Chenopodium al- bum (pigweed). In the moist ground at the water's edge and in the shallow water of the pond's margins grow Bumex umrititmts (golden dock). Ranun- culus cynibalaria {shore buttercup), Veronica anagallis-aquatica (water speedwell), and Juncus balticus (Baltic rush). Typha latifolia (common cattail) lining the northern and western margin of the pond is broken by a stand ofPhragmites communis (common reed) on the northeast shore. Along the north shore the cattails are enclosed by a stand of Scirpus acutus (hardstem bulrush) that dominates the southern, western, and northern shores of Di- amond Pond. Thick growths of Ceratophyl- lum demersum (hornwort) and Potamogeton pectinatus (sego pondweed) clog the pond. Methods In June 1978 a crew that included Dr. P. J. Mehringer, Jr., K. L. Petersen, myself, and members of the Steens Mountain Prehistory Project summer field school began coring near the center of Diamond Pond. Dr. Mehringer and students from the Depart- ment of Anthropology's fall 1978 palynology class completed coring in late October of the same year (Fig. 9). We obtained 14.97 m of core with a modified Livingston piston corer (Gushing and Wright 1965) that was operated from a drive tower anchored to a wood and styrofoam raft. Overlapping cores were collected for the top 5.45 m. After collecting each core in 3-m-long, 10-cm-diameter bar- rels, we cut them to the actual length of sedi- ment recovered, capped them, and returned them to cold storage at Washington State University. Prior to description and sampling, we ex- posed the sediments by cutting the barrels lengthwise with a rotary saw, thereby avoid- ing distortion of sediments by extrusion. Gores were correlated by distinctive strati- graphic markers, especially volcanic ashes, and by depth. Generally, our sediment de- scription adhered to Soil Survey Manual (Soil Survey Staff 1951) except that boundary dis- tinctness followed Mehringer and Sheppard (1978). We determined color (moist and dry) with the Munsell Soil Golor Ghart (1975). Sediments with recurrent series of texture differences are denoted as laminae, whereas sequences of similar texture but different color are denoted as bands. 438 Great Basin Naturalist Vol. 47, No. 3 Fig. 9. WSU Department of Anthropology palynology class coring Diamond Pond (October 1978). View is to the southeast. Far slopes are dominated by sagebrush. Hardstem bulrush {Scirpus acutiis) and cattail (Typha latifolia) are visible in the foreground. Before sampling the cores for micro- and macrofossils, we removed 11 radiocarbon and 4 tephra samples to establish a regional se- quence of dated volcanic ashes (Mehringer et al., in preparation). Microfossil sampling in- terval was determined by depth, sediment type, boundary location, and apparent age. Several replicate samples were collected from each of 312 levels by removing a 1 x 1 x 2-cm block (2 cm ) with a wire frame cutting device (Kolva 1975:Fig. 6), or, in a few cases where this was not possible, sediments were packed into a round-bottomed scoop with a volume of 2. 3 cm^ (Fletcher and Clapham 1974, Barthol- omew 1982:15). We used one replicate sam- ple from each level for microfossil analysis and another to determine dry weight and organic and carbonate carbon percentages by weight loss on ignition at 600 and 950 C (Dean 1974). Pollen extraction generally followed Mehringer (1967:137); after acetolysis the samples were mounted in silicone oil (2000cs). To estimate the number of microfossils per volume of sediment, we added 10 commer- cially prepared tablets, each containing 10, 850 ±200 Lifcopodium spores (batch no. 006720) (Stockmarr 1971, 1973), and weak HCl to all but 24 samples as the first extraction procedure. The 24 samples, from near the top of the sequence, were extracted as part of a pollen class project in fall of 1978. Ten tablets, each containing 12,500 ±500 Lycopodiwn spores (batch no. 212761), were added to each of these samples. Using 400X magnification, I counted 96 samples from Diamond Pond with a range of 406-2,937 terrestrial pollen (mean 949 ±543) and 104-3,281 Lijcopodiiim tracers (mean 612 ±456) (Fig. 10). With the addition of aquatic pollen tvpes and spores, counts range from 436 to 3,359 (mean 1,135 ±577). When the algae are added, the number of micro- fossils per sample ranges from 471 to 4,400 (mean ca 2,000). In a few cases the algae were so abundant that their numbers had to be approximated from the number of algae ob- served while counting at least 200 Ly- copodium tracers. In addition, two sizes of charcoal. Charcoal A (25-50 microns) and Charcoal B (> 50 microns), were counted. July 1987 WiGAND: Diamond Pond 439 DIAMOND POND Lycopodium Counted 0 1000 Terrestrial Pollen Counted 0 1000 2000 Terrestrial Pollen cm' (with 95% confidence intervals) 3000 0 100,000 200,000 300,000 400,000 ^^ •' - L 'Z Tephra I w " n ^ ^ 4C_ y *■ ^^ \ , ^ b^ ^ Fig. 10. Number oi Lycopodium tracers and terrestrial pollen counted per sample and the population estimates of terrestrial pollen (pollen sum) per cubic centimeter of sediment. As a standard procedure during analysis of the Steens Mountain lakes, at least 50 grains each of grass, sagebrush, saltbush, grease- wood, and pine pollen were counted because they were to be used in ratios providing im- portant clues to the history of steppe vegeta- tion. Often the number of pollen grains counted was determined by attaining at least 50 grass pollen. After sampling for microfossils, we cut one complete sequence of cores into sections cor- responding to stratigraphic units or, when stratigraphic units exceeded 15 cm, into equal subdivisions of the unit not longer than 15 cm. We used two-thirds of each of these samples for macrofossil analysis and the other one- third for sediment analysis. One hundred and thirty-five macrofossil samples of known volume (determined by dis- placement of water) were washed through four nested, stainless steel screens (8, 10, 28, and 42 meshes per inch). Initially, I separated the residue by size and removed the most obvious seeds and shells. Later, using a dis- secting microscope, I sorted the still-moist fractions and identified macrofossils bv com- paring them with the seed and plant collec- tions of the Laboratory of Anthropology and the Marion Ownbey Herbarium, Washington State University, and standard texts (Martin and Barklev 1961, Berggren 1969, Mont- gomery 1977, Katz et al. 1965, Musil 1978). After identifying the macrofossils, I dried them for storage and future radiocarbon dat- ing. Shells of the moUusks Lijmnaea pahistris, Planorhella subcrenata, Gyraulus parvus, Gyraulus crista, and Miiscidiiim seciiris were identified by Dr. Dwight W. Taylor. Following routine pretreatment to remove carbonates (hydrochloric acid) and organic matter (hydrogen peroxide) (Black 1965:559, 562), I employed wet screening and hydrome- ter methods to divide 33 sediment samples at 0.5-phi intervals into 26 size classes ranging from -2.0 to 11.0 phi (Krumbein 1934). The resulting cumulative weight percentage curve was used to determine mean, median, sort- ing, skewness, and kurtosis (Folk and Ward 1957). I entered all data on computer files for statistical analyses and computer plotting. To facilitate presentation and discussion of the 440 Great Basin Naturalist Vol. 47, No. 3 LU 6.0 — 2 X 8.0 Radiocarbon Oat* A S a m p I • • ZONE 3 T a p hr a RADIOCARBON AGE BP Fig. 11. Pollen samples with respect to depth, radio- carbon age B. P. , and pollen zones. micro- and macrofossils, I subdivided the dia- grams into zones by using a cluster analysis program that joined only neighboring samples or adjacent groups into a dendrograph (Orloci 1967, Petersen 1981:45-46). Both to summarize and illustrate major changes in the micro- and macrofossil records, I plotted ratios of specific plant species by radiocarbon age. Ratios selected for Diamond Pond and other Steens Mountain lakes use the most abundant pollen types, usually from plants that characterize the vegetation zones of the Harney Basin and Steens Mountain. These ratios were calculated as a standard procedure for comparison of the microfossil data for all Steens Mountain Project pollen counts. All pollen and charcoal ratios pre- sented were smoothed using a three-level weighted average, (a+2b-^c)/4 (Holloway 1958). Results Dating and Deposition Rate Eleven radiocarbon determinations and four regionally correlated tephras from Dia- mond Pond cores establish a chronology span- ning the last 5500 years B.P. and provide a basis for the deposition rate curve (Fig. 11). Except between ca 4500 and 1500 B.P. when deposition slowed, sediment has accumulated rapidly .since 6200 B.P. Modern Ceratophijllum demersum from Diamond Pond dating 126 ±1.6% modern (VVSU-2529) agrees with postbomb modern samples of the last six years or so (Baker et al. 1985). This indicates that groundwater sup- plying Diamond Pond today does not contain old carbonates that might result in erroneous radiocarbon dates. Sediments Diamond Pond deposits above 11.4 m (ca 5450 B.P.) primarily consist of dark, lami- nated, fine silty clay rich in organic detritus and well-preserved macrofossils (primarily seeds and snail shells). Laminated inorganic clays, silts, and sands with occasional lenses of sandy fine gravel containing angular and spherical clay clasts characterize sediments below 11.4 m. Grain size analyses of 33 sediment samples from Diamond Pond indicate occasional in- creases in sand content resulting in a much coarser median and mean grain size, poorer sorting, and more positive skewness (Fig. 12). Above 11.4 m sediments with finer mean and median grain size reflecting increased silt and clay content are typical. Characteristically, these sediments are less positively skewed, better sorted, and more leptokurtic than those below 11.4 m. However, at least three units of coarser sediment interrupt these finer deposits. Organic and Carbonate Content Plots of weight loss on ignition of 312 sam- ples (Fig. 13) show a gradual increase in or- July 1987 WiCAND: Diamond Pond 441 2 3 2 40 SO 0 80 94 0 20 40 60 Fig. 12. Sediment parameter.s and proportions ot gravel, sand, silt, and clay. DIAMOND POND WEIGHT (GRAMS CM"') 0.0 I 0 WEIGHT LOSS AT WEIGHT LOSS AT 600°C (%) SSCC (%) 20 2 34 0 20 40 60 0 5 10 Fig. 13. Weight loss on ignition (first a.\is), and organic carbon (second axis) and carbonate (third axis) percentages from 312 samples from Diamond Pond. Note that organic carbon weight on the first axis is the difference between weight loss at 950 C and weight loss at 600 C. 442 Great Basin Naturalist Vol. 47, No. 3 r R~ '? ^^ V-' i* »■ «' 'j" ^ •? 0^ <;* V J**/ V* o' ^ a ^^ C' ']' ■f" l" o 50 microns and plotted it as a percent of total pollen. Pollen ZONES. — Three pollen zones, based upon the eight most common terrestrial plant pollen types (Pinus, Juniperus, Aiiemisia, Gramineae, Sarcohatus, other Chenopodi- ineae, Tubuliflorae, and Umbelliferae), are apparent in the dendrograph (Fig. 15). To eliminate the influence of aquatic and littoral plants on formation of the zones, they are excluded. In addition, the two lowest pollen July 1987 WiCAND; Diamond Pond 443 ^° f '' "^ ^ ^ / ~'^ ^' ///^ % POLLEN SU^ *POLLEN TOTAL Fig. 14 continued. samples, 12.9 m (ca 5800 B.P.) and 14.0 m (ca 6000 B.P.), were omitted from the sample set used for zoning beeause they contained pollen grains probably derived from Pliocene and Miocene deposits. Although other zone divi- sions are possible, the breaks at 7.25 and 5. 15 m (ca 3630 and 1750 B.P.) are the most obvi- ous and useful (Figs. 15, 11). Pollen accumulation rates. — From the average years per centimeter for each zone and estimates of the total microfossils per sam- ple, 1 calculated the number of microfossils deposited per square centimeter per year for each sample. Pollen accumulation rates for Zone 1 between 11.9 and 8. 1 m and in Zone 3 between 3.8 and 0.85 m are from 3 to 10 times larger than the average for Zone 2 (Fig. 16). More pollen is accumulating in the sediment than can be accounted for given the time rep- resented in Zones 1 and 3. Pollen accumula- tion rates for Zone 2 average about 10,000 pollen grains per cm^ per year, rather than the 33, 140 pollen grains per cm per year estimated for Zones 1 and 3. Rapid pollen accumulation in Zones 1 and 3 corresponds with major increases in Sorcobatus pollen percentages and of sand in the sediments of Diamond Pond. Macrofossils I recovered macrofossils of 16 plant genera, along with five species of mollusks and two species of ostracods, from Diamond Pond (Fig. 17). Plant macrofossils include the well- preserved seeds and occasional fruits of ter- restrial, aquatic, and littoral species. Shells of the mollusks Lymnaeo palustris, Planorbella subcrenata, Gyraidus parvus, Gyrauhts crista, and Musculiiim securis occur primarily in Zones 1 and 3 but were not found in the present aquatic vegetation (Fig. 17). Living Lymnaca pahistris were found in Cer- atophyUum dcmcrsum collected from Dia- mond Pond but were not recovered from within the sediments. The topmost macrofossil sample yielded a fish scale. Its ctenoid shape indicates that it came from a fish related to the sunfishes. The recently introduced largemouth bass has this type scale. In addition, 22 two- to three- millimeter-long, lunate-shaped objects, each with a hard enamel coating (perhaps teeth), were recovered from 9. 1 to 8.7, 7.8 to 7.7, 4.0 to 3.8 m, and in particular from a unit with crumb structure from 6.9 to 6.6 m. 444 Great Basin Naturalist Vol. 47, No. 3 DIAMOND POND ZONES 0 ■ ■ I...... 1-1,950 1,000 A.D. B.C. -1,000 CO < LjJ < z: LlI _J < -2,000 -3,000 -4,000 Fig. 15. Zoning diagram showing tlie clustering oi adjacent pollen samples plotted by age. Although numbers of plant macrofossils and mollusk shells vary dramatically from sample to sample, patterns of association and major trends are evident. Below 11.8 m (ca 5500 B.P.) plant macrofossils are absent; instead, some beds contain numerous aquatic insect parts. Especially abundant were members of the family Corixidae (water boatman), which feed on algae and other minute aquatic organisms. In general, variation in plant macrofossil abundance suggests that submerged aquatic plants, emergent aquatic plants, and littoral plants respond as groups (Table 1). It appears that although changes in the numbers of sub- merged aquatic plant macrofossils may be out of phase with variations in the abundance of emergent aquatic plants, the species within each group fluctuate in concert. July 1987 WiGAND Diamond Pond 445 POLLEN / CM 16,000 Fig. 16. Terrestrial pollen cm "/yr ' plotted by radio- carbon age. Depo.sition rates were determined from the first derivative of a fourth order polynomial fit of radio- carbon ages with depth (Fig. 11). Occasionally, both the seeds and pollen of certain plants occurred in Diamond Pond. To compare fluctuations in the abundance of the macrofossils of these species with changes in their corresponding pollen types, standard- ized macrofossil counts and pollen percent- ages as a percent of total pollen minus the six most abundant pollen types {Arte7nisia, Sar- cobatus, Juniperus, Gramineae, Pinus, and other Chenopodiineae) were plotted (Figs. 18, 19). Discussion Interpretation of the Pollen and Seed Record (Pollen, Macrofossils, and Ratios) Both long- and shori;-term trends in the pollen and macrofossil records are evident (Figs. 14, 17). Long-term trends are charac- terized by two patterns, one that crosscuts zone boundaries and another that corre- sponds to zone boundaries. Whereas percent- ages o( Piniis (pine), sagebrush, Cyperaceae, and other Potomop,cton pollen have increased since 6200 B.P., pollen values of greasewood have declined. Ratios of pine, sagebrush, and greasewood emphasize these trends (Figs. 20, 21). The second long-term pattern is charac- terized by a pronounced increase in pollen values between about 3800 and 2000 B.P. Pollen percentages of other Chenopodiineae (although it also shows a general decline in pollen values since 6200 B.P.), grass, and ju- niper were all significantlv larger at that time (Figs. 14, 20, 21). Charcoal abundance with respect to pollen sum also increases between 3800 and 2000 B.P. (Fig. 22). According to the Pearson product-moment correlation coefficient, both sizes of charcoal are positivelv correlated (r = 0.84069, significant at P = .0001). Additional ratios of Charcoal A, Charcoal B, and total charcoal to each of the major types of pollen repeat the same pattern of charcoal abun- dance. These long-term microfossil trends help characterize the pollen zones. Zone 1 is char- acterized by overwhelming abundance of greasewood pollen. Increasing percentages of sagebrush and relatively high percentages of juniper and grass and non-Sarcobatus Chenopodiineae pollen — probably Atriplex (saltbush) — are the hallmarks of Zone 2. In Zone 3 sagebrush pollen reaches its maximum abundance, whereas grass and juniper pollen percentages decline. Short-term deviations of 100 or 200 years' duration interrupt the general trends outlined above (Fig. 13). Usually these variations are minor, but occasionally significant change in pollen contribution is evident. In general, in- creases in greasewood pollen percentages are out of phase with sagebrush, grass, and ju- niper pollen percentages. Although grass and juniper pollen values usually vary in the same direction, in Zone 3 they are often out of phase. Greater pine pollen percentages gen- erally correspond with or immediately follow increases of juniper pollen percent. Generally, the numbers of submerged, emergent, and littoral macrofossils generally have declined since about 5500 B. P. (Fig. 23). Dramatic fluctuations in their numbers do not necessarily correspond to changes in the ratio of aquatic (submerged plus emergent) to lit- 446 Great Basin Naturalist Vol. 47, No. 3 0 10 0 10 0 10 100 0 10 0 10 tOOO F^C= )-" Fig. 17. Numbers of macrofossils recovered from Diamond Pond, standardized for 1,000 ml of sediment, are plotted on a log scale. toral macrofossils. The ratios of both aquatic (Potamogeton pectinatus, other Potamogeton, Polygonum persicaria, and Mijriophijllum) to littoral (Cyperaceae, Ttjpha, and Rumex) plant pollen and aquatic to littoral plant macrofossils reveal dramatic short-term fluc- tuations in the abundance of aquatic and lit- toral plants (Figs. 21, 23). Modern pollen rain. — The surface pollen studies of Davis (1981:Appendix 16, 1984: Fig. 3) and Henry (1984) in southern Idaho offer modern pollen comparisons for the fossil pollen record from Diamond Pond. Although Davis's Albion Mountain surface pollen per- centages do not "duplicate" environments of deposition in lakes and ponds, they provide several useful clues that help characterize past plant communities at Diamond Craters. These are: 1. Juniperus pollen in excess of 7% indicates that juniper was growing near or at the site. 2. Sarcobatus pollen in excess of 10% characterizes greasewood communities. 3. Artemisia values in excess of 50% characterize big sagebrush communities. 4. Other Chenopodiineae values in excess of 20% charac- terize shadscale communities. Because Diamond Pond is located in the ecotone between the shadscale and lower sagebrush zones, aspects of both communities influence the pollen assemblage. Except for grass and juniper pollen percentages between 4000 and 2000 B.P., values of the major ter- restrial pollen types at Diamond Pond have always been similar to those obtained from greasewood communities in the Albion Range (Davis 1984) and from the Terreton Basin of southeastern Idaho (Bright and Davis 1982). Grass and juniper pollen percentages from 3800 to 2100 B.P. and 1100 to 900 B.P. are comparable to those obtained from Davis's juniper and grassland communities, but the shadscale community pollen component is much stronger. Comparison of modern and fossil pollen val- ues suggests that plant communities that grew around Diamond Pond when juniper and grass pollen were most abundant have no modern analogue either in the Albion Range or at Diamond Pond. Fossil pollen evidence from Diamond Pond indicates that juniper and grass were part of the nearby shadscale community or that grass and juniper grew very close to greasewood- and saltbush- dominated areas. Juniper values of 8 to 12%, as well as radiocarbon-dated juniper from woodrat middens at Diamond Craters, indi- cate that juniper was growing in areas where it does not grow today (Mehringer and Wigand 1987, 1988). However, because the values of juniper pollen are on the low side of those July 1987 WiGAND; Diamond Pond 447 (t-^ .<'"" -4* ,0* ^t"- ,f'" 6^^ o5 .0"' ,ll^ u>^^ BO^^^ pu ,t"^" 0^^"' c '" po^ 0°. .«\\^ j\\* r p - ::::::;;;;:::: r__ s. ;;— iHul E= ; - kg^TEPHRA ^^^H II III ^ — IV -2000 -3000 4000 Fig. 17 continued. expected for modern juniper zones, the trees probably were more dispersed. Juniper, rainfall, stream discharge, and WATERTABLE. — ^Juniper growth, together with its relationship to effective precipitation, is complex and beyond the scope of this study. However, there is evidence that winter rain- fall may be critical in maintaining established juniper stands Qeppesen 1978) and that the May/June rainfall component may also be im- portant (Peter 1977:50-51). Between 1890 and 1910, 1940 and the early 1950s, when this rainfall component predominated, tree growth, as reflected in the tree-ring widths, was especially good (Peter 1977: Fig. 10). At the same time juniper stand establishment in northern California increased dramatically (Young and Evans 1981:Figs. 2, 3). One might conclude that in the past juniper expansion must also have reflected greater effective pre- cipitation. The historical correspondence of rainfall and increased stream discharge and higher lake levels in the Harney Basin is clear. Rain- fall records for the Harney Basin indicate that dry decades reflect low winter and spring rainfall and are characterized by decreased runoff" and shrinking lakes and marshes (Piper et al. 1939, Walker and Swanson 1968, Hub- bard 1975). High winter and spring rainfall Table 1. Aquatic and littoral species recovered from Diamond Pond. Scientific name Common name Submerged Aquatic Species CeratophyUum deinersiim Zatmichellia palustris Hippttris vulgaris MyriophijUum spicatum var. exalbescens Emergent Aquatic Species Potainogeton pectinatus Potanwgeton nutans Potamogeton pusiUus Potanwgeton other (broken P. pusiUus ?) Ranunculus aquatilis Ruppia maritiina Polygonum persicaria Polygonum sp. Littoral Species Scirpus acutus Car ex sp. Ranunculus sceleratus var. multifidus Ranunculus sp. Cicuta douglasii Rumex maritimus Terrestrial Species Juniperus occidentalis Atriplex confertifolia Suaeda sp. cf. Lupinus (Type C) Liguliflorae hornwort homed pondweed common mares-tail spiked water-milfoil sego pondweed broad-leaved pondweed small pondweed pondweed white water-buttercup ditch grass spotted smartweed smartweed hardstem bulrush sedge celeryleaved crowfoot buttercup western water-hemlock golden dock western juniper spiny saltbush seablite lupine 448 Great Basin Natur.\list Vol. 47, No. 3 I ..v^'^ oN^*" A\^'' ^i 12 0- SP>^ .'°^" .^r^' .V^ .6* ol-*' .o^^*' ft* .11* '> ...'•':>••• ...-'„.,.'•'• .x^^^ ..'■■ „.^-'>" '••;.'"' ,...'"'„..>'" p..'* ,,.•"•' ,.••• 0 20 40 0 10 0 20 0 10 0 20 0 10 100 0 20 40 60 80 0 10 100 lOOO 0 20 40 0 10 100 1000 r- Fig. 18. A comparison of pollen percentages (percent of total pollen exclnding the six most abundant terrestrial pollen types — Artemisia. Gramineae, Sarcobatus, Pimisjuiiipenis. and other Chenopodiineae) and numbers of macrofossils (standardized to 1,000 ml of sediment; Fig. 17). with increased runoff, and higher lake levels and expanded marshes characterize wet decades. This pattern has been aptly demon- strated during the last 10 years in the Harney Basin. It is evident that juniper spread several times during the past 4000 years into areas where it does not grow today (Mehringer and Wigand 1987, 1988). If this'was the result of increased precipitation, evidence for result- ing higher water tables should be reflected in the water depth fluctuations indicated by the plant macrofossil record from Diamond Pond. Higher water tables should correspond with increased juniper pollen values. Macrofossils and water table. — At Dia- mond Pond variation in assemblages of plant macrofossils can evidence changes in water depth resulting from (1) gradual or rapid infill- ing of the pond (reflected by the general suc- cession from submerged to emergent aquatic plants to littoral plants), or (2) periodic water table fluctuations (reflected by rapid changes in the dominance of one group or the other that may or may not reverse the general trend from submerged acjuatic to littoral species). If plant macrofossils were uniformly abundant throughout the deposits of Diamond Pond, a simple ratio of aquatic to littoral species should clearly reveal these variations. Deeper water would be reflected in greater abun- dance of submerged and emergent aquatic plant macrofossils at the expense of those from littoral species. However, the numbers of plant macrofossils vary greatly (Fig. 23). The number of seeds or fruits deposited in pond sediments is dependent upon the num- ber of seeds produced by the plant, how close it is to the place where the seeds are de- posited, the plant's height, and whether or not its seeds can float (Birks and Mathewes 1978). Before 5500 B.P. absence of seeds in the sediments of the maar indicates that there was no vegetation growing in the pond. Since July 1987 WiGAND; Diamond Pond 449 „vv*" .6^ ul- ■,«'" 50" ZONE 20 0 10 100 1000 0 5 0 ip 0 20 40 60 80 0 10 100 1000 0 20 0 Ip 100 1000 p 20 0 [0 Fig. 18 continued. the establishment of Diamond Pond, how- ever, an uninterrupted pollen record indi- cates that it never dried out. Reduced num- bers of macrofossils after 5500 B.P. could mean either that water depth in the pond had become so great that both aquatic and littoral plants had retreated to the margins of the maar and away from the center (the coring site), or that the species that were dominant could not disperse their seeds as well. Abundant plant macrofossils could mean the reverse. As water depth increased, one would ex- pect the number of seeds to decrease. How- ever, the number of aquatic macrofossils would increase in proportion to littoral macro- fossils not only because aquatic plants were closer to the center of the pond than littoral species, but also because there was more area for aquatic plant growth. As the water table dropped, one would expect greater macrofos- sil abundance and the proportion of littoral species should increase as they approached the center of the pond and reduced the area in which acjuatic plants could grow. Because at least 15 m of sediment has accu- mulated in Diamond Pond during the past 6000 years, the geomorphology of the maar probably has changed radically. The expected proportion of aquatic to littoral plants in a broad, shallow basin as Diamond Pond is to- day would have been quite different in the steep-sided, funnel-shaped maar of the past. Because the diameter of the pond was smaller then, the center of the pond would always have been closer to all the plant com- munities in the maar even when water depth was great. Therefore, even though the gen- eral scenario described above would hold, the number of seeds would have been relatively much greater. Likens and Davis (1975) call this phenomenon focusing . As the pond filled and became relatively much broader, one would expect the total number of macro- fossils to decrease. This is what we observe 450 Great Basin Naturalist Vol. 47, No. 3 Ceratophylluiu demersum fruits and leaf hairs CaratophyL fruits Caratophyl. leaf hairs Number of Fruits or Leaf Hairs 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 Radiocarbon Age B.P. Fig. 19. A comparison of the number oi Ceratophyllum demersum leaf hairs (expressed as percentage of the pollen sum) and the number o( Ceratophyllum demersum seeds (standardized to 1,000 ml of sediment; Fig. 17). Fig. 20. Smoothed (a+2b + c)/4 ratios of major pollen types, Part A. July 1987 WiGAND; Diamond Pond 451 1000 2000 30O0 4000 5000 6000 Fig. 21. Smoothed (a + 2b + c)/4 ratios of major pollen types. Part B. 1000 2000 3000 4000 5000 6000 Zone II Fig. 22. Smoothed (a + 2b + c)/4 ratios of total eharcoal. Charcoal A (25-50 microns), and Charcoal B (> 50 microns), to the pollen sum. (Fig. 23). However, the ratio of aquatic to closely mirrors the juniper pollen percentage littoral plants continues to reflect water depth curve suggests that it does reflect the water as it did in the past. The fact that this ratio table (Fig. 24). 452 Great Basin Natueulist Vol. 47, No. 3 Macrofossils 1000 1500 2000 2500 3000 3500 4000 <500 5000 5500 nadlocBrbon Age B P Fig. 2.3. Numbers of suhinergecl, fmcr^ent, and littoral macrofossils e.xpressed as percent of the .55()()-year mean (1 = 100% on the scale). Ratio of acjuatic (submerged and emergent) to littoral plant macrofossils (scale on the left is the proportion). The Environmental Record The record from Diamond Pond includes at least 6200 years, of which the period between 3600 and 2000 B.P. is revealed in detail unequaled in the northern Great Basin. Between 6000 and 5400 B.P. Sarcuhatus (greasewood) pollen dominated the micro- fossil record. Its extreme abundance, up to 75% of the pollen sum, indicates that Sarco- hatus (black greasewood) and other salt- bushes, most likely Atriplex confertifolia (spiny saltbush) and Atriplex spinosa (spiny hopsage), covered the floor and lower slopes of Harney Basin. The preponderance of Sar- cobatus pollen suggests that saline soils char- acterized the area (Branson et al. 1976). The periodic occurrence of aquatic insects, algae, and finer sediments indicates that occa- sionally Malheur Maar supported ephemeral ponds. However, the absence of aquatic plant macrofossils suggests that the ponds were never permanent enough to maintain a growth of aquatic plants. The pond surface was seasonally at least 15-17 m below the present water surface of Diamond Pond. Be- cause Diamond Pond acts as a standpipe for the local water table, such lowered water ta- bles suggest that marshes in the Harney Basin were greatly reduced in area and probably dry for much of the year. Intermittent beds of sands accumulated in Diamond Pond from the periodic erosion of the sparsely vegetated slopes of Malheur Maar. Sands and coarse silts washed into Diamond Pond along with pollen (Figs. 12, 25). Concentration of pollen from the slopes of the maar in sediments of the ephemeral shallow ponds at its bottom re- sulted in abnormally high pollen accumula- tion rates, especially in Zone 1 (Fig. 16). Clay clasts in many of the beds indicate intense but sporadic rainfalls. These data agree with the findings of others in the northern Great Basin concerning a dry mid-Holocene (Mehringer 1986, Davis 1982). On Steens Moimtain at Fish Lake abundant sagebrush with respect to grass pollen be- tween 8700 and 4700 B. P. reveals lower effec- tive moisture than before or after, and sage- brush to grass ratios at Wildhorse Lake indicate warmer temperatures (Mehringer 1985:Fig. 12). A dramatic and totally unparalleled in- crease (within the Diamond Pond record) of sagebrush pollen about 5300 B.P. indicates the first in a series of wet periods that herald the end of mid-Holocene drought. However, because this event follows closely the fall of the 5460 B.P. pumice, it is possible that the July 1987 WiGAND: Diamond Pond 453 POLLEN « JUHIfESUS GRAMINEAE A H T E It I S I A AQUATIC PLANT SEEDS LITTORAL PLANT SEEDS » CLAY Fig. 24. Summary diagram incliidiiig, from left to right: (1) smootlied juniper pollen percentage, (2) radiocarbon dates on juniper macrofossils from packrat midden.s, (3) smoothed ratio of grass to sagebrush pollen, (4) ratio of aquatic to littoral plant macrofossils, (5) percent of cla\- per sediment sample. pumice, by acting as a mulch, may have con- tributed to the spread of sagebrush. On the other hand, because the increase was short- lived, with greasewood soon the dominant plant again, it is more likely that a brief inter- val of greater effective moisture was the cause. By 5000 B.P. greasewood was in full retreat before the advance of other salt- bushes, sagebrush, and grass. They continued their slow spread at the expense of grease- wood until ca 3800 B. P. The appearance and sudden abundance of littoral and aquatic plant macrofossils and mollusk shells shortly before the fall of Tephra IV (5460 B.P.) indicate that Malheur Maar contained a relatively permanent body of wa- ter with lush aquatic growth. A marsh domi- nated by Scirpus acittus (hard-stem bulrush) and Rumex maritimiis (seaside dock) was quickly replaced by a permanent pond filled with a variety of aquatic plants, primarily Cer- atophyUum demersiim (hornwort). Poly- gonum pcrsicaria (spotted smartweed), Zan- nichellia palustris (horned pondweed), and Potamogeton pusillus (small pondweed), and surrounded by a littoral community still domi- nated by bulrush and dock. By 4-ioO B.P. the water table was within 10 m of its present level. Rising water table at Diamond Pond suggests that mid-Holocene drought had given way to effectively moister conditions. Resultant higher regional water tables would enable the Malheur Marshes to expand into areas formerly occupied by greasewood. This, together with the invasion of other saltbush and sagebrush communities into the upper reaches of greasewood- dominated areas, may explain the sudden drop in Sarcohatus pollen values. Between 3750 and 2050 B.P. increased grass and juniper pollen values reflect the spread of juniper and grass into sagebrush and shadscale communities around Diamond Pond (Fig. 24; Mehringer and Wigand 1987, 1988). Charcoal proportions greater than be- fore or after this period may evidence more frequent fires resulting from more abundant fuel. Low greasewood pollen values reflect the continued presence of marshes and salt- bush and sagebrush communities in areas pre- 454 Great Basin Naturalist Vol. 47, No. 3 100% SAND 50% \ / 50% (20 iXf. /''♦ — SHALLOW POND & MARSH 1 293 I410,» • • / ••1426 6? ^ 1487 • > • ' /• / , 1415 e'l029\l11d 468 , . 100% / \ . ^1443 '^V.* » '^ai ••669 SILT DEEP POND 1494 523 /\ 50% 100% CLAY Fig. 25. Proportions of sand, silt, and clay in Diamond Pond sediments and their relationships to water depth as suggested by plant fossils. Numbers indicate sediment depth in centimeters (Fig. 12). viously occupied by greasewood. From 3800 to 3600 B.P. high juniper and grass pollen values, also reflected in the pollen ratios, cor- respond to the greatest abundance of sub- merged and floating aquatic plants as com- pared to littoral species. The water table may have risen more quickly than the accumula- tion of sediment in Diamond Pond to make it deeper than at any other time. Proportions of clay in excess of 25% also suggest deep water (Figs. 12, 25). Throughout the Great Basin, rising lake levels and changing plant commimities evi- dence alleviation of the mid-Holocene warm period (Mehringer 1986, Davis 1982). Inten- sive human occupation of Hidden (Thomas et al. 1985) and Krammer (Hattori 1982) caves between 3800 and 3600 B.P., with corre- sponding extensive use of marsh plants and animals, indicates that marshes had reap- peared near these sites. Abundant rockfall in pond sediments of this period, especially after ca 3200 B.P., may re- flect accelerated freeze/thaw activity resulting from colder temperatures or greater effective moisture. Because these rocks are found en- closed in fine sediment near the center of the pond, it is possible that they fell onto ice when the pond was frozen and were dropped when the ice melted. Shortly before the fall of the 2845 B.P. vol- canic ash (Tephra III), finely laminated pond deposits are interrupted by a unit of crumb structure with numerous salt crystals and the largest carbonate percentage in the Diamond Pond record. A corresponding sharp increase of greasewood pollen values, decreased aquatic plant macrofossils, but more abundant littoral plant macrofossils support the sugges- tion of a brief but significant drought. Except during this drought, submerged and floating aquatic plants dominate the July 1987 VViciAND: Diamond Pond 455 macrofossil record between 4000 and 2000 B.P. and indicate at least five periods of deeper water (Figs. 23, 24). Following the pre-Tephra IV drought, several aquatic spe- cies either disappeared (Polygonum persi- caria) or became more rare (CcratopJu/Ihim demcrsum). Less-abimdant floating and sub- merged aquatic plants alter 2600 B.P. reflect the transition to a shallower pond due both to sediment accumulation in the maar and drier conditions. After ca 2050 B.P. both the sharp decline of floating and submerged aquatic plant macrofossils with respect to macrofossils of littoral plant and the dramatic tall oi juniper and grass pollen values probably reflect a drop in the water table due to drier conditions. Following 2000 B.P. declining juniper and grass pollen values may reflect their retreat to the higher northern parts of Diamond Craters where water perched in the shallow soils over- lying the basalt flows and a north-focing aspect favored their survival. The sagebrush under- story replaced them as the dominant vegeta- tion. Increased values of juniper and grass pollen indicate expansion of grass and juniper ca 1600 B.P., between ca 1400 B.P. and 700 B. P. , and between ca 450 and 200 B.P. Abun- dant grass characterizes the period between ca 1400 and 700 B. P. , while juniper has only a brief increase about 900 B.P. Harper and Alder (1970, 1972) record a significant moist intei-val between 1500 and 600 B.P. Kelso (1970) inferred, from pollen data, a moist period dominated bv grass beginning about 1500 B.P. Dominance of littoral plant macrofossils in Diamond Pond indicates that water levels re- mained low through the first part of this pe- riod. About 900 to 800 B.P. more abundant submerged and floating a(iuatic plant macro- fossils and greater juniper pollen percentages evidence effectively moister conditions. Greater proportions of clay in the pond sedi- ments also suggest deep water ca 1400 and again ca 1000 B.P. (Figs. 12, 25). After 700 B.P. at least two major droughts, one about 700 and another about 500 B. P. , are indicated by increased values of greasewood. The occurrence of Riippio pollen and seeds and the appearance of the fingernail clam, Musculium securis, indicate that Diamond Pond was more saline and dried out periodi- cally. Analysis of at least one sample from this period showed sediments higher in sand than other sediments from Zone 3 (Figs. 12, 25). In addition, pollen accumulation rates between 800 and 450 B.P. (Fig. 16) are abnormally high. Both factors suggest decreased vegeta- tion cover and increased erosion of the slopes of Malheur Maar. Greater values of grass and juniper pollen about 300 B.P. indicate a return to effectively wetter conditions. This is supported by finer sediment, indicating deeper water (Figs. 12, 25), and by increased submerged and floating aquatic plant macrofossils, especially Cerato- phijUum demersiim (Fig. 19). Aquatic plant abundance is further supported by the pres- ence of large numbers oiFlanorhcUa and Gy- raiilus snails, which favor thick aquatic vege- tation. Becently, more abundant sagebrush pollen and declining juniper and grass values may result from a combination of fire suppres- sion, water diversion, overgrazing, and log- ging, as well as changing climate. Despite the accumulation of at least 15 m of sediment during the past 6000 years, a rising water table has maintained the pond. How- ever, the trend from aquatic to littoral plant dominance reflects the long-term filling of Di- amond Pond that will eventually terminate its existence. Conclusion The detail available in the pollen and macrofossil records from Diamond Pond, es- pecially between 4000 and 2000 B.P., has al- lowed resolution of major climatic episodes lasting only one or two centuries with transi- tions of less than 25 to 40 years (Fig. 24). Relative pollen frequencies from Diamond Pond mirror the response of dominant plant species of the local and regional plant commu- nities to long- and short-term climatic change since the mid-Holocene. Aquatic and littoral plant macrofossils record details of fluctuating water depth of Diamond Pond, as well as the long-term infilling of Diamond Pond. Because aquatic and littoral plants spread and mature rapidly, they are sensitive indicators of chang- ing effective moisture. If the aquatic to littoral plant macrofossil ratio is an accurate indication of fluctuating water table and, by extension, expansion of the Malheur marshes, it seems that they were most extensive between ca 3750 and 3450 B.P. From ca 2800 to 2050, 1000 to 800, and 456 Great Basin Naturalist Vol. 47, No. 3 300 to 150 B.P., more abundant aquatic plant macrofossils indicate recharged local water table and marsh reexpansion. Major littoral plant increases about 2900 and 500 B.P. indi- cate severe drought. Acknowledgments This study is abstracted from a dissertation in the Department of Anthropology at Wash- ington State University. It was initiated as part of the Steens Mountain Prehistory Proj- ect supported in part by National Science Foundation Grants BNS-V7-12556 and BNS- 80-06277 and completed while being partially supported by a Bureau of Land Management grant to study juniper history. Dr. P. J. Mehringer, Jr., recognized the regional paleoenvironmental potentials of the Steens Mountain area over a decade ago and has car- ried on a series of studies that include past vegetation history, volcanic ash chronology, paleomagnetic studies, and regional Holo- cene stratigraphy. Dr. Mehringer was also chairman of my dissertation committee when this study was completed. Chad Bacon, Wilbert Bright, and George Brown of the Bu- reau of Land Management (BLM), Burns of- fice, provided enthusiastic support. BLM botanists Esther Gruber and Joan Price and ecologist Ellen Benedict shared their special knowledge of Diamond Graters. K. L. Pe- tersen, members of the Steens Mountain Pre- history summer field school and of Dr. Mehringer's Washington State University fall 1978 palynology class helped core Diamond Pond. Kate Aasen and Mary Ann Mehringer helped collect plants. Joy Mastroguiseppe, Steve Gill, and Richard Old of the Marion Owenby Herbarium confirmed many plant identifications. Dr. D. W. Taylor identified the mollusks. John Teberg helped with com- puter analysis and plotting, and Karla Kalasz and Derise Wigand helped draft figures. Literature Gited Baker, V R , G. Pickup, and H. A Polach 1985. Radio- carbon dating of flood events, Katlierine Gorge, Northern Territory, Australia. Geologv 13: 344- 347. Bartholomew, M. J. 1982. Pollen and sediment analyses of Clear Lake, Whitman County, Washington; the last 600 years. Unpublished thesis, Washington State University, Pullman. 81 pp. Bentley, E B 1970. The glacial geomorphology of Steens Mountain, Oregon. Unpublished thesis. University of Oregon, Eugene. 98 pp. 1974. The glacial morphology of eastern Oregon uplands. Unpublished dissertation. University of Oregon, Eugene. 2.50 pp. Berggren. G. 1969. Atlas of seeds and small fruits of northwest-European plant species with morpho- logical descriptions. Part 2: Cyperaceae. Berlingska Boktrycherict, Lund. 107 pp. BiRKS, H H , AND R W Mathewes 1978. 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Mountains of the Pacific Northwest, U.S.A.; a study in contrasts. Arctic and Alpine Research 10(2);'465-478. Rich, E E , A M Johnson, and B B Barker, eds 1950. Peter Skene Ogden s Snake Country journals 1824-25 and 1825-26. The Hudson's Bay Record Society, London. 283 pp. Russell. I. C 1903. Notes on the geology of southwestern Idaho and southeastern Oregon. U.S. Geological Survey Bulletin 217. 83 pp. 1905. Preliminary report on the geology and water resource of central Oregon. U.S. Geological Sur- vey Bulletin 252. 138 pp. Smith, W D 1924. The physical and economic geography of Oregon. Commonwealth Review of the Univer- sity of Oregon 7(4); 1.57-194. Soil Sl'RVEY Staff 1951. Soil survey manual. U.S. De- partment of Agriculture, Handbook 18. .503 pp. Sternes.G L 1960. Climates of the states. Oregon. U.S. Department of Commerce, Weather Bureau. Cli- matography of the United States No. 60-.35. 20 pp. Stockmarr, J 1971. Tablets with spores used in absolute pollen analysis. Pollen et Spores 13(4); 615-621. 1973. Determination of spore concentration with an electronic particle counter. Pages 87-89 in Danmarks Geologiske Undersgelse, Arbog 1972. Thomas, D. H.. etal 1985. The archaeology of Hidden Cave. Anthropological Papers of the American Museum of Natural History 61(1). 430 pp. US Department of Commerce. Weather Bureau. 19.53. Climatic siunmary of the United States: Or- egon— supplement for 1931 through 1952. Cli- matography of the United States No. 11-31. 70 pp. 19.54-1984. Climatological data — Oregon: annual summary. No. 13 in each of Vols. 60-90. Urban, K A 1973. Vegetative patterns on Steens Moun- tain, Harney County, Oregon. Blue Mountain Community College, Pendleton, Oregon. Unpub- lished manuscript. .35 pp. Walker, G W 1979. Revisions to the Cenozoic stratigra- phy of Harney Basin, southeastern Oregon. U.S. Geological Survey, Bulletin 1475. 35 pp. Walker. G W., and D A Swanson 1968. Summary re- port on the geology and mineral resources of the Harney Lake and Malheur Lake areas of the Mal- heur National Wildlife Refuge, north-central Har- ney Count)', Oregon, and Poker Jim Ridge and Fort Warner areas of the Hart Mountain National Antelope Refuge, Lake County, Oregon. L^S. Ge- ological Survey, Bulletin 1260-L. 17 pp. Waring, G A. 1909. Geology and water resources of the Harney Basin, Oregon. U.S. Geological Survey, Water-Supply Paper 231. 93 pp. Williams. G,, D E Miller, and D H. Miller, eds. 1971. Peter Skene Ogden's Snake Coimtry jour- nals 1827-28 and 1828-29. The Hudson's Bay Record Society, London. 201 pp. Young, J A, and R. A. Evans 1981. Demography and fire historv of a western juniper stand. Journal of Range Management 34(6); 501-,506. COMPARISON OF HABITAT ATTRIBUTES AT SITES OF STABLE AND DECLINING LONG-BILLED CURLEW POPULATIONS Jean F. Cochran' and Stanley H. Anderson' Abstr.^CT — Long-billed curlew populations were studied in the upper Green River Basin of Wyoming. Sites were selected where curlew populations appear constant in numbers and declining in numbers. Results show that while few habitat diflerences were found between the two areas, disturbances such as grazing and dragging during nesting reduced productivity. Nest failures were also correlated with field fertilization and early season grazing. Within each area curlews nested successfulK on field sites that were elevated and had adecjuate grass cover but not tall grass. Before 1870 long-billed curlews (Nunietiius americanus) nested in relatively high num- bers on prairielike habitats across North America (Audubon 1960, Palmer 1967, Johns- gard 1981). However, extensive hunting vir- tually exterminated the species from the east- ern United States in the last third of the nineteenth century (Bent 1962). Their num- bers continued to decline across the continent during the first 30 years of this century (Bent 1962). In addition to market hunting, many authors have cited plowing and heavy grazing of nesting habitat as causes for this decline (Oberholser 1918, Wolfe 1931, Sugden 1933, Yocum 1956, Johnsgard 1981). During the 1930s, hunting pressure was reduced and efforts were made to reduce grassland grazing pressure on curlew popula- tions (Yocum 1956). Long-billed curlews might have explored newly created "artificial" habitat (annual grasslands and irrigated lands) while native prairies were destroyed during that time period (Pampush 1980, Bicak et al. 1982). Long-billed curlews have four essential nesting habitat requirements in the north- western United States: (1) short grass (less than 30 cm tall), (2) bare ground components, (3) shade, and (4) abundant vertebrate prev (Pampush 1980). Bicak et al. (1982) and Allen (1980) presumed that a preference for large, open vistas and unobstructed forage dictated a need for short vegetation profile. An associa- tion with moist sites or water access has been documented (King 1978), but nests have also been found far from water and in generally arid sites (Bicak et al. 1982). Our objective was to compare habitat char- acteristics and land-use activities between ar- eas with stable and declining numbers of long- billed curlews to determine if habitat factors could be responsible for declines. Study Areas Two study sites were selected in the upper Green River Basin of Wyoming. The Horse Creek site is eight miles west of Daniel near State Highway 354. This two-mile-long area is south of Myrna and Highway 354 and is bounded on the south and west by Horse Creek and Bridger National Forest. Sage- brush {Artemisia tridentata) and aspen (Pop- idus tremuloides) cover the ridges and also encircle the flats except on the eastern outlet. This 3,000-ha area slopes from 2,315-m eleva- tion in the west to 2,270 m in the east. The second site, the New Fork study area, is located between Cora and Pinedale. The 2,000-ha New Fork site is bounded on three sides by sagebrush-covered hills. The eleva- tion drops 8.7 m per km from 2,225 m in the north to 2,190 m in the south. The climate of the upper Green River Basin is classified as continental steppe (Brown 1980). Annual precipitation ranges from 24 to 40 cm per year with 27-62% falling between April and September. Snow falls regularly from September to May, and heavy mountain accumulations provide summer irrigation wa- ter. Summers are short and cool, with the average growing season being 70 to 80 days (U.S. Department of Agriculture 1978). \\'\oming Cooperative Fishen and Wildlife Research I'liit. Box 3166, Uni\ersit> Station, Laramie, Wyoming 82071. 459 460 Great Basin NATUii\LisT Vol. 47, No. 3 The vegetation in the upper Green River is principally sagebrush, with willow {Salix spp.) and sedge (Carex spp.) dominating sloughs in the weathered sites (Vale 1975). These sage- brush flats were converted to flood-irrigated hay meadows from the time of the first home- steads in 1892 to as late as 1960. After brush removal, some meadows were hand-seeded with timothy {Phleiim pratense) and redtop {Agrostis pahistris), while others were left in native graminoids. By the 1940s alsike clover {Thfolium hybridium) and reeds canary grass (Phahirius anindinaceae) had replaced red- top in mi.xed plantings with timothy. Native plants have reinvaded many of the fields. The dominant invaders include wire grass (J uncus balticus) and some rush and mountain timothy (Phlcum alpinum) (Hitch- cock 1921). Many cultivated meadows are the result of conversion, beginning around 1960. These fields are thoroughly plowed, leveled, and then seeded with timothy, alsike clover, milkvetch {Astragalus spp.), meadow foxtail {Alopecurus pratensis), alfalfa {Medicago sa- tiva), and other grasses. Cultivated meadows are fertilized annually with nitrogen or ammo- nium nitrate. In the 1970s some native mead- ows were also fertilized, but this activity has declined markedly since 1978 because of high costs. Approximately 90% of the total hec- tarage at Horse Creek and 83% at New Fork are hay meadows. The percentage of potential long-billed curlew nesting habitat is thus very similar at the two sites. Sheep, cows, and hogs have been raised historically on both study sites, but current livestock are entirely beef cattle. From November to May cattle are confined to feed grounds near four ranches on Horse Creek Flat. After calving in April, herds are gradu- ally shifted through a series of fields begin- ning in mid-May or June. Some fields in this flat are used solely for summer pasture. Many of the summer-pastured cattle come from other wintering groimds near the North Fork study site. The remaining cattle are moved to summer range off the flat. Hay is cut (once annually) from nonsummer-pastured fields starting at the end of July and continuing through August or September. Meadow dragging is a land-use practice which affects ground-nesting birds. This is done in the spring to break up manure piles left by fall- and winter-pastured cattle. Drags can be anything from tree branches or scrap metal tied behind a large log to modern har- rows. Dragging has declined since the mid- 1960s because of fuel and labor costs and a decrease in haying. Both sites are irrigated. At New Fork, wa- ter flow is regulated by a large upstream dam. Spring irrigation water is not released until 1-10 June, leaving fields diy in May. The water is shut off for 7-10 days before haying. Horse Creek has not been dammed. Fields are flooded as soon as the snow melts (usually mid-May), and water continues to saturate the meadows until mid-July in most years. Both areas are underlain by gravel beds up to 9 m deep. These beds fill with water so that the hay crops are irrigated constantly from below, in addition to surface flow. Methods Preliminary observations were made in May-August 1981. During this time we be- came familiar with principal use areas and behavior patterns of curlews. Field sites were then selected. Field data were collected 5 May-20 August 1982. Population indices. — Long-billed cur- lews were counted 5 May-19 July 1981 and 1982 using roadside surveys on prescribed routes in each study area. A modified version of the Breeding Bird Survey (Bobbins et al. 1986) was used to sample the greatest number of birds over a greater distance. Survey results were converted to number of birds seen per kilometer of road surveyed. Twenty-two sur- veys were completed at Horse Creek and 18 at New Fork in 1982. Curlew locations by sex were marked on a 1:24,000 topographic map. Long-billed curlews were sexed bv bill length (Allen 1980). Habitat data. — Native and cultivated fields were sampled at both study areas. Tim- ing and level of grazing pressure based on numbers of cattle were recorded so that com- parisons could be made with curlew use. Each of the 65 hay fields was divided into four 200- m-wide strips, and parallel transects were run down the center of each strip. Preselected random points were located by pacing along transects with only one point per 80-m inter- val. Thus, one random point was selected from each 200 x 80-m block of the field. July 1987 Cochran. Anderson: Long-billed Curlew 461 O 2 CURLEWS 6 se 4 1- a 4^ 4^ c 4^ HC MAY /UNE JULY Fig. L Number of long-billed curlews seen per kilometer surveyed, 5 May-19 JuK 1982; a = date of first hatch at Horse Creek, b = hatch at New Fork, c = last hatch at Horse Creek. Specific habitat variables were measured as follows: visual obstruction or "effective height" (Robel et al. 1970) of hay was esti- mated against a 5-cm-diameter Robel pole marked with alternating black and white 2.5- cm bands. Measurements were taken 1.5 m awa\' from the pole and aligned with the east- west or north-south transect. The approxi- mate eye level for curlews is 30 cm above the ground (Redmond et al. 1981). This was mim- icked by kneeling until the observer's eyes were even with a 30-cm-tall stick. The lowest 2.5-cm band visible on the Robel pole from this vantage point was then recorded as the effective height. From the same position, the within- meadow microtopography was estimated vi- sually by comparing the height of the ground at a random point to the ground 5 m beyond (Skeel 1976). If the sample point was appro.xi- mately 2.5 cm above the surrounding ground, or less, it was classed as level. Drops of 2.5 cm or more below the background usualK' repre- sented the canal or swale. Small, medium, and large hummocks were defined as sample points 2-10, 11-20, and greater than 20 cm above the surrounding ground. Vegetation and bare groimd cover were placed in one of seven cover classes with the aid of a 20 x 50-cm Daubenmier frame (Daubenmier 1959). These classes of cover were grasses, sedges, rushes, forbs, mosses, bare ground, and litter. Soil moisture mea- surements were grouped into three categories for analysis: (1) wet, or standing water, (2) damp, and (3) dr\\ In May the distance to the nearest cow manure pile greater than 2.5 cm in diameter was measured with the Robel pole. Field boundaries and size of vegetation communities were estimated from aerial pho- tos. Land-use data were determined from aerial photos and verified in the field. Inter- views with ranchers indicated dates of drag- ging, fertilizing, and flooding as well as cattle movement. Nesting h.abitat. — Nest searches were concentrated in fields where male curlews had been observed displaying in 1983 (Allen 1980). Defensive and disturbed birds were also used as clues for finding nests. Once nests were located, habitat information was col- lected after chicks had hatched. The following data were collected: horizontal cover by grass or sedge, rushes, forbs, and bare ground around the nest; height of nest; distance from nest to nearest canal, road, building, willow bushes, and manure pile; hay field type; and material used in nest construction. Nesting habitat was then analyzed in four ways. First, 462 Great Basin Naturalist Vol. 47, No. 3 a group of 18 nests was compared randomly to available habitat and hay meadows. Second, comparisons were made between individual nests and habitat data from the fields in which they were located. Third, comparisons were made between successful and failed nest sites. Comparisons were also made between nest fields and non-nest or avoided fields. Starting in June, nests were monitored through hatching. Every three to seven days the incubating bird was flushed so that eggs could be checked for signs of hatching. Other- wise, nests were observed from a distance of 10 to 100 m to confirm the presence of an incubating curlew. Disturl:)ance to nesting birds was minimized by walking directly to the nest from the same direction and staying within the nest field or site of the curlew as briefly as possible. A few paradichloroben- zene crystals were scattered after the ob- server's trail to discourage scent-tracking predators (Redmond 1986). Flushing dis- tance, distraction-display response to other birds, and time of day were noted on each visit. Data analysis. — Data were analyzed with SPSS Batch System: Statistical Packages for the Social Sciences (Nie et al. 1975). The pro- grams used were BREAKDOWN, FRE- QUENCY, T-TEST, ONE-WAY (analysis of variance or AOV; stepwise and multiple) RE- GRESSION. All analyses of variance were one-way, and all t-tests were unpaired or un- pooled. Differences between means are con- sidered significant if probabilities were less than .05. Results Population indices.- — Roadside counts of curlews showed significantly more birds per kilometer of road at Horse Creek, where curlew numbers increased until 10 June and then declined to 18 July. New Fork counts showed more variation but were consistently lower than Horse Creek. The highest count of birds was 4.06/km at Horse Creek and 1.45/ km at New Fork (Fig. 1). Habitat COMPARISONS. — No vegetation dif- ferences were apparent from May surveys be- tween cultivated and native field types. Spring grazing had repressed vegetation height to a mean of 2.38 cm in June. Ungrazed native fields averaged 4.78-5.63 cm, and cul- tivated hays had grown from 7.88 to 9.88 cm. Further, spring-pastured meadows were sig- nificantly shorter than both hayed only and fall-pastured meadows (all probabilities are significant if less than .05). When all land-use types were pooled, no significant diflPerences in vegetation height were detected between New Fork and Horse Creek in either May or June. When various types were considered separately, minor dif- ferences arose. Native hayed, pastured fields were shorter at Horse Creek than at New Fork in May (1.25 vs. 1.48 cm). Again in June, a difference between native fields at the two study sites was found. Only cultivated hay samples were consistently taller in June at Horse Creek than New Fork. Thus, vegeta- tion height or visual obstruction differed be- tween land-use types in the growing season (June). Coverage by grasses, sedges, rushes, and bare ground differed between cultivated and native fields but not between study sites. Overall, ground cover in native fields aver- aged 24.4% grasses, 23.6% sedges, 22.7% bare ground, 9.9% rushes, 7.8% forbs, and 0.8% mosses (10.9% was unaccounted for be- cause cover classes included a 0% but not 100%). In cultivated fields, ground coverage averaged 68.7% grasses, 10.1% forbs, 9.3% bare ground, 1.9% sedges, 0.8% rushes, and 0.4% mosses. Thus, native fields were cov- ered by approximately equal (juarters of grasses, sedges, bare ground, and all other plants, while cultivated fields were at least three-quarters grasses and about one-tenth each forbs and bare ground. Despite the planting of clover in cultivated fields, these meadows did not average significantly more forb coverage than did native fields. Coverage by grasses was significantly greater in culti- vated hay fields but did not differ between study sites. The average ground height was not signifi- cantly different in cultivated, native Horse Creek or New Fork fields. However, average height may not convey the relative "bumpiness" of fields. In casual observation, some native fields contained numerous hum- mocks, but all cultivated fields had been lev- eled. All meadows were significantly wetter in June than May due to irrigation, but Horse Creek had even more wet ground than New July 1987 Cochran, Anderson: Long-billed Curlew 463 Fork when both were irrigated. Horse Creek was also significantly wetter than New Fork in May when these sites were compared. Pooled samples (May plus June) showed that Horse Creek meadows were wetter than New Fork meadows. Nesting success. — At Horse Creek, cur- lews hatched from 15 June to 12 July 1982. The one hatch seen at New Fork occurred on 24 June. The second New Fork clutch had hatched by 20 June when we visited the nest, and the third brood seen there was probably one to two weeks old on 24 June. Thus, mean hatch date on Horse Creek was 1 July, and New Fork mean hatch was 24 June. We observed 21 long-billed curlew nests in 1982. Of the 21 nests, 3 were in cultivated hay, 1 in an unmowed slough, and 1 in an overgrazed, dry pasture. The remaining 16 curlew pairs nested in subirrigated, native hay meadows that were mowed annually. Three of these were in fields that were never pastured. Using the Mayfield (1961, 1975) method, which compensates for unknown nest- initiation dates of failed nests, we calculated an overall nest-survival rate of 33.6%. Forty- four percent of the young survived from all Horse Creek nests, while 28.3% of non-Horse Creek nests lived. Clutch size was 3.83 with an incubation period of 28 days. Redmond and Jenni (1986) found similar re- sults in Idaho with most females laying four eggs and incubating 28 days. Nesting habitat. — Grass cover immedi- ately around 18 nests was almost double the grass in fields generally. Nests were built in sites with less bare ground than the fields overall. Where the ground had not been lev- eled (native fields), nests were found on sites significantly higher than mean level ground. Average height at nest sites was 6. 1 cm above the ground in a radius of 1-5 m around the nest. These heights were classed as either small hummocks or level ground. Six of the 15 nests were on hummocks (at least 2.5 cm above surrounding ground). Two of these were higher than 20 cm, while only 2 out of 320 randomly sample points were that high. Chicks hatched successfully from 5 of the 6 hummock nests (the sixth was destroyed by dragging), but 6 of the 9 level nests tailed. No nests were on depressed ground (less than 2.5 cm below the surrounding ground). Nests were found in fields that had signifi- cantly less bare ground than did the randomly sampled fields. Nests built where cattle had pastured were directly against a manure pile. Clearly, these nests were closer to conspicu- ous objects than could be expected from ran- dom placement. When hatching success for 21 nests was regressed on conditions surrounding the nests, two land uses were found that pre- dicted nest failure: grazing during incubation, and field fertilization. Nest field dragging, nest flooding, and nest height did not corre- late with nest failure. The last measure of nest habitat selection was the comparison of fields used for nesting and those not used. Three habitat traits were significantly different between these fields: percent cover by grasses, percent cover by forbs, and soil moisture. Nest fields had less grass cover (19.9%) than avoided fields (31.9%). But forbs were greater in nest fields (15.5%) than in the others (3.5%). Rush and sedge cover were not different between field types (10-24% rushes). Nesting curlews avoided nesting in fields where only 3% of the ground surface was dry but nested in fields that were 45% dry. No difference was observed in mean visual ob- struction height of vegetation in these fields. These results provided some insight into rea- sons for differences in curlew populations at the two study sites. Short vegetation was not common at New Fork. Human activities asso- ciated with ranging (fertilizing and dragging) were more common at New Fork than at Horse Creek. Discussion Vertical vegetation cover is a measure of visual and foraging obstruction to ground birds such as long-billed curlews. These birds utilize areas with low vegetation profile (Bent 1962, Bicak et al. 1982, Redmond 1986). The decline of long-billed curlews parallels an in- crease in meadow conversion to taller culti- vated fields. Curlews, however, do use culti- vated fields, particularly if grazing pressure keeps vegetation low. At the Horse Creek study site, conversion to cultivated hay matched in timing and extent an increase in summer pasturing, which provides extremely short vegetation profiles. 464 Great Basin Natur.\list Vol. 47, No. 3 Nest sites were analyzed to determine if curlew land-use practices, which were not ap- parent from the general description of hay meadows, impacted birds. Four land uses re- duced the availability of preferred nest sites: seeding in cultivated fields, land leveling in cultivated fields, irrigation, and dragging. Of these, only irrigation and dragging were dif- ferent between the two sites. Based on the mean placement of nests in 61% grass and 7% bare ground, cultivated hays would seem to provide good cover for curlew nests. Yet, curlews selected microsites of high-grass den- sity rather than whole fields dense in grass. Evidence for this was threefold: (1) 50% of nests were in higher grass cover than occurred overall in their respective nest fields; (2) nest fields had lower grass cover than avoided fields (at New Fork); and (3) curlews avoided nesting in cultivated fields. Thus, while culti- vated hays seemed to have increased the availability of preferred ground cover, ade- quate grass cover was provided b\' native fields. Nesting on hummocks could have provided two advantages: better visibility (of preda- tors), and dry nests. Nest flooding must be detrimental because curlews nested in both drier-than-average microsites and drier-than- average fields. Jenni et al. (1982) also found that curlews nested on the most xeric slopes in their study area. Some observers have claimed that cattle- grazing is beneficial to long-billed curlews be- cause it maintains low vegetation profiles (Sugden 1933, Timken 1969, Pampush 1980, Bicak et al. 1982). Year-long grazing was not helpful to curlews in Idaho (Redmond and Jenni 1982). In Nebraska, curlews were shown to use summer-grazed fields and avoid winter-grazed pastures (Bicak 1977). Haying is also a mechanism used to obtain shorter vegetation; however, timing is an im- portant factor. When cultivated fields are fer- tilized and hayed later in the season, harm to nests may not occur, but the birds probably avoid the fields because of taller grass during the time of nest construction (Bicak 1977). Many authors have mentioned that curlews use agricultural lands, but only Bicak (1977) studied them on hay meadows. Uncultivated rangelands and pastures support most of the continental long-billed curlew breeding pop- ulation (Johnsgard 1981, Pampush 1980). Curlews rarely nest in alfalfa, crested wheat- grass {A^ropyron cristatum), or fallow fields (Renaud 1980, Pampush 1980, Jenni et al. 1982). Intensive cultivation and mechanical irrigation are detrimental to curlews or even preclude curlew use (Wolfe 1931, Yocum 1956, Bent 1962, Renaud 1980, Pampush 1980, Jenni et al. 1982). Prior studies have rarely investigated water in relation to curlews. McCallum et al. (1977) reported that 41% of curlews observed on Colorado prairies were within 100 m of water. They suggested that curlews select nest sites near water, even though these sites are dry in some years (curlews are very nest-site tena- cious; Redmond and Jenni 1982). Limited wa- ter sources could then explain the patchy dis- tribution of curlews where short-grass habitat is not limiting (McCallum et al. 1977). Wet meadows were the limiting habitat for curlews in Nebraska's Sandhills (Bicak 1977). These subirrigated meadows supply the abun- dant invertebrate prey required by curlew broods. As a result, wet-meadow, brood- rearing territories are more intensively de- fended than hillside nest territories. Other authors have suggested that moisture is re- quired by curlews or that they readily exploit abundant foods on irrigated lands (Bent 1962, Sugden 1933, Forsythe 1970, Renaud 1980, Pampush 1980, Bicak et al. 1982). The dominant characteristics of the irri- gated lands we studied, aside from graminoid vegetation, were ubiquitous water and large insect populations (predominantly mosqui- toes). These insects began emerging on 13 June 1982 at Horse Creek and were extremely numerous by 17 June. The irrigated hay meadows used by curlews in this study correspond to Pampush's (1980) mixed-grass meadow habitat type. He found curlews on this habitat in the Upper Snake River Basin and other parts of eastern Idaho, as well as Malheur National Wildlife Refuge in Oregon. Cameron (1907) described similar curlew habitat in south central Montana where "tributary creeks . . . rise into pine hills which enclose wide parks." McCallum et al. (1977) documented curlew nesting in the "large, high altitude (over 7,500 ft [2,280 m]) unforested valley" of North Park, Colorado. Subirrigated meadows in North Park are simi- lar to the Upper Green River Basin. Bicak (1977) and Forsythe (1972) also documented July 1987 COCHKAN. ANDERSON: LONC-BILLKD CURLP:\V 465 curlew use of wet pastures and ha>^ meadows in Nebraska and Utah. Dragging hay meadows to break up cow manure appeared to be detrimental, as this process in Wyoming occurred at about the time oi nesting. Dragging has declined drasti- cally since 1960 at Horse Creek. Prior to 1960, 75 to 85% of all meadows were dragged. Then, as ranch sizes increased (by conglomeration) and hired help decreased. Horse Creek ranchers stopped dragging their fields. Drag- ging declined to 44% in the 1960s and to only 8% (or foin- fields) by 1975. Fuel prices, shifts to cultivated hay (not grazed enough to war- rant dragging), and summer pasturing have virtually eliminated this 80-year-old practice from Horse Creek. Dragging is essentially un- changed at New Fork (still 85%). Since few fields are dragged at Horse Creek, manure piles are abundant. Curlews place their nests near manure piles, if they are available; and successful nests are slightly closer than failed nests to manure (though not significantly closer). This tendency to nest near manure has been documented (Silloway 1900, Bent 1962, Wolfe 1931, Sugden 1933, Allen 1980). Nesting near or on conspicuous objects like manure piles camouflages the curlews from aerial predators. In summary, cultivated fields provided the preferred grass and bare ground but not hinii- mock nest sites. (High vertical cover and fer- tilization could also limit cultivated-hay nest- ing, even though grazing and dragging disturbances were absent.) Conscribed irriga- tion at New Fork provided a greater area of dr\' soil for nests. Conversely, Horse Creek had more fields with conspicuous manure piles for nest sites and fewer dragging distur- bances. As a result of availability of habitat — mixed fields with adequate, but not tall, grass cover and fields with elevated points — curlews seemed to be more successful in nest- ing and could thereby maintain their popula- tions. Disturbances such as dragging during nesting could destroy nests. Grazing during incubation and field fertilization were corre- lated with nest failures and a declining popu- lation of curlews. Acknowledgments We appreciate William Eddleman the helpful comments of Debborah Finch, and Dennis Knight. Bob Oakleaf provided a great deal of valuable information. We especially appreciate the assistance and openness of the ranchers of Merna and New Fork, Wyoming. Literature Cited Allen, J N 1980. The ecology and behavior of the long- billed curlew in southea.stern Washington. Wildl. Mono. 7.3. Aldlbon, M R 1960 (1897). Audubon and his journals. Vol, II, Dover Publ,, Inc, New York, Bent. A. C. 1962 (1929), Life histories of North American shorebirds. Part II, Dover Publ,, Inc., New York. Bic.AK, T K. 1977, Some eco-ethological aspects of a breeding population of k)ng-billed curlews (Nmne- niiis cimcricaiuis) in Nebraska, Unpublished the- sis. University of Nebraska, Omaha, Bic.\K. T. K , R. L Red.mond. .\nd D A Jennl 1982. Ef- fects of grazing on long-billed curlew (Ntimeniiis ainericanu.s) breeding behavior and ecology in southwestern Idaho, Pages 74-85 in J, M, Peak and P, D, Dalke, eds,. Wildlife-livestock relation- ships symposium: proceedings 10. University of Idaho Poorest, Wildl, and Range E.xpt, Sta., Moscow, Idaho, Brown. R H 1980. Wyoming: a geography. Westview Press, Boulder, Colorado, Dauben.mire. R. 19.59. A canopy-coverage method of veg- etational analvsis. Northwest Science .33(1): 43-64. FoRS\THE. D M 1970. Vocalizations of the long-billed curlew. Condor 72(2): 213-224. 1972. Obser\ations on the nesting biology of the long-billed curlew. Great Basin Nat. .32(2): 88-90. IlncHCOCK. A S 1921, A manual of farm grasses, Publ. by the author, Washington, D. C. Jennl D A . R. L. Redmond. andT K. Bicak 1982. Be- havioral ecology and habitat relationships of long- billed curlews in western Idaho. Unpublished re- port, U.S. Dept. Interior, Bur. Land Manage., Boise, Idaho. JoHNSGARD, P A 1981. The plovers, sandpipers, and snipes of the world. University of Nebraska Press, Lincoln. Mavfield. H F 1961. Nesting success calculated from exposure. Wilson Bull. 7,3(3): 255-261. 1975. Suggestions for calculating nest success. Wilson Bull. 87(4): 4.56-466. McCallum, D a , W D Graul. and R Z,\ccac;ninl 1977. The breeding status of the long-billed curlew in Colorado. Auk 94(3): .599-601. NiE, N H . C H Hull, J G Jenkins, K Steinbrenner. AND D H. Bent. 1975. SPSS; statistical packages for the social sciences. 2d ed. McGraw-Hill, New York. Oberholser, H C I9I8. Notes on the subspecies of Numenitis americamis Bechstein. .\uk 35(2): 188-195. Pampush. G J 1980. Status report on the long-billed curlew in the Columbia and northern great basins. LInpublished report, U.S. Dept, Interior, Fish and Wildl, Serv,, Portland, Oregon, 466 Great Basin Naturalist Vol. 47, No. 3 Redmond, R L 1986. Egg size and laying date of long- billed curlews (Numenius amehcaniis): implica- tions for female reproductive tactics. Oikos 46:330-338. Redmond, R L., and D A Jenni 1982. Natal philopaty and breeding area fidelity of long-billed curlews (Ntimenius americanus). patterns and evolution- ary consequences. Behav. Ecol. Sociobiol. 10; 177-228. 1986. Population ecology of the long-billed curlew (Numenitis aincricanus) in western Idaho. Auk 103: 755-767. Redmond, R L , T K Bicak, and D A Jenm 1981. An evaluation of breeding season census techniques for long-billed curlews (Nuiuenius americanus). Pages 197-201 in]. C. Ralph and J. M. Scott, eds.. Estimating numbers of terrestrial birds. Studies in Avian Biol. 6. Allen Press, Lawrence, Kansas. Renaud, VV E 1980. The long-billed curlew in Saskatchewan: status and distribution. Blue Jav 38(4): 221-237. RoBBiNS.C S , D Bystrak, andP. H Geissler 1986. The breeding bird survey: its first fifteen vears, 1965-1979. U.S. Dept. Interior, Fish and Wildlife Service, Resource Publication 137. Washington, D. C. RoBEi.. R J , J N Bbk;(;s A D Dayton, and L C Hul- BERT 1970. Relationships between visual obstruc- tion measurements and weight of grassland vege- tation. J. Forestry 39: 295-297. SiLi.owAY, P M 1900. Notes on the long-billed curlew. Condor 2: 79-82. Skeel, M a 1976. Nesting strategies and other aspects of the breeding biology of the Whimbrel at Churchill, Manitoba. Lhipublished thesis. Uni- versity of Toronto, Toronto, Ontario, Canada. Sugden, J. W 1933. Range restriction of the long-billed curlew. Condor 35(1): 3-9. TiMKEN, R. L 1969. Notes on the long-billed curlew. Auk 86(4): 750-751. US Department of Agriculture 1978. Green River Basin, Wyoming, cooperative river basin study: main report. U.S. Forest Serv. and Soil Conserv. Serv., Casper, Wyoming. Vale, T. R 1975. Prescttlement vegetation in the sage- brush-grass area of the Intermountain West. J. Range Manage. 28(1): 32-36. Wolfe, L. R 1931. The breeding Limnicolae of Utah. Condor 33(2): 49-59. YocL'M.C F 1956. Re-establishment of breeding popula- tions of long-billed curlews in Washington. Wilson Bull. 68(3): 228-231. ESTIMATES OF SITE POTENTIAL FOR PONDEROSA PINE BASED ON SITE INDEX FOR SEVERAL SOUTHWESTERN HABITAT TYPES Kohfit L. Mathiasen', Elizabeth A. Blake', and Carleton B. Edminster" Abstr.\(:t — Estimates of site potential ior ponderosa pine based on measured site indexes in 416 stands are eompared between seven habitat types and one community type. No significant differences in mean site index are found between the habitat types studied. The habitat types are classified into high or moderate site potential classes based on mean site indexes. Ponderosa pine {Pinus ponderosa Laws.) is the most important commercial timber spe- cies in the southwestern United States. Pon- derosa pine forests occupy the largest area of commercial forest land in Arizona and New Mexico (Choate 1965, Spencer 1966). Pon- derosa pine forests reach their maximum de- velopment in the Southwest at elevations be- tween 7,000 and 7,800 feet, but also occur at higher and lower elevations (ranging from 6,000 to 8,500 feet) (Schubert 1974). At the lower elevations ponderosa pine forests inter- grade into pinyon-juniper forests. At higher elevations, ponderosa pine grades into the Douglas-fir and white fir forest types (Shep- pard et al. 1983). Because of their commercial value, pon- derosa pine forests are intensively managed for timber production in the Southwest. Many management decisions are based on site class or quality classifications. Classification of land into site quality or production potential classes provides a useful means for identifying areas where the potential for improved pro- duction is greatest (Schubert 1974). In addi- tion, recently developed growth and yield simulation models for southwestern pon- derosa pine rely on site quality determination as an important variable for predicting yields over time (Edminster 1978, Larson and Minor 1983). Site index is currently the most widely used method of evaluating site quality or potential productivity of forest lands in the United States (Jones 1969, Husch et al. 1972, Daubenmire 1976). Site index is based on the average heights of dominant and codominant trees at a specified index age (usually 50 or 100 years). Because stands of the index age are seldom encountered, site index curves are constructed to allow for estimation of site in- dex for stands older or younger than the index age by interpolation between curves. Site in- dex curves describe the height growth of hy- pothetical trees of specified site indexes. Because Meyer's (1961) site curves for pon- derosa pine tend to underestimate site quality for the species in the Southwest (Schubert 1974), Minor's (1964) ponderosa pine site curves for Arizona and New Mexico are more frequently used for site potential estimates. Minor's curves are developed for dominant trees with breast-height ages of 20 to 140 years and site classes from 40 to 100 feet. Site index classes over 100 can be calculated using an equation presented by Minor (1964). The use of habitat types (Daubenmire 1952) to classify forest vegetation is gaining accep- tance by land managers and researchers in the western United States (Layser 1974, Pfister 1976, Pfister and Arno 1980). One of the pri- mary uses of habitat types is in timber man- agement where they are used to compare re- generation success, succession patterns, cutting methods, and timber productivity and to develop guidelines for collecting seed and plant nursery stock (Pfister and Arno 1980). The use of habitat types to predict forest site productivity potential or site quality is proposed by several investigators. Differ- ences in the rate of height growth by habitat type are demonstrated for several tree species Northern Arizona UniversiU', School of Forestr>. Flagstaff, .Arizona 86011. USDA Forest Ser\'ice, Rocky Mountain Forest and Range E.xperiment Station, Fort Collins, Colorado 80526. 467 468 Great Basin Naturalist Vol. 47, No. 3 (Daubenmire 1961, Deitschman and Greene 1965, Stanek 1966, Stage 1975, HoflFman 1976, Monserud 1984). Significant differences between site indexes are also shown for habi- tat types (Stanek 1966, Stage 1975, Hoffman 1976, Mathiasen et al. 1986). Pfister et al. (1971, 1977) and Steele et al. (1981) use site index curves and normal yield tables to esti- mate yield capability for habitat types in Mon- tana and Idaho. Habitat type classifications are recognized for southwestern ponderosa pine forests and for forest types where ponderosa pine is often associated with Douglas-fir {Pseudotsuga menziesii [Mirb.] Franco) and white fir (Abies concolor [Gord. & Glend. ] Lindl.) (Alexander 1985). However, little information is available for ponderosa pine site quality for recognized southwestern habitat types (Moir and Ludwig 1979, Hanks et al. 1983, Fitzhugh et al. 1984, DeVelice et al. 1986). Schubert (1974) pro- vides a summary of the silviculture of south- western ponderosa pine and emphasizes the need for tying growth and yield simulation models to habitat types. Because site quality is a key variable in ponderosa pine growth and yield models, site quality estimates for differ- ent habitat types are needed for the South- west. This study provides additional quantita- tive data on site quality based on site index measurements for ponderosa pine for several southwestern forest habitat types and one community type. Methods Total height and age at breast height were measured for two to six vigorously growing dominant or codominant ponderosa pines in 416 stands representing the southwestern ponderosa pine (314), white fir (92), and Dou- glas-fir (10) forest types. Trees with visible signs of abiotic, insect, or disease damage were not selected as site trees. The following information was recorded for each stand: na- tional forest, location (township, range, and section), elevation (nearest 100 feet), aspect (four cardinal directions), slope (nearest 5%), slope position (flat, bottom, ridge, slope), and habitat type (HT) (Moir and Ludwig 1979; Hanks et al. 1983; Alexander et al., Lincoln National Forest, 1984; Alexander et al., Dou- glas-fir habitat, 1984; Alexander et al., Gibola National Forest, 1984; Fitzhugh et al. 1984; Table 1. Southwestern ponderosa pine, Douglas-fir, and white fir habitat and community types sampled. Refer to Literature Cited for full reference to footnote citations. Ponderosa Pine Habitat Types PIPO/MUVLPniw.s ponderosa/Muhlenher^ia virescens^ PIPO/FEAR:P(ni/.s- ponderosalFestuca arizonica^*^ ?l?0/BOGl{:Pinusponderosa/Boutelouaf!,racilis^^^ PIPO/QUG A.Pinus ponderosa/Quercus ^ambelii '"'^^ Ponderosa Pine Community Types PIPO/POLO:Ptnus ponderosa/Poa longiligida^ Douglas-fir Habitat Types PSME/FEAR;P.s•e»f/o^s■(/ga menziesii/ Festuca arizonica^ White Fir Habitat Types ABCO/QUGA:A/;!t'.s' concolor/Quercus gambelii^^'* (Abies concolor-Psetidotsttga menziesii/Qiiercus gambelii'') ABCO/BEKE.Abies concolor/ Berberis repens ' (Abies concolor-Pseiidotsuga irienziesii/ [sparse]^) Alexander, Roiico, Fitzhugh, and Ludwig 1984. "Alexander, Ronco, White, and Ludwig 1984. 'De\ehce et al 1986 ^p-itzhugh et al. 1984. ■^Hanks et al. 1983. •^Moir and Ludwig 1979. "Vounghlood and Mank 198.5. Youngblood and Mauk 1985; DeVelice 1986). A total of seven habitat types and one commu- nity type (CT) were sampled (Table 1). Stands sampled were located in the Apache (34 stands), Goconino (77 stands), and Kaibab (54 stands) national forests, Arizona; the Carson (36 stands), Cibola (15 stands), Gila (8 stands), Lincoln (11 stands), and Sante Fe (68 stands) national forests, New Mexico; and the San Juan National Forest, Colorado (113 stands). Site indexes were determined from average total height and breast height age data for each stand using the ponderosa pine site index curves developed by Minor (1964). Site in- dexes for stands with site indexes greater than 100 feet were calculated using the site index equation presented by Minor (1964). Mean site index and standard deviation were calcu- lated for each habitat type and community type sampled. A one-way analysis of variance, with p =^ .05, was used to compare mean site indexes among habitat types. The Student- Newman-Keuls test was applied to the analy- sis to determine where significant differences occurred. Results Mean site indexes ranged from a low of 74.3 for the PIPO/BOGR HT to a high of 87.0 for July 1987 Mathiasen etal.: Ponderosa Pine Site Potential 469 Table 2. Mean ponderosa pine site indexes, standard deviations, 9.5% confidence limits, and site potential classes by habitat and community type. Number 95% Site Habitat of confidence potential type stands Mean' limits class PSME/FEAR 10 87.0 ± 12..5 78.1 -95.9 High pipo/fear 112 83.6 ± 11.2 81.5 - 85.7 High abco/quga 72 83..5 ± 11.1 80.9-86.1 High pipo/quga 135 82.3 ± 1.5.1 79.8 - 84.9 High PIPO/MUVI 12 81.1 ± 8.6 75.6 - 86.6 High ABCO/BERE 20 79.3 ± 12.7 73.3 - 85.3 High PIPO/POLO 16 79.7 ± 8.5 75.2 - 84.2 High (Comni. Type) PIPO/BOGR 39 74.3 ± 13.4 69.9 - 78.6 Moderate TOTAL 416 'No sjgnifRant dilTeri-nces were detected between mean site indexes using the Student-Newman-Kuels test, p - .05. the PSME/FEAR HT (Table 2). Standard de- viations ranged from 8.5 for the PIPO/POLO CT to 15.1 for the PIPO/QUGA HT. None of the mean site indexes was found to be signifi- cantly different at the p ~ .05 level. Pon- derosa pine forests in Arizona and New Mex- ico are grouped into three site classes for management reasons by the U.S. Forest Ser- vice (Southwest Region). The groupings are based on potential cubic feet/acre/year pro- ductivity estimates and use Minor s (1964) site index curves: Site Class 1 represents site in- dexes above 75, Site Class 2 represents site indexes from 55 to 74, and Site Class 3 repre- sents site indexes less than 55. Although the mean site indexes for the habitat type sampled in this study were not significantly different, site potential classes for ponderosa pine were assigned for the habitat types based on mean site indexes and the above site class system used by the Forest Service. Our high and moderate site potential classes correspond to Site Class 1 and Site Class 2, respectivelv (Table 2). Discussion Site index is currently the most widely ac- cepted method of evaluating site quality in the United States. Several investigators report significant differences in site index between habitat types for several tree species (Stanek 1966, Roe 1967, Hoffman 1976, Mathiasen et al. 1986). However, our results indicate no significant differences between mean site in- dexes for ponderosa pine between the seven habitat types and one community type sam- pled in this study. Daubenmire (1961) rejects the use of ponderosa pine site index curves for predicting potential productivity of habitat types because he found large variations be- tween the site indexes of contiguous young and old stands of ponderosa pine in burned areas representing homogeneous habitats. Daubenmire reports that ponderosa pine grows faster than site index curves predict. Other investigators report similar findings for other tree species (Ilvessalo 1927, 1937, Carmean 1956). In addition, stand density, soil variation, and early suppression of trees can affect the validity of site quality determi- nations based on site index curves (Jones 1969). Therefore, our estimates of site quality for ponderosa pine presented here and for Douglas-fir (Mathiasen et al. 1986) based on site index may be underestimating actual site potential for the habitat types we have sam- pled thus far. However, site index is consid- ered to be the best practical indicator of rela- tive site qualitv at this time (Hodgkins 1956, Vincent 1961, Jones 1969, Husch etal. 1972). Based on the U.S. Forest Service site class system and our mean site indexes for pon- derosa pine, all but one of the habitat types sampled in this study are classified as high site potential (Class 1) habitat types. Although there was a large degree of variation in site index for each of the habitat types sampled (standard deviations averaged 11.6), site po- tential ranges are represented best by their 95% confidence limits; most of the habitat types' 95% confidence limits are within the high site potential class (Table 2). In their descriptions of habitat type classifi- cations, several investigators report site qual- ity estimates for ponderosa pine in southwest- 470 Great Basin Naturalist Vol. 47, No. 3 em forest habitat types (Moir and Ludwig 1979, Hanks etal. 19'83, Alexander etal. 1984, Fitzhugh et al. 1984, Youngblood and Mauk 1985, DeVelice et al. 1986). Onr estimates of site quality for ponderosa pine by habitat type support the estimates made bv Fitzhugh et al. (1984) and Hanks et al. (1983) for the PIPO/ FEAR HT (moderate to high). However, De- Velice et al. (1986) report low site potential for ponderosa pine in the PIPO/FEAR HT in northern New Mexico and southern Colo- rado. Fitzhugh et al. (1984) report high poten- tial for ponderosa pine in the PIPO/MUVI HT. Our results essentially agree with their estimate. Moir and Ludwig (1979) report stands with what they consider low site poten- tial for ponderosa pine (site index of about 65) in the ABCO/QUGA HT. DeVelice et al. (1986) and Hanks et al. (1983) report low or poor site potential for the ABCO/QUGA HT. However, our site index data for this habitat type indicate high site potential for ponderosa pine. Our findings also indicate higher site potential for ponderosa pine in the PS ME/ FEAR HT (high site potential) than reported by DeVelice et al. (1986) (low site potential). Hanks et al. (1983) report that the PIPO/ BOGR HT probably represents the lowest site potential of any ponderosa pine habitat type in the Southwest. However, our results indicate that site potential is moderate for this habitat type. Site potential estimates for pon- derosa pine have not been reported for one of the habitat types and the community type sampled in this studv. Based on our site index data, site qualitv for the ABCO/BERE HTand the PIPO/POLO CT is high. Hanks et al. (1983) state that the PIPO/POLO CT is "suitable for timber production, and we agree with their evaluation. The reasons for differences in ponderosa pine site quality estimates for southwestern forest habitat types by various investigators are primarily the result of geographic varia- tion in site indexes (Monserud 1985) or differ- ences in criteria for interpreting site index data in relation to site qualitv. Hanks et al. (1983) and Fitzhugh et al. (1984) do not ex- plain the basis for their estimates of ponderosa pine site quality, but their estimates do not appear to be based on quantitative site index data collected during their field work. De- Velice et al. (1986) base their estimates on site index data and rate ponderosa pine site qual- ity using the standard U.S. Forest Service Southwest Region site class groupings de- scribed earlier. We also base our site potential estimates for ponderosa pine on the Forest Service site class groupings and suggest that future habitat type classifications adopt this system to have consistent criteria for estimat- ing site quality for habitat types in the South- west. Even though we used the same site class system, our estimates of ponderosa pine site potential vary a great deal from those of De- Velice et al. (1986). The most probable expla- nation for the differences between our site potential estimates and those of DeVelice et al. is that ponderosa pine and Douglas-fir tend to demonstrate much lower site indexes in the Sangre de Cristo Mountains of northern New Mexico and southern Colorado (Moir and Ludwig 1979), where DeVelice et al. (1986) collected much of their site index data. There- fore, site quality estimates for southwestern habitat types based on habitat type classifica- tion studies from specific geographic areas or national forests may not adequately represent the range in site potential classes encountered in the Southwest. Several authors discuss the problems with using site index data to estimate site quality (Hodgkin 1956, Vincent 1961, Daubenmire 1961, 1976, Jones 1969). Although site index data are generally regarded as a somewhat rough estimate for productivity potential of forest land, they are still accepted as the most practical and direct method for evaluating rel- ative productivity (Vincent 1961, Jones 1969, Husch et al. 1972, Daubenmire 1976). Site quality estimates for forest habitat types based on site index data are still applicable to cur- rent forest management procedures, but be- cause large variations occur in site indexes within habitat types, the use of habitat types for predicting timber productivity potential is imprecise. However, because timber produc- tivity is primarily estimated from site index information, site class estimates based on site index data should be determined for addi- tional southwestern habitat types and other commercially important tree species. In addi- tion, our site quality estimates for ponderosa pine and for Douglas-fir (Mathiasen et al. 1986) for several southwestern forest habitat types should be supported or modified if nec- essary with additional site index data collected from stands classified by habitat type. July 1987 Mathiasen etal.; Ponderosa Pine Site Potential 471 The development of separate site index curves for different habitat types may improve the accuracy of site index as an estimate of site quality (Monserud 1984). Furthermore, the development and subsequent validation of growth and yield simulation models using growth coefficients based on habitat types (Stage 1973, 1975) may improve productivity estimates for habitat types. Literature Cited Alexander. B G.Jr., E L Fitzhugh, F Rgnco.Jr , and J. A. LUDWIG. 1984. A classification of forest habitat of the Cibola National Forest, New Mexico. USDA Forest Service. Mimeo of manuscript in preparation. 120 pp. Ale.xander. B G , Jr , F Rgnco.Jr , E L Fitzhugh, ,\nd J A Ludw'IG 19S4. A classification of forest habitat types on the Lincoln National Forest, New Mex- ico. USDA Forest Service, Gen. Tech. Rept. RM- 104. 29 pp. Alexander, B G . Jr.. F Rgnco.Jr A S VVhite..\ndJ A Ludw'IG. 1984. Douglas-fir habitat types of north- ern Arizona. USDA Forest Service, Gen. Tech. Rept. RM-108. 13 pp. Alexander. R R 1985. Major habitat t\ pes, community types, and plant communities in the Rocky Moun- tains. USDA Forest Service, Gen. Tech. Rept. RM-123. 105 pp. Carmean, W. H 1956. Suggested modifications of the standard Douglas-fir site curves for certain soils in southwestern Washington. For. Sci. 2: 242-250. Chg.ate. G a 1966. New Mexico's forest resource. USDA Forest Service, Res. Bull. INT-5. 60 pp. Daubenmire, R 1952. Forest vegetation of northern Idaho and adjacent Washington, and its bearing on the concepts of vegetation classification. Eeol. Monogr. 22; 301-330. 1961. Vegetative indicators of rate of height growth in ponderosa pine. For. Sci. 7: 24-.34. 1976. The use of vegetation in assessing the pro- ductivity of forest lands. Bot. Review 42: 115-143. Deitschman, G. H., and a W Greene 1965. Relations between western white pine site index and tree height of several associated species. USDA Forest Service, Res. Pap. INT-22. 27 pp. DeVelice, R L. J A Ludwig, W H Moir, and F Rgnco, Jr. 1986. A classification of forest habitat types of northern New Mexico and southern Colo- rado. USDA Forest Service, Gen. Tech. Rept. RM-131..59pp. Edminster. C B 1978. RMYLD: computation of yield tables for evenraged and two-storied stands. USDA Forest Service, Res. Pap. RM-199. 26 pp. Fitzhugh. E L. W H Moir, J A Ludwig, and F Rgncg, Jr 1984. Forest habitat types in the Apache, Gila, and part of the Cibola National Forests. USDA Forest Service. Mimeo of manuscript in preparation. 145 pp. Hanks, J P , E L Fitzhugh, and S. R. Hanks. 1983. A habitat classification system for ponderosa forests of northern Arizona. USDA Forest Service, Gen. Tech. Rept. RM-97. 22 pp. HODGKINS, E j. 1956. Testing soil-site index tables in southwestern Alabama. J. For. .54: 261-266. Hoffman, L. J 1976. Height growth of Douglas-fir in relation to habitat types in northern Idaho. Un- published thesis. University of Idaho, Moscow. .30 pp. Husch, B., C. Miller, and T W. Beers. 1972. Forest mensination. Ronald Press Company, New York. 410 pp. Ilvessalo, Y 1927. Methods for preparing yield tables. Silva Fenn. 5: 1-30. 1937. Growth of natural stands in central North- Suomi, Finland. Commun. Inst. For. Fenn. 24: 1-149. Jones. J R 1969. Review and comparison of site evalua- tion methods. USDA Forest Service, Res. Pap. RM-75. 19 pp. Larson. F R . and C O Minor. 1983. AZPIPO: a simula- tor for growth and yield of ponderosa pine in Ari- zona. Arizona For. Note No. 20, Sch. of Forestry, Northern Arizona University, Flagstaff. 13 pp. L.WSER, E F 1974. Vegetation classification: its applica- tion to forestry in the northern Rocky Mountains. J. For. 72:354-357. M.\thiasen. R L., E. a. Blake, and C B Edminster. 1986. Estimates of site potential for Douglas-fir based on site index for several southwestern habi- tat types. Great Basin Nat. 46(2): 277-280. Meyer, W. H. 1961. Yield of even-aged stands of pon- derosa pine. USDA Forest Service, Tech. Bull. 630. 59 pp. Minor. C O 1964. Site-index curves for young-growth ponderosa pine in northern Arizona. USDA Forest Service, Res. Note RM-.37. 8 pp. Moir. W H., and J. A. Ludwig. 1979. A classification of spruce-fir and mixed conifer habitat types of Ari- zona and New Mexico. USDA Forest Service, Gen. Tech. Rept. RM-207. 47 pp. Monserud, R. A. 1984. Height growth and site index curves for inland Douglas-fir based on stem analy- sis data and forest habitat type. For. Sci. 30: 943-965. 1985. Comparison of Douglas-fir site index and height growth curves in the Pacific Northwest. Canadian J. For. Res. 15:673-679. Pfister, R D. 1976. Land capability assessment by habi- tat types. Pages 312-335 in America's renewable resource potential — 1975: the turning point. Pro- ceedings of the 1975 National Convention Society of American Foresters, Washington, D.C. Pfister, R. D , and S. Arno 1980. Classifying forest habi- tat types based on potential climax vegetation. For. Sci. 26:52-70. Pfister, R. D , B Kovalchik. S. Arno. and R. Presby. 1977. Forest habitat types of Montana. USDA Forest Service, Gen. Tech. Rept. INT-.34. 174 pp. Pfister. R D.J Schmautz, D On, and'C Brown 1971. Management implications by habitat types. USDA Forest Service, Northern Region Training Manual. Mimeo. 30 pp. 472 Great Basin Naturalist Vol. 47, No. 3 Roe, a L. 1967. Productivity indicators in western larch forests. USDA Forest Service, Res. Note INT-59. 4 pp. Schubert, G. H. 1974. Silviculture of southwestern pon- derosa pine: the status of our knowledge. USDA Forest Service, Res. Pap. RM-123. 71 pp. Shepperd, W D , R R Alex.'VNDER, and F Ronco. Jr 1983. Silviculture of ponderosa pine in the central and southern Rocky Mountains. USDA Forest Service, RM-TT-4. 36 pp. Spencer, J. S. 1966. Arizona's forests. USDA Forest Ser- vice, Res. Bull. INT-5. 56 pp. Stage, A R. 1973. Prognosis model for stand develop- ment. USDA Forest Service, Res. Pap. INT-137. 32 pp. 197.5. Prediction of height increments for models for forest growth. USDA Forest Service, Res. Pap. INT-164. 20pp, Stanek, W 1966. Relative quality of the major forest associations of the southern British Columbia inte- rior for growth of lodgepole pine, Engelmann spruce, Douglas-fir, and alpine fir. For. Chron. 42: .306-313. Steele. R . R D Pfister, R A Ryker, and J A Kittams 1981. Forest habitat types of central Idaho. USDA Forest Service, Gen. Tech. Rept. INT-114. 1.38 pp. Vincent, A B 1961. Is height/age a reliable inde.x of site? For. Chron. 37: 144-150. YOUNGBLOOD, A P . AND R A Mauk. 1985. Coniferous forest habitat types of central and southern Utah. USDA Forest Service, Gen. Tech. Rept. INT- 187. 89 pp. SOIL NEMATODES OF NORTHERN ROCKY MOUNTAIN ECOSYSTEMS: GENERA AND BIOMASSES T. Weaver' and J. Smolik" ABSTii^CT. — Soil nematode populations were larger and more diverse in two grasslands than in three forests of the northern Rocky Mountains. As we moved from Festuca idahoensis grassland through progressively higher zones of vegetation dominated b\ Artemisia tridentata, Populus tremiiloides. and Psetidotsu^a meiiziesii. and then to Abies lasiocarpa forests, numbers of nematode genera declined from 31 to 26 to 20 to 21 to 13; numbers of individuals in the top 50 cm of the soil were 6.0, 5.3, 1.7, 1.5, and 1.6 million/m", and biomasses ot nematodes in the top 50 cm of the soil were 0.83, 0.88, 0.58, 0.35, and 0. 19 g/m~. Biomasses of nematodes were often well correlated with root biomass as well as soil depth; of the nematodes in the 0-50-cm horizon, 38 to 70% were in the 0-20-cm layer. The effects of light grazing on nematode populations were small or nonexistent. While the plant component of major Rocky Mountain communities has been character- ized (Mueggler and Stewart 1979, Pfister et al. 1977), their soil nematode composition has not been described (cf. Table 1). To repair this deficiency, we have compared the generic composition, densities (number/m"") by feed- ing group, and biomasses (g/m") by feeding group of nematodes in major vegetation types spanning the altitudinal zone from foothills to timberline. On a complex gradient of increas- ing altitude, increasing precipitation, and de- creasing temperature (Weaver 1980), these include: Festuca idahoensis grasslands, Artemisia tridentata shrublands, Populus tremuloides forests, Pseiidotsu^a menziesii forests, and Abies lasiocarpa forests. Strengths of our study include the diversity of ecosystems compared, the use of uniform methods to compare them, and the sampling of a thicker soil layer (0-50 cm) than is usually studied (cf. Table 1). Methods To describe soil nematode populations as- sociated with Rocky Mountain vegetation, we sampled soils under near-climax communities representing major vegetation zones along the altitudinal gradient. From foothills up- ward, these were Festuca idahoensis- Agropyron caninurn, Artemisia triden- tata-Festuca idahoensis, Popuhis tremu- loides-Poa pratensis, Pseudotsuga men- ziesii-SympJioricarpos alba, and Abies lasio- carpa-Vaccinium scoparium habitat types. All stands were in the Bridger Mountains, within 22 km of Bozeman, Montana, and at altitudes of 2,330, 1,570, 1,810, 1,650, and 1,820 m, respectively. Pfister etal. (1977) and Mueggler and Stewart (1979) describe the plant associations indicated. Soil water regimes of all stands (Weaver 1977) and nutri- ent regimes of the Arteinisia, Pseudotsuga, and Abies stands (Weaver and Forcella 1979) have been characterized previously. The soils were classified as Typic Cryoborolls, Pachic Argiborolls, Udic Haploborolls, Typic Hap- loborolls, and Mollic Cryoboralfs, respec- tively. Soil cores used in characterizing the ne- matode populations were collected in all stands on 30 July 1973. A second sample was collected at the Festuca-Agropyron site on 2 October 1972. At each site six cores were taken using a soil-sampling tube with a 2. 1-cm inside diameter. Cores were taken to a depth of 50 cm at 3-m intervals along a line passing through the stand studied. Each core was di- vided into 10-cm increments: 0-10 cm, 10-20 cm, etc. The cores were refrigerated at 4 C until they were analyzed. Nematodes were extracted from the soil by wet screening followed by Baermann funnel extraction (Christie and Perry 1951). The effi- ciency of the wet screening was determined Biolog\ Department, Montana State University, Bozeman. Montana 59717 "Plant Science Department, South Dakota State University. Brookings, South Dakota .57007 473 474 Great Basin Naturalist Vol. 47, No. 3 Table 1. Nematode numbers ; imd biomasses in various vegetation types. Vegetation type Densities Biomasses Depth' Source (millions/m^) (g/m-) (cm) Desert Mojave 0.4-1.1 0.1-0.2 30 Freckman et al. 1975 Colorado 0..5-0.8 0.1 30 Freckman et al. 1975 Grasslands Andropogon 0.1-0.3 0.2-1.5 20 Coleman 1971 0.1-0.5 0.5-3.0 80 Coleman 1971 Phalaris 0.1-0.3 — 25 King and Hutchinson 1976 Swiss — 5.0 15 in Banage 1963 Danish 4-20 6-18 5 in Banage 1963 Irrigated field 0.8-1.7 0.15 20 Freckman et al. 1975 Artemisia- Agropyron 4.7-5.3 0.4-0.5 40 Smolik and Rodgers 1976 Agropyron-Biichloe 3.8-7.9 0.5-1.8 60 Smolik 1974 Deciduous forests Beech 0.4 0.08 6 Phillipson 1977 Beech 1.1 0.28 6 Yeats 1972 Beech 12 4.0 25 in Banage 1963 Oak 30 15 25 in Banage 1963 Oak-hornbeam — 4-13 ? Saly 1975 Liriodendron 1-6 0.6-1.4 16 McBrayer et al. 1977 Coniferous forests Picea 0.01 — ? Eroshenko 1976 Pseudotsuga 1.3 — 16 McBrayer et al. 1977 Moor Danish 1-3 1.5-4.5 5 in Banage 1963 British 2-3 0.5-0.8 6 Banage 1963 Tundra Bare soil 0.07 0.3 85 Kuzmin 1976 Bare soil 0.01 — 10-100 Chernov et al. 1977 Moss lichen 2-4 — 10-100 Chernov et al. 1977 Moss 0.5 — 6 Spaull 1973 Moss 0.6-3 6-31 85 Kuzmin 1976 Herb-grass 0.8-8 1.1-7.5 85 Kuzmin 1976 Deschampsia 7.4 — 6 Spaull 1973 Sampling was from the top of the soil to the depth given by reextracting the soil sample. Efficiency of the Baermann funnel was established by ex- amining approximately 10% of the residues to determine the number of nematodes that failed to pass through the screen. Nematode numbers were then corrected for the overall extraction efficiency, which varied with vege- tation type from 60 to 70%. Density estimates were made by counting the number of ne- matodes (60X magnification) in three 1-ml aliquots of a 50-nil suspension on Scott hook- worm larvae counting slides. Biomass esti- mates were made following the method of Andrassay (1956) and were converted to dry weight by multiplying by 0.25 (Smolik 1974). Generic identifications and measurements for biomass determinations were obtained from permanent mounts (Thorne 1961) of approxi- mately one thousand randomly selected indi- viduals. Nematodes were assigned to feeding groups bv reference to standard catalogues listed by Smolik (1974). Although our study is based on samples taken on one date near midsummer (30 July 1973), we believe the data fairly approximate the general numbers, biomasses, and generic compositions that might be found in another summer month or in the same month of an- other year. The following statements support our belief (1) Most studies in which succes- sive samples have been taken from sites with undisturbed vegetation show relatively small differences (less than a factor of two) between nematode populations in successive summer months: differences observed by Coleman (1971), King and Hutchinson (1976), Phillip- son et al. (1977), Banage (1963), and Ferris and McKenry (1976) were not statistically sig- nificant; some differences observed by Yeats (1972) were statistically significant; differ- July 1987 Weaver, Smolik: Soil Nematodes 475 Table 2. Nematode genera present in five vegetation types. Feeding group and genus Community type FEID' FEID^ ARTRi POTR' PSME' ABLA' Herbivore Dittjlcnchus + + + + + + HeUcotijlcnchus + + + + + + Merlinius + + + + + + Ttjlcncliiis + + + + + + Tijh'nchorhijchus + + + + + Aglcnchus + + + + Nothottjlenchtts + + + + DonjhiimeUtts + + + Paratylenchus + + + Tylencholaimelltis + + + Criconemoides + + Enchoddus + + Hemicijcliophora + + Pratyh'nchoides + Axonchitim + Diphtlicrophora + + Xiphiucma + + Trichodorus + + Tijlcncholaimus + + Bolcodorus + + + Leptonchus + Number of genera 15 15 13 IT ~9 4 Predaceous Aporcdaimellus + + + + + + Eudorylaimus + + + + + Dorylaimoides + + + + Nygolaimus + + + Thomis + + Mesodorylaimiis + Tripyla + Myhmchuhis + + Miconchus + Mononchus + + + Number of genera Microvore Acroheloides + + + + + + Plectus + + + + + + Aphelenchoides + + + + + Panagrolaimus + + + + Aphclcndius + + + + Eucephalobus + + + + Acrobeles + + + Bastiani + Prismatolaimus + Wilsonema + Anaplcctus + + + Chiloplacus + + + Rhabditis + + Cervidelhis + + + Cephalobus + + + + Number of genera 11 13 9 5 8 4 Total genera 31 34 26 20 21 13 Ungrazed vegetation types were Festuca idahoensis (FEID), Artemisia tridentata (ARTR), Populus tremuloides (POTR), Pseudotsuga memiesii (PSME), and Abies lasiocarpa (ABLA). Grazed vegetation of an adjacent Festuca idahoensis stand (FEID). 476 Great Basin Naturalist Vol. 47, No. 3 NEMATODES MILLIONS /«- FEIO ARTR POTR PSME ABLA NEMATODES GM/M Fig. I. Nematode numbers and biomasses in five vege- tation types; A, Nematode numbers in millions; B, Ne- matode biomasses in grams per square meter. The first bar in each type presents herbivore data, the second microvore data, and the third predator data. Each bar is subdivided into a shaded portion and four clear portions below it indicating successively lower 10-cm horizons. Above the first bar is an unshaded bar indicating total nematode numbers or biomasses. The vegetation types are Festuca idahoensis (FEID), At-temisia tridentata (ARTA), Popidus treimdoides (POTR), Pscudotsuga men- ziesii (PSME), and Abies lasiocarpa (ABLA). ences observed by Smolik and Rodgers (1976) and McBrayer (1977) might have been statisti- cally significant if they had been tested. (2) Numbers and biomasses measured in our Fes- tuca idahoensis grassland changed little with season; on 2 October 1972, for example, they were 1.2 times as large as those measured on 30 July 1973. (3) Weather data from a station representative of the region (US DC 1973, Bozeman MSU, Montana) were normal: April-July precipitation was 100% of normal, June precipitation was 140% of normal, and July precipitation was 33% of normal; the av- erage May temperature was normal, the aver- age June temperature was 1.2 C above nor- mal, and the average July temperature was 0.8 C above normal. Root biomass data correlated with ne- matode population parameters were mea- sured by coring, washing out small roots (< 1 mm), and determining their ash-free weights. Detailed methods and results were reported by Weaver (1977). Results and Discussion DiVERSiTi .- — The generic diversity of plant- feeding and microbe-feeding nematodes de- clined as we moved from steppelands {Festuca and Arteinisia) to a Populus forest to conifer- ous forests {Fseudotsuga and Abies), but the diversity of predaceous nematodes remained constant (Table 2). The diflPerence appears to be due principally to the failure of steppe genera under forest conditions, since the number of genera endemic to steppelands (15) was three times greater than the number re- stricted to forest lands (5). The major ne- matode genera appearing in each vegetation type are listed in Table 2. Density'. — Total numbers of nematodes present in the upper 50 cm of the soil declined from grasslands to forests (Fig. 1); they were 6.0, 5.3, 1.7, 1.5, and 1.6 million/m^ in Fes- tuca, Artemisia, Populus, Fseudotsuga, and Abies stands, respectively. The nematodes were similarly partitioned into plant-feeders, microbe-feeders, and predators in steppe vegetation (55, 38, and 7%, respectively) and coniferous forests (65, 25, and 10%, respec- tively). Given differences in the methods used and the depths considered, our data generally agree with those from other regions (Table 1). Note especially that Egunjobi (1971) and Raz- zhivin (1976) also found lower nematode den- sities in forests than in grasslands and that Novikova (1970) also observed similar ne- matode densities in deciduous and coniferous forests. Bio\L\ss. — Total nematode biomasses present in the upper 50 cm of the soil declined from grasslands to forests (Fig. 1, Table 3); they were 0.83, 0.88, 0.58, 0.35, and 0.19 g/m" in Festuca, Artemisia, Populus, Fseudo- tsuga, and Abies vegetation, respectively. These biomasses are similar to those reported in other regions (Table 1). The nematodes were similarly distributed among plant-feed- ers, microbe-feeders, and predators in steppe communities (35, 28, and 37%, respectively) and coniferous forests (35, 15, and 50%, re- spectively). These masses may be better ap- preciated by comparing them with the July 1987 Weaver. Smolik: Soil Nematodes 477 Table 3. Mean' nematode and root biomasses (g/m~) ol five vegetation types." Soil depth (cm) CV' ^A 0-10 10-20 20-30 30-40 40-50 0-50 FEID herbivore 0.087 0.079 0.056 0.065 0.035 0.322 0.10 0.59 microvore 0.080 0.066 0.049 0.040 0.029 0.266 0.13 0.83** predator 0.056 0.056 0.042 0.061 0.033 0.247 0.05 0.14 total 0.223 0.201 0.147 0.166 0.097 0.835 0.06 0.62** root 902.0 391.0 143.0 51.0 95.0 158.2 0.01 ARTR herbivore 0.056 0.061 0.044 0.075 0.047 0.283 0.12 0.01 microx'ore 0. 102 0.033 0.019 0.035 0.014 0.203 0.16 0.87** predator 0.070 0. 102 0.059 0.093 0.075 0..399 0.14 0.00 total 0.228 0. 196 0.122 0.203 0. 1.36 0.885 0.03 0.55* root 202.0 118.0 58.0 54.0 44,0 476,0 0.03 POTR herbivore 0.060 0.021 0.012 0.021 0.021 0, 1.35 0.35 0.90** microvore 0.022 0.004 0.010 0.010 0,006 0,052 0.22 0.68** predator 0.017 0.040 0.038 0.065 0.079 0,239 0.22 0.56* total 0.099 0,064 0.060 0.096 0, 106 0,426 0.19 0.24 root 355 409 37 12 23 836 0.23 PS ME herbivore 0.083 0.037 0.033 0.007 0,009 0.169 0.19 0.96** microvore 0.021 0.014 0.008 0.007 0.003 0.053 0.21 0.80** predator 0.064 0.026 0.028 0.007 0.005 0. 130 0.17 0.96** total 0.168 0.077 0.069 0.021 0.017 0.352 0.13 0.95** root 231 81 88 42 48 490 0.14 ABLA herbivore 0.010 0.005 0.008 0.003 0,004 0.030 0,48 0.67** microvore 0.021 ().()()6 0.001 0.004 — 0.032 0,36 0.90** predator 0.064 0.041 0.020 — — 0. 125 0,42 0.95** total 0.095 0.052 0.029 — — 0,176 0.35 0.99** root 245 123 75 45 57 545 0.06 'Average coefficients of variation for herbivore-microvore-predator and root data are FEID (19-1%), ARTR (28-40%), POTR (55-33%), PSME (41-45%). and ABLA (76-40%). ^Vegetation types are FEID - Festuca idahoensi.'i. ,ARTR Artcmista tridentata. POTR - Popuhn, trcinuldidcs. PSME - Pseudotsus.a menziesii. and .\BLA = Abies lasiocarpa. Coefficients of variation (SD/.\) for the 0-50 cm layer ■The square of the correlation coefficient (r~) of nematode biomass against root biomass by layer Statistical significance is indicated by asterisks: ** ^ significant at the 1% level, and * - significant at the ,5% level biomass of cattle grazing in a Festuca meadow, that is, apprcximately 4-5 g/ni" on an annual basis. CoMMUMT\' structure, — The functional composition — microvore, phytovore, preda- tor— of the nematode population showed no consistent changes with changes in commu- nity type. Phytovores comprised about 60% of the herbivore (microvore and phytovore) biomass; this proportion was 56, 58, 67, 78, and 50% in Festuca, Artemisia, Populus, Pseudotsuga, and A/?ie.s communities, respec- tively. Predator weights usually exceeded 50% of the herbivore weights; they were 42, 82, 216, 60, and 197% in Festuca, Artemisia, Populus, Pseudotsuga, and Abies communi- ties, respectively. The large predator/herbi- vore ratios suggest that herbivores turn over rapidly, that the predators consume other foodstuffs including plant material (Smolik 1974), and/or that the predators have low res- piration rates (Klekowski et al. 1972). The pyramid (predator/herbivore ratio) of biomass is less steep than the number pyramid be- cause predators (0.96 g/million) are nine times larger than herbivores (0.11 g/million). For comparison, the weight of a predatory wolf is about 40 kg, and his herbivorous prey range in weight from 0.03 kg (voles) to 5 kg (rabbits) to 100 kg (deer) to 700 kg (bison) (Burt and Grossenheider 1964). Environmental factors correlated WITH NEMATODE DISTRIBUTION. — We do not know what environmental factors are respon- sible for the decline in nematode diversity, numbers, and biomass from grasslands to forests. Evidence suggesting that low temper- atures may be the controlling factor is summa- rized below. (1) Soil temperatures, like ne- matode numbers, are lower under our forests than in adjacent (or lower) grasslands (Munn et al. 1979). (2) Our data (Fig. 1, Table 3) are inconsistent with other obvious hypotheses. Soil water, said to favor nematodes (McBrayer 478 Great Basin Naturalist Vol. 47, No. 3 et al. 1977), becomes more available as one moves from nematode-rich steppelands to nematode-poor forests (Weaver 1977). Soil or- ganic matter and pH are lower in nematode- poor coniferous forests, but not in nematode- poor aspen forests, than in nematode-rich steppelands. Though they are high in nematode-rich Festuca grasslands, root bio- masses of the nematode-rich Aftemisia com- munity did not exceed those of the nematode- poor forests. Nutrient elements (e.g., N, P, K) are probably available in larger quantities in nematode-rich steppelands, and in nematode- poor aspen forests, than in nematode-poor coniferous forests (Weaver 1979). (3) Egun- jobi's (1971) observation that nematodes were fewer in forests of New Zealand than in adja- cent cleared land planted to grasses supports the temperature hypothesis: soils of the cleared area probably differ little in pH, or- ganic matter content, nutrient availabilities, water availabilities, etc., but they are proba- bly warmer. (4) An alternate, but doubtful, hypothesis is that trees have evolved nematode-inhibiting structures or chemicals, perhaps in response to a greater initial suscepti- bility associated with their relatively long lives. Total nematode biomasses decreased regu- larly with depth in Festuca, Pseudotsuga, and Abies communities, but not under Artemisia and Populus (Table 3). Of nematode biomasses in the 0-50-cm horizon, the 0-20- cm horizon contained 51, 48, 38, 70, and 67% in Festuca, Artemisia, Populus, Pseudotsuga, and Abies, respectively. Similar decreases were observed by Coleman (1971), who em- phasized the need for examination of subsur- face horizons, as well as by Smolik (1974) and Ferris and McKenry (1976). One might expect nematode biomasses to be well correlated with root biomasses, which also decline with depth, either because roots serve as a food source or because warm, moist, oxygen-rich conditions favoring roots should favor nematodes as well. The correlation be- tween microvores and root biomass data from the same sites (Weaver 1977) is highly signifi- cant in every vegetation type (Table 3). The correlation of both herbivore and predator biomasses with root biomass was significant in forest communities, but not in steppe com- munities (Table 3). Small differences in nematode numbers be- tween grazed and ungrazed parts of our meadow, if they are biologically significant, could be due to light grazing or to the rela- tively shallow soils of the grazed plots. Total numbers were significantly less at the 1% level in October 1972 (grazed 6.3 million/m , ungrazed 7.2 million/m") and in July 1973 (grazed 4.8 million/m", ungrazed 6.0 million/ m"). Total autumn 1972 biomasses were 1.04 g/m" in the grazed area plots and 1.05 g/m in ungrazed plots; total summer 1973 biomasses were 0.72 g/m" grazed and 0.83 g/m" un- grazed. Numbers of plant-feeders were lower in the grazed plot in both years and signifi- cantly so in 1972. Numbers of microbe- feeders were significantly greater in the grazed area in 1973, but were lower in 1972. Numbers of predators were lower in the un- grazed area in 1972, higher in the ungrazed area in 1973, and did not differ significantly between treatments in either year. Plant- feeding nematode biomasses were apparently reduced by grazing in a South Dakota Agropy- ron smithii-Biichloe dactijloides grassland (Smolik 1974), but not in a Washington Artemisia tridentata-Agropyron spicatum grassland (Smolik and Rodgers 1976). Conclusions Soil nematode populations were more dense, heavier, and more diverse under steppe than forest vegetation. The decline oc- curred under both deciduous and coniferous vegetation. The drop in soil temperature may be a major influent. Grazing is apparently not. Within a soil, nematodes are most numer- ous in surface horizons. This could be due to conditions which favor roots, to the presence of roots, or to the presence of organisms asso- ciated with the roots. Acknowledgments The studv was supported by NSF Grant BMS-73-02027-A02 to the Grassland Biome of the US IBP. J. Howell and F. Forcella as- sisted with the soil coring. Literature Cited Andrassy, I. 19.56. Die Rauminhalts unci Gewichts- bestimmung der Fadenwurmer (Nematoden). Acta Zoo]. Acad. Sci. Hung. 2: 1-L5. July 1987 Weaver. Smolik: Soil Nematodes 479 Banage, W 1963. The ecological importance of free- living nematodes with special reference to those of moorland soil. J. Animal Ecology 32: 133-140. Burt, W., and R Grossenheider 1964. A field guide to the mammals. Houghton-Mifflin, Boston. 284 pp. Chernov. J.. B. Striganova, and S. Ananjeva 1976. Soil fauna of the polar desert at Cape Cheluskin, Taimyr Peninsula, USSR. Oikos 29: 175-179. Coleman, D 1971. Numbers and biomass of soil ne- matodes of two South Carolina old fields. Amer. Midi. Nat. 85: 262-265. Cristie, J., AND V Perry 1951. Removing nematodes from soil. Proc. Helminth. Soc. Washington 18: 106-108. ECUNJOBI. O 1971. Soil and litter nematodes of some New Zealand forests and pastures. New Zealand J. Science 14: 568-579. Eroshenko. A, andG Truskova 1976. Population den- sity and biomass of nematodes in spruce forests of central Sikhote-Alin. Zool. Zh. 55; 670-674. Bio- logical Abstracts 63: 19632. Ferris. H.. and M. McKenry. 1976. Nematode commu- nity structure in a vine\ard soil. J. Nematologv 8: 131-137. Freckman, D . R Mankau, and H Ferris 1975. Ne- matode community structure in desert soils: ne- matode recovery. J. Nematology 7: 343-346. King. K., and K Hutchinson 1976. The effects of sheep stocking on the abundance and distribution of mesofauna in pastures. J. Appl. Ecol. 13: 41-55. Klekowski, R . L Wasilewsk.\, and E Paplinska 1972. Oxygen consumption by soil-inhabiting ne- matodes. Nematologica 18: 391-403. KUZMIN, L. 1976. Free-living nematodes in the tundra of western Taimir. Oikos 27: 501-505. McBrayer, J.J Ferris. L Metz. C Gist. B Cornaby. Y KiT.\ZAWA. T KiT.\ZA\VA. J Wernz. G Kranz. and H Jensen 1977. Decomposer invertebrate popu- lations in U.S. forest biomes. Pedobiologia 17: 89-96. Mueggler. W , and W Stewart 1979. Grassland and shrubland habitat types of western Montana. USDA Forest Service Gen. Tech. Report INT-66. Intermountain Forest and Range E.xperiment Sta- tion, Ogden, Utah. 154 pp. Munn, L., B. Buchanan, and G Nielsen 1978. Soil tem- peratures in adjacent high-ele\ation forests and meadows of Montana. Soil Sci. Soc. Amer. J. 42: 982-983. Novtkova, S 1970. Fauna and distribution of nematodes in forests litter. Zool. Zh. 49: 1624-1631. Biologi- cal Abstracts 52: 77213. Pfister. R.. B Ko\ alchik, S Arno. and R Presby 1977. Forest habitat types of Montana. USDA Forest Service Gen. Tech. Report INT-34. Ogden, Utah. 174 pp. Phillipson, J , R Abel. J Steel, S. Woodell 1977. Ne- matode numbers, biomass, and respiratory metabolism in beech woodlands: Wv tham Woods. Oecologia 27: 141-155. R\ZZHI\IN. A 1976. Nematodes in soils of the Zailiyskiy and Dzungarian .\la Tau. Zool. Zh. 55; 1558- 1560. Biological Abstracts 64: 55719. Saly. a 1975. Study of biomass and caloric value of the soil nematode populations in hornbeam-oak wood in Bab. Biologia 30: 615-620. Biological Abstracts 61: 18743. Smolik. J. 1974. Nematode studies at the Cottonwood site. US IBP Grassland Biome Tech. Report 251. Colorado State Universit\ , Fort Collins. 80 pp. Smolik. J , and L Rogers 1976. Effects of cattle grazing and wildfire on soil-dwelling nematodes of the shrub-steppe ecosvsteni. J. Range Manage. 29: 304-306. Spaull, V 1973. Qualitative and quantitative distribution of soil nematodes of Singy Island, S. Orkney Is. Br. Antarct. Survev Bull. 33; 47-177. Biological Abstracts 58: 26454. Thorne. G 1961. Principles of nematology. McGraw- Hill, New York. USDC 1973. Climatological Data, Montana. USDC- NOAA Environmental Data Service, Asheville, North Carolina. We.-wer, T 1977. Root distribution and soil water regimes in nine habitat t\pes of the northern Rocky Mountains. In: J. Marshall, The below- ground ecosvstem. Range Sci. Dept. Sci. Series 26. Colorado State University, Fort Collins. 351 pp. 1979. Changes in soils along a vegetation-altitudi- nal gradient of the northern Rocky Mountains. In: T. Youngberg, ed., Proc. 5th N. Amer. Forest Soils Conf (Fort Collins). Oregon State Univer- sit> Press, Corvallis. 1980. Climates of vegetation types of the northern Rock\' Mountains and adjacent plains. Amer. Midi.' Nat. 103; 392-398. We.wer.T . andF Forcella 1979. Seasonal variation in soil nutrients under si.x Rock\ Mountain vegeta- tion types. Soil Sci. Soc. Amer. J. 43; 589-593. Yeats, G. 1972. Nematoda of a Danish beech forest: I, methods and general anahsis. Oikos 23; 178-189. EVIDENCE FOR VARIABILITY IN SPAWNING BEHAVIOR OF INTERIOR CUTTHROAT TROUT IN RESPONSE TO ENVIRONMENTAL UNCERTAINTY Rodger L. Nelson', William S. Platts', and Osborne Casey^ Abstract — The fluctuating characteristics (numbers, biomass, condition, and young-adult ratios) of the Lahontan (Humboldt) cutthroat trout population in Chimney Creek, Nevada, are discussed in relationship to the unpredictable and unstable habitat in which the population occurs. One possible means of adapting to environmental capriciousness, staggered spawning, occurred during 1982, and clues as to the cause of" this unusual event are sought by examining the runoff hydrographs of a nearby watershed for 1981 through 1984. The management values of the environmental tolerance of these native trout with respect to restoring viable trout fisheries in degraded Great Basin streams are also considered. It can be reasonably assumed that organ- isms are adapted to the habitats in which they occur naturally. Consequently, persistence through time in a natural, yet apparently hos- tile, environment provides empirical evi- dence that a species has developed a success- ful adaptive strategy with respect to prevailing conditions. Mechanisms underly- ing such adaptation, however, are poorly un- derstood, and conventional thinking may be misleading. For example, if we expect adapta- tion to occur through specialization, we may find it difficult to explain an organism's adap- tation to an environment characterized by un- predictable events. In such situations, in fact, the more profitable adaptive strategy may be maintenance of a high degree of environmen- tal tolerance, such as greater niche breadth (Valentine 1969). It may, therefore, be advan- tageous for a population to maintain consider- able genetic flexibility (Thoday 1959). Genetic flexibility will serve to ensure persistence during periods of marginal habitat conditions and will confer the ability to rapidly exploit unusually favorable conditions; such a popula- tion will be resilient but potentially highly unstable (Holling 1973). Such genetic flexibil- ity may be manifested behaviorally and may include reproductive behavior (Wellington 1964). Accordingly, we might expect some apparently unusual population behavior in re- sponse to unusually capricious environmental events. The interior basins of the western United States offer worthy environments in which to study adaptations of native riverine fishes to apparently hostile situations. Climatic condi- tions are highly unstable over time, and stream flow patterns, though manifesting some seasonal regularity, are often unpre- dictable in timing, duration, and magnitude. Recent studies of Great Basin streams have revealed exceptional precipitation and conse- quent runoff events during the past several years (Platts, Gebhardt et al. 1985). Of partic- ular interest in this regard are the cutthroat trout {Solmo clarki ssp.) native to the upper Humboldt River Basin in northeastern Nevada. Taxonomically, these trout are gen- erally accorded identity with the Lahontan cutthroat (S. c. henshawi), native to the west- ern portion of the Lahontan Basin, comprising the Truckee, Walker, and Carson River drainages of northwestern Nevada and east- ern California. Recent work, however, has suggested that it would be more appropriate to assign the populations endemic to the up- per Humboldt River system separate sub- specific status (Behnke 1979, Platts and Nel- son 1983). In this report, we have adopted Behnke's (1979) tentative classification of these fish as Humboldt cutthroat trout. Habitat requirements of the riverine cut- throat trout in the upper Humboldt drainage are nearly as uncertain as taxonomic designa- tion. Coffin (1982), echoing the words of 'USDA Forest Service. Intermountain Research Station, Forestn. Sciences Laborator\. Boise, Idaho 8,3702. ^USDI Bureau of Land Management, Reno. Nevada 89.520. 480 July 1987 Nelson etal: Cutthroat Trout Behavior 481 Raleigh and Duff" (1981), indicates that opti- mal riverine cutthroat trout habitat is characterized by clear, cold water; a silt-free rockx sub- strate in riffle-run areas; an approximateK 1:1 pool-riffle ratio with areas of slow, deep water; well \egetated stream banks; abundant instream cover; and relativel\ stable water flow, temperature regimes, and stream banks. While we have no quarrel with the general applicability of such a statement, it seems too simplistic for conditions characterizing Great Basin streams; riverine populations in the up- per Humboldt River Basin persist and even thrive in the absence of anv of these criteria (Behnke 1979, Platts and Nelson 1983). Cutthroat trout are typically regarded as small-stream spawners (Platts 1960, Van De- venter and Platts in press), and both lacus- trine and riverine fish may ascend small streams to spawn. Whether this leads to inter- breeding between migratory and resident populations is unclear but can probably be assumed. The spring spawning habit allows utilization of small, intermittent streams dur- ing high flow periods rather than during unde- pendable late summer and fall when adequate flows are less predictable. Timing of upstream migration may therefore be triggered by peak flows to optimize the resource. Because flood- ing may be detrimental to egg survival (See- grist and Card 1972) and invertebrate food production (Elwood and Waters 1969), how- ever, spawning must ideally occur late enough in the runoff period to minimize the possibility of an unexpected late-season flood. Correspondence between peak flows and up- stream spawning migration has been reported for rainbow trout (Salmo gairdncri Richard- son) in Sagehen Creek, California, bv Erman and Hawthorne (1976), and Coff"in (1982) stated that Lahontan cutthroat trout ascend streams as flows and water temperatures rise in the spring. Sigler et al. (1983) showed that peak spawning migration of Lahontan cut- throat trout from Pyramid Lake, Nevada, oc- curred between April and May but over a range of February to July. Lea (1968) reported spawning runs of Lahontan cutthroat trout leaving Independence Lake, California, be- ginning as early as mid-June and continuing as late as August during years with high stream flow conditions. Another very closely related interior subspecies, the Bonneville cutthroat (S. c. Utah ), has been reported to spawn from late May to mid- to late June, with spawning beginning in the lowest stream reaches and progressing upstream (May et al. 1977). This paper describes the characteristics of the population of Humboldt cutthroat trout in Chimney Creek, Nevada, during four years of "abnormal" spring flows. We propose this be- havior as evidence suggesting plasticity in re- productive behavior as an adaptation to a hos- tile and capricious environment. Several mechanisms for this adaptive behavior are dis- cussed, and suggestions for future study are proffered. Study Area Chimney Creek is a small, occasionally in- termittent tributary of Mary's River in north- eastern Nevada. Situated approximately 1,950 m above sea level, Chimney Creek serves as a nursery stream for migratory cut- throat trout in Mary s River and also supports a small resident population; no other fish spe- cies are present (Platts, Torquemada et al. 1985). Taxonomic studies of the resident fish have not been conducted, but individuals from Mary s River have been reported as pure Humboldt strain, as have individuals from nearby "T" Creek (Coff"in 1982). Climatic conditions around Chimney Creek are typical of the northern Great Basin, with cold, snowy winters and hot, dry sum- mers. Spring snowmelt during the past sev- eral seasons has resulted in dramatic alter- ations to the stream channel (Platts, Gebhardt et al. 1985, Platts, Torquemada et al. 1985). Coffin (1982) reported water temperatures as high as 17 C, and Platts, Torquemada et al. (1985) reported temperatures as high as 13 C as late as mid-October and diurnal fluctuation as high as 8 C. Our data^ show that water temperatures fluctuate drastically, even in winter, and can be as low as 0.4 C (Fig. 1). Methods Cutthroat trout population sizes in a 548-m section of Chimnev Creek were determined ■'Collected with Ryan Model J Thermographs Data on file USDA Forest Ser\ice, Intermountain Research Station, Forestp. Sciences Lab, Boise, Idaho The use of trade or firm names in this paper is for reader information and does not imply endorsement by the US Department of Agriculture of any product or service- 482 Great Basin Naturalist Vol. 47, No. 3 TEMPERATURES 30 STREAM .'7^ /mm 3 J^aJJs Cj~ a 25 Ma^_y'^ Jfji'ar \ 20 ih M IS llr W"'k 10 iV ^■■' \,v 5 ,\J Date (January 1 to k^arcti 1) A15 Date 15) Fig. 1. Midwinter water temperature fluctuations. Chimney Creek, Nevada, 1 January-1 March 1983. Fig. 2. Stream flow hydrograph.s from 1982 for Salmon Falls Creek and Marv s River, Nevada. annually from 1981 through 1984 during mid- August when flows were at their stable, mid- summer base level. Smith-Root Model SR-VII battery-powered, direct-current electrofishers were used to collect fish using the four-pass method of Platts et al. (1983). True population sizes were estimated using the maximum-likelihood depletion model (Platts et al. 1983, Van Deventer and Platts 1984). Trout were measured to the nearest millimeter, weighed to the nearest 0.1 g, and returned to the stream. All fish smaller than 75 mm were consid- ered to be young of the year (YOY) because they formed distinct size-class peaks on length-frequency plots (Bagenal and Tesch 1978); all others were classified as adults. Biomass was determined volumetrically and areally as the product of population estimates and their weight per cubic meter and per square meter of stream, respectively (Platts and Nelson 1983). Volumetric and areal densi- ties were similarly calculated as number per cubic meter and per square meter, respec- tively. We used volumetric estimates because we feel they more fully represent the three- dimensional character of the stream environ- ment than do conventional estimates based on surface area alone; however, areal estimates have been included for reference. We deter- 120 YEAR jsa^ 100 \ 80 1934 1 eo 40 20 y\j ^-^<:^^^iC_%:y:s^ n / A A' \ •&s2- ^T^- cl T^frrv^ - - - - .5 AIS U Date (February IS to Juno 15) Fig. 3. Stream flow hydrographs for February through 15 June for 1981 through 1984, Salmon Falls Creek, Nevada. mined average stream width and depth as described in Platts et al. (1983) to provide additional information about instream water levels as well as to provide density and biomass parameters. Volume was determined July 1987 Nelson ETAL: Cutthroat Trout Behavior 483 Table 1. Average stream width and depth, cutthroat trout weight, population, biomass, and density estimates, and young-adult ratios for Chimney Creek, Nevada, 1981 through 1984. Year of sample Factor 1981 1982 1983 1984 Mean stream width (m) 1.4 1.4 1.7 2.1 — Std error 0.04 0.04 0.04 0.06 Mean stream depth (m) 0.05 0.05 0.06 0.07 — Std error 0.002 0.002 0.002 0.003 Population size 53 462 420 280 — Std error 0.00 1.38 5.19 2.13 Mean weight (g) 19.2 3.2 7.1 10.4 — Std error 2.29 0.41 0.86 1.47 Biomass (g/m^) 30.40 37.63 56.09 37.22 — Std error 3.99 5.26 7.31 5.57 (g/nr) 1.30 1.93 3.26 2.52 — Std error 0.17 0.27 0.42 0.38 Density (no./m^) 1.58 11.80 7.91 3.58 — Std error 0.21 1.65 1.03 0.04 (no./m~) 0.07 0.60 0.46 0.24 — Std error 0.01 0.08 0.06 0.04 Young-adult ratio' 0 97 85 78 Determined from actual catches, not population estimates. YEAR joaj J9es jsaa loa^* 100 zoo Length Class This is arithmetically equivalent to the power function: Fig. 4. Cutthroat trout length-frequency distributions from Chimney Creek, Nevada, 1981 through 1984. simply as the product of mean width, mean depth, and study area length; surface area was length times mean width. Age and growth factors were determined in conventional fashion. Growth length-weight curves were established using the standard allometric relationship: Log (Weight) Constant + Coefficient x Log (Length) Weight Constant x (Length) CoefBcient (1) For annual comparisons, we have elected to refer to the coefficient in equation (1) as a growth coefficient to avoid confusion with other growth and production factors in the literature. Mean condition (K) was deter- mined using both the isometric relationship (2) and the allometric relationship (3) using the growth coefficient determined in equation (1): K = (10' X Weight)/(Length)' (2) K = (10' X Weight)/(Length)'''"''^"'-"' (3) The young-adult ratio (YAR) was computed as the proportion (in percentage) of the popula- tion contributed by YOY individuals. Because actual stream flow data for Chim- ney Creek were unavailable, we used the flows for nearby Salmon Falls Creek in the Snake River drainage to estimate runoff pat- terns. To account for possible variations over the area, runoff for upper Mary's River in 1982 was regressed against runoff in Salmon Falls Creek during the same period. Runoff pat- terns (not absolute flows) were essentially in- distinguishable (R" = 0.95; Fig. 2). Conse- quentlv, the hvdrographs generated for Salmon Falls Creek for 1981 through 1984 were considered to adequately reflect runoff 484 Great Basin Naturalist Vol. 47, No. 3 Table 2. Mean cutthroat trout lengths, weights, and population condition factors and growth factors for Chimney Creek, Nevada, 1981 through 1984'. Year of sample Factor 1981 1982 1983 1984 Adult mean length (mm) 127.8 163.6 151.2 154.3 — Std error 4.0.3 6.57 3.95 4.63 Adult mean weight (g) 19.2 52.2 38.2 43.1 — Std error 2.29 6.03 3.54 4.44 YOY mean length (mm) — 57.1 50.5 46.2 — Std error — 0.17 0.47 0.43 YOY mean weight (g) — 1.9 1.4 0.8 — Std error — 0.02 0.03 0.03 Mean isometric condition 0.77 1.00 1.01 0.80 — Adult only 0.77 1.13 0.95 0.97 —YOY only — 1.00 1.02 0.75 Mean allometric condition 0.47 0.56 l.,34 0.31 — Adult only 0.47 0.56 1..35 0.30 —YOY only — 0.56 1.33 0.31 Growth parameters — Coefficient .3.10 3.14 2.93 3.23 — Constant -12.29 12.10 11.26 -12.71 Determined from actual catches, not population estimates. patterns over the geographic region, includ- ing Chimney Creek. Mary s River stream flow data were obtained from U.S. Geological Sur- vey water resources data handbooks for Ne- vada (USDI 1982a, 1985a). Salmon Falls Creek, though larger than Chimney Creek, was selected because we had access to com- plete flow records in water resources data handbooks for Idaho (USDI 1982b, 1983, 1984, 1985b). Results Stream discharge patterns for the spring runoff periods of 1981 through 1984 were ex- tremely variable (Fig. 3). The high peak dis- charge on 16 May 1984 established a record flow for the 75 vears that records have been kept on Salmon Falls Creek (USDI 1985). Although apparently not a record low peak flow, the highest discharge in 1981 (27-28 March) was just 1.9 times greater than the 72-year average discharge (in comparison, the 1983 peak was 26.4 times the average) (USDI 1982, 1985). Conversely, minimum flows were relatively stable throughout the period. Fish populations in Chimney Creek fluctu- ated over the period (Table 1) and were at their most depressed levels during the drought year of 1981 and the record runoff of 1984. Most of this difference was due to rela- tively weak YOY age classes (i.e., low YAR), particularly in 1981 when no YOY individuals were encountered (Fig. 4). In 1982, the YOY class exhibited its greatest strength, while the absolute number of adults was at its lowest point during the study. Of particular interest, however, is the split YOY class observed in 1983. Two distinct sub- populations (length-classes) of YOY individu- als collected in 1983 were separated by an average of approximately 20 mm. This sug- gests the occurrence of at least two spawning periods. Inspection of the hydrograph from 1983 in Figure 3 reveals one early peak runoff^ event in late February', followed about six weeks later by the beginning of the expected spring rimoff. The runoff^ pattern after mid- April in 1983 was similar to that of the same period in 1982, except that 1983 reached peak discharge about 1 June, much later than the early May peak of 1982. We do not know whether the first spawn occurred in response to the February peak or as flows began to recede after the initial peak in late April, fol- lowed by normal spawning after the true peak discharge in May. Inspection of the sizes of the fish relative to other years (Fig. 4), how- ever, suggests the latter alternative. Despite the fairly large fluctuations in pop- ulation size, biomass as a function of average stream volume fluctuated much less. Only 1983 showed an unusually large biomass be- cause of an exceptionally strong YOY age class. Average condition (Table 2) was also high during this period, particularly the alio- July 1987 Nelson etaL: Cutthroat Trout Behavioh 485 metric value. lu geueral, however, the iso- metric relationship provided higher estimates of robustness. In fact, allometric estimates were typically very low (assuming an opti- mum of 1.00), indicating disproportionately more growth in length than in mass. Examina- tion of the growth coefficient emphasizes this different growth performance in 1983, the only year in which average YOY isometric condition exceeded that of adults. Discussion Floods have long been considered destruc- tive events for trout populations. Seegrist and Card (1972) showed flooding to reduce brook trout production in California and indicated that the effect was most severe on adult trout. Similarly, Elwood and Waters (1969) demon- strated impaired brook trout production when flooding reduced invertebrate food supplies. Such results are to be expected for fish resid- ing in typically stable or predictable environ- ments. In fact, the beaver impoundments of- ten used by brook trout might be considered unusually stabilized habitats. It seems likely, however, that trout inhabiting frequently and capriciously flooded environments would be less disturbed by flooding. Interestingly, 1981, the year with the most stable flows, yielded no YOY individuals in the population sample. Chimney Creek be- came intermittent in August 1981, and some studies (Lea 1968, Platts 1960) have suggested that downstream migration from natal gravels may occur shortly after emergence, possibly stimulated by receding flows (Benson 1960). The early attenuation of adequate flows may have prompted an early emigration. Coffin (1982), however, states that YOY Humboldt cutthroat remain in their natal stream at least until the following year's runoff period. Given the large adult population and the fact that YOY are normally present in mid-August, it seems more likely that one of two other factors was operating: (1) quality rearing habitat may have become limiting, or (2) adults in Mary's River could not ascend Chimney Creek be- cause low flows were insufficient to allow pas- sage over beaver dams near the confluence of Chimney Creek and Mary's River (Gene Weller, Regional Fisheries Supervisor, Ne- vada Department of Wildlife, Elko, Nevada, personal communication). In the former case. if rearing habitat were at a premium, YOY individuals would be forced into more fre- quent, fatal encounters with predatory adults; in short, they may have been heavily preyed upon in 1981. Van Deventer and Platts (in press) showed that YOY survival was quite high in a small stream in Yellowstone National Park from which adults emigrated immedi- ately after spawning, further suggesting that predation may have been a significant factor in Chimney Creek in 1981. Our results suggest that Humboldt cut- throat trout populations are not severely af- fected over the long term by even extreme flooding and that appropriate responses to ir- regular discharge events constitute part of their adaptive strategy. In fact, the somewhat reduced number of YOY in the 1984 sample may have resulted simply from early passive movement downstream and not any actual reduction in productivity. Johnson (1983) sug- gests that increased flows stimulated down- stream movement of Lahontan cutthroat trout in Cold Creek, California, but there is also the possibility that this could be interpreted as a passive downstream movement of YOY indi- viduals in response to periods of increased flow. We have also demonstrated one clear incidence of a split spawning period that pro- duced two distinct YOY subpopulations. We cannot determine precisely the triggering mechanism for this behavior but offer two alternative hypotheses. First is that the early discharge event in the first part of March ini- tiated an early spawning run. Second is that the undulating nature of the main portion of the discharge hydrograph (mid-April to mid- June) was perceived by spawners to be two distinct runoff events. Because of the parity in length of the principal 1983 YOY subpopula- tion with that of 1982, we consider the latter alternative more probable. Smith (1941) re- ported split runs of Yellowstone cutthroat (S. c. boiweri) in two tributaries of Yellowstone Lake, which he attributed to genetic differ- ences between two distinct subpopulations of spawners. We believe a similar mechanism may be at work in Chimney Creek. This could take the form of either two distinct subpopula- tions ascending from Mary s River at different times or out-of-phase spawning between mi- gratory and resident populations. There is lit- tle basis at this point for deciding which of these is more likely, and it is easy to imagine 486 Great Basin Naturalist Vol. 47, No. 3 migratory individuals in a river environment responding to watershed events differently than small tributary residents might. Migra- tory individuals would be responding to wa- tershed-wide (macro) events, whereas behav- ior of tributary residents would be triggered by local (micro) events. More sophisticated studies of spawning movement and behavior, and more localized discharge data are needed to better understand this apparently adaptive behavior. Whichever mechanism is responsible for promoting two subpopulations of spawners, the adaptive advantage is clear: sufficient ge- netic diversity is present to ensure successful reproduction during the most irregular of weather patterns. Judging by the very high average condition of both trout age groups in 1983, it seems also to confer the ability to exploit unusually favorable conditions (which must have occurred in 1983 to promote high population sizes and high robustness). That the trait may be a primitive one is corrobo- rated by its occurrence in the genetically dis- tant Yellowstone subspecies. Loudenslager and Gall (1980) have shown Lahontan cut- throat trout to be the most genetically diverse of the subspecies. In fact, splitting the Lahon- tan into Lahontan and Humboldt subspecies would produce two subspecies of unusually high genetic diversity, with the Humboldt strain apparently the more variable. This quite strongly suggests the value of maintain- ing a variable gene pool to promote environ- mental tolerance in a capricious environment. As cold-water fisheries in the interior west- ern United States continue to increase in value, and as the value of preserving biologi- cal diversity becomes more widely recog- nized, we hope that preliminary efforts such as this will stimulate further research into mechanisms of adaptation to apparently unfa- vorable habitat conditions. The fact that Humboldt cutthroat trout can persist and even prosper in water unsuitable to brook and rainbow trouts has already been demon- strated (Behnke 1979, Platts and Nelson 1983). Many interior watersheds in the west- ern United States are presently degraded from inappropriate land-use practices, and it seems clear that tolerant salmonids such as the Humboldt cutthroat could provide a valu- able resource for stocking into habitats gener- allv deemed unsuitable for trout. This could be an adjunct treatment for increasing the fishery resource of the degraded streams com- mon in overgrazed watersheds in the Inter- mountain and Great Basin areas. It should be considered only as an interim step while more permanent rehabilitation efforts aimed at restoring streams to their native potential are instituted. LiTER.\TURE Cited Bagenal, T B . AND F VV Tesch 1978. Age and growth. Pages 101-136 in T. Bagenal, ed., Methods for assessment offish production in fresh waters. IBP Handbook No. 3. Blackwell Scientific Publ., Ox- ford, United Kingdom. 365 pp. Behnke, R J 1979. Monograph ofthe native trouts of the genus Salmo of western North America. USD A For. Serv., Rocky Mountain Region. 163 pp. Benson, N G 1960. Factors influencing the production of immature cutthroat trout in Arnica Creek, Yel- lowstone Park. Trans. Amer. Fish. Soc. 89: 168-17,5. Coffin, P 1982. Lahontan cutthroat trout fishery man- agement plan for the Humboldt River drainage basin. Nevada Dept. Wildlife, Federal Aid Project F-20-17, Studv IX, Job No. 1-P-l. 33 pp. Elwood, J W , andT F W.\ters 1969, Eff'ects of floods on food consumption and production rates of a stream brook trout population. Trans. Amer. Fish. Soc. 98(2): 253-262. Erman, D C , AND V M H.WVTHORNE 1976. The quanti- tative importance of an intermittent stream in the spawning of rainbow trout. Trans. Amer. Fish. Soc. 105(6): 67.5-681, HOLLING. C S 1973. Resilience and stability of ecological systems. Aijnual Re\ iew of Ecologx' and Systemat- ics 4: 1-23. Johnson, G L. 1983. Juvenile Lahontan cutthroat trout Salmo clarki henshawi, emigration behavior and effects of resident salmonids upon cutthroat trout fry in two tributaries ofthe Truckee River in east- ern California. Unpublished thesis, Lhiiversity of Idaho, Moscow. Lea, R N 1968. Ecology ofthe Lahontan cutthroat trout, Salmo clarki henshawi, in Independence Lake, California. Unpublished thesis. University of Cah- fornia, Berkeley. Loudenslager, E. J . and G A. E Gall 1980. Geo- graphic patterns of protein variation and subspeci- ation in cutthroat trout, Salmo clarki. Systematic Zoology 29: 27-42. May, B E , J D Leppink, and R S VVydgskl 1977. Dis- tribution, systematics, and biology of the Bon- neville cutthroat trout. Page 26 in Utah State Div. Wildlife Resources, Publ. 78-15. Platts, W S 1960. Investigations of Strawberry Reser- voir tributaries. Utah State Dept. Fish and Game, Project No. F-4-R-4, Job No. P. 12 pp. Platfs, W S., K a Gebhardt, and W. L. Jackson 1985. The effects of large storm events on basin-range riparian stream habitats. Pages 30-34 in North American riparian conference, 16-18 April 1985, Tucson, Arizona. julv 1987 Nelson ETAL: Cutthroat Trout Bkhavior 487 Platts, W S , W F Megahan, and G VV. Minshall 1983. Methods for evaluating stream, riparian, and biotic conditions. USDA For. Serv., Gen. Tech. Rep. INT-138. 177 pp. Platts, W. S , and R. L Nelson 1983. Population fluctu- ations and generic differentiation in the Humboldt cutthroat trout of Gance Creek, Nevada. Trans. Cal-Neva Chap. Amer. Fish. Soc. 1983: 1.5-20. Pl.\tts,W S , R J ToRQUEMADA, andR. L. Nelson 198.5. Livestock-fishery interaction studies. Chimney Creek, Nevada, progress report 3. Lhipnblished report on file at USDA For. Serv., Intermountain Research Station, Forestry Sciences Laboratory, Boise, Idaho. Raleigh. R. F., and D A Duff. 1981. Trout stream habi- tat improvement: ecology and management. Pages 67-77 in W. King, ed.. Proceedings, wild trout symposium II, 24-25 September 1979, Yel- lowstone National Park, Wyoming. Seegrist, D. W.. and R. Card 1972. Effects of floods on trout in Sagehen Creek, California. Trans. Amer. Fish. Soc. 101(3): 478-482. SiGLER, W F . VV T Hel.m, P A Kucera, S. Vigg, and G VV Workman 1983. Life histor\- of the Lahontan cutthroat trout, Sahno clarki henshaici. in P\Ta- mid Lake, Nevada. Great Basin Nat. 43(1): 1-29. Smith. O. R. 1941. The spawning habits of cutthroat and eastern brook trouts. J. VVildl. Manage. 5(4): 461-471. Thod.u, J M 1959. Effects of disruptive selection. 1. Genetic flexibility. Heredity 13: 187-203. U.S. Departmentof THE Interior, Geological Survey. 1982a. Water resources data for Nevada. Water year 1981. Rep. NV-81-1. 1982b. Water resources data for Idaho. Water vear 1981. Rep. ID-81-1. 1983. Water resources data for Idaho. Water vear 1982. Rep. ID-82-1. 1984. Water resources data for Idaho. Water year 1983. Rep. ID-83-1. 1985a. Water resources data for Nevada. Water year 1984. Rep. NV-S.5-1. I98.5b. Water resources data tor Idaho. Water vear 1983. Rep. ID-84-1. Valentine. J, W. 1969. Niche diversity and niche size patterns in marine fossils. J. Paleontol. 43(4): 905-915. Van De\ enter, J S.. and VV S. PL.-\Trs. 1984. Sampling and estimating fish populations from streams. Trans. North Amer. wildlife and natural resources conference 48: 345-354. In press. The production and migration of Yellow- stone cutthroat trout in Hatchery Creek, Yellow- stone National Park. North Amer. J. Fish. Man- age. Wellington. VV G 1964. Qualitative changes in popula- tions in unstable environments. Canadian Ento- mologist 96: 163-213. NICHE PATTERN IN A GREAT BASIN RODENT FAUNA Edward H. Rohey, Jr.', H. Duane Smith', and Mark C. Belk' Abstract. — Niche pattern of a desert rodent communit>' in shrub habitats of central Utah was examined in the canonical space formed by the first four principal components of trapsite niicrohabitat. Positions of species centroids differed significantly (P < .05) in this space and were consistent with the known habits of each; thus, it appears that the principal components measured biologically meaningful facts. Abundance in optimal habitat (a,) increased with niche breadth (v,) and decreased with increasing difference of centroids of a species from the overall mean habitat (d,). v, was positively related to dj. Differences between niche pattern of this community and that of deciduous forest small mammals are discussed. Identification of mechanisms that prevent competitive exclusion has been the objective of many studies of rodent habitat. Habitat selection is reported to be a major mechanism allowing sympatric coexistence of cricetid ro- dents (Grant 1972, M'Gloskey and Fieldwick 1975, Dueser and Shugart 1978, Kitchings and Levy 1981, Van Home 1982, Parren and Capen 1985, Seagle 1985b). Heteromyid ro- dents reportedly partition foraging space on the basis of microhabitat (Lemen and Rosen- zweig 1978, Price 1978, M'Closkev 1980, Hal- lett 1982, Thompson 1982a, 1982b, Price and Brown 1983). Research into other aspects of community structure such as relationships be- tween abundance and niche parameters has recently received attention (Dueser and Shugart 1979, Anthony et al. 1981, Carnes and Slade 1982, Van Home and Ford 1982, Seagle 1985a, 1985b, Seagle and McCracken 1986), but an understanding of these complex interactions is lacking. The interrelationship between abundance, niche breadth, and niche position is called niche pattern (Shugart and Patten 1972). Niche pattern has not been studied in enough communities, nor long enough in any one community, to understand how individual components are related or how they vary with other factors such as community stability and productivity. In communities that have been studied (birds by Shugart and Patten 1972, eastern deciduous forest small mammals by Dueser and Shugart 1979, Seagle 1985b, Sea- gle and McCracken 1986), the most abundant species had the broadest niches and were clos- est to the mean habitat. To evaluate general relationships among abundance in optimal habitat, niche position, and niche breadth, and to identify factors that may influence these relationships (and thus affect community structure), it is necessary that a wide variety of communities be studied. The objectives of this paper are: (1) to describe the niche pattern of a rodent community in shrub habitats of the Great Basin Desert and (2) to compare the observed niche pattern with that reported for deciduous forest ro- dents (Dueser and Shugart 1979) in an at- tempt to identify factors related to differences in structure of these two communities. Study Area and Methods Study Area Shrub communities in the cold desert of central Utah were chosen in Juab and Tooele counties to provide a variety of vegetation and soil characteristics. Some sites were selected on vegetated sand dunes and others in adja- cent areas with finer-textured soils. Dominant shrubs on the sandy areas were greasewood (Sarcobatus vermiculatus) and rabbitbrush {Chnjsothamnus spp.), while sagebrush {Artemisia tridentata) was dominant on the finer-textured soils. Cheatgrass {Bromus tec- torum) was the most common herbaceous species, although ricegrass (Oryzopsis hy- menoides) was locally common on the dunes. The most frequently encountered forbs were Russian thistle (Salsola kali) and scurfpea {Psoralea tenuiflora) on predominantly sandy Department of Zoology. Brighani Young University, Prove, Utah 84602 488 July 198' ROBEYETAL.: RODENXNlCHE PATTERN 489 soils and Lepidiiim spp. and Dcscurania sp. on finer-textured soils. Trapping Small mammals were trapped with mu- seum special snap traps baited with oatmeal and placed 12-15 m apart in 4-10 parallel transects of 10-25 traps each. Transects were trapped for three consecutive nights. Traps were usually baited in the afternoon and re- mained set through each trapping period. Captured animals were removed from traps each morning and the capture site, species, sex, and age of each recorded. Microhabitat Variables Nine variables were used to characterize microhabitat at each trapsite. These variables included percent bare ground and litter, shrub, grass, annual, and total vegetative cover. Cover variables were visually esti- mated in a 1-m" circular plot centered on each trapsite. Distance from the trap to the nearest shrub and the height of that shrub were mea- sured. Soil texture was classified as either sand or fines (silt and clay). Bowers (1979) used similar variables to characterize habitats of desert rodents in Nevada. Analysis Symbolism for niche pattern parameters follows Dueser and Shugart (1979). d,, a mea- sure of niche position, represents the distance from the habitat mean to the centroid of spe- cies i. Niche breadth is symbolized by v,. The abundance of species i in its optimal micro- habitat is represented by a,. Parameters of niche pattern were estimated following a modification of the methods of Dueser and Shugart (1979). Dueser and Shugart used discriminant function analysis (DFA) to reduce intercorrelations among the original microhabitat variables and obtain a more parsimonious space in which to examine niches. We used principal component analy- sis (PCA) to achieve the same goal because: (1) the normalized eigenvectors provide an or- thogonal basis for the reduced space; and (2) the method requires no distributional as- sumption, whereas DFA requires the vari- ance/covariance matrices of all species to be equal, thus implying niches of the same size and shape. Because habitat variables were in different units (i.e., cm, %), a correlation ma- Table 1. Principal components of trapsite habitat. Normalized > eigenvectors Variable PCI PC2 PC3 PC4 Litter cover 0.1319 0.4783 0..3762 0.3222 Annual cover .48797 -.2532 -.0521 -.1255 Shrub cover .1130 .6223 -.0303 .0984 Grass cover .4484 -.3152 -.0560 .0494 Shrub height .0231 .2232 .4206 -.8156 Distance to shrub -.160 -.1911 .5937 .4347 Bare ground -.5087 -.1641 -.0658 -.0729 Substrate .0006 -.3186 ..5610 -.0796 Vegetative cover .5207 .0767 -.0570 -.0495 Eigenvalue 3.448 1.826 1.329 .920 % of variance 23 20 15 10 Cumulative % 38 58 73 83 trix was used instead of the variance/covari- ance matrix in calculation of the principal components. Relative positions and separation of cen- troids of a species in PC-space were examined to determine if the principal components measured biologically relevant facts. Capture and noncapture sites of each species were compared with univariate (ANOVA) and multivariate (MANOVA) analysis of variance to detect species that did not respond to the habitat variables and to determine the rele- vance of the PCA-generated variables. Be- cause many noncapture sites were probably within the habitat of each species, these tests should be conservative estimates of micro- habitat use. Equality of centroids of a species was tested with MANOVA. Test statistics with P < .05 were considered significant, d, was estimated as the Euclidean distance from the mean of species is capture sites to the mean of all microhabitats included in the anal- ysis. These microhabitats included all capture and noncapture trapsites that were measured. Including only capture sites forces the cen- troids of abimdant species toward the origin (Carnes and Slade 1982). When all trapsites are included, there is no a priori reason for species with high a, to have low d,. Niche breadth (v,) was estimated as the mean square distance from the capture points of species i to its centroid (Carnes and Slade 1982). This measure of breadth is indepen- dent of distance from origin and niche orienta- tion, while the coefficient of variation of Dueser and Shugart's d-bar is not. The product of the number captured (nj and (2ttct ")^ (Dueser and Shugart 1979) was used as an estimate of aj. Sigma-squared was 490 Great Basin Natur'VLIST Vol. 47, No. 3 Table 2. Means of principal components at capture and noncapture sites of each species. DO = D. ordii, parvus, PM = P. maniculatus , RM = R. megalotis, OL = O. leucogaster, AL = A. leucurus, EM = E. minin PP N PCI PC2 PC3 PC4 VVilk's Species Cap N loncap Cap N [oncap Cap N oncap Cap N oncap Lambda DO 40 -L12' -0.50 -0.34 -0.06 0.45'' 0.04 -0.06 0.06 0.9770^ PP 26 -.82 -..52 .43'' -.10 -.39'' .08 .09 .05 .9880 PM 107 -.94^ .46 .38^ -.16 .18 .04 -.1,5'' .09 .9.58r RM 18 -..33 .54 .es*" -.10 .18 .06 -.27 .06 .9880 OL 8 1.03 -..53 .35 -.08 .76 .05 -.04 .05 .9930 AL .5 -.61 -.53 .96'' -.09 .55 .05 .28 .05 .9920 EM 7 -.27 -.54 .51 -.08 -.37 .06 .06 .05 .9972 '?< .01. ''P< 05 estimated by v, (n,/(nj— 1)). The calculation of aj assumes that all species were censused equally and that n, is representative of the density of species i for all i (Dueser and Shugart 1979). Because this assumption is questionable for this study, a, should be treated as an approximate index of the height of the resource utilization curve. Relation- ships between a,, d,, and v, were examined both graphically and with multiple regres- sion. Results and Discussion Capture Results Three hundred eighty-five small mammals were captured during 3,364 trapnights on 17 study plots. Microhabitat was measured at 47% (725) of the 1,538 trapsites, which in- cluded 211 capture sites. These captures were composed primarily of Peromysciis manicula- tus (n 107, 51%), Dipodomijs ordii (n = 40, 19%), Perognathus parvus (n - 26, 12%), Reithrodontomys megalotis {n ^ 18, 9%)On{/- chomys leucogaster (n = 8, 4%), Eutamias minimus {n 7, 3%), And Aimnosper7nophilus leucurus (n ~ 5, 2%). Other species captured included Dipodomys niicrops, Micro- dipodops megacephalus, Perognathus formo- siis, Peromyscus truei, Lagurus curtatus, Mi- crotus montanus, and Sorex cinereus. Principal Components The first component (PCI) accounted for 38% of the "variation" in the data and was weighted positively on annual, grass, and total vegetative cover, and negatively on bare ground (Table 1). This component can be in- terpreted as herbaceous cover. The second component (PC2) was largely influenced by shrub and litter cover and accounted for 20% of the "variation. The third component (PC3) accounted for 15% of the "variation" and was strongly related to shrub height, distance to nearest shrub (a decreasing function of shrub density), and soil texture. This component increased as shrubs became taller and more sparse and soils became more sandy. Compo- nent 4 (PC4) represented a contrast between shrub height and distance to nearest shrub. This component increased with increasing sparseness of shrubs and decreasing shrub height and can be intei-preted as openness. Together, the first four components ac- counted for 83% of the variation in the original nine variables. Niche pattern was examined in the four-space determined by these compo- nents. Capture vs. Noncapture Sites The mean of Peromyscus maniculatus cap- ture sites was significantly less on PCI and PC4 and significantly greater on PC2 than the mean of noncapture sites (ANOVA, Table 2). Capture sites had taller shrubs, more shrub and litter cover, and less annual cover. Differ- ences were significant in MANOVA. Dipodomys ordii capture and noncapture sites differed significantly (MANOVA, Table 2). PCI was significantly less and PC3 signifi- cantly greater on capture sites. These differ- ences indicate D. ordii was captured more often in microhabitats with less annual and shrub cover, but with tall, low-density shrubs. Capture sites of Perognathus parvus were in areas of finer soil texture with denser shrubs, greater shrub and litter cover, and less annual cover than noncapture sites. Al- though capture sites were significantly July 1987 RoBEYETAL: Rodent Niche Pattern 491 t •AL ^'- RM (0 3 O a® EM (0 > ■So 0)0 o Q. pp •PM •OL •DO ♦Shrub Density PCS Height, Sand DO CM O Q. » .PM .QL •CO (fi PP AL •RM EM Fig. 1. Means ofprincipal components at capture sites of each species. Symbols: DO D. ordii, PP = P. parvus, PM P. manictilatus, RM = R. megalotis, OL ^ O. leucogaster, AL = A. leucurus. EM ^ £. minimus. 492 Great Basin Natufl\list Vol. 47, No. 3 1.25 Niche Breadth (v) Fig. 2. Relationship of niche position to niche breadth. Symbols are same as in Figure 1. greater on PC2 and significantly less on PC3 (ANOVA), the differences were not significant when PC1-PC4 were considered simulta- neously (MANOVA, P - .070). PC2 scores of capture sites of Reithrodonto- 7nys megalotis were significantly greater than those of noncapture sites. Capture sites of R. megalotis were characterized by high annual, shrub, and litter cover with tall shrubs. The difference between capture and noncapture sites was not significant in MANOVA (P = .069). Capture sites of Onychomys leucogaster, Ammospcrmophilus leucurus, and Eutamias minimus did not differ significantly from non- capture sites along PC1-PC4 (MANOVA). The lack of significance may be due to the low number of captures for each of these species. although for O. leucogaster it may be due to nomadic behavior and broad habitat affinities. Onychomys leucogaster and A. leucurus were captured more often on sandy soil with tall, relatively dense shrubs and less cover by an- nuals (Table 2). The high mean value of PC4 for A. leucurus is due to a very high litter cover. Capture sites of £. minimus had more annual cover and finer soil texture than non- capture sites. The high score on PC2 is due to high litter and not to shrub cover. Differences Among Species Means of species capture sites differed sig- nificantly along PC1-PC3 (MANOVA, Fig. 1). Species differed significantly along PC3. Capture sites of A. leucurus and P. parvus are low on PC3, indicating habitats with dense. July 1987 RoBEv ETAL: Rodent Niche Pattern 493 short shrubs aud fine soil textiue. The means of capture sites of D. ordii and O. Iciicogaster are on the high end of the PC3 scale. These species were captured most often on sandy soil with tall, sparse shrubs. The positions of E. Dunimus, O. Icuco^aster, and D. ordii are distinctly but not significantly separated along PC2. Capture sites of D. ordii had lower shrub and litter cover, while those of £. min- imus were high in these attributes. Differ- ences between species along PCI were not significant. Species not separated along PC2, however, have large differences along PCI. Both A. leucurusAwdR. megalotis were {onnd in greater herbaceous cover than P. parvus and P. maniculatus. Dipodomijs ordii utilized relatively open areas (Jorgensen and Hayward 1965, Rosen- zweig 1973, Schroder and Rosenzweig 1975, Brown and Lieberman 1973); however, P. parvus inhabited more closed, shrubby areas (Rosenzweig and Winakur 1969, Rosenzweig 1973, Nichols et al. 1975, Fautin 1946). Al- though found on nearly every grid, capture sites of P. maniculatus were closer than non- capture sites to tall shrubs. This agrees with results of Fautin (1946) and Rosenzweig and Winakur (1969). Location of R. megalotis cap- ture sites in dense vegetation near large shrubs also agrees with reports in the litera- ture for this species (Fautin 1946, Rosenzweig and Winakur 1969). Based on differences of means for a species in PC-space and consis- tency of habitat descriptions with published accounts for each species, it appears that the principal components represented habitat structure relevant to the habitat utilization of each species. Niche Pattern Niche breadth increases with distance from mean habitat (Fig. 2). Eutamias minimus, P. parvus, and D. ordii had the narrowest niches, while R. megalotis, O. leucogaster, and A. /eticun/.s had the broadest. Peromyscus maniculatus, P. parvus, and D. ordii were nearest the mean habitat, while O. leuco- gaster and A. leucurus were the most distant. Although the more numerous species had low d,, the less numerous species did not all have high d,. Abundance in optimal habitat de- creased with increasing dj, and, although not as clearly, abundance also decreased with in- creasing niche breadth (Figs. 3 and 4). Abun- dant species were close to the mean habitat and had narrower niche breadths. A regres- sion of a, on d, and v, showed a significant linear relationship (F - 8.06, d.f ~ 2.4). This differs from the pattern observed for deciduous forest small mammals (Dueser and Shugart 1979). In the deciduous forest com- munity, the more abundant species of small mammals were close to the mean habitat and had high niche breadths (a, increased with Vj and decreased with d,). Differences between results in Dueser and Shugart (1979) and this study may be partly due to different methods of calculating niche metrics. Since the niche metric calculations of Dueser and Shugart (1979) are not correct statisticallv (Carnes and Slade 1982, Van Home and Ford 1982), modi- fied methods proposed by Carnes and Slade (1982) were used in this study. However, dif- ferences in results may be due to real differ- ences in the two communities. Species diversity can influence niche breadth. In the desert shrub fauna we primar- ily worked with 7 species (14 total) as opposed to 4 species in Dueser and Shugart's (1979) deciduous forest. In addition to more species in the desert, the potential niche space may be less since forests are structurally more complex. Microhabitat niches of desert ro- dents must be narrower or overlap more than those of forest small mammals. In light of extensive literature on habitat partitioning in desert rodents (Bowers 1979, Holbrook 1979, Price 1978, Wondolleck 1978, Rosenzweig 1973, Thompson 1982a, 1982b, Hallett 1982, Price and Brown 1983, Lemen and Rosen- zweig 1978, etc.), higher overlap is improba- ble, and we suggest narrower niche width as the most likely situation. Frequency of occurrence or availability of a habitat in a given area decreases with increas- ing difference from the mean habitat (Shugart and Patten 1972). A species whose habitat centroid is far from the overall mean may either remain in a small, infrequent habitat patch or move between patches. A popula- tion, on the other hand, requires a minimum size or, equivalently, a minimum area to maintain itself A species with high dj should be broad-niched because: (1) in the course of its daily movements an individual is likely to move through several small patches of differ- ent types (fine-grained generalist); or (2) each individual remains in a single habitat patch 494 Great Basin Naturalist Vol. 47, No. 3 O C D TJ C D < zu.uu - *PM 15.00- - 10.00- - DO 5.00- - • PP *RM 0.00- _> -h^5L_ •al 0.500 0.750 1.000 1.250 Niche Position (d) Fig. 3. Relationship of abundance to niche position. Symbols are same as in Figure 1. type, but, because distant (high dj) patch types are rare, different individuals are in dif- ferent patch types. There remains the possi- bility of a species specializing on one rare patch type (high d,, low v,). These species should be highly mobile and relatively rare. Species packing in common habitats and generalizing in rare habitats could explain the observed pattern of abundant, narrow-niched species with low d, and less abundant, broad- niched species with high dj; but another possi- ble factor is temporal stability in habitat struc- ture. In postburn or postdisturbance succession, the structure of desert shrub habi- tats is relatively more stable than that of forests. Clearly, a burn changes habitat struc- ture and faunal composition of both (Koz- lowski and Ahlgren 1974), but the forest is changed more drastically and also will show greater changes in 100 yr (even 15 yr). The relative stability of desert structure could al- low increased habitat specialization of domi- nant species (Ricklefs 1979). Our data fit Rosenzweig's (1974, Lemen and Rosenzweig 1978) theory of evolution of habitat selection. Rosenzweig theorized that if habitat patch types are not equally abun- dant, there exists the possibility for two suc- cessful coexisting phenotypes, the specialist from the abundant patch type, and the gener- alist who can best exploit the mixture of patch types. The more common species (high a^) of this study were in the more abundant habitats (low d,) and had relatively narrow niches, while low aj species were in less abundant habitats (high d,) and had broader niches. The July 1987 ROBEY ET AL. ; RODENT NiCHE PATTERN 495 O C o C D < zu.uu - PM 1 5.00 - - 10.00- - DO 5.00- - • PP RM 0.00- EM 1 H-5!-- -f-JL- Niche Breadth (v) Fig. 4. Relationship of abundance to niche hreadtli. Symbols are same as in Figure 1. species in the desert rodent community oi this study differed in microhabitat preferences. It appears that there are a few abundant micro- habitat "patch types, " each with its own spe- ciahst. The generahsts are using a wider vari- ety of patches, although the patch types used by each may differ. The differences in niche pattern of decidu- ous forest and desert small mammal commu- nities point to different factors influencing the community structure of each. Species diver- sity, stability and diversity of habitat struc- ture, and possibly many other factors influ- ence niche characteristics of species in each community, affecting in turn species even- ness, local distribution, and perhaps the na- ture of competitive interactions. More studies of various communities and a standardization of techniques are necessary for the concept of niche pattern to help identify these factors and elucidate the importance of each. Ac K N O W LE DC M E NTS This research was supported by a research grant from Associated Students of Brigham Young University and funds from the Depart- ment of Zoology, Brigham Young University. The critical reviews of Drs. C. D. Jorgensen, K. T. Harper, D. K. Shiozawa, and C. L. Pritchett are appreciated. LiTER.\TURE Cited Anthony. R G , L J Niles. andJ D. Spring 1981. Small mammal associations in forested and old-field habitats — a quantitative comparison. Ecology 62: 955-963. 496 Great Basin Naturalist Vol. 47, No. 3 Bowers. M A 1979. Coexistence in desert rodents: a multivariate analysis. Unpublished thesis, Brigham Young University, Provo, Utah. Brown, J H., andG A Lieberman. 197.3. Resource uti- lization and coexistence of seed-eating desert ro- dents on sand dune habitats. Ecologv .54; 788-797. Carnes. B. A, andN. A. Slade 1982. Some comments on niche analysis in canonical space. Ecologv 6.3: 888-893. DUESER, R. D., AND H H Shugart 1978. Microhabitats in a forest-floor small mammal fauna. Ecologv .59: 89-98. 1979. Niche pattern in a forest-floor small mammal fauna. Ecology 60: 108-118. Fautin, R. W, 1946, Biotic communities of the northern desert shrub biome in western Utah. Ecol. Monogr. 16: 2.51-310. Grant, P R 1972. Interspecific competition among ro- dents. Ann. Rev. of Ecol. and Syst. 3: 79-106. Hallett, L G. 1982. Habitat selection and the commu- nity matrix of a desert small-mammal fauna. Ecol- ogy 63: 1400-1410. HOLBROOK, S J, 1979, Habitat utilization, competitive interactions, and coexistence of three cricetine rodents in east central Arizona, Ecologv 60: 758-769, Jorgensen.C, D, andC L Hayward 1965, Mammals of the Nevada Test Site. Brigham Young University Sci. Bull, Biol. Ser.6(,3): 1-81. Kitchings.J T .-vndD T. Levy. 1981. Habitat patterns in a small mammal communitv. J. Mammal. 62: 814-820. KozLOWSKi, T, T,, and C. E Ahlgren 1974. Fire and ecosystems. Academic Press, New York. Larsen. W, a,, and S J McCleary. 1972. The use of partial residual plots in regression analysis. Tech- nometrics 14: 781-790. Lemen, C. a,, and M. L. Rosenzweig 1978, Microhabitat selection in two species of heteromvid rodents, Oecologia 33: 127-135. M Closkey. R T 1980, Spatial patterns in sizes of seeds collected by four species of heteromyid rodents. Ecology 61:' 486-489, MCloskey, R T , AND B FiELDWiCK 1975. Ecological separation of sympatric rodents (Peromvscus and Microtus). J. Mammal. .56: 119-129. Nichols. D W , H D Smith, and M F Baker. 1975, Rodent populations, biomass, and community re- lationships in At-tcmisia tridentiita. Rush Valley, Utah. Great Basin Nat. .35: 191-202. Parren, S G., and D. E. Capen 1985. Local distribution and coexistence of two species of Peromtjsciis in Vermont, J, Mammal, 66: .36-44, Price, M. V. 1978. The role of microhabitat in structuring desert rodent communities. Ecology 59: 910-921. Price, M V , and J H Brown 1983, Patterns of morphol- ogy and resource use in North American desert rodent communities. Great Basin Nat, Mem, 7: 117-1,34, RiCKLEFS, R E 1979. Ecologv. 2d ed. Chiron Press, New York. Rosenzweig, M L 1973. Habitat selection experiments with a pair of coexisting heteromyid rodent spe- cies. Ecology .54: 111-117. 1974. On the evolution of habitat selection. Pages 401-404 in Proceedings of the International Con- gress of Ecological Structure, Functions, and Management of Ecosystems. Centre of Agricul- tural Publication and Documentation, Wagini- nen, Netherlands. Rosenzweig, M, L., and J Winakur 1969, Population ecology of desert rodent communities: habitats and environmental complexity. Ecology 50: .568-572. Seagle, S. W. 1985a. Patterns of small mammal micro- habitat utilization in cedar glade and deciduous forest habitats. J. Mammal. 66: 22-35. 1985b. Competition and coexistence of small mammals in an east Tennessee pine plantation. Amer. Midi. Nat, 114:272-282. Seagle, S W . and G F. McCracken 1986, Species abundance, niche position, and niche breadth for five terrestrial animal assemblages. Ecology 67: 816-818. Shroder, G E , AND M L Rosenzweig 1975. Perturba- tion analysis of competition and overlap in habitat utilization between Dipodoimjs ordii and Dipodomys merriami. Oecologia 19: 9-28. Shugart. H H , and B C P,\tten 1972. Niche quantifi- cation and the concept of niche pattern. Pages 284-327 1/1 B. C. Patten, ed.. Systems analysis and simulation in ecology. Vol. II. Academic Press, New York. Thompson, S D. 1982a. Microhabitat utilization and for- aging behavior of bipedal and quadrupedal het- eromyid rodents. Ecology 63; 1303-1312. 1982b. Structure and species composition of desert heteromyid rodent species assemblages: effects of a simple habitat manipulation. Ecology 63: 1313-1321. Van Horne, B. 1982. Niches of adult and juvenile deer mice {Peroinysctis manicidatii.s) in serai stages of coniferous forest. Ecology 63: 992-1003. Van Horne, B . and R. G. Ford. 1982. Niche breadth calculation based on discriminant analysis. Ecol- ogy 63: 1172-1174. Wondolleck. J T 1978. Forage area separation and overlap in heteromyid rodents. J. Mammal. 58: 510-518. PLANTING DEPTH OF HOBBLE CREEK' MOUNTAIN BIG SAGEBRUSH SEED Trac\ L. C. Jacobson' and Bruce L. Welch' Abstract — We conducted a greenhouse study in which Hobble Creek mountain big sagebrush {Artemisia tridentata ssp. vaseyana ) seeds were planted at various depths in soil to determine the optimal planting depth. Results showed that the optimal planting depth is 5 mm or less. Big sagebrush {At'tcmisia tridentata) is an important winter forage for wintering mule deer {Odocoileus hemionus Jiemionus) in the Rocky Mountains. In some areas big sage- brush is the single most important mule deer winter forage (Smith 1950, Leach 1956, Kufeld et al. 1973). This is due to big sage- brush abundance, availability, and superior winter nutrient content (Welch 1983). Recent reports have shown significant variation among subspecies and accessions within sub- species for production, preference, and win- ter nutrient content (Scholl et al. 1977, McArthur et al. 1979, Sheehy and Winward 1981, Welch and Pederson 1981, Welch et al. 1986, Personius et al. 1987, Wambolt et al. 1987). Of the accessions tested, an accession of subspecies vaseyana called Hobble Creek was found to be the most preferred accession by wintering mule deer and among the most preferred accessions by wintering domestic sheep {Ovis aries) (Welch et al. 1986). A. Perry Plummer discovered it in 1968 at the mouth of Hobble Creek drainage just east of Springville, Utah. 'Hobble Creek is a low- elevation mountain big sagebrush whose for- age value exceeds most winter forages for crude protein, phosphorus, carotene, and di- gestibility (Welch et al. 1986) and does not contain substances that lower grass cell wall digestion in ruminant animals (Hobbs et al. 1986). 'Hobble Creek' is needed to increase the nutrient content of winter diets of mule deer and domestic sheep. 'Hobble Creek' can be established by direct seeding, by transplanting bareroot or con- tainerized stock, and by a techni(}ue called "mother plant" (Welch et al. 1986). Direct seeding is the most practical method for establishing this superior accession of big sagebrush. Factors that affect germination and establishment include light, tempera- ture, available moisture, seed quality, seedbed preparation, seeding mixture, com- petition reduction, planting time, and plant- ing depth (Goodwin 1956, Payne 1957, Wel- don et al. 1959, Deitschman 1974, McDonough and Harness 1974, Harvey 1981). The last factor, planting depth, is the subject of this study. This study was designed to determine the optimal planting depth for seedling emergence and the effects of stratifi- cation on emergence. Materials and Methods The planting depths evaluated in this study were surface, 2 mm, 5 mm, 10 mm, and 15 mm. The depths were compared by planting unstratified seeds and stratified seeds. Petri dishes were also sown with seeds to check seed viability. Seeds were collected in November from a breeder plot in Hobble Creek Canyon east of Springville, Utah. Entire inflorescences were clipped, bagged, and air dried at room tem- perature for two weeks. Large stems were separated from the seed and chaff by hand stripping. After stripping, the seed and chaff were passed through a series of screens that removed the fine stems and larger particles of chaflF. The seed was cleaned to 70% purity with an air flow seed cleaner. At the time of use, a dissecting scope and tweezers were used to remove abnormal seeds and remain- ing chaff. The unstratified seeds were sealed USDA Forest Ser\ice, Intt-rmountain Research Station. Shrub Sciences Laborator\ . 73.5 North .500 East. Hrovo, Utah 84601. 497 498 Great Basin Naturalist Vol. 47, No. 3 in glass vials and stored at room temperature. The seeds to be stratified were treated with a fungicide (1 gram fungicide to 1 liter distilled water), sown in 9-cm sterile petri dishes con- taining distilled water-saturated no. 4 What- man filter pads", and then placed in a cooled room (2 C) for 10 days (Deitschman 1974). The experimental design consisted of 12 treatments (stratified + unstratified and con- trol + 5 planting depths) with 5 replications. Sixty containers were randomly arranged on a greenhouse bench. Ten of the 60 containers were sterile 9-cm petri dishes (controls), and 50 were 6-inch-deep by 2-inch-square pots. The petri dishes contained two layers of no. 4 Whatman filter papers. The square pots con- tained a sterile sandy loam that had been wa- tered and compacted to the desired depth before the seeds were sown. Soil was placed over the seeds in such a manner to maintain the desired depth and to eliminate com- paction. Fifteen 'Hobble Creek' big sage- brush seeds were sown in each container. Each of the six treatments was run on strati- fied and unstratified seeds (control, petri dishes, surface, 2 mm, 5 mm, 10 mm, and 15 mm). Seedlings were grown for five weeks. Day length was extended to 12 hours with the use of fluorescent lighting. Temperature was maintained between 15 and 10 C both day and night. Pots were checked daily for germinated seeds, and twice a day pots were watered with distilled water, using a squeeze bottle to avoid disturbing the soil surface. Germination or emergence was classified as complete with the appearance of green-colored cotelydons. T- tests were used to detect significant differ- ences between stratified and unstratified seed for the various planting depths. Analysis of variance was used to determine significant differences among the planting depths (Ryan et al. 1976). Results and Discussion Results of this study are given in Tables 1 and 2. Stratification treatment stimulated sig- nificantly (5% level) the rate and number of seeds emerged (Table 1). Stratified seeds Table L Comparisons between stratified and unstrati- fied seeds of Hobljle Creek' mountain big sagebrush {Artemisia tridentata ssp. vaseijana) planted at various depths. Comparisons were made with unpaired t-test. Data are expressed as numbers of seeds germinating out of a possible 75 seeds. Seed treatment Depth Stratified Unstratified T-values Seeds germinated out of 75 Petri dishes (control) 63 69 L897 Surface 48 35 2.982* 2 mm 49 27 2.678* .5 mm 45 33 3.539* 10 mm 0 9 3.087* L5 mm 0 2 1.000 ♦Significantly difTer ent at t - 0.05, 5d.f. - 2.015. The use of trade or firm names in this publication is lor reader information and does not imply endorsement by the U.S. Department of Agriculture of any product or service. started emerging three days after planting, while unstratified seeds did not emerge until seven days after planting. Stratified seeds had a significantly higher number of seeds emerg- ing for surface, 2-mm, and 5-mm depth than unstratified seed. Stratification had no signifi- cant effect on the number of seed emerging for control (petri dishes) and at the 15-mm depth. Unstratified seed had significantly more seeds emerge at the 10-mm depth than stratified seed. This last observation could be an artifact of the experiment. Because big sagebrush seeds are released in the late fall or early winter period, these seeds lay on or near the soil surface. During this period and into the spring, the seeds are usually in a moist- cold environment. We believe that the strati- fied seeds of this study are behaving more like those in nature than the unstratified seeds. Because of the significant effects of stratifi- cation, the data collected from stratified and unstratified seeds were not pooled for the analysis of variance. Analysis of variance did detect significant difference for numbers of seeds emerging at the various depths (Table 2). Controls (petri dishes), both stratified and unstratified, produced significantly (P " .05) more seedlings than all five depths. Surface, 2-mm, and 5-mm depths of both stratified and unstratified seeds produced signihcantly more seedlings than 10-mm or 15-mm depths. The probable higher temperatures and rel- ative humidity in the petri dishes may be the reasons that more seedlings were produced in the dishes, compared with the number pro- duced on the surface. We therefore conclude that 'Hobble Creek' mountain big sagebrush July 1987 JaCOBSON, WELCH: BiG SAGEBRUSH 499 Table 2. Optimal planting depth oi Hohhle Creek mountain big sagebrush (Artemisia tridentafa ssp. vaseyana) stratified and unstratified seeds. Data are ex- pressed as a mean and standard deviation per depth for five pots containing 15 seeds per pot. Seed treatment Stratified Unstratified Depth Seeds germinated Seeds germinated Petri dishes (control) 12. 6 ±1.02'' 13. 8 ±0.75^ Surface 9.6±1.50'' 7.0±0.89'' 2 mm 9.8±0.8l'' 5.4±3.0l'' 5 mm 9.0 ±0.89'' 6.6±1.10'' 10 mm 0.0±0.00'^^ 1.8 ±1.17' 15 mm 0.0 ±0.00' 0.4 ±0.80' Means sharing the same superscript within a seed treatment are not signifi- cantly different at the 5% level. should not be planted any deeper than 5 mm and that surface sowing onto disturbed soil is a practical seeding procedure for establishment of this accession (Kelsev 1986, Young and Evans 1986). Literature Cited Deitschman, G H 1974. Artemisia L. sagebrush. Seed of woody plants in the United States. USDA Forest Service, Agric. Handbook 450. Goodwin, D L 1956. Autoecological studies o{ Artemisia tridentata Nutt. Unpublished dissertation, Wash- ington State University, Pullman. Harvey. S J 1981. Life history and reproductive strate- gies in Artemisia. Unpublished thesis, Montana State University, Bozeman. HoBBS, N T, B L Welch, andT E Remington 1986. Effect of big sagebrush on in vitro digestion of grass cell wall. Pages 186-189 (n E. D. McArthur and B. L. Welch, compilers. Proceedings — sym- posium on the biology of Artemisia and Chnjsothamnus. LISDA Forest Service, Gen. Tech. Rep. INT-200. Ogden, Utah. Kelsey, R G 1986. Emergence, seedling growth, and crude terpenoid concentrations in a sagebrush garden. Pages 358-365 in E. D. McArthur and B. L. Welch, compilers. Proceedings — s\mpo- sium on the biology of Artemisia and Chnjsotham- nus. USDA Forest Service, Gen. Tech. Rep. INT- 200. Ogden, Utah. KuFELD, R. C , O C Wallmo, and C Feddema 1973. Foods of the Rocky Mountain mule deer. USDA Forest Service, Res. Pap. RM-11. Leach. H R 1956. Food habits of the Great Basin deer herds of California. California Fish and Game 42: 243-308. McArthur, E D , A. C Blaler, A P Plummer, and R. Stevens. 1979. Characteristics and hybridiza- tion of important Intermountain shrubs. III. Sun- flower familv. USDA Forest Service, Res. Pap. INT-220. McDonough, W T., and R O Harniss 1974. Effects of temperature on germination in three subspecies of big sagebrush. J. Range Manage. 27: 204-205. Payne, G. F. 1957. Some germination studies oi Artemisia tridentata. Proceedings of the Montana Academy of Science 17: 41-42. Personius, T. L., C L. Wambolt, J R Stephens, and R. G. Kelsey. 1987. Crude terpenoid influence on mule deer preference for sagebrush. J. Range Manage. 40: 84-88. Ry.\n, T a , JR , B L Joiner, and B. F Ryan. 1976. Minitab-Student handbook. Duxbury Press, Boston, Massachusetts. ScHOLL. J. P . R G Kelsey, and F Shafizadeh 1977. Involvement of volatile compounds of Artemisia in browse preference by mule deer. Biochem. Sys- tematics and Ecology 5: 291-295. Sheehy, D. P . AND A H. WiNWARD 1981. Relative palatability of seven Artemisia taxa to mule deer and sheep. J. Range Manage. 34: 397-399. Snuth. a D 1950. Sagebrush as winter feed for mule deer. J. Wildlife Manage. 14: 285-289. Wambolt, C L , R G Kelsey, T L. Personius, K D. Striby, a. F. McNeal, and K. M Haustad. 1987. Preference and digestibility of three big sagebrush subspecies and black sagebrush as related to crude terpenoid chemistry. Pages 71-73 in F. D. Provenza, J. T. Flinders, and E. D. McArthur, compilers. Proceedings — symposium on plant- herbivore interactions. USDA Forest Service, Gen. Tech. Rep. INT-222. Ogden, Utah. Welch, B. L 1983. Big sagebrush: nutrition, selection, and controversy. Pages 21-33 in K. L. Johnson, ed.. Proceedings of the first Utah shrub ecology workshop. College of Natural Resources, Utah State University, Logan. Welch, B L , and J. C Pederson 1981. In vitro digesti- bility among accessions of big sagebrush by wild mule deer and its relationship to monoterpenoid content. J. Range Manage. 34: 497-500. Welch, B. L.. E. D. McArthur, D L Nelson. J C Pederson, .\nd J. N. D.wis 1986. "Hobble Creek — a superior selection of low-elevation mountain big sagebrush. USDA Forest Service, Res. Pap. INT-370. Weldon. L W , D W Bohmont. and H P Alley 1959. The interrelation of three environmental factors affecting germination of sagebrush seed. J. Range Manage. 12: 236-238. Young, J A , and R A E\.\ns 1986. Seedhng establish- ment of five sources of big sagebrush in reciprocal gardens. Pages 370-374 in E. D. McArthur and B. L. Welch, compilers. Proceedings — sympo- sium on the biology oi Artemisia and Chnjsotham- nus. USDA Forest Service, Gen. Tech. Rep. INT- 200. Ogden, Utali. ANNOTATED INVENTORY OF INVERTEBRATE POPULATIONS OF AN ALPINE LAKE AND STREAM CHAIN IN COLORADO' John H. Bushnell", Susan Q. Foster", and Bruce M. Wahle" Abstract — Benthic macroin vertebrates were collected during the ice-free season (1 July-20 October) over a five-year period from a chain ot alpine lakes and intervening streams in the Green Lakes Valley (3,347-3,615 m) in Boulder County, Colorado. A list oftaxawas developed for 19S1 and 1982, with taxonomic additions for 1983- 1985 and comments on community structure, seasonal and elevational changes in species abundance, and noteworthy occur- rences. A total of 111 taxa was collected, of which 84% occurred in streams, 58% being exclusively lotic. Dipterans composed 73-81% of total abundance in streams. The littoral benthic zone of lakes was predominantly trichopterans and dipterans, 44-60% and 24-39%, respectively. Numerically important organisms in various lakes and streams were chironomids, simuliids (particularly Metacnephia), oligochaetes, and the bivalve Pisidiutn casertanum. An isolated lake and its outlet stream, with unique characteristics, were the sole locations ol Gamnmrus lacustris (Amphipoda) and Glossiphonia complanata (Hiriidinea). Manipulated lowering t)f a lake along the main drainage exposed abundant and luxuriant colonies of the bryozoan Fredehcella sultana. This organism was found on 43% of all rocks sampled, a preponderance heretofore unknown for this, or any, ectoproct in alpine or arctic lakes. There are few studies of lake chains and their intervening streams for mountainous subalpine regions of the world, and, to our knowledge, there are no such studies for true alpine environments. A general review of rel- evant published information for Colorado, temperate and subarctic North America, and other continents is given bv Bushnell et al. (1982). We obtained information during an ex- tended study of the aquatic macroinverte- brates of an alpine drainage system in the Colorado Rocky Mountains. During the ice- free season, macroin vertebrates were col- lected from five of six small lakes, and their intervening streams, in the Green Lakes Val- ley on the eastern slope of the Continental Divide, Boulder County, Colorado. This paper is a taxonomic inventory for 1981 and 1982, with additional new data for later years (Chironomidae excluded). Annotations are given on seasonal changes in species abun- dance, elevational aspects of community structure and abundance, and noteworthy oc- currences. The only directly applicable information on the macroinvertebrates of the Green Lakes drainage is by Elgmork and Saether (1970) and Saether (1970), and it is solely for the streams. These publications discuss ta.xo- nomic identifications derived from stream col- lections made in July 1960. Other publica- tions providing information on a variety of environmental topics are those of Halfpenny (1982), Caine (1984), Bushnell et al. (1984), Bushnell and Butler (1984), Caine et al. (1983), Hoffman et al. (1985), Short et al. (1983), Toetz (1985), and Toetz and Windell (1984). Site Description: Green Lakes Drainage The glacially carved Green Lakes Valley is about 40° N latitude and has been closed to the public since 1927 by the City of Boulder because the drainage is a municipal water source (Windell and Foster 1982). The entire study area (Fig. 1) lies above timberline in a 5.46-km" drainage basin, of which 0.42 km" is occupied by the five Green Lakes (GLs 1-5) and Lake Albion (Caine 1982). GL 5, fed by a stream from the Arikaree Glacier, is the highest lake (3,615 m) and is confluent with GL 4 (3,554 m; Fig. 2) via a connecting stream. The streams were named according to the lake from which they emanate; e.g.. Stream 5 leaves GL 5 and flows into GL 4; Stream 2 leaves GL 2 and flows into Lake Albion. Lake Albion (3,347 m) is the lowest lake in the study area, and the greatest eleva- This research was supported by National Science Foundation Grants BSR-8514.329 and BSR-S012()95 to the Institute of .Arctic and .\lpine Research. Department of Environmental, Population and Organismic Biolog\'. University of Colorado, Boulder, Colorado 80309. 500 July 1987 BusHNELLETAL: Colorado Alpine Invertebrates 501 Fig. L The Green Lakes (GLs 1-5), Lake Albion, and intervening stream segments of North Boulder Creek (Ss 1-5) located in an alpine valley on the east slope of the continental divide, 42 km west of the cit\' of Boulder, Colorado. terfall near the outlet ol GL 4, from the base of which the main stream and small tributaries follow a more gradual decline to GL 3 (Fig. 3). The linear distance between the inlet of GL 5 and the outlet of Lake Albion is 5 km. Only GL 1 (3,426 m) is apart from the main flowage system. This lake has no inlet, but it has a subterranean seepage that surfaces as a small stream (Stream 1), ultimately draining into Lake Albion. GL 1 (Fig. 4) has an open, south-facing exposure with a steep talus slope to the north and less-steep rises to the east and west. The ma.\imum depths of the lakes are 8 m for GLs 1 and 5, 13 m for GL 4, 16 m for GLs 3 and 2, and 14 m for Lake Albion. The bottom composition of most littoral zones of lakes, and of streams, is a mixture variously dominated by one or more of the following: boulders, large to small stones, and sometimes patchy areas of coarse to fine sand and silt. The bot- tom of the central and deeper portions of the lakes is almost entirely silt-clay (McNeely 1983). The lower lakes had a longer ice-free season in all years. Lake Albion and GL 1 reached maximal temperatures of 13 and 14 Fig. 2. Photograph of Green Lake 4 taken from an C, respectively, in August and early Septem- aspect facing north in late August 1985. ber of 1981 and 1982. Lakes 4 and 5 never experienced maxima much above 9 C. Data tional descent between any pair of connecting published by Caine (1984) indicate that pH lakes is 104 m between GL 4 and GL 3. Most values of the flowage water were nearly always of this vertical decline occurs via a steep wa- between 6 and 7. 502 Great Basin Naturalist Vol. 47, No. 3 Fig. 3. Photograph of Green Lake 3 taken from an aspect facing west. Waterfall in background is part of Stream 4 below outlet from Lake 4, August 1985. Fig. 4. Photograph of Green Lake 1 taken from an aspect facing north in early October 1986. Green Lake I is the only lake separated from the main drainage and with a full southern exposure. Lake Albion, GL 2, and GL 3 support popu- lations of brook trout {Salvclinus fontinalis) (Nelson 1976, Windell, unpublished data). Green Lakes 1, 2, 3, and Lake Albion have been enhanced in volume by the construction of dams. Repair of these dams during the sum- mer of 1985 necessitated a lowering of water levels by opening conduits near the bottom of lake basins. Water levels returned to normal in 1986 except in GL 2 where barrier damage was greatest. Methods Benthic macroinvertebrates were collected between 1 July and 20 October 1981 at two- week (sometimes three-week) intervals, with later beginning dates in succeeding years. Specimens were collected from three prede- termined and regularly sampled lake sites (ex- cept GL 2) and at intervening stream sites. The benthos was sampled using a rock- picking technique in the lakes and the Surber- sampling method in the intervening streams. The rock-picking involved turning over ran- domly selected rocks within the range of the sampling site. Organisms on the rocks (some- times on finer bottom sediments) were then removed with fine forceps. All picking times were standardized to 15 minutes. In addition to rock-picking, vegetation samples were taken from several lakes and streams. As all of the lakes have a generally narrow littoral zone, rock-picked (or bottom-picked) samples were most often obtained up to 3 m (infre- quently as much as 6 m) from shore. Surber-sampling stations in the streams generally were located either close to the out- let of one lake or the inlet of the succeeding lake, but the station between Green Lakes 3 and 2 was situated approximately equidistant from each lake. Two 1-min samples were taken 1-3 m apart at each station. Because of their proximity, these two samples were com- bined to give numbers of organisms per 0.09 m". The net mesh was 1024 um. When sam- July 1987 BUSHNELL ET AL. : COLORADO ALPINE INVERTEBPUTES 503 pies were unusually dense or confounded with excessive amounts of entangling vegeta- tion, aliquots were taken. The sample was first poured into an enameled pan and agitated either manually or with a magnetic stirrer. Then an aliquot, the volume of which was determined by the nature of the sample, was taken. A total of three aliquots was used from each sample. Specimens were preserved in 70% ethanol prepared with 5% glycerine. If field samples were placed in 5% formalin, they were later changed to the alcohol- glycerine solution. Taxonomic Identification Identification of aquatic insects was done by us almost exclusively from the immature aquatic stages, with samples confirmed by the taxonomic specialists cited below in the Ac- knowledgments. A large body of literature was used for identification (Allen and Ed- munds 1962, Arnett 1960, Baumann et al. 1977, Beck 1976, Bode 1983, Brinkhurst and Cook 1966, Brinkhurst and Jamieson 1971, Dodson 1982, Edmunds et al. 1976, Elgmork and Saether 1970, Fiance 1977, Harmston 1963, Hiltunen and Klemm 1980, Klemm 1982, Lepneva 1966, Mason 1973, Merritt and Cummins 1984, Morihara and McCaf- fertv 1979, Oliver et al. 1978, Pennak 1978, Peterson 1970, Roback 1957, Saether 1970, 1975, 1976, 1977, Simpson and Bode 1980, Smith 1968, Soponis 1977, Steyskaland Knutson 1981, Stone 1981, Surdick 1981, Szczvtko and Stewart 1979, Usinger 1956, Ward 1985, Wig- gins 1977, Wilson and McGill 1982, Wu 1978). Results The 1981 and 1982 collecting seasons (July-October) of the current study produced a total of 111 taxa, 93 of which occurred in streams (Table 1). Stream samples obtained by Elgmork and Saether (1970) in the first two weeks of July 1960 included 71 taxa of benthic macroinvertebrates. Of the 111 taxa included in our study, 64 were exclusively lotic, 18 were restricted to lentic sites, and 29 were both lentic and lotic in occurrence. At any particular collecting site the Chironomidae accounted for 31-51% of taxa in streams and 22-67% in lakes during 1981. Many taxa (30%) of the Green Lakes Valley flowage sys- tem were represented by a single specimen. About half of these were dipterans, thus un- derscoring the contribution of these insects to community diversity. Species richness in the littoral-benthic zone of these lakes ranged from 9 to 19 taxa. Dredge samples from deeper water pre- simiably would raise these values by con- tributing additional chironomids, oligo- chaetes, and nematodes. Mean Shannon- Weiner species diversitv was 2. 15 ± 1.08 for all lakes sampled in 1981 and 1982. In lotic habitats, species richness ranged from 24 to 40 taxa, and mean species diversity was 2.33 ± 0.75. Species diversities of Green Lake 1 and Stream 1 were both higher than mean diversi- ties of all lakes and streams. While community composition changed with elevation, there was no trend in actual species number. Discussion Numerical abundance among supra- generic TAXA. — Distribution of organisms among major taxonomic groups remained comparatively stable over the 21 -year period between the 1960 collections and the present study. The benthos of streams and lakes of Green Lakes Valley was predominantly dipterans. The Diptera constituted 81% of total macroinvertebrate organisms in streams in 1960, and 79% and 73% in 1981 and 1982, respectively. Worms (Nematoda, Oligo- chaeta, Turbellaria, and Hirudinea), Ephem- eroptera, Plecoptera, Trichoptera, and other taxa (Coleoptera, Mollusca, and Crustacea) individuallv accounted for less than 10% of total abundance in 1960, 1981, and 1982, with the exception of worms in 1982, which consti- tuted 15% of lake and stream abundance. A similar preponderance of dipterans be- came evident when abundances of organisms for streams alone were compared. However, lake organisms were predominantly tri- chopterans (44-60% of total abundance) and dipterans (24-39%). Worms, Ephemer- optera, Plecoptera, and other organisms inde- pendently constituted less than 10% of organ- isms collected in both 1981 and 1982. Again, deep-water dredge samples from lakes would likely increase the proportions of the dipter- ans, oligochaetes, and nematodes. Therefore, the somewhat contrasting importance of dipterans in lakes and streams is explained, in 504 Great Basin Naturalist Vol. 47, No. 3 Table 1. Benthic organisms oflakes and streams in the Green Lakes Valley, Boulder County, Colorado, for 1960 and 1981-1982. (New occurrences for later years: *1983, **1984, ***1985). Organism Relative abundance (I960)' Present studv Location Present study Cnidaria Hydra sp. PLATiHELMlNTHES (Turbellaria) Polycelis coronata NEMATODASp. Bryozoa Phimatella sp. statoblast Plumatella repens Fredericella sultana HiRUDINEA Glossiphonia complanata Oligochaeta Anahjciis sp. Chaetogaster cf. Diastrophtis Mesenchytraeiis sp. Nais variabilis Tubificidae sp. Litmbricuhis variegatus Amphipoda Gammartis lacustris AC.ARINA Atractides sp. Atttrus fontinalis Lehertia atelodon Limnochaetes americana Sperchon coloradensis COLLEMBOLA Poditra aqtiatica Ephemeroptera Siphlonuridae Amelettts sp. Siphlomtrus sp. Baetidae Baetis bicatidatus Baetis intermedius Baetis rusticans Baetis tricaudatus Heptageniidae Cinygmida mimus Ephemereliidae Drunella coloradensis Plecoptera Nemouridae Nemotiridae sp. Malenka sp. Nemoura sp. Nemoura arctica Zapada cinctipes Zapada haysi Zapada oregonensis Leuctridae Paralettctra or Perlomyia sp. Capniidae Bolshecapnia, Capnia, Mesocapnia, or Utacapnia sp. 1 ab. ab. ab. ab. ab. ab. less ab. ab. less ab. less ab. less ab. ab. less ab. less ab. ab. ab. ;ab. less ab. ab. ab. less ab. rare ab.*** ab. ab. rare less ab. ab. rare** less ab.* rare less ab. ab. rare ab. ab. ab. ab. less ab. rare less ab. less ab. less ab. less ab. less ab. L(3,A), S(l) L(A,: 3,4,.5), 8(1,2,3,5) L(A). s(i,.5; 1 L(A) L(3) L(l) L(3), S(l) L(3), S(l,2, L(A), L(5) L(3) 4,5) L(l), S(l) 8(1) 8(1) L(3) L(A), 8(1) 8(5) L(3,4), 8(4,5) L(A), 8(5) S(l,2,3,4,.5) 8(5) L(3,4), 8(1,3,4) 8(2,3) S(l,4,.5) 8(2) 8(5) 8(1,2) 8(1) L(5) L(5) July 1987 BUSHNELLETAL.: COLORADO ALPINE INVERTEBRATES 505 Table 1 continued. Organism Relative abundance (I960)' Present study Location Present studv Perlodidae Cnhtis sp. Isogenus sp. Isoperla ftisca Isoperia quinqucpunctata Kogotus inodcsttis Megarcijs signata Skwala parallela (?) Stveltsa sp. Hemiptera Notonectidae Notonecta sp. Trichoptera Trichoptera spp., earl\ instars Rhyacophilidae Rhyacophila sp. Rhijacophihi acropcdes (e) Rhyacophila angcUta Rhyacophila hyalinata (e) Rhyacophila tucula Lepidostomatidae Apatania sp. Brachycentridae Brachycentrus sp. Limnephilidae Hesperophylax sp. Hesperophylax occideiitalis Hesperophylax oreades (c) Psychoglypha subhorealis Psychoronia costalis (c) Leptoceridae (adult) Lepidopter\ Pyralidae sp. COLEOPTERA Dytiscidae Agabus sp. Dytiscus sp. Hydrophilidae Helophoru.s sp. Staphylinidae Staphylinidae sp. Elmidae Heterolimnius corptilenttis Zaitzevia sp. Heteroceridae Heterocerus sp. Georhyssidae Georhyssiis sp. DiPTERA Sciaridae Sciaridae sp. A Sciaridae sp. B Lycoriella (Heviineiiriiia) sp. ab. ab. ab. ab. ab. less ab. less ab. less ab. ab. S(l,3) rare less ab. rare ab. rare ab. S(2) S(3) S(3) S(3) L(4) L(A), S(l, 2,3.4) rare L(l) ab. L(1,A), S(l) rare lessab.*** rare less ab. S(l,5) S(2,3) L(3), S(2,3) 5(1,2,3,4,5) ab. L(1,A), S(2) ab. L(l-5), S(l-4) less ab. ab. L(A,1) L(A,1,4,.5), S(4) rare 5(1) rare 5(1) rare rare L(l), 5(5) 5(1) less ab. 5(3) rare 5(2) rare less ab. 5(1) 5(1) rare 5(5) less ab. 5(4) 506 Great Basin Naturalist Vol. 47, No. 3 Table 1 continued. Organism Relative abundance (I960)' Present studv Location Present study Empididae Atalanta sp. ab. Clinocera (Hydromia) sp. — Tipulidae Antocha sp. — Dicranota sp. — Erioptera (triinicra)sp. — Limnophora torreyae (e) — Onnosia sp. — Tipula sp. — Culicidae Culicidae sp. — Aedes spp. — Aedes (Ochlerotatiis ) impi^er les< Simuliidae Metacnephia sp. near jeanae — Prosimulium (Prosimulium) hirtipes ab. Prosimulium (Prosimtdium) travisi ab. Prosiinulhim (Prosimulium) ursinum (d,4) ab. Prosimtdium (Prosimulium) sp. near/ro/uief — Prosimulium n. sp. (d) — Simulium hunteri — Ephydridae Phihjgria dehilis Cressionclla montana less ab. less ab. ab. less ab. less ab. less ab. less ab. rare less ab. dom. rare less ab. ab. ab. ab. Thaumaleidae Thaumaleidae sp. — less ab, Thaumalea sp. less ab. — Chironomidae Chironomidae spp., larval bodies — less ab. Chironomidae spp., pupae — less ab. Chironomtts anthracinus group less ab. — Cardiocladius sp. ab. less ab. Chaetocladius — less ab. Corijnoneura sp. less ab. — Corynoneura taris — less ab. Cricotopus sp. 9 — less ab. Cricotopus sp. B — rare Diamesa sp. A (4) ab. — Diamesa sp. B ab. — Diamesa sp. C ab. less ab. Diamesa sp. D ab. — Diamesa sp. E less ab. less ab. Diamesa sp. F ab. less ab. Diamesa sp. G ab. less ab. Diamesa (Pseudokiefferiella) sp. H(4) ab. — Diamesa (Pseudokiefferiella) sp. J less ab. — Diamesa latitarsis gr. — ab. Diplocladius sp. — less ab. Eukiefferiella sp. A less ab. — Eukiefferiella sp. (subtype bavarica) sp. B (a,4) ab. — Eukiefferiella sp. C less ab. — Eukiefferiella sp. D less ab. — Eukiefferiella (type longicalcar) sp. E (b) ab. — Eukiefferiella sp. F less ab. — Eukiefferiella (subtype minor) sp. G (b) ab. — Eukiefferiella sp. H less ab. — S(2,4,5) S(3) 8(1,2,3,4,5) S(l) L(l), S(5) S(l) S(5) L(5) S(2) S(4,5) S(4) S(4) S(4,5) S(4,5) L(A), S(l) S(4) L(3 or 4) L(4), 5(2,4,5) L(3,5,A), S(4,5) S(5) L(A) S(5) L(3) L(3) S(3,4) S(4,5) S(2,4,5) S(3,4) S(3,5) L(3) July 1987 BUSHNELL ET AL.: COLOFL\DO ALPINE INVERTEBRATES 507 Table 1 continued. Organism Relative abundance (I960)' Present study Location Present studv EuhicfferieUa coerulescens group — Eukiefferiella devonica group — FAikicfferiella gracei group, sp. 1 (b) — Eukiefferiella gracei group, sp. 2 (b) — Eukiefferiella rectans.ularis group. T\pe J ab. Glyptotendipes i Phytotcndipes ) lobiferus {?) — Heptagijia sp. ab. Heterotrissocladius hirtapex — Hydrobaenusfusistyhis — Metriocnetnus sp. .\ less ab. Metriocnemus sp. B cf. Epoiicladius sp. less ab. Microcricotopus sp. parvulus type less ab. Micropsectra sp. ab. Micropsectra sp. 1 — Micropsectra sp. 2 — Sanocladius(\anocladius} spiniplenus — Orthocladiinae spp. — Orthocladius sp. — Orthocladius i Eudactylocladius ' sp. \ less ab. Orthocladius i Eudactylocladius > sp. B ab. Orthocladius i Euorthocladius ' sp. ab. Orthocladius i Euorthocladius ' type III — Orthocladius i Orthocladius ohuinbratus — Panastia sp. 1 — Parakieffericlla sp. ab. Parametriocnemus graminicola — Paraphaenocladius sp. less ab. Phaenopsectra sp. — Procladius sp. — Psectrocladius sp. — Psectrocladius octomaculatus less ab. Pseudodiamesa pertinax ab. Rheocricotopus sp. atripes type less ab. Rheocricotopus sp. effusus type less ab. Synorthocladius sp. — Theinemannia cL gracilis less ab. Trichotanypus sp. — Tvetania batarica group (a) — MOLLUSCA Sphaeriidae Pisiditun sp. less ab. Pisiditun casertanum — Pisidiuni nitidum — Pisidium variable — ab. rare ab. less ab. dom. ab. rare dom. dom. rare rare less ab. rare less ab. ab. ab. rare less ab. rare less ab. less ab. less ab. less ab. ab. less ab. ab. rare* ab. ab. rare rare L(3), S(4,5) S(2) S(4,5) S(l,3,4) S(l,2,4,5) L(l), S(l) S(l) L(3), S(4,5) L(3,A), 5(1,3,4,5) US) S(2) L(A), S(5) S(2) S(4) L(3), S(l,2,4,5) L(3,4), 8(1,3,4,5) S(2) 5(2,3,5) 5(1) 5(2,3) L(3,5), 5(5) 5(1) L(3,A) L(4,A), 5(5) 5(2) L(3), 5(4,5) L(5) L(3), 5(1) 5(1.4) 5(1,4) 5(1) 'Elgmork and Saether (1970) Collections from 1960: ab. ^ 38 most abundant ta.\a based upon mdi\ iduals sampled per 10-minute inters al; less ab. = all other ta.\a. "Present study: rare = Llessab. ^ 2-19; ab. = 20-299; dom. ^ >300 organisms collected during field season. ■'Distribution data are given for present study only: S = stream (1,2,3,4,5); L ^ lake (.'\. 1.2, 3,4, 5). See Fig. 1. Found b\ Elgmork and Saether (1970) outside of present study area. 'Eukiefferiella isubtvpe bavarica) sp. B (Elgmork and Saether 1970) is equivalent to Tt:etama bai:anca group in present study iPeterson 1983, personal communication'. ^Eukiefferiella (subtype minor) (type longicalcar) sp. E + G (Elgmork and Saether 1970) are equivalent to £. gracei group in present study (Peterson 1985, personal communication). '^Hesperophylax oreades (Elgmork and Saether 1970) is equivalent to Psychoronia costalis in present study (Wiggins 1983, personal communication). '^Prosimulium i Prosimulium ) ursinum (1970) is equivalent to Prosimulium n. sp. in present study (Peterson 1983, personal communication). "^Species designation tentative. part, by the restriction of lake sampling to the narrow littoral zone. Numerical abund.\nce among species. — The most abundant organism in 1981, the sim- uliid. Mctacnephia sp. near jeanae, com- prised 35.5% of all organisms collected. The absence ofMetacnephia in 1960 may be due to the earl\ sampling time in that year. Peak 508 Great Basin Naturalist Vol. 47, No. 3 abundance in 1981 and 1982 was in late July and again in early September. In 1985 it was during August. The most abundant stream species in 1960, the chironomid Eukiefferiella sp. G, may have been present in 1981 and 1982 as E. gracei species 1 and 2. A new taxon, E. rectan- gtdaris, a species first found in 1981, was fourth in abundance and was distributed throughout the same range of streams as was Eukiefferiella sp. G 21 years earlier. Perhaps these latter two organisms are temporally sep- arated conspecifics. Simuliids generally were dominants in 1960, 1981-1982, and 1985. Prosimulium hir- tipes and P. travisi together formed the sec- ond most abundant group in 1960. Their dom- inance was replaced in 1981-1982 by Prosimulium (Prosimulium) nea.r frohnei and Prosimulium n. sp. B., both of which were abundant. Prosimulium was concentrated in both studies in Streams 4 and 5, and also below Lake Albion in 1960 (outside the present study area). The recent manipulations of water levels in the lower lakes appear to have greatly reduced Prosimulium in Streams 3, 2, and 1.' Subdominants in 1960 included the chi- ronomid Diamesa sp. A. in streams above Lake 5 (outside present study area), oligochaete Mesenchytraeus sp. extending down into Stream 5, the chironomid Cardio- cladius sp., and Eukiefferiella sp. J., ranging throughout Streams 4 and 5. In 1981, sub- dominants were chironomids Hydrobaenus fusistylus in lentic and lotic situations above Stream 3; Micropsectra sp. 1, distributed throughout the study area; and the bivalve Pisidium casertanum, restricted to Streams 1 and4(GL3, 1985). Elevational distribution. — Elevational trends were apparent for several major taxo- nomic groups in lakes, but not in streams. Ephemeroptera and Trichoptera were more abundant in upper lakes (GLs 5 and 4) than in lower ones (Lake Albion and GL 1). These groups consisted mainly of shredders and scrapers. Dipterans were most abundant in lower lakes where rocks in the littoral zone were more often coated with a thin film of fine sediment and micro-Aufwuchs. Several taxa showed elevational range affinities in both 1981 and 1982. The blackfly Metacnephia (a filter-feeder) was especially numerous in Stream 5 (just below the GL 5 outlet) and extended in small numbers down to Stream 3. It is possible that GL 5 serves as a catchment for coarse and fine particulate organic matter derived from extensive Kobresia-a.\p\ne avens wetlands in the sur- rounding alpine basin. Studies of suspended particulate organic matter in the waters of Green Lakes Valley are not yet completed but possibly will have a bearing on this con- tention. Little is known about the physiology or aerodynamic suitability of the adults of this genus that may contribute to its successful breeding in this harsh environment. Baetis hicaudatus (an ephemeropteran collector-gatherer) and Hesperophylax (a tri- chopteran shredder) were distributed throughout the watershed in both years, but they were particularly abundant during the summer of 1982 in Stream 5. This may be attributable to an especially long growing sea- son on the high tundra in 1981, resulting in large allochthonous detrital food reserves in the stream the following year. Ephemeropterans are microhabitat special- ists sensitive to subtle differences in stream substrates and water velocities (Edmunds et al. 1976). The abundance oiCinygmula miiuus (a scraper) in Stream 4, Drunella coloradensis (an engulfer and scraper) in Stream 3, and Ameletus (a scraper) in upper streams and lakes (i.e. , Ss 5 and 4, GLs 5 and 4) may be the result of such microhabitat partitioning. Ameletus and Cimjgmula are genera with usu- ally lotic species, but they are found in lentic habitats in Green Lakes Valley. However, hy- drological studies indicate that these lakes are constantly flushing systems and have currents in some locations throughout the summer months (Caine 1984). Uniqueness of Lake i. Stream i. — Green Lake 1 and its outlet. Stream 1, are isolated from the main flowage of North Boulder Creek and have certain unique characteris- tics. Tributaries of this spur on the main drainage carry higher solute loads than other tributaries in the valley (Hoffman et al. 1985). Green Lake 1 is also the only lower lake in the valley without a fish population. The am- phipod Gammarus lacustris and the leech Glossiphouia complanata were restricted to this lake and stream. A longer ice-free season because of shallowness and full southern ex- posure, higher solute values, and a lack offish July 1987 BusHNELLETAL: Colorado Alpine Invertebrates 509 predators may contribute to the success of these species here. During a draw-down of GL 1 in the summer of 1985, G. hicustris mortahty was very high (estimates average 2/cm ) in evaporation pools at the receding lake edge. This species may well be the great- est producer of animal biomass in GL 1. Three species of fingernail clams (Sphaeri- idae: Pisidium casertanum, P. nitidiim, and P. variabilis) are sympatric in Stream 1. Pisid- ium cascftonutn was the fifth most abundant organism in the 1981 field season, abundant in Stream 1, and less so in Stream 4 (three dried specimens were found on the lake bottom of GL 3 in 1985 after the lowering of the water level). Pisidium variabilis was represented by only one specimen collected in Stream 1. The geographical distribution of most freshwater bivalves is limited by water chemistry, as more alkaline water with elevated calcium carbonate favors larger numbers of individu- als and species. However, Sphaeriidae con- struct shells in remarkably low concentrations of calcium carbonate (Pennak 1978). It is not uncommon to find Pisidium in alpine waters with very low dissolved solute concentrations, but its abundance in Stream 1 in 1981 and 1982 may reflect higher solute concentrations in this region of the Green Lakes Valley, con- sonant with a more efficient detrital trap (dic- tated by slow seepage into Stream 1 from GL 1). The three clam species can coexist in habi- tats only as low as pH 5.5-6.0 (Okland 1980, Okland and Kuiper 1980), which overlaps the lowest reading for Green Lakes flowage. In 1985 there was a notable decline of the Pisidium population in Stream 1. The lowered water level in GL 1 reduced the flow in Stream 1 to a trickle. This stressful condition and a pH near the known lower tolerance level for Pisidium species are probably impor- tant factors contributing to the decline. Bryozoa. — Only a single statoblast of an unidentified species of Plumatclla was found by Elgmork and Saether (1970). A colony of Phimatella repens with only five zooids was obtained from Lake Albion in 1982. However, the surprise during the 1985 season was the preponderance ofFredericella sultana on the rocks in Green Lake 3. The water level in this lake was lowered approximately 6.4 ni for dam repair. This change in water level exposed a considerable, normally submerged, rocky benthic area. Inspection of several rocks found to have dry colonies of F. sultami sug- gested that we should take radial transects (from the former lake margin to the lowered water line). Easily dislodged small- to medium-sized rocks along seven transects were examined. Forty-three percent (91 of 212 rocks) had one or more dried F. sidtana colonies attached. Many of these colonies were large, i.e., > 75-100 zooids, a few up to several hundred. Subsequently, numerous luxuriant living colonies were observed on submerged rocks at the water line and deeper down. Large colonies grow away from a sur- face as easily seen, loose tufts. Fredericella sultana has been reported from high- elevation Swiss lakes by Forel (1884). Bush- nell (1966) found this species surviving and slowly growing under lake ice all winter in Michigan. In GL 3 no colonies were found above the 1.3-m depth; thus, the species was below the level of the winter ice thickness. Since this species does not produce floating statoblasts, the primary means of settling on near-surface substrates is via the sexually pro- duced larvae. If colonies had been seasonally established on such substrates in GL 3, freez- ing and ice abrasion likely obliterated them. The most striking aspect of the Green Lake 3 fauna is that the largely rocky benthic re- gions, to as far down as we have observed, are dominated by a bryozoan macroinvertebrate. Such dominance is not commonly encoun- tered in warmer eutrophic lakes and was hereto- fore unknown for a truly alpine or arctic lake. Acknowledgments We gratefully acknowledge the taxonomic assistance of Drs. R. Bode, U. Lanham, W. N. Mathis, B. V. Peterson, G. Wiggins, S.-K. Wu, D. R. Oliver, and O. Saether, and the laboratorv and field assistance of B. J. Hanev, C. Nowicki, M. Cohen, and M. Hoch. S. Q. Foster and B. M. Wahle were responsible for a majority of taxonomic diagnoses made in our own laboratory. Name changes are indicated by footnote in Table 1. Finally, we thank Dr. R. W. Pennak for his comments following a careful reading of this paper. This study was a subproject of a five-year multidisciplinary Long Term Ecological Re- search (LTER) Project funded by the Division of Environmental Biology of the National Sci- ence Foundation. 510 Great Basin Naturalist Vol. 47, No. 3 Literature Cited Allen. R K., and G F. Edmunds, Jr 1962. A revision of the genus Ephemerella (Ephemeroptera: Ephemerellidae). V. The suhgeniis Drunella in North America. Misc. Puhl. Entoniol. Soc. Amer. 3: 147-179. Arnett, R H 1960. The beetles of the United States. Cathohc University of America Press, Washing- ton, D. C. 1,112pp. Baumann, R., a. R. Gaufin, and R F Surdick 1977. The stoneflies (Plecoptera) of the Rocky Mountains. Amer. Ent. Soc. Mem. 31. ii + 208 pp. Beck, W M , Jr 1976. Biology of the larval chironomids. State of Florida Dept. Environ. Reg. 2; 1-58. Bode. R W 1983. Larvae of North American Eiikief- feriella and Tvetania (Diptera: Chironomidae). New York State Mus. Bull, 4.52. 40 pp. Brinkhurst. R O , AND D G C pes of BCNRA. Numbers in parentheses indicate number of species found only in that habitat. Habitats are shown in order from xeric to mesic. Xeric Mesic Habitats Taxa Sagebrush grassland Upland shrub Conifer forest Riparian Wetland Streams Headwater rivers Reservoir Total [Code*] 1 2 3 4 5 6 7 8 Fish 8(1) Amphibians 1(1) 1 4 4 Reptiles 5 5 5 4(1) 3(1) Birds 61(11) 32(2) 58(10) 98(38) 98(74) Mammals 31(3) 22 25 32(2) 15 Species totals 99(15) 59(2) 88(10) 156(38) 120(77) Total hectares 698.8 728.2 108.8 263.2 21.8 Proportion of area 38.8 40 6 14.4 1.2 * From Table 1 19(1) 9(1) 25(6) 20(1) 28 25(6) 5 9 210 46 1820.8 100 This was the habitat of the spadefoot toad, although it is not common in BCNRA. Horned and sagebrush lizards were found in these habitats. Bullsnakes, yellow-bellied rac- ers, and milksnakes were observed in sage- brush habitat. Upland shrub. — Few bird species nested in upland shrub habitats, and relative abun- dance of species appeared to be low. Mi.\ed species flocks of birds were commonly seen moving through upland shrub habitats in the late summer and fall. Pocket mice were cap- tured in a sagebrush-juniper area. An Ord's kangaroo rat was trapped in sandy soil in ju- niper and mountain mahogany. No amphibi- ans were found in these dry habitats. The eastern short-horned and northern sagebrush lizard were observed here, as were the bull- snake, racer, and prairie rattlesnake. Conifer forest. — Conifer forests had a va- riety of birds and mammals. Eleven species were found only in this habitat. In the more open forests of ponderosa and limber pine. Cooper's hawks and some flycatchers were observed. Associated with the understory vegetation were both green-tailed and rufous- sided towhees. Tiger salamanders were occa- sionally found on the forest floor. Vagrans shrews and montane voles were captured in the ponderosa pine and Douglas- fir forests, where tracks of mule deer and elk also were frequently found. Riparian. — Shrub and creek woodlands as well as floodplain cottonwood constituted ri- parian habitats of the BCNRA. These areas had a large number of species, considering their relatively small total area (14.4%). The riparian habitats had a comparatively high number of species (38) found only in that habi- tat. Many of the unique vertebrates there were birds. Eastern kingbirds, lazuli buntings, rufous-sided towhees, and lark sparrows nested there, while Brewer s black- birds and green-tailed towhees were ob- served once during spring migration. Many birds observed there were also found in plains cottonwood forests. Few species of mammals were trapped in these habitats, although one of two specimens of western harvest mice and the only western jumping mouse were captured in the mature stand of cotton woods. A long-tailed weasel was seen, and white-tailed deer were com- mon. Tiger salamanders, chorus frogs, and leopard frogs were found in creek woodlands and floodplain forests. These areas provided moisture necessary to sustain the amphibians. Creek woodlands had a number of the reptile species including the bullsnake, milksnake, gartersnake, and prairie rattlesnake. Wetlands. — Most nesting bird species were associated with palustrine wetlands that had either emergent vegetation or mud shores. Dabbling ducks were observed using wetlands as brood habitat. Both pied-billed grebes and American coots nested in emer- gent wetlands. Emergent vegetation was commonK' used by yellow-headed and red- winged blackbirds, marsh wrens, and com- mon yellowthroats. MacGillivray's warblers and song sparrows were common in the shrub willow near shore. Because of the many aquatic and water birds found in wetlands, these areas had the highest (77) number of unique species. Mammals trapped in the wetlands were 516 Great Basin Naturalist Vol. 47, No. 3 mostly deer mice, although a western harvest mouse was collected in a stand of cattails. Mink were observed in an emergent wetland south of the causeway. Chorum and leopard frogs, woodhouse's toad, and tiger salaman- ders were found in wetlands with several snakes and painted turtles. Streams. — Five species of fish were cap- tured by electrofishing in streams (Appendix). Fish were found in only 6 of 12 perennial streams: Black Canyon Creek, Big Bull Elk Creek, Dry Head Creek, Deadman Creek, Gypsum Creek, and Porcupine Creek. Only the four largest streams contained salmonids. Most fish were captured in riffles or in pools beneath overhanging boulders. Headwater rivers. — The fish species known to occur in the headwater rivers were quite varied and included at least 19 species. Many species were ephemeral residents of rivers, using them during the spawning sea- sons. A variety of nongame fishes resided in the headwater rivers during much of the year. They included the lake chub, sturgeon chub, flathead chub, longnose dace, river carp- sucker, longnose sucker, white sucker, short- head redhorse, and stonecat. The headwater rivers had low sport fishing value within BCNRA. Reservoir. — The reservoir in both Mon- tana and Wyoming supported a substantial sport fishery. Sport fish introductions into the reservoir have lead to at least 10 additional fish species. While centrarchids have been introduced, they were not a dominant family because of the limited littoral areas, relatively cold water, and fluctuations in water levels. The reservoir had the greatest diversity offish species (25) as a result of the diversity of habi- tat features encountered over its length. Six fish were found only in the reservoir. Twenty- seven species occurred in the reservoir or rivers entering the reservoir as observed by the Wyoming Game and Fish Department and the Montana Department of Fish, Wildlife and Parks, which routinely surveyed these waters (Appendix). Shifts in Species Richness Each habitat type provided features that attracted species. Both habitat structure and moisture, which are examined in the discus- sion, influenced species richness. The drier habitats had fewer species than the terrestrial moist habitats (Table 2). Structure, however, influenced the total species count. Conifer forests, for example, had more birds than did the sagebrush/grassland and upland shrub habitats. No amphibians or reptiles were found in forest communities. Birds were in much higher numbers in riparian and wetland habitats. Thus, the changes in total species numbers were seen more in birds than in any of the other vertebrate groups. Introduced Species As people have come to BCNRA, verte- brate species have been introduced into the region. No introduced amphibians, reptiles, or mammals were found, although wild horses were in the region at one time. Introduced birds were primarily game birds: ring-necked pheasant, chukar, grey partridge, and turkey. These species were in sagebrush grassland, with the turkey also using forest and riparian habitats. Starlings were common in wetlands, and house sparrows were common around buildings and bridges. Of the 28 species of fish known to occur in BCNRA, 10 have been introduced by fishery managers for the purpose of enhancing sport fish diversity. Several species have been stocked in the reservoir since its construction: rainbow trout, brown trout, lake trout, large- mouth bass, green sunfish, black crappie, white crappie, and yellow perch. Additional species introduced in the nineteenth century include the brook trout and common carp. Discussion The results of our study on BCNRA indi- cated the importance of two habitat features, moisture and structure. Moisture seemed to have an even more pronounced influence on vertebrate species in the arid region. Combining the riparian and wetland terres- trial habitat, we accounted for only 15.6% of the area. These areas, however, had the more diverse population of vertebrates of the BCNRA. Many of the migratory birds were observed there. Shorebirds and waterbirds, as well as colonial nesting birds, were only in marsh habitat. Creek woodlands, which ac- counted for only 0.5% of the area, had 30% of the nesting birds. The moist habitat contained 11 of the 46 species of mammals and 9 of the 19 reptiles and amphibians. July 1987 Anderson etal.: Bighorn Canyon Vertebrates 517 Others have shown the importance of moist habitats for vertebrate species. In southern Wyoming, Krueger and Anderson (1985) found that birds utihzed shrub willow com- munities in higher proportion than other habitats. They showed the importance of the combined riparian habitats in the midst of a conifer forest and sagebrush community. Each riparian habitat did not ha\e the full complement of all birds. Rather, each small riparian community acted as a component is- land with its species composition. In the east- ern deciduous forest, atmospheric moisture influenced the composite of the breeding bird community (Petit et al. 1985). Rain, moisture, and/or humidity influenced distribution and reproduction in amphibians and reptiles (Duvall etal. 1982). Some species of frogs must have moist skin in order to breathe. Tied to the distribution pattern were en- ergy flow and food. Moist areas were likely to have a higher productivity, therefore more food. The concentration of vertebrates in moist habitats meant that they added to the total distribution patterns attracting preda- tors. Habitat structure has been associated with the presence and diversity of birds and mam- mals (Shugart et al. 1974). Structure at BCNRA was seen in the coniferous forest from both vertical and horizontal perspectives. Overall, 23.8% of the species of birds ob- served, 30. 1% of the nesting birds, and 24.2% of mammals observed and trapped were in coniferous forests. These habitat types ac- counted for only 6% of the terrestrial habitats in the study area. Thus, structure of conifer forests appeared to provide habitat for many vertebrates. Unique aquatic habitats important to fish were the perennial streams that supported salmonids, wetland areas associated with the headwater areas, and gravel-cobble riffles in the headwater rivers. The coldwater streams may support, or could potentially support, native stream fishes such as cutthroat trout. The wetlands associated with headwater streams are probably important spawning and rearing areas for several species, such as the plains killifish, yellow perch, and the cen- trarchids. The riffle areas are probably spawn- ing sites for over half of the fish species found in the BCNRA. Maintenance of these habitat features will be critical to maintaining current fish species diversity. The unicjue islands of aquatic habitat and the forest structure associated with BCNRA provide the diversity of habitat that allows many species to survive there. Influence of people can be seen through the introduction of new species, primarily for sport hunting and fishing, and alteration of habitats that af- fect native species, primarily through water development and agriculture practices. Acknowledgments We appreciate the assistance of many indi- viduals on the project. We thank K. Diem for his interest and his help in obtaining funding. Special thanks to J. T. Peters for his help with the field work and logistical support, and his hospitality. W. Bennewies and R. Lake pro- vided logistical support. Those who aided in the field work included L. Clark, J. Jones, M. Earnhardt, L. Kinter, J. T. Patterson, and T. Peterson. L. Clark, P. Gordon, B. Harrison, G. Jones, R. Kent, R. Lake, R. Myers, L. Pechacek, J. T. Peters, L. Stahl, and'S. Yekel provided useful suggestions and observations about species within the BCNRA. D. Walker and G. Menkens confirmed identifications of small mammals, and M. Bogan identified sev- eral bats. Finally, M. Brandt and L. Sweanor prepared many of the small mammals and bats for the museum. The project was funded by the University of Wyoming-National Park Service Research Center. Literature Cited American Ornithologists' Union. 1983. Check-list of North American birds. Lawrence, Kansas. Baxter, G T . and J R Simon 1970. Wyoming fishes. Bull. No. 4. Wyoming Game and Fish Depart- ment, Cheyenne. Ba.\ter, G. T.. and M. D Stone 198.5. Amphibians and reptiles of Wyoming. Wyoming Game and Fish Department, Cheyenne. Campbell, H W , and S P. Christman. 1982. Field tech- niques for herpetofaunal community analysis. Pages 193-200 in N. J. Scott, ed., Herpetological communities. USDI, Fish and Wildlife Service, Wildlife Research Report 13. COWARDIN, L M , V. C.\RTER, F C GOLET, AND E. T, LaRoe 1979. Classifications of wetlands and deepwater habitats of the United States. USDI, Fish and Wildlife Service, FWS/OBS-79/31. Washington, D.C. 103 pp. 518 Great Basin Natur\list Vol. 47, No. 3 DuvALL. D , L J GuiLLETTE. andR E Jones 1982. Envi- ronmental control of reptilian reproductive cycles. Pages 201-223 in C. Cans, ed.. Biology of the Reptilia. Academic Press, New York. DuvALL, D , M B. King, and K J Gutzwiller. 1985. Behavioral ecology of the prairie rattlesnake. Na- tional Geographic Research 1; 80-111. Hall, E R 1981. The mammals of North America. John Wiley and Sons, New York. 2 vols. 1,181 pp. Krueger, H O.. and S H Anderson 1985. The use of cattle as a management tool for wildlife in shrub- willow riparian systems. Pages 300-.305 in Ripar- ian ecosystems and their management. USDA, Forest Service, Central Technical Report RM- 120. National Park Service 1981. Final general manage- ment plan, environmental impact statement, wilderness recommendation, development con- cept plan — Bighorn Canyon National Recreation Area/Montana-Wyoming. Denver Service Cen- ter, Denver, Colorado. Oakleaf, B . H Downing, B Raynes, and O K Scott 1982. Wyoming avian atlas. Wyoming Game and Fish Department, Cheyenne. 87 pp. Petit, D. R . K E Petit, and T C Grubb 1985. On atmospheric moisture as a fact or influencing dis- tribution of breeding birds on temperature ot de- ciduous forests. The Wilson Bulletin 97: 88-96. Shugart, H. H., R. D. Dueser, and S H Anderson 1974. Influence of hat)itat alteration on bird and small mammal populations. Pages 92-96 in Pro- ceedings, Timber Wildlife Management Sympo- sium. Missouri Academy of Science, Occasional Paper 3. Appendix Habitat association of vertebrates in the BCNRA (* indicates introduced species, ** indicates that species is hkely to occur in indicated habitat but not documented within survey). Species Habitat association (code from Table 1) Fish (scientific names according to Ba.\terand Simon [1970]) Mountain Whitefish, Proposopitim ivilliamsoui 7,8 Cutthroat Trout, Salmo clarhi 6 Rainbow Trout*, Salmo gairdneri 6,8 Brown Trout*, Salvelinus tnitta 6,8 Brook Trout*, Salvelinus fontinalis 6,7 Lake Trout*, Salvelinus navunjciish 8 Lake Chub, Couesius plumheus 6,7,8 Common Carp*, Cijprinus caprio 7,8 Sturgeon Chub, Hijhopsis gelida 7 Flathead Chub, Hijhopsis gracilis 6,7,8 Fathead Minnow, Pimephales promelas 7,8 Longnose Dace, Rhinichthijs cataractae 6,7,8 River Carpsucker, Carpoidcs carpio 7,8 Longnose Sucker, Catostomus catostomus 6,7,8 White Sucker, Catostomus commersoni 7,8 Mountain Sucker, Catostomus platyrhynchus 8 Shorthead Redhorse, Moxostonia macrolepidotum 7,8 Channel Catfish, Ictalurus punctutus 7,8 Stonecat, Noturusflavus 7,8 Burbot, Lota lota 7,8 Plains Killifish, Fundidus zehrinus 8 Largemouth Bass*, Micropterus salmoides 8 Green Sunfish*, Lepomis cijanellus 8 Black Crappie*. Pomoxis nigromaculatus 7,8 White Crappie*, Pomoxis annularis 8 Yellow Perch*, Perca flavescens 7,8 Sanger, Stizostedion canadense 7,8 Walle\e*, Stizostedion vitreum litreum 7,8 Amphibians (scientific names according to Baxterand Stone [1985]) Blotched Tiger Salamander, Amlnjstoma tigrinum 3.4,5 Plains Spadefoot Toad, Scaphiopus homhifrons 1 Boreal (Western) Toad**, Bufo horeas 5 Woodhouse s Toad, Bufo uoodhousei 4,5 Boreal Chorus Frog, Pseudacris triseriata 4,5 Northern Leopard Frog, Rana pipiens 4,5 Reptiles (scientific names according to Ba.xter and Stone [1985]) Common Snapping Turtle**, Chchjdra serpentina 4,5 Western Painted Tiutle, Chrijsemijs picta 5 Spiny Softshell Turtle, Trionijx spiniferus 5,7 Northern Sagebrush Lizard, Sceloporus graciosus 1,2,3 Eastern Short-horned Lizard. Phn/nosoma douglassi 1,2,3 Rubber Boa**, Charina bottae 4,5 Yellow-bellied Racer, Coluber constrictor 1,2 Bullsnake, Pituophis melanoleucus sayi 1,2,3,4 Pale Milksnake, Lampropeltis triangulum 1,3,4 Red-sided Gartersnake**, Thamnophis sirtalis 4 Wandering Gartersnake, Thamnophis elegans 4,5 Western Plains Gartersnake **, Thamnophis radix 4 Prairie Rattlesnake, Crotalus viridis 1,2,4 Birds (scientific names according to Check-list of North American Birds [1983]) Common Loon, Gavia immer 4,5 Red-throated Loon**. Gavia stellata 5 Western Grebe, Aechmopliorus occidentalis 5 Horned Grebe**, Podiceps auritus 5 Eared Grebe, Podiceps nigricollis 5 Pied-billed Grebe, Podilymbus podiceps 5 White Pelican, Pelecanus erijthrorhynchos 5 Double-crested Cormorant, Phalacrocorax auritus 5 Timdra Swan, Cygnus columbianus 5 Trumpeter Swan**, Cygnus buccinator 5 Canada Goose, Branta canadensis 5 White-fronted Goose**. Anser albifrons 5 Snow Goose, Chen caerulescens 5 Mallard, Anas platyrhynchos 5 Black Duck**, Anas rubripes 5 Pintail, A »ifl.s«r(/frt 5 July 1987 Anderson etal.; Bighorn Canyon Vertebrates 519 Cadwall, Anas strepera American Wigeon**, Anas americana Eurasian Wigeon, Anas penelope Nortliern Shoveler, Anas clijpcata Blue-winged Teal, Anas discors Cinnamon Teal, Anas cyanoptera Green-winged Teal, Ar^as crecca Wood Duck, Aix sponsa Redhead, Aijtlnja americana Can\asback, Aijthya valisincria Ring-necked Duck, Aythya collaris Greater Scaup, Aythya marila Lesser Scaup, Aythya affinis Common Goldeneye, Buccphala clan- Egret, F.gretta thula Cattle Egret*, Bubulcus ibis Great Blue Heron, Ardea herodias Black-crowned Night Heron, Nycticorax nycticorax American Bittern, Botaiirus lentiginosus White-faced Ibis, Plegadis chihi Sandhill Crane, Grus canadensis Virginia Rail, Rallus limicola Sora, Porzana Carolina Yellow Rail**, Coturiiicops noveboracensis American Coot, Fulica americana American Avocet, Recurtirostva americana Black-necked Stilt, Himantopus mexicanus Mountain Plover, Charadrius montanus Lesser Golden Plover**, Pluvialis dominica Black-bellied Plover**, Pluvialis squatarola 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 L2,3,4,5 3 3,4 3 L3,4,5 L2,3,4,5 L2,3,4,5 L2,3,4,5 L2,4 L5 L2,4 4,5 4,5 1 L2 L2,3,4,5 L2,3,4,5 4 3,4 L4 1 1 2 L3,4 1 1,4,5 5 5 5 5 5 5 1 5 5 5 5 5 5 I 5 5 Semipalmated Plover**, Charadrius semipatmatus 1,5 Killdeer, Charadrius vocifcrus 5 Marbled God wit**, IJmosafedoa 5 Hudsonian Godwit**, Limosa haemastica 5 Long-billed Curlew, Numenius americanus 1,4,5 Greater Y'ellowlegs, Tringa melanoleuca 5 Lesser Yellowlegs, Tringa flavipes 5 Solitary Sandpiper, Tringa solitaria 5 Upland Sandpiper, Bartramia longicauda 1 Buff^-breasted Sandpiper**, Tryngitcs suhruficollis 5 Stilt Sandpiper, Calidris himunto))us 5 Willet, Catoptrophorus scmipalmatus 5 Spotted Sandpiper, Actitis macidaria 5 Long-billed Dowitcher, Limnodromus scolopaceus 5 Wilson's Phalarope, Phalaropus tricolor 5 Red-necked Phalarope, Phalaropus lobatus 5 American Woodcock**, Scolopax minor 4 Common Snipe, Callinago gallinago 5 Pectoral Sandpiper**, Calidris melanotos 5 Red Knot**, Calidris canutus 5 Dunlin, Calidris alpina 5 Sanderling, Calidris alba 5 Baird s Sandpiper**, Calidris bairdii 5 Least Sandpiper, Calidris minutilla 5 Western Sandpiper, Calidris mauri 5 California Gull, Larus californicus 5 Ring-billed Gull, Larus delauarensis 5 Franklin's Gull, Larus pipixcan 5 Bonaparte's Gull, Larus Philadelphia 5 Common Tern, Sterna hirundo 5 Forster s Tern, Sterna forsteri 5 Caspian Tern**, Sterna caspia 5 Black Tern, Chlidonias niger 5 Rock Dove, Columba livia 1,2,3,4,5 Mourning Dove, Zenaida macroura 1,2,3,4,5 Yellow-billed Cuckoo**, Coccyzus anwricanus 4 Black-billed Cuckoo, Coccyzus erythropthalmus 4 Screech Owl, Otus kennicottii 1 Great Horned Owl, Bubo virginianus 1 Long-eared Owl, Asio otus 1 Short-eared Owl, Asio flammeus 1 Snowy Owl, Nyctea scandiaca 1 Northern Hawk-Owl**, Surnia ulula 3 Burrowing Owl, Athene cunicularia 1 Northern Saw-whet Owl, Aegolius acadicus 1 Common Poorwill, Phalaenoptilus nuttallii 1 Common Nighthawk, Chordeiles minor 1 Chimney Swift**, Chaetura pelagica 1 White-throated Swift, Aeronautes saxatalis L Ruby-throated Hummingbird**, Archilochus colubris 4 Broad-tailed Hununingbird, Selasphorus platycercus 4 Calliope Hummingbird, Stellula calliope 4 Rufous Hummingbird**, Selasphorus rufus 1,3,4 Belted Kingfisher, Ceryle alcyon 5 Common Flicker, Colaptes auratus 3,4 Red-headed Woodpecker, Melanerpes erythrocephalus 4 Lewis' Woodpecker, Melanerpes lewis 4 2,3,4,5 2,3,4,5 2,3,4,5 2,3,4,5 2,3,4,5 4 4 4 2,3,4,5 2,3,4,5 2,3,4,5 520 Great Basin Naturalist Vol. 47, No. 3 Yellow-bellied Sapsucker, Sphtjrapicus vahiis 4 Williamson's Sapsucker**, Sphtjrapicus thyroideus 3 Hairy Woodpecker, Picoides villosiis 3,4 Downy Woodpecker, Picoides ptibescens 3,4 Black-backed Woodpecker**, Picoides arctus 3 Three-toed Woodpecker**, Picoides tridactijlus 3 Eastern Kingbird, Tijrannus tijrannus 1,4 Western Kingbird, Tijrannus verticalis 1,4 Cassia's Kingbird, Tijrannus vociferans 1,2,3,4 Say's Phoebe, Saijornis saija 1 Willow Flycatcher, Empidonax traillii 4 Least Flycatcher, Empidonax minimus 4 Hammond's Flycatcher, Empidonax hammondii 3 Dusk\ Flycatcher, Empidonax oherholseri 1,2,4 Western Flycatcher, Empidonax difficilis 4 Western Wood Pewee, Contopiis sordidulus 3,4 Olive-sided Flycatcher, Contopus borealis 3,4 Horned Lark, Eremophila alpestris 1,4 Barn Swallow, Hirundo rustica 5 Cliff Swallow, Hirundo pijrrhonota 5 Violet-green Swallow, Tachijcineta thaJassina 5 Tree Swallow, Tachijcineta bicolor 3 Bank Swallow, Riparia riparia 5 Northern Rough-winged Swallow, Stelp,idopterijx serripennis 5 Purple Martin**, Progne suhis 1,2, 3, 4, .5 Blue Jay, Cijanocitta cristata 4 Steller's Jay**, Cijanocitta stelleri 3 Pinyon Jay, Gymnorhinus cijanocephalus 1,2,3 Gray Jay**, Perisoreus canadensis 3 Black-billed Magpie, Pica pica 1,2,3,4,5 Clark s Nutcracker, Nucifraga cohimhiana 3 Common Raven, Corvus corax 1,2, 3, 4, .5 American Crow, Corvus hrachyrhynchos 4 Black-capped Chickadee, Parus atricapiUus 3,4 Mountain Chickadee, Parus gamheli 2,3,4 American Dipper, Cinchis mexicanus 5 White-breasted Nuthatch, Sitta carolinensis 4 Red-breasted Nuthatch, Sitta canadensis 3,4 Pygmy Nuthatch**, Sitta pygmuea 3 Brown Creeper, Certhia americana 4 WouseV^ren, Troglodytes aedon 4 Rock Wren, Salpinctes ohsoletus 1,2,5 Canyon Wren, Catherpes mexicanus 1,2,5 Marsh Wren, Cistothorus pahistris 5 Gray Catbird, Dumetella carolinensis 4 Brown Thrasher, Toxostoma ritfum 4 Sage Thrasher**, Oreoscoptes montanus 1 American Robin, Turdus migratorius 4 Townsend's Solitaire, Myadestes toicnsendi 3 Hermit Thrush, Catharus guttatus 4 Swainsons Thrush, Catharus ustulatus 3 Veery, Catharus fuscescens 4 Western Bluebird**, Sialia mexicana 2,3 Mountain Bluebird, Sialis currucoides 2 Golden-crowned Kinglet**, Regulus satrapa 3 Ruby-crowned Kinglet**, Regulus calendula 3 Water Pipit, Anthus spinoletta 5 Bohemian Waxwing, Bomhycilla garrulus 2,3,4 Cedar Waxwing, Bomhycilla cedrorum 3,4 Northern Shrike. Lanius excubitor 1,2,4 Loggerhead Shrike, Lanius htdovicianus 1,2,3 European Starling*, Sturnus vulgaris 5 Solitary Vireo, Vireo solitarius Red-eyed Vireo, Vireo olivaceus Warbling Vireo, Vireo gilvus Black-and-white Warbler**, Mniotilta varia Tennessee Warbler, Vermivora peregrina Orange-crowned Warbler, Vermivora celata Nashville Warbler**, Vermivora ruficapilla Yellow Warbler, Dendroica petechia Magnolia Warbler**, Dendroica magnolia Yellow-riunped Warbler, Dendroica coronata Blackburnian Warbler**, Dendroica fusca Chestnut-sided Warbler**, Dendroica pennsijlvanica Blackpoll Warbler**, Dendroica striata Pine Warbler**, Dendroica piniis Palm Warbler**, Dendroica palmarum Ovenbird, Seiurus aurocapillus Northern Waterthrush**. Seiurus noveboracensis Common Yellowthroat, Geothlypis trichas Yellow-breasted Chat, Icteria virens MacGillivra\ s Warbler, Oporornis tolmiei Connecticut Warbler**, Oporornis a gil is Wilson's Warbler, Wilsonia pusilla American Redstart, Setophaga ruticilla House Sparrow*, Passer dotnesticus Boblink**, Dolichonyx oryzivorus Western Meadowlark, Sturnella neglecta Yellow-headed Blackbird, Xanthocephalus xanthocephalus Red-winged Blackbird, Agelaius phoeniceiis Rusty Blackbird**. Euphagus carolinus Brewer s Blackbird, Euphagus cyanocephalus Common Crackle, Quiscalus quiscula Brown-headed Cowliird. Molothrus ater Northern Oriole, Icterus galbula Western Tanager, Piranga ludoviciana Rose-breasted Grosbeak**, Pheucticus ludoviciantis Black-headed Grosbeak, Phencticus melanocephalus Evening Grosbeak, Coccothraustes vespertinus Blue Grosbeak**, Guiraca caerulea Indigo Bunting, Passerina cyanea La7.uli Bunting, Passerina amoena Purple Finch**, Carpodaciis purpureus Cassin s Finch, Carpodacus cassininii House Finch, Carpodacus mexicanus Pine Grosbeak. Pinicola enucleator Rosy Finch, Leucosticte arctoa Hoary Redpoll**, Carduelis hornemanni Common Redpoll, Carduelis flammea Pine Siskin, Carduelis pinus American Goldfinch, Carduelis tristis Lesser Goldfinch**. Carduelis psaltria Red Crossbill, Loxia curvirostra White-winged Crossbill**, Loxia leucoptera Dickcissel**, Spiza americana Green-tailed Towhee, Pipilo chlorurus Rufous-sided Towhee, Pipilo erythrophthalmus Savannah Sparrow, Passerculus sandwichensis Grasshopper Sparrow, Amniodramus savannarum Baird's Sparrow**, Ammodramus bairdii 3,4 4 4 4 4 4 4 4 3 1,3,4 3 4 3 3 4 3 4 4,5 4 3,4,5 4 4 4 4 6,10 1,4 5 5 4 4.5 4 1,4 4 3,4 3,4 4 4 1,3,4 3 3 3,4 3 1,2,3,4,5 1 1 3,4 4 4 3 3 2 1,2,4 1,4 1,5 1 1 July 1987 Anderson etal.. Bighorn Canyon Vertebrates 521 Lark Bunting, Calamospiza mclanoconjs Vesper Sparrow, Pooecetes graniincti.s Lark Sparrow, Chondestes <;,rainvuicus Sage Sparrow**, Amphispiza belli Dark-eyed Junco, Junco hijemulis American Tree Sparrow, Spizella arborea Chipping Sparrow, Spizella passerina Clay-colored Sparrow, Spizella pallida Brewer s Sparrow, Spizella breueri Field Sparrow**, Spizella pusilla Harris Sparrow**, Zonotrichia qucrula White-crowned Sparrow, Zonotrichia leucophrtjs White-throated Sparrow, Zonotrichia albicollis Fox Sparrow, Passerella iliaca Lincoln's Sparrow, Melospiza lincolnii Song Sparrow, Melospiza mclodia McCown s Longspur**, Calcarius mccoivnii Chestnut-collared Longspur**, Calcarius ornatus Lapland Longspur**, Calcarius lapponicus Snow Bunting, Plectropheuax nivalis 1 1,3 1,3,4 1 3,4 4 1,3,4 1,3,4 1,2 1 4 4 1,2,4,5 4 4,5 1 Mammals (scientific names according to Hall [1981]) Masked Shrew, Sorex cinereus 4 Vagrant Shrew, Sorex vagrans 3,4 Dwarf Shrew**, Sorer nanus 3 Water Shrew**, Sorex palustris 3,4 Merriam's Shrew, Sorer merriami 1 Little Brown Myotis, Mtjotis lucifugus 3,4 Long-eared Myotis, Myotis evotis 1,3 Long-legged Myotis**, Myotis volans 3,4 California Myotis, Myotis californicus 1,3 Small-footed Myotis, Myotis leibii 1,2 Silver-haired Bat**, Lasionycteris noctiiagans 3,4 Big Brown Bat, Eptesicus fuscus 3,4 Hoary Bat**, Lasiurus cinereus 1,3,4 Spotted Bat, Eudenna maculatum 1,2,3,4,5 Townsend's Big-eared Bat**, Plecotus toicnsendii 1,4 Mountain Cottontail, Syhilaous nuttallii 2,4 Desert Cottontail, Sylvilagus audubonii 1,2,4 White-tailed Jackrabbit, Lepus townscndii 2,3,4 Least Chipmunk, Eutamias minimus 1,2,3,4,5 Yellow Pine Chipmunk, Eutamias amoenus 2,3 Yellow-bellied Marmot, Mannota flavitentris 1,4 Thirteen-lined Ground Squirrel**, Spermophilus tridecemlineatus 1,2 Black-tailed Prairie Dog**, Cyrunnys ludoticianus White-tailed Prairie Dog**, Cynonujs leucurus Fox Scjuirrel**, Sciurus niger Red S(}uirrel, Tamiasciurus hudsonicus Northern FKing S(juirrel**, Claucomys sab r inns Northern Pocket Gopher, Thonumiys talpoidcs Oli\e-backed Pocket Mouse, Perognathus fasciatus Ord's Kangaroo Rat, Dipodomys ordii Beaver, Castor canadensis Western Har\est Mouse, Rcithrodontomys megalotis Deer Mouse, Peromyscus ntaniculatus Northern Grasshopper Mouse, Onychomys leucogaster Bush\ -tailed Wood Rat, Scotoma cinerea Southern Red-backed \'ole**, Clethrionomys gapperi Meadow Vole**, Microtus pennsylvanicus Montane \'ole, Microtus montanus Long-tailed Vole, Microtus longicaudus Prairie Vole, Microtus ochrogaster Water Vole**, Arvicola richardsoni Muskrat, Ondatra zibethicus House Mouse**, Mus musculus Western Jumping Mouse, Zapus princeps Porcupine, Erithizon dorsatum Coyote, Canis latrans Red Fox, Vulpes lulpes Swift Fox**, Vulpes lelox Black Bear, Ursus amcricanus Raccoon, Procyon lotor Pine Martin**, Martes americana Ermine**, Mustcia erminea Long-tailed Weasel, Mustcia frenata Mink, Mustela lison Badger, Taxidea taxus Spotted Skunk, Spilogale putorius Striped Skunk, Mephitis mephitis River Otter**, Lutra canadensis Mountain Lion, Felis concolor Lynx**, Felis lynx Bobcat, Felis rufus Elk, Cervus claphus Mule Deer, Odocodcus hemionus White-tailed Deer, Odocoileus lirginianus Pronghorn, Antilocapra americana Bighorn Sheep, Otis canadensis 1 1,4 4 3,4 3,4 1,2,3,4 1,2 1,2 5,6,7 1,4,5 1,2,3,4,5 1 1,2,3,4,5 3,4 3,4 1,3,4 4 1 4,5 4,5 2 1,4 1,3,4 1,2,3,4,5 1,2,3,4,5 1 1,2,3,4 4,5 3 3 1,2,3,4,5 4,5 1,3,4 1,2,4,5 1,2,3,4,5 3,4,5 2,3 1,2,3,5 1,2,3,5 1,4,5 1,2,3,4 3,4 1,4 1,2,3 NOTICE TO CONTRIBUTORS Manuscripts intended for publication in the Great Basin Naturalist or Great Basin Natural- ist Memoirs must meet the criteria outHned in paragraph one on the inside front cover. 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Great Basin Naturalist Memoirs No. 1 The birds of Utah. By C. L. Hayward, C. Cottam, A. M. Woodbury, H. H. Frost. $10. No. 2 Intermountain biogeography: a symposium. By K. T. Harper, J. L. Reveal et al. $15. No. 3 The endangered species: a symposium. $6. No. 4 Soil-plant-animal relationships bearing on revegetation and land reclamation in Ne- vada deserts. $6. No. 5 Utah Lake monograph. $8. No. 6 The bark and ambrosia beetles of North and Central America (Coleoptera: Scolytidae), a taxonomic monograph. $60. No. 7 Biology of desert rodents. $8. No. 8 The black-footed ferret. $10. No. 9 A Utah flora. By Stanley L. Welsh $40. No. 10 A reclassification of the genera of Scolytidae (Coleoptera). By Stephen L. Wood. $10. TABLE OF CONTENTS Relationship of western juniper stem conducting tissue and basal circumference to leaf area and biomass. Richard F. Miller, Lee E. Eddleman, and Raymond F. Angell 349 Parasites ofthebowhead whale, Balaenamysticetus. Richard A. Heckmann, Lauritz A. Jensen, Robert G. Warnock, and Bruce Coleman 355 Reproduction of the prairie skink, Eumeces septentrionalis , in Nebraska. Louis A. Somma ^"^-^ List of Idaho Scolytidae (Coleoptera) and notes on new records. Malcolm M. Furniss and James B. Johnson 375 Lizards and turtles of western Chihuahua. Wilmer W. Tanner 383 Dry-year grazing and Nebraska sedge {Carex nebraskensis). Raymond D. Ratliflf and Stanley E. Westfall 422 Diamond Pond, Harney County, Oregon: vegetation history and water table in the eastern Oregon desert. Peter Ernest Wigand 427 Comparison of habitat attributes at sites of stable and declining long-billed curlew populations. Jean F. Cochran and Stanley H. Anderson 459 Estimates of site potential for ponderosa pine based on site index for several southwest- ern habitat types. Robert L. Mathiasen, Elizabeth A. Blake, and Carleton B. Edminster 467 Soil nematodes of northern Rocky Mountain ecosystems: genera and biomasses. T. Weaver and J. Smolik 47J Evidence for variability in spawning behavior of interior cutthroat trout in response to environmental uncertainty. Rodger L. Nelson, William S. Platts, and Osborne Casey 480 Niche pattern in a Great Basin rodent fauna. Edward H. Robey, Jr., H. Duane Smith, and Mark C. Belk 488 Planting depth of 'Hobble Creek' mountain big sagebrush seed. Tracy L. C. Jacobson and Bruce L. Welch 497 Annotated inventory of invertebrate populations of an alpine lake and stream chain in Colorado. John H. Bushnell, Susan Q. Foster, and Bruce M. Wahle 500 Distribution of vertebrates of the Bighorn Canyon National Recreation Area. Stanley H. Anderson, Wayne A. Hubert, Craig Patterson, Alan J. Redder, and David Duvall 512 FHE GREAT BASIN NATURALIST Volume 47 No. 4 31 October 1987 Brigham Young University MCZ LIBRARY f\pv>^ ] 8 1988 HARVARD Uh4iVER3iTY GREAT BASIN NATURALIST Editor. Stephen L. Wood, Department of Zoology, 290 Life Science Museum, Brigham Young University, Provo, Utah 84602. Editorial Board. Kimball T. Harper, Chairman, Botany and Range Science; Ferron L. An- dersen, Zoology; James R. Barnes, Zoology; Hal L. Black, Zoology; Jerran T. Flinders, Botany and Range Science; Stanley L. Welsh, Botany and Range Science. All are at Brigham Young University. Ex Officio Editorial Board Members include Bruce N. Smith, Dean, College of Biological and Agricultural Sciences; Norman A. Darais, University Editor, University Publications; Stephen L. Wood, Editor, Great Basin Naturalist. The Great Basin Naturalist was founded in 1939. The journal is a publication of Brigham Young University. Previously unpublished manuscripts in English pertaining to the biological natural history of western North America are accepted. The Great Basin Naturalist Memoirs series was established in 1976 for scholarly works in biological natural history longer than can be accommodated in the parent publication. The Memoirs appears irregularly and bears no geographical restriction in subject matter. Manuscripts for both the Great Basin Naturalist and the Memoirs series will be accepted for publication only after exposure to peer review and approval of the editor. Subscriptions. Annual subscriptions to the Great Basin Naturalist are $25 for private individuals and $40 for institutions (outside the United States, $30 and $45, respectively), and $15 for student subscriptions. The price of single issues is $12. All back issues are in print and are available for sale. All matters pertaining to subscriptions, back issues, or other business should be directed to the Editor, Great Basin Naturalist, Brigham Young University, 290 Life Science Museum, Provo, Utah 84602. The Great Basin Naturalist Memoirs may be purchased from the same office at the rate indicated on the inside of the back cover of either journal. Scholarly Exchanges. Libraries or other organizations interested in obtaining either journal through a continuing exchange of scholarly publications should contact the Brigham Young University Exchange Librarian, Harold B. Lee Library, Provo, Utah 84602. Manuscripts. See Notice to Contributors on the inside back cover. 10-87 650 31906 ISSN 017-3614 The Great Basin Naturalist Published AT Provo, Utah, by Brigham Young University ISSN 0017-3614 Volume 47 31 October 1987 No. 4 RECORDS OF EXOTIC FISHES FROM IDAHO AND WYOMING Walter R. Courtenav, Ir. , C. Richard Robins", Reeve M. Bailey , and James E. Deacon Abstract. — One exotic poeciliid {Xiphophorus helleri) and two cichlids {Cichlasoma nigrofasciatum and Tilapia mossamhica) are recorded as recently established in thermal springs and their outflows in southern Idaho. Misgurnus anguillicaudatus was collected and is considered as established in the Boise River system. Poecilia mexicana and juvenile hybrid tilapias are recorded from the Bruneau River at Bruneau Hot Springs, Idaho. A reproducing population of X. helleri was found in a spring within the boundaries of Grand Teton National Park, Wyoming. Poecilia reticulata, previously reported from one spring each in Idaho and Wyoming, is recorded from a second spring outflow in Idaho. Simpson and Wallace (1978) and Baxter and Simon (1970) listed the guppy, Poecilia reticu- lata Peters, as the only tropical exotic fish established in Idaho and Wyoming. It was known from a thermal spring in the Little Lost River Valley north of Howe, Butte County, Idaho (Linder 1964), and Kelly Warm Spring, Teton County, Wyoming (within Grand Teton National Park). As part of a continuing investigation of es- tablished exotic fishes in the United States, we (WRC, CRR, RMB) collected fishes from two warm springs in southern Idaho on 7 Sep- tember 1985, a chilly, rainy day, air tempera- ture lie. The first collection site was Warm Springs Creek, Clark County, TUN, R32E, 17.9 km north of Idaho State Highway 22, about 0.5 km from the spring head; tempera- ture was 25.5 C at the site and 27.7 C at the spring. The second site was Barney Hot Spring, Custer County, T12N, R25E,' Little Lost River Valley, 67 km north-northwest of Howe. Temperature in the spring was 27 C in shallows along the perimeter. Two additional collections of fishes were made by WRC and JED in southwestern Idaho on 26 and 27 September 1986, respec- tively. The first was in a heavily vegetated irrigation ditch, the Harton Davis Canal, Ada County, T4N, RIW, along the northeastern edge of Eagle State Park; canal temperature was 17 C. The second was made in the Bruneau River below the Blackstone Gras- mere Road bridge, Bruneau Hot Springs, Owyhee County, T7S, R6E; water tempera- ture was 15 C in the river, 20-22 C in the collecting area, and 23 C in a thermal inflow just upstream of the collection site. Fishes were sampled by WRC in Kelly Warm Spring, 1.6 km north-northeast of the town of Kelly, Teton County, Wyoming, T42N, R115W, on 23 July 1984. Additional observations were made from the surface on 13 September 1985. Temperature in this spring is nearly constant, 25-27 C (P. S. Hayden, personal communication). Methods and materials. — Fishes were sampled in each spring system and the 'Department of Biological Sciences, Florida Atlantic University, Boca Raton, Florida 334.31 Rosenstiel School of Marine and Atmospheric Science. University of Miami, Miami, Florida 33149. Museum of Zoology, University of Michigan, Ann Arbor. Michigan 4H109. Department of Biological Sciences. University of Nevada at Las \'egas. Las Vegas, Nevada 891.54. 523 524 Great Basin Naturalist Vol. 47, No. 4 irrigation ditch with galvanized minnow traps (44 X 25 cm, 6.4-mm mesh). Canned dog food was used in traps as bait in the two Idaho springs, and bread was used at the Wyoming site; traps placed in the irrigation ditch were unbaited. Trapping time was 30 minutes in Warm Springs Creek, about 45 minutes in the irrigation ditch, and one hour in the other springs. Fine mesh dipnets also were used at the two Idaho springs and their outflows, and nylon minnow seines (4.6 x 1.8 m, 6.4-mm mesh) were used in the Bruneau River. Ap- proximately 75% of the Kelly Warm Spring pool was observed underwater using face mask and snorkel during the trapping period; additional surface observations were made on 13 September 1985 from the pool perimeter with polaroid glasses. Standard length measurements were taken to the nearest mm with dial calipers. Speci- mens are deposited in the collections of Flor- ida Atlantic University (FAU), University of Michigan Museum of Zoology (UMMZ), and University of Nevada at Las Vegas (UNLV). Results Idaho Fishes collected in the narrow (about 0.75-1.5 m) Warm Springs Creek included 120 guppies (13-36 mm SL, UMMZ 213369 and FAU WRC-ID-1) and 121 green sword- tails, Xiphophorus helleri Heckel (19-66 mm SL, UMMZ 213370 and FAU WRC-ID-1). No native fishes were seen or collected. The spring head and its immediate outflow doubtless provide thermal refuge during win- ter months. In Barney Hot Spring and the upper end of Barney Creek, we collected 29 guppies (13-27 mm SL, UMMZ 213371 and FAU WRC-ID-2), 95 green swordtails (14-36 mm SL, UMMZ 213372 and FAU WRC-ID-2), 19 amelanic convict cichlids, Cichlasoma nigro- fasciatum (Gunther) (15-92 mm SL, UMMZ 213373 and FAU WRC-ID-2), and 142 Mozambique tilapia, Tilapia mossambica (Pe- ters) (19-78 mm SL, UMMZ 213374 and FAU WRC-ID-2). Within the spring, all fishes were collected from and observed in the perimeter shallows. Guppies were not as nu- merous as reported by Linder (1964) and were rare in the pond. Tilapia nests were located primarily at the southern end of the approxi- mately 15-m-diameter spring pool, near the outflow (Barney Creek). Guppies, swordtails, and a few convict cichlids were found in the creek, the cichlids only near the pond out- flow. No other fishes were observed or col- lected at this location. Apparently the intro- duction of cichlids has resulted in the near elimination of guppies from the pond. One Oriental weatherfish, Misgurnus an- gidUicaudatus (Cantor) (102 mm SL, UNLV 1951), was collected from Harton Davis Canal near Eagle. A pair of shortfin mollies, Poeciliainexicana Steindachner, {6 35 and 9 40 mm SL, UMMZ 213783) and 10 juvenile tilapias (17-23 mm SL, UNLV 1952), probably hy- brids of Tilapia mossambica x T. hornorum Trewavas, were captured in the Bruneau River at Bruneau Hot Springs. The collection site was adjacent to a thermal inflow (23 C) that drains from ponds of a nearby aquacul- ture facility. In addition to the two exotic spe- cies, common carp, Cyprinus carpio Lin- naeus, and orange-spotted sunfish, Lepomis humilis (Girard) were taken. Native fishes in the area included redside shiner, Richardso- nius balteatus (Richardson) (abundant), chis- elmouth, Acrocheilus alutaceus Agassiz & Pickering, northern squawfish, Ptychocheilus oregonensis (Richardson), and large-scale sucker, Catostomus macrocheilus Girard (all common). Collections were made in water to 1 m in depth. Wyoming Sixty-five guppies (18-35 mm SL, FAU WRC-'WY-l) and 203 green swordtails (15-68 mm SL, FAU WRC-WY-1) were collected in minnow traps from Kelly Warm Spring. Also collected and released were 37 Utah chubs, Gila atraria (Girard), and 2 speckled dace, Rhinichthys osculus (Girard). Observations using face mask and snorkel showed that Utah chubs were common over open areas and near vegetation in the south- western part of the Y-shaped spring pool (ap- proximately 110 X 24 m; P. S. Hayden, per- sonal communication). Speckled dace were observed primarily around spring boils over open sand and fine gravel, away from the pool perimeter. Green swordtails were common in the perimeter shallows and abundant in aquatic vegetation along the southeastern shore; guppies were also concentrated at the October 1987 COURTENAY ETAL.: IDAHO-WYOMING ExOTIC FISHES 525 kitter site. Both exotics showed the same dis- tribution when the pool was observed from the surface in 1985. Discussion These records of green swordtails are the first for Idaho and Wyoming, and those of Oriental weatherfish, shortfin mollies, con- vict cichlids, Mozambique tilapias, and hy- brid tilapias are the first for Idaho. Introduc- tions of guppies, the other tropical exotic fishes except hybrid tilapias, and the Oriental weatherfish resulted from releases of aquar- ium fishes. Juvenile hybrid tilapias escaped from a culture facility. Cichlids were reported to have been released in Kelly Warm Spring, Wyoming (P. S. Hayden, personal communi- cation), but none was observed or collected. No native fishes were collected at the Idaho springs. That native species occupied those waters in recent times is doubtful. Barney Hot Spring is isolated from the Upper Snake River by the Lost River Sinks downstream, and its outflow sinks below the surface before enter- ing the Little Lost River (Linder 1964). More- over, there is an absence of warm-water fishes. Simpson and Wallace (1978) indicated only salmonids and shorthead sculpin. Coitus confusus Bailey & Bond, as native in the Little Lost River drainage of Idaho. The Oriental weatherfish was the only fish collected from the irrigation ditch at Eagle State Park. V. K. Moore (personal communi- cation) reported the presence of an unidenti- fied "Chinese loach" in the Boise River sys- tem and added that it had been there for several years, with a few specimens having been captured. Although we collected only one specimen, we consider the species as es- tablished. Self-sustaining populations of this exotic are also present in California and Mich- igan (Courtenay et al. 1986). The capture of a pair of shortfin mollies in the Bruneau River in the same shallow, vege- tated, warm inflow area of the river from which the juvenile Tilapia were collected may indicate that this species is established imme- diately upstream in Indian Bathtub, an area of inflowing thermal water. Poeciliids have been reported previously from Bruneau Hot Springs (V. K. Moore, personal communica- tion), and we believe Indian Bathtub is the nost likely site where they were seen or col- lected. Shortfin mollies are established in California and Nevada (Courtenay et al. 1986). The species was also reported as estab- lished in Trudau Pond, Madison County, Montana (Brown 1971), but no specimens were collected there in September 1985. Tilapia culture in thermal waters in south- ern Idaho has expanded recently. Blue tilapia, Tilapia aurea (Steindachner), have been cul- tured for several years in Hagerman Valley, Twin Falls County, and may have established following escape in the Snake River near natu- ral thermal inflows (V. K. Moore, personal communication). A similar situation occurred in Pennsylvania where escaped blue tilapia established in the lower Susquehanna River and now overwinter near power plant thermal effluents (Skinner 1984, 1986). The culture facility near Bruneau Hot Springs seemed to be of recent construction. The "red" tilapias being cultured there appear to be a hybrid that is being used increasingly in aquaculture operations in Idaho and elsewhere. If this hy- brid is fertile, as many tilapia hybrids are, we predict that it will become established near thermal inflows in the Bruneau River. Kelly Warm Spring drains into the upper Snake River via Mormon Row Ditch into downstream Ditch Creek. A second irrigation ditch, Savage Ditch, permits water to be di- verted from the Gros Ventre River into Mor- mon Row Ditch, just below the outflow from Kelly Warm Spring. The spring was excavated in the late 1940s for the purpose of increasing flow into those ditches (P. S. Hayden, per- sonal communication). A flow-control struc- ture separates the spring pool from the ditches. Baxter and Simon (1970) recorded Utah chubs, speckled dace, and Utah suckers, Catostomus ardens Jordan & Gilbert, from Kelly Warm Spring. Utah chubs and suckers live in warm spring outflows (Jordan 1891, Linton 1893, R. D. Jones, personal communi- cation). Speckled dace commonly inhabit warm springs (Sigler and Miller 1963). No Utah suckers were collected or ob- served in Kelly Warm Spring in July 1984. Although suckers are not easily trapped, adults are generally readily observed under- water (Courtenay et al. 1985). Suckers may have been present near the outflow structure, the only area of the spring pool not observed with mask and snorkel. P. S. Hayden 526 Great Basin Naturalist Vol. 47, No. 4 (personal communication) indicated that they were seen in the pool some five to six years prior to 1984. He also stated that the structure is opened periodically and, depending on out- flow volume and speed, could permit entry from the ditches. Most of the exotic fishes reported herein are restricted to warm waters and do not ap- pear to represent a threat to native fishes in Idaho or Wyoming. Nevertheless, they serve as additional examples of unauthorized intro- ductions, even in areas remote to civilization and, in one case, within a national park. Obvi- ously, those persons introducing these tropi- cal fishes go to considerable lengths to estab- lish them. In the Boise and Bruneau rivers, and in Kelly Warm Spring, sympatry with the native fauna could lead to adverse conse- quences. Introductions in similar situations in other states have been implicated in the de- chne and extinction of native fishes (e.g.. Miller 1961, Minckley and Deacon 1968, Deacon et al. 1964, Lachner et al. 1970, Dea- con 1979, Courtenay and Deacon 1982, Courtenay et al. 1985, Heckmann et al. 1987). Acknowledgments Marian Bailey and Francine S. Courtenay assisted with fish traps and data recording. Special thanks are due William R. Gould and Robert G. White for the loan of collecting gear used in Idaho spring systems. We thank Kent W. Ball, Virgil K. Moore, and Richard L. Wallace for providing information on collect- ing localities in Idaho. We also thank Robert P. Wood for his cooperation and, especially, Peter S. Hayden, National Park Service, Grand Teton National Park, for providing hy- drographic and hydrologic data on Kelly Warm Spring, information on the history of introductions there, and some specimen preservation supplies. Ronald D. Jones, U.S. Fish and Wildlife Service, Yellowstone Na- tional Park, provided the senior author with information on fish distributions in thermal Witch Greek. The senior author is grateful to Florida Atlantic University for sabbatical sup- port and to Arizona State University for an appointment as Maytag Distinguished Visit- ing Professor, which assisted the completion of this project. Literature Cited Baxter. G T . and J R Simon. 1970. Wyoming fishes. Bull. 4, Wyoming Game and Fish Dept., Cheyenne. 168 pp. Brown. C J D 1971. Fishes of Montana. Big Sky Books, Bozeman, Montana. 207 pp. Courtenay. W R , Jr . and J E Deacon. 1982. Status of introduced fishes in certain spring systems in southern Nevada. Great Basin Nat. 42; 361-366. COL'RTENAY. W R , Jr . J E Deacon. D W Sada, R C Allan, and G. L. Vinyard 1985. Comparative status of fishes along the course of the pluvial White River, Nevada. Southwestern Nat. 30; .503-524. Courtenay, W R , Jr , D A Hensley, J N Taylor, and J. A. McCann 1986. Distribution of exotic fishes in North America. Pages 675-698 in C. H. Hocutt and E. O. Wiley, eds.. Zoogeography of North American freshwater fishes. John Wiley & Sons, New York. Deacon, J. E. 1979. Endangered and threatened fishes of the west. Great Basin Nat. Mem. 3; 41-64. Deacon, J E., C. Hubbs, and B Zahuranec 1964. Some effects of introduced fishes on the native fish fauna of southern Nevada. Copeia 1964; 384-388. Heckmann, R A , J E Deacon, and P D Greger 1987. Parasites of the woundfin minnow, Plagopterus argentissimiis, and other endemic fishes from the Virgin River, Utah. Great Basin Nat. 46(4): 662-676. Jordan, D S 1891. A reconnaissance of the streams and lakes of the Yellowstone National Park, Wyoming, for the purposes of the U.S. Fish Commission. Bull. U.S. Fish Comni. 9; 41-63. Lachner. E A . C R Robins, and W R. Courtenay, Jr. 1970. Exotic fishes and other aquatic organisms introduced into North America. Smithsonian Con- trib. Zool. .59; 1-29. Linder, a. D 1964. The guppy, Lebistes reticulata (Pe- ters), from a hot spring in Idaho. Copeia 1964; 708-709. Linton. E. 1893. On fish entozoa from Yellowstone Na- tional Park. Rept. U.S. Fish Comm. 1889-1891; .545-546. Miller, R R 1961. Man and the changing fish fauna of the American southwest. Pap. Mich. Acad. Sci., Arts, and Letters 46; 365-404. Minckley. W L., and J. E Deacon 1968. Southwestern fishes and the enigma of "endangered species." Science 159; 1424-1432. SiGLER. W F , and R R Miller 1963. Fishes of Utah. Utah Dept. Fish and Game, Salt Lake City. 203 pp. Simpson, J C and R. L. Wallace 1978. Fishes of Idaho. University Press, Idaho, Moscow. 237 pp. Skinner, W F 1984. Oreochromis aureus {Steindachner: Cichlidae), an exotic fish species, accidentally in- troduced to the lower Susquehanna River, Penn- sylvania. Proc. Pennsylvania Acad. Sci. 58; 99-100. 1986. Susquehanna River tilapia. Fisheries (Bethe-sda) 11(4); 56-57. REVISION OF SAHNIOCARPON HARRISII CHITALEY & PATIL BASED ON NEW SPECIMENS FROM THE DECCAN INTERTRAPPEAN BEDS OF INDIA E. M. V. Nambudiri', William D. Tidwell", and Shya Chitaley^ Abstract — New specimens oi Sahniocarpon harrisii Chitaley & Patil were collected from the Deccan Intertrap- pean beds at Mahgaon Kalan in central India. These specimens form the basis for this reinvestigation of the species and an emended diagnosis. A tuberculated seed coat, a chalazal haustorium, and the bitegmic nature of the testa can be observed in the new specimens. These features were not included in the original description. Although the extant genera of Clusiaceae and Sahniocarpon are not similar in all aspects, they are close enough to tentatively assign Sahniocarpon to this tropical family. Well-preserved plant fossils, a majority of them angiospermic, have been noted from the Deccan Intertrappean beds exposed at Mo- hgaon Kalan in central India. The fossil plants from this locality include woods, roots, leaf impressions, flowers, and fruits. Petrified wood is the predominant fossil material from these beds, whereas fruiting structures are rare. The first fruiting structure documented from the Mohgaon Kalan locality was Enigmo- carpon parijai, a multilocular, many-seeded loculicidal capsule described by Sahni (1943). Since this publication, only a few additional dicot fruits have been reported from this local- ity by later workers. Jain (1964) and Nam- budiri (1969) described fossil species oflndo- carpa that were related to modern genera of Guttiferae, and two new genera of fossil fruits with malvaceous affinities were detailed by Chitaley and Nambudiri (1973) and Chitaley and Sheikh (1971). The only other dicot fruit known from the Deccan Intertrappean series at this locality is Sahniocarpon harrisii Chitaley & Patil (1971). Additional specimens of this species collected by EMVN from the same Intertrappean beds exposed at Mohgaon Kalan, Chhindwara dis- trict, Madhya Pradesh, India (Fig. 1), are de- scribed here. The reinvestigation and subse- quent emended diagnosis of Sahniocarpon are based on these new specimens. The age of the Deccan Traps has long been a subject of much debate. Geologists, such as Krishnan (1969) and Wadia (1966), generally regard the Deccan volcanism as an Upper Cretaceous activity. This view was held by many researchers until Crooksank (1937) and Sahni (1937) reviewed the paleontological and geochemical data and, based upon their findings, suggested an Early Tertiary age for these beds. Plant fossils such as Nipadites (Nypa) (Rode 1933), the freshwater alga, Chara (Malcolmson 1837, Rao and Rao 1935), and palms are indicative of an Early Tertiary age (Sahni 1937). Because of mass extinctions associated with the iridium anomaly, the Cre- taceous-Tertiary boundary has recently re- ceived much attention. Through this research much radiometric data have been generated concerning the Deccan Traps. The Potas- sium-Argon dates from these rocks suggest that the volcanic activity spanned a consider- ably longer time period than originally thought. Alexander (1981) reviewed the K-Ar dates for the Deccan Traps in the Chhindwara area, the collecting locality for the Sahniocar- pon fruits, and suggested an age of 47 Ma. for the volcanic Trap strata. This is in agreement with Sahni's original interpretation that the Intertrappean beds at Mohgaon Kalan, Chhindwara district, is of Early Tertiary age. Paleomagnetic studies of the Deccan Traps note a reversely magnetized lower and a nor- mally magnetized upper traps (Athavale et al. 1963, Clegg et al. 1956, Verma and Pulliah 1967). Geomagnetic field reversal, an Upper Cretaceous phenomenon, is recognized in both continental and oceanic sequences and is easily discerned in the North Indian Ocean Energy Research Unit. University of Regina, Regina, Saskatchewan. Canada S4S 0A2. Department of Botany and Range Science, Brigham Young University, Provo. Utah 84602 *rhe Cleveland Museum of Natural History, Wade Oval, Universitv Circle, Cleveland, Ohio 44106. 527 528 Great Basin Naturalist Vol. 47, No. 4 Fig. 1. The regional map showing the position of the Indian subcontinent. The Mohgaon Kalan locaUty in Chhindawar district is indicated. sequence (Scalter and Fischer 1974). How- ever, data accumulated from plant fossils sug- gest that the Intertrappean beds in the Chhindwara area are Paleocene to Early Eocene in age. Systematic Paleobotany Sahniocarpon harrisii Chitaley & Patil (1971) Specific diagnosis (emended). — Fruit round to oval (6.5 X 7.5 mm), pentalocular, septicidal capsule; pericarp (0.85-1.6 mm thick) divided into outer zone (0.35-0.7 mm) of fleshy or hard tissues (each cell 27-36 |xm in size) and an inner zone of fleshy or aerenchy- matous cells; dehiscence along the septae, septae five, meeting at the center of the fruit; placentation axile; each locule single-seeded; seeds obovate, anatropous, with 3 attenuated, chalazal outgrowths; seeds endospermic, bitegmic, testa (115 \xm wide), tuberculated; embryo axis (3071 X 629 |xm) with a radicle towards the micropylar end, embryonic leaves, plumule and a chalazal haustorium at the chalazal end; seeds attached to the base of the axile placentum by a short funicle (592 |xm long). Description This permineralized fruit (7 x 7.2 mm) is a round to oval, pentalocular, septicidal capsule (Figs. 2, 3). The dry pericarp (1.5 mm thick) is differentiated into an outer zone of compara- tively hard tissues and an inner fleshy zone (Fig. 18). The locules are separated by five septae (Figs. 5, 6). At the distal end of the fruit, the locules split along septal margins (septicidal dehiscence; Fig. 4). A single, anat- ropous seed, completely infilling the locule (Fig. 9), is added to the base of the axile pla- centum by a short (592 \xm long) funicle (Fig. 14). Each seed is obovate with a narrow mi- cropylar end and a broad chalaza (Fig. 5). At the chalazal end, these seeds have three trian gular, attenuated, stony outgrowths (Figs. 4, October 1987 Nambudirietal: Plant Fossils 529 Fig. 2. Reconstruction oi Sahniocarpon harrisii Chita- ley & Patil (not to scale). 5). The testa is hard and bitegmic, derived from outer and inner integuments (Figs. 7, 10, 12, 15). The outer integument is tubercu- lated by fleshy outgrowths arising from the testa (Fig. 12). The cotyledonary cells are poorly preserved. The embryo axis (3071 \xm long and 629 jxm wide) is comparatively large and is differentiated into a radicle, located at the micropylar end, and a plumule at the cha- lazal end (Fig. 9). Embryonic leaves, arising from the plumule and formed by the differen- tiation of the shoot apex, are clearly visible. An elongated haustorium is attached to the embryo at the chalazal end (Fig. 9). Pericarp. — The pericarp is differentiated into outer and inner layers (Fig. 18). The outer pericarp is formed of polygonal, thick- walled, compactly arranged cells (mean di- ameter of 35.5 |xm). This tissue is covered by a single-layered epidermis, composed of rectangular cells (12 \xm). This epidermis is occasionally covered by cuticle. Conversely, cells of the inner pericarp (24.2 [xm) are formed exclusively of thin-walled, round to oval, or polygonal cells. Vascular bundles tra- verse the inner pericarp. Vasculature OF THE fruit.— The main lat- eral vascular bundle can be traced throughout the inner pericarp (Fig. 13). This vascular bundle in transverse section (126 \xm X 97 |xm) shows two main metaxylem vessel ele- ments (20 |jLm) and four to five protoxylem vessel elements (14 |jLm). A layer of sclerotic tissues surrounds each bundle (Fig. 13). This main vasculature of the fruit supplies branches into the septae, which are composed of parenchymatous cells. Longitudinally ori- ented vessel elements of the septum have spiral wall thickenings (Fig. 11). Although cells of the phloem tissue are not easily dis- cernible, it is assumed that the thin-walled cells in the vascular bundles are functional phloem cells. Seeds. — The testa (115 \xm wide) is formed from the outer and inner integuments of the bitegmic ovules (Figs. 7, 10, 12, 15). Two to five layers of highly thick-walled cells form the outer testa. Apparently due to attenuated ap- pendages, the testa attains a maximum thick- ness at the chalazal end. Cells of these ap- pendages are exclusively thick walled. The inner testa is comparatively less sclerotic. Eight to ten layers of round to polygonal cells form the inner testa. A distinct layer of barrel- shaped cells (31 fxm x 16.8 |xm), separating the outer from the inner testa (Figs. 7, 10, 12, 15), is developed from the innermost layer of the outer integument. Outer walls of these cells are thin walled, whereas the inner and tangential walls are thickened (Fig. 15). Cells of the testa in surface view are elongated with sinuous cell walls (Fig. 8). Round to oval, fleshy outgrowths (Fig. 12), similar to elaiosomes (Esau 1979), give the seeds a tuberculated appearance. These tu- bercles are formed of thin-walled, polygonal cells. Like septal cells, cells of the elaiosomes have undergone considerable degradation due to the attack of fungi. In fact, fungal myce- lia and spores are clearly visible inside the fruit and seeds. The anatropous nature of the seeds is ascertained by the presence of a mi- cropyle (14 |xm wide) located near the funicle (Figs. 10, 14). Both outer and inner integu- ments take part in the formation of the mi- cropylar duct. Vascular bundles are clearly visible at the chalaza. Embryo. — The embryo (3071 \xm x 629 |xm) completely fills the seed cavity. Cells of this embryo are polygonal (wherever pre- served), thin walled, and parenchymatous 530 Great Basin Naturalist Vol. 47, No. 4 Figs. 3-8. Sahniocarpon harrisii Chitaley & Patil: 3, Fruit in l.s. showing septicidal dehiscence, nature of pericarp, seed coat, and embryo axis (4.5X); 4, Fruit in l.s. showing dehiscence at the distal end (26X); 5, Fruit in l.s. showing three seeds; the central seed is attached to the base of the axile placentum by a short funicle (15X); 6, Fruit in t.s. shows each locule containing a single seed (7X); 7, Testa in oblique section showing the outer and inner integuments (140X); 8, Cells of testa in surface view (300X). October 1987 Nambudiri et al. : Plant Fossils 531 Figs. 9-13. Sahniocarpon harrisii Chitaley & Patil: 9, Seed in l.s. showing embryo axis; cells of the radicle (r), plumule (p) with embryonic leaves (e), and a haustorium (h) attached to the chalazal region (30X); 10, Seed in l.s. to show the micropyle (m) formed of outer and inner integuments (130X); 11, Vascular bundle in the pericarp showing vessel elements with helical thickenings (20X); 12, Testa in l.s. showing elaiosomes (es) (250X); 13, Pericarp in l.s. showing vascular bundles (120X). 532 Great Basin Naturalist Vol. 47, No. 4 (Figs. 9, 16). Cells of the radicle, also par- enchymatous, are well preserved. Comparisons and Affinities On comparison with the several dicotyle- donous fruits from the Deccan Intertrappean series, it is clear that these permineralized fruit specimens are, in fact, Sahniocarpon harrisii. Sahni (1943) described a loculicidal capsule, Enigmocarpon parijai, having lyth- raceous and sonneratiaceous affinities. Sah- niocarpon harrisii differs from Enigmocarpon parijai in having single-seeded locules and also in being a septicidal rather than a loculici- dal capsule. Enigmocarpon has several seeds per locule. In addition, the hypostase tissue in Enigmocarpon is absent in Sahniocarpon har- risii . The other dicotyledonous fruits known from these Intertrappean beds are Indocarpa intertrappea Jain (1964), /. mahabalei Nam- budiri (1969), Harrisocarpon sahnii Chitaley & Nambudiri (1973), and Daberocarpon ger- hardii Chitaley & Sheikh (1971). Daberocar- pon gerhardii is a multilocular fruit with a single seed in each locule. Chitaley and Sheikh (1971) suggested affinities for this genus of fruit with such malvaceous genera as Abutilon indicum, Malva parsiflora, Malva sylvestris, Malvastrum sp., Sida cordifolia, and Sida rhombifolia . Harrisocarpon sahnii is also a septicidal capsule but contains two seeds per locule. Sahniocarpon harrisii is different from both species of Indocarpa in having a stony seed coat as compared to the sarcotesta in Indo- carpa. Moreover, Indocarpa is a multi- seeded, septifragal capsule. Chitaley and Patil (1971) stated that the Sahniocarpon pericarp is fleshy with aeren- chymatous cells in the inner layers of the peri- carp. The specimens described here, how- ever, indicate that the pericarp is divisible into an outer zone of hard tissues and an inner zone of fleshy tissues. The pericarp in these new specimens lacks air chambers. Such dif- ferences are, perhaps, induced by ecological conditions and should not be used for discrim- inating at specific levels. The abundance of aerenchymatous tissue in the specimens de- scribed by them suggests that the parent plants were perhaps growing around several small lakes that formed an integral part of the Deccan landscape during the Intertrappean time. Another feature of interest is the nature of the testa. Chitaley and Patil (1971) men- tioned that the testa is composed of three zones, the outer and inner zones of thin- walled parenchymatous cells and a central zone of elliptical cells with radial wall thicken- ings. Except for the sclerotic outer and inner testa, the structure of the seed coat as de- scribed by Chitaley and Patil (1971) is some- what similar to the new specimens. A layer of barrel-shaped cells, separating the outer and inner testa, is the innermost layer of the outer integument. Ontogenetically, bitegmic seeds of Cruciferae develop a similar structure in their testa (Vaughn and Whitehouse 1971). Esau (1979) suggested that if subepidermal parenchyma is present in the outer integu- ment, they are either crushed or become thick walled. Such thick-walled cells may have formed during the development of the seed coat in these new specimens of Sahnio- carpon . The seeds are anatropous in both Sahniocarpon and our new specimens, but in the latter the seeds are attached to the base of the axile placentum by a funicle. For purpose of clarity, we have used the term funicle rather than raphe (Chitaley and Patil 1971). The raphe is a ridge formed by adnation of the funiculus with the ovule (Esau 1979). While such minor differences exist between the type specimens of Sahniocarpon harrisii, it is evi- dent that the specimens described here be- long to the genus Sahniocarpon. There are features in the new specimens that were not originally described by Chitaley and Patil (1971) for Sahniocarpon harrisii, such as, the tuberculated seed coat, the chalazal hausto- rium, and the bitegmic nature of the testa. The specific diagnosis of the Sahniocarpon harrisii has been, therefore, emended to in- clude these additional characteristics. Several features present in the Sahniocar- pon fruit may be primitive. The majority of angiosperms (84.6% of dicotyledons; Davis 1966) have anatropous ovules. Although Sporne (1974) suggested that orthotropous ovules should be regarded primitive. Fames (1961) and Takhtajan (1969) noted that or- thotropous ovules were derived from the ana- tropous condition and should be considered advanced. There is a general agreement, how- ever, that bitegmic ovules are primitive in comparison with the unitegmic ovules (Joshi 1939, Maheswari 1950). Many angiospermous October 1987 NaMBUDIRI ET AL. : PLANT FOSSILS .1: -'*' ' ^-^'f 533 Figs. 14-18. Sahniocarpon harrisii Chitaley & Patil: 14, Seeds in Is. showing attachment to the axile placentation (42X); 15, Testa in 1. s. showing outer (oi) and inner (ii) integuments (32()X); 16, Seed in 1. s. showing cellular nature of the embryo axis (lOOX); 17, Seeds in t.s.; the seed at the top of the picture is in surface view (26X); 18, Fruit in l.s. showing pericarpic tissues (35X). 534 Great Basin Naturalist Vol. 47, No. 4 Table 1. Range of characters in subfamilies Clusioideae and Hypericoideae (based on information in Corner 1976, Davis 1966, Lawrence 1951). Character Clusioideae Hypericoideae Fruit Nature of fruit Number of locules Number of ovules Orientation of ovules Nature of ovules Placentation Seeds Microphyle Testa: No. of integuments Outer integument Inner integument Nucellus Endosperm Embryogeny Capsule, berry, or drupe 1-many 1-many Usually straight Anatropous, hemianatropous Axile, basal, or infrequently parietal Formed of outer integument Bitegmic 2-30 cells thick 2-15 cells thick Tenuinucellate Nuclear Solanad type Capsule or berry 3-5 Numerous Straight or curved Anatropous Axile, rarely parietal Formed of both integuments Bitegmic 2 cells thick 2-6 cells thick Tenuinucellate Nuclear Onagrad type families represented in the Cretaceous floras, as well as 62% of extant dicotyledons, have two distinct integuments producing the seed coat (Sporne 1974). A sarcostesta (Corner 1953) is considered more primitive (van der Fiji 1955) than a sclerotesta as in Sahniocar- pon. Sporne (1974) noted that the septa in axile placentation is a single unit formed by fusion of individual, involute carpels. Members of both Guttiferae and Lecythi- daceae are present in the fossil floras of India. Jain (1964) and Nambudiri (1969) described species of dicotyledonous fruit resembling Guttiferae. Indocarpa and the Sahniocarpon specimens were collected from the same In- tertrappean locality at Mahgaon Kalan. Lakhanpal and Bose (1951) described leaves of Garcenia and Calophyllwn (Guttiferae) from the Tertiary beds in Rajastan. Wood genera such as Kayeoxylon assamicum (Chowdhury and Tandon 1949) and Guttiferoxylon indicum (Ramanujam 1960) also occur in the Tertiary beds of India. Shallom (1960) reported Bar- ringtonioxylon deccanense, a fossil wood assignable to Lecythidaceae, from the Deccan Intertrappean beds of India. On comparison with extant genera, the Sahniocarpon fruit is found to resemble fruits of members of the families Clusiaceae (Gut- tiferae sensu stricto; Cronquist 1968, 1981, Takhtajan 1969) and Lecythidaceae. Tax- onomists have treated Clusiaceae and Hyperi- aceae as separate families or subfamilies un- der Clusiaceae. We have adopted Cronquist's (1981) system in which subfamilies Clu- sioideae and Hypericoideae have been in- cluded under the family Clusiaceae. The sub- family Clusioideae has capsular fruits, as in Sahniocarpon, with 3-5 carpels forming the fruit. These subfamilies have 1-numerous seeds attached to the base of the axile placen- tum. Moreover, the seeds are bitegmic. The difference between Sahniocarpon and the several genera of Clusioideae is that micropy- les in seeds of the modern genera of this sub- family are formed entirely of their outer integuments (Table 1, Davis 1966). Sahnio- carpon differs from Hypericoideae as well, the major difference between them being the number of seeds in each locule of the fruit. In Lecythidaceae, the ovules are anatropous. They are bitegmic but the micropyle is formed only of the inner integument (Venkateswarulu 1952). Although the genera of Clusiaceae are not similar to Sahniocarpon in all aspects, the resemblances between the extant genera of this family and Sahniocarpon are close enough to tentatively assign this genus to the Clusioideae of the tropical family Clusiaceae. Acknowledgments The authors are grateful to Dr. Greg Retal- lack of the Department of Geology, Univer- sity of Oregon, for reviewing an earlier ver- sion of the manuscript. We also thank Naomi Hebbert for the reconstruction. October 1987 Nambudiri etal: Plant Fossils 535 Literature Cited Alexander, P. D 1981. Age and duration of Deccan volcanism. In: K. V. Subbarao and R. N. Sukheshala, eds., Deccan volcanism and related Basalt Provinces in other parts of the world. Geol. Soc. India Mem. 3: 244-258. Alvarez, L W . W Alvarez. F Asaro, andH V Michel 1980. Extraterrestrial cause for the Cretaceous- Tertiary extinction. Science 208: 1095-1108. ATHAVALE, R. N , C R'VDHAKRISHNAMUR'n', AND P. W SA- hasrabudhe 1963. Paleomagnetism of some In- dian rocks. Geophys. J., London 7: 304-313. Chitaley, S D , AND E M V Nambudiri 1973. Harriso- carpon sahnii gen. et sp, nov. from the Deccan Intertrappean beds of Mohgaon Kalan, District Chhindwara. Geophytology 3: 36-41. Chitaley, S. D , and G V Patil 1971. Salmiocarpon harrisii gen. et sp. nov. from the Mohgaon Kalan beds of India. Palaeobotanist 20: 288-292. Chitaley, S D , and M T Sheikh 1971, A ten locular petrified fruit from the Deccan Intertrappean se- ries of India. Palaeobotanist 20: 297-299. Chowdhury, K. a., and K. N. Tandon 1949. Kayeoxylon assamicum gen. et sp. nov. , a fossil dicotyledonous wood from Assam. Proc. National Inst. Sci. India 19: 361-369. Clegg, J A , E R Deutsch. and D H Griffith 1956, Rock magnetism in India. Phil. Mag. Ser. 8: 419. Corner, E J H 1953. The Durian theory extended. Phytomorphology 3; 465-476. 1976. The seeds of Dicotyledons. Vol. 1. Cam- bridge University Press. Cronquist, a. 1968. The evolution and classification of flowering plants. Houghton Mifflin Co., Boston. 1981. An integrated system of classification of flowering plants. Columbia University Press, New York. Crooksank, H 1937, The age of the Deccan Trap. Disc. Geol. Sect., 24th Indian Sci. Congr., Hyderabad: 459-464. Davis, G L 1966. Systematic embryology of the an- giosperms. John Wiley and Sons, Inc., New York. Eames, A J 1961. Morphology of angiosperms. McGraw- Hill Book Co. , New York. Esau, K. 1979. Anatomy of seed plants. 2d ed. Wiley Eastern Ltd., New Delhi. Jain, R. K 1964. Indocarpa intertrappea gen. et sp. nov., a new dicotyledonous fruit from the Deccan Inter- trappean Series, India. Bot. Gaz. 125: 26-33. Joshi. a C 1939. Morphology of Tinospra cordifolia, with some observations on the origin of the single integument, nature of synergidae and affinities of Menispermaceae. Amer. J. Bot. 26: 433-439. Krishnan, M S 1969. Geology of India and Burma. Hig- ginbothams, Madras. Lakhanpal. R N , AND M N Rose 1951. Some Tertiary leaves and fruits of the Guttifereae from Rajastan. J. Indian Bot. Soc. 30; 132-136. Lawrence, G. H. M 1951. Taxonomy of vascular plants. Macmillan Co., New York. Mahabale.T S , andJ V Deshpande 1957. The genus Sonneratia and its fossil allies. Palaeobotanist 6: 51-63. Maheswari, P 1950, An introduction to the embryology of angiosperms, McGraw-Hill Book Co., New York. Malcolmson, J. C. 1837. On the fossils of the Great Basaltic District of India. Trans. Geol. Soc. Lon- don 5: 537. Nambudiri, E M V 1969. A new specimen oUndocarpa Jain from the Deccan Intertrappean beds of Mo- hgaon Kalan. Proc. 56th Indian Sci. Congr., Bom- bay; 443. Ramanujam, C G. K. 1960. Silicified woods from the Tertiary rocks of South India. Palaeontographica 106B: 99-140. Rao, S R N , and K S. Rao 1935. The age of the Deccan Intertrappean beds near Rajamundrv. Curr, Sci, 4; 324. Rode, K P 1933. A note on fossil angiospermous fruits from the Deccan Intertrappean beds of Central Provinces. Curr. Sci. 2; 171-172. Sahni, B 1937, The age of the Deccan Trap. Proc. 24th Indian Sci. Congress, Hyderabad: 464-468. 1943. Indian silicified plants, 2. Enigmocarpon parijai, a silicified fruit from the Deccan, with a review of the fossil history of the Lythraceae. Proc. Indian Acad. Sci. 17: 59-^96. SCLATER, J G , AND R L FiSHER 1974. Evolution of the east-central Indian Ocean with emphasis on the tectonic setting of the Ninety East Ridge. Geol. Soc. Amer. Bull. 85: 683-702. Shallom, L. J 1960, Fossil dicotyledonous wood of Lecythidaceae from the Deccan Intertrappean beds of Mahurzari, J. Indian Bot. Soc. 39: 198-203. Sporne, K R 1974, The morphology of angiosperms. Hutchinson University Library, London. Takhtajan, a 1969, Flowering plants, origin and disper- sal, Oliver Boyd, Edinburgh. Van der Pijl, L 1955. Sarcotesta, aril, pulpa, and the evolution of angiosperm fruit. I and II. Kon Ned- erl. Adad. Wetenshap, Amsterdam 58: 154-161, 307-312. Vaughan.J.G, andJ M. Whitehouse. 1971. Seed struc- ture and the taxonomy of the Crucifereae. Bot. J. Linn. Soc. 64: 383-409. Venkatesvvarulu, J 1952, Embryological studies in Lecythidaceae. 1. J. Indian Bot. Soc. 31; 103-116. Verma, R. K , andG Pulliah 1967. Paleomagnetism of Tirupati sandstones from Godavari Valley, India. Earth and Planet Sci. Letters 2; 310-316. Wadia, D N 1966, Geology of India, Macmillan Co., Ltd. MATERNAL CARE OF NEONATES IN THE PRAIRIE SKINK, EUMECES SEPTENTRIONALIS Louis A. Somnia Abstract. — Maternal care of neonates has been documented in relatively few species of lizards representing four families. This study documents the occurrence of maternal care of neonates in the prairie skink, Emneces septentrion- alis. Observations made herein indicate that individual variation in maternal behavior exists in this species. Maternal care of neonates has been docu- mented in relatively few species of lizards. Parental protection of neonates and assistance during parturition or hatching, however, does occur in some lizard species in the families Gekkonidae (Robb 1986), Anguidae (Guillette and Hotton 1986), Scincidae (Tanner 1943, 1957, Evans 1959, Rose 1962, Hikida 1981, Slavens 1983, Hammond 1985, MehaflFey 1986), and Xantusidae (Cowles 1944). Initial observations on maternal care in Eumeces septentrionalis have been made by Somma (1985). The observations presented herein represent a more detailed description of ma- ternal care of neonates by E. septentrionalis. Five gravid females were obtained from Douglas County, Nebraska, during May 1984 and placed in separate plastic terraria with a soil substrate. A 14L:10D photoperiod was maintained for the duration of the study. Each terrarium contained a 15 x 15-cm plate of transparent, red acrylic under which the skinks could brood their eggs and be ob- served. Lizards were fed mealworms and crickets ad libitum. Eggs were oviposited be- tween 18 and 30 June and brooded until hatchling emergence (14-23 July). The type of maternal behavior expressed toward neonates was highly variable, al- though no attempt was made to quantify it. One female did not express any behav- ior toward its single surviving hatchling. Two females nudged their young while they emerged and then groomed them by licking the embryonic fluids from their bodies. These and two others each constructed small bur- rows extending 5-7 cm from their nest cavi- ties during hatchling emergence. Most of the neonates remained in these burrows with the adults for two days. All four adults followed their young around the nests while constantly directing tongue-flicks toward them. One fe- male remained tightly coiled around its neonates at all times. These maternal behav- iors lasted for two days before the adult skinks ignored their neonates and left their nests. At this time, both adults and neonates made at- tempts to escape their respective terraria. The maternal behaviors of the skinks ob- served in this study were not as pronounced as those reported earlier for this species (Somma 1985). In that study, the females remained with the hatchlings for three days and at- tempted aggressively to defend their young. The results of past and present observations on maternal behavior in Eumeces septentrion- alis indicate that much variation exists. Fur- ther studies are required to evaluate the sig- nificance of this behavior. Acknowledgments These observations were part of a master's thesis presented to the Department of Biol- ogy, University of Nebraska at Omaha. This department provided funds for the study. I thank J. D. Fawcett, M. Cherney, F. Kock, J. O'Hare, R. Vaughn, and S. Wurster for assist- ing me with this study. Literature Cited Cowles, R B 1944. Parturition in the yucca night lizard. Copeia 1944; 98-100. 'Department of Biolog\', University of Nebraska at Omaha, Omaha, Nebraska 68182. Present address: Department of Zoology, University of Florida, Gainesville, Florida .3261 1 536 October 1987 SoMMA: Skink Maternal Care 537 Evans, L. T 1959. A motion picture study of maternal behavior of the lizard, Ettmcces ohsolctus Baird & Girard. Copeia 1959: 103- 110. GuiLLEiTE, L J , Jr , AND N HoTiON III 1986. The evolu- tion of mammalian reproductive characteristics in tlierapsid reptiles. Pages 239-250 in N. Hotton III, P. D, MacLean, J. J. Roth, and E. C. Roth, eds.. The ecology and biology of mammal-like reptiles. Smithsonian Institution Press, Washing- ton and London. Hammond, S. 1985. Reproductive behavior in the broad- head skink, Einneceslaticeps. Notes NOAH 12(4): 7-8. HiKlDA.T 1981. Reproduction in the Japanese skink (Eh- ineces latisciitatus) in Kvoto. Zool. Mag. 90: 85-95. Mehaffey, D T 1986. Notes on captive propagation of the Solomon Island lizard Conicia zchrata at the Fort Worth Zoo. Gainesville Herpetol. Soc. News!. 2(4): 12-15. RoBB. J 1986. New Zealand amphibians and reptiles in colour. Collins, Aukland. Rose, W 1962. The reptiles and amphibians of southern Africa. Maskew Miller, Cape Town, South Africa. Slav ENS, F L 1983. Inventory of live reptiles and am- phibians in captivity, current January 1, 1983. Frank L. Slavens, Seattle. SoMMA, L A 1985. Notes on maternal behavior and post- brooding aggression in the prairie skink, Eumeces septoitrioiialis. Nebraska Herpetol. News). 6(4): 9-12. Tanner, W. W. 1943. Notes on the life history oi' Eumeces shiltonianus skiltDuianus. Great Basin Nat. 4(3-4): 81-88. 1957. A ta\onomic and ecological study of the western skink (Eumeces skiltunianus). Great Basin Nat. 17(3-4): 59-94. THERMAL TOLERANCES AND PREFERENCES OF FISHES OF THE VIRGIN RIVER SYSTEM (UTAH, ARIZONA, NEVADA) James E. Deacon', Paul B. Schumann", and Edward L. Stuenkel Abstract — Critical thermal maxima (CTM) and thermal preferenda of the common fishes of the Virgin River were examined. Differences in final temperature preferenda and CTM for species with low thermal lability (speckled dace, spinedace, roundtail chub) correspond well with differences in their distribution and abundance in the river. These species shifted their acute thermal preferences relatively little as acclimation temperature increased. For thermally labile species (woundfin, red shiner, desert sucker, and ilannelmouth sucker), the final preferendum is a less precise indicator of probable distribution. The woundfin, an endangered fish, has a high CTM (39.5 C at 25 C acclimation) and a labile acute preferendum (slope nearest 1) compared to other species in the system. The introduced red shiner likewise has a high CTM and a labile acute preferendum. In cooler temperatures, its acute preferendum shifts more rapidly than does that of the woundfin. At higher temperatures (above 15 C), the red shiner does not shift its acute preferendum as rapidly as does the woundfin. The red shiner, however, has a higher final preferendum. For thermally labile species, influence of acclimation temperature on mean preferendum, together with CTM, provides a better insight into distributional relationships within the system. In recent years, agricultural, municipal, and industrial water uses in arid regions of the southwestern United States have reduced both stream flows and water quality. The con- sequent alterations in thermal, chemical, and flow regimes, coupled with the discharge of various effluents and the introduction of non- native fishes, have seriously reduced many native fish stocks (Deacon and Minckley 1974, Deacon 1979, Pister 1979, 1981). The Virgin River in Utah, Arizona, and Ne- vada is an example of such a system. Its shift- ing, sandy bottoms, steep gradients, high sed- iment loads, variable flows, large daily and seasonal fluctuations in temperature, and other physical and chemical characteristics are typical of desert streams (Cook 1960, Dea- con and Minckley 1974, Naiman 1981). Below Zion National Park, Utah, several natural physicochemical and geographic barriers dis- rupt the continuity of the biotic communities. These include Pah Tempe Springs, a series of over 100 saline hot springs emerging along the Hurricane Fault in Utah; and the Virgin River Gorge in Arizona where, during much of the year, the entire flow seeps below ground and reemerges in springs above Littlefield, Ari- zona (Sandberg and Sultz 1982). The fish fauna of the Virgin River consists of only six native species: speckled dace (Rhi- nichthys osculus); flannelmouth sucker {Cato- stomus latipinnis); desert sucker (Cato- stomus [Pantosteus] clarki); Virgin spinedace (Lepidonieda mollispinis mollispinis ) and Vir- gin roundtail chub (Gila robusta seminuda), the latter two of which are endemic subspe- cies; and woundfin {Plagopterus argentis- simus), which is an endemic species. The woundfin is listed as endangered (U.S. Fish and Wildlife Service 1986), the Virgin round- tail has been recommended for endangered status, and the Virgin spinedace has been rec- ommended for threatened status (Deacon 1979, Deacon et al. 1979). The red shiner, Notropis lutrensis, was introduced into the Colorado River system as a bait fish in the early 1950s (Hubbs 1954). Of the 13 intro- duced fish species recorded from the lower Virgin River (Cross 1985), only the red shiner has become well established (Williams 1977, Cross 1978a). Agricultural diversion and groundwater use since 1900 have reduced flows in the main- stream to the extent that long stretches may be dry during summer months. Following completion of the Quail Creek Reservoir pro- ject early in 1985, an unanticipated, dramatic increase in discharge of Pah Tempe Springs 'Department of Biological Sciences, University of Nevada at Las Vegas, Las Vegas, Nevada 89154. ^Environmental Science and Engineering Program, University of California School of Public Health, Los Angeles, Los Angeles, California 90024. Present address: Office of Waste Programs Enforcement, U.S. Environmental Protection Agency, Washington, DC, 20460. ^Department of Physics, University of California, San Francisco, School of Medicine, San Francisco, California 94117. 538 October 1987 Deacon et al. : Virgin River Fish 539 caused increases in both temperature and salinity throughout the downstream segment of the Virgin River in Utah (Deacon, in press). Summer river temperatures fluctuate by 15-20 C daily, reaching 36 C in some areas (Cross 1975, Deacon 1977, Schumann 1978). However, except for the roundtail (Schumann 1978) and Virgin spinedace (Espinosa and Deacon 1978), the temperature responses of the native fishes have not been examined. This paper reports preliminary investiga- tions of the temperature tolerances and pref- erences of the native fishes and the intro- duced red shiner. Methods and Materials Collection and Maintenance of Specimens Suckers, spinedace, speckled dace, wound- fin, and red shiners were collected during May and June using 10-m nylon seines with 6.4-mm mesh. Virgin roundtail adults were collected between April and October. Cap- tured fish were acclimated in aerated and fil- tered 450-liter and 1100-liter aquaria, con- taining aged tap water maintained at temperatures of 10, 15, and 25 ± 1 C, for at least two weeks before testing (Otto 1973, Feldmeth and Baskin 1976, Otto and Rice 1977). Fish were maintained on a 12-hour photoperiod and fed Purina Trout Chow daily. Food was withheld for 25 hours prior to experimentation. All experiments were con- ducted between June and August to avoid the influences of seasonality and aging (McCauley et al. 1977). Critical Thermal Limits Tolerance of high temperature was mea- sured as critical thermal maximum (CTM) (Lowe and Heath 1969, Fry 1971, Feldmeth and Baskin 1976). The CTM was determined for six individuals of each species at each accli- mation temperature in an aerated 13-liter glass chamber immersed in a Masterline 2095 water bath. Fish were introduced into the chamber at their acclimation temperature. Af- ter a 60-minute adjustment period, the cham- ber was heated at a constant rate of 0.24 C/ minute until the animal lost equilibrium. At that point the fish was immediately returned to its acclimation temperature. No more than three fish were used in a single test. The temperature at which loss of equilibrium is observed is an unambiguous endpoint, eco- logically equivalent to death in a natural situa- tion where the animal would then be unable to escape lethal conditions (Fry 1971). CTMs were not measured for 15-C-acclimated suck- ers of either species (see next section). Thermal Preferendum Acute preferred temperatures (Reynolds and Casterlin 1979) were determined for six individuals of each species (except the suckers and the roundtail chub) at all acclimation tem- peratures. Testing was done in a horizontal gradient consisting of three 20-liter aquaria joined lengthwise and partitioned to give six small chambers, each 16 X 20 x 21 cm. One end was cooled by plastic-coated copper coils through which refrigerated water was circu- lated, while the other end was heated with 100-W aquarium heaters. Aeration in each cell prevented gas supersaturation and tem- perature stratification. Fish could thus choose temperatures between approximately 8 C and 35 C. Tests were observed from behind a blind, and temperatures were measured by mercury thermometers in each chamber. Preliminary tests without a thermal gradi- ent demonstrated that selection was not spa- tially influenced in any of the species. This was further avoided during the course of the experiments by a slight shift of temperatures along the gradient. Two or three individuals of a single species were introduced into the chamber closest to their acclimation temperature and left undis- turbed for 30 minutes. Chamber tempera- tures and the distribution of the animals in the gradient were then recorded at 10-minute in- tervals for one hour, and at 20-minute inter- vals for the next two hours. The fish were then removed and their length and weight recorded (Table 1). Time and resource constraints prevented our collecting enough suckers (of either spe- cies) to provide complete acclimation groups. Therefore, preferenda are reported for fewer than six individuals at most acclimation tem- peratures (Table 2). Likewise, insufficient numbers of Virgin roundtail adults small enough to fit the apparatus were available at the time of the tests. Consequently, young-of- the-year roundtails spawned in captivity from adults captured from the nearby Moapa River in Nevada were acclimated to 8 C, 22 C, 25 C, 540 Great Basin Naturalist Vol. 47, No. 4 Table 1. Critical thermal maxima (CTM) at three acclimation temperatures for the common fishes of the Virgin River. Each number is the mean ± 1 standard deviation for six fish, except that only three desert suckers were used at 25 C and three flannelmouth at 10 C. A range in length is shown for roundtail. Species T,,,,(°C) Length (mm) 10 15 25 Weight (gr. ) Roundtail chub 27.90 ± 0.22 32.30 ± 1.39 36.41 ± 0.66 120 - 233 62.60 ± 47.60 Speckled dace 30.47 ± 1.60 32.57 ± 0.46 36.82 ± 0.63 72.17 ± 12.70 3.73 ± 1.86 Virgin spinedace 30.25 ± 0.40 32.90 ± 0.30 37.02 ± 0.44 95.79 ± 7.66 8.54 ± 1.99 Woundfin 30.70 ±0.21 33.58 ±1.01 39.47 ± 0.21 71.27 ± 10.56 3.35 ± 1.35 Red shiner 30.10 ± 1.05 33.07 ± 0.59 38.80 ± 0.71 61.47 ± 6.43 2.92 ± 1.06 Desert sucker 32.30 ± 0.64 — 37.17 ± 0.50 124.60 ± 22.89 16.35 ± 7.33 Flannelmouth sucker 31.22 ± 1.08 — 36.98 ± 0,29 1.55.60 ± 20.94 27.57 ± 9.48 Table 2. Distribution of native and introduced fishes of Virgin River in a thermal gradient. Fish were accliinaled to 10, 15, and 25 C. Data for the Virgin roundtail are in Schumann (1978). Species Temperature Accl. temp. fish # obs Max. Min. Mean Mode Speckled dace Virgin spinedace Woundfin Red shiner Desert sucker Flannelmouth sucker 10 6 77 20 15 6 78 26 25 6 71 27 10 6 68 26 15 7 86 31 25 6 78 29 10 6 78 20 15 6 69 23 25 6 72 32 10 6 78 22 15 6 50 31 25 6 75 34 10 6 80 28 25 3 36 30 10 3 46 25 25 6 65 34 10 14 9 10 15 15 10 14 13 10 15 10 10 10 10 15 14 4.4 9.5 - 10.5 16 2.8 14 - 15 16 4.2 15 - 16 19 3.8 18.5 - 19.5 21 3.7 21.5 - 22.5 23 3.4 24 - 25 11 2.3 10 - 11 16 3.6 14 - 15 24 4.8 23.5 - 24.5 12 3.8 10 - 11 23 4.9 23 - 24 27 5.0 30 - 31 13 4.3 10 - 11 22 3.5 20 - 21 14 5.0 10 - 11 26 2.8 26 - 27 and 30 C and tested in the same manner as the other species (Schumann 1978). As with the 15-C-acchmated suckers, resuhs were not compared statistically with the other fish but are presented here to complete the picture for the native species. Analysis of Data CTM data were analyzed by Welch's un- equal-variance analysis of variance (ANOVA) and Bonferroni paired comparisons. Regres- sion lines for CTMs were constructed and compared by covariance analysis (Dixon 1981). Significance of temperature selection was verified by chi-square tests for each species. Differences between species and between acclimation temperatures were tested by Welch's unequal-variance ANOVA and Bon- ferroni paired comparisons (Dixon 1981). These were verified by two-way ANOVA (Burr 1974) and two-way Friedman's test (Tate and Clelland 1957) of the means for each group. Nonlinearity of preference curves was verified by regression analysis (Dixon 1981). Results Temperature Tolerance CTM increased in a linear fashion with ac- climation temperature for all species exam- ined. Within any given species, mean CTM values differed significantly (p < .05) at differ- ent acclimation temperatures (Table 1). CTMs were not significantly different (p > .05) between species in either the 10-C- or October 1987 Deacon et al. : Virgin River Fish 541 15 20 25 Taccl. (°C) 30 Fig. 1. The effect of acclimation temperature on critical thermal maximum in three Virgin River fishes. Regres- sion lines are presented for one representative species of each group described in the text. 15-C-acclimation groups. However, at 25 C acclimation, the mean CTMs of woundfin and red shiner each differed significantly from all other species (p < .05), although they were not significantly different from each other (p>.05). The lines relating CTM to acclimation tem- perature have slopes ranging from 0.28 (desert sucker) to 0.59 (woundfin). These are illustrated in Figure 1 along with that of the speckled dace, which is intermediate at 0.42. The flannelmouth sucker (0.38), Virgin spinedace (0.45), Virgin roundtail (0.48), and red shiner (0.58) also fall between the ex- tremes. An increase in slope indicates that acclimation temperature has an increased ef- fect on CTM. Thermal Preference The frequency distribution of each species in the thermal gradient (Table 2) suggests that variation and skewness were associated with some experimental groups (Richards et al. 1977). For any given species, the mean acute preferred temperature observed at one accli- mation temperature differed significantly at the .05 level from the mean preferendum at any other acclimation temperature, with one exception: no significant difference (p > .05) was found between acute preferenda of 15-C- and 25-C-acclimated speckled dace. In all other cases, an increase in acclimation tem- perature shifted thermal preferenda upward (Figs. 2 and 3). Mean acute preferenda equaled or exceeded acclimation temperature for all species acclimated to 10 C and 15 C. At 25 C acclimation, however, this was true only for the flannelmouth sucker and the red shiner. Modal preferred temperatures like- wise equaled or exceeded temperature of ac- climation for all species acclimated to 10 C and for all species except woundfin at the 15-C-acclimation level. As was found for the means, modal preferenda in the 25- C-acclimation group were greater than or equal to acclimation temperature for only flannelmouth suckers and red shiners. Discussion Despite the large body of information on the physiological performance of organisms with respect to temperature, surprisingly few studies relate this clearly to the organism's ecology (Ferguson 1958, Gift 1977, Richards and Ibara 1978, Huey and Stevenson 1979, Reitinger and Fitzpatrick 1979, Calhoun et al. 1982, Matthews 1986). Only recently have formalized attempts been made to define a "thermal niche" for ectotherms and to apply concepts of niche theory and competition to the thermal resource (Fry 1971, Alderdice 1972, Hutchinson 1978, Magnuson et al. 1979). The Virgin River's considerable spatial and temporal variation in water temperature places greater value on eurythermal species that can operate as "thermal generalists" un- der suboptimal conditions, but respond op- portunistically when preferred thermal situa- tions are encountered. This is the established pattern for desert spring and stream fishes for such factors as food and space (Deacon and Minckley 1974). Magnuson et al. 1979 state that lethal tem- peratures are so extreme as to say little about the "fine tuning" of an organism's utilization of its thermal resource. However, these set the outermost limits of the thermal niche and form the bounds of the thermal resistance zone (Reynolds and Casterlin 1979). Our CTM values (Table 1) illustrate the eury- thermality of these desert species. This is shown further by the ranges associated with the acute thermal preferences (Table 2). We recorded observations between 10 C and 542 Great Basin Naturalist Vol. 47, No. 4 30- Final preferendum 23.8 ± 0.5 Roundtail 23.1 ± 0.5 Spinedace 15.8 ± 0.2 Speckled dace 10 15 20 25 30 ACCLIMATION TEMPERATURE (°C) Fig. 2. Influence of acclimation temperature on mean preferred temperature in Virgin River fishes of low thermal lability. Lines fitted by eye. 32-34 C for all species except the desert sucker and speckled dace. Further, when Magnuson et al.'s (1979) operational defini- tion of thermal niche breadth (i.e., mean pre- ferred temperature ± one standard devia- tion) is applied to Figure 2, all species exhibit ranges 5-10 C in breadth at all acclimation temperatures. This implies that desert fishes tend to have broader thermal niches than most temperate freshwater fishes previously considered (Reutter and Herdendorf 1974, Beitinger et al. 1975, Coutant 1977, Magnu- son et al. 1979). Nearly all species tested exhibited skewed preferred temperature distributions (Table 2). This resulted in differences between the various measurements of central tendency used to describe them. The skewed patterns may be partly attributable to the design of the apparatus, but similar findings have been re- ported by De Witt (1967), Reynolds and Cast- erlin (1976, 1979), and others using a variety of designs. This widespread phenomenon and its possible causes and effects have been re- viewed in detail by De Witt and Friedman (1979). Fry (1947) defined the final thermal prefer- endum, in part, as being the point where preferred temperature equals acclimation temperature. He considered this a largely species-specific phenomenon, independent of the animal's previous thermal history. This concept has garnered considerable attention in recent years, although, surprisingly, its po- tential for bridging the gap between thermal physiology and ecology has remained rela- tively unexplored (Reynolds 1977). The results of our attempts to define the final thermal preferendum of the Virgin River fishes are shown in Figures 2 and 3. Each curve was fitted by eye to the mean acute preferendum values according to the method of Reynolds and Casterlin (1979) (see also Otto and Rice 1977, Garside et al. 1977, Richards and Ibara 1978). This gave approximate final preferenda of 27.0 C for the red shiner, 25.9 G for the flannelmouth sucker, 23.8 G for the roundtail, 23. 1 G for the spinedace, 19.5 G for October 1987 Deacon etal; Virgin River Fish 543 Fina preferendum 27.0 ± 1.0 Red shiner 25.9 ± 0.5 Flannelmouth sucker 17.5 ± 1.0 Woundfin 19.5 ± 1.0 Desert sucker 30 ACCLIMATION TEMPERATURE ( °C) Fig. 3. Influence of acclimation temperature on mean preferred temperature in thermally labile Virgin River fishes. Dashed curves are hypothesized from responses of a single 15-C-acclimated specimen (see text). Lines fitted by eye. the woundfin, 17.5 C for the desert sucker, and 15.8 C for the speckled dace. Final prefer- enda of 30.0 and 23.3 C have been deter- mined for populations of red shiner in two distinctly different habitats in Texas (Calhoun et al. 1982). Three types of curves are represented in Figures 2 and 3. The curves most closely ap- proximating the hne of equality (Fig. 3) indi- cate a maximally thermally labile species. This situation, represented most strongly by the woundfin, suggests that the species prefers the temperature in which it finds itself This may be adaptive for a fish subjected to widely varying thermal conditions. As long as it can acclimatize successfully to ambient condi- tions, it probably operates near peak physio- logical efficiency throughout much of the range of seasonal variation encountered (Beitinger and Fitzpatrick 1979). The curves diverging most strongly from the line of equal- ity (Fig. 2) characterize species whose pre- ferred temperature remains nearly un- changed despite wide variations in acclima- tion temperature (Brett 1952, McCauley et al. 1977). The curves for the red shiner and flan- nelmouth sucker (Fig. 3) differ from both of the above two types. At cooler temperatures, rising accfimation temperatures shift prefer- enda upward rapidly, while at warmer tem- peratures, acclimation temperature has rela- tively little influence on preferred temperature. These three apparently differ- ent types of curves provide interesting insight into the ecology and distribution of fishes in the Virgin River. The woundfin has a high CTM, relatively low final preferendum, and the most labile acute preferendum of any of the species exam- ined. It is the dominant native species in the moderately altered sections of the middle and lower mainstream where temperature vari- ability is extreme (Cross 1978a, Deacon and Hardy 1984). The thermal lability of the 544 Great Basin Naturalist Vol. 47, No. 4 woundfin is most strikingly demonstrated by the ability of acclimation temperature to influ- ence preferred temperature. This capability, however, becomes somewhat reduced at higher temperatures as the thermal selection curve diverges from the line of equality (Fig. 3). At higher temperatures, then, the red shiner may have an advantage over woundfin, while at lower temperatures (below 25 C), the reverse may occur. The thermal selection curve for the desert sucker suggests that it, too, is thermally labile. It diverges more from the line of equal- ity at both higher and lower temperatures than does the woundfin; however, the final preferendum is also somewhat lower, sug- gesting a more upstream (cooler) pattern of distribution and abundance than woundfin. The desert sucker is in fact the most widely distributed species in the Virgin River sys- tem, reaching greatest abundance in middle and lower tributaries and the upper main- stream. Abundance drops in the lower, warmer mainstream and in the upper, cooler tributaries (Cross 1975, 1985). The thermal selection curves of the other native species are uniformly similar in shape, differing primarily in vertical displacement. All appear less labile than the woundfin and desert sucker. The speckled dace, with the lowest final preferendum, has the most up- stream distribution. It achieves greatest abundance in middle and lower tributaries and the upper mainstream. In the middle and lower mainstream it is almost always associ- ated with cool, clear inflowing tributaries or springs. The Virgin spinedace, with the next highest final preferendum, has a slightly more downstream distribution. It is most abundant in lower tributaries and the upper main- stream. More downstream occurrences are primarily associated with tributary and spring inflows. The flannelmouth sucker has the highest final preferendum, but reaches its greatest abundance in the upper mainstream. Its downstream distribution, however, is not as restricted to tributary and spring inflow as are those of the speckled dace and spinedace. In general, the distributional relationships of these three species (Cross 1975) correspond well with the thermal relationships illustrated in Figures 2 and 3. Note also that the flannel- mouth sucker (which had the highest final preferendum of any native species) and the woundfin (with the highest CTM) most often approach the Pah Tempe hot spring inflows more closely than other species (Cross 1975, Williams 1977). The Virgin roundtail has a thermal selection curve very similar to that of the spinedace. It has the lowest CTM value of any native spe- cies in the river and an intermediate final preferendum. Acclimation temperature has relatively little influence on its preferred tem- perature. This species is confined to the mid- dle and lower mainstream of the Virgin River below Pah Tempe Springs (Cross 1978b). The roundtail is no longer perennially abundant anywhere within its range, although there is evidence that it once was (Cross 1978b). In- creased diversion of water for irrigation, in- creased irrigation return flow in the heat of the summer, clearing of streamside vegeta- tion, overgrazing in the watershed, and other activities associated with man's use of the re- gion may have increased summer tempera- tures within the range of the roundtail. Lack of suitable tributary streams, plus the barrier provided by Pah Tempe Springs, has perhaps prevented upstream displacement of round- tail populations. Their thermal relationships suggest a pattern of distribution and abun- dance in the Virgin River similar to that of the spinedace. The fact that most good spinedace habitat is unavailable to the roundtail may partly explain its present precarious status in the Virgin River. The thermal selection curves for the red shiner and flannelmouth sucker are different from those of other native species. The red shiner has a high CTM, and a higher final preferendum than any native species. It oc- curs throughout the lower mainstream but, until 1985, was abundant only in the deeper water (> 8 cm) of the highly modified lower reach, where the flow is intermittent through a wide, shallow, braided channel. Here, sum- mer temperatures appear to exceed 30 C more often, and for longer periods, than else- where in the river. The red shiner is the domi- nant species in this segment of the river and is often accompanied by fewer numbers of woundfin. Other native species occur sporadi- cally. Occasionally woundfin reach numbers nearly equaling those of the red shiner (Cross 1975, Deacon and Hardy 1984, Deacon, in press). Woundfin and red shiner shift their CTM October 1987 Deacon et al. : Virgin River Fish 545 more markedly in response to increase in ac- climation temperature than do other species. This apparently provides both species with an advantage over other native fishes in the warmer, more thermally variable, shallow wa- ters of the lower river. The higher final prefer- endum exhibited by the red shiner suggests that that species may have a thermal advan- tage over the woundfin during the summer in this lower segment of the mainstream. The flannelmouth sucker has only a slightly lower final preferendum than does the red shiner, but at an acclimation temperature of 25 C the sucker has a significantly lower CTM. This may partly explain the near absence of the flannelmouth sucker in Virgin River be- low Mesquite, Nevada. Thermal tolerance and preference relation- ships are not the only factors involved in niche partitioning in the Virgin River. Preferred temperatures may be unavailable over large stretches of the river, or for long periods of time. Interactions influencing utilization of food, space, and other resources affect the fishes as well (Cross 1975, 1978a, 1978b, Dea- con 1979, Deacon and Hardy 1983, Greger 1983). Temperature relations determined in the laboratory do not always correspond well to field distributions (Reynolds 1977, Magnu- son et al. 1979, Reynolds and Casterlin 1979), but in the case of the Virgin River fishes, the correspondence is striking. Acknowledgments Assistance of the following individuals is gratefully acknowledged: Dr. S. D. Hillyard of UNLV and M. B. Marrero of the University of Texas at Dallas for their generous help in collection of specimens, and Dr. Hillyard for helpful comments and criticism of the manuscript. We especially thank V. M. J. Ryden of the Southern California Association of Governments for aid in statistical analysis. Partial funding for this project was provided by the U.S. Fish and Wildlife Service. The manuscript was largely completed while J. E. Deacon was a Barrick Distinguished Scholar at UNLV. Literature Cited Alderdice. D F 1972. Responses of marine poikilo- thernis to environmental factors acting in concert. Pages 1659-1722 in O. Kinne, ed.. 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Zool. 19; 211- 224. Richards, F P , and R M Ibara 1978. The preferred temperatures of the brown bullhead, Ictalurus nebidosus, with reference to its orientation to the discharge canal of a nuclear power plant. Trans. Amer. Fish. Soc. 107; 288-294. Richards, F P . W W Reynolds, R W McCauley, L 1 Crawshaw, C C Coutant, and J J. Gift 1977. Temperature preference studies in environmental impact assessments: an overview with procedural recommendations. J. Fish. Res. Bd. Canada 34: 728-761. Sandberg, G W, and L G Sultz 1985. Reconnaissance of the quality of surface water in the upper Virgin River Basin, Utah, Arizona, and' Nevada, 1981-82. Utah Department of Natural Resources Technical Publication No. 83; 1-69. Schumann, P B 1978. Responses to temperature and dissolved oxygen in the roundtail chub, Gila ro- busta Baird & Girard. Unpublished thesis. Uni- versity of Nevada at Las Vegas. Tate, M W , and R C Clelland 1957. Nonparametric and shortcut statistics in the social, behavioral, and medical sciences. Interstate Printers and Pub- lishers, Danville, Illinois. US Fish AND Wildlife Service 1986. Endangered and threatened wildlife and plants, January 1, 1986. Pages 1-30. Williams, J E. 1977. Adaptive responses of woundfin, Plagopterus argentissitnus, and red shiner, Notropis lutrensis, to a salt spring and their proba- ble effects on competition. Unpublished thesis. University of Nevada at Las Vegas. SIX NEW SCOLYTIDAE (COLEOPTERA) FROM MEXICO Stephen L. Wood' Abstract. — Alniphagus africanus Schedl, 1963, and Hylesinits ufricanus Schedl, 1965, were both transferred to Htjlesinopsis and thereby become junior homonyms of//, africanus (Ep;gers, 1933). The new name H. acacicolens is proposed as a replacement for Schedl's 1963 name and //. secuttis as a new name for Schedls 1965 name. Six species from Mexico are described as new to science, inchiding; Hylociirtis atkinsoni, H. crotonis, Monarthrum xalapensis, Pseudochramesus jaliscoensis , Pseudopittjophthorus duranguensis. and P. xalapae. On the following pages two junior homonyms are renamed in the African genus Htjlesinopsis, and six species new to science are described from Mexico. The new species represent the genera Hylocunis (2), Monar- thrum (1), Pseudochrarnesiis (1), and Pseiido- pityophthorus (2). This is the first record of the genus Pseudochrarnesiis north of Bolivia and Brazil. Hylesinopsis acacicolens, n. n. Alniphagus africanus Schedl, 1963, Ent. Abh. Mus. Tierk. Dresden 28:259 (Holotype, sex?; Riff Val- ley, Kenya; Wien Nat. Mus.) The species named by Schedl (1963:259) as Aniphagus africanus is here transferred to the genus Hylesinopsis. This transfer makes it a junior homonym of H. africanus (Eggers 1933:19) that was originally named in Pseu- dophloeotribus, transferred to Metahylesinus by Schedl (1957:9), then to Hylesinopsis (Wood 1986:39). The new name acaciocolens is proposed as a replacement for africanus Schedl 1963. The genus Alniphagus occurs only on the northern Pacific Coast from Japan to Califor- nia and is quite unrelated to the African fauna. Hylesinopsis secutus, n. n. Hylesinus africanus Schedl, 1965, Novos Taxa Ent. 38;4 (Holotype, female; Uganda, Mpanga; British Mu- seum [Natural History]). The species named as Hylesinus africanus Schedl (1965:4) is here transferred to Hylesinopsis. This transfer makes it a junior homonym of H. africanus (Eggers 1933:19) that was originally named in Psetido- phloeotribus before it was transferred to Hylesinopsis (Wood 1986:39). The new name secutus is proposed as a replacement for africanus Schedl 1965. The genus Hylesinus is not known to occur in Africa south of the Sahara Desert. Hylocurus atkinsoni, n. sp. This species is distinguishesd from the closely allied prolatus Wood by the much smaller size, and by the more conservative sculpture of frons and elytral declivity of both sexes as described below. Male. — Length 1.7 mm (paratypes 1.8-2. 1 mm), 2.8 times as long as wide; color very dark brown. Frons similar to prolatus, modestly, trans- versely impressed below level of antennal in- sertion, moderately elevated above into an indefinite, transverse, subcarinate elevation; surface rather coarsely reticulate-granulate, with rather coarse, moderately close tuber- cles above; vestiture sparse, inconspicuous; antenna about as in prolatus. Pronotum outline as in prolatus; deeply reticulate on posterior half, a few small crenu- lations on median area to base. Vestiture evi- dent only at margins. Elytra less slender and apex more obtusely pointed than in prolatus; strial punctures slightly smaller, not as deep, interstriae smooth and impunctate except near declivity. Declivity not as abrupt or as steep as prolatus; sculpture resembling prolatus except tuber- cles on 1 and 3 continued to level of junction of 5 and 7, 4, 5, 6, and 7 with tubercles continu- ing to their apices; 9 elevated but less abrupt than in prolatus; apex strongly mucronate. Life Science Museum and Department of Zoology, Brigham Young University, Provo, Utah 84602 547 548 Great Basin Naturalist Vol. 47, No. 4 Vestiture restricted to interstriae at base of declivity, equal in abundance to prolatus, but much stouter, about half as long. Female. — Similar to male except frons with impression and elevation largely obso- lete, sculpture much finer, tubercles mostly obsolete, upper frons with a very few setae in median area (resembling prolatus but much less abundant); sculpture of pronotum and elytra much finer, declivity more evenly con- vex, tubercles much smaller, less conspicu- ous; declivital setae more slender. Type locality. — El Casillo, Veracruz, Mexico. Type material. — The male holotype, fe- male allotype, and two broken paratypes were taken at the type locality on 18-VII-1983, No. 9, Inga sp., by Felipe A. Noguera. One paratype bears the same locality and date. No. 3-917, Acacia pennatula, Atkinson and Equi- hua. Four paratypes are from Banderilla, Ver- acruz, Mexico, 24 Nov. 1983, No. 96, Leit- caena pulverulenta, Felipe A. Noguera. The holotype, allotype, and paratypes are in my collection. Hylocurus crotonis, sp. n. This species is distinguished from the allied incomptus Wood and nodulus Wood by the smaller size, much stouter male declivital se- tae, and by other characters described below. Male. — Length 1.8 mm (male paratype 1.8 mm), 2.6 times as long as wide; color black. Frons resembling incomptus except trans- verse carina longer, more definite, length more than two-thirds distance between eyes; surface finely rugose reticulate, granules and punctures not clearly evident; vestiture short, sparse, inconspicuous. Pronotvmi similar to incomptus except ante- rior margin armed by a row of six rather coarse serrations; posterior half more strongly rugose reticulate, tubercles closer, more sharply defined; setae coarser. Elytra about as in incomptus except strial and interstrial punctures more clearly im- pressed, those of interstriae almost as large as those of striae, becoming somewhat tubercu- late near declivity; declivital sculpture similar except transverse impression on lower half not as strong, all tubercles smaller; vestiture largely confined to declivital interstriae, longest equal in length to distance between rows, each very stout, about 8 times as long as wide, shorter on lower declivity toward su- ture. Type locality. — Estacion de Biologia, Chamela, Jalisco, Mexico. Type m.aterial. — The male holotype and one male paratvpe were taken at the type locaHty lO-X-1982, 100 m, S-817, from Croton pseudoniveus, hyT. H. Atkinson and A. Equi- hua. The holotype and paratype are in my collec- tion. Monar-tJirum xalapensis, n. sp. This species superficially resembles the scutellarc portion of this genus, but its true affinities lie with species allied to dimidiatum Ferrari. From dimidiatum it is distinguished by the conspicuously different elytra in both sexes, and by other minor details described below. Male. — Length 2.0 mm (paratypes 1.9-2.0 mm), 3.2 times as long as wide; color reddish brown. Frons broadly, evenly convex; surface finely reticulate, upper and lateral areas with shallow, rather small punctures except obso- lete on median half of lower half, this area appearing spongy but without any indication of microsetae. Antennal club subcircular, with two moderately procurved sutures marked by setae; funicle 2-segmented. Pronotum about as in dimidiatum. Elytral outline resembling dimidiatum ex- cept not tapered toward apex, disc more strongly reticulate, declivity more broadly, deeply excavated, sutural emargination equal. Lateral margin of declivity from base to emargination strongly, acutely elevated (con- siderably more so than in dimidiatum); mar- gin armed on upper fourth by a coarse, pointed denticle in position of striae 3, a sec- ond obtuse denticle of almost equal size di- rected somewhat mesad on lower third; no other irregularities on margin; floor of exca- vated area shining, weakly reticulate, with small, confused, moderately abundant punc- tures. Glabrous except for sparse setae on sides near declivity. Protibiae armed more coarsely than in dimidiatum on same pattern. Female. — Similar to male except frons punctured throughout, epistoma armed on margin by a small tubercle; declivity resem- bling female dimidiatum except lower area less broadly impressed, upper denticle October 1987 WooD: New American Scolytidae 549 similar, lower denticle obtuse, submammi- form, displaced mesad (as close as upper pair). Type LOCALiTi , — Jalapa, Veracruz, Mexico. Type material. — The male holotype, fe- male allotype, and six paratypes were taken at the type locality on 8-IX-1983, No. 53, by Filipe A. Noguera. The holotype, allotype, and paratypes are in my collection. Pseudochramesus jaliscoensis , n. sp. This is the first record oi Pseudochramesus north of Bolivia and Brazil. This species is allied to opacus Schedl, but is distinguished by the smaller size, by the less distinctly tu- berculate anterolateral areas of the pronotum, and by the very different male frons. Male. — Length 1.4 mm (paratypes 1.4- 1.5 mm), 1.4 times as long as wide; color black, some setae pale. Frons with antennal insertion near middle of longitudinal axis, their bases separated by half distance between eyes about as in opacus; median area less strongly sulcate than in opa- cus, slightly narrower, not as smooth, fine tubercles clearly evident particularly laterally and above, scrobelike impressions not as deep or as extensive; transverse epistomal eleva- tion not as high or as distinct as in opacus. Antenna about as in opacus. Pronotum similar to opacus, punctures smaller, much less distinct, tubercles on ante- rior half and lateral areas distinctly larger, more numerous. Elytra similar to opacus, striae apparently less strongly impressed and less strongly punctured, and crenulations on elytral bases appear narrower. Female. — Similar to male except frons broadly convex, antennal bases separated by same distance as eyes, fine tubercles present as in male. Type LOCALiri — Carretera Barra Navi- dad-Puerto Vallarta, Jalisco, Mexico. Type m.aterial. — The male holotype, fe- male allotype, and eight paratypes were taken at the type locality on 21-X-1985, No. 360, from Cynometra oaxacana, by T. H. Atkin- son. The holotype, allotype, and paratypes are in my collection. Pseudopityophthorus durangoensis , n. sp. This species is distinguished from tenuis Wood by the larger size, by the longer setae on the ventrolateral areas of the declivity, and by details of frontal sculpture and ornamenta- tion in both sexes. Male. — Length 1.5 mm (paratypes 1.4-1.7 mm), 3.0 times as long as wide; ma- ture color dark brown. Frons more broadly, more strongly im- pressed than in tenuis, setae slightly longer. Pronotum appearing more elongate than in tenuis and with punctures on posterior half more numerous and larger. Elytra as in tenuis except strial punctures more definite, both strial and interstrial setae distinctly longer, strial punctures on declivity minute, but more clearly identifiable. Female. — Similar to male except frons re- sembling female tenuis but less strongly im- pressed below, more strongly above, upper half coarsely irregular, almost aciculate, lower half with a rather strong median carina ex- tending almost to epistomal margin, setae longer, much more conspicuous. Type locality. — Ninety-six km (60 miles) west of Durango, Durango, Mexico. Type material. — The male holotype, fe- male allot\'pe, and 32 paratvpes were taken 5-VI-1965,' 2,300 m (7,000 ft). No. 30, from Quercus, by me. Three paratypes are labeled 3 miles W El Salto, Durango, Mexico, 7-VI- 1965, 7,500 ft. No. 41, Quercus, taken by me. One paratype is from 10 miles W El Salto, Durango, Mexico, July 1964, J. B. Thomas. The holotype, allotype, and paratypes are in my collection. Pseudopityophthorus xalapae, n. sp. This species is distinguished from duran- goensis by the differences in male and female frons as described below, by the more abun- dant, persistent setae on declivital interstriae 1 and 3, by the feeble granules on interstriae 2 near its apex, and by the larger average size. These populations are obviously closely allied and future collecting could discover intergra- dation between them. Male. — Length 1.7 mm (paratypes 1.7-1.8 mm), 2. 7 times as long as wide; color ver\' dark brown. 550 Great Basin Naturalist Vol. 47, No. 4 Frons resembling durangoensis except much more broadly flattened, almost smooth, finely, rather closely punctured; setae on lat- eral margin much more abundant, longer, dorsal setae more broadly distributed. Pronotum and elytral disc about as in durangoensis. Declivity with setae on inters- triae 1 and 3 more regularly, closely placed, interstriae 3 with lower punctures feebly granulate; setae on striae 1 and 2 minute but present (obsolete in durangoensis). Female. — Similar to male except frons dif- fering from female durangoensis by less strongly impressed, smoother dorsal area with a few rather coarse punctures, median carina stronger, separated from epistomal margin by half length of carina. Type locality. — Xalapa, Veracruz, Mex- ico. Type material. — The male holotype, fe- male allotype, and four paratypes were taken at the type locality on 10-VII-i983, No. 30, by Filipe A. Noguera. The holotype, allotype, and paratypes are in my collection. GENETIC VARIATION AND POPULATION STRUCTURE IN THE CLIFF CHIPMUNK, EUTAMIAS DORSALIS , IN THE GREAT BASIN OF WESTERN UTAH Martin L. Dobson', Clyde L. Pritchett-, and Jack W. Sites, Jr.^ Abstract — Allelic variation at 21 of 39 electrophoretically resolved enzyme loci was used to examine patterns of geographic differentiation and population structure in six allopatric samples of Eutamias dorsalis. Coefficients of genetic similarity for paired combinations of £. dorsalis samples ranged from 0.955 to 0.975, except for one population that was 0.900. Conservative genie divergence among five populations is proposed to be the result of relatively recent isolation events. High positive F,s values and chi-square analyses confirm a significant excess of homozygotes at several loci at the five localities for which sample sizes were statistically adequate. This may be partly attributable to inbreeding, a Wahlund effect, linkage disequilibrium, posttranslational modification, or some combination of these; but at present some of these alternatives cannot be excluded in favor of a single explanation. Some samples were collected across altitudinal gradients of over 800 m, suggesting that a Wahlund effect may be the most likely explanation for low levels of heterozygosity in these populations. The distribution of montane mammals in the Great Basin of western Utah is disjunct, with populations isolated by low-elevation, cold desert valleys (Brown 1971a). The ob- served pattern has been explained by Pleis- tocene retreat (Late glacial to Late pleniglacial) of montane elements from plu- vial valleys to higher elevation and more northern latitudes (Currey and James 1982, Wells 1983). At least four major glacial events occurred during the Pleistocene. The most recent, the Wisconsin, is suspected of having the greatest influence on existing boreal mam- mal faunas. Maximum glaciation occurred from the end of Early Pluvial (23,000 years B.P.) to Late Pluvial (12,500 years B.P.). Dur- ing this time coniferous forests covered the foothills and piedmont, while low-elevation areas not covered by Lake Bonneville were dominated by sagebrush and juniper commu- nities. Coniferous forests offered favorable dispersal habitat (Thompson and Mead 1982, Van Devender and King 1971, Wells and Berger 1967) in the intermountain valleys and low passes, which may have allowed exchange of montane faunal elements across the Great Basin. The onset of xeric conditions during the Late Pluvial (12,500-7500 years B.P.) ini- tiated major vegetation changes. Coniferous forests retreated upward in elevation and pinyon-juniper began to replace sagebrush communities from the south (Van Devender and Spaulding 1979). Continued warming during the Postpluvial (7,500-5,000 years B.P.) allowed range expansion of xeric mam- mal species in the low-elevation deserts, while ranges of small montane mammals fol- lowed vegetation shifts north and to montane uplands. Recent biogeographic theory (Brown 1971a, 1978, Patterson 1980, 1982) suggests that distributions of small mammals can be explained as nonequilibrium extinctions with- out recolonization. Thus, the Great Basin environment and its insular montane mammal faunas offer interesting evolutionary "experi- ments" in which to assess the effects of isola- tion and possible recent population bottle- necking on levels of genetic divergence among conspecific montane mammal popula- tions. The possibility of occasionally severe reductions in the sizes of insular mammal pop- ulations would be conducive to rapid fixation of alternate alleles and loss of overall genetic variability due to sampling error (Nei et al. 1975, Kilpatrick 1981), and this would facili- tate divergence between populations despite their very recent isolation. This study reports on levels of genetic variability within and among samples of cliff chipmunks {Eutamias dorsalis) from six isolated mountain ranges in 2437 Central Avenue. Cody. Wyoming 82414 Department of Zoology. Brigham Young University. Prove, Utah 84602. 551 552 Great Basin Naturalist Vol. 47, No. 4 Fig. 1. Collection localities for Eutamias dorsalis from six mountain ranges in western Utah. Locality abbrevia- tions are as in Table 1; stippled areas represent mountain ranges above 2,000 m; hatched region represents the Rockv Mountains. western Utah, in an attempt to evaluate the effects of drift and recent insularization. Materials and Methods A total of 90 specimens representing six allopatric populations oi Eutamias dorsalis in the Great Basin of western Utah (Fig. 1) was collected from May through September 1983. All 90 voucher specimens were deposited in the Brigham Young University mammal col- lection as standard museum mounts. Collec- tion location, population abbreviations and sample sizes, and voucher specimen numbers are presented in Table 1. Preferred habitat of cliff chipmunks is open canopy pinyon-juniper complex on granite substrate (Brown 1971b). Chipmunk densities were low in all sites except two: Indian Farm Canyon of the Deep Creek Mountains and Painter Creek of the House Range. Low den- sity in the Stansbury Range reflects the small area of suitable habitat. Two locations were sampled from both the House Range and the Deep Creek Mountains (Table 1, Fig. 1), but in each case specimens were assumed to be from one breeding population because of site proximity and habitat uniformity. Heart, liver, and blood tissues were immediately re- moved from live-trapped specimens (killed by cervical dislocation) and transported in liquid nitrogen to the laboratory. Tissues were then homogenized in an equal volume of buffer (0.01 M Tris, 0.001 M EDTA, 5 x 10 ' M NADP, pH adjusted to 7.0 with HCl), cen- trifuged for 20 min at 4 C, and stored at —80 C. Hemolysate was maintained at 0-5 C until assayed. Methods of horizontal starch gel electrophoresis and biochemical staining were similar to those described by Selander et al. (1971) and Harris and Hopkinson (1976), with minor modifications. Gels were pre- pared using a 14% concentration of hy- drolysed starch, which consisted of a T.l mix of starch from Sigma Chemical Co. (lot 31F- 0135) and Otto Hillers's Electrostarch (lot 307). A total of 39 presumptive gene loci was consistently resolved across all populations, and the buffer/stain combinations used are summarized in Table 2. Enzyme nomencla- ture follows recommendations of the Nomen- clature Committee of the International Union of Biochemistry (1984), with locus abbrevia- tions following those suggested for lower ver- tebrates by Murphy and Crabtree (1985). We recognize that our nomenclature will depart from that used in most conventional mammal studies, but virtually all of these loci are either known (Fisher et al. 1980) or suspected of being homologous across all tetrapods (Harris and Hopkinson 1976). Multilocus enzyme systems in which ho- mologies are uncertain were simply desig- nated numerically from most to least anodal (Est-'T", -"2", etc.). Alleles were designated numerically, with the most common allele as- signed a value of 100 for anodal and - 100 for cathodal migrants. Other allozymic bands and their corresponding alleles were designated as percentages of distances migrated relative to that of the 100 allele. Individual genotypes were inferred from enzyme phenotypes and statistically analyzed with the BIOSYS-1 pro- gram (SwofiFord and Selander 1981). Measures of genetic variability computed for each popu- lation include average locus heterozygosity (H, direct count), percent loci polymorphic (P), and mean number of alleles per locus (A). October 1987 Dobson etal: Cliff Chipmunk Variation Table 1. Summary oi Etitamias dorsalis samples used in the study. 553 Locality N Ele\ati{)n (m) Museum deposition DC = Deep Creek Mountains Indian Farm Canyon Toms Creek 22 2 1650-2400 1800 BYU 7404-06,7409-28 BYU 7407-7408 HR = House Range Marjum Pass Painter Creek 18 13 1800-2100 1800-2400 BYU 7429-7446 BYU 7447-7459 RR = Raft River Mountains Clear Creek 13 1800-2100 BYU 7471-7483 Oq = Oquirrh Mountains Ophir Canyon 11 1800-2250 BYU 7460-7470 WW = Wah Wah Mountains Pine Grove 9 1800-2250 BYU 7396-7403 St = Stansbury Mountains Johnson Pass 2 1800-1950 BYU 7484-7485 The genetic distance and similarity coeffi- cients of Nei (1972, 1978) and Rogers (1972) were calculated for all pairwise comparisons of samples, and all such matrices were clustered by the UPGMA algorithm of Sneath and Sokal (1973). Wright's (1965, 1978) F-statistics were calculated for all variable loci, each popula- tion was tested for conformance to Hardy- Weinberg expectations using Levene's (1949) correction for small sample sizes, and inter- sample allele-frequency heterogeneity was evaluated by the contingency Chi-square method of Workman and Niswander (1970). Results Patterns of variability. — Of the 39 loci scored in E. dorsalis, the following 18 loci were monomorphic for the same allele in all six populations: Adh-A, Ap-A, M-Aat-A, S- Aat-A, Pep-B, Pep-D, Esterases 1, 2, 4, and 5, Gpi-A, Gtdh-A, G3pdh-A, M-lcdh-A, Ldh- B, M-Mdh-A, Sod-"2", and P-alb. Allelic fre- quencies of the 21 polymorphic loci are given in Table 3. The Stansbury Mountain sample was fixed for S-Mdh-A, M-Me-A, and Xdh-A alleles that were rare or absent from the other samples. The Deep Creek sample varied at four loci, M-Acon-A, S-Icdh-A, Ldh-A, and Pgm-A, which were monomorphic for the common allele across all other samples. The remaining loci are characterized by differing degrees of polymorphism in different sam- ples. Polymorphism and heterozygosit\'. — Table 3 summarizes estimates of the average proportion of polymorphic loci per sample (P), the average number of loci heterozygous per individual for each sample (H), and the mean number of alleles per locus (A). Estimates of P were calculated using both the .01 and .05 criteria in order to facilitate comparison with other investigators. The proportion of poly- morphic loci per sample (P) averaged 0.15 (range: 0.05-0.25) and 0.20 (range: 0.05- 0.33) for the .05 and .01 levels, respectively. Heterozygosity estimates averaged 0.010 and ranged from 0.005 in the Oquirrh sample to a high of 0.013 in the House Range sample. These estimates appear lower than other reports for this genus, H = 0.061 for E. panaminttis (Kaufman et al. 1973). Estimates of A ranged from 1. 143 for the Stansbury sam- ple, which may be an artifact of small sample size, to a high of 1.857 for the Deep Creek sample. The average across all samples was 1.524. Genetic similarity and distance. — Coefficients of genetic similarity, S (Rogers 1972), and genetic distance, D (Nei 1978), based on the 39 loci assayed were calculated for all pairwise sample comparisons (Table 4). Values of S ranged from 0.891 to 0.976 and for D from 0.001 to 0.086. The Stansbury sample consistently had the lowest S and highest D values. Values from the matrices of intersam- ple genetic similarities and distances were clustered by the UPGMA option of BIOSYS- 1, and dendrograms are presented in Figure 2 (dendrograms of Nei's [1978] I matrix and Nei's [1972] earlier I and D coefficients are available from the senior author upon 554 Great Basin Naturalist Vol. 47, No. 4 Table 2. Enzymes and electrophoretic conditions used in the analysis of Eutamias dorsalis populations. Locus prefixes M and S refer to mitochondrial and supernatant (= cytosolic) loci, respectively; and tissue abbreviations H, He, L, and P refer to heart, hemolysate, liver, and plasma, respectively. Abbreviations of enzymes in parentheses are older names found in most mammal literature. Enzyme Enzyme commission number Locus Buffer conditions^ Tissue Aconitate hydratase Alcohol dehydrogenase Aminopeptidase ("Lap ") Aspartate aminotransferase ("Got-2") Aspartate aminotransferase ("Got-1") Dipeptidase Dipeptidase Dipeptidase Esterases (non-specific) Fumarate hydratase Glucose dehydrogenase Glucose-6-phosphate isomerase ("Pgi") Glucose-6-phosphate dehydrogenase Glutamate dehydrogenase Glycerol-3-phosphate dehydrogenase ("-Gpd ") L-Iditol dehydrogenase ("Sdh ") Isocitrate dehydrogenase ("Idh-2") Isocitrate dehydrogenase ("Idh-1") Lactate dehydrogenase ("Ldh-2") Lactate dehydrogenase ("Ldh-l") Malate dehydrogenase ("Mdh-2") Malate dehydrogenase ("Mdh-1 ") "Malic enzyme" ("Me-2") "Malic enzyme" ("Me-l") Mannose-6-phosphate isomerase Phosphoglucomutase Phosphogluconate dehydrogenase Superoxide dismutase ("Ipo") Superoxide dismutase ("Ipo") Xanthine dehydrogenase General proteins: Albumin Hemoglobin Post-albumin Transferin 4.2.1.3 M- Aeon- A B L M.Ll Adh-A B L 3.4.1L1 Ap-A A P 2.6. LI M-Aat-A B L 2.6.L1 S-Aat-A B L 3.4.12.9 Pep-A B L 3.4.13.9 Pep-B B L 3.4.13.9 Pep-D B L — Est. "l"-"6" D L,P 4.2.1.2 Fum-A B L 1.1.1.47 Gcdh-A B,C L 5.3.1.9 Gpi-A B L 1.1.1.49 G6pdh-A B L 1.4.1.2 Gtdh-A B L 1.1.1.8 G3pdh-A B L 1.1.1.14 Iddh-A B L 1.1.1.42 M-Icdh-A B L 1.1.1.42 S-lcdh-A B L 1.1.1.27 Ldh-A C L 1.1.1.27 Ldh-B C L 1.1.1.37 M-Mdh-A B L 1.1.1.37 S-Mdh-A B L 1.1.1.40 M-Me-A B L 1.1.1.40 S-Me-A B L 5.3.1.8 Mpi-A B L 5.4.2.2 Pgm-A B L 1.1.1.44 Pgdh-A B L 1.15.1.1 Sod-"l"' B L 1.15.1.1 Sod-"2" D L 1.2.1.37 Xdh-A B L Alb A L,H — Hb-"1" A He — P-alb A L,H — Trf A L,H 'Nomenclature and EC numbers follow recommendations of the Nomenclature Committee of the International Union of Biochemistry (1984). ^Buffers used; A— Tris-hydrochloric acid pH 8. 5, 50 ma for 5 hr. B— Tris-citrate pH 8.0, 75 ma for 6 hr; C^Tris-citrate pH 6.7, .50 ma for 6 hr; D— Pouhk pH 8.7, 50 ma for 10 hr ■'Substrates for dipeptidases A, B, and D were glycyl-L-leucine, DL-leucylglycylglycine, and L-phenylalynyl-L-proline, respectively. ■"NADP-dependent malate dehydrogenase Locus homologies with lower vertebrates uncertain ^Eutamias hemoglobin is encoded by two loci (Jensen et al. 1975), but the single locus resolved in this study is arbitrarily designated Hb-'l". request). In all dendrograms generated, five samples are very similar (S values 0.94-0.98) and consistently cluster in one branch, whereas the Stansbury Mountain sample is comparatively very divergent (average S ^ 0.90). Population structure. — A summary of F statistics for all variable loci is presented in Table 5, excluding those for the small Stans- bury sample. The inbreeding coefficients (Fjg) ranged from -0.016 to 1.000 with a mean of 0.320. The standardized gene frequency vari- ance (Fsx) values ranged from 0.013 to 0.196 with a mean of 0.094. Chi-square tests were performed to test for deviation of genotypes from Hardy- Weinberg expectations for all variable loci in all but the Stansbury sample, and surprisingly, all sam- ples showed significant deviation at some loci, due to the presence of rare homozygotes. The House Range sample, for example, had no heterozygotes at G-6-pdh (30 100/100 and 1 October 1987 Dobson etal: Cliff Chipmunk Variation 555 Table 3. Allele frequencies and estimates of genie variability in six samples of Eutamias dorsalis. Locality abbreviations are from Table 1 and Figure L Allele Sample sizes and localities Locus (N=9) WW (N = 24) DC (N = ll) Oq (N = 13) RR (N = 31) HR (N=2) St M-Acon-A 88 100 0.0 LOGO 0.042 0.958 0.0 1.000 0.0 1.000 0.0 1.000 0.0 1.000 Est-"3" 86 100 107 105 110 0.167 0.556 0.222 0.056 0.0 0.125 0.875 0.0 0.0 0.0 0.0 0.545 0.455 0.0 0.0 0.0 1.000 0.0 0.0 0.0 0.0 0.871 0.129 0.0 0.0 0.0 0.500 0.250 0.000 0.250 Est-"6" 90 100 105 110 0.278 0.556 0.167 0.0 0.083 0.792 0.083 0.042 0.091 0.545 0.364 0.0 0.154 0.692 0.077 0.077 0.194 0.710 0.097 0.0 0.0 0.500 0.500 0.0 Fum-A 100 188 1.000 0.0 0.875 0.125 1.000 0.0 0.962 0.038 0.887 0.113 1.000 0.0 Gcdh-A 100 110 1.000 0.0 1.000 0.0 1.000 0.0 1.000 0.0 0.968 0.032 1.000 0.0 G6pdh-A 100 108 1.000 0.0 1.000 0.0 1.000 0.0 1.000 0.0 0.968 0.032 1.000 0.0 S-Icdh-A 100 112 1.000 0.0 0.979 0.021 1.000 0.0 1.000 0.0 1.000 0.0 1.000 0.0 Iddh-A 100 387 1.000 0.0 0.938 0.062 1.000 0.0 0.962 0.038 1.000 0.0 1.000 0.0 Ldh-A 100 125 1.000 0.0 0.958 0.042 1.000 0.0 1.000 0.0 1.000 0.0 1.000 0.0 S-Mdh-A 84 100 105 0.0 1.000 0.0 0.0 1.000 0.0 0.0 1.000 0.0 0.038 0.924 0.038 0.0 1.000 0.0 1.000 0.0 0.0 M-Me-A 75 100 110 0.0 1.000 0.0 0.167 0.813 0.020 0.091 0.909 0.0 0.077 0.923 0.0 0.0 1.000 0.0 1.000 0.0 0.0 S-Me-A 50 100 0.0 1.000 0.208 0.792 0.0 1.000 0.0 1.000 0.065 0.935 0.0 1.000 Mpi-A 100 115 1.000 0.0 1.000 0.0 0.955 0.045 1.000 0.0 0.935 0.065 1.000 0.0 Pep-A 100 120 1.000 0.0 1.000 0.0 1.000 0.0 1.000 0.0 0.984 0.016 1.000 0.0 Pgm-A 35 100 0.0 1.000 0.083 0.917 0.0 1.000 0.0 1.000 0.0 1.000 0.0 1.000 Pgdh-A 118 100 0.333 0.667 0.0 1.000 0.0 1.000 0.0 1.000 0.0 1.000 0.0 1.000 Sod-"l" 60 100 130 0.111 0.889 0.0 0.0 0.771 0.229 0.143 0.714 0.143 0.0 0.846 0.154 0.0 0.968 0.032 0.0 1.000 0.0 Xdh-A 40 100 110 0.0 1.000 0.0 0.166 0.792 0.042 0.182 0.818 0.0 0.077 0.923 0.0 0.0 1.000 0.0 1.000 0.0 0.0 Alb 100 110 0.889 0.111 1.000 0.0 1.000 0.0 1.000 0.0 1.000 0.0 1.000 0.0 Hb-"1" 80 100 120 0.056 0.944 0.0 0.020 0.917 0.063 0.0 0.955 0.045 0.0 0.923 0.077 0.065 0.903 0.032 0.0 1.000 0.0 556 Great Basin Naturalist Vol. 47, No. 4 Table 3 continued. Sample sizes and localities (N = 9) (N----24) (N-11) (N-13) (N-31) (N = 2) Locus Allele WW DC Oq RR HR St Trf 100 0.889 1.000 1.000 1.000 0.968 1.000 120 0.111 0.0 0.0 0.0 0.0.32 0.0 Polymorphic per sample (P)* (.05) 0.179 0.256 0.128 0. 154 0. 154 0.051 (.01) 0.179 0.325 0. 175 0.200 0.275 0.051 Average heterozygosity per individual (H)** 0.048 0.024 0.042 0.028 0.036 0.050 Mean number of alleles per locus (A) 1.476 1.857 1.478 1.571 1.619 1.143 *A locus is considered polymorphic if the frequency of the most common allele does not exceed 0.95 (.05 criterion) or 0 99 (01 criterion) **Estimate of H determined by direct count. Table 4. Matrix of genetic similarity S (Rogers 1972) above the diagonal and genetic distance D (Nei 1978) below the diagonal for six samples of E. dorsalis. Abbreviations of populations follow Table 1. Population WW DC Oq RR HR St Wah Wah Mtns. 0.941 0.962 0.963 0.965 0.891 Deep Creek Mtns. 0.010 — 0.959 0.969 0.964 0.891 Oquirrh Mtns. 0.004 0.007 — 0.969 0.964 0.912 Raft River Mtns. 0.006 0.002 0.006 — 0.976 0.901 House Range 0.005 0.003 0.005 0.001 — 0.894 Stansbury Mtns. 0.086 0.071 0.066 0.075 0.085 — 108/108 genotypes) and Sod-"l" (30 100/100 and 1 130/130), X' = 61.02 (1 df), P < .001. Samples from the Oquirrh, Raft River, and Wah-Wah Mountains had no heterozygotes at three loci each, as follows: (1) Oq — M-Me-A (10 100/100 and 1 75/75, X' = 21.05 with 1 df), Sod-"l" (5 100/100, 1 60/60, and 1 130/130; 4 individuals unscorable; X" = 26.22 with 1 df), Xdh-A (9 100/100 and 2 40/40, X' = 14. 12 with 1 df), P < .001; (2) RR— M-Me-A (12 100/100 and 1 75/75, X' = 25.04 with 1 df), Sod-"l" (11 100/100 and 2 130/130, X' - 16.76 with 1 df), Xdh-A (12 100/100 and 1 40/40, X' - 14.12 with 1 df), P < .001; (3) WW— Pgdh-A (6 100/100 and 3 118/118, X^ - 10.47 with 1 df), Sod-"l" (8 100/100 and 1 60/60, X^ - 17.01 with 1 df), Trf (8 100/100 and 1 120/120, X' = 17.01 with 1 df), P < .001. The same trend was evident in 8 of 13 polymorphic loci in the Deep Creek sample: M-Acon-A (23 100/100 and 1 88/88, X' = 47.02 with 1 df), Ldh-A (23 100/100 and 1 125/125, X' - 47.02 with 1 df), Pgm-A (22 100/100 and 2 35/35, X' = 31.38 with 1 df), Fum-A (21 100/100 and 3 188/188, X^ = 28.27 with 1 df), S-Me-A (19 100/100 and 5 50/50, X' = 26.25 with 1 df), Sod-"l" (19 100/100 and 5 130/130, X' = 26.25 with 1 df); M-Me-A (19 100/100, 4 75/75, and 1 100/110, X' - 26.96 with 3 df); Xdh-A (19 100/100, 4 40/40, and 1 110/110, X' = 73.99 with 3 df); P < .001 in all cases. Discussion Allopatric populations of cliff chipmunks sampled had weak interpopulational diver- gence (average D = 0.028), with the Stans- bury sample strongly divergent from others (average D = 0.74) while the remaining sam- ples are only slightly divergent from each other (average D = 0.005, Fig. 2). The small D values are consistent with those calculated for other mountain-top species of small ro- dents (Mewaldt and Jenkins 1986, Sullivan 1985). The divergence of the Stansbury Mountain sample is primarily due to the fixation of three alleles, S-Mdh-A(84), M-Me- A (75), and Xdh-A (40) (Table 3) that were rare or absent in the rest of the samples. This sample also had a unique Est-3 (110) allele at 0.25 frequency, but because of its small size (2 individuals), some of this difference may sim- ply be a function of a large sampling error. However, the Stansbury population is likely October 1987 DoBSON ETAL; Cliff Chipmunk Variation 557 r t Wah Wah Mlns Oquirrh Mlns Deep Creek Mlns Raft River Mlns House Range Slansbury Mlns 0 10 0 09 0( 1 1 1 T 1 1 1 1 0 07 0 06 0 05 0 04 0 03 0 02 0 01 0 00 Wah Wah Mlns Deep Creek Mlns Oquirrh Mlns Rail River Mlns House Range Slansbury Mlns I I 1 I 1 1 1 1 1 1 1 0 90 0 91 0 92 0 93 0 94 0 95 0 96 0 97 0 98 0 99 100 Roger's (1972) S Fig. 2. UPGMA dendrograms of genetic distance val- ues (Nei 1978), A, and similarity values (Rogers 1972), B, for six samples oi Eiitamias dorsalis. Sample localities are those shown in Figure 1; cophenetic correlation values are 0.991 and 0.975, respectively. very small, as evidenced by very low capture success per unit effort compared to other sam- ples, and it appears to be restricted to one canyon. Thus, the relatively large level of ge- netic divergence may also reflect the influence of a recent population bottleneck and/or pronounced genetic drift. The overall mean Fsj value of 0.094 (Table 5) suggests an appreciable level of subdivision between the montane populations, although much higher levels are known in other small mammals (Fsj = 0.412 for Thomomys bottae, for example; see Patton and Yang 1977). Ap- preciable substructuring in populations may result from population bottlenecks and the ensuing influence of drift (Schwartz and Ar- mitage 1980), and the winter of 1982-83 was one of the most severe on record in Utah (NOAA 1983). This may have reduced popula- tion sizes, forcing inbreeding and fostering a breeding structure in which drift could have a pronounced influence. However, if we invoke an explanation of differentiation by climati- cally caused population bottlenecking and subsequent drift for the Stansbury sample, we must also account for the extensive polymor- Tablk 5. Summary of F-statistics for all variable loci across all examined samples oi Eiitamias dorsalis except Stansbury Mountains. Locus F,s Fn M- Aeon- A Est-".3" Est-""6" Funi-A Gcdh-A G-6-pdh-A S-Icdh-A Iddh-A Ldh-A S-Mdh-A M-Me-A S-Me-A Mpi-A Pep-A Pgm-A Pgdh-A Sod-"l" Xdh-A Alb Hb-"1" Trf 1.000 -0.259 -0.211 0.517 0.033 1.000 -0.021 -0,0.56 1.000 -0.061 0.933 0.714 -0.060 -0.016 1.000 1.000 1.000 1,000 -0,125 -0,072 0,752 1.000 -0.002 -0.148 0.544 -0.006 1.000 -0.004 -0.021 1.000 0.012 0.937 0.750 -0.022 -0.003 1.000 1.000 1.000 1.000 -0.023 -0.058 0.770 0.034 0.196 0.052 0.056 0.026 0.027 0.017 0.034 0.034 0.047 0.066 0.127 0.035 0.013 0.068 0.286 0.068 0.083 0.091 0.013 0.071 Mean 0.,320 0.,384 0.094 phism observed in the other samples (e.g., DC and HR), which presumably were also subject to the same severe conditions. It is unlikely that the observed polymorphism of alternate alleles could have been accumulated in each population in the short time since the Postpluvial, 7500 years B.P., when desert ad- vancement last isolated mountain ranges. Two alternate explanations are proposed. First, one large, genetically variable popula- tion may have been widely distributed across the Great Basin and subsequently became fragmented and restricted to mountain ranges by the Pleistocene climatic shifts. This is the vicariance explanation proposed by Patterson (1980, 1982) for montane mammal popula- tions in New Mexico. This hypothesis would predict near genetic uniformity and very low between-population divergence in the ab- sence of drift, isolation by distance (Wright 1965), or some behavioral mechanism con- tributing to small, effective breeding sizes and nonrandom mating. Alternately, since chip- munks are reported from the Pliocene of North America (Black 1972), E. dorsalis as a species may predate the Pleistocene and may have entered the Great Basin from the Rocky Mountains or some other center of origin. Pleistocene ice ages repeatedly forced floral 558 Great Basin Naturalist Vol. 47, No. 4 and faunal elements to lower elevations and may have facilitated intermittent gene flow among chipmunk populations. This may have been sufficient to maintain allelic variants in most populations. Without additional genetic information from hypothesized source popu- lations (i.e., Wasatch Range) and others more distantly isolated in Great Basin mountain ranges, we cannot choose among these alter- natives. Ecological and behavioral factors may be as important as historical events in determining the genetic structure of chipmunk popula- tions. For example, in addition to the disper- sal barriers between populations (i.e., desert valleys, lakes, rivers, and distance), chip- munks also face problems of short-distance dispersal imposed by complex, interspecific competition, interspecific territoriality (Broad- books 1970, Brown 1971b, Heller 1971), habi- tat requirements (Sharpies 1983), predation, altitudinal zonation (Chappell 1978, Heller 1971), and philopatry to home range (Broad- books 1970, Martinsen 1968, Sheppard 1972). Broadbooks (1970), Martinsen (1968), and Sheppard (1971) found three significant be- havioral characteristics of yellow-pine chip- munks (£. amoentis) and least (£. lywwnus) chipmunks that would influence the geo- graphic distribution of allele frequencies: (1) chipmunks have a well-defined home range in which they remain from year to year, (2) a high percentage (8 of 11) of the offspring remain in the area of the parent, and (3) 67.4% of chip- munks released .4 km from their home range returned within 1-3 days after release. If similar behavior is typical of £. dorsalis populations, then breeding units may be char- acterized by high incidences of parent-off- spring or sib matings. Some evidence of in- breeding is given by the F-statistics. For example, when averaged across all samples, F,s values were mostly high and positive, an indication of heterozygote deficiency for many loci (Table 5). This is due to the com- plete absence of heterozygotes at some loci in the five localities for which sample sizes were statistically "adequate" (all but Stansbury). The Fjs values may reflect either high levels of inbreeding or further levels of subdivision within our "samples" of £. dorsalis, but other explanations are possible. For example, the frequent occurrence of double homozygotes in some loci segregating three alleles (Xdh-A and S-Me-A in the Deep Creek sample, and Sod-"r in the Oquirrh Mountain sample) also suggests the possibility of linkage disequi- librium in small, nonrandom mating popula- tions. Several other studies have shown that small population size per se is not always ac- companied by strong inbreeding, as various species of mammals avoid consanguinous mat- ings by a number of behavioral mechanisms (Foltz and Hoogland 1983, Hoogland 1982, Patton and Feder 1981, Schwartz and Ar- mitage 1980). Patton and Feder (1981), for example, found a paradoxical situation in which high heterozygosity was maintained in apparently very small breeding units of the gopher Thomomijs hottae, and this was ex- plained as an equilibrium achieved between the rate of migration (either recolonization following extinction or individual recruitment into groups) and the effective number of indi- viduals that are contributing to the breeding effort each year. We do not have the ecological or pedigree information necessary to evaluate the importance of these factors in E. dorsalis, but their prevalence in other rodents, and the previously mentioned behavioral traits of other Eiitamias, collectively suggest that in- breeding alone cannot explain all of the ob- served heterozygote absences in these popu- lations. If it did, it should have a more or less equal influence across all variable loci, and this is not the case (Table 3). Alternatively, the high frequency of fixed allelic differences among different individuals within the same sample suggests that we may well have pooled breeding units that differed drastically in their allelic composition (Wahlund effect). The Deep Creek sample displayed heterozygote deficiencies at eight loci and was comprised of collections from two different localities (Table 1, Fig. 1), but the excess number of homozygotes in the total sample did not correlate with the numbers of individuals from either of these two sites. In other words, this effect did not disappear when these samples were analyzed sepa- rately. Similarly, the House Range sample was collected from two localities and showed heterozygote deficiencies at five loci; again the phenomenon was independent of sample localities. The Oquirrh and Raft River sam- ples were collected from one canyon each, and both samples showed heterozygote deficiencies at the same three loci (S-Me-A, October 1987 DoBSONETAL: Cliff Chipmunk Variation 559 Sod-"l", and Xdh-A). Chesser (1983) has shown that important patterns of genetic vari- abihty may be obscured when breeding units are pooled together, and we suspect that our "samples ' of £. dorsalis may include separate Mendelian units that may differ drastically in allelic composition at some loci. We recognize the risk of over-analyzing these data in light of the small sample sizes but feel that at least some other possible explana- tions for the complete absence of het- erozygotes at many loci can be ruled out. The possibilities include: (1) inadvertant inclusion of a second species of Eutamias in the sam- ples, (2) scoring of multiple loci for some en- zyme systems in only select individuals from each sample, and (3) enzyme denaturation and/or posttranslational modification of gene products in select individuals. Eutamias minimus is sympatric with E. dor- salis at all localities sampled, but the latter is very distinct, and CLP and MLD have had considerable experience with both species. Museum voucher specimens were prepared for all individuals used in this study, and a recheck confirmed their identification as E. dorsalis. We conclude that there is almost no chance of "mistaken identity and that this explanation would not, by itself, account for the different locus combinations displaying heterozygote absence at the five localities tested. Second, we can rule out the likelihood of scoring different loci from a multilocus en- zyme in different individuals from the same populations, because the number of loci en- coding the enzymes used in this study is well known in mammalian systems (Harris and Hopkinson 1976). A single tissue type was used in most electrophoretic runs (liver, see Table 2), but even when others were used, multilocus systems were evident either as two zones of activity on the same gel, or as differ- ent patterns of variability evident in different tissues of the same individual. The rare ho- mozygotes we resolved were scored as such from zones of different mobility in one or a few individuals on gels that otherwise contained a single electromorph common to all other specimens, with the same tissue type being used throughout. The problem of enzyme denaturation and/ or posttranslational modification is more difficult to assess. Moore and Yates (1983) evaluated rates of protein inactivation (for 27 enzymes) under controlled conditions in four species of mammals of varying body size {An- tilocapra amcricana, Plecotiis townsendii, Dipodomijs ordii, and Peromyscus boijlii) and found that 95% of the proteins routinely ex- amined electrophoretically are still stable (i.e., not denatured and showing mobilities identical to controls) in unfrozen tissues for a minimum of 12 hrs after death. The locus Sod-'l" had no heterozygotes in all five of the E. dorsalis samples but was one of the most stable systems studied by Moore and Yates (1983); the least stable system examined by them, ADH, was not included in our protocol (Table 2). Further, our method of obtaining animals from the field insured that tissues were taken from specimens and frozen in liq- uid nitrogen within 30 min of capture. Labo- ratory protocol for homogenizing and storing tissue samples was consistent throughout the study, so there seems to have been little op- portunity for extensive contamination or de- naturation of the samples. The possibility of epigenetically or post- translationally modified electromorph mobili- ties (see Lebherz 1983) in some E. dorsalis specimens is one that we cannot evaluate with the information we have. Some classes of these alterations are known to have a genetic basis in some organisms (Womack 1983, Dykhuizen et al. 1985), and in at least one rodent species, mobility differences in two different loci (Trf and Ap-A) seem to vary with the physiological state of the animal (McGov- ern and Tracy 1981). If this is the explanation for most or all of the rare homozygotes we encountered, then the physiologically or ge- netically based phenomenon for such electro- morph mobility alterations must be wide- spread in £. (forsa/js populations. Elimination of these individuals from our analyses would lower the mean inbreeding coefficient (F,s) and perhaps slightly decrease mean D and Fst values, although our conclusions about a mod- erate level of population subdivision and min- imum genetic divergence would be virtually unaltered. We suggest that the montane mammal pop- ulations of the Great Basin offer excellent model systems for addressing issues in island biogeography and population biology, but that future sampling strategies be designed to collect an adequate number of individuals 560 Great Basin Naturalist Vol. 47, No. 4 (n = 25, if possible) from a single ecologically homogenous site, and that, for larger moun- tain ranges at least, two or more localities be collected and analyzed as separate population samples in order to assess within, as well as between, mountain range divergence. Such control in sampling will allow for a more rigor- ous assessment of macrogeographic patterns of gene flow and population structure. 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Wells, P H , and R Berger 1967. Late Pleistocene history of coniferous woodland in the Mohave Desert. Science 155: 1640-1647. Womack, J E 1983. Post-translational modification of enzymes: processing genes. Pages 175-186 in M. C. Rattazzi, J. G. Scandalios, and G. S. Whitt, eds.. Isozymes: current topics in biological and medical research. Vol. 7. A. R. Liss, New York. Workman, P. L., and J. D. Nisvvander. 1970. Population studies on southwestern Indian tribes. 11. Local genetic differentiation in the Papago. Amer. J. Hum. Genet. 22:24-49. Wright, S 1965. The interpretation of population struc- ture by F-statistics with special regard to systems of mating. Evolution 19:395-420. 1978. Evolution and the genetics of populations. Vol. 4. Variability within and among natural popu- lations. University of Ghicago Press, Chicago. OBSERVATIONS ON THE ECOLOGY AND TROPHIC STATUS OF LAKE TAHOE (NEVADA AND CALIFORNIA, USA) BASED ON THE ALGAE FROM THREE INDEPENDENT SURVEYS (1965-1985) Sam L. VanLandingham' Abstract. — Numerous physical, chemical, and biological criteria evidently confirm that Lake Tahoe is oligotrophic. However, detailed examination of the ecology and trophic status of algae (mostly diatoms) from Lake Tahoe taken from three independent, long-term sampling programs aided in interpretation of plankton and periphyton algal communi- ties by spectral analysis (supported by computerized data synthesis) and suggested that the prevailing trophic disposition of this deep, subalpine lake no longer can be described as "ultra-oligotrophic" or typically oligotrophic. Although at various places in recent years there has been some increase in oligotrophic species that seems to correspond with recent sewage export from the Tahoe basin, there was a marked tendency toward mesotrophy and/or eutrophy over most of the lake from April 1965 through October 1985. This study posits the speculation that there may be other "ultra-oligotrophic" lakes over the world from which future studies may reveal algal communities that may be described as more mesotrophic and/or eutrophic than oligotrophic. Lake Tahoe probably is not as oligotrophic as is generally believed, and the indicator algae in it are not as accurate as is generally believed. There have been few American lakes that have inspired such curiosity, commentary, lore, and interest among scientists as Lake Tahoe. From the time of Ehrenberg (1871), there has been considerable controversy and speculation in connection with the limnology of Lake Tahoe. Statements describing Lake Tahoe as "a remarkably unproductive sub- alpine environment" (Mahood et al. 1984) and as "still one of the most oligotrophic lakes in the world" (Goldman 1974) seem misleading; on the other hand, such comments as "heavy periphyton growth" and "alarming increase in primary productivity" (Goldman and De Amezaga 1975) and "it is beginning to show signs of the earliest stages of eutrophication" (Mahood et al. 1984) are equally perplexing. In addition, Goldman (1981) reported that the annual productivity of the pelagial water of Lake Tahoe has more than doubled in the past two decades. Moreover, I find the terming of Lake Tahoe as "extremely oligotrophic" (Goldman and Armstrong 1969) and "ultra- oligotrophic" (Tilzer and Home 1979) enig- matic in view of the obvious enrichment of the littoral areas. Indications of mesotrophy and eutrophy demonstrated by the algae in the lake are conspicuous, and Tahoe no longer can be considered "one of the most oligotrophic lakes in the world." The California-Nevada-Federal Water Pol- lution Control Administration (FWPCA) survey confirmed that Lake Tahoe was olig- otrophic mainly on the basis of low zooplank- ton and phytoplankton counts, low periphy- ton densities, and low P (5 |xg 1^) and N (IQO |xg r') concentrations. A large number of spe- in Lake Tahoe was described as eu- cies trophic, although their presence was not considered to be indicative of eutrophic con- ditions (California Department of Water Re- sources 1966). Total P at many stations in the last 10-15 years seems excessive for an olig- otrophic lake and probably has enhanced the growth of many eutrophic diatoms and other algae. Why are so many of the typical or cos- mopolitan oligotrophic diatoms, such as Melosira distans (Ehr.) Kiitz., Cyclotella ocel- lata Pant., Frustulia rhomboides (Ehr.) De Toni, Navicula radiosa Leud.-Fort., Pinnu- laria biceps Greg., TabeUaria floccidosa (Roth) Kiitz., and Tetracyclus laciistris Ralfs, infrequent or rare in Lake Tahoe? All of these taxa are common in both ancient and modern lakes in this region. Melosira distans, for ex- ample, is a dominant or subdominant species in oligotrophic Suttle and Woahink lakes, Or- egon, in a Pleistocene oligotrophic diatomite '3741 Woodsong Drive, Cincinnati, Ohio 45239. 562 October 1987 VanLandingham: Lake Tahoe 563 deposit about 500 m from the shore of Lake Tahoe at Tahoe City, and in several ohg- otrophic dry lakes nearby in Nevada. The rar- ity of the above-mentioned diatoms can be explained partially by the observation that most of these taxa prefer acidic waters and that Lake Tahoe nearly always has a pH above 7. Only a very few oligotrophic diatoms, such as Cyclotella stelligera (CI.) V.H., Achnanthes minutissima Kiitz. , and Anoinoeoneis exilis (Kiitz.) Cl., ever attain noteworthy promi- nence in Lake Tahoe. Weber (1970) used plankton counts of less than 500 cells/ml as one of many criteria for determining oligo- trophic lakes. In recent years cell counts for the planktonic algae occasionally have ex- ceeded 500 cells/ml in littoral areas. Problems associated with interpreting trophic or inorganic nutrient categories in lakes are numerous. Whiteside (1983) con- tends that the oligotrophy-eutrophy concept is best interpreted in its original sense, namely, referring to nutrient levels (or com- munity structure) in lakes, and is inappropri- ately used when referring to the aging pro- cess, morphometry, etc. It follows that it may be possible for a lake to be deep or in the youthful stages of ontogeny but have rela- tively high nutrient levels. Or, a lake may be shallow or in the oldest stages of ontogeny but have lower nutrient levels. Sometimes lakes defy assignment to a definite trophic status as La Perriere et al. (1975) demonstrated in re- spect to a deep, subarctic lake. The occur- rence of certain diatoms, which generally are considered eutrophic, seems to be influenced more by such factors as temperature than by trophic levels. For instance, Weber (1973) pointed out that Melosira islandica O. Miill. is considered eutrophic in northern Europe, but in North America it is found only in cold, oligotrophic water both in higher latitudes and higher altitudes at lower latitudes. Fragi- laria pinnata Ehr. and F. crotonensis Kitt. are examples of diatoms that generally are consid- ered eutrophic but that occur commonly in oligotrophic lakes (California Department of Water Resources 1966). No matter what the descriptive or semantic status of Lake Tahoe may be, there is good evidence that its algae frequently indicate relatively moderate to high nutrient levels, and they apparently have done so for many years. Computer Data Synthesis Continuous algal ecological spectral analy- sis reference system (CAESARS) is a compre- hensive, computerized retrieval plan based on approximately 3,000 publications from which about 500,000 bits of information con- cerning over 4,000 common and widely occur- ring algae taxa are categorized into nine physi- cal, chemical, and occurrence spectra, each of which is subdivided into four or more cate- gories (Figs. 1-4). Categories of each spec- trum are based on theoretical and natural ob- servations found in Kisseleva (1939), Foged (1963), Reimer (1965), Round (1965), De Smet and Evens (1972), Schoeman (1973), Friedrich (1973), Lowe (1974), and Tem- niskova-Topalova and Misaleva (1982). Im- portant expoundings on each of the nine spec- tra are: pH (Hustedt 1937, Merilainen 1967, Cholnoky 1968), saprobian (Kolk-witz and Marsson 1908, Caspers and Schulz 1960, Fjerdingstad 1964, 1965a, 1965b, Caspers and Karbe 1967, Sladecek 1967, 1969, 1973, Schoeman 1979, Lange-Bertalot 1979a, 1979b), nutrient (Rawson 1956, Sparling and Nalewajko 1970), halobion (Kolbe 1927, Legler and Krasske 1940), current (Shirshov 1933, Zelinkaand Marvan 1961, Blum 1963), general habitat, specific habitat, and seasons (Schroder 1939, Whitford and Schumacher 1963, Hutchinson 1967, Symons 1970, Staker 1976, Pudo 1979, Moore 1981), and tempera- ture (Louis and Aelvoet 1969, Friedrich 1973). Information from new references is used continuously to update CAESARS. Most terminology used in the categories of the spectra is self-explanatory or in common use, but Lowe (1974) and VanLandingham (1982) give detailed descriptions of each category and spectrum. A series of histograms can be made (Figs. 1-4) by calculating the percent- age of each taxon in each sample and totaling the percentages of all taxa in each category. These spectral categories and/or histograms have proven to be ideal as a standard of eco- logical comparison for various algal samples from all over the world (Collingsworth et al. 1967, Duthie and Rani 1967, VanLandingham 1968, 1970, 1972, 1976, 1982, Messina-Allen and VanLandingham 1970, Robbins and Hohn 1972, VanLandingham and Jossi 1972, Abbott and VanLandingham 1972, Lowe 564 Great Basin Naturalist Vol. 47, No. 4 STATION I 0 50% STATION 2 50% STATION 3 STATION 4 STATION 5 50% 0 50% 0 50% Acidobiontic j M ■[ 1 Atidophilous ■ L Indifferent I I ■^ ■■■ 1 1 ■ I^H - ■■ Alkaliphilous ■ ■ r 1 tpPB ■■. Alkalibiontic E r ^T 1 Unknown or other 1 Polysaprobic or Saprobiontic [ Mesosaprobic 1 1 alpha range (strong) 1 1 beta range (weak) 1 1 1 L Oligosaprobic Hl^H ■■■ Saprophilic j 1 j III rr LL Saproxenous I^^^H JPE ^^ ■1 Katharobic or Saprophobic X T Unknown or other 1 ■ cc 1 Polytrophic Eutrophic ■■ I L ^^H ^^H Uesotrophic ■p II ^^ ■ Oligotrophic mm ^ ^^H tpi^ Dystrophic u 1 Unknown or other ■ 3 3 Euhalobous or Polyhalobous Uesohaiobous alpha range (strong) beta range (weak) 1 L L Oligohalobous \ II II 1 ^■1^ ■^i_ t^i- Halophilous T -■ 1 1 1 1 1 TT Indifferent ■ ■■■L pfP^"" Halophobous r 1 _i_ ! Euryhalobous or Euryhaline L ■ X- Unknown or other 1 , M Limnobiontic L_ r 1 m ■ I^H PBi- !■ Indifferent \ I _^H r Hheophilous Rheobiontic V Unknown or other 1 | 1 Bent hie ■ 1 Lentic Lakes Ponds ^^^^^H 1^^ Bogs or Swamps :renophilous (general) Lotic CIrenophilous (thermal) Rivers i Streams ( 1 I I Aerophilous or Terrestrial 1 1 r r Estuarine 1 L L L Littoral (Litoral) llH ■1 II II Neritic Oceanic Eurytopic or Euryecious 1 1 1 1 Unknown or other ^H ^1 1 1 11 i u 3 Planktonic (Pelagic) ■ 1 I n^^^i 1 II^^^^H 1 1 1 Euplanktonic W _■ 1 1 1 Tychoplanktonic 1 | r L b [ Periphytic (Aufwuchs) ■ I 1 Epipelic [_ r r 1 Epilithic n L Epiphytic ■ 1 ■ 1 Other Periphytic n r r 1 Unknown or other H _i 1 w Winter I 1 ■ 1 H Spring If II ■ 1 ll II ■ ■ Summer m r Fall ■■ IWi r ^1 ll , 5 1 Euthernal 1 1 1 1 LN 1! 1 Hesothermal h J T \ ILL i - Oligothermal ■ ^ HP ■ HI^^^H 11 Stenothermal L Metatherraal ^_ Eurytherraal 1 1 1 pa ■Ml Unknown or other 1 1 _J L_ _ 1 IT ■ ■ n Fig. 1. Spectral histograms based on diatom species percentages from plankton grab samples on 6-8 February 1967 by the California-Nevada-FWPCA survey. October 1987 VanLandinghaM: Lake Tahoe 565 ■STATION 5 UNITED STATES COAST GUARD PIER 10/20/1965- 0 1 1 1 1 1/25/1966 12/12-12/20/1966 50% 0 50% 1 1 1 1 1 1 1 1 1 1 12/20/966-1/4^67 1/4- 0 50% 0 1 1 1 1 1 < 1 1 1 I/I8/I967 50% 1/18 L l._ _ -2/13/1957 50% 1(111 X Acidobiontic 1 ! Acidophil ous 1 k L Indifferent 1 1 I^H ■1 Alkaliptiilous Hh 1^ 1 ■ IJ^^^^H 1 Alkalibiontic 1 1 1 n 1 u Unknown or other ^B ■ ■ 1 ■ 2: < a. (/I Polysaprobic or Saprobiontic r _i_ Mesosaprobic 1 1 I 1 alpha range (strong) | m 1 ■ beta range (weak) 1 . !■ p Oligosaprobic l^^^l 1 ^p PP^ r 1 Saprophilic 1 1 1 ^^ 11 Saproxenous 1 ■ 1 Katharobic or Saprophobic | r L Unknown or other WM ■1 ■ P^X 1 I 1 Polytrophic n^ [T^ r Eutrophic 1 1 p^^H 1 II ■ 1 P^E I^^K - llesotrophic r % m L Oligotrophic u Fp , Dystrophic L L Unknown or other WM ^^H ■ i o 3 Euhalobous or Polyhalobous 1 r Uesohalobous 1 alpha range (strong) 1 1 1 beta range (weak) 1 Oligohalobous ■ I 1 1 Halophilous li ^H Indifferent I ■ ■ ■ ■■ 1 ■■ jjH Halophobous r X 1 Euryhalobous or Euryhaline | 1,1 L 1 1 Unknown or other p^ iJr ii 1 1 o Limnobiontic | | T'' L 1 1 Liumophilous 1 | 1 1 . - L 1 Indifferent ■■ 1 ll^B 1^ ^^^^M Hheophilous m ■ 1 urn ■■ Rheobiontic | T 1 1 1 Unknown or other 1 1 I^E W\ i 1 s a Bent hie h Lentic Lakes I Ponds ■■ li 1 I^H ll 11 IB Bogs or Swamps 1 Lotic Crenophilous (general) -1 1 Crenophilous (thermal) L L Rivers & Streams ■■ 1 1 ■ 1 !■> ■1 Aerophilous or Terrestrial 1 nr r Estuarine [ L. L_ Uttoral (Literal) fM ^^H niir ipiE Neritic Oceanic Eurytopic or Euryecious 1 1 I 1 L Unknown or other ^^H 1 1 r 1 g i y 3 Planktonic (Pelagic) ^M ■^ IIPK ■■ Euplanktonic T t Tychoplanktonic k • \, Periphytic (Aufwuchs) ■ r Epipelic ■ 1 Epilithic b ■ 1 Epiphytic ll ll 1 Other Periphytic | 1 Unknown or other k ■ 1 a Winter H Spring 1 I - - - - 1 ■ III 1 ■ II I 1 1 ■■ Sumner 1 r Fall p Pi ll 1 ll CO cc (^ << 5 a Eutheraal fT 1 Hesothermal 1 I 1 1 Oligothermal 1 1 Stenothermal Metathermal i Eurythermal pH^^^H 1 WilL Unknown or other j ■ ■1 1 1 ! ■ ■ u L J J J J 1 Ml M m J J J J Fig. 2. Spectral histograms based on diatom species percentages from California-Nevada-FWPCA survey periphy- ton samples taken during intervals designated under each station. 566 Great Basin Naturalist Vol. 47, No. 4 0 FALL 967 50% 1 1 WINTER 0 1 1 1 1 967-1968 50% ! 1 1 0 1 SPRING 1968 50% fill 0 1 SUMMER 1968 50% 1 1 1 1 1 1 1 a Acidobiontic 1 Acidophilous Indifferent ^H f 1 1 |i Alkaliphilous 1 1 Alkalibiontic 1 1 I Unknown or other 1 r i Polysaprobic or Saprobiontic Mesosaprobic alpha range (strong) ^ beta range (weak) I^^^H ~\ ^^^ Oligosaprobic Saprophilic 1 1 1 Saproxenous 1 Katharobic or Saprophobic 1 Unknown or other 1 Polytrophic .. ~^ 1 _j Eutrophic iW^ 1 II ■^ 1 1^ 1 ■PH 1 Jesotrophic |e r ^ 7^ Oligotrophic Mr ipi Dystrophic r 1 I u^ Unknown or other ■ 1 P ■ 1 3 tuhalobous or Polyhalobous [l n n Uesohalobous 1 1 1 ! alpha range (strong) 1 beta range (weak; Olieohalobous ^H 1 ■ ■ Halophilous u n Indifferent p^^^^ Halophobous r I Euryhalobous or Euryhaline 1 L L Unknown or other ■ ■ 1 1 o Limnobiontic 1 n L Limnophilous 1^1 1 1 ■I Indifferent I 1 II 1 1 Kheophilous H I "i Rheobiontic I Unknown or other 1 1 k 1 i a Benthic ■ IL 1 1 Untie Lakes i Ponds ■■ 11 IP Bogs or Swamps 1 r Lotic ^renophilous (general) 1 Crenophilous (thermal) I ■ Rivers !• Streams ^H ■1 pi ■I Aerophiious or Terrestrial 1 ' r r r Estuarine L L L Littoral (Litoral) IH I ■1 ■I Neritic Oceanic Eurytopic or Euryecious 1 1 ! Unknown or other 1 1 Eh S Si Planktonic (Pelagic) 1 ■ m^^^^i 1 IHI Euplanktonic IP II ■ Tychoplanktonic r r 1 Periphytic (Aufwuchs) 1 1 1 1 Epipelic P r r 1 Epilithic k 1 1 h Epiphytic , 1 1 Other Periphytic | ^ Unknown or other L L r b Winter 1 L - - I. - - Spring ■■~ ■■ ■i ■■-- Summer ■ 1 ^^^^1 ■ ■ 1 Fall w 1 1 E 1 5 a Euthernal —^ Hesothermal | | w 1 Oligothermal PP^ ^m lai ■ 1 Stenothermal 1 Metatherraal | - Eurythermal 1 - B 1. Unknown or other ■ L L L u _L1.L _ J J J J Fig. 3. Spectral histograms of diatom species percentages from averages of 15 fall 1967, 10 winter 1967 spring 1968, and 13 summer 1968 plankton samples at index station (Tahoe Pines) of Goldman (1974). 1968, 13 October 1987 VanLandingham: Lake Tahoe 567 SOUTH STATION 5 LAKE TAHOE 5/16/1967 7/3/1973 0 50% 0 50% SOUTH LAKE TAHOE ZEPHYR COVE LOGAN SHOALS 10/27/1985 10/27/1985 10/27/1985 50% 0 30% 0 50% 1 1 1 1 1 1 1 1 X Acidobiontic i f ] 1 1 1 Acidophilous m ■ 1 1 Indifferent ■■ 1 ^^H 1 ■ Alkaliphilous ^^^^H 1 ■1 ^PPPH ^^H r Alkalibiontic 1 1 1 1 ■ ^^^^ 1 1 1 II 1 1 Unknown or other ^^^^H JHK I ^p ilair i a. Polysaprobic or Saprobiontic | 1 1 1 r Mesosaprobic | 1 I alpha range (strong) | 1 1 1 beta range (weak) ^H 1 L Oligosaprobic iBH ■ j^i 1 Saprophilic | | | ■ ri 1 ipi Saproxenous pHH^ ! F ■ r^ Katharobic or Saprophobic | | | LL ! n 1 1 1 Unknovn or other ^^^^| H IPPVPB t s. II 1 Polytrophic | | | IT MM r Eutrophic ■ 1 ■pi ■ ■p m" - !■■ Mesotrophic W I , 3^ m m r 'J Oligotrophic n 1 ' 1 I ff Dystrophic 1 1 1 i L 1 1 1 1 1 Unknown or other ^^^^H ■ ~^^^M ipE: -m^^ i 2 Euhalobous or Polyhalobous | r Uesohalobous | 1 alpha range (strong) [ 1 f beta range (weak) | 1 Oligohalobous | F" 1 II Halophilous T 1 1 1 Indifferent BMBH^H u^^^ w ■ Halophobous | X Euryhalobous or Euryhaline I 1 1 1 1 1 Unknown or other "PHHHT 1 r IHH dMii g Limnobiontic 1 1 1 1 r ii 1 ^M Lionophilous ■1 1 1 1 -ft 1 Indifferent ■ 1 1^ ■1 Mi ■pv^ ■1 Hheophilous 1 I w TTT W df T Rheobiontic 1 1 r 1 1 1 , T Unknown or other f^HH 1 h-|^^ II ■1 i 5 Benthic | | | 1 1 L 1 E T T Lentic Lakes & Ponds ^^^| w^m. ■ ■■ ■■ Bogs or Swamps 1 [ 1 Lotic Crenophilous (general) r Irenophilous (thermal) L 1 Rivers I Streams ■ ■ ■ 1 Aerophilous or Terrestrial 1 n r Estuarine | LL L Littoral (Literal) U ■1 ■I ■1 Neritic Oceanic Eurytopic or Euryecious 1 L 1 Unknown or other ^^^^^^H ^m IIH'^ ■ L ^m H i 3 85 Planktonic (Pelagic) 1 ■ ipp^ diV 1 ■^ Euplanktonic L L r Tychoplanktonic | ■ I 1 Periphytic (Aufwuchs) ■ 1 1 ■ Epipelic 1 1 IT Epilithic 1 k J Epiphytic ■ 1 ■ Other Periphytic 1 t ji Unknown or other ■■^ ■ 1 ^m 10 a (Winter Tr ■ X 1 ■^ Spring VB ■l - - 1 - - II 1 Summer r I ir 1 ■ Fall 1 1 1 1 5 a Euthernal | p 1 1 1 1 Irlesothermal k -LL 1 ^■■■n; Oligothermal ■■1 iJlVi Tl Stenothermal 1 IT Metatherraal 1 -- LL^ Eurythernal 1 1 1 !■ IIJHE i Unknown or other Ihu ! 1 u J J J 1 I 1 Ti J J ■ ■ ■ I L _r 1 I^^HL-L — Fig. 4. Spectral histograms of diatom species percentages from the VanLandingham survey of 1967-1985; all stations were planktonic except Logan Shoals, which was periphytonic. 568 Great Basin Naturalist Vol. 47, No. 4 1974). One of the advantages of a comprehen- sive algal data synthesis like CAESARS is that the general and specific habitat spectra in con- junction with the nutrient and saprobian spec- tra can be helpful in determining if an alga is absent from an assemblage because of lack of suitable physical habitat or because of adverse water chemistry. Any artificial, comprehen- sive system of data synthesis involving the classification of ecological tendencies of algae is bound to have conspicuous deficiencies. Stoermer (1984) presents an excellent and ob- jective discussion of some of these difficulties. Samples California-Nevada-FWPCA Survey Plankton. — Plankton grab samples were taken during this cooperative investigation from the following five stations on 27-30 April, 17-19 August, 28-30 September 1965; 25-27 January, 27-29 April, 16-18 August, 14-17 November 1966; and 6-8 February 1967 (California Department of Water Re- sources 1966, 1967). Histograms were made from diatom species percentages for the 6-8 February 1967 samples (Fig. 1). Station 1 is about 1 km north of the mouth of the Upper Truckee River and at the edge of the southerly shelf of Lake Tahoe, El Dorado Co., California. The station is representative of conditions in shallower waters near an ex- tensively developed residential and resort area and is responsive to surface inflow from tributary streams. Bottom depth is 7.5 m. Magnetic bearings from Station 1 are N 4° E to Cave Rock and S 86° E to the building on Globin's Pier at Al Tahoe (Fig. 5). Station 2 is about 1.3 km northeast of the buoy at the mouth of Emerald Bay in El Dorado Co., California. The station is repre- sentative of conditions in deep waters and may be affected by inflows through Emerald Bay. Bottom depth is 345 m. Magnetic bear- ings from station are S 30° W to buoy "2" at the mouth of Emerald Bay and S 86° E to the building at Globin's Pier in Al Tahoe (Fig. 5). Station 3 is 8.5 km south of Stateline Point and due west from Secret Harbor. The station is representative of waters in the deepest part of the lake and is at the eastern boundary of Placer Co., California. Bottom depth is 471 m. Magnetic bearings from Station 3 are N 8° W to Gal-Neva Lodge and S 67° W to Dead- man Point on the Nevada shore (Fig. 5). Station 3A (alternate station) is 5 km south- west of South Point, near the confluence of the Placer-El Dorado county line (California) with the Nevada state boundary. The station is representative of waters in the deepest part of the lake. Bottom depth is 465 m. Magnetic bearings from Station 3A are N 15° W to Gal- Neva Lodge and S 64° E to the Sahara Hotel at Stateline (Fig. 5). Station 4 is 180 m from shore at a point 1.3 km west of Incline Creek, Washoe Co., Ne- vada. The station is representative of shallow waters in Crystal Bay and is responsive to inflow from Incline Greek. Bottom depth is 6 m (Fig. 5). Station 5 is 1.3 km easterly from the dam at the lake outlet on the Truckee River at Tahoe City, Placer Co., California. The station is representative of shallow waters at the north- west corner of the lake and of the water flow- ing out of the lake. Bottom depth is 9 m. Magnetic bearings from Station 3 are N 38° W to the Chevron sign at Tahoe City Boat Works and N 20° E to the United States Coast Guard radio tower (Fig. 5). Periphyton. — Station 5 also was used for periphyton sampling. The bottom sample from this station, representing 20 October 1965-25 January 1968, was selected for com- parison with four surface periphyton samples that were taken from the pier at the United States Coast Guard Station (2.9 km northeast of Tahoe City) at Lake Forest, Placer Co., California. Surface samples represented the time intervals of 2-20 December 1966, 20 December 1966-4 January 1967, 4-12 Janu- ary 1967, and 18 January-13 February 1967. Spectral histograms were compiled from di- atom species proportional counts from these five periphyton samples (Fig. 2). Permanent hyrax slides of both periphyton and planktonic samples from the stations mentioned above have been deposited at the United States Na- tional Museum of Natural History, Washing- ton, D.C. Goldman (1974) Survey Plankton. — In Goldman's (1974) compre- hensive study of the eutrophication of Lake Tahoe from 1967 through 1971, samples were taken on 115 different days from the desig- nated index station at Tahoe Pines (in the Blackwood Creek-Madden Creek interfluve October 1987 VanLandingham: Lake Tahoe 569 )• SOUTH LAKE • ' TAHOE \ KILOMETERS Fig. 5. Map of Lake Tahoe showing sites mentioned in this paper. Circled numbers represent sample stations of the California-Nevada-FWPCA survey. 570 Great Basin Naturalist Vol. 47, No. 4 area, Placer Co., California) (Fig. 5). Ap- pendix C of that publication gave a tabulation of the average number of individuals (cells/ml) of each phytoplankton species for the entire 105-m water column at this station. The fall 1967 through summer 1968 sequence, repre- sented by 51 sampling days, was used for plot- ting histograms (Fig. 3). Results from fall 1968 through fall 1971 sequences of samples were very similar and therefore were not figured. The fall 1967 spectra were plotted by totaling the average number of individuals of each diatom species for the entire 105-m water column for the 15-day fall 1967 sequence and then calculating the percentage of each di- atom species in the total diatom community for that season. In the same manner, spectral histograms were generated for the 10 samples from the winter of 1967-1968, the 13 samples from the spring of 1968, and the 13 samples from the summer of 1968 (Fig. 3). Periphyton. — Goldman (1974) showed the relative proportions of periphyton (mostly di- atoms) for the intervals of 24 June-30 Septem- ber 1970 and 1 October 1970-2 May 1971 from several stations around Lake Tahoe in the vicinity of the following localitites: Gen- eral Creek, Emerald Bay, and Tahoe Keys in El Dorado Co., California; Zephyr Cove and Cave Rock in Douglas Co., Nevada; Skunk Harbor in Carson City, Nevada; Incline Creek and Crystal Bay in Washoe Co., Ne- vada; and Dollar Point (Lake Forest), Ward Creek, and Tahoe Pines in Placer Co., Cali- fornia (Fig. 5). These samples are discussed below under Observations. VanLandingham Survey of 1967-1985 Plankton. — My own survey of the diatoms of Lake Tahoe began with plankton samples from Tahoe City (Station 5) on 28 March 1967 and continued with samples at irregular times from this and three other stations until 28 October 1985. Because of possible differences in species interpretations in the California- Nevada-FWPCA joint survey, several sam- ples were sent to various investigators and laboratories for determinations, comparisons, and verifications. The Academy of Natural Sciences of Philadelphia laboratory and I ex- amined the 16 May 1967 plankton sample from Station 5 (Fig. 4). Our species determi- nations were very similar. Permanent hyrax slides are deposited at the Geology Depart- ment, California Academy of Sciences, San Francisco. The samples were prepared for mi- croscopic examination and species propor- tional analysis following VanLandingham (1976). Since July 1973, sampling has been restricted to three stations in the southeast portion of the lake: Station A (South Lake Tahoe) is about 1 km west of the boat harbor near the South Lake Tahoe Recreation Area, El Dorado Co. , Cali- fornia (Fig. 5). This station was chosen for its close proximity to the most densely populated and highly developed region of the lake. Spec- tral histogram results from two samples sepa- rated by a 12-year span from this station can be compared (Fig. 4). Station B (Zephyr Cove) is 1.5 km northeast of Zephyr Point at the Zephyr Cove pier, Douglas Co., Nevada (Fig. 5). Although there are some recreational and commercial facili- ties in the area, it is not heavily populated. A series of histograms was plotted for the 27 October 1985 sample from this station (Fig. 4). Periphyton. — Station C (Logan Shoals) is 2.5 km north of Cave Rock and near the mouth of Logan House Creek in Douglas Co., Ne- vada (Fig. 5). This is one of the few remaining, relatively unspoiled areas on Lake Tahoe. It is the only station encountered in this study that I have found to be oligotrophic more often than mesotrophic and/or eutrophic on the ba- sis of indicator algae. At this station periphy- ton was scraped at irregular intervals from plants and large boulders at the water's edge. The spectral histograms were composed for a recent sample from 27 October 1985 (Fig. 4). Observations California-Nevada-FWPCA Survey Phytoplankton. — The 27-30 April 1965 and 25-27 January 1966 plankton diatoms from samples of the California-Nevada- FWPCA joint investigation indicated a pro- nounced mesotrophic character for the entire lake. The prominence of Sijnedra nana Meist., an indicator of mesotrophy (Cody 1978), was responsible for the strong mesotrophic nature of these samples. The re- maining dominant species, all of which were eutrophic (and/or mesotrophic) indicators ex- cept Cyclotella bodanica Eul. ex Grun. and Stephanodiscus invisitatus Hohn & Hell., October 1987 VanLandingham: Lake Tahoe 571 accounted for a less pronounced but conspicu- ous eutrophic character. The percentages of the most dominant species from the 27-30 April 1965 samples were as follows: Station 1, Fragilaria crotonensis 52, Synedra nana 21, Stephanodiscus invisitatus 4, and Nitzschia acicula ris (Kutz.) W . Sm. 3; Station 2, S. nana 39, Asterionella formosa Hass. 29, F. cro- tonensis 20, and N. acicularis 6; Station 3, F. crotonensis 47, S. nana 37, N. acicularis 4, and A. formosa 3; Station 4, S. nana 31, F. crotonensis 30, F. construens (Ehr.) Grun. 3, and Arnphiprora (Entomoneis) paludosa W. Sm. 3; and Station 5, S. nana 41, N. acicularis 11, and F. crotonensis 4. The dominant spe- cies from the 25-27 January 1966 samples were as follows: Station 1, F. crotonensis 48, S. nana 33, F. construens 4, and Melosira italica (Ehr.) Kiitz. 4; Station 2, S. nana 53, F. crotonensis 15, M. italica 8, and F. pinnata 5; Station 3A, S. nana 59, F. crotonensis 21, A. formosa 6, and N. acicidaris 3; Station 4, F. crotonensis 43, S. nana 35, F. construens 6, and A. formosa 5, and Station 5, F. crotonen- sis 48, S. nana 23, C. hodanica 8, and M. italica 3. Eutrophic and/or meso-trophic di- atoms prevailed at all five stations in the plankton samples collected on 17-19 August and 28-30 September 1965. Only Sta-tion 2 (at the August sampling) showed any marked tendency toward oligotrophy. A similar trend toward mesotrophy in the winter can be seen in the first three stations on 6-8 February 1967 (see nutrient spectrum, Fig. 1). Station 4 (Fig. 1) was anomalous and showed an oligotrophic nature that was found rarely in the plankton. In all of these samples Cyclotella hodanica was dominant, but Syne- dra nana, Fragilaria crotonensis, and many other mesotrophic and eutrophic indicators were important. The nutrient spectra of all stations (Fig. 1) correlate well with both the saprobian and pH spectra. Mesotrophic wa- ters usually are concomitant with oligosapro- bic and/or saproxenous conditions in the saprobian spectrum and with indifference in the pH spectrum. Oligohalobous indifference in the halobion spectrum is to be expected in subalpine lakes. The prominent limnophilous element in the current spectrum and the prominent lake and pond category in the gen- eral habitat spectrum suggest that the plank- ton at this time of the year is mostly indige- nous to the lake and not carried in from streams. The specific habitat spectrum con- firmed the planktonic nature of the samples. Because the seasonal distribution of most of these planktonic diatoms is imperfectly known, the seasonal spectrum gave inconclu- sive results. VanLandingham (1964) and oth- ers have pointed out that temperature and nutrients are more important in diatom distri- bution than seasonal influence. The strong oligothermal character of the temperature spectrum is normal and reflects the cold- water characteristics which would be ex- pected in the plankton of a large, subalpine lake in the winter. On the other hand, sam- ples from all of the periphyton stations from cold times of the year (late fall-winter) were eurythermal (widely tolerant of temperature changes) (Fig. 2). Eutrophy in the nutrient spectrum nor- mally is correlative with oligosaprobic to weak mesosaprobic conditions in the saprobian spectrum and with alkaliphilous conditions in the pH spectrum. Spring plankton samples of 27-29 April 1966 demonstrated this very well as did periphyton samples (Fig. 2) and the Tahoe Pines plankton samples (Fig. 3). Fragi- laria crotonensis was the most abundant di- atom at all stations (composing 98% of the assemblage at Station 2) in the 27-29 April 1966 plankton samples. Although F. cro- tonensis was less important (becoming more subordinant to Fragilaria construens and F. pinnata) in the summer (16-18 August) sam- ples and the fall (14-17 November) samples, the conspicuous eutrophic conditions re- mained. A sample from a depth of 25 m was taken at Station 2 in the summer to supple- ment the regular 3-m sample from that sta- tion. The two most dominant diatoms, Cy- clotella meneghiniana Kiitz. and C. atomus Hust., from the deep sample were prominent eutrophic indicators and accounted for 39% and 30%, respectively, of the total diatom community. Periphyton. — It is noteworthy that the mesotrophic trend found in diatoms of the plankton samples of 6-8 February 1967 (Fig. 1), 25-27 January 1968, and 27-30 April 1965 did not occur in any of the periphyton samples (Fig. 2). Fragilaria construens, F. pinnata, Synedra vaucheriae Kiitz., and Nitzschia kuetzingiana Hilse (all of which are character- istic of eutrophic waters) accounted for most of the prominent eutrophic aspect of all of these 572 Great Basin Naturalist Vol. 47, No. 4 periphyton samples; the last of these species is a diagnostic eutrophic indicator (Krieger 1927, J0rgensen 1948, Cleve-Euler 1953, Kolbe 1953, Van der Werff and Huls 1957- 1974, Cholnoky 1968, Schoeman 1973, Moghadam 1976, Caljon 1983). In large lakes it is not unusual to find planktonic taxa com- posing a large part of the periphyton assem- blages, hence the large proportion of plankton in the specific habitat spectrum of all the peri- phyton samples (Fig. 2). This phenomenon also can be seen in the specific habitat spec- trum of the Logan Shoals periphyton sample of the VanLandingham survey (Fig. 4). Goldman (1974) Survey Phytoplankton. — Goldman (1974) stated in his conclusions, Cyclotella bodanica and Melosira crenulata are dominant centric diatoms while Fragilaria crotonensis is the most important pennate. These three ohgotrophic forms ac- count for about 80% of the phytoplankton biomass throughout the year. It is likely that only one of these, C. bodanica , is an ohgotrophic form (Hustedt 1930, Van der Werff and Huls 1957-1974, Tamas 1964, Hutchinson 1967, Duthie and Sreenivasa 1971, Sreenivasa and Duthie 1973, Aimer et al. 1974, Rosen 1981). However, there are many reports of it in eutrophic or mesotrophic waters, such as Lipscomb (1966). On the other hand, Hillard (1959) noted that a slight pulse in C. bodanica corresponded with eutrophy. Recent taxonomic research suggests that C. bodanica may grade into C. comta Fricke. The report on centric diatoms of Lake Tahoe by Mahood et al. (1984) discussed C. comta in detail but did not mention C. bodanica. There is no clear consensus in the numerous refer- ences in CAESARS that shows C. comta to be correlative with any particular trophic status. It is probably eurytrophic (indifferent to inorganic nutrient content). Melosira crenulata is a junior synonym of M. italica, which most authorities consider to be a eutrophic indicator. Mahood et al. (1984) state that M. italica is alkaliphilous and mesotrophic. Reynolds (1984) is one of the few references that gives it a distinct mesotrophic designation. Although Van der Werff and Huls (1957-1974) and Bradbury (1972a) indi- cated that M. italica is mesotrophic, they also implied that its range extended into the ohg- otrophic and/or eutrophic zones. However, if it is indeed mesotrophic, the probability of its being alkaliphilous is subject to serious ques- tion. It is more likely that it is not mesotrophic but alkaliphilous and eutrophic. If there is any propensity for mesotrophic diatoms to corre- late with a position in the pH spectrum, it is with indifference (occurrence around pH 7), which is to be expected if one follows the explanations of Fjerdingstad (1965a), Sparling and Nalewajko (1970), and VanLandingham (1976). Although there have been indications that M. italica may be acidophilous (Niessen 1956, Round 1961), 17 CAESARS references categorize it as alkaliphilous (Foged 1958, 1959, 1976, 1980a, Maillard 1959, Liebmann 1962, Cholnokv 1968, 1970a, VanLanding- ham 1970, Ehrjich 1973, Gasse 1975, Kacz- marska 1976, Rehakova 1976, Moreira and Moreira 1982, 1984, Gasse and Tekaia 1983, Dixit and Dickman 1986; 4 as alkaliphilous to indifferent (Hustedt 1957, Gasse 1972, Lowe 1974, Foged 1978); and 8 as indifferent (Foged 1954, 1957, 1970, Haworth 1969, Messina- Allen and VanLandingham 1970, Baudrimont 1974, Khursevich 1976, Del Prete and Schofield 1981). If M. italica is conceded to be alkaliphilous, it is much more likely to have the associated eutrophic correlation found with over 100 commonly occurring diatoms. Only Round (1960), Cholnoky (1970a), Stock- ner (1971), and Weber (1973) indicated that M. italica might be characteristic of ohg- otrophic waters, while there is much more agreement concerning its correlation with eu- trophic waters (Krieger 1927, Hustedt 1930, 1942, Brockmann 1935, Frenguelli and Cor- dini 1937, Foged 1951, 1959, Bourrelly and Manguin 1952, Jiirnefelt 1952, Guermeur 1954, Messina-Allen and VanLandingham 1970, VanLandingham 1970, Baudrimont 1974, Planas 1975, Gasse 1975, and Negoro 1981). Mesohalobous (characterized by brack- ish water, 0.5-3.0% salt) organisms are very rare in alpine and subalpine lakes. The state- ment of Mahood et al. (1984) that M. italica is mesohalobous seems doubtful in view of the evidence that only Van der WerflF and Huls (1957-1974) reported it from the weak mesa- halobous zone (but also in the oligohalobous zone). If M. italica is truly mesohalobous, why would it be so common in a high, subalpine lake, such as Lake Tahoe? There is even some consensus that M. italica has a negative corre- lation with salt content since Cleve-Euler October 1987 VanLandingham: Lake Tahoe 573 (1951), Hustedt (1957), Palik (1958), and Bau- drimont (1974) regarded it as halophobous (salt-deficient waters) and Gasse (1972), Lowe (1974), and Rehakova (1976) as halophobous to indifferent. However, the greatest consensus is that it is ohgohalobous (indifferent): Kolbe (1927, 1953), Cholnokv (1929), Brockmann (1954), Foged (1954, 1957, 1959, 1970, 1976, 1978, 1980a, 1982), Messina-Allen and Van- Landingham (1970), VanLandingham (1970), Gasse (1975), Khursevich (1976), and Moreira and Moreira (1982). In the examination of over 4,000 refer- ences, no indication was found that Fragilaria crotonensis was clearly diagnostic of oligo- trophic waters, although it is sometimes found in large numbers in those waters. Beeton (1965), Stoermer and Yang (1970), Stoermer et al. (1974), Stoermer and Ladewski (1976), and Grimes et al. (1984) suggested that it ranged from oligotrophic to eutrophic. Van der Wei-ff'and Huls (1957-1974) gave a dys- trophic to eutrophic (and/or hypertrophic) range. Teiling (1955), Rawson (1956), Patrick and Reimer (1966), Tarapchak and Stoermer (1976), and Gerrath et al. (1980) considered it to be most prominent in mesotrophic wa- ters. It has been described as mesotrophic- eutrophic by Cleve-Euler (1953), Round and Brook (1959), and Lowe (1974). But the great- est agreement is in favor of its eutrophic ten- dency: Krieger (1927), Hustedt (1930), J0rgensen (1948), Margalef (1957), Hutchin- son (1967), Stockner and Benson (1967), Lehn (1969), Frey (1969), Vollenweider (1970), Stockner (1971), Stoermer et al. (1971), Stadelmann (1971), Bradbury (1972a, 1972b), Haworth (1972a), Nikalovev and Petrova (1978), Burns and Mitchell (1974), Planas (1975), Gorham and Sanger (1976), Holtan (1978), Bailey and Davis (1978), Cassie (1979), Cassie and Freeman (1980), Rosen (1981), Ne- goro (1981), Mason (1981), Brugam and Pat- terson (1983), Reynolds (1984), Haff'ner et al. (1984), and Engstrom et al. (1985). In addi- tion, Stockner (1972) stated that it correlates well with domestic sewage discharge into lakes. Stoermer et al. (1974) and Bradbury (1975) advocate that it is eurytopic, as do Duthie and Sreenivasa (1971), but with ac- knowledgment of its eutrophic character. Fragilaria crotonensis requires for optimal growth more than 20 |jig P 1 ' (Fogg 1973). L0vstad (1984) indicated a sharp drop in the development of F. crotonensis at concentra- tions of less than 16 |xg P 1^ in eutrophic Lake Jaren in April and May 1976. Goldman (1974: 72) stated that F. crotonensis "is now the dom- inant type in Lake Tahoe, both in biomass and numbers. " Such a diatom (which, according to 21 references supplied by CAESARS, is found only in the oligosaprobic and/or weak meso- saprobic zones) seems out of place in such large numbers in a body of water so oligo- trophic as Lake Tahoe is alleged to be. It is known that F. crotonensis has a pro- nounced correlation with alkaliphilous condi- tions (optimum development above pH 7) (J0rgensen 1948, Foged 1948, 1953, 1954, 1958, 1959, 1968, 1969, 1970, 1978, 1980a, 1980b, 1982, Hustedt 1957, Van der Werff" and Huls 1957-1974, Round 1964, Patrick et al. 1968, Cholnokv 1968, Stoermer et al. 1971, Besch et al 1972, Del Prete and Schofield 1981, Brugam and Patterson 1983, and Dixit and Dickman 1986). Fjerdingstad (1965a), Sparling and Nalewajko (1970), and VanLandingham (1976, 1982), among many others, have pointed out that definite correla- tions can be made between trophic status of lakes and their pH: eutrophic habitats gener- ally correspond with a high pH (above 7), mesotrophic habitats generally correspond with an intermediate or circumneutral pH, and oligotrophic habitats generally corre- spond with a low pH (below 7). Studies from 1951 to 1967 showed pH values from the lake to be invariably above 7, in one instance reaching a maximum of 8.4 (California De- partment of Water Resources 1967). None of the samples examined in mv study of 1967-1985 ever had a pH below 7.2. According to Goldman (1974: 131), the five most dominant species of phytoplankton at the index station (Tahoe Pines) for 1967-1969 (in order of importance) were Fragilaria cro- tonensis, Melosira crenulata ( = M. italica), Fragilaria pinnata, Stephanodiscus astraea (Ehr.) Grun., and Cyclotella hodanica. Al- though the trophic disposition of F. pinnata is considered to be oligotrophic or mesotrophic through eutrophic (Van der Werff and Huls 1957-1974, Stoermer et al. 1971) and oligo- trophic (Beeton 1965, Baudrimont 1974), the greatest number of authorities deem it to be eutrophic (Hustedt 1937, 1938, j0rgensen 1948, Foged 1951, 1959, Bourrelly and Man- guin 1952, Ross 1952, Cleve-Euler 1953, 574 Great Basin Naturalist Vol. 47, No. 4 Messina-Allen and VanLandingham 1970, VanLandingham 1970, Gasse 1972, 1974a, 1974b, Lowe 1974, and Caljon 1983). Stephanodiscus astraea and its varieties are some of the most diagnostic of all indicators of eutrophy. According to CAESARS, appar- ently no authorities judge S. astraea to be exclusively oligotrophic. Cleve-Euler (1951), Patrick (1956), and Werff and Huls (1957- 1974) consider the trophic range to be oligo- trophic and/or mesotrophic through eu- trophic, but most investigators agree that it is eutrophic (Krieger 1927, Hustedt 1930, 1942, 1949, J0rgensen 1948, Foged 1948, 1951, 1953, 1959, Bourrelly and Manguin 1952, Kolbe 1953, Guermer 1954, Brockmann 1954, Round and Brook 1959, Hutchinson 1967, Gasse 1969, 1972, 1974b, 1975, Haworth 1972b, Moreira 1975, Stoermer and Ladewski 1976, and Mason 1981). Mahood et al. (1984) did not mention S. astraea but did comment on Stephanodiscus alpinus Hust., a closely related form. It is highly unlikely that S. alpinus is alkalibiontic, as they claim. Alka- libiontic species are rare among the diatoms. Out of a total of 2,900 diatom taxa, CAESARS reveals that no more than two dozen are defi- nite alkalibionts, none of which are centrics except Stephanodiscus duhius (Fricke) Hust. Stephanodiscus alpinus may be eutrophic as Hohn (1969) and Mahood et al. (1984) imply. However, Ayers et al. (1967) indicate that it might be oligotrophic, and Tarapchak and Stoermer (1976) note maximum abundance in the mesotrophic zone. Although it occurs in very oligotrophic lakes, it seems to become more abundant with moderate degrees of eu- trophication (Stoermer 1978, Hakansson and Stoermer 1984). Goldman (1974: appendix) shows very con- spicuous pulses oi Sijnedra radians Kiitz. ( = Synedra acus var. radians) at the index sta- tion in summer 1969, spring 1970, and winter, spring, and fall 1971. Apparently only Whit- ford and Kim (1971) found S. radians to be oligotrophic. It is thought to be mesotrophic (Ayers et al. 1967), mesotrophic through eu- trophic (Cleve-Euler 1953, Van der Werff and Huls 1957-1974), and eutrophic (j0rgensen 1948, Lowe 1974). According to Goldman (1974), on 13 May 1970 Microcystis (Polycystis) aeruginosa Kiitz. had a total of 5.76 individuals/ml for the entire 105-m water column at Tahoe Pines. At that time, M. aeruginosa composed 5.1% of the total phytoplankton population and was outnumbered only by the diatoms Melosira italica ( = M. cremdata), Asterionella for- mosa, and Fragilaria crotonensis. Evidently there are no reports of M. aeruginosa being found exclusively in oligotrophic waters. It is well known as a waterbloom-forming blue- green alga. Although there are sporadic re- ports of this taxon on certain occasions from mesotrophic waters (Mabille 1956, Rawson 1956), it nearly always is found in close corre- lation with eutrophic and/or mesotrophic wa- ters (Krieger 1927, Redeke 1935, Nygaard 1949, F^jerdingstad 1950, GerlofF et al. 1952, Jarnefelt 1952, Teiling 1955, Round and Brook 1959, Prescott 1962, Lund 1962, Bee- ton 1965, Cairns et al. 1972, Peelen 1975, Nikolayev and Petrova 1978, Hickman 1979, Cassie and Freeman 1980, Parra et al. 1980, Takahashi et al. 1981, Rosen 1981, Okada et al. 1981, Coardetal. 1983, Nicklisch and Kohl 1983, Caljon 1983, Caceres and Reynolds 1984, Takamura and Yasuno 1984, Reynolds 1984). Dinohryon sertularia Ehr. made up a con- siderable portion of the total algae community on at least three occasions at Tahoe Pines, having a total of 38.34, 18.99, and 21.42 indi- viduals/ml for the entire 105-m water column on 9 and 16 May 1968 and 24 July 1969, re- spectively (Goldman 1974). On these three occasions, D. sertularia was an important sub- dominant, composing 18, 10, and 28.8%, re- spectively, of the total population. In the same publication (Goldman 1974: Fig. 2), ap- parently D. setiularia is referred to as Dino- hryon sociale Ehr. Both of these taxa are eu- trophic. Such investigators as Krieger (1927), Huber-Pestalozzi (1941), Meyer and Brook (1969), and Gerrath et al. (1980) believe that D. sertularia occurs under eutrophic condi- tions, while Krieger (1927) and Huber- Pestalozzi (1941) hold the same opinion for D. sociale. Sphaerocystis schroeteri Chod. was the dominant algal species on nine different occa- sions in the fall of 1967 at the Tahoe Pines station (Goldman 1974). In spite of the fact that it is occasionally found in oligotrophic lakes (Aimer et al. 1974), many such writers as Meyers and Brook (1968) describe S. schroe- teri as eutrophic, whereas Reynolds (1984) contends that it is mesotrophic. October 1987 VanLandingham: LakeTahoe 575 There is good evidence that in some areas of Lake Tahoe the algae display an oligotrophic tendency at certain times. Goldman (1974: 131) found Cyclotalla stelligera to be uncom- mon at the index station (Tahoe Pines) in 1967-1971 but to be present in large numbers in midlake plankton samples in 1972-1973. CAESARS provides a strong opinion that C. stelligera is typical of oligotrophic waters: J0rgensen (1948), Cleve-Euler (1951), Hutch- inson (1967). Stockner (1971), Schnitzler (1971), Holland and Beeton (1972), Croome and Tyler (1973), Burns and Mitchell (1974), Lowe (1976), Bailey and Davis (1978), Cassie and Freeman (1980), Smol et al. (1983), Schelske (1984), and Engstrom et al. (1985). Smedman (1969), Bradbury (1972b), and Tarapchak and Stoermer (1974) advocate dystrophic-oligotrophic, oligotrophic-meso- trophic, and mesotrophic categories, respec- tively, while Duthie and Sreenivasa (1971) suggest it is "eurytopic-eutrophic." Onlv Cholnoky (1968, 1970b), Lowe (1974), and Moghadam (1976) support the contention of Mahood et al. (1984) that it is eutrophic. Sewage export from the Tahoe basin in recent years may be responsible for the increase of such oligotrophic indicators as C. stelligera at various places in the lake. On the other hand, most of the evidence supplied by the Van- Landingham survey of the years 1967-1985 suggests that the propensity toward mesotro- phy (or even eutrophy) displayed by the most dominant diatoms is still strong over much of the lake. Periphyton. — In spite of the fact that the littoral zone contributes a small portion of the total primary productivity and that the lake has great area and depth, the importance of the littoral areas and periphyton cannot be overlooked in a comprehensive evaluation of the lake's trophic characteristics. The seven most dominant species in the periphyton from 11 stations around Lake Tahoe between 1 Oc- tober 1970 and 2 May 1971 were: Synedra actinastroides Lemm., Fragilaria crotonen- sis, Gomphonema parvulum Kiitz. , Cyclotella hodanica, Synedra ulna, Gomphoneis her- culeana (Ehr.) Cl., and Melosira cremdata (Goldman 1974: Fig. 55). CAESARS indicates that only C. hodanica is predominantly oligo- trophic; all of the rest are eutrophic, except G. herculeana. The six most important diatoms in the periphyton from 10 stations around Lake Tahoe between 24 June and 30 Septem- ber 1970 were: Epithemia argus (Ehr.) Kiitz., Rhopalodia gibba (Ehr.) O. Miill., Synedra ulna, Cynibella ventricosa Ag., Navicula au- rora Sov., and Fragilaria capucina Desm., none of which clearly indicates oligotrophic conditions and most of which are eutrophic indicators. Goldman (1974) notes that F. ca- pucina was a dominant species in the periphy- ton of the summer of 1971 only off the Upper Truckee River mouth and in Emerald Bay, both of which are noted for high productivity. Many authorities think that F. capucina is a good enrichment indicator. However, Schroder (1939) states that it is not particu- larly sensitive to pollution. Only Rawson (1956) and Beeton (1965) place it directly in the oligotrophic zone. Cleve-Euler (1953) and Van der Werff and Huls (1957- 1974) assign it to the dystrophic through mesotrophic and/or eutrophic zones. The range given by Round and Brook (1959) is mesotrophic-eutrophic. However, nearly all authorities regarded it as eutrophic: Krieger (1927), Hustedt(1930, 1938, 1942), j0rgensen (1948), Foged (1951, 1959), Bourrelly and Manguin (1952), Holland (1965), Gasse (1969), Bradbury (1972b), Stoermer et al. (1974), Lowe (1974), Stoermer and Ladewski (1976), Tarapchak and Stoermer (1976), and Bailey and Davis (1978). VanLandingham Survey of 1967-1985 Phytoplankton. — Many of my own sam- ples from Tahoe City (station 5 of the Califor- nia-Nevada-FWPCA survey) demonstrated marked fluctuations in the histograms of all spectra at different times of the year. How- ever, mesotrophic and/or eutrophic condi- tions always predominated in the nutrient spectrum. In the 16 May 1967 plankton sam- ple from station 5 (Fig. 4), Synedra nana (25% of the total) was responsible for most of the mesotrophic manifestation, and Fragilaria crotonensis (20% of the total) accounted for most of the eutrophic manifestation. This sample, which comes from the northeastern portion of the lake, is included for comparison with samples from the three stations (South Lake Tahoe, Zephyr Cove, and Logan Shoals) in the southeastern portion of the lake and with other results from station 5 (Figs. 1-2). Spectral histograms of diatom species per- centages from plankton samples at the South 576 Great Basin Naturalist Vol. 47, No. 4 Lake Tahoe station on 3 July 1973 and 27 October 1985 can be compared in Figure 4. Other samples were taken at South Lake Tahoe during the long interval represented by these two samples, but their histograms were not figured because of their great similarities. After a period of over 12 years, one can see the similarity of the spectra in these two samples and the eutrophic aspects of both. The dimin- ishing of the eutrophic category in the 1985 sample in relation to the 1973 sample may be a result of sewage export from the Tahoe basin in recent years. The planktonic assemblage from Zephyr Cove on 27 October 1985 was very typical of that station and exhibited the usual eutrophic characteristics (Fig. 4); counts for the diatoms were about 20 cells/ml. Cy- clotella glornerata Bach., Achnanthes lance- olata, Nitzschia linearis (Ag.) W. Sm., and Cocconeis diminuta Pant, were the dominant taxa, the last of which is a diagnostic mesotrophic to eutrophic indicator (Hustedt 1938, J0rgensen 1948, Cleve-Euler 1953, Foged 1957). Periphyton. — After studying hundreds of samples over a period of 18 years from many stations in the three independent surveys of Lake Tahoe, I have found Logan Shoals to be the only station (planktonic or periphytonic) in which the indicator algae suggest general oligotrophic conditions more often than mesotrophic and/or eutrophic (Fig. 4). Conclusions The slight increase in recent years in oligo- trophic algae, such as Cijclotella stelligera and Achnanthes tninutissiina, and the correspond- ing slight decrease in the dominant mesotrophic and eutrophic algae at various places in the lake seem to correlate well with the export of sewage from the Tahoe basin. This situation bears testimony to the sensitiv- ity of the algae as indicators. However, the strong mesotrophic-eutrophic trend, which was indicated by the algae from about 1965 until about 1973 or 1974, still continues today, although probably to a lesser degree. More- over, repeated spills of raw and partially treated sewage have been indicated ade- quately by the microalgae populations and other modes of observation to such an extent that the United States Environmental Protec- tion Agency and California's regional water quality control board have duly noted that the Lake Tahoe water reuse system for recycling sewage into drinking water is no longer feasi- ble (U.S. Water News 1986). It could be claimed that the persistence and prominence of a whole suite of characteristically eutrophic (and/or mesotrophic) diatoms in a lake tradi- tionally thought to be oligotrophic attests to the admonition that we should reexamine ei- ther the lake or the validity of the algal indica- tor concept (or both). Can algal communities be valid indicators of the trophic status of a lake or do physical and chemical factors provide the only reliable clues to deciphering trophic status? If the former is true, then our traditional opinions about Lake Tahoe will have to change. If the latter is true, then there should be dynamic changes in limnological thought. In either case, it seems prudent to maintain philosophical objectivity and con- sider all aspects of biological, physical, and chemical factors in trophic assessment, even if they seem to be contradictory. If it is granted that Lake Tahoe is not highly anomalous, then undoubtedly it is somewhat less "ultra-oligo- trophic " than the water chemists and physical limnologists would advocate, and probably the indicative diatoms and other algae are somewhat less accurate than the diatomists and aquatic biologists would advocate. Acknowledgments I am grateful to C. I. Weber, B. McFar- land, W. B. Horning, and G. 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Effects of post- glacial lakes on Fox Lake, Beaver Island, Michi- gan, based on analysis of the fossil diatom flora. Michigan Acad. 4: 349-358. Rosen, G 1981. Phytoplankton indicators and their rela- tions to certain chemical and physical factors. Lim- nologica 13: 263-290. Ross, R 1952, Diatoms from Neasham late-glacial de- posits. New Phytol. 51: 378-381. Round, F E. 1960. The epipelic algal flora of some Finnish lakes. Arch. Hydrobiol. .57: 161-178. Round. F E 1961. The diatoms of a core from Esthwaite Water. New Ph\ tol. 60: 43-59. 1964. The diatom sequence in lake deposits: some problems of interpretation. Verb. Int. Ver. Lim- nol. 15: 1012-1020. 1965. The application of diatom ecology to water pollution and purification. Pages 29-33 in C. M. October 1987 VanLandingham; Lake Tahoe 581 Tarzwell, ed.. Biological problems in water pollu- tion, 3rd Seminar. 1962. U.S. Dept. Health, Educ., Weir, Pub. Health Serv. Publ. 999- VVP- 25. Round, F E , .-iiND A J. Brook, 1959. The phytoplankton of .some Irish loughs and an assessment of their trophic status. Proc. Rov. Irish Acad., Sec. B. 60(4): 167-191. SCHELSKE, C L, 1984. In situ and natural phytoplankton assemblage bioassays. Pages 15-47 in L. E. Shu- bert, ed.. Algae as ecological indicators. Academic Press, London. SCHNITZLER. H 1971. Okologische Untersuchungen am Plankton der Riveristalsperre. Arch. Hydrobiol. 69: 60-94. SCHOEMAN. F R 1973. A systematical and ecological study of the diatom flora of Lesotho with special reference to the water quality. V & R Printers, Pretoria. 360 pp. 1979. Diatoms as indicators of water quality in the Upper Hennops River (Transvaal, South Africa). J. Limnol. Soc. S. Afr. 5: 73-78. Schroder, H 1939. Die Algenflora der Mulde; ein Bei- trag zur Biologic saprober Fliisse. Pflanzenfor- schung 21: 1-87. Shirshov, P P 1933. Sravnitel'nyi ocherk tsenozov re- ofil'nikh Vodoroslei r. Tulomy i nekotorykh drugikh vodoemov. Acta Inst. Bot. Acad. Sci. USSR, ser. 2, Plant. Crypt. 1: 65-91. Sladecek, V 1967. The ecological and physiological trends in the saprobiologv. Hvdrobiologv 30: 513-526. 1969. The measures of saprobitv. Verb. Int. Ver. Limnol. 17: 546-559. 1973. System of water (juality from the biological point of view. Arch. Hvdrobiol., Beih. Ergebn. Limnol. 7: 1-218. Smedman, G. 1969. An investigation of the diatoms from fourTertiarv lake bed deposits in western Nevada. PaleoBios9': 1-16. Smol, J P , S R Brown, and R N McNeelv 1983. Cul- tural disturbances and trophic history of a small meromictic lake from central Canada. Hvdrobi- ologia 103: 125-130. Sparlinc, J H , andC Nalew.-kjko 1970. Chemical com- position and phytoplankton of lakes in southern Ontario. J. Fish.' Res. Bd. Canada 27: 1405-1428. Sreenivasa, MR, and H C Duthie 1973. The post- glacial diatom history of Sunfish Lake, southwest- ern Ontario. Canadian]. Bot. 51: 1599-1609. Stadelmann. P 1971. Stickstofil F > H Fig. 3. Cluster dendrogram of plant species occurring in the study area grouped on the basis of niche overlap. Niche overlap values were based on frequency data relative to a species geographical distribution. important species was Distichilis spicata, fol- lowed by Muhlenbergia asperifolia, Cynodon dactylon, and juncus balticus. The distribu- tion patterns oi Distichilis spicata and Cyno- don dactylon are of interest. Away from the influence of the thermal water, these species often grew intermingled. However, near the water, C. dactylon formed a monospecific zone that was replaced by D. spicata just cen- timeters away from the hot water. The natural distribution of D. spicata ranges into areas of the western U.S. where climatic conditions tend to be cold over much of the year. In contrast, the natural distribution of C. dacty- lon ranges across much of the southern U.S. where the climate is mostly hot and humid and where frosts are rare. Since C. dactylon is adapted to such environments, its response to the elevated heat levels of the spring water and its competitive edge under such conditions near the spring are understand- able. Starting at the open water of the spring and moving toward the desert, a distance of some 100 m, a distinct moisture gradient is appar- ent. The major species in the vegetation sort well along this gradient. The dominant spe- cies of this zonation pattern are shown in Fig- ure 4. In the open-water areas, lily pads and algal mats dominate. The zones at the water's edge are generally single-species dominated and include Scirpus americanus and Eleocharis palustris. Through the middle portion of this moisture gradient, several spe- cies are important. In the outer and drier part of the gradient, the zones are again dominated by one or two taxa, with D. spicata increasing in importance away from the springs. October 1987 Brotherson. Rushforth: California Plant Communities 589 Table 3. Average percent cover values of plant species associated with major vegetation zones surrounding Benton Hot Springs. Zonation starts at the open water of the spring (I) and progresses outward to the saltgrass meadow (V) next to the desert. Vegetation zone Species III IV Scirpus americanus Eleocharis palustris Muhlenbergia asperifolia Juncus balticus Scirpus pungens Eleocharis rostellata Haplopappus acradenius Pohjpogon monspeliensis Poa navadensis Cynodon dactylon Distichlis spicata Eleocharis acicidaris Epilobium adenocaulon Chrysothamnus nauseosus Bromus tectorum Carex prae gracilis Rosa woodsii Halogeton glomeratiis Brotnus rubens Sporobolus airoides Erodium cicutarium Vulpia octiflora Conyza canadensis Artemisia ludoviciana Salix exigua 97.5 3.5 88.0 14.8 17.0 28.3 0.6 12.5 0.5 30.0 4.4 3.0 1.1 3.0 2.0 0.3 1.6 0.5 7.8 0.5 0.1 55.2 6.1 15.7 61.0 73.4 1.8 0.2 0.3 4.2 6.8 0.3 0.1 6.9 1.5 0.2 1.1 0.1 1.5 0.9 0.1 0.1 0.1 Literature Cited BOLEN, E G 1964. Plant ecology of spring-fed salt marshes in western Utah. Ecol. Monographs 34: 143-166. BouYOUCOS. G J. 1951. A recalibration of the hydrometer method for making mechanical analysis of soils. J. Agron. 43; 434-438. Brotherson, J D , andW E Evenson 1982. Vegetation communities surrounding Utah Lake and its bays. Report for the Utah Division of Wildlife Resources and the Bureau of Reclamation, Provo, Utah. 401 pp. Cole. L C 1949. The measurement of interspecific asso- ciation. Ecology 30; 411-424. COLWELL, R K . AND E J FuTUYMA 1971. On the mea- surement of niche breadth and niche overlap. Ecology 52; 567-576. Cronquist, a., a. H Holmgren, N H Holmgren, J L Reveal, and P K, Holmgren. 1977. Intermoun- tain flora — vascular plants of the Intermountain West, USA. Vol. 6. Columbia University Press, New York, New York. 584 pp. Daubenmire, R 1959. A canopy coverage method of veg- etational analysis. Northwest Sci. 33; 43-66. Hesse, P R. 1971. Textbook of soil chemical analysis. Wm. Clowes and Sons, Ltd., London. 520pp. Isaac, R A., and J D Kerber. 1971. Atomic absorption and flame photometry techniques and uses in soil, plant, and water analysis. Pages 17-38 in L. M. Walsh, ed.. Instrumental methods for analysis of soils and plant tissue. Soil Sci. Soc. Amer. Proc. 33. Jackson, M. L 1958. Soil chemical analysis. Prentice- Hall, Inc., Englewood Cliffs, New- Jersey. Jones, J B. 1973. Soil testing in the United States. Comm. Soil Sci. Plant Anal. 8; 307-322. Lindsay, W. L, .\nd W A. Norvell. 1969. Equilibrium relationships of Zn^*, Fe^*, Ca^*, and H* with EDTA and ETPA in soil. Soil Sci. Amer. Proc. 33: 62-68. Loam, J 1980. Hot springs and pools of the Northwest. Capra Press, Santa Barbara, California. 159 pp. MacArthl'r, R. H., and E O Wilson 1967. The theory of island biogeography. Princeton University Press, Princeton, New Jersey. 199 pp. MuNZ, P A 1968. A California flora. University of Califor- nia Press, Los Angeles. 1,681pp. Olsen, S R , V C. Cole, F S. W.\tanabe, and L A. Dean. 1954. Estimation of available phosphorus in soils by extraction with sodium bicarbonate. U.S. Dept. Agric. Circ. 939. Ostler, W K , K T Harper, M W Carter, and K B. McKnight 1981, Evaluating plant community 590 Great Basin Naturalist Vol. 47, No. 4 Table 4. Cole's Index values expressing positive and/or negative interspecific association between species found adjacent to Benton Hot Springs. Species Species x- Ct" SD,' Artemisia ludoviciana Bromus rubens Bromus tectorum Carex praegracilis Chrysothamnus nauseosus Conijza canadensis Cynodon dactylon Distichlis spicata Eleocharis pahistris Eleocharis rostellata Erodium cicutarium Halogeton glomeratus Polypogon monspeliensis Brojnus tectorum 24.99 1.00 0.20 Conyza canadensis 51.00 1.00 0.14 Salix exigua 24.99 1.00 0.20 Erodium cicutarium 24.46 0.48 0.09 Muhlenbergia asperifolia 3.86 -1.00 0.51 Sporoholus aeroides 11.98 0.24 0.07 Vulpia octo flora 24.46 0.48 0.09 Conyza canadensis 25.00 0.49 0.09 Eleocharis acicidaris 11.73 0.48 0.14 Salix exigua 11.73 0.48 0.14 Halogeaton glomeratus 9.83 0.70 0.22 J uncus halticus 7.96 1.00 0.35 Rosa woodsii 11.99 0.24 0.07 Eleocharis pahistris 3.83 -1.00 0.51 Salix exigua 6.76 0,13 0.05 Salix exigua 25.00 1.00 0.20 Eleocharis acicularis 4.55 0.09 0.04 Muhlenbergia asperifolia 10.94 0.65 0.19 Poa navadensis 11.13 0.28 0,08 Eleocharis pahistris 6.62 -0.45 0.17 Halogeton glomeratus 4.33 -0.39 0.19 Juncus halticus 6.69 0.16 0.06 Scirpus americanus 14.65 -1.00 0.26 Scirpus pungens 4.93 -0.66 0.30 Eleocharis rostellata 4.18 0.08 0.04 Epilobium adenocaulon 4.18 0.08 0.04 Halogeton glomeratus 4.28 0.27 0.13 Muhlenbergia asperifolia 13.99 1.00 0.27 Scirpus pungens 8.45 0.24 0.08 Halogeton glomeratus 4.76 1.00 0.46 Poa navadensis 6.41 1.00 0.39 Polypogon monspeliensis 24.99 1.00 0.20 Scirpus pungens 11.99 1.00 0.29 Vulpia octo flora 11.73 0.48 0.14 Muhlenbergia asperifolia 4.14 0.58 0.29 Rosa woodsii 4.76 0.09 0.04 Muhlenbergia asperifolia 9.13 0.18 0.06 Scirpus americanus 4.93 -1.00 0.45 Scirpus pungens 5.12 0.46 0,20 a = Chi-square; b - Cole s Index; c standard deviation of Cole s Index. monitoring designs used in the Uinta ecology pro- ject. Pages 222-255 in K. T, Harper, ed., Poten- tial ecological impacts of snowpack augmentation in the Uinta Mountains, Utah, Final Report to the Water and Power Resources Service, Department of Interior, Office of Atmospheric Water Re- sources Management, Denver. Ott. L. 1977. An introduction to statistical methods and data analysis. Duxbury Press, North Scituate, Massachusetts. 773 pp. Ranwell, D S 1973. Ecology of salt marshes and sand dunes. Chapman and Hall, London. 258 pp. Russell, D A. 1948. A laboratory manual for soil fertility students. 3d ed. Wm. Brown Co., Dubuque, Iowa, 56 pp. SCHAFFER. W. M., AND M. D Gadgil 1975. Selection for optimal life histories in plants. Pages 142-157 in M. Cody and J. Diamond, eds.. Ecology and evo- lution of communities. Harvard University Press, Cambridge, Massachusetts. Shupe, J B , J D Brotherson, and S R. Rushforth. 1986. Patterns of vegetation surrounding springs in Goshen Bay, Utah Countv, Utah, USA. Hydro- biologia 139: 97-107. Skougard, M G . AND J. D Brotherson 1979, Vegeta- tional response to three environmental gradients in the salt plava near Goshen, Utah County, Utah. Great Basin Nat. 39: 44-58. Sneath.R. H. A . andR R. Sokal 1973. Numerical taxon- omy: principles and practice of numerical classification. W. H. Freeman Co., San Francisco. 573 pp. Warner. J. H , and K. T Harper 1972. Understory char- acteristics related to site quality for aspen in Lftah. Brigham Young Univ. Sci. Bull., Biol. Series 16(2): 1-20. October 1987 Brotherson, Rushforth: California Plant Communities 591 Dry Wet Desert Distichlis striata Distichlis stricta—Chrysothamnus nauseosus Distichlis stricta—Juncus balticus Mixed species meadow Eleocharis palustris Scirpus americanus Lilly pad / Algal mat \ Zonation scheme J Fig. 4. Schematic diagram of vegetation patterns in the meadows surrounding the hot and warm springs complex at Benton, Mono County, Cahfornia. Listed are the major dominants of each zone in relation to their placement along a moisture gradient beginning at the spring and ending in the desert. Table 5. Prevalent species associated with the vegeta- tion surrounding Benton Hot Springs along with their importance values; the P x C index is based on percent presence of a species in the different zones multiplied by its mean cover across all zones. Species p X C Index 38.0 8.8 5.9 4.4 3.2 L2 0.7 Distichlis spicata Muhlenbergia asperifolia Cynodon dactijlon J uncus balticus Eleocharis palustris Scirpus americanus Chrijsothamnus nauseosus NEW BRACHIOSAUR MATERIAL FROM THE LATE JURASSIC OF UTAH AND COLORADO James A. Jensen' Abstract — Little is known about the Brachiosauridae, which includes some of the largest known sauropods, such as the genus Brachiosaurus, discovered in western Colorado by Elmer S. Riggs in 1900. Additional diagnostic material, previously unknown in the western hemisphere, is reported from three comparatively recent quarries: the Jensen/ Jensen Quarry in eastern Utah and the Dry Mesa and Potter Creek quarries on the Uncompahgre Upwarp in western Colorado. An unknown, well-preserved, articulated sauropod atlas/axis, seven cervical vertebrae, and an interesting flora were associated with the Potter Creek Quarry brachiosaur material. Taphonomic factors in that quarry are noted. The Jensen/Jensen and Dry Mesa deposits occur in basal sediments of the Brushy Basin Member of the Morrison Formation, and the Potter Creek Quarry in an intermediate section of that member. No complete, articulated skeleton of the sauropod genus Brachiosaurus has been re- ported from North America. However, an in- complete skeleton was collected in Colorado in 1901, and disarticulated bones of the genus have been found in at least four other locali- ties. Elements described here, not previously reported from the western hemisphere, in- clude a partial scapula, a distal cervical verte- bra, a radius, a metacarpal, and a humerus. The radius, metacarpal, and humerus appear to represent a novel species but will not be described here as such. In 1900 the type-species of the genus Bra- chiosaurus was collected by Elmer S. Riggs, of the Field Columbian Museum, Chicago, who discovered a partial skeleton of this re- markable sauropod near Grand Junction, Col- orado. This skeleton possessed the previously unknown feature of front legs equal in length to the rear (Fig. 1), which elevated the base of the neck and thorax far above any spinal incli- nation previously reported in sauropods. Riggs (1903) appropriately named it Bra- chiosaurus altithorax. He recovered approxi- mately 20 bones, including seven articulated presacral and two caudal vertebrae, a sacrum and the right ilium, a left coracoid, right humerus, right femur (Fig. 1), and four ribs. The femur and humerus were greatly com- pressed, with the distal end of the latter being partially destroyed by surface erosion (Fig. 1). This material is now preserved in the Field Museum of Natural History, Chicago. A decade later a second discovery of bra- chiosaur bones was collected by a German paleontologist, Janensch, in Tendaguru, Tan- zania, formerly East Africa. He recovered a fairly complete skeleton that he named B. brancai (Janensch 1914); the restored skele- ton is now mounted in the Museum fiir Naturkunde in East Berlin, East Germany. Subsequent work by British expeditions, and possibly other European institutions, recov- ered other brachiosaur materials from Tanza- nia, but for more than 80 years no additional brachiosaur remains were scientifically re- ported from the western hemisphere. Circa 1943 a brachiosaur skeleton in an ad- vanced state of erosion was discovered on the Uncompahgre Upwarp in western Colorado by the late Daniel E. Jones and his wife, Vi- vian, of Delta, Colorado. The humerus (Figs. 2B, 3A-D, 4B) was collected and donated to the U.S. National Museum in Washington, D.C., but was never described. The discov- ery site, approximately 70 km SSE of the Riggs locality, was named the Potter Creek Quarry. Its stratigraphic position is approxi- mately in the middle of the Brushy Basin Member of the Morrison Formation. I worked there two seasons (1971, 1975), col- lecting five disarticulated elements of a large sauropod (? B. altithorax), bones of a second, smaller sauropod genus, and teeth of an un- known theropod. The brachiosaur elements collected include part of the discovery humerus (Figs. 3E, 5A-D, 6B), a medial '2821 North 700 East, Provo, Utah 84604. 592 JENSEN; New Dinosaur Material Bi C 593 Fig. 1. A-D, F-H, elements of the type o( Brachiosaurns altithorax (from Riggs 1904): A, humerus, anterior view; Ai, proximal end; B, femur, anterior view; Bi, proximal end view; C, right ilium; D, fifth presacral vertebra; E, Potter Creek Quarry brachiosaur, fourth or fifth presacral vertebra; F, thoracic rib head, anterior view; G, B. altithorax, thoracic rib head, mesio-anterior view; H, B. altithorax. lateral view of left coracoid. Scale: A-D, F-H, approximately 1/12 natural size. dorsal vertebra (Figs. 3D, 4A-A3), an incom- plete left ilium (Fig. SA-A^), and a left radius and metacarpal (Figs. 3B, 5E-Ei). Materials of the smaller, indeterminate sauropod in- clude the broken fragments of an articulated vertebral series from the atlas/axis to the sev- enth cervical vertebra. This series was found intact but excavated in fragments by the Jones family and given to me. I was able to reassem- ble an articulated atlas/axis and third cervical 594 Great Basin Naturalist Vol. 47, No. 4 i^ i^»fe iiT * Mm Fig. 2. A, Jensen/Jensen Quarry: scapula with coracoid in foreground (the only existing illustration of these unprepared brachiosaur elements); worker in upper right corner is sawing around border of 9' brachiosaur rib; B, Potter Creek Quarry. vertebra (Fig. lOA-E) from this broken mate- rial because of its excellent preservation. A detailed study of some of this material is in progress, but a preliminary examination re- veals it to be from a mature sauropod. The elements noted here are much too short and small for any described brachiosaurid. In 1960 I discovered a dinosaur bone de- posit in basal Brushy Basin Member sedi- ments of the Morrison Formation near October 1987 JENSEN: New Dinosaur Material 595 Fig. 3. Potter Creek Quarry brachiosaur: A-A2, left ilium (dorsal border, ischiadic peduncle restored); B, radius; C, metacarpal; D, fourth or fifth dorsal vertebra; E, left humerus. Abbreviations: dc, deltoid crest; ms, muscle fossa. Jensen, Utah. This deposit (the Jensen/Jensen Quarry) is located south of the Green River, a few miles from the Dinosaur National Monu- ment Quarry. Two years' work (1962, 1966) in this quarry (Figs. 11, 13) produced several brachiosaur elements including a rib 2. 75 m (9 ft) long (Fig. 6B), a distal cervical vertebra, the proximal half of a scapula, and a coracoid. Many worthless slivers and fragments of shat- tered brachiosaur cervical vertebrae were en- countered. Because the coracoid associated with the scapula does not appear to match the coracoid of B. altithorax, the specific identity of the elements is presently in question. When fully prepared, the material may repre- sent an undescribed species; but an in- sufficient number of elements duplicating those of the type-species presently precludes such a determination. Additional, well- preserved brachiosaur material, cited in the Uncompahgre fauna (Jensen 1985), is de- scribed here from the Potter Creek Quarry. 596 Great Basin Naturalist Vol. 47, No. 4 Fig. 4. Dorsal vertebrae: A-A3, Potter Creek Quarry brachiosaur, fourth or fifth dorsal vertebra, right lateral view; B-B2, Dystijlosaurus edivini, type (B), anterior (B,), posterior (B,), right lateral views, probably anterior dorsal; C, Ultrasaurus macintoshi, type posterior dorsal vertebra, 1.45 m tall, lett lateral view. October 1987 JENSEN; New Dinosaur Material 597 Fig. 5. Potter Creek Quarry: A-D, brachiosaur humerus. A, proximal end; B, mid-shaft section; C, detail of bulbous deltoid crest; D, anterior, distal end; E, metacarpal MC I, mesial view; Ej, same, lateral view. Abbreviations: dr, deltoid ridge; ms, muscle fossa/scar. 598 Great Basin Naturalist Vol. 47, No. 4 Fig. 6. A, Scapulocoracoid referred to Ultra.saunis nuicintoshi. prone figure 6'.3" tall; B, Jensen/Jensen Quarry brachiosaur rib, Dry Mesa Quarry Ultrasaunts scapulocoracoid. Potter Creek Quarry brachiosaur left humerus. All three elements cast in fiberglass resin. October 1987 JENSEN: New Dinosaur Material 599 y?fiL:^dl^ J I m Fig. 7A-B. Reconstructed front limb with cast scapulocoracoid of Ultrasaurus macintoshi (figure 6'3" tall): A, mid-cervical vertebra, Supersaurus vivianae, anterior view (original seen in Fig. 8); B, same, left lateral view. Vertebra restored from original and cast in fiberglass resin. This material is much better preserved than that of the type of B. altithorax (Riggs 1903) and justifies some revision of the generic diag- nosis (see Systematic Paleontology). In 1972 I opened a quarry near Dry Mesa (Dry Mesa Quarry) in basal Brushy Basin 600 Great Basin Naturalist Vol. 47, No. 4 poc Fig. 8. A, Proximal end of brachiosaur femur, proximal end 5'6" in circumference, from Recapture Member of the Morrison Formation; B, Siipersatirus vivianae, right lateral view of mid-cervical vertebra; C, mid-cervical vertebra, Supersaurus vivianae right lateral view (restoration seen in Fig. 7). Abbreviations: acx, anterior convexity; bns, bifurcate neural spine; idl, infradiagonal lamina; poc, posterior concavity; pp, parapophysis; prdl, prediapophysial lamina; prz, prezygapophysis; pz, postzygapophysis; sdl, supradiagonal lamina; tp, transverse process; vl, ventral lamina. Member sediments on the NE monocline of the Uncompahgre Upwarp in western Colo- rado. This quarry (Fig. 13) lies approximately 20 km NW of the Potter Creek Quarry but is on a significantly lower horizon. A decade of work in it produced many tons of dinosaur- related materials including bones of several unusually large sauropods (Jensen 1985), some of which appear to be brachiosaurid. Among the large elements recovered was a (?) mid-cervical vertebra more than 1 m in length (Figs. 7A-B, 8C), which, having a bifurcate October 1987 JENSEN: New Dinosaur Material 601 Fig. 9, Scapula (coracoid) profiles of eight sauropod genera: A, Haplocanthosaunis; B, Supersaurus vivianae; C, Cetiosaunis; D, Diplodocus; E. Cainarasaurus; F, Apatosaurus; G, Supersaurus; H, Brachiosaurus; I, Ultrasaurus. Not to scale. 602 Great Basin Naturalist Vol. 47, No. 4 /4 * pp ax Fig. 10. Potter Creek Quarry, unidentified sauropod atlas/axis with intercentrum third cervical vertebra: A, superior view; B, inferior view; C, anterior view; D, right lateral view; E, posterior view. Abbreviations: at, atlas; ax, axis; erf, cervical rib fragment; ctp, collapsed transverse process; dp, diapophysis; ira, incorrectly restored area (x x in dotted lines); n, neurapophysis; pp, parapophysis. spine, was readily identifiable as unrelated to Brachiosaurus. Because of its huge size, how- ever, an error was made in referring it to Ultrasaurus macintoshi Jensen (1985), in the Brachiosauridae. To mitigate this error, I here remove the vertebra, BYU 5003, from Bra- chiosauridae and provisionally refer it to the Diplodocidae. This referral is based on two factors: principally, a bifurcate neural spine. and, secondly, the fact that two unusually large scapulocoracoids (Figs. 9B, 9G), found in the same (Dry Mesa) quarry, were refer- able to the Diplodocidae. One of these (BYU 5500, Fig. 9B) is the holotype of Supersaurus vivianae Jensen (1985). A large rib (Figs. IF, 8B), though broken into many sections, ap- pears to have been more than 3 m (over 10 ft) long. October 1987 JENSEN: New Dinosaur Material 603 Fig. 11. Jensen/Jensen Quarry, 1966: A, Dinosaur National Monument Quarry; B, same quarry in 1986. In 1979 a scapulocoracoid, 2.70 m (8' 10") readily referable to the Brachiosauridae (Fig. long (Figs. 6A-B, 91) was collected in the Dry 9H) and is the holotype of Ultrasaurus macin- Mesa Quarry. This scapula, BYU 5000, is toshi Jensen, 1985. 604 Great Basin Naturalist Vol. 47, No. 4 Fig. 12. Profiles of various sauropod femora: A, brachiosaurid. Recapture Creek Member, Morrison Formation; B, apatosaur; C, Diplodocus; D, unidentified. Dry Mesa Quarry. Abberviations: alam, alamosaur; amph, amphicoelias; apato, apatosaur; brach, brachiosaur; camar, camarasaur; diplo, Diplodocus; haplo, haplocanthosaur. All scale bars equal 0.5 m. In 1985 I found the proximal third of an extremely large sauropod femur (Figs. 8A, 12A) in a uranium miner's front yard in south- ern Utah. The head of this femur is 1.67 m (5 '6") in circumference and was collected from the Recapture Creek Member of the Mor- rison Formation in Utah near the Arizona bor- der. It is the largest bone I have ever seen; it is also the first dinosaur bone reported from the Recapture Member of the Morrison Forma- tion and is herein pictured in Figure 8A. The proximal end of a sauropod femur is generally October 1987 JENSEN: New Dinosaur Material 605 >A R / Z V N A Fig. 13. Map of 26 quarries worked by the author in the Cretaceous and Jurassic of Utah and Colorado during a 20-year period. Name ofquarry and year(s) worked, Hsted chronologically; 1, Jensen/Jensen, 1962, 1966; 2, Red Seeps, Easter, 1966; 3, North Horn, 1966; 4, Recapture, 1967, 1982; 5, Dominguez/Jones, 1967; 6, Cactus Park, 1968, 1977; 7, Singleton Flat, 1969; 8, Gilmore Gulley, 1969, 1980; 9, Kelvin, 1970; 10, Uravan, 1970; 11, East Fork Hadrosaur, 1971; 12, Potter Creek, 1971, 1975; 13, Gilmore Lizard, 1971; 14, Dr\- Mesa, 1972-1983; 15, Pterosaur Tracks, 1973; 16, Picnic Springs, 1973; 17, Navajo Hill, 1973; 18, Hinkle, 1973; 19, Dalton Well, 1975, 1978; 20, Calico Gulch, 1973, 1976; 21, Cedaredge Mosasaur, 1979; 22, Titanosaur, 1980; 23, Hummingbird, 1981; 24, Holly Hollow, 1982; 25, Faithful Smith, 1982; 26, Rotten Fuse, 1982. 606 Great Basin Naturalist Vol. 47, No. 4 not significantly diagnostic, but in profile (Fig. 12A) this specimen resembles the Upper Cretaceous Alamosauriis (Fig. 12 alam.) more than it does profiles of Jurassic sauropods (Fig. 12). In the latter group it bears the greatest resemblance to the profile of Brachiosaurus (Fig. 12 brach.) and is here referred to that family. Systematic Paleontology Suborder Sauropodomorpha Infraorder Sauropoda Brachiosauridae Brachiosaurus Riggs 1903 Revised generic diagnosis. — Humerus and femur of subequal length; humerus with deltoid crest located one-third of total shaft length down from proximal end; neural arches moderately elevated, all neural spines single, not bifid, increasing in height anteriorly from sacrum to mid-dorsal region, short transverse processes on first presacral vertebra increas- ing in length on each vertebra to the mid-dor- sal section, dorsal centra with well-developed pleurocoels, hyposphene-hypantrum articu- lation well developed; height of first two pre- sacral vertebrae shorter than the preceding series, with length of centra short, length of the third to seventh presacral centra equal to half the vertebra's total height, measured from ventral border of anterior convexity to spinal apex; dorsal rib heads pneumatic; sacrum with five ilium-supporting vertebrae, width of sacrum approximately equal to length, with short sacral spines and five co- ossified centra; anterior caudal vertebrae with short neural spines, moderately developed caudal ribs, and no pleurocoels. Referred specimens. — BYU 9754: mid- dorsal vertebra, partial left ilium, left radius, one right metacarpal, left humerus, and vari- ous rib sections, all associated. Species Indeterminate Horizon and locality. — An intermediate horizon of the Brushy Basin Member, Mor- rison Formation, Late Jurassic Period; Potter Creek Quarry, T49N, R12W, SW 1/4, Sec 5, Montrose County, Colorado. Collector. — J. A. Jensen. Description. — Mid-dorsal vertebra. The height of the vertebra is comparatively greater than that of the type with a proportion of centrum length to total vertebral height of 3 to 7, compared to a proportion of 3.7 to 7.2 in the type (Riggs 1904). The supraprezygopo- physeal laminae are not parallel, as in B. al- tithorax, but conjoined midway up the neural spine, forming a robust pre spinal lamina that transversely increases in width dorsally (Figs. 3D, 4Ai). Both diapophyses are missing, leav- ing the length of the transverse processes un- known. A moderately developed hyposphen- hypantrum articulation contrasts with the unusually developed intervertebral articula- tions in B. altithorax. An elongate centrum has well-developed pleurocoels. The apex of the neural spine is expanded into a robust 90-degree, transverse, gablelike metapophy- seal cap (Fig. 4Ai). The neural arch is con- stricted around its base (Fig. 4A-Ai) rather than being anteroposteriorly long as in Ultra- sauriis Jensen, 1985 (Fig. 4C), or long and broad as in Dystylosaurus Jensen, 1985 (Fig. 4B-Bo). The inner and outer distal condyles of the humerus are anteriorly prominent (Fig. 5D). The rugose crest of the deltoid ridge is bul- bous, comparatively short (Fig. 5B-C), and centered one-third of the total shaft length below the proximal end. A prominent, deep muscle fossa with a transverse, crenulated, lower margin (Fig. 5A) occurs in the upper part of the broad, anterior valley, adjacent to the deltoid ridge. A metacarpal (Fig. 5E-Ei), probably right, MC III, has a laterally expanded distal end. The radius (Fig. 3B), with few distinguish- ing features, is tentatively identified as the left. The anterior iliac process is massive and shorter than that of B. altithorax. The dorso- posterior third of the ilium, including the is- chiadic peduncle, is missing and is conserva- tively restored here after several Tendaguru brachiosaur ilia in the British Museum (Natu- ral History) (Mcintosh 1980, personal com- munication). The pubic peduncle is long and thin, viewed laterally, forming a weak ante- rior acetabular arch. Discussion. — A deep muscle fossa with a crenulated lower margin (Fig. 5A ms) occurs on the humerus in the upper part of a broad valley adjacent to the deltoid ridge, marking the terminal insertion of a large adductor October 1987 JENSEN: New Dinosaur Material 607 cle. This may have been the "antero-superior muscle" identified in Camarasaurus supre- 7nus by Osborn and Mook (1921), or the M. pectorahs, or an equivalent of the M. del- toideus, said to terminate on or near the del- toid ridge in ornithischian dinosaurs (Romer 1927). This fossa is not known to be equally prominent in other sauropod genera. The long, comparatively weak pubic pe- duncle of the ilium suggests the anterior end of the ilia may have been rotated ventrally around a transverse acetabular axis, similar to the 20-degree iliac rotation seen in the sauropod Cathetosaiirus leivisi Jensen (in press). In that genus a ventral rotation of the anterior iliac processes placed a stronger, well-buttressed section of the ilia above the head of the femur. This rotation, not reported in other sauropod genera, allowed C. lewisi to elevate the anterior body, neck, front limbs, and thorax to a bipedal stance. A similar iliac rotation in brachiosaurs would have compen- sated for an elevated thorax due to their un- usually long front limbs (Riggs 1903). In non- bipedal sauropods, such as the Apatosauridae, Diplodocidae, and Camarasauridae, elevation of the anterior body would have obliged the weakest cross section of the pubic peduncle to carry a major amount of body weight. Unidentified sauropod. It is concluded here that the atlas/axis and articulated third cervical vertebrae (Fig. 10) belong to an unidentified sauropod. This determination is strengthened by the allochthonous nature of the deposit in which three families were rep- resented; however, only mild evidence of strong, fluctuating currents, such as heavy cross-bedded sands, grits, bone abrasion, and rip-up mudclasts, was encountered during ex- tensive excavations in the area. An autochthonous deposit of dinosaur bones usually contains the remains of one skeleton, representing the one-time death- site burial of an individual (Dodson et al. 1980), characteristically isolated from the dis- ruptive hydraulic forces of active channel en- vironments. Allochthonous deposits, on the other hand, are composed of disarticulated parts of various vertebrates collected by active hydraulic forces sweeping a drainage area during an indefinite, extended period of time. Correcting an earlier, inaccurate report on the Potter Creek fauna (Dodson et al. 1980), which listed one taxon and the pattern of bone occurrence as "isolated skeletal parts, " the Potter Creek faunal list includes at least three families: two sauropodomorphs; Brachiosati- rus sp., and an unidentified smaller sauropod; and an unusually large theropod, possibly Torvosaunis Galton and Jensen (1979), or a large allosaurid. Furthermore, the pattern of bone occurrence is associated and articu- lated, rather than "isolated," as reported, and the locality produced elements of a well- preserved flora consisting of various unde- scribed reproductive structures. Taphonomy. — The huge brachiosaur ilium was partially destroyed, broken diagonally through its thickest section and separated from the dorsoposterior section, which was never found. This damage was not the result of levee overwash, stream abrasion, large- animal turbation, postburial pressure and faulting, nor scavengers, since no teeth marks were found in any of the bones. Also, the uncrushed, articulated, unidentified, smaller- sauropod cervical series was found adjacent to the broken ilium, undamaged by the force(s) partially destroying that huge element. The ilium was apparently broken elsewhere, the parts separated, with only one being trans- ported to the site. Unusually strong hydraulic pressure would have been required to move such a heavy, irregular shape, but no evi- dence of high-energy fluvial activity was present in the surrounding sediments and so no explanation of this enigma is readily apparent. When I first visited the locality, a consider- able amount of shattered dinosaur bone, obvi- ously belonging to a large individual, was ly- ing on the slope below the deposit. The Jones family informed me that more was present when they discovered the site many years earlier. This lead to the conclusion that the major portion of a brachiosaur skeleton was present before erosion. Flora. — Considerable fossil plant material was present in an area adjacent to the quarry horizon in the form of reproductive struc- tures. Cycadophyta seeds were common, from the family Cycadales (Chandler 1966), on fragments of macrosporophyll, including the micropyle of fertile embryos. I collected approximately one liter of these organs, as well as immature seeds of Behuninia joannei (Chandler 1966) and mature seeds of the Cycadophyta Jensensispermum redmondi 608 Great Basin Naturalist Vol. 47, No. 4 (Chandler 1966). Other reproductive struc- tures included a cone of the gymnosperm Coniferales, family Taxodineae, Sequoia sp., seeds of the genus Carpolithus Linnaeus in- certae sedis (Chandler 1966), and many megasporophyll fragments. This fossil plant material, a faunal list, and the information on taphonomy were available but not published in the first taphonomic report on the quarry (Dodson et al. 1980). Acknowledgments The Daniel E. "Eddie" Jones family of Delta, Colorado, were responsible, circa 1943, for the first new brachiosaur bones found in the western hemisphere since the discovery of the type species o(Brachiosaurus by E. S. Riggs in Colorado in 1900. Other brachiosaur bones described here, particu- larly those from the dry Mesa Quarry, are also the result of their extensive explorations on the Uncompahgre Upwarp in western Colo- rado. 1 thank Dr. John S. Mcintosh for his encouraging support. Dr. Samuel P. Wells and Dr. James R. Jensen for criticizing the manuscript, and Dr. Stephen L. Wood, edi- tor. Great Basin Naturalist, for his continuing support that has enabled me to continue pub- lication of the results of 23 years of collecting new dinosaurs. Literature Cited Chandler, M E J 1966. Fruiting organs from the Mor- rison Formation of Utah, USA. Bull. British Mu- seum (Natural History) Geology 12(4); 139-171. Dodson, PA K Behrensmeyer, R T Bakker, and] S McIntcsh 1980. Taphonomy and paleoecology of the dinosaur beds of the Jurassic Morrison Forma- tion. Paleobiology 6(2): 208-232. Galton, P M , AND J A Jensen 1979. A new large theropod from the upper Jurassic of Colorado. Brigham Young Univ. Geol. Stud. 26(2): 1-12. Janensch, W 1915. Die wirbelsaule von Brachiosatirus brancai. Palaeontographica Supplement 7 Erste Reihe 3. Jensen, J. A. 1985. Three new sauropod dinosaurs from the Upper Jurassic of Colorado, and the Uncom- pahgre fauna, a preliminary report. Great Basin Nat. 45(4): 697-720. Osborn, H F , AND C. C. MooK. 1921. Camarasaurus, Amphicoelias , and other sauropods of Cope. Mem. Amer. Mus. Nat. Hist. 3(3): 251-284. RiGGS, E S 1903. Brachiosatirus altithorax, the largest dinosaur known. Amer. J. Sci. 15(4): 299-366. 1904. Structure and relationships of opishtocoe- lian dinosaurs. Field Columbian Mus. Geology Ser. 94(2): 229-247. Romer, a. S. 1927. The pelvic musculature of ornithis- chian dinosaurs. Acta. Zoologica Bd. 8: 225-275. SMALL-STONE CONTENT OF MIMA MOUNDS OF THE COLUMBIA PLATEAU AND ROCKY MOUNTAIN REGIONS: IMPLICATIONS FOR MOUND ORIGIN George W. Cox', Christopher G. Gakalui", and Douglas W. Allen' Abstr.\ct — Mima moundfields were investigated at the Lawrence Memorial Grassland Preserve, located on the Columbia Plateau in southern Wasco County, Oregon, and at three locations in the San Luis Valley and Sangre de Cristo Mountains, southern Colorado, to test the alternative hypotheses of mound origin by erosion, frost action, and soil translocation by geomyid pocket gophers. The concentrations of two size classes of small stones, gravel (8-15 mm diameter) and pebbles (15-50 mm diameter), were sampled along mound-to-intermound transects and at different depths within the mounds. Numbers and masses of small stones per unit soil volume increased from intermounds to mound tops at the Colorado sites and from mound edge to mound top at the Oregon site, where thin intermound soils lay directly on the weathering surface of basalt bedrock. Numbers and masses of small stones in the surface soil of mound tops were greater than or similar to concentrations in deeper layers. Mean masses of individual pebbles were greater in the intermound zone than in mound soils at the Oregon site, but did not differ along mound-intermound gradients at the Colorado sites. Ratios of gravel to pebbles varied significantly along the mound-intermound gradient at the Oregon site and at one Colorado site, being highest at mound edges or in intermounds. These observations support the hypothesis that mounds are formed by centripetal translocation of soil by geomyid pocket gophers, and are contrary to predictions based on theories assuming erosion or frost action to be the mechanism of mound formation. In western North America, earth mounds, which reach about 25 m in diameter and 2 m in height and are commonly known as Mima mounds, occur in many locations from south- ern Canada to northern Mexico (Cox 1984a). The density of mounds ranges from about 1 to 3 per ha in localities in the Great Plains and to more than 50 per ha in many localities in California. The material forming these mounds consists largely of soil and small stones (up to about 50 mm in diameter) but includes few stones of larger size, although these may be abundant in intermound areas. Mounds of similar nature also have been re- ported in East Africa (Cox and Gakahu 1983, 1987), South Africa (Lovegrove and Siegfried 1986), and Argentina (Cox and Roig 1986). In the interior montane region of western North America, Mima mounds occur from southern British Columbia, Canada (O. Slay- maker, personal communication), to central Sonora, Mexico (Hill 1906). They are very widespread on the Columbia Plateau of east- ern Washington, north central Oregon, and southwestern Idaho (Freeman 1926, Fosberg 1965, Kaatz 1959, Malde 1961, 1964, Waters and Flagler 1929). In the Rocky Mountain region of the United States they occur in val- leys and basins and on plateaus and mountain meadows from eastern Idaho and southwest- ern Montana south through northeastern Utah and Wyoming (R. Reider, personal com- munication) to Colorado (Murray 1967, Vitek 1978) and northern New Mexico (J. D. Vitek, personal communication). Three major hypotheses have been sug- gested for the origin of mounds in the interior montane region of North America: (1) water erosion, (2) periglacial freeze-thaw dynamics, and (3) soil translocation by geomyid rodents. Waters and Flagler (1929) postulated that the mounds of the Columbia Plateau resulted from the erosion of a volcanic ash layer laid down over the surface of basaltic rock, the intermound zones constituting "erosion fur- rows." Fosberg (1965) suggested that the stone nets often associated with Columbia Plateau mounds were formed by frost-sorting processes, and that soil material deposited over this system was eroded to leave mounds within the stone polygons. The erosional hy- pothesis was also supported by Knechtel (1962) and Washburn (1980). Others have regarded the mounds, as well as the sorted stone nets often associated with them, to be a periglacial phenomenon. Kaatz 'Department of Biolog> , San Diego State University, San Diego, California 92182. ^Department of Wildlife Management, Moi University, Box .3900, Eldoret, Kenya. 609 610 Great Basin Naturalist Vol. 47, No. 4 (1959) suggested that moundfields were a thermokarst landscape, with the mounds rep- resenting the centers of former ice-wedge polygons. Malde (1961, 1964) and Brunn- schweiler (1962) concluded that the mounds were formed in the late Pleistocene by pro- cesses of freeze-thaw and solifluction. In the Sangre de Cristo Mountains of southern Colo- rado, Frederking (1973) interpreted the mechanism of formation of mounds in lower alpine tundra areas to be frost heave, soil creep, and solifluction. Finally, the Dalquest and SchefiPer (1942) hypothesis that Mima-type mounds form by the centripetal translocation of soil resulting from outward tunneling of pocket gophers from their centers of activity has been applied to mounds of this region (Larrison 1942, Price 1949, Cox 1983a). Cox and Gakahu (1986) derived alternative predictions of the major hypotheses of Mima mound origin. These predictions pertained to the small stone content of mound and inter- mound soils, and to moundfield geometry. They tested these predictions against data from four Mima moundfields in western Washington, central California, and southern California. They concluded that the results strongly supported the pocket gopher hypoth- esis of mound origin. Our studies extend this test to mounds of the Columbia Plateau of eastern Oregon and to mounds of valley floors, upland mesas, and alpine tundra in southern Colorado. Procedure Study Areas In Oregon we investigated moundfields on and adjacent to the Lawrence Memorial Grassland Preserve (hereafter, Lawrence Preserve), a Registered National Natural Landmark owned by the Nature Conser- vancy, near Shaniko, southern Wasco County (44°57'N, 120°48'W). The mounded portion of this preserve is typical "biscuit scabland" (Copeland 1980) and lies at an elevation of 1,036-1,060 m on the Shaniko Plateau, formed of Columbia River basalts. The nu- merous Mima mounds range up to about 1 m in height and about 20 m in diameter. The mound soils are classified as Condon aeolian silt loams and the shallow intermound soils as Bakeoven residual, very cobbly loams. The climate of this region is cold and semiarid, with annual precipitation averaging 280 mm. The vegetation of the mounds is dominated by Idaho fescue {Festuca idahoensis) and blue- bunch wheatgrass (Agropyron spicatum), and that of the intermounds by Sandberg blue- grass {Poa sondbergii), scabland sagebrush (Artemisia rigida), bitterroot (Lewisia re- diviva), and several species of biscuitroot {Lo- matium spp.). The northern pocket gopher (Thomomys tolpoides) is abundant at this site. This area was studied between 24 and 28 May 1986. In southern Colorado three sites, all origi- nally investigated by Vitek (1978), were stud- ied. These sites span a wide range of altitudi- nal and climatic conditions. Sampling of these sites was carried out between 30 July and 4 August 1986. The Blanca South site (37°20'N, 105°33'W) is located on the floor of the San Luis Valley, about 13 km south of the community of Blanca, Costilla County, at an elevation of 2,375 m. These mounds range from about 8.4 to 16.8 m in diameter and from 11.4 to 42.5 cm in height, and are developed on a residual sandy loam overlying extrusive basalt bedrock. The arid climate has less than 20 cm annual precipitation and is extremely cold in winter. The vegetation of the mounds is domi- nated by winterfat (Eurotia lanata) and blue grama (Boutelouo gracilis), with snakeweed (Giitierrezia sarothrae) and globemallow (Sphaeralcea coccinea) increasing in impor- tance in intermound areas. The valley pocket gopher (Thomomys bottae) is common at this location. The Mosca Flats site (37°46'N, 105°23'W) is located 9 km west of Red Wing, in western Huerfano County at an elevation of 2,800 m. Mounds at this location range from 8.2 to 13.0 m in diameter and from 20 to 71 cm in height. Soils are sandy loams developed on Quater- nary gravels overlying Tertiary volcanics. Mean annual precipitation is probably 20-36 cm, and the vegetation of both mound and intermound areas is dominated by blue grama and pasture sagebrush (Artemisia frigida). The northern pocket gopher (T. talpoides) is abundant at this site. The Alpine Ridge site (37°39'N, 105°29'W) lies at an elevation of 3,615 m in a saddle of the main ridge of the Sangre de Cristo Moun- tains on the border of Alamosa and Huerfano October 1987 Cox ETAL.: Mima Mounds 611 counties. Mounds range from 8.4 to 16.8 m in diameter and from 11.4 to 39.4 cm in height. Soils are residual sandy loams, in this case developed on Precambrian metamorphic rocks. Precipitation at this lower alpine tun- dra site is probably in excess of 50 cm. The vegetation of mounds and intermounds is dominated by Kobresia myosuroides, with plant cover in the intermounds being sparser and richer in mosses and lichens. The north- ern pocket gopher is abundant at this site. Hypotheses Based on the analysis of mound-formation hypotheses by Cox and Gakahu (1986), we postulated the following patterns for small rock content of mound and intermound soils: Erosion hypothesis. — The concentration of both gravel and pebbles will be greater for intermound and mound edge than for mound tops because some concentration of these ero- sion-resistant elements should occur as the fines are removed to reduce the intermound surface level. Because the smaller gravel frac- tion should be carried away more than the pebble fraction by such erosion, the gravel/ pebble ratio should be lower for the inter- mound and mound edge than for the mound top. Mean pebble mass should be least on the mound top and greatest at the mound edge and in the intermound zone. Frost-sorting hypothesis. — The concen- tration of gravel and pebbles should increase from mound centers to the center of the inter- mound zone because of transport of these stones to the margins of convectional cells (intermound centers). Because the larger pebbles should be moved more actively, the ratio of gravel to pebbles should be greatest on mound tops. The mean size of pebbles should also increase progressively from mound top to mound edge and intermound center. FOSSORIAL rodent HYPOTHESIS. — Both gravel and pebbles should be more concen- trated on mound tops than at mound edges, if soil and small stones are moved moundward by animal activity and if fines are selectively returned toward the intermounds by erosion. Concentrations should also be greater at mound edges than in intermound areas, un- less the intermound zone is a strong source area of weathering rock fragments. Gravel/ pebble ratios should not be greatest on mound tops, however, because erosion should also tend to return more gravel than pebbles to- ward the intermounds. Mean pebble masses should be greater in the intermound zone than in the mounds, but values for mound edge and mound top should be similar be- cause the major transportational bias should be exerted during movement of pebbles from intermound to mound edge. Methods Four (Alpine Ridge) to six (other sites) mounds were selected at each site for sam- pling small-stone content of mound and inter- mound soils. The diameters and maximum heights of these mounds were measured. These mounds were chosen because they were among the largest available and were surrounded on all sides by intermound flats. On the top of each mound, a 2-m square was marked out, with sampling locations desig- nated at each corner. From these corner points, transects were paced outward toward the centers of the four widest intermound zones and sampling locations designated at the mound edge (0.5 m inward from the edge proper) and at a point one mound radius be- yond the edge. A total of 12 locations were thus sampled for each mound. At each loca- tion, 1,980 cm samples of the surface (0-10 cm) material, including stones less than 50 mm in maximum diameter, were collected. At the mound-top locations, pits were dug and similar samples taken at 30-40 cm (Colorado sites) or at 40-50 and 80-90 cm (Oregon site). Samples were dry-sieved in the field to retain all stones greater than 8 mm in minimum diameter. In the laboratory the small-stone fraction was separated into two size classes, arbitrarily termed gravel (8-15 mm) and peb- bles (15-50 mm), and the numbers and masses of eafch of these components were de- termined. Because of heavy deposition of caliche in the Blanca South soil, samples of small stones were washed for 24 hr in concen- trated HCl before sorting and analysis. This was done to obtain the concentration of ele- ments influenced by the mound-forming mechanism, rather than by the pattern of caliche deposition. At the Oregon site samples for fine textural analysis were also taken at the three sampling depths at one mound-top location on each mound. These samples were analyzed by the standard Bouyoucos technique (Cox 1985) to 612 Great Basin Naturalist Vol. 47, No. 4 Table 1. Characteristics of Mima mounds from which soil and small stone samples were collected in north central Oregon (southern Wasco County) and south central Colorado (San Luis Valley and Sangre de Cristo Mountains). N Mean diameter (m) Maximum height (m) Location X ± SD Range X ± SD Range Oregon Lawrence Preserve Colorado Blanca South Mosca Flats Alpine Ridge 6 6 6 4 14.73 ± 2.63 12.21 ± 1.90 10.24 ± 1.49 11.92 ± 2.05 11.55-17.25 10.00-14.60 8.50-12.35 10.00-14.75 0.92 ± 0.12 0.25 ± 0.06 0.34 ± 0.06 0.56 ± 0.13 0.80-1.09 0.19-0.36 0.25-0.40 0.40-0.70 obtain percentages of sand, silt, and clay in the 2- mm soil fraction. For the Colorado sites, soil textural data for samples collected in an earlier study were supplied by J. D. Vitek. These samples were taken from 12.7-cm- depth zones from the surface to the maximum depth of the soil at six locations along a tran- sect crossing one mound at each site. The two end locations of each transect lay in the inter- mound zone and the four central locations on the mound surface. The percentages of sand, silt, and clay in the 2-mm fraction of these samples were also determined by the Bouyou- cos hydrometer technique. Data on the numbers and masses of small stones were analyzed by a three-factor ANOVA, using the BMDP8V statistical pro- cedure (Dixon and Brown 1979). In these analyses the three classification factors were size class, mound, and location (either hori- zontal position along the mound-intermound gradient or depth of mound-top samples). Data on fine textural composition were tested with a single-factor ANOVA. Results The mounds sampled at the Oregon site were greater in diameter and height than those at any of the Colorado sites (Table 1). In Colorado, mounds were lowest in elevation at the arid Blanca South site and increased in height, but not in diameter, with increasing elevation and precipitation. All mounds sam- pled were nearly circular in outline. Circular- ity ratios (rj were calculated from the area (a) and circumference (p) by the equation r^ = 4na/p" and ranged from 0.95 to 1.00. Mounds at all sites were composed of soil containing an abundance of small stones (mostly less than 50 mm in maximum diame- ter). Some larger stones were also present. Most of these were 5-10 cm in maximum diameter. At the Colorado sites these were often at the mouths of deep holes dug into the mounds by badgers {Taxidea taxus ) or coyotes {Canis latrans). The holes dug by these ani- mals were often deeper than the mound height, and digging thus brought to the sur- face large stones from the zone beneath the mound proper. In one instance, a rock frag- ment 24 cm long was found in the spoil heap of a presumed badger hole. In contrast, large stones, including partially exposed boulders more than 50 cm in diameter, were common in the intermound zones of all moundfields. Samples of soil and stones less than 50 mm in maximum diameter were sometimes difficult to obtain in the intermound zones because of the high density of these large stones. At the Lawrence Preserve, Oregon, data for variables relating to small-stone content varied significantly among the mounds sam- pled in almost all cases. However, several consistent patterns were noted along mound- intermound and mound-top depth gradients. Both total numbers and total masses of gravel and pebbles in the surface soil varied significantly along the mound-intermound gradient (Fo lo = 4.7 and 37.2 for number and mass, respectively; P < .05 and < .001 for number and mass, respectively), being great- est in the shallow intermound soils (Fig. 1). Between the edges and tops of mounds, how- ever, mean values for both number and mass increased, this increase being significant for mass (Fi 5 = 13.6, P < .05). This increase was greater for pebbles than gravel, as indicated by a size-place interaction term (F, 5 = 26.4, P < .01). Total mass of small stones also varied significantly with depth at the tops of mounds (F210 = 9.4, P < .01), being less at the October 1987 CoxETAL.: Mima Mounds 613 150- 120- E 90- 3 60- 30- 0 600f- 500- B 400- w w ^ 300- 200- 100 0 El Gravel □ Pebbles ■*: til Inter- mound Edge Top 0-10 cm Top 40-50 cm Top 80-90 cm Fig. 1. Total numbers and masses of gravel and pebbles in 1,980 cm^ soil samples from Mima mound tops (0-10, 40-50, and 80-90 cm depths), edges, and intermound zones at the Lawrence Memorial Grassland Preserve, Wasco County, Oregon. Four replicates were taken at each location on each of six mounds. intermediate depth than at either the surface or the greatest depth. Again, this variation was more pronounced for pebbles than for gravel (F^io = 18.1, P < .001), with pebbles showing more than a 1.5X increase in mass from intermediate depth to surface. Ratios of gravel numbers and masses to pebble numbers and masses in the surface soil at Lawrence Preserve, Oregon (Table 2), varied significantly along the mound- intermound gradient (Fg jo =12.8 and 15. 8 for numbers and masses, respectively; P < .01 and < .001, respectively), with the highest ratios being at the mound edge. Variation along the depth gradient at mound tops was significant only for ratios of masses (F2 jo — 614 Great Basin Naturalist Vol. 47, No. 4 Table 2. Mean gravel/pebble ratios for numbers and masses and mean masses of individual gravel and pebble elements from mound and intermound sites at the Lawrence Memorial Grassland Preserve, Oregon (n = 24 in all Location Depth Gravel/pebble ratio ± SE Mass ratio Number ratio Mean mass (g) ± SE Gravel Pebbles Mound top Mound top Mound top Mound edge Intermound 0-10 cm 40-50 cm 80-90 cm 0-10 cm 0-10 cm 0.316 ± 0.028 0.499 ± 0,0,58 0.564 ± 0.087 0.4.54 ± 0.036 0.221 ± 0.021 3.544 ± 0.244 6.1.58 ± 0.586 6.805 ± 0.806 5.232 ± 0.432 3.340 ± 0.279 0.792 ± 0.019 0.758 ± 0.029 0.724 ± 0.031 0.725 ± 0.023 0.820 ± 0.027 8.838 ± 0.517 9.795 ± 0.556 9.396 ± 0.597 8.575 ± 0.346 12.837 ± 0.525 rh 60 1 f] - g 40 Q. - [#1 ^ r,-: ^ Fin * fl ■•*." *1 - 20 0 °s >■'■■ ':- "■•'; n -^i r*i > 2 ^ 200 u :*• ■*? ■*■ fh ■i- * Hh rin ■«' 0 "*l r*" □ Pebbles 800 -t □ Gravel " "55 600 f^ CO pl- ptr ri- CO CO ^ 400 r# ^ Fh F# . •;"-= ■*- f* . ■"■'•. ';.-,. 200 . ^ *■ * [*i ^ $. -^f' -^ ^ *■ ■ ^ . -^ n -»* Int Edge Top Top 0-10 30-40 cm cm BLANCA SOUTH Int Edge Top Top 0-10 30-40 cm cm MOSCA FLATS Int Edge Top Top 0-1030-40 cm cm ALPINE RIDGE Fig. 2. Total numbers and masses of gravel and pebbles in 1,980 cm^ soil samples from Mima mound tops (0-10 and 30-40 cm depths), edges, and intermound zones at three locations in the San Luis Valley and Sangre de Cristo Mountains of southern Colorado. Six mounds were sampled at Blanca South and Mosca Flats, four at Alpine Ridge. Four replicates were taken at each location on each mound. 6.7, P < .05), with the ratios being greatest at the deepest level. At the Oregon site the mean mass of indi- vidual pebbles in the surface soil of inter- mound areas was about 1.4-1.5X that in mound soils (F,io = 26.2, P < .001). No October 1987 Cox ETAL.: Mima Mounds 615 T.-VBLE 3. Results of ANOVA tests of variables relating to small-stone content (gravel and pebbles) of mound and intermound soils at three locations in the San Luis Valley and Sangre de Cristo Mountains, Colorado. Surface positions are mound top, mound edge, and intermound; mound-top depth positions are 0-10 and 30-40 cm. Six mounds were sampled at Blanca South and Mosca Flats, four at Alpine Ridge. Test Blanca South Mosca Flats Alpine Ridge Numbers vs Sl'rf.\ce Position Among places (DF = 2, 10)* F = 28.2, P<.001 F = 14.3, P<.01 F = 9.5, P<.05 SizeXplace(DF = 2,10)* F = 16.1, P<. 001 F - 15.2, P<. 001 F = 9.3, P<.05 Masses vs Surface Position Among places (DF = 2,10)* F = 126.9, P<. 001 F 12.3, P<.01 F = 7.8, P<.05 SizeXplace(DF = 2,10)* F = 4.7, P< .05 F = 4.2, P<.05 NS Numbers vs Depth Among places (DF = l,5)t F = 89.1, P<. 001 NS NS Size X place (DF = l,5)t F = 85.5, P<. 001 NS NS Masses vs Depth Among places (DF = l,5)t F = 63.7, P<. 001 NS NS Size X place (DF = l,5)t NS F = 8.8, P<.05 NS *2.6 for Alpine Ridge 1 1,3 for Alpine Ridge Table 4. Ratios of gravel numbers and weights to pebble numbers and weights in soil samples from Mima mound tops (0-10 and 30-40 cm depths), edges, and intermound zones at three localities in the San Luis Valley and Sangre de Cristo Mountains, southern Colorado. Six mounds were sampled at Blanca South and Mosca Flats, four at Alpine Ridge. Values are derived from four replicates at each mound location. Ratio type Gravel/pebble ratio Locality Top (0-10 cm) Top (30-40 cm) Edge Intermound Blanca South Number * 7.155 ± 0.310 8.043 ±0.491 7.545 + 0.436 9.216 ± 0.577 (n = 24) Weight 0.756 ± 0.038 0.752 ± 0.045 0.837 ± 0.059 1.008 ± 0.105 Mosca Flats Number 8.352 ± 0.672 9.482 ± 0,486 7.438 ± 0.412 8.749 ± 0.721 (n = 24) Weight 0.950 ± 0.100 1.081 ± 0.088 0.799 ± 0.066 1.094 ± 0,116 Alpine Ridge Number 5.922 ± 0.216 8.017 ± 1.082 5.972 ± 0.437 5.894 ± 0.566 (n = 16) Weight 0.564 ± 0.024 0.553 ± 0.030 0.619 ± 0.052 0.630 ± 0.068 •DF = 3, 15. F = 2.43. P<.05 significant variation was noted with depth, however. Mean mass of individual gravel ele- ments did not vary greatly among sampling locations. For the Colorado sites, data on small-stone content also varied significantly among the mounds sampled for almost all variables, al- though less often for the Alpine Ridge site, where only four mounds were sampled. Nev- ertheless, clear patterns of increase in the concentration of both gravel and pebbles in the surface soil from intermound to mound top were evident at all sites, both for numbers and mass (Fig. 2). These trends were significant in all cases (Table 3) but were much stronger for the Blanca South and Mosca Flats sites than for Alpine Ridge, especially for the pebble component. Gravel and pebbles dif- fered significantly in the strength of this trend (size X place interaction. Table 3) in all but one case (mass data, Alpine Ridge), the ten- dency being for pebbles to show a greater overall increase in concentration. With only two exceptions (number and mass of gravel at Mosca Flats), mean values for concentration of gravel and pebbles were greater in the surface soil of mound tops than at a depth of 30-40 cm (Fig. 2). This tendency was significant only for Blanca South, how- ever (Table 3). Little significant variation of gravel/pebble ratios was noted for the Colorado sites (Table 4). Ratios of gravel and pebble numbers at Blanca South were greater in the intermounds 616 Great Basin Naturalist Vol. 47, No. 4 Table 5. Mean masses of individual gravel and pebbles in soil samples from Mima mound tops (0-10 and 30-40 cm depths), edges, and intermound zones at three localities in the San Luis Valley and Sangre de Cristo Mountains, southern Colorado. Six mounds were sampled at Blanca South and Mosca Flats, four at Alpine ridge. Values are derived from four replicate samples from each mound location. Locality Mean mass (g) ± SE Rock component Top (0-10 cm) Top (30-40 cm) Edge Intermound Blanca South (n = 24) Mosca Flats (n = 24) Alpine Ridge (n = 16) Gravel * Pebbles Gravel Pebbles Gravel Pebbles 0.714 ± 0.008 0.684 ± 0.009 0.706 ± 0.010 0.677 ± 0.010 6.866 ±0.198 7.460 ± 0.292 6.544 ± 0.238 6.683 ± 0.330 0.752 ± 0.056 0.684 ± 0.009 0.711 ± 0.008 0.728 ± 0.012 6.673 ± 0.310 6.420 ± 0,312 7.156 ±0.355 6.355 ± 0.347 0.707 ± 0.013 0.715 ± 0.009 7.490 ± 0.205 8.084 ± 0.290 0.718 ± 0.015 0.758 ± 0.026 7.117 ±0.360 7.269 ± 0.317 'DF 3,15, F ,3.56, P<. 05 Table 6. Soil textural data for mound depth profiles at the Lawrence Memorial Grassland Preserve, Oregon, and for mound and intermound locations at three sites in the San Luis Valley and Sangre de Gristo Mountains, southern Colorado. N Percent of 2-mm fraction ± SE Location Sand Silt Clay Lawrence Preserve, OR Mound top, 0-10 cm 6 34.2 + 3.1 43.8 ± 3.3 22.0 ± 0.3 Mound top, 30-50 cm 6 34.6 ± 3.2 41.9 ± 3.5 23.6 ±0.5 Mound top, 80-90 cm 6 31.8 ± 3.6 45.5 ± 4.2 22.7 ± 0.8 Blanca South, CO Intermound, 0-25.4 cm 4 63.6 + 2.0 21.0 ± 1.8 15.4 ± 0.3 Mound, 0-25.4 cm 8 62.5 ± 0.6 22.2 ± 0.6 15.2 ± 0.2 Mound, 25.4-50.8 cm 6 64.3 + 1.1 20.9 ± 1.0 14.6 ± 0.5 Mosca Flats, CO Intermound, 0-25.4 cm 2 62.5 + 0.1 21.3 ± 1.1 16.2 ± 1.0 Mound, 0-25.4 cm 8 61.7 + 0.6 20.3 ± 1.1 18.0 ± 0.7 Mound, 25.4-50.8 cm 4 58.8 + 1.1 18.6 ± 0.6 22.5 ± 1.5 Alpine Ridge, CO Intermound, 0-25.4 cm 4 63.8 + 2.0 26.0 ± 1,6 10.2 ± 0.5 Mound, 0-25.4 cm 8 75.2 + 1.4 14.2 ± 1.3 10.7 ± 0.2 Mound, 25.4-50.8 cm 3 71.3 ± 0.6 17.9 ± 0.8 10.9 ± 0.3 and in the deep zone of the mound top than in the surface soil of the mounds. Trends in mean values of gravel/pebble ratios were gen- erally similar for Mosca Flats and Alpine Ridge, but these patterns were not statisti- cally significant. Mean masses of individual gravel and pebble elements showed very little variation with sampling location at any of the sites (Table 5). Soil textural data from mound profiles at the Lawrence Preserve, Oregon, showed no con- sistent change with depth (Table 6), the tex- ture being that of a loam at all levels. At the Blanca South site in Colorado no clear pattern of mound-intermound or depth variation in texture was noted. Although both mound and intermound soils were sandy loams, samples from the upslope side of the mound and the adjacent intermound were significantly sandier (n = 8, x = 64.85%) than samples from the downslope portion of the mound (n = 12, x= 61.22%; t = 4.65, P < .001). At Mosca Flats the concentration of clay in the soil varied significantly (DF = 2,11; F = 6.74, P < .025) among sampling locations, being great- est in the deeper layers of the mound. Surface soil texture at this site was also a sandy loam. At Alpine Ridge texture also varied significantly among sampling locations (DF = 2,12; F = 13.52, P < .001 for sand), the October 1987 CoxETAL.: Mima Mounds 617 intermound soil having the highest concentra- tion of silt and the surface soil of the mound the highest concentration of sand. Discussion With respect to predictions of the three hypotheses of mound origin, the trends of increase in total concentrations of gravel and pebbles from mound edge to mound top at all locations support the fossorial rodent hypoth- esis. The low concentrations of gravel and pebbles in intermound areas at the three Col- orado sites also support this hypothesis. The very high concentrations of small rocks in the intermound areas at the Oregon site reflect only the shallowness of these soils over the weathering surface of the basalt bedrock. The increases in small-stone concentration from deep to surface layers of the mounds at the Colorado locations likewise support the fossorial rodent hypothesis, as does the in- crease in mass of small rocks from intermedi- ate depth to the surface of mounds at the Oregon site. The high surface concentrations of small stones suggest that movement of soil and small stones to the tops of mounds is being offset by erosional removal of soil fines. Thus, erosion now appears to be an agent of mound destruction. The significantly greater change in concen- tration of pebbles than of gravel along the mound-intermound gradient at Lawrence Preserve, Blanca South, and Mosca Flats, to- gether with the significant variation in the gravel/pebble number ratio at Lawrence Pre- serve, also supports the fossorial rodent hy- pothesis. In no instance, as predicted by the erosion and frost-sorting hypotheses, did the highest values of this ratio occur at mound tops. The trend of mean pebble mass at Lawrence Preserve also agrees with the pre- diction of the fossorial rodent hypothesis. In no case was a significant difference in mean pebble mass noted between mound top and mound edge, as predicted by the erosion and frost-sorting hypotheses. Soil textural data from Lawrence Preserve indicate that the mound soils are very high in silt and clay content, which reflects the high loess component of the mound parent mate- rial. The lack of strong textural sorting with depth suggests that the mound soils are kept well mixed by the activities of burrowing ani- mals. However, an argillic B horizon is evi- dent in at least some mounds of this region (R. Reider, personal communication). Our data are very similar to those obtained by Johnson (1982) at this same site. Johnson (1982), how- ever, noted that the intermound soils were somewhat sandier than those of the mounds. The texture of the intermound soil probably reflects the contribution of coarser compo- nents by weathering of the basaltic bedrock. At the Colorado sites texture was quite similar for both intermounds and mounds. The higher concentration of sand in mound-top soils at Alpine Ridge and the higher concen- tration of clay in the deeper mound soils at Mosca Flats, however, suggest that some dif- ferential removal of the finer textures occurs by wind and water erosion from the mounds. Thus, many of the observed patterns of small-rock composition support the fossorial rodent hypothesis, and none supports the ero- sion or frost-sorting hypothesis. Both small- stone concentration and soil textural patterns are also consistent with the hypothesis that erosion is presently a mechanism of mound degradation rather than development. Other evidence also argues strongly against freeze-thaw dynamics as a cause of mound formation. The suggestion that mounds may be remnant centers of ancient ice-wedge polygons (Kaatz 1959) is not supported by evi- dence of former permafrost, such as ice- wedge casts, from the vicinity of any present moundfield (Washburn 1980). The hypothesis that Mima mounds represent some sort of frost-sorting phenomenon is likewise not well supported by observations in any present-day periglacial environments. Most active sorted polygons lack central mounds of appreciable height and are less than 4 m in diameter (Washburn 1980). The largest sorted stone nets may reach 5-20 m in diameter and have a mounded center up to 1 m above the border- ing gutter, but such nets require that the com- mon large clasts in the soil system be 0.5-3.0 m in diameter (Goldthwaite 1976). Even these net dimensions are exceeded commonly in Mima mound fields, even though clasts of such size are rarely present. Recent models of the development of sorted polygons (Gleason et al. 1986), as well, suggest that the width of such polygons should be about 3.6X the depth of the active layer of the soil. For the very shallow soils of most Mima moundfields, this 618 Great Basin Naturalist Vol. 47, No. 4 relationship does not permit the formation of mound-intermound units of the order of 20-30 m or more in diameter. Finally, even the large sorted stone circles and nets associ- ated with Mima mounds on the Columbia Plateau have recently been attributed to the soil-mining activities of pocket gophers (Cox and Allen 1987). Thus, we conclude that periglacial hypotheses of Mima mound origin are conclusively falsified. Data on small-stone concentrations in mound and intermound soils at these Colum- bia Plateau and Rocky Mountain sites are sim- ilar to those of Cox and Gakahu (1986) for sites on the Pacific Coast from southern California to the Puget Lowlands of Washington. In all, data from eight Mima mound sites, spanning a wide range of climatic and geological settings, show a consistent pattern of concentration of the small-stone fraction in mound soils. In addition, all of these sites are consistent in showing highest gravel/pebble ratios at inter- mound or mound edge locations, rather than on mound tops, as predicted by physical hy- potheses of mound origin. Data for the Colorado sites differ from those of the Pacific Coast sites (Cox and Gakahu 1986) and our Oregon site in showing no varia- tion in mean pebble mass along the mound- intermound gradient. This apparently reflects the deficiency of heavy rock fragments with maximum diameters less than 50 mm in the intermound soils at the Colorado sites. Mean masses of pebbles at these locations ranged from 6.4 to 7.3 g (Table 5), compared to values of roughly 9- 14 g for intermound soils at other sites. The impetus for formation of Mima mounds by pocket gopher activity at Lawrence Pre- serve and Alpine Ridge sites is probably wa- terlogging of the shallow intermound soils during wet periods of the year. Intermound soils at these locations are shallow, and pre- cipitation levels are high enough that wet con- ditions are frequent, especially in spring. In these locations, as well, water erosion proba- bly exceeds wind erosion and may be the pri- mary physical factor limiting height develop- ment of the mounds. Selective erosional transport of silt and clay fractions from mounds to intermounds probably accounts for the sandier texture of mound-top soils at Alpine Ridge. The impetus for Mima mound formation at Blanca South, and perhaps Mosca Flats, must be somewhat different, however. Blanca South is the driest site at which Mima mounds have been recorded in North America. Al- though the mounds at this location are the lowest of those at the three Colorado sites examined in this study, they are as sharply defined and numerous as those at other Colo- rado sites. This suggests that the impetus for their formation is strong, but that their devel- opment in height is limited more severely by erosion. Wind erosion appears to be intense at this site, as suggested by the difference in sandiness of the upslope and downslope sides of the mound from which texture samples were obtained (Table 6). It is unlikely that waterlogged conditions are prevalent for significant periods at the Blanca South site, which receives less than 20 cm of precipitation annually. This site pos- sesses a thick, shallow caliche layer. In two intermound pits the surface of this layer lay at 29-36 cm. On unmounded alluvial flats im- mediately below the study area, rock-free, friable soil extended to a depth of 60 cm in a single test pit. Similarly, at Mosca Flats low annual precipitation and good drainage proba- bly prevent prolonged waterlogging of the soil (J. D. Vitek, personal communication). Shal- lowness of the surface soil, per se, seems to favor the formation of Mima mounds at these sites. The shallowness of intermound soils may expose pocket gophers to high predation risk by animals such as badgers and coyotes, or to exposure to severe winter cold, which characterizes the San Luis Valley. Because Mima mounds are absent from shallow desert soils within the range of pocket gophers in much of the Southwest, we suggest that the primary advantage of mounds at sites on the floor of the San Luis Vafley is reduction in exposure of pocket gophers to cold. In the deeper soils of mounds, these animals can locate their nests at deeper, more insulated levels. Acknowledgments Catherine MacDonald, Oregon Land Stew- ard for the Nature Conservancy, gave permis- sion for studies at the Lawrence Memorial Grassland Preserve and furnished back- ground information on this site. Annan Priday gave permission for sampling of mounds on October 198' CoxETAL.; Mima Mounds 619 property adjacent to the preserve. Donald B. Lawrence provided valuable advice on the work at the Lawrence Preserve. John D. Vitek provided extensive background infor- mation and unpublished data on soil textures for the Colorado sites and, together with Mark S. Gregory, assisted with field work at these locations. Malgorzata Zalejko carried out much of the laboratory analysis of samples from the Colorado sites. Richard Reider and John D. Vitek gave criticism and suggestions on an earlier draft of the manuscript. We thank all of these individuals for their help. This study was supported by NSF grant INT- 8420336 and by grant 211 187 from the San Diego State University Foundation. Lite MTU RE Cited Brunnschweiler, D 1962. The periglacial realm in North America during the Wisconsin glaciation. Biuletyn Peryglacjalny 11: 15-27. CoPELAND, W. N. 1980. The Lawrence Memorial Grass- land Preserve: a biophysical inventory with man- agement recommendations. Unpublished report (revised 1983), Oregon Chapter, Nature Conser- vancv, Portland, Oregon. Cox, G W 'l984a. Mounds of mystery. Nat. Hist. 9.3(6): 36-45. 1984b. The distribution of Mima mound grass- lands in San Diego County, California. Ecology 65: 1397-1405. 1985. Laboratory manual of general ecology. 5th ed. VVm. C. Brown Co., Dubuque, Iowa. Co.x, G W.. AND D W Allen 1987. Sorted stone nets and circles of the Columbia Plateau: a hypothesis. Northwest Sci. 61:179-185, Cox, G. W . AND C G Gakahu 1983. Mima mounds in the Kenya highlands: significance for the Dalquest-Scheffer hvpothesis. 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TYPE SPECIMENS OF RECENT MAMMALS IN THE UTAH MUSEUM OF NATURAL HISTORY, UNIVERSITY OF UTAH' Eric A. Rickart" Absteuct — A detailed list of holotypes of Recent mammals housed in the Utah Museum of Natural History is presented. The collection of Recent mammals at the Utah Museum of Natural History includes more than 28,500 cataloged specimens. Among these are 40 holotypes of Utah mam- mals deposited over a 25-year period. As part of a current project to renovate and computer- ize the entire mammal collection, this paper presents the first published list of type speci- mens. Taxa are arranged following Hall (1981). Each entry includes the name as originally proposed, followed by the original reference and date of publication. Age, sex, nature of specimen. University of Utah (UU) catalog number, type locality, date of collection, col- lector(s), original number, and standard ex- ternal measurements follow in order. This in- formation was verified against previous citations (Durrant 1952, Miller and Kellogg 1955, Hall 1981) and the original specimen labels. Changes in nomenclature or taxo- nomic status, corrections of erroneous infor- mation, and notes on current condition of the specimen are listed under Remarks. Lagomorpha Ochotonidae Ochotona princeps barnsei Durrant & Lee, Proc. Biol. Soc. Washington 68:6, 20 May 1955. Holotype. — Adult male, skin and skull, UU 8140, from Johnson's Reservoir, 15 mi N Loa, 8,800 ft, Sevier Co., Utah; obtained 23 August 1952 by M. R. Lee, original num- ber 123; measurements: 20-[?]-32-25. Ochotona princeps lasalensis Durrant & Lee, Proc. Biol. Soc. Washington 68:4, 20 May 1955. Holotype. — Adult male, skin and skull, UU 6409, from Warner Ranger Station, La Sal Mountains, 9,750 ft. Grand Co., Utah; obtained 23 June 1948 by K. R. Kelson, origi- nal number 531; measurements: 178-6-30-23. Remarks — Cheek teeth loose. Ochotona princeps wasatchensis Durrant & Lee, Proc. Biol. Soc. Washington 68:2, 20 May 1955. Holotype. — Adult male, skin and skull, UU 4787, from 10 mi above lower pow- erhouse, road to Cardiff Mine, Big Cotton- wood Canyon, Salt Lake Co., Utah; obtained 24 June 1946 by J. Berryman, original number 1; measurements: 240-3-31-23, 158 g. RODENTIA Sciuridae CiteUus leucurus escalante Hansen, J. Mammal. 36:274, 26 May 1955. Holotype — Adult female, skin and skull, UU 9195, from 2 mi SE Escalante, 5,400ft, Garfield Co., Utah; obtained 19 August 1953 by M. R. Lee, origi- nal number 493; measurements: 225-59-40- 13. Remarks. — Placed in the genus Am- mospennophilus (Hall 1981). Occipital and frontal regions damaged. CiteUus leucurus notom Hansen, J. Mam- mal. 36:274, 26 May 1955. Holotype.— Adult male, skin and skull, UU 9919, from Notom, Wayne Co., Utah; obtained 2 July 1936 by D. E. Beck, original number 5288N; mea- surements: 215-68-41-[?]. Remarks. — Placed in the genus Ammospermophilus (Hall 1981). Right mandible incomplete, left zygomatic arch broken. CiteUus variegatus robustus Durrant & Hansen, Proc. Biol. Soc. Washington 67:264, 15 November 1954. Holotype. — Adult 'UMNH Contribution No. 87-4. ^Utah Museum of Natural History, University of Utah, Salt Lake City. Utah 84112. 620 October 1987 RicKART: Utah Museum Mammal Types 621 female, skin and skull, UU 7668, from Pass Creek, Deep Creek Mountains, 8,000 ft, Juab Co., Utah; obtained 5 June 1950 by R. M. Hansen, original number 188; measurements: 556-211-64-27. Remarks— Placed under the name Spennophilus (Hall 1981). Sciurus aberti navajo Durrant & Kelson, Proc. Biol. Soc. Washington 60:79, 2 July 1947. HOLOTYPE. — Adult male, skin and skull, UU 4775, from 1 mi E Kigalia Ranger Station, 30 mi W Blanding, Natural Bridges National Monument Road, 8,000 ft, San Juan Co., Utah; obtained 10 September 1946 by G. F. Edmunds and I. B. McNulty, original number 2452 of S. D. Durrant; measure- ments: 486-220-74-31. Remarks— Consid- ered a synonym of S. a. aberti (HoflFmeister and Diersing, J. Mammal. 59:408, 30 May 1978). Tamiasciurus fremonti dixiensis Hardy, Proc. Biol. Soc. Washington 55:87, 25 June 1942. HOLOTYPE. — Adult male, skin and skull, UU 4374, from near Further Water, Dixie National Forest, Pine Valley Moun- tains, ca 9,500 ft, Washington Co., Utah; ob- tained 23 August 1941 by O. Hall and R. Hardy, original number 2223 of Hardy; mea- surements: 339-131-53-28. Remarks— Ar- ranged as T. hudsonicus dixiensis (Hardy, Proc. Biol. Soc. Washington 63:13, 26 April 1950). Glaucomys sabrinus murinauralis Musser, Proc. Biol. Soc. Washington 74:120, 11 Au- gust 1961. HOLOTYPE. — Adult male, skin, skull, and postcranial skeleton, UU 15652, from Timid Springs (SW 1/4, NE 1/4, Sec 7, T29S, R4W), 1 mi N Big Flat Guard Station, Tushar Mountains, 10,300 ft, Beaver Co., Utah; obtained 15 August 1960 by G. G. Musser, original number 1232; measure- ments: 329-155-42-30, 126 g. Geomyidae Thomomys talpoides durranti Kelson, Proc. Biol. Soc. Washington 62:143, 23 Au- gust 1949. HOLOTYPE. — Adult female, skin and skull, UU 5603, from Johnson Creek, 14 mi N Blanding, 7,500 ft, San Juan Co., Utah; obtained 20 May 1947 by K. R. Kelson, origi- nal number 201; measurements: 215-64-28-8. Thomomys talpoides oquirrhensis Dur- rant, Bull. Univ. Utah 30(5):3, 24 October 1939. HOLOTYPE. — Adult male, skin and skull, UU 2605, from Settlement Creek, Oquirrh Mountains, 6,500 ft, Tooele Co., Utah; obtained 11 June 1938 by S. D. Dur- rant, original number 1461; measurements: 203-55-28-6. Thomomys talpoides wasatchensis Dur- rant, Publ. Mus. Nat. Hist., Univ. Kansas 1:8, 15 August 1946. Holotype. — Adult male, skin and skull, UU 1604, from Midway, 5,500 ft, Wasatch Co., Utah; obtained 1 Sep- tember 1936 by S. D. Durrant, original num- ber 1049; measurements: 233-75-31-8. Thomomys bottae bonnevillei Durrant, Publ. Mus. Nat. Hist., Univ. Kansas 1:41, 15 August 1946. Holotype. — Adult male, skin and skull, UU 3576, from Fish Springs, 4,400 ft, Juab Co., Utah; obtained 8 June 1940 by S. D. Durrant, original number 1955; mea- surements: 221-62-30-6. Remarks. — Ar- ranged as T. umbrinus bonnevillei (Hall 1981). Thomomys bottae contractus Durrant, Publ. Mus. Nat. Hist., Univ. Kansas 1:50, 15 August 1946. Holotype. — Adult male, skin and skull, UU 1851, from Scipio, 5,315 ft, Millard Co., Utah; obtained 17 September 1936 by S. D. Durrant, original number 1125; measurements: 255-85-33-8. Remarks. — Ar- ranged as T. umbrinus contractus (Hall 1981). Thomomys bottae convexus Durrant, Proc. Biol. Soc. Washington 52:159, 11 October 1939. Holotype. — Adult male, skin and skull, UU 2482, from E side Clear Lake, 4,600 ft, Millard Co., Utah; obtained 20 May 1938 by S. D. Durrant, original number 1401; mea- surements: 206-58-27-4. Remarks. — Ar- ranged as T. umbrinus convexus (Hall 1981). Cheek teeth loose. Thomomys bottae nesophilus Durrant, Bull. Univ. Utah 27(2):2, 3 October 1936. Holotype. — Adult male, skin and skull, UU 1136, from Antelope Island, Great Salt Lake, Davis Co. , Utah; obtained 20 April 1935 by S. D. Durrant, original number 761; measure- ments: 222-60-32-6. Remarks. — Arranged as T. umbrinus nesophilus (Hall 1981). Left coronoid process broken. Thomomys bottae powelli Durrant, Proc. Biol. Soc. Washington 68:79, 3 August 1955. HOLOT\TE. — Adult female, skin and skull, UU 7955, from Hall Ranch, Salt Gulch, 8 mi W Boulder, 6,000 ft, Garfield Co., Utah; ob- tained 7 August 1951 by S. D. Durrant, origi- nal number 2578; measurements: 232-65-32- 5. Remarks. — Arranged as T. umbrinus 622 Great Basin Naturalist Vol. 47, No. 4 powelli (Hall 1981). Thomomys bottae robustus Durrant, Publ. Mus. Nat. Hist., Univ. Kansas 1:30, 15 Au- gust 1946. HOLOTYPE. — Adult male, skin and skull, UU 2726, from Orr's Ranch, Skull Val- ley, 4,300 ft, Tooele Co., Utah; obtained 19 June 1938 by S. D. Durrant, original number 1583; measurements: 226-65-31-5. RE- MARKS.— Arranged as T. umhrinus robustus (Hall 1981). Thomomys bottae sevieri Durrant, Publ. Mus. Nat. Hist., Univ. Kansas 1:45, 15 Au- gust 1946. HOLOTYPE. — Adult female, skin and skull, UU 2530, from Swasey Spring, House Mountains, 6,500 ft, Millard Co., Utah; obtained 16 May 1938 by S. D. Dur- rant, original number 1380; measurements: 200-58-28-4. Remarks. — Arranged as T. um- brinus sevieri (Hall 1981). Cheek teeth loose. Thomomys bottae stansburyi Durrant, Publ. Mus. Nat. Hist., Univ. Kansas 1:36, 15 August 1946. HoLOTYPE. — Adult female, skin and skull, UU 2045, from South Willow Creek, Stansburv Mountains, 7,500 ft, Tooele Co., Utah; obtained 2 July 1937 by O. S. Walsh and S. D. Durrant, original number 1257 of Durrant; measurements: 209-49-28-5. Remarks. — Arranged as T. umbrinus sta^is- Z?wn/i (Hall 1981).^ Thomomys bottae tivius Durrant, Bull. Univ. Utah 28(4):5, 18 August 1937. HOLO- TYPE.— Adult female, skin and skull, UU 1827, from Oak Creek Canyon, 6 mi E Oak City, 6,000 ft, Millard Co., Utah; obtained 14 September 1936 by S. D. Durrant, original number 1100; measurements: 215-69-30-6. Remarks. — Arranged as T. umbrinus tivius (Hall 1981). Thomomys bottae wahwahensis Durrant, Bull. Univ. Utah 28(4):3, 18 August 1937. HoLOTYPE. — Adult male, skin and skull, UU 1750, from Wah Wah Springs, 30 mi W Mil- ford, 6,500 ft, Beaver Co., Utah; obtained 22 July 1936 by S. D. Durrant, original number 989; measurements: 220-63-29-5. Re- marks.— Arranged as T. umbrinus wahwa- hensis (Hall 1981). Right coronoid process broken. Heteromyidae Perognathus parvus bullatus Durrant & Lee, Proc. Biol. Soc. Washington 69:183, 31 December 1956. Holotype. — Adult male, skin and skull, UU 8771, from Ekker's Ranch, Robbers Roost, 25 mi (airline) E Hanksville, 6,000 ft, Wayne Co., Utah; obtained 18 May 1951 by J. Bushman, original number 54; measurements: 160-85-22-8. Microdipodops megacephalus leucotis Hall & Durrant, Murrelet 22:6, 30 April 1941. Holotype. — Adult female, skin and skull, UU 3525, from 18 mi SW Orr's Ranch, 4,400 ft, Tooele Co., Utah; obtained 6 June 1940 by S. D. Durrant, original number 1904; mea- surements: 142-75-24-9. Remarks. — Bullae broken. Dipodomys ordii celeripes Durrant & Hall, Mammalia 3:10, March 1939. Holotype. — Adult male, skin and skull, UU 1956, from Trout Creek, 4,600 ft, Juab Co., Utah; ob- tained 5 May 1937 by S. D. Durrant, original number 1168; measurements: 225-126-41-13. Remarks — Left bulla broken. Dipodomijs ordii cinderensis Hardy, Proc. Biol. Soc. Washington 57:53, 31 October 1944. Holotype. — Adult male, skin and skull, UU 4611, from sandy soil immediately north of the northern of two large cinder cones, Diamond Valley, 10 mi N St. George, Washington Co., Utah; obtained 13 February 1944 by R. Hardy, original number 2690; measurements: 232-124-38-14. Dipodomys ordii pallidas Durrant & Set- zer. Bull. Univ. Utah35(26):24, 30 June 1945. Holotype. — Adult male, skin and skull, UU 3526, from Old Lincoln Highwav, 18 mi SW Orr's Ranch, Skull Valley, 4,400 ft, Tooele Co., Utah; obtained 6 June 1940 by S. D. Durrant, original number 1905; measure- ments: 240-138-40-14. Remarks.— Left bulla broken. Dipodomys ordii panguitchensis Hardy, Proc. Biol. Soc. Washington 55:90, 25 June 1942. Holotype, — Adult male, skin and skull, UU 4375, from 1 mi S Panguitch, 6,666 ft, Garfield Co., Utah; obtained 31 August 1940 by R. Hardy, original number 2151; measurements: 257-145-41-14. Dipodomys ordii sanrafaeli Durrant & Set- zer. Bull. Univ. Utah35(26):26, 30 June 1945. Holotype. — Adult female, skin and skull, UU 4612, from 1.5 mi N Price, 5,567 ft. Car- bon Co., Utah; obtained 5 June 1940 by R. Hardy and H. Higgins, original number 1901 of Hardy; measurements: 249-138-42-16. Dipodomys microps woodburyi Hardy, Proc. Biol. Soc. Washington 55:89, 25 June 1942. Holotype. — Adult male, skin and October 1987 RiCKART: Utah Museum Mammal Types 623 skull, UU 4376, from Clistoyucca area on Beaverdam Slope west of Beaverdam Moun- tains, ca 3,500 ft, Washington Co., Utah; ob- tained 19 October 1940 by R. Hardy, original number 2169; measurements: 302-177-43-14. Remarks. — Considered a synonym of D. m. celsiis (Stock, J. Mammal. 51:431, 20 May 1970). Castoridae Castor canadensis duchesnei Durrant & Crane, Univ. Kansas Publ., Mus. Nat. Hist. 1:413, 24 December 1948. Holotype. — Young adult male, skin and skull, UU 4625, from Duchesne River, 10 mi NW Duchesne, 5,600 ft, Duchesne Co., Utah; obtained 23 September 1946 by D. Thomas, original num- ber 160 of K. R. Kelson; measurements: 1176- 458-165-33, 26 lbs. Castor canadensis pallidus Durrant & Crane, Univ. Kansas Publ., Mus. Nat. Hist. 1:409, 24 December 1948. HOLOTtTE — Adult female, skin and skull, UU 719, from Lynn Canyon, 7,500 ft. Box Elder Co., Utah; obtained 7 September 1932 by W. W. Newby and A. M. Woodbury, original number 762a; measurements: 1040-380-157-35. Castor canadensis rostralis Durrant & Crane, Univ. Kansas Publ., Mus. Nat. Hist. 1:411, 24 December 1948. HOLOTYPE — Young adult male, skin and skull, UU 5199, from Red Butte Canyon, Fort Douglas, 5,000 ft, Salt Lake Co., Utah; obtained 13 October 1947 by H. S. Crane and CM. Greenhalgh, original number 446 of Crane; measurements: 1330-470-170-34. Cricetidae Peromyscus boijlii utahensis Durrant, Proc. Biol. Soc. Washington 59:167, 23 De- cember 1946. Holotype. — Adult female, skin and skull, UU 4400, from 1/2 mi above lower power station, Millcreek Canyon, 5,800 ft, Salt Lake Co., Utah, obtained 15 November 1941 by H. W. Setzer, original number 297; measurements: 188-102-20-16. Remarks. — Type locality given in original description in- correctly reads "5 miles above ..." (Durrant 1952). Neotoma lepida sanrafaeli Kelson, J. Washington Acad. Sci. 39:418, 15 December 1949. Holotype. — Adult male, skin and skull, UU 6428, from Rock Canyon Corral, 5 mi SE Valley City, 4,500 ft. Grand Co., Utah; obtained 20 June 1948 by K. R. Kelson, origi- nal number 522; measurements: 312-128-34- 30. Remarks. — Hall (1981) incorrectly gives 9 January 1950 as the date of publication. Neotoma cinerea macrodon Kelson, J. Washington Acad. Sci. 39:417, 15 December 1949. Holotype. — Adult male, skin and skull, UU 4725, from E side confluence Green and White rivers, 1 mi SE Ouray, 4,700 ft, Uintah Co. , Utah; obtained 21 August 1946 by K. R. Kelson, original number 120; measure- ments: 372-158-38-36. Microtus longicaudus incanus Lee & Dur- rant, Proc. Biol. Soc. Washington 73:168, 30 December 1960. Holotype. — Adult male, skin and skull, UU 14286, from 1/4 mi SE Burned Ridge, Mount Ellen, Henry Moun- tains, 10,300 ft, Garfield Co., Utah; obtained 10 September 1957 by M. R. Lee, original number 1512; measurements: 178-55-22-14. Microtus richardsoni myodontus Ras- mussen & Chamberlain, J. Mammal. 40:54, 20 February 1959. Holotype. — Adult male, skin and skull, UU 13084, from top of ridge, head of Boulger Canyon, 2 mi NE Huntington Reservoir, Wasatch Plateau, 10,000 ft, San- pete Co., Utah; obtained 6 July 1956 by D. I. Rassmussen, original number 143; measure- ments: 231-74-25-17. Lagurus curtatus orbitus Dearden & Lee, J. Mammal. 36:271, 26 May 1955. Holo- Ti'PE. — Adult female, skin and skull, UU 9077, from Steep Creek, 15 mi N Boulder, 8,500 ft, Garfield Co., Utah; obtained 8 July 1953 by M. R. Lee, original number 291; measurements: 133-17-16-12. Zapodidae Zapus princeps chrysogenys Lee & Dur- rant, Proc. Biol. Soc. Washington 73:171, 30 December 1960. HoLOT\TE. — Adult male, skin and skull, UU 13834, from 2.5 mi NE La Sal Peak, La Sal Mountains, 8,500 ft, Grand Co., Utah; obtained 17 July 1956 by M. R. Lee, original number 1436; measurements: 232-139-31-14. 624 Great Basin Naturalist Vol. 47, No. 4 Literature Cited Hall, E R I981. The mammals of North America. 2d ed. John Wiley, New York. 1: xv + 1-600 + 90, 2: vi + 601-1181 + 90. Durrani, S. D. 1952. The mammals of Utah, taxonomy Miller, G. S., and R. Kellogg. 1955. List of North and distribution. Pub. Mus. Nat. Hist., Univ. American Recent mammals. Bull. U.S. Nat. Mus. Kansas 6:1-549. 205; xii + 1-954. AVIAN USE OF SCORIA ROCK OUTCROPS Mark A. Rumble' Abstract. — Avian use of scoria outcrop habitats was compared to use of sagebrush (Artemisia spp.Vgrassland habitats. Outcrop habitats exhibited higher species richness, total population density, density of lark sparrows (Chondestres grarnmacus), and density of rock wrens (Salpinctes obsoletus). Western meadowlarks {Sttirnella ne- glecta) and vesper sparrows (Pooecetes gramineiis) were more abundant in sagebrush/grassland habitats than in scoria outcrops. Habitat relationship models indicated that the unique plant community and structural diversity provided by the scoria outcrops were correlated with increased avian use. Because of requirements that areas surface- mined for coal and other minerals be re- claimed to the original productivity found prior to mining (e.g., Surface Mining Control and Reclamation Act 1977, numerous state laws), regulatory agencies and mining compa- nies have sought a variety of habitat improve- ment techniques for reclaiming surface- mined lands for wildlife. Recently, attention has focused on the use of rocks, rock piles, and rock outcrops to enhance wildlife habitats, but little is known about the effectiveness of these or many other mitigation practices on mined lands (Evans 1982). Scoria (fused porcellanite) outcrops occur in native sagebrush/grassland habitats through- out the Powder River Basin in northeastern Wyoming and southeastern Montana. These outcrops resulted from erosion of soil that cov- ered burned-out coal seams near the surface. Several relatively mesic tree and shrub spe- cies are associated with these outcrops. These include ponderosa pine {Pinus ponderosa ), juniper (Jiitiipenis spp.), skunkbush sumac {Rhus trilobata), currant (Ribes spp.), and chokecherry {Prunus virginiana). Increased patchiness of vegetation in shrub communities has been shown to be associated with increased numbers of avian species (Roth 1976). Rotenberry and Wiens (1980a) re- ported that avian abundance and species di- versity in shrubsteppe communities were as- sociated with habitat heterogeneity. Maser, Geist et al. (1979) and Maser, Thomas et al. (1979) noted the importance of rocks, cliffs, talus, outcrop, and man-made rock piles as wildlife habitat. Wiens and Rotenberry (1981) also noted a unique avifauna associated with rocky outcrops. Otherwise, little information can be found to quantify the importance of outcrop habitats to avian species. The objectives of this study were (1) to esti- mate the densities of avifauna associated with scoria outcrop habitats and compare them with densities in the sagebrush/grassland habitats, and (2) to evaluate the habitat associ- ations of the avifauna that use these habitats. Study Area and Methods This study was conducted approximately 10 km north of Decker, Montana, on land under lease by the Decker Coal Company. The veg- etation of the area is classified as eastern Mon- tana ponderosa pine-savannah, which con- sists of scattered stands of ponderosa pine with broad expanses of northern mixed prairie (Payne 1973). Scoria outcrops were locally abundant and supported a unique plant com- munitv of relativelv more mesic shrub species (Biggins et al. 1985). Thirty-eight study sites, 19 in scoria out- crop habitats and 19 in sagebrush/grassland habitats, were located and permanently marked. Outcrop study plots were selected to represent the full range of available outcrop habitats (few to many and small to large out- crops). Sagebrush/grassland habitats were se- lected for similarity of vegetation to the scoria outcrop plots, ignoring the direct influences of the outcrops on vegetation. Vegetation on the sagebrush/grassland plots generally USDA Forest Service, Rocky Mountain Forest and Range Experiment Station. South Dakota School of .Mines and Technolog\, Rapid City, South Dakota 57701. (Station's headquarters is in Fort Colhns, Colorado, ni cooperation with Colorado State University.) 625 626 Great Basin Naturalist Vol. 47, No. 4 Table 1. Average (± se) densities (birds per ha) and species richness of birds occupying scoria rock outcrop and sagebrush/grassland habitats. Sagebrush/ Significance Species Scoria outcrop grassland level"" Lark sparrow Western meadowlark'' 3.8 ± 0.4 0.3 ± <0.1 0.2 ± 0.1 0.4 ± 0.1 ** * Brewer's sparrow Vesper sparrow Rock wren 0.1 ± <0.1 <0.1 ± <0.1 0.2 ± <0.1 0.2 ± 0.1 0.1 ± <0.1 0.0 NS ** ** Total density Species richness 5.2 ± 0.4 4.5 ± 0.3 1.4 ± 0.2 3.1 ± 0.3 ** ** "*P £ . 10, ** P s .05 based on two-tailed t-test, NS not significant, ''Density was calculated based on the number of individuals within 50 m of the census point. consisted of scattered sagebrush {Artemisia tridentata and A. cana) with a grass under- story consisting of bluebunch wheatgrass {Agropyron spicatwn), needle and thread {Stipa comata), and threadleaf sedge {Carex filifolia). Avian counts were made from a variable circular plot (Reynolds et al. 1980) located at the center of each site. Birds were counted for three consecutive mornings at three-week in- tervals from mid-May through June 1984-85 (nine counts each year). Upon arriving at a census point, observers waited for one minute and then conducted the census for the next six minutes. Distances to birds seen or heard were estimated to the nearest m out to 30 m and to the nearest 5 m beyond 30 m. Densities of lark sparrows, rock wrens, and total birds were estimated using the Fourier series pro- cedures described for point transects of grouped data (Burnham et al. 1980). Variance estimates were obtained indirectly (Burnham et al. 1980:54). This method of estimating variances assumes that sample points are in- dependent. Sample points were located be- tween 200 m and several km apart and were usually located in habitats discontinuous with the next closest sample point. Because of lim- ited data or sighting functions that did not conform to the assumptions of line transect theory (Burnham et al. 1980), western mead- owlark, vesper sparrow, and Brewer's spar- row {Spizella breweri) densities were esti- mated from the average number of individuals within 50 m of the sampling point. Density estimates from fixed radius plots assume that the probability of detection in plots equals one. This assumption was probably violated for meadowlarks. Several methods were used to estimate habitat characteristics. Herbaceous vegeta- tive cover was estimated by species in thirty 20 X 50-cm quadrats spaced at 1-m intervals along each of three transects radiating from the plot center (Daubenmire 1959); the start- ing point on each transect was selected ran- domly. Density of shrub species was esti- mated by counting all shrubs in a 50 X 50-m subplot centered over the study plots. All rocks and outcrops within a 50-m radius of the plot center and taller than 0.5 m were counted; thereafter, height, width, and length were measured to the nearest dm. Mean densities of bird species and total birds, and species richness (number of spe- cies) were compared between outcrop and sagebrush/grassland habitats using two-tailed t-tests (Steele and Torrie 1960). Species diver- sity was calculated using the Shannon-Wiener method for all observations within 50 m of the census point. Similarity in abundance of avian species between outcrop and sagebrush/ grassland habitats was compared using Soren- son's index. Habitat relationships were tested using stepwise forward-backward multiple re- gression for all species except rock wrens. The dependent variable was the estimated density of each species for a plot. Stepwise forward- back-ward discriminant function analysis (Nie et al. 1975) was used to evaluate rock wren habitat relationships due to the presence- absence nature of their distribution on study plots. Classification functions from discrimi- nant analysis were evaluated using the jack- knife procedure in BMDP7M (Dixon et al. 1983). The following variables were used in the habitat analyses: percentages of total veg- etative cover, grasses, forbs, bare ground, lit- ter, threadleaf sedge, bluebunch wheatgrass, cheatgrass {Bromus spp.), needle and thread, and cactus {Opuntia spp.); densities of sage- brush and skunkbush sumac; densities and October 1987 RuMBLE: Avian Habits 627 Table 2. Habitat variables associated with avian use of rock outcrop and sagebrush/grassland habitats near Decker, Montana." Species Independent variables Standardized coefficient Percent variation explained Correlation coefficient Rock wren Density of rocks > I.O i n in height 0.61 64.0 0.71 Avg. height of rocks 0.59 71.9 0.58 Lark sparrow Avg. height of rocks 0.78 67.2 0.82 % cover of cactus -0.16 69.8 -0.37 Brewer's sparrow Density of sagebrush 0.41 17.2 0.41 Total density Avg. height of rocks 0.56 58.2 0.76 % herbaceous cover -0.20 61.9 -0.40 Vol. of rocks > 1.0 m in height 0,23 65.3 0.60 Species richness Vol. of rocks > 1.0 m in height 0.45 31.7 0.56 % cover of needle and thread -0.38 44.6 -0.52 "Variables were selected iisiiiK stepwise forward-backward multiple regression except i was used. ck wrens tor which stepwise forward-backward discriminant analysis volumes of outcrops taller than 0.5 m; and densities and volumes of outcrops taller than 1.0 m. Regression equations were limited to those variables that reduced the sums of squares significantly at P < .05, and discrimi- nant analysis was limited to those variables that contributed at least 5% to Wilk's lambda. Results Avian Abundance Higher total bird densities (P < .05) and higher average species richness were found on the scoria outcrop study plots compared with the sagebrush/grassland plots (Table 1). When summed over all plots, 23 species were counted within 50 m of the census points in the outcrop plots versus 10 on the sagebrush/ grassland plots. Based on Sorenson's index, there was 19% similarity in the pooled species abundance between the outcrop and sage- brush/grassland habitats. Lark sparrows made up approximately 80% of the total observa- tions in outcrop habitats, and their density on the outcrop plots was nearly 20 times greater than in the sagebrush/grassland plots. Rock wrens were found only in the outcrop habi- tats, although densities were relatively low. Densities of western meadowlark were greater on the sagebrush/grassland plots than on the outcrop plots (P < . 10), as were vesper sparrow densities (P < .05). Brewer's sparrow densities were higher on the sagebrush/grass- land plots, but the difference was not signifi- cant (P = .38). Species diversity in the scoria outcrop habitats (1.83) was less than in sage- brush/grassland habitats (2.70) because of lark sparrow dominance in the former. Species evenness (Pielou 1975:15) in the outcrop habi- tats was 0.40 versus 0.78 in the sagebrush/ grassland habitats. Habitat Relationships Discriminant analysis of plots with rock wrens present versus those without indicated that two variables were important in discrimi- nating (P < .01) between the groups and ac- counted for 72% of the variation between groups (Table 2). Both of these variables char- acterized attributes of the scoria outcrops. The density of outcrops taller than 1.0 m ac- counted for 64% of the variation, while aver- age height of outcrops taller than 0.5 m con- tributed an additional 8%. Both variables had high positive simple correlations with rock wren abundance. Classification functions cor- rectly reclassified 92% of the study plots into the correct group; two study plots without wrens were classified as suitable habitat, and one with wrens was classified as unsuitable habitat. Two variables, average height of rock out- crops taller than 0.5 m (P < .05) and percent cover of cactus (P < . 10), explained 70% of the variation in the density of lark sparrows on study plots. Average height of rocks was posi- tively associated with the density of lark spar- rows; cactus was negatively associated with lark sparrow density. Only one variable, sage- brush density, contributed significantly (P < 628 Great Basin Naturalist Vol. 47, No. 4 .05) to the reduction in the sums of squares (17%) of Brewer's sparrow densities on the study plots. Three variables, average height of out- crops, percent total herbaceous cover (P < .05), and volume of outcrops taller than 1.0 m (P < .10), were entered into the model for total avian density on study plots. Average height of the outcrops was positively associ- ated with total avian density and was entered first in the model, accounting for 58% of the variation in bird abundance. Total herbaceous cover, which was negatively associated with total avian density, was entered next; volume of outcrops taller than 1.0 m, which was posi- tively associated with total density, was en- tered last. Each of these latter two variables added an additional 3% to the total variation accounted for by the model. Volume of outcrops taller than 1.0 m and percent cover of needle and thread explained 45% of the variation (P < .05) in species rich- ness. Volume of the outcrops taller than 1.0 m was positively associated with species rich- ness, while percent cover of needle-and- thread grass was negatively associated with species richness. No significant habitat rela- tionships were found for western mead- owlarks or vesper sparrows. Discussion Scoria rock outcrops provide a unique habi- tat in this shrubsteppe region. Shrub species such as skunkbush sumac, chokecherry, cur- rant, and juniper are not found except in asso- ciation with the scoria outcrops in this ecosys- tem. The occurrence of these shrub species was probably related to shading, protection from wind, snow drift accumulation, and mulch effects of the rocks (Biggins et al. 1985). Rock wrens, as expected, were confined to some of the scoria outcrop habitats. Some out- crop study plots did not support rock wrens, presumably because of limited foraging areas or lack of crevices for nesting. Rock wrens selected the habitats with larger outcrops. Study plots with rock wrens had an average of 9.3 outcrops per ha that were taller than 1.0 m and an average height of 0.8 m. These aver- ages can be somewhat misleading in that plots with rock wrens generally had several out- crops 2.0 m or greater in height with numer- ous smaller, sometimes single, rocks. Classifi- cation of rock wren habitats, based on these criteria, suggests that all suitable habitats for rock wrens were not filled. Wiens and Roten- berry (1981) reported high variation in local avian population densities which may have indicated "unfilled ' habitats. Both of the "un- filled habitats in the present study were rela- tively smaller and isolated from contiguous outcrop areas and thus may not have been large enough to meet the habitat require- ments of wrens. Alternatively, other parame- ters not measured in this study may have lim- ited rock wren distributions (i.e., the remaining 28% of variance not accounted for by the discriminant analysis). Renaud (1979) reported rock wrens in most eroded bedrock outcrops in Saskatchewan. Average height of outcrops and percent cover of cactus were probably not the habitat features to which lark sparrows were respond- ing. Skunkbush sumac was closely associated with average height of outcrops (r = .75). In general, larger outcrops had larger sumac and other shrubs associated with them, and lark sparrows used these shrubs for perching, singing, and nesting. Skunkbush sumac was the most common shrub in the outcrop habi- tats, and lark sparrows showed a high positive association with sumac density (r = .70). Lark sparrows also used areas occupied by tall, dense sagebrush within the study area, proba- bly because of the increased structural habitat diversity. Wiens and Rotenberry (1981) re- ported that lark sparrows were correlated with shrub cover, horizontal heterogeneity, and sagebrush coverage. Percent cover of cac- tus was greater on grassland plots and was closely associated with several variables in- dicative of homogeneous single-layered stands. It is doubtful that lark sparrows avoided cactus, but rather they avoided habi- tats of which it was indicative. Lark sparrows occurred on 29 of the 38 study plots, and regression analysis of only these plots resulted in the same variables, order of entry, and nearly the same standardized coefficients. This would suggest that although the inter- pretation of the regression model may be somewhat confounded, the same two vari- ables were describing the observed use of habitats by lark sparrows. Brewer's sparrows were associated with dense areas of sagebrush within the study area and are considered sagebrush obligates October 1987 RuMBLE; Avian Habits 629 (Braun et al. 1976, Castrale 1982). Brewer's sparrows nest off the ground under the dense canopy of sagebrush (Best 1972), and in this study dense stands of sagebrush larger than 0.5 ha usually contained at least one singing male. Other shrub species such as Crateagus spp.. Primus spp., Amelanchier spp., Cean- othus velutinus, and Arctostophylos patula (Johnsguard and Rickard 1957, Beaver 1976) can provide the necessary habitat require- ments for Brewer's sparrows, thus demon- strating the importance of plant physiognomy rather than plant species to birds when com- pared across regions or habitat types. Best (1972) reported Brewer's sparrows nesting in dead sagebrush, substituting densely branched plants for the cover normally pro- vided by live foliage. Skunkbush sumac could presumably provide nesting cover at least comparable to sagebrush killed with herbi- cide. However, Brewer's sparrows were rare in the outcrop habitats, possibly because spac- ing between sumac plants was too great. A similar segregation of habitat selection was noted by Wiens and Rotenberry (1981) for Brewer's sparrows. Total avian density and species richness on study plots were both best modeled by posi- tive associations with attributes of the out- crops and negative associations with habitat features characteristic of the sagebrush/grass- land habitats on the study area. It was not possible to separate the effects of the shrubs and rocks in this study since the former were dependent, at least for establishment, on the latter (Biggins et al. 1985). Average height of the outcrops and volume of outcrops taller than 1.0 m were both positively correlated with abundance of sumac and currant (r > .70) on study plots. Taller and larger outcrops provide more protection from wind, greater snow accumulation on the lee side, greater surface area for runoff of rain, and a large mass to ameliorate the fluctuations in soil tempera- ture. Total herbaceous cover and percent cover of needle-and-thread grass were higher on the sagebrush/grassland study plots and were indicative of the homogeneous, single- layered stands. Thus, the negative correlation of these variables with total avian density and species richness was probably indicative of negative relationships between lack of struc- tural diversity and use of habitats by these bird species. Most small birds apparently distinguish habitats on the basis of structural characteris- tics (Cody 1985:7). Abundance of avian spe- cies in shrubsteppe habitats has been shown to be associated with increased vertical and horizontal diversity of the habitat (Rotenberry and Wiens 1980a). Even though the species diversity in sagebrush/grassland habitats was higher because of a more even distribution of individuals, species richness was higher and positively associated with the habitat pro- vided by the scoria outcrops and the immedi- ate plant community. Large differences in habitat structure result in unequal species abundance and possibly a decline in species diversity (Rotenberry 1978). Riceetal. (1980), Rotenberry and Wiens (1980b), and Wiens and Rotenberry (1981) suggested that species of vegetation were more important in deter- mining use of areas by avian species within habitat types. Within a habitat type, vegeta- tive structural characteristics are usually pro- vided by particular species. It was not possi- ble to separate the effects of individual shrub species from the added structural diversity in this study. Shrub species associated with the outcrop habitats are not typical shrubsteppe species, and the surrounding sagebrush/ grassland study plots did not provide similar structural diversity from which comparisons could be made between structural diversity and plant species. The results of this study indicate that at least to some extent the unique habitat provided by the scoria out- crops and the associated plant species re- sulted in increased species richness and total avian densities, and a different avian commu- nity during the breeding season compared with adjacent habitats. Management Recommendations Reclamation specialists may enhance wild- life habitats by placing suitable rocks on re- claimed mined land. While these habitats will be different from those originally on the site, it does not seem unreasonable to take advan- tage of opportunities to improve wildlife habi- tats in view of historic losses in many areas. Based on the results of this study, I recom- mend the following where rock piles are se- lected as a reclamation goal: (1) rock should be placed in piles of varying sizes up to 2 m in height; (2) rocks and rock piles should be 630 Great Basin Naturalist Vol. 47, No. 4 grouped, as opposed to evenly scattered, over large areas with approximately 9.0 rock piles per ha taller than 1.0 m; (3) the minimum area to include outcrop habitats should be about 1 ha; and (4) shrub species should be planted in and around piles to encourage establishment of unique plant communities (Biggins et al. 1985). Acknowledgments Appreciation is extended to Decker Coal Company, D. B. Johnson, M. R. Jackson, and D. E. Biggins for their cooperation and assis- tance during this study. R. Hodorff, J. Coons, and S. Denison assisted with data collection and analyses. L. B. Best, J. S. Castrale, D. M. Finch, K. Higgins, B. R. Noon, M. G. Raphael, and J. T. Rotenberry provided re- view of earlier drafts of this manuscript. Literature Cited Beaver, D L 1976. Avian populations in herbicide treated brush fields. Auk 93; 543-545. Best, L B 1972. First-year effects ofsagebrush control on two sparrows. J. Wildl. Manage. 36: 534-544. Biggins. D. E . D B Johnson, and M R Jackson 1985. Effects of rock structures and condensation traps on shrub establishment. Reclam. Reveg. Res. 4; 63-71. Braun. C E . M S. Baker. R L Eng. J S Gashwiler, AND M H SCHROEDER 1976. Conservation com- mittee report on: effects of alteration ofsagebrush communities on the associated avifauna. Wilson Bull. 88: 167-171. BuRNHAM, K P , D R Anderson, and J L Laake 1980. Estimation of density from line transect sampling of biological populations. Wildl. Monogr. No. 72. 202 pp. Castrale, J S 1982. Effects of two sagebrush control methods on nongame birds. J. Wildl. Manage. 46: 945-952. Cody, M. L 1985. Role of habitat selection in bird biol- ogy. Pages 4-56 in M. L. Cody, ed.. Habitat selection in birds. Academic Press, Inc., Orlando, Florida. 558 pp. Daubenmire.R D. 1959. A canopy cover method of vege- tational analysis. Northwest Sci. 33: 43-64. DixoN, W J , M J Brown, L Engleman, J W France, M A Hill, R 1 Jennrich, and J D Toporck 1983. BMDP statistical software. University of California Press, Berkeley. 733 pp. Evans, K E 1982. Proceedings of western mined-land rehabilitation research workshop. Nat. Tech. Infor. Serv,, Springfield, Virginia. 103 pp. JoHNSGUARD, P A , AND W H RiCKARD 1957. The rela- tion of spring bird distribution to a vegetation mosaic in southeastern Washington, Ecology 38: 171-174. Maser, C , J J Ceist, D. M Concannon, R Anderson, AND B Lovell 1979. Wildlife habitats in man- aged rangelands — the Great Basin of southeastern Oregon. Geomorphic and edaphic habitats. U.S. For. Serv. Pacific Northwest For. and Range E.xpt. Sta., Gen. Tech. Rept. PNW-99. 84 pp. Maser, C , J W Thomas, 1 D Luman, and R Anderson. 1979. Wildlife habitats in managed rangelands — the Great Basin of southeastern Oregon. Man- made habitats. U.S. For. Serv. Pacific Northwest For. and Range Expt. Sta., Gen, Tech, Rept. PNW-86. 39 pp. NiE, N H . C H Hull, J G Jenkins, K Steinbrenner, andD H Bent 1975, SPSS: statistical package for the social sciences. McGraw-Hill Book Co., Inc., New York. 675 pp. Payne, G F 1973, Vegetative rangeland types in Mon- tana. Mont. Agric. Expt. Sta. Bull. 671. Bozeman, Montana, 15 pp. PlELOU, E C 1975. Ecological diversity. John Wiley and Sons, Inc., New York, 165 pp. Renaud, W E 1979, The rock wren in Saskatchewan: status and distribution. Blue Jay 37: 138-148. Reynolds, R T , J M Scott, and R A Nassbaum 1980. A variable circular plot for estimating bird numbers. Condor 82: 309-313. Rice, J , B W Anderson, and R. D Ohmart 1980. Sea- sonal habitat selection by birds in the lower Colo- rado River Valley. Ecology 61: 1402-1411. Rotenberry, J T 1978. Components of avian diversity along a multifactorial climatic gradient. Ecology 59: 693-699. Rotenberry, J T , and J A Wiens 1980a. Habitat struc- ture, patchiness, and avian communities in North American steppe vegetation: a multivariate analy- sis. Ecology 61: 1228-1250. 1980b. Temporal variation in habitat structure and shrubsteppe bird dynamics. Oecologia47: 1-9. Roth, R R 1976. Spatial heterogeneity and bird species diversity. Ecology 57: 773-782. Steele, R D G , and J H Torrie 1960. Principles and procedures of statistics with special reference to biological sciences. McGraw-Hill Book Co., Inc., New York. 481 pp. Surface Mining Control and Reclamation Act 1977. Public Law 95-97, United States Statutes at Large. 95th Congress. Wiens, J. A, and J T Rotenberry 1981. Habitat associa- tions and community structure of birds in shrub- steppe environments. Ecol. Mono. 51: 21-41. COLORADO GROUND BEETLES (COLEOPTERA: CARABIDAE) FROM THE ROTGER COLLECTION, UNIVERSITY OF COLORADO MUSEUM Scott A. Elias' Abstract — Ground beetles from Rotger's collection of Colorado specimens have been identified, principally by the author, and a faunal list of 161 species from 80 localities is presented. The list includes 35 species not previously recorded from Colorado. Comparisons are made with Armin's (1963) carabid list from Boulder County and the diversity of species along transects through four elevational zones from the plains to the alpine. In 1986 the University of Colorado ac- quired an insect collection from the estate of the Reverend Bernard Rotger. Fr. Rotger, C.R., was a member of the order of Theatine Fathers of southern Colorado, and 19,000 specimens from his collection are now in the University of Colorado Museum. Rotger's col- lection of Coleoptera included 970 specimens of ground beetles (Carabidae) collected from sites in Colorado. Most of these specimens (88%) were unidentified when the museum obtained them. I have subsequently identi- fied these specimens, and I present here a list of all the carabid species from Rotger's Colo- rado collection at the University of Colorado museum (Table 1). This collection comprises 161 species from 80 collecting localities in 26 Colorado counties (Table 2). Most of the col- lecting localities are in the southern half of the state. The sites range in elevation from 1,100 m above sea level at Rocky Ford to 3,810 m in the Blanca Mountains. The Colorado carabid fauna is poorly known, in that the most recent published list of taxa is that of Wickham (1902). Armin's (1963) list covers only Boulder County, and Lindroth (1961-1969) gives only occasional mention of Colorado localities for various spe- cies. The list provided in Table 1 is the begin- ning of a modern list for the state, but it repre- sents only one collection, and that mostly of southern Colorado specimens. Methods The specimens were identified with the aid of Lindroth's (1961-1969) keys to the Cara- bidae of Canada and Alaska. Nearly all of Rot- ger's specimens were successfully identified through Lindroth's keys, but about 50 speci- mens did not appear to represent species treated by Lindroth. These specimens remain unidentified and are not cited in Table 1. Specimens o{ Elaphriis, identified by George Ball, were rechecked against Goulet's (1983) revision of that genus. Some of Rotger's original locality labels in- cluded site elevations, especially his high- mountain localities. Most other locality labels had no elevation data. Wherever possible, I have provided the elevations of these locali- ties as published in maps and gazetteers (Table 2). For some localities I could only provide rough estimates or ranges of possible elevations (e.g., localities cited from stream and river banks), and for a few localities I was unable to find any elevational citation from maps or from Gannett's (1906) state gazetteer. For the purposes of elevational zone group- ing, beetles collected below elevations of 2,000 m were designated as plains specimens. The foothills/lower montane zone was defined as greater than 2,000 m and less than 2,500 m. The subalpine zone was defined as greater than 2,500 m and less than 3,000 m. The alpine zone was defined as greater than 3,000 m. Discussion Table 1 lists 35 species not previouslv cited (i.e., Wickham 1902, Lindroth 1961-1969, Armin 1963) for Colorado. Some of these spe- cies may be more common in southern Colo- rado, a region which has received little prior Institute of .\rctic and .■\lpine Research, Box 450, University of Colorado, Boulder, Colorado 80309. 631 632 Great Basin Naturalist Vol. 47, No. 4 Table I. List of Carabidae identified from the Rotger Collection of Colorado specimens. Elevational range Species Collecting localities Dates Foothills/ collected Plains Lower montane Subalpine Alpine Scaphinotus elevatus Fabr. Carabus serratits Say' Carabus taedatus agassii LeC. Calosoma obsoletum Say Nebria arkansana Csy. Nebria gyUenhali Schonh.^- Nebria hudsonica LeC.^ Nebria metallica Fisch.* Nebria obliqua LeC.^ Nebria obtusa LeC.^ Nebria pallipes Say* Nebria purpurata LeC.^ Nebria trifaria LeC. Nebria trifaria catenata Csy.^ Opisthius richardsoni Kby.*' Notiophihis aquations L. Notiophihis semistriatus Say Notiophihis sinwlator Fall Elaphrus californicus Mannh. ' Elaphrus lecontei Crotch.^ Loricera pilicornis F. Pasimachus elongatus LeC. Pasimachus obsoletus LeC. Clivina impressifrons LeC* Patrobtis septentrionis Dej. Diplous aterrimus Dej. Trechiis apicalis Mots. * Trechus chahjbeus Dej. Trechus coloradensis Schaeff. Bembidion bifossidatum LeC. Bembidion cordatum LeC. Bembidion diligens Csy. * Bembidion grapei Gyll. Bembidion graphicum Csy. * Bembidion haruspex Csy. * Bembidion impotens Csy. Bembidion incrematum LeC* Bembidion levigatum Say* Bembidion mormon Hayw.* Bembidion nebraskense LeC. Bembidion obscurellum Mots. Bembidion patruele Dej.* Bembidion planiuscidiim Mannh. Bembidion rapidum LeC. Bembidion sordidum Kby. * Bembidion timidum LeC. Bembidion versicolor LeC. Tachijs anceps LeC. Tachys granarius Dej. * Pterostichus adstrictus Eschz. Pterostichus caudicalis Say Pterostichus chalcites Say* Pterostichus fattius Mannh.* Pterostichus femoralis Kby. Pterostichus leconteianus Ltsch. Pterostichus longulus LeC^ Pterostichus lucublandus Say 10 ? 48 VI 2,6,8-10,13,16,18, V/2-1X/6 + 30,33,34,54,60,63,79 31 VI 1 21,30,54,60 VI/7-VIII/21 3,33,63,69,76,79 V/21-VI1I/16 33,76 V/21-VI/13 53,79 V1/6-V11I/6 14 VI + 17 VI 1/4 53 Vlll/6 3,54,60,63 V1/18-V11/16 + 21,37,53 VI/6-VII1/21 21,60,76,77 V/21-VI11/21 14 VI/12 + 14,63 V/12-V1/13 + 75 Vll/26 57 lV/20 28,34,67 VI/8- VI/12 + 4 VI 24,36 V + 36,47,70 IV/29-IX/22 + 45,80 V/lO-VIlI/13 + 67 VI + 60 Vll 14,17,33,37,42,54,62, V/12-VIII/14 + 63,67,76 33 VI 13,51,79 V-IX/4 33,60,76 V/21-VI/13 24,36,71 V/3-VI1/1 + 36 V + 52,64 V1/7-IX/7 + 79 VI 4,24,36,60 V/3-V1 + 2,63,68,76 V/21-VII/13 71 X/1 + 71 X/1 + 73 X/4 + 24 V 24,52 V-IX 30 VII/1 20 IV 24 ? 72,73 X/l-X/4 + 52 IX/7 67,72 VI/13-X/1 + 52,67 V1/13-IX/7 + 64 Vl/7 + 11,52,73 IX/7-X/4 + 6,12,23,38,39,46,47,79 1V/19-X/30 + 48 V 66 VI/12 + 36 IV/12 + 36,38,79 111/29- Vl/16 + 26 IV/22 + 32 Vl/13 12 lV/21 + + + + + + October 1987 EliaS; Colorado Ground Beetles 633 Table 1 continued. Collecting Dates Elevational range Foothills/ Species localities collected Plains Lower montane Subalpine Alpine Pterostichus protractus LeC. 10,16,39,79 I\730-IX/1 + + Pterostichus scittilns LeC. 20,24,56 iv-ixy7 + + Pterostichus surg,ens LeC. 33,39,51,63,76,79 I\730-lX/4 + + Pterostichus torvus LeC. 7,40,43,72 iii/29-xyi + Calathusadvena LeC.^ 37,62,76,78 \720-VI/16 + + Calathus ingratus Dej.' 63 \T/18 + Calathus opaculus LeC. 40,75 III/29-VH + + Sijnuchus dubius LeC. 24 vni/6 + Agonum alceoncum Bates*^ 15,36 IV/3-\729 + Agonum californicum Dej. 22,24,39,67 v-vn/8 + + Agonum corvus LeC.^ 15,20 1V-V73 + Agonum cupreum Dej. 12 V/21 + Agonum cupripenne Say 15 V/3 ? Agonum extensicolle Say' 1,7,38,47,49 iii/29-\in + + Agon um ferruginosum Dej . ^ 15,33 V/3-V1/13 + Agonum subsericeum LeC. 24 V/12 + A7?!ara aeneopolita Csy.* 68 VI/2 + Amara alpina Pa\ k. 52,69 VII-IX/7 ? + A»iara carinata LeC. 38,56,71,72,73 III/29-X/4 + Amara coelebs Hayw. 68 VI/2 + Amarfl cf. confusa LeC. 68 VI/2 + A??iara coioe.va LeC. 12,67,74 IV/21-VI/27 + + Amara crassispina LeC* 12,36 IV/21-IV/29 + + Amora ellipsis Say* 78 V/20 ■? ? Amara erratica Dufts. 76 V/21 + Amara farcta LeC. 23,24,36,72 V/3-X/1 + + Amara idahoana Csy.* 63,68 VI/2-VI/13 + + A»iflra impuncticollis Say 4,12,56,67,78 IV/21-VII/10 4- + + Amara laevipennis Kby.* 20,74,76 IV-VI/27 + + A/riara latior Kl)y. 7,24,41,60,65,75 IX/30-X/10 + + + + Arnara lunicoUis Schiodte.* 12,74 IV/21-VI/27 + Amara oZjc.sa Say 24 VIII/6 + A/nara patruelis Dej. 68 VI/2 + Amara quenseli Schonnh. 63,68 VI/20-VII/11 + + Ainara sinuosa Csy. 68 VI/2 + A/riara thoracica Hayw. 10,11,13,23,24 V717-IX/19 + Cratacanthus dubius Beauv. 6.67 VI/ 12- VI 1/4 + + Piosoma setosum LeC. 65,74 VI/27-\TI/29 + + Euryderus grossiis Say 4,67,80 VII/7-VIII + + Harpalus amputatus Say 4,6,11,15,20.23,24,36. 56,65,72,79 IV/29-LV19 + + + Harpalus bicolor Fabr. 67 VI/12 + Harpalus caliginosus Fabr. 5,36,67 V/ll-VII/8 + Harpalus desertus LeC. 41,70 IV/30-IX/22 + Harpalus egregius Csy. 34 VI/8 + Harpalus erraticus Say 4 VII-IX + Harpalus fallax LeC. 24 V/17 + Harpalus faunus Say 5,24 VII/6 + Harpalus fraternus LeC. 6,9.29.35.56 V/26-IX/7 + + Harpalus fuliginosus Dufts. * 20,72,78 V/20-X/1 + + + Harpalus funerarius Csiki 56,67,70 VII/8-IXy22 + Harpalus herbivagus Say 50 V/19 + Harpalus lecontei Csy. 56 IX/7 + Harpalus opacipennis Hald. 1,6,12,20,24,36,58 IV-VII/30 + + + Harpalus paratus Csy. 4,56 VII-IX/7 + + Harpalus pleuriticus Kby. 24 V/17 + Harpalus seclusus Csy. 2,6,12,16,20,24,27,30, 37,50,56,63,72,78 IV/19-X/1 + + + + + Harpalus uteanus Csy. 12,20 I V/21 + Selenophorus pcdicularis Dej . 2,19,46,71 V/23-VII/20 + + + 634 Great Basin Naturalist Vol. 47, No. 4 Table 1 continued. Collecting Dates Elevational range Foothills/ Species localities collected Plains Lower montane Subalpine Alpine Selenophorus planipennis LeC . 24,36,39,47,74 IV/30-VI/27 + + + Discoderus parallelus Hald. 67,71 VI/13 + Anisodactylus harrisi LeC. 36,48,49 IV/27-V/3 + + Tricliocellus cognatus Gyll. 12 IV/21 + Bradycellus congener LeC. 11,24 V/17-IX/19 + Bradycellus leconetei Csiki 12 IV/21 + Stenolophiis anceps LeC. * 20 IV + Stenolophus comma F. 20,24,36,38,67 III/24-VI + + Stenolophiis conjunctus Say 6,36,49 IV/27-V/4 + + Stenolophus fuscatus Dej. * 24 V + Stenolophus rotundatus LeC* 16,40 III/29-IV + + Stenolophus rontundicollis 12,24 V/2I + Haldem.* Stenolophus unicolor Dej. 20,24 IV-V + Acupalpus indistinctus Dej.* 24,48,49 IV/27-V/17 + Dicaelus laevipennis LeC. 7 VIII + Badister neopidchellus Lth.* 20 IV + Chlaenius cordicollis Kby.* 64 VI/7 + Chlaenius leucoscelis Chevr. 7 VIII + Chlaenius nebraskensis LeC. 15,20,24 IV-V/3 + Chlaenius pensylvanicus Say 24 V + Chlaenius sericeus Forst. 1,48 V/6 + 4- Chlaenius tricolor Chd. 11,24 IX/19 + Lehia viridis Say 10,24 V/I7-IX/7 + Lebia vittata Fabr. 67 VI/13 + Apristus constrictus Csy. 64 VI/7 + Apristus pugetanus Csy. * 68 VI/2 + Microlestes linearis LeC. 52 IX/7 + Metabletus americanus Dej. 12,68 IV/21 -VI/2 + + Calleida viridis Dej. 24 VIII/6 + Cymindis americana Dej. 16,68 IV/19-VI/2 + + Cymindis horealis LeC. 11,52,70 IX/7-IX/22 + + Cymindis planipennis LeC. 52 IX/7 + Cymindis unicolor Kby. 27,60,68,80 VI/2-V1II/13 + + + Brachinus medius Harr. 36 V/3 + Specimens identified by Rotger, Specimens identified by David ICavanaugh, California Academy of Science Specimens identified by George Ball, University of Alberta *New published record for the state of Colorado. attention, whereas others may be widely dis- tributed in the state but simply not previously collected or identified for publication. Addi- tional statewide collecting may clarify this sit- uation for the species in question. Most species in the Rotger list appear to occur within the habitat range suggested by Lindroth (1961-1969) for specimens collected in Canada, Alaska, and elsewhere in North America. The most diverse carabid fauna was identified from the foothill and lower montane forest regions (45 species. Fig. IB). The plains zone produced 29 species, followed by the subalpine with 15 and the alpine zone with five species. Forty-six species were found in two zones, especially overlapping between the plains and foothills/lower montane zones (29 species). Seven species were found in three zones, and three species were found in all four zones. This distribution of species through four altitudinal zones contrasts with the distribu- tion of species through the same zones in Boulder County (Fig. lA), as described by Armin (1963). In Armin's study the plains zone contained the most diverse carabid fauna (61 species), followed by the foothills/mon- tane with 34 species, the subalpine with 21, and the alpine zone with only one species. Armin noted many species which occurred in two or more zones, but the patterns of zonal overlap are quite different from those in the October 1987 Elias; Colorado Ground Beetles 635 Table 2. List of collecting localities for specimens listed in Table L Site and elevation County 1. Brighton (1,520 m) 2. Blanca Mountains (3,660 m) 3. Blanca Mountains (3,810 m) 4. Great Sand Dunes Nat'l. Mon. (2,440 m) 5. Archuletta County (no specific site) 6. Archuletta Mesa (2,500 m) 7. Arboles (1,830 m) 8. Blanca Basin (2,560 m) 9. Near Blanco River at Hwy. 84 (2,380 m) 10. Burns Canyon near Trujillo (2,040 m) 11. Near Chromo (2,225 m) 12. Devil's Creek (ca 2, 130 m) 13. Devil's Mountain (2,740 m) 14. East Fork, San Juan River (ca 1,980 m) 15. Echo Lake 16. Eight Mile Fire Lookout (2,440 m) 17. Fish Creek (ca 2,900 m) 18. Four Mile Creek (ca 1,980 m) 19. Frances Martinez Creek (ca 2, 130 m) 20. LakePagosa(2,160m) 21. Little Sand Creek (ca 2,590 m) 22. Pagosa Junction (1,910 m) 23. Pagosa Springs (2, 160 m) 24. Stevens Reservoir (2,320 m) 25. Rio Conejos C2 26. Boulder (1,660 m) 27. Rio Conejos (ca 2,440 m) 28. Rio San Antonio near Manassa (2,350 m) 29. Blanca (2,360 m) 30. Forbes Road (2,590 m) 31. West of Jaroso (2,310 m) 32. La Veta Pass (2,870 m) 33. Pass Creek near La Veta Pass (ca 2,800 m) 34. Rito Seco (ca 2,590 m) 35. San Luis (2,430 m) 36. Denver (1,610 m) 37. Vicinity of Ophir (2,830 m) 38. Near Denver (1,610 m) 39. Devil's Head Mountain (ca 2,740 m) 40. Near Franktown (1,870 m) 41. Near Sedalia (1,800 m) 42. Weminuche Pass (3,240 m) 43. Hwy. 10 at Cucharas River (1,890 m) 44. Huerfano (1,730 m) 45. Near Tioga (ca 1,730 m) 46. Golden (1,730 m) 47. Morrison (2,410 m) 48. Near Morrison (ca 2,410 m) 49. One mile W of Morrison (ca 2,560 m) 50. East of Jefferson County 51. Cold Water Creek (ca 2,870 m) 52. Hersperus (2,470 m) 53. La Plata Creek (ca 3,200 m) 54. La Plata Mountains (ca 3,200 m) 55. La Plata Mountains (3,200 m) 56. La Posta (1,920 m) 57. Vallecitos (2,340 m) 58. Rist Canyon 59. Pass Creek (ca 3,200 m) 60. Wolf Creek Pass (3,200 m) 61. Wolf Creek Pass (3,310 m) 62. Wolf Creek Pass (3,320 m) Adams Alamosa Alamosa Alamosa/Saguache Archuletta Archuletta Archuletta Archuletta Archuletta Archuletta Archuletta Archuletta Archuletta Archuletta Archuletta Archuletta Archuletta Archuletta Archuletta Archuletta Archuletta Archuletta Archuletta Archuletta Archuletta Boulder Conejos Conejos Costilla Costilla Costilla Costilla Costilla Costilla Costilla Denver Dolores Douglas Douglas Douglas Douglas Hinsdale Huerfano Huerfano Huerfano Jefferson Jefferson Jefferson Jefferson ? La Plata La Plata La Plata La Plata La Plata La Plata La Plata Larimer Mineral Mineral Mineral Mineral 636 Great Basin Naturalist Vol. 47, No. 4 Table 2 continued. Site and elevation County 63. Wolf Creek Pass (3,410 m) 64. Four Corners (ca 1,520 m) 65. Paradox (1,610 m) 66. La Junta (1,240 m) 67. Rocky Ford (1,270 m) 68. Park County (no specific locality) 69. Mount Evans (3,810 m) 70. 16 miles SofLamar (1,100 m) 71. Pueblo (1,430 m) 72. 10 miles E of Pueblo (1,420 m) 73. St. Charles River (ca 1,430 m) 74. Del Norte (2,400 m) 75. Elwood Pass (3,350 m) 76. Copper Gulch (ca 2,830 m) 77. Cunningham Gulch (ca 2,740 m) 78. Placer Gulch 79. Vicinity of Ophir (2,830 m) 80. Roggen (1,430 m) Mineral Montezuma Montrose Otero Otero Park Park Prowers Pueblo Pueblo Pueblo Rio Grande Rio Grande San Juan San Juan San Juan San Miguel Weld Rotger faunal list. Armin found only 16 spe- cies living both on the plains and in the foothills/montane zones, and a broader over- lap of species between the montane and sub- alpine zones than was found in the Rotger list. Also, Armin identified 18 species living throughout four zones, compared with only three species in the Rotger list. It may be that these differences in faunal diversity along alti- tudinal transects represent real differences between the carabid faunas of southern and northern Colorado. On the other hand, Armin's habitat preference data may be more reliable than that derived from the Rotger list because Armin systematically collected along altitudinal transects in Boulder County through four field seasons, identifying a col- lection of more than 5,000 specimens, whereas Rotger's collecting appears to have been much more sporadic, with no apparent effort to collect specimens along altitudinal transects. Hence, some elevational ranges and types of habitats are poorly represented in Rotger's collection. Again, additional collect- ing must be done if we are to fully understand the ecological requirements and distributions of the Colorado carabid fauna. Acknowledgments I thank Dr. U. N. Lanham, Curator of En- tomology at the University of Colorado Mu- seum, for permission to study Rotger's cara- bid specimens. Dr. George Ball, University of Alberta, provided useful suggestions for the preparation of the manuscript and identified several species. Financial support for manuscript preparation was provided by an NSF Grant, DPP 8619310. Literature Cited Armin, L. C. 1963. A study of the family Carabidae (Cole- optera) in Boulder County, Colorado. Unpub- lished dissertation, University of Colorado, Boul- der. 465 pp. Gannett, H. 1906. A gazetteer of Colorado. U.S. Geolog- ical Survey Bulletin 291. 185 pp. GouLET, H. 1983. The genera of holarctic Elaphrini and species of Elaphrtis Fabricius (Coleoptera; Cara- bidae): classification, phylogeny, and zoogeogra- phy. Quaestiones Entomologicae 19: 219-482. LiNDROTH, C. H. 1961. The ground beetles of Canada and Alaska, part 2. Opuscula Entomologica Suppl. 20: 1-200. 1963. The ground beetles of Canada and Alaska, part 3. Opuscula Entomologica Suppl. 24; 201- 408. 1966. The ground beetles of Canada and Alaska, part 4. Opuscula Entomologica Suppl. 29: 409- 648. 1968. The ground beetles of Canada and Alaska, part 5. Opuscula Entomologica Suppl. 33: 649- 944. 1969a. The ground beetles of Canada and Alaska, part 6. Opuscula Entomologica Suppl. 34: 945- 1192. 1969b. The ground beetles of Canada and Alaska, part 1. Opuscula Entomologica Suppl. 35: i-xlviii. WiCKHAM, H F 1902. A catalogue of the Coleoptera of Colorado. Bulletin of the Laboratories of Natural Historv of the State of Iowa 5: 217-309. October 1987 A 20 Elias: Colorado Ground Beetles Foothills/Montane 637 Subalpine Alpine 60 80 Number of Species 100 B Foothills/Montane A Alpine Subalpine a 60 80 Number of Species Fig. L Number of identified carabid species found in four elevational zones: (A) Armin (1963) in Boulder County, (B) the Rotger collection of Colorado specimens. Cross-hatched zones indicate species that overlap adjacent elevational zones. Species occupying three or more zones are excluded from the figure. WINTER HABITAT-USE PATTERNS OF ELK, MULE DEER, AND MOOSE IN SOUTHWESTERN WYOMING Olin O. Oedekoven'^and Fredrick G. Lindzey' Abstract. — Habitat-use patterns of mule deer, elk, and moose were determined on two winter ranges near Kemmerer, Wyoming. Mule deer used areas with the least snow depth and dominated by sagebrush. Elk were located more often than expected on wind-swept hills but used sagebrush communities more frequently as snow depths increased. Moose were generally found associated with broad, riparian zones. All three species occasionally used the same area but differed in their use of specific vegetation types and topography. Many winter ranges in the Rocky Moun- tains are used by two big game species, but few ranges support three or more species of large ungulates. Nelson (1981) suggested that although mule deer (Odocoileus hemionus) and elk (Cervis elaphus) often share winter ranges, these species compete for forage only during extreme environmental conditions. His conclusions were based on the differing foraging strategies of mule deer and elk; elk selected mostly grasses, while mule deer pre- ferred browse species. Elk and moose {Alces alces) relationships on winter ranges were evaluated by Stevens (1974), Nelson (1981), and Rounds (1981). These authors concluded that because elk and moose occupied unique habitats and exhibited differing diets, they were not usually competitors. Moose and elk appear to fill two discrete ecological niches with respect to range, food habitats, physical characteristics, and social organization. The purpose of this study was to document the winter distribution of three ungulate spe- cies on two adjacent winter ranges and to identify habitat characteristics associated with the distribution of each species. Study Areas The study included a majority of two large, adjacent big game winter range complexes in southwestern Wyoming (Wyoming Game and Fish Department, unpublished files 1983). The two winter ranges are separated by high- elevation mountains (3,500 m) that receive little or no use by ungulates during midwin- ter. The combined 1985 population estimates for these areas were 20,000 mule deer, 2,700 elk, and 1,000 moose (Wyoming Game and Fish Department, unpublished files 1985). The western wintering area is about 15 km wide by 32 km long, and the eastern area is 28 by 46 km. Drainages generally flow from the north to south and east to west within the western area and west to east within the east- ern area. Western exposures dominate the western portion and eastern exposures the eastern area. Elevations vary from 2,800 m to 1,800 m. Annual precipitation ranges from 25 to 35 cm, gradually shifting to less than 25 cm in the more xeric eastern portions of the win- ter range. Average growing season is 60-90 days (Bureau of Land Management, Kem- merer Resource Area, unpublished files). Sagebrush {Artemisia spp.) rangeland (Lanka et al. 1983) characterizes the majority of both winter ranges. This shrub vegetation type is composed of big sagebrush (A. triden- tata), with lesser amounts of black sagebrush (A. nova), saltbushes {Atriplex spp.), and black greasewood {Sarcobatus vermiculatus). Mixed-shrub communities are found on more mesic sites. This community is dominated by Utah serviceberry {Aynelanchier utahensis), western snowberry {Symphoricarpos occi- dentalis), and antelope bitterbrush {Pursha tridentata). Quaking aspen {Populus tremu- loides)sLre present in small (< 0.5 ha) stands at higher elevations. Willow (Salix spp.) and grass meadows dominate the larger river bot- toms. Pockets of mixed conifers dominated by Engelmann spruce {Picea engehnannii) and University of Wyoming Cooperative Fish and Wildlife Research Unit, Box 3166 University Station, Laramie, Wyoming 82071. ^Present address: Wyoming Game and Fish Department, 2800 Pheasant Drive, Casper, Wyoming 82604. 638 October 1987 Oedekoven, Lindzey: Winter Habitat in Wyoming 639 subalpine fir {Abies hisiocarpa) are common on the steep, usually northern exposures of the higher-elevation ridgelines. An extensive stand of curl-leaf mountain mahogany {Cerco- carpus ledifolius) is present on the northwest- ern portion of the western winter range. Ju- niper (Juniperus spp.) stands are infrequent and limited to small (< 0.25 ha) pockets. Higher ridges that are devoid of shrubs are generally vegetated by mosses, lichens, and warm-season grasses (Poaceae). Most of the land in both winter ranges is administered by the Bureau of Land Manage- ment or the State of Wyoming. Principle land uses include grazing by cattle and domestic sheep and energy exploration and extraction. Methods Aerial Surveys Flights w^ere conducted over the winter ranges during December and January of each year. A highly modified Maule N5AR single- engine, fixed-wing aircraft (Stockhill 1986) was used to fly 0.9-km-wide, established tran- sects. Transects were located to provide com- plete and consistent coverage of the winter range. Animal locations were recorded on an onboard computer interfaced with an area navigational system. Locations were recorded in precise latitude and longitude coordinates as the aircraft flew over each animal group (one or more animals). This navigational sys- tem also allowed the same predetermined transects to be flown each month. Data Collection Vegetation type, topography, exposure, snow depth, snow cover, and animal activity were recorded for each observation. Vegeta- tion-type categories included sage-grass, mixed shrub, aspen, willow, mountain ma- hogany, mixed conifer, alpine grass, and agri- cultural areas. Topographic categories were: drainage (draws, ditches, and narrow canyons), flat (less than 5% slope), toeslope (slope base to 30 m up a slope), steep (20-h% slope), ridgeline, and hilltop. Exposure cate- gories were one of the eight cardinal direc- tions. Snow conditions were estimated for the area occupied by an animal group and in- cluded snow depth and percent snow cover. Estimates of snow depth were subjective and based on height of plants and animals. Estimates of availability of the various vege- tative communities, topographic, and snow- condition categories were obtained by making observations at intervals of three nautical miles during aerial surveys. Data were recorded for the availability site (about 50 x 50 m) in the same manner as that used when animals were observed. Characteristics of sites where animals were observed were com- pared to estimates of availability using Chi- square tests of independence (Khazanie 1979) with the Mine Tab computer program (Ryan et al. 1985). Spatial overlap of species was examined by simply comparing counts of spe- cies present in 1.6-km" grids. These grids were positioned on section, range, and town- ship boundaries. Evaluation of Potential Sampling Biases Making inferences from observation data about dispersion or habitat-use patterns re- quires that several assumptions regarding ani- mal detectability be met. Animals should be equally or proportionately detectable throughout the sampled area (species and in- dividuals). To evaluate the possibility that deer, elk, and moose were more easily de- tected from the airplane when standing or bedded or in specific vegetation types, we conducted surveys on the ground after each flight. We located animals by searching with a truck or snowmobile or driving to areas where they had been observed from the airplane. Once we located an animal or group of ani- mals, we visited them periodically through the day and noted the activity (standing or bedded) and habitat type for each animal. Ob- servations were not begun for at least 0.5 hr after the group was first located to minimize the possibility that they were located because of their activity or the vegetation type in which they were initially found. Results of ground surveys were compared with results of the airplane transects to identify differences that would suggest differential detectability. Additionally, we searched areas on the ground for animals and their sign where no animal had been observed from the air. On five occasions we walked or drove through dense vegetation types (i.e., sagebrush draws, mountain brush stands) and attempted to count the animals present for comparison with counts made from the air. 640 Great Basin Naturalist Vol. 47, No. 4 Table 1. Mule deer, elk, and moose observed during aerial transects and ground surveys in southwestern Wyoming, 1984-1986. Aerial transects Ground surveys 1984-85 1985-86 1984-85 1985-86 Mule deer Elk Moose 188(2131)' 90 (2455) 98 (207) 172 (3025) 121 (2806) 96 (244) 111(1325) 48(1157) 15 (28) 150(1486) 37 (1563) 18 (26) 'Number of individuals observed. Table 2. Percent of mule deer, elk, and moose observations in the various vegetation categories during the winters of 1984-85 and 1985-86 and estimates of availability as determined from monthly aerial sampling. Mule deer Elk Moose Availability Vegetation 1984-85 1985-86 1984-85 1985-86 1984-85 1985-86 (n = 188) (n=172) (n = 90) (n = 121) (n = 98) (n = 96) (n = 724) Sage-grass 89" 100' 73 48" 29" 9" 77 Mixed shrub 8 — 7 16" 14" 14" 8 Aspen — — 8" 2 23" 6 3 Willow riparian — — 1 6 28" 64" 4 Agriculture — — — 1 — 1 1 Alpine grass/moss — — 8" 26" — — 2 Mountain mahogany 1 — 1 1 5" 5" 1 Conifer — — — — 1 1 3 Juniper 2 — 2 — — — 1 "Significant (p < . 10) differences between proportionate use and availability. Results Observations Transects were flown during December and January of the 1984-85 and 1985-86 win- ters. Ground surveys were conducted follow- ing flights on 33 days over the two winters (Table 1). Numbers of observations are pre- sented in Table 1. Sampling Biases Surveys of areas where no animals were seen from the plane indicated that few animals were not detected from the air. During five extensive searches, no animals were seen and little sign was found. The proportion of ani- mals observed standing during two-hour day- light periods in ground and aerial surveys did not diffier significantly, suggesting that animal activity did not influence detectability from the airplane (mule deer, x" = 6.7, p > .10, 5 df; elk, x^ = 4.3, p > . 10, 5 df, moose, x' = 3.9, p>.10, 5df) Vegetation-use patterns identified from the air did not differ significantly from those iden- tified from ground surveys for either elk (x" = 7.6, p > . 10, 6 df) or moose (x" = 4.8, p > . 10, 6 df), but slightly significant differences were found between the two samples for mule deer (x^ = 1.37, p < .10, 6 df). Greater use of the mixed-shrub vegetation type was observed during ground surveys, suggesting that mule deer use of mixed-shrub vegetation was slightly underestimated from the air. No sig- nificant difference (p < . 10) was detected be- tween the ground and airplane samples for any of the species in the use of topography, exposures, or snow-conditions classes. Habitat Use The following analyses are based only on observations from the airplane. Results sug- gested that deer, elk, and moose selected specific vegetation (Table 2), topography (Table 3), exposure (Table 4), and snow-condi- tions (Table 5) categories. Mule deer used sagebrush vegetation extensively both win- ters. Conversely, moose favored aspen, wil- low, and mixed-shrub vegetation over the proportionally more abundant sagebrush veg- etation (Table 2). Elk used the alpine grass/ moss vegetation type more than expected on the basis of availability of this type (Table 1). Mule deer typically favored drainage, flat, and ridgeline topography, and elk were most frequently observed in more irregular terrain including ridges, hilltops, and steep topogra- phy (Table 3). Although some moose were October 1987 Oedekoven, Lindzey; Winter Habitat in Wyoming 641 Table 3. Percent of mule deer, elk, and moose observations in the various topographic categories during the winters of 1984-85 and 1985-86 and estimates of availahihty as determined from monthly aerial sampling. Mule deer Elk Moose Availability Topography 1984-85 1985-86 1984-85 1985-86 1984-85 1985-86 (n = 188) (n=172) (n = 90) (n-121) (n = 98) (n = 96) (n = 724) Drainage 28- 16' 14 2" 42" 11 10 Flat 29" 23" 26" 18" 23" 63" 36 Toeslope 5 8 2 1" — = 3 6 Gentle 12^ 16" 14" 13^ 25 5^ 25 Steep 6' 16 12 18" 6" 14 12 Ridgeline ir 12" 21" 17" 2 3 4 Hilltop 6 9 11 31" 2" 1" 7 •■Significant (p < . 10) differences between proportionate use and availability. T.\BLE 4. Percent of mule deer, elk, and moose observations in the various exposure categories during the winters of 1984-85 and 1985-86 and estimates of availability as determined from monthly aerial sampling. Mule deer Elk Moose Availability Exposure 1984-85 1985-86 1984-85 1985- 86 1984-85 1985-86 (n = 188) (n=172) (n = 90) (n=12 ;i) (n = 98) (n = 96) (n = 724) North 12 7" 3" 16 9 21 15 Northeast 3 8" 2 5 12" 15" 4 East 12" 2" 10" 23" 12" 6" 32 Southeast 5 — " 6 6 6 4 South 22 70" 15" 11" 2" 9" 24 Southwest 14" 1 34" 6 6 — 4 West 27" 6" 30" 5" 45" 49" 15 Northwest 5" 6" — 28" 8" — 2 "Significant (p < . 10) differences between proportionate use and availability observed in upland habitats, most were found within the broad, flat, willow riparian bottoms of the more extensive riverine systems. Mule deer were most frequently observed on southern and western exposures and tended to avoid the shaded, northern e.xpo- sures (Table 4). Elk occupied a variety of expo- sures but tended to avoid eastern and south- ern exposures. Mule deer and elk selected areas with mild snow conditions, while moose were com- monly found in areas with deep snow and nearly 100% snow cover (Table 5). Spatial Overlap Less than 30% of the combined winter ranges was used by the three species either winter, but many areas were used by more than one species (Table 6). The greatest amount of interspecific overlap occurred dur- ing January of the first winter and December of the second winter. Occasionally, all three species were found in the same grid (1-2%). Although two species often occupied the same grid, their use of habitats within the grids differed. Significant (p < . 10) differ- ences were found among the use patterns of each major habitat category (vegetation, x" = 2.76; topography, x~ = 13.3; exposure, x^ = 127.7). Discussion Sampling Evaluation The similarity of results of ground and aerial surveys does not necessarily preclude the presence of bias in the aerial sample. Differ- ential detectability is potentially a problem in both survey methods, and thus the results of both may be similarly biased. Dense vegeta- tion is a major factor influencing detectability (Springer 1950, LaRouche and Rausch 1974), however, and the occupied wintering areas we surveyed had little dense vegetation. Ju- niper woodlands were very uncommon, and conifer forests were generally at higher eleva- tions and accompanied by deep snow that pre- cluded much use by ungulates. The three spe- cies appeared equally detectable over the occupied wintering areas. The single excep- tion was the reduced detectabilitv of mule 642 Great Basin Naturalist Vol. 47, No. 4 Table 5. Percent of mule deer, elk, and moose observations in the various snow-condition categories during the winters of 1984-85 and 1985-86 and estimates of availability as determined from monthly aerial sampling. Mule deer Elk Moose Availability Percent snow 1984-85 1985-86 1984-85 1985-86 1984-85 1985-86 1984-85 1985-86 cover (n = 188) (n=172) (n = 90) (n = 121) (n = 98) (n = 96) (n=124) (n = 293) Bare — T — 13" — — — 2 1-25 2 1 — 1 — — — 2 26-50 T 3 — 13" — — 1 1 51-75 34" 17" 14" 5 — 2" 3 4 76-100 57" 72" 86" 68" 100" 98" 96 91 Average snow depth 0-15 cm 64" 52" 58 54" 31" 3" 51 22 16-30 cm 36 48 39 39" 64" 64" 34 50 31-45 cm — — 3" 6" 5" 30" 13 20 45-60 cm — — — 1" — 3 2 8 'Significant (p < 10) differences between proportionate use and availability. Table 6. Animal use of 1.6-km^ grids species during the winters of 1984-85 and 1985- 1984-85 1985-86 Dec. Jan. Dec. Jan. Number of available grids 480 480 480 480 Number of occupied grids 127 137" 125 105 Percent of use by at least one species 26 29 26 22 Percent occupied by two species 10"'' 19" 2pb 16" Mule deer-elk gab 8" 11'' 8 Elk-moose 4 7 6 5 Mule deer-moose 3 4 4 4 Percent occupied by three species 2 1 2 2 "Significant (p < . 10) difference between months in same winter Significant (p < . 10) difference between month in two winters. deer from the air when they were in mixed- shrub habitat. Habitat Use Mule deer, the smallest of the three spe- cies, tended to use sagebrush habitats at lower elevations in areas with the least snow cover. This pattern undoubtedly reflects the influ- ence of snow conditions and diet. Gilbert et al. (1970) reported that mule deer were gener- ally restricted to habitats with less than 50 cm of snow. Winter diets of mule deer are domi- nated by browse species including big sage- brush and antelope bitterbrush (Smith 1952, Wilkins 1957). Elk generally occupied wind-swept ridges and hilltops vegetated by alpine grasses and moss; they moved into lower, shrub-domi- nated habitats only when snow cover and depth increased. Nelson and Leege (1981) re- ported that elk winter diets were strongly in- fluenced by forage availability as dictated by snow conditions. Elk tended to select grasses and shift to a browse diet only when grass resources became unavailable because of deep snow cover. Beall (1974) found that elk generally foraged along the upper portions of steeper slopes where solar radiation and wind acted to reduce snow cover. Moose appear the least influenced of the three species by deep snow because of their powerful build and large hoof size (Kelsall 1969, Coady 1974). Winter diets of moose are largely governed by the available vegetation, but, overall, moose prefer browse species such as willow, rose {Rosa spp.), and occasion- ally conifers (Peek 1974). Our results indi- cated that moose selected willow riparian habitats. When moose occupied the more up- land sites, however, they tended to select conifer, aspen, and mixed-shrub vegetation types associated with steep, northern expo- sures with deeper snow cover. Snow cover on northern exposures tended to be more pow- October 1987 Oedekoven, Lindzey: Winter Habitat in Wyoming 643 dery, allowing fairly unrestricted movement by moose. Our results suggested that although deer, elk, and moose often used the same areas, they selected differing habitats within shared areas. These patterns might be expected to change with deeper snow as suggested by CliflF (1939). The greatest spatial overlap of elk and mule deer occurred during January of the first winter and December of the second, the months with the greatest snow depths (Table 2). Because of the dominant use and availabil- ity of the sagebrush vegetation type, slightly underestimating deer use of mixed-shrub vegetation from the airplane would not demonstrably alter the results presented. Acknowledgments We would like to express our gratitude for the cooperative efforts of the Wyoming Game and Fish Department, the Bureau of Land Management, and the University of Wyo- ming. E. Raper was instrumental in the suc- cess of the project. Funding for the project was provided by the Wyoming Game and Fish Department, and it was conducted under the auspices of the Wyoming Cooperative Fish- ery and Wildlife Research Unit. Literature Cited Beall, R C 1974. Winter habitat selection and use by a western Montana elk herd. Unpubhshed disserta- tion, University of Montana, Missoula. 197 pp. Cliff, E P 1939. Relationship between elk and mule deer in the Blue Mountains of Oregon. Trans. N. Amer. Wildl. Conf. 4: 560-,569. COADY. J W. 1974. Influence of snow on behavior of moose. Nat. Canadienne 101: 417-436. Gilbert, P F , O C Wallmo, and R B Gill 1970. Ef- fect of snow depth on mule deer in Middle Park, Colorado. J. Wildl. Manage. .34(1); 15-23. Kelsall, J P 1969. Structural adaptations of moose and deer for snow. J. Mammal. 50(2): 302-310. Khazanie, R 1979. Elementary statistics in a world of applications. Good Year Publ. Co., Santa Monica, California. 488 pp. Lanka, R P , D B. Inkley, and S H Anderson 1983. Wyoming and Montana land cover classification and mapping project. Final Rept., U.S. Dept. Inter., Fish and Wildl. Serv., Wyoming Fish and Wildl. Coop. Res. Unit, Laramie. 33 pp., 2 maps. LeResche, R E , and R A Rausch. 1974. Accuracy and precision of aerial moose censusing. J. Wildl. Manage. 38(2): 175-182. Nelson, J R 1981. Relationships of elk and other large herbivores. Pages 415-441 in J. W. Thomas and D. E. Toweill, eds.. Elk of North America: ecol- ogy and management. Stackpole Books, Harris- burg, Pennsylvania. 698 pp. Nelson,] R.andT A Leege, 1981. Nutritional require- ments and food habits. Pages 323-367 in J. W. Thomas and D. E. Toweill, eds.. Elk of North America: ecology and management. Stackpole Books, Harrisburg, Pennsylvania. 698 pp. Peek, J M 1974. On the nature of winter habitats of Shiras moose. Nat. Canadienne 101: 131-141. Rounds, R. C 1981. First approximation of habitat selec- tivity of ungulates on extensive winter ranges. J. Wildl. Manage. 45(1): 187-196. Ryan, B F , B L Joiner, andT A Ryan, Jr 1985. Minitab handbook. Sec. Rd. Dusbury Press, Boston. 374 pp. Smith, J, G 1952. Food habits of mule deer in Utah. J. Wildl. Manage. 16(2): 148-155. Springer, L. M 1950. Aerial census of interstate antelope herds of California, Idaho, Nevada, and Oregon. J. Wildl. Manage. 14(3): 295-298. Stevens, D. R 1974. Rocky Mountain elk-Shiras moose range relationships. Nat. Canadienne 101(4): 505-516. Stockhill, M E 1986. The making of a microchip Maule. Aero (10): 18-25. Wilkins, B T 19.57. Range use, food habits, and agricul- tural relationships of the mule deer, Bridger Mountains, Montana. J. Wildl. Manage. 21(2): 1,59-169. HERBIVOROUS AND PARASITIC INSECT GUILDS ASSOCIATED WITH GREAT BASIN WILDRYE {ELYMUS CINEREUS) IN SOUTHERN IDAHO' Berta A. Youtie", Michael Stafford", and James B. Johnson Abstract — Insects inhabiting Great Basin wildrye {Elymiis cinereus Scribn. & Merr.) were surveyed at two sites on the Snake River Plain in southern Idaho during 1982 and 1983. Forty-six species of phytophagous insects were observed. In addition, eight parasitoid species were reared from insect hosts in the plant culms and identified. Life stage, abundance, plant part utilized, and study site were recorded for each insect species collected. Insect guilds at the two sites were compared based on species presence utilizing Sorensen's similarity index. Overall, 26 insect species were common to both sites, yielding a moderate similarity index of 0.62. The majority of the species that constitute the wildrye herbivore guilds were oligophagous (restricted to grasses). Many of these insects feed on grain crops as well as other native and introduced grasses. The relatively high diversity of phytophages on wildrye mav be due to its tall, bunchgrass growth form, its abundance within its habitat, its broad geographic range, and the large number of related species of grasses in the region. Great Basin wildrye {Elymus cinereus Scribn. & Merr.) is one of the largest and most widespread native bunchgrasses in the west- ern U.S. (Lesperance et al. 1978). It is an important component of both the salt desert shrub and sagebrush/grass ecosystems. Every spring and summer the plant produces enor- mous amounts of biomass that may be ex- ploited by vertebrate and invertebrate herbi- vores. Much is known of wiklrye's palatability and utilization by large ungulate grazers (Perry and Chapman 1974, 1975, Krall et al. 1971, Lesperance et al. 1978, Murray et al. 1978), but there has been no comprehensive study of its phytophagous insect communi- ties. An attempt was made to partition the plant into anatomical regions and identify the associated insect herbivore guilds and their parasitoids. The impacts and diversity of these guilds are discussed. Methods Insects associated with Great Basin wildrye were surveyed at two sites on the Idaho Snake River Plain during 1982 and 1983. The 1. 1-ha, lower-elevation (1,475 m), and drier (246 mm precipitation/yr) site was located on the Idaho National Engineering Laboratory (INEL), 10 km south of Howe, Butte Co. Wildrye occu- pied low, saline areas surrounded by higher ground that supported Wyoming big sage- brush {Artemisia tridentata subsp. wyomin- gensis Beetle). The second site was located in the north end of Craters of the Moon National Monument (CRMO), 29 km southwest of Arco at 1,817 m elevation. The precipitation is al- most twice as abundant at this site (426 mm/ yr). Wildrye grew on an 8.5-ha, relatively wet meadow that was surrounded by mountain big sagebrush {Arte7nisia tridentata subsp. vaseyana [Ryberg] Beetle). Insects were monitored on the host plant from its three-leaf phenological stage in May through seed maturation in late August. Fif- teen plants were randomly selected along two random, 50-m transects at each site at weekly intervals. The insect fauna on each host plant was observed for five minutes. Insect life stage, behavior, relative abundance, and plant parts utilized were recorded. Insects were hand-picked or aspirated from the grass for later identification. Presence of internal feeders was determined by dissecting five tillers from each plant. Each week five plants at each site were excavated, examined for root- and root-crown-infesting insects, and placed into Berlese funnels to collect the resi- dent insects. Insect feeding was determined by direct observation such as mouthpart insertion and plant damage. While not absolutely definitive in all cases, this method is more accurate than previous sweep-net sampling programs 'Published with the approval of the director of the Idaho Agricultural Experiment Station as Research Paper No. 87714. ^Department of Plant, Soil and Entomological Sciences, University of Idaho. Moscow, Idaho 8.3843. 644 October 1987 YOUTIE ETAL.: WiLDRVE INSECTS IN IDAHO 645 (Horning and Barr 1968). Results and Discussion Forty-six insect species in 22 families and seven orders were identified as feeding on wildrye. Each species was categorized as to abundance, life-stage feeding on wildrye, re- gion of the host plant utilized, and host specificity (Table 1). Eight species of para- sitoids were also reared from insect hosts in the culms and identified (Table 2). The host plant was partitioned into five anatomical components: roots, culms, leaves, flowers, and seeds. Each region supported a variety of insect species that employed different feeding strategies. Many of the insects utilized more than one plant part and thus were identified in more than one guild. Root-Feeders Aphids, mealybugs, and beetle larvae were the most abundant insects feeding on wildrye roots. The aphids, Forda marginata and F. olivacea, were collected in low numbers in the spring and early summer. Both species have been reported to feed only on grass roots and are associated with ant nests (Gillette 1918, Patch 1939, Gittins et al. 1976, Smith and Parron 1978). Two pseudococcids were less frequently collected on the roots of the host plant. One, Crijptoripersia trichura, is known to inhabit grass roots in Arizona and New Mexico (MacGillivray 1921). Elaterid larvae, wireworms, were very common in the soil surrounding the roots and are known as major pests of grains and range grasses. Chafer larvae, Dichelonyx sp., and adult weevils, Brachyrhinus ovatus, were found to infest Great Basin wildrye roots at CRMO. Adult billbugs, Sphenophorous gen- tilis, were very common on the seed heads of E. cinereus at INEL. Billbug larvae are known to feed on the roots of a variety of grasses (Asay et al. 1983, Tashiro and Person- ius 1970, Kamm 1969) and were believed to feed on the roots of wildrye at the study site, but could not be located. Cerambycid larvae were collected in the root masses of wildrye and identified to the subfamily Lepturinae. Cortodera barri, a cerambycid commonly ob- served feeding on wildrye pollen as an adult, was the only species belonging to this subfam- ily found in the area. Therefore, it seems likely that the larvae belonged to this species. Culm- and Leaf-Feeders A large number of herbivores utilize both the culms and leaves of grasses; therefore, these two anatomical regions are discussed together. Grasshoppers are one of the most common and destructive groups of insects on western ranges (Watts et al. 1982). They are the most visible pests and have been studied more than any other graminivorous insects. Five species of acridids were collected on wildrye during the summers of 1982 and 1983. Four of these species are in the genus Melanoplus, with the migratory grasshopper, M. sangtiinipes, being most abundant. A few beetles were also found to be external chewers. Adult Dichelonyx fed on the host plant in July at CRMO. Anisostena califor- nica, a chrysomelid, was observed feeding on wildrye leaves at both sites. Larvae of three species of Hymenoptera fed internally in the grass culm. Cephus cinctiis larvae tunneled down the stems consuming parenchyma and vascular tissues. Larvae eventually cut the stems and overwintered in the remaining stubs. Sawfly herbivory may impair transport of water and nutrients through the stem, thus detrimentally affect- ing grain production (Holmes 1977, Seamans et al. 1944). Jointworms, Tetramesa spp., were reared from wildrye culms. Tetramesa larvae fed on internal tissues. At least one species formed "bump galls" on the stem be- low the inflorescence. Spears and Barr (1985) reported that these larvae adversely affect the growth and reproduction of several range grasses. Dipteran larvae, probably chloro- pids, were also collected within the stems but could not be reared to adults. Although injury due to defoliators is more apparent, fluid-feeding Homoptera and Hemiptera may have the greatest impact on wildrye and other native grasses (Haws 1982). By extracting plant fluids and pumping saliva into the plant, these insects remove essential plant sap and cytoplasm and may inject toxic compounds or transmit viruses. Cicadas, Okanogana bella, were very visible in the summer clinging to wildrye stems at CRMO. Leafhoppers and delphacids were the most common insects feeding on wildrye. Over 50 individuals of a delphacid, Eurysa ohesa, were counted at one time on an individual 646 Great Basin Naturalist Vol. 47, No. 4 Table 1. Insects collected and observed feeding on Great Basin wildrye at Craters of the Moon National Monument (C) and the Idaho National Engineering Laboratory Site (I) in 1982-83. Taxa Life stage^ Plant parts' Location Host spec." Abundance Orthoptera Acrididae Melanopltis bivittatus (Say) Melanophis femur rubrum (DeGeer) Melanoplus foediis Scudder Melanopltis sanguinipes (Fabricius) Phoetaliotes nebrascensis (Thomas) Thysanoptera Aeolothripidae Aeolothrips auricestus Treherne Aeolothrips sp. Thripidae Aptinothrips rufus (Gmelin) Frankliniella occidentalis (Pergande) Frankliniella sp. Sericothrips sp. HOMOPTERA Cicadidae Okanogana bella Davis Cicadellidae Dikraneura carneola (Stal) Hecahis viridis (Uhler) Delphacidae Eurysa obesa Beamer Aphididae For da marginata (Koch) Forda olivacea Rohwer Pseudococcidae Cryptoripersia trichura (Cockerell) Phenacoccus sp. Trionymus smithii (Essig) Eriococcidae Eriococcus insignis Newstead Hemiptera Miridae Irbisia pacifica (Uhler) Labops iitahensis Slater Litomeris debilis (Uhler) Stenodenia laevigatum (Linnaeus) Pentatomidae Aelia americana Dallas Rhytidilomia uhleri Stal Coleoptera Elateridae Anchastus cinereipennis Eschscholtz Cardiophorus sp. Limonius infuscatiis Motschulsky Limonius sp. Melyridae Attains glabrellus Fall Attains rnortdus smithi Hopping Collops bipunctus (Say) Anthicidae Notoxus serratus LeConte Phalacridae Phalacrus pencillatus Say Scarabaeidae Dichelonyx sp. n, a c,l c P CO n, a c, 1 C P CO n, a c,l C P un n, a c,l C, I P CO n, a c, 1 C 0 CO a f,s C, I P CO n, a f,s C, I u CO a f,l C, I 0 CO n, a f, s C, I p CO n, a f, s C u CO n, a f, s C, I u CO a c, 1 C P CO n, a c, 1 C, I p CO n, a 1 I p CO n, a c, 1 C, I n, a r I o un n, a r C 0 un n, a r C 0 un n, a r I u un n, a c,l c 0 CO n, a c,l c o un n, a c, 1 C, I o CO n, a c, 1 c o CO n, a c, 1 C, I o CO n, a c, 1 C, I o CO a f, 1 C, I P CO a f C, I 0 CO 1 r C,I o CO 1 r c u CO 1 r c 0 CO 1 r I u CO a f I p CO a f I p CO a f I p CO a f, s C, I p CO a f C, I p CO 1 r c u CO a c,l c u CO October 1987 YOUTIE ET AL.: WiLDRYE INSECTS IN IDAHO 647 Table 1 continued. Ta\a Life stage'' Plant parts' Location Host spec' Abundance'' Cerambycidae Cortodera barri Linsley & Chemsak Chrysomelidae Alt tea sp. Anisostcna californica Van Dyke Curculionidae Brachyrhiniis ovatiis (Linnaeus) Sphenophorus gentilis LeConte Lepidoptera Noctuidae Faronta diffusa (Walker) Hymenoptera Cephidae CephtiS cinctus Norton Eurytomidae Tetramesa ehjmophaga (Phillips) Tetramesa sp. r C, I o ra f C, I P CO f C, I u CO 1 C, I o CO r C p CO r I 0 — s I 0 CO f,s c(i) c(i) c(i) C, I C, I C, I C, I CO CO "n = nymph, 1 larva, a = adult. c = culm, l = leaf, r = root, f=flower, s seed, (i) internal '^p = polyphagous, o = oligophagous, m- monophagous, u unknown ra^rare (fewer than 10 insects collected), un -uncommon (10-50 insects collected), co common (more than 50 insects collected). Table 2. Insect parasitoids reared from insect hosts in Great Basin wildrye culms collected from Craters of the Moon National Monument (C) and the Idaho National Engineering Laboratory (I) in 1983. Taxa Host Location Hymenoptera Eulophidae Pediobius utahensis (Crawford) Zagrainmosoma nigrolineatum Crawford Eupelmidae Calosota sp. Torymidae Torymus thalassinus (Crosby) Pteromalidae Homoporus atriscapus Gahan Homoporus sp. Eurytomidae Eiirytoma pachynetiron Girault Eurytoma sp. Cephus cinctus Nort. unknown'' Tetramesa sp. Tetramesa sp. unknown Tetramesa sp. Tetramesa sp. Tetramesa sp. C, I I I I C c c C, I "Previously reported to be a parasite on Argyresthia sp. (Lepidoptera; Yponomeutidae) (Krombein et al. 1979). Probably parasitic on Tetramesa sp. grass tiller. Less common were the scales found on the stems under the leaf sheaths. Impacts from these Homoptera could not be separated from the damage due to the fluid- feeding hemipterans. Many species of mirids cause injury to range grasses through toxemia and loss of plant fluids (Watts et al. 1982). Irbisia pacifica, Litomeris debilis, and Stenodema laevigatum frequently fed on wildrye at both sites. In June 1983 at CRMO, a large section of the study site was observed turning brown. Basin wildrye plants were stunted in the four- leaf stage by infestations of the black grass bug, Labops utahensis, and the delphacid Eu- rysa obesa. When insect numbers declined later in the summer, wildrye resumed growth but did not produce any reproductive tillers. Adequate soil moisture and carbohydrate re- serves may have enabled the plants to re- cover. However, the black grass bug can significantly reduce forage production and may cause death if droughty conditions pre- vail (Todd and Kamm 1974, Haws 1978). 648 Great Basin Naturalist Vol. 47, No. 4 Table 3. Sorensen coefficients of insect community similarity by guild on Great Basin wildrye at Craters of the Moon National Monument (CRMO) and the Idaho National Engineering Laboratory (INEL) in 1982 and 1983. Number of species Guilds CRMO INEL Common sr Fluid-feeders — roots 2 2 0 0.00 Chewers — roots 3 2 1 0.40 Fluid-feeders — leaves & culms 14 11 8 0.64 Chewers — leaves & culms 10 4 3 0.43 Fluid-feeders — flowers & seeds 5 4 4 0.89 Chewers — flowers & seeds 2 3 2 0.80 Internal chewers — culms 3 3 3 1.00 Internal parasites 5 5 2 0.40 Pollen feeders 6 9 6 0.80 Total species'' 45 38 26 0.62 ^SI= 2 (Common) CRMO + INEL (Sorensen 1948, Wolda 1981). Columns do not add up to total because some insects overlap guilds. Flower- and Seed-Feeders Thrips, pentatomids, adult beetles, and lar- vae of a species of Lepidoptera were collected on wildrye inflorescences. Seven species of beetles consumed the pollen. Most of these beetles were polyphagous herbivores that switch hosts to take advantage of the available nutritious food source (Thomas and Werner 1981). This may also have been true of the pentatomids that were found feeding on the developing seeds. However, adult billbugs seemed to be monophagous on wildrye in this area. They were observed chewing on the developing seeds o^Elymus. After seed matu- ration, adult billbugs were no longer ob- served. Thrips were collected throughout the season. Two families and six species of Thysanoptera were represented in the Great Basin wildrye insect community. Franklin- iella occidentalis, the western flower thrip, is a widespread, generalist feeder that has previ- ously been reported on grasses (Tingey et al. 1972, Watts and Bellotti 1967, Knowlton and Thomas 1933). Thrips are often cited as caus- ing damage to grass seed (Thomas and Werner 1981, Riherd 1954, Bafley 1948). The only lepidopteran associated with wildrye, Faronta diffusa, fed on the inflorescences at both sites. This species is especially destruc- tive to wheat, oats, and rye (Walkden 1950) and has been reported on a variety of native grasses in Arizona, New Mexico, and Utah (Godfrey 1972, Watts and Bellotti 1967). Parasites Eight chalcid parasitoids (Hymenoptera: Chalcidoidea) were reared from insect hosts in Great Basin wildrye culms. Pediobius uta- hensis was reared from sites of developing wheat stem sawflies in stubs of wildrye culms. The other chalcid parasitoids were collected within the culms in the second, third, and fourth internodes and were associated with Tetramesa species. It is not known whether any of these wasps were hyperparasites. Herbivore Guild Complexity Twenty-six of the 46 insect species col- lected on basin wildrye were found at both the CRMO and INEL sites (Table 3). Presence or absence of a species was utilized as an indica- tor of insect fauna similarity between sites. Similarity indices were estimated using Sorensen's (1948) coefficient (Wolda 1981). Each guild was examined individually. Inter- nal chewers and flower and seed feeders dis- played the greatest similarity. The small num- ber of grasshopper species at the INEL site may account for differences in leaf and culm external chewers. Low similarity indices for root insects may reflect the very different soil types of the two stands. Although occurring only 40 km apart, the CRMO and INEL sites are different habitat types and represent the wide ecological amplitude of basin wildrye. Climatic and edaphic differences may account for much of the difference in insect species collected from each site. The majority of the species that constitute the wildrye herbivore guilds are oligopha- gous, also feeding on cultivated grains as well as other native and introduced grasses. Rangelands are thought to be a source of most insect pests of cereal grains (Watts et al. 1982). October 1987 YOUTIE ETAL: WiLDRYE INSECTS IN IDAHO 649 Wildrye, a large, structurally diverse plant, supports a sizable fauna and thus may serve as a reservoir for many of these herbivores. However, wildrye stands also may function as reservoirs for potentially useful predator and parasite species. The number of phytophagous insect species exploiting Great Basin wildrye was quite large relative to other native grasses in the area. Very few studies have identified the total phy- tophagous insect community associated with an individual grass species. Watts (1963) col- lected 120 species on black grama grass, Bouteloua eriopoda Torrey; however, these included grass-feeders, parasites and preda- tors, and casual visitors. Wight (1986) identified 33 phytophagous insects on the in- troduced crested wheatgrass, Agropyron cristatum (L.) Gaertn., in southern Idaho. Beisler and his colleagues (1977) collected phytophagous insects associated with three weedy grasses. They found 33 species feeding on Johnson grass. Sorghum halepense (L.) Pers.; 39 on fall panicum, Panicum di- chotomiflorum Michx. ; and 35 associated with large crabgrass, Digitaria sanguinalis (L.) Scop. Plant structural diversity, species area rela- tionships, and taxonomic isolation are thought to explain much of the richness of insect spe- cies on a host plant (Lawton and Schroder 1977, Southwood 1961, Strong and Levin 1979). Grasses and forbs are less structurally diverse than trees and shrubs and usually have fewer associated species (Niemela et al. 1982, Strong et al. 1984). However, wildrye's height and foliage diversity provide a greater variety of microhabitats than do most range grasses. Tallamy and Denno (1979) found the more structurally complex grass Distichlis spi- cata (L.) Greene supported a richer commu- nity of sap-feeders than the simpler Spartina alterniflora Loisel. Taxonomically isolated plants may have im- poverished insect faunas (Strong et al. 1984). Wildrye belongs to the grass tribe Triticeae. Idaho is included as one of the areas of the world with the greatest concentrations of spe- cies in this tribe (Hartley 1972). Therefore, many closely related grass genera, such as Agropyron, Sitanion, and Hordetim, are well represented in the area. Many insects that feed on wildrye are likely to feed on alternate hosts in related genera, thus increasing the geographical area they may exploit. Insect species found on a particular host plant are influenced by the local abundance of the plant, both its density and extent (Strong et al. 1984, Fowler and Lawton 1982, Root 1973). On the study sites wildrye grew in almost pure stands, but in very different habi- tats. Wildrye has a large geographic range, grows in a variety of habitat types (Walker and Brotherson 1982), and is locally abundant within these types. Insects feeding on this grass find a large, conspicuous food source that remains available longer into the summer than any other C3 grass species in the area. Graminivorous insects were identified that have the potential to reduce forage and seed production of wildrye. This information may be valuable to grass breeders, seed compa- nies, and range managers interested in reveg- etation of certain types of rangelands with basin wildrye. Some of the phytophagous in- sects in this study apparently reduced repro- ductive potential of wildrye and may have detrimental effects on reseedings. Although grasses are very tolerant of herbivory and have evolved many means of tolerating graz- ing (McNaughton 1979, Stebbins 1981), in- sect populations fluctuate greatly and in some years could reach injurious levels. Therefore, it is important to identify which plants and plant parts are fed upon by various members of the insect community and to determine the impact of herbivory on an individual plant species and its population dynamics. Acknowledgments We thank O. D. Markham, U.S. Depart- ment of Energy, Idaho National Engineering Laboratory Site, and the staff at Craters of the Moon National Monument for their coopera- tion and logistical support. We appreciate the helpful suggestions of Drs. J. P. McCaffrey and M. A. Brusven, University of Idaho, while preparing this manuscript. Apprecia- tion is also extended to Frank Merickel, Uni- versity of Idaho, and the many other entomol- ogists who assisted in identifying specimens. This study was funded by the University of Idaho, College of Agriculture. 650 Great Basin Naturalist Vol. 47, No. 4 Literature Cited Asay, K H , J D Hansen, B A Haws, P O Currie 1983. Genetic differences in resistance of range grasses to the bluegrass billbug, Sphenophorous parvulus (Coleoptera: Curculionidae). J. Range Manage. 36: 771-772. Bailey, S. F. 1948. Grain and grass infesting thrips. J. Econ. Entomol. 41; 701-706. Bailey, S. F , and G F Knowlton 1949. The Thysan- optera of Utah. Proc. Entomol. Soc. Washington 51:231-234. BEISLER, J. M , R L PlENKOWSKI, LT KOK, AND W H Robinson. 1977. Insects associated with three weedy grasses and yellow nutsedge. Environ. En- tomol. 6; 455-459. 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Four- Corners Regional Commission, Project No. 602- 466-080-4. 50 pp. TiNGEY, W M , C D Jorgensen, and N C Frisch- KNECHT 1972. Thrips of the sagebrush-grass range community in west-central Utah. J. Range Manage. 25: 304-308. October 1987 YOUTIE ET AL: WiLDRYE INSECTS IN IDAHO 651 ToDD.J G.andJ. A. Kamm, 1974. Biology and impact of a grass bug Lahops hesperius Uhler in Oregon rangeland. J. Range Manage. 27: 453-458. WalkDEN, H M 1950. Cutworms, armyworms, and re- lated species attacking cereal and forage crops in the central plains. USDA Circ. 849. 52 pp. Walker. G. R, andJ D Brotherson 1982. Habitat rela- tionships of basin wildrye in the high mountain valleys of central Utah. J. Range Manage. 35: 628-633. Watts, J G 1963. Insects associated with black grama grass, Bouteloua eriopoda. Entomol. Soc. Amer. Ann. 56: 374-379. Watts, J G . and A C Bellotti 1967. Some new and little known insects of economic impor- tance on range grasses. J. Econ. Entomol. 60: 961-963. Watts, J G ,E W Huddleston, andJ, C. Owens. 1982. Rangeland entomology. Ann. Rev. Entomol. 27: 283-311. Wight, R 1986. Insect fauna of a crested wheatgrass habitat in the Raft River Valley of southern Idaho. Unpublished thesis. University of Idaho, Mos- cow. 120 pp. WoLDA, H. 1981. Similarity indices, sample size and di- versity. Oecologia 50: 296-302. EFFECTS OF FOREST FUEL SMOKE ON DWARF MISTLETOE SEED GERMINATION G. Thomas Zimmerman' and Richard D. Laven' Abstract. — Seeds of three species of dwarf mistletoe, Arceuthobium americanum Nutt. ex Engelm., A. cyanocarpum Coulter & Nelson, and A. vaginatum subsp. cryptopodwn (Engelm.) Hawksw. & Wiens, were exposed to smoke from burning forest fuels. Premeasured amounts of coniferous needles and branch wood were burned in a small incinerator with smoke passing through a closed chamber containing the seeds. Following three different smoke treatments and one high-temperature treatment, tests were conducted to evaluate the effects of these treatments on seed germination. Germination was inhibited for all species when the seeds were exposed to smoke for 60 minutes or longer. Seeds of A. americanum were unaffected by exposures of up to 40 minutes from fuels with high moisture contents, but enhanced germination occurred after 30 minutes of exposure to smoke from drier fuels. The percentage of germinating seeds of A. cyanocarpum and A. vaginatum showed Httle effect from exposures of up to 30 minutes. Dwarf mistletoe species (Arceuthobium spp.) are the most serious of diseases in conif- erous forest communities of western North America (Alexander and Hawksworth 1975). These plants are obligate parasites that attack specific coniferous host tree species and ap- propriate water, minerals, and other nutri- ents from the host. Injury to infected trees results in a continual reduction of host assimi- latory leaf-surface area (Weir 1916, Korstian and Long 1922), decreased growth, reduced vigor, and increased mortality (Hawksworth 1961, 1975, Wicker and Leaphart 1976). Hawksworth and Wiens (1972) discuss dwarf mistletoe biology and host reaction exten- sively. Wildfires, which occurred repeatedly in coniferous forest communities prior to the ad- vent of organized fire suppression (Weaver 1951, Wellner 1970, Arno 1976, McRride and Laven 1976, Stokes and Dieterich 1980), are a major ecological force that influenced forest structure and development and also signifi- cantly affected dwarf mistletoe population dy- namics (Gill and Hawksworth 1964, Baranyay 1970, Wicker and Leaphart 1976, Tinnin 1981). Fire affects dwarf mistletoes directly by killing and consuming host tissues and para- sitic plants. These effects are dramatic, imme- diate, readily observable, and well known. The indirect relationships of fire to dwarf mistletoes, such as reduction of growth or vigor in hosts and parasites, loss of parasite seed viability, or predisposition of hosts to other damaging agents, may be caused by exposure to smoke or elevated temperatures. These effects are subtle, gradual, and difficult to observe. The effects of forest fire smoke exposure on dwarf mistletoe growth and de- velopment are unknown and constitute an area of necessary research (Alexander and Hawksworth 1975, Hardison 1976, Koonce and Roth 1980, Smith 1981). Several workers have reported the effects of smoke on various disease-causing agents. Long (1922) observed that mistletoe (Phoradendron spp.) parasitizing one seed ju- niper (Juniperus monospenna [Engelm.] Sarg.) died after exposure to smelter smoke. Spore germination, mycelial growth, and in- fection of several species of fungi are inhibited after exposure to pine needle and grass smoke (Parmeter and Uhrenholdt 1975). Koonce and Roth (1980) suggested that heat and smoke may affect dwarf mistletoe plants (Arceutho- bium campijlopodum Engelm.) more severely than the associated host plants (Finns pon- der os a Laws.). This study will improve our understanding of the indirect relationships of fire and dwarf mistletoe. The primary objective was to eval- uate the effects of various durations of forest fuel smoke exposure on seed germination of three dwarf mistletoe species. Department of Forest and Wood Sciences, Colorado State University, Fort Collins, Colorado 80523. 652 October 1987 Zimmerman, Laven: Smoke Effects on Mistletoe 653 Materials and Methods Dwarf mistletoe, A. americanum, seeds were collected from lodgepole pine (Pinus contoria Dougl.), A. cyanocarpum were col- lected from limber pine (Pinus flexilis James), and A. vaginatum were collected from pon- derosa pine in a manner similar to that dis- cussed by Scharpf and Parmeter (1962). These seeds were then placed in petri dishes (50 per dish) and stored in a refrigerator at 6 C for equal time periods until ready for treatment. A smoking apparatus, similar to that described by Parmeter and Uhrenholdt (1975), was constructed from a small wood stove, uninsulated duct pipe, and a refrigera- tor. Smoke from burning fuels in the wood stove passed into a 10-cm-diameter duct pipe and traveled 5.5 m through this uninsulated pipe to allow cooling and to minimize heat effects. The pipe entered the bottom of the refrigerator, permitting smoke movement through shelves supporting the petri dishes upward and outward through the refrigerator roof. Use of wire mesh shelves and a small electric fan promoted a somewhat even distri- bution and movement of smoke through the chamber. Three smoke treatment experiments were conducted. First, samples of seeds of all three dwarf mistletoe species were exposed to smoke for 0 (control), 60, and 180 minutes. Second, samples of all three species were ex- posed to smoke for 0, 1,5, 15, and 30 minutes. Third, samples of only A. americanum seeds were exposed to smoke for 0, 10, 20, 30, 40, 50, 60, and 90 minutes. Ponderosa pine, lodgepole pine, and Dou- glas-fir {Pseudotsuga menziesii [Mirb.] Franco) needles and branch wood were used to generate smoke. This fuel was collected from the forest floor duff layer. Moisture con- tent and weight of fuels consumed were deter- mined prior to each experiment. Air tempera- tures inside and outside the smoking chamber were recorded during the exposure periods. Chemical composition of smoke was analyzed for polynuclear aromatic hydrocarbons (PAH), a common pollutant in combustion emissions. Analysis methods are reported in Tan et al. (1985)' Separate germination tests were conducted with A. americanum seeds in an attempt to assess the effects of high temperatures on ger- mination. Only A. americanum^ seeds were used in this test as well as in the third smoke treatment experiment because seeds of the other species were not available in sufficient quantities for collection and treatment. The A. americanum seeds were exposed to ele- vated temperatures for selected time periods in a portable heating apparatus. The heat treatment chamber was con- structed of lightweight aluminum and insu- lated with 2.54-cm insulation board. A small electric fan was attached to the bottom of the box along with the heat source, a 750-watt ceramic heating coil screwed into a 110-volt electric light socket. An aluminum shelf, insu- lated on the upper side, was placed directly above the heating element to shield petri dishes and dwarf mistletoe seeds from direct heat. This shelf was open on both sides, and the continuously operating fan promoted movement of heated air around the shield into the space occupied by the dishes and seeds. Air temperatures inside the treatment chamber were controlled by a separate con- trol box. This device possessed time and tem- perature control features which enabled the setting of a desired temperature and time pe- riod on the dial panel. The control box auto- matically activated the heating element as needed to attain the desired temperature. Af- ter the preset temperature was achieved, the timer engaged and the heating element oper- ated as needed to maintain the internal tem- perature. Following operation for the preset time period, the control box disengaged both the timer and the heating element, allowing the chamber to cool down. A solid-state, two- terminal, integrated circuit temperature transducer attached to the control box circuit board monitored the chamber air tempera- ture. This transducer permitted the control box to maintain the chamber temperature within ± 0.5 degrees C. A thermometer placed inside the treatment chamber pro- vided a check of the temperature controller. Elevated temperature treatments included time periods of 30 and 45 minutes for both 35 and 40 C, and 2, 5, and 10 minutes for 45 and 50 C. An unexposed group was used for com- parison. These temperatures and durations were selected to correspond to the tempera- ture environments within the smoke treat- ment chamber during smoke experiments. ■ 654 Great Basin Naturalist Vol. 47, No. 4 Table 1. Air temperature (°C) during smoke treatment experiments. Rvp.H,r..nf T.n.p.r.H.r.' Time (minutes) number location 0 1 5 10 15 20 30 40 50 60 90 120 150 180 12 17 17 21 10 9 12 14 13 12 12 40 40 43 46 41 17 21 17 21 19 23 21 31 10 11 12 13 16 18 18 18 23 25 30 35 32 35 37 37 38 44 Temperature locations are signified as 0 = outside ambient air temperature, I - air temperature inside smoke treatment chamber. Table 2. Average percent germination of A. ameri- canum seeds after exposure to temperatures and dura- tions that occurred during smoke treatments. Time (minutes) Temp rC) 2 5 10 30 40 35 35.6 18.8 40 — — — 38.8 6.4^ 45 30.8 28.8 26.4 — — 50 50.8^ 24.0 6.0^ — — Average germination of the untreated group used for comparison 26.8%, Average percent germination significantly higher than untreated group. Average percent germination significantly lower than untreated group. After exposure to smoke or high tempera- tures, treated and untreated seeds were im- mersed in a 2% hydrogen peroxide solution to inhibit ftmgal attack and facilitate maximum germination (Wicker 1974). The seeds were then placed in a standard germination cham- ber for 30 days and maintained at 16 C with an 8-hour light treatment during each 24-hour period. A visible radicle that ruptured the endocarp was taken as positive evidence of germination (Knutson 1969). Statistical analy- ses that compared average percent germina- tion of treated and untreated groups were conducted with one-way analysis of variance and Duncan's Multiple Range Test. The .05 level of statistical probability was selected as significant. Results During the initial experiment, 3,235 g of fuel averaging 8% moisture content (oven-dry basis) was consumed. In the second experi- ment, 1,816 g of fuel having a moisture con- tent of 25% was burned, while in the final experiment 4,225 g of fuel with an average moisture content of 34% was consumed. Maximum air temperatures outside the treatment chamber varied from 12 to 23 C for the three experiments (Table 1). Inside cham- ber temperatures showed a gradual increase in all experiments, with the maximum reach- ing as high as 46 C (Table 1). Although inside air temperatures exceeded outside air tem- peratures throughout most of the experi- ments, the maximum inside temperature per- sisted for a relatively short time. Analyses of smoke particulates to assess PAH composition were conducted on both the wood and duff fuel used in the study. Composition of PAH from wood burning was found to resemble that from other environ- mental samples such as air particulates and sediments where parental PAH are the pre- dominant components (Tan et al., unpub- lished manuscript). Duff burning, however, illustrated a PAH composition markedly dif- ferent from the composition in environmental samples such as air, sediments, and wood- burning emitted particulates. In typical environmental samples, parental PAH generally make up the major compo- nents. In smoke particles from duff burning, phenanthrene, alkylated phenanthrene, alky- lated cyclopenta(def)phenanthrene, and do- decahydrochrysene clearly stood out as the predominant components (Tan et al., unpub- lished manuscript). In addition, the concen- tration of individual PAH in smoke particles varied with moisture content of burning duff, but not in a systematic way for all components (Tan et al., unpublished manuscript). No ready explanation is available for this occur- rence. Exposure of dwarf mistletoe seeds to ele- vated temperatures for different periods of time resulted in variable seed germination (Table 2). While average percent germination of seeds did not continually decrease as time and temperature increased, it was lowest after treatment. After heating at temperatures of 40 October 1987 ZiMME Percent ger 100 ^mination 90 - 80 ■ 70 - 60 - 50 - 40 ■ 30 - 20 - 10 0 - Zimmerman, Laven; Smoke Effects on Mistletoe 655 Ar Va y^Ar Cy 5o3 Ar Am ^ggg^ 0 60 180 Duration of Smoke Exposure (Minutes) Fig. 1. Average percent germination of Arceuthohium vaginatum (Ar Va), A. cyanocarpum (Ar Cy), and A. americanum (Ar Am) in relation to duration of smoke exposure from fuels with 25% moisture content. Percent germination 100 0 1 5 15 Duration of Smoke Exposure (Minutes) Fig. 2. Average percent germination of Arceuthohium vaginatum (Ar Va), A. cyanocarpum (Ar Cy), and A. americanum (Ar Am) in relation to duration of smoke exposure from fuels with 8% moisture content. C for 40 minutes, average percent germina- tion was significantly reduced (Table 2). Ger- mination was unaffected when exposed to 45 C. Treatment at a still higher temperature (50 C) appeared to stimulate germination at low durations (2 min), while inhibiting germina- tion after 10 minutes (Table 2). Exposure of dwarf mistletoe seeds to differ- ent smoke durations caused varying results, depending on the moisture content of the fu- els consumed (Figs. 1-3). Average percent seed germination of all dwarf mistletoe spe- cies was markedly reduced after smoke expo- sure of 60 minutes or more regardless of the fuel moisture content (Figs. 1, 3). Average percent germination of A. ameri- canum seeds varied with both duration of smoke exposure and fuel moisture content (Figs. 1-3). Smoke exposure of 20 minutes or less had no effect on germination in all 656 Great Basin Naturalist Vol. 47, No. 4 Percent germination 100 Ar Am 10 20 30 40 50 50 Duration of Smoke Exposure (Minutes) Fig. 3. Average percent germination oiArcenthobium americanum (Ar Am) in relation to duration of smoke exposure from fuels with 34% moisture content. experiments except that exposure to smoke from moist fuels for 10 minutes resulted in significantly lower average percent germina- tion (Fig. 3). However, this trend was not consistent because both untreated seed groups and groups exposed for longer dura- tion had significantly higher germination per- centages (Fig. 3). This apparent anomaly may have resulted from factors other than expo- sure to forest fuel smoke. Exposure of seeds of this species to smoke for 30 minutes from fuels with a low moisture content resulted in aver- age percent germination levels significantly higher than seeds in the unexposed group (Fig. 2). However, 30 minutes of smoke expo- sure from fuels with high moisture contents resulted in no significant differences in aver- age percent germination (Fig. 3). Exposure to smoke from fuels with high moisture content for longer than 40 minutes caused a significant decrease in the germination of A. americanum seeds (Fig. 3). The percentage of germinating seeds exposed to 60 minutes of smoke was less than one-twelfth of the average germination for the untreated groups in both the first and third experiments (Figs. 1, 3). No A. ameri- canum seeds germinated after smoke expo- sure reached 90 minutes (Figs. 1,3). Average percent germination of A. cyano- carpum seeds exposed to smoke for 0, 1,5, 15, and 30 minutes did not differ markedly (Fig. 2). However, average percent seed germina- tion was significantly reduced after exposure to smoke for at least 60 minutes (Fig. 1). Germination percentages of A. vaginatum were considerably lower than those of the other species for all treatments including the controls (Figs. 1, 2). Germination of A. vagi- natum seeds decreased slightly as smoke ex- posure increased but was not significant until exposure periods exceeded 30 minutes. Discussion Substantially lower seed germination per- centages of all dwarf mistletoe species when smoke exposures exceeded 30 minutes may result from several factors: (1) a threshold level of smoke toxicity to seeds, (2) chemical toxicity of various fuel types, (3) temperature, and (4) lack of air mixing around the plants. The occurrence of PAH in the combustion products of carbonaceous fuels agrees with Sandberg et al. (1979). In a study of PAH production from laboratory burning of pine needles with moisture contents ranging from 18 to 27%, McMahon and Tsoukalas (1978) report that heading fires appear to produce higher total particulate matter but lower PAH values than backing fires. Within heading fires, PAH levels also vary as the fire phase varies. Flaming phases produce lower levels of both total particulate matter and PAH than smoldering phases. Specific causes of these October 1987 Zimmerman, Laven; Smoke Effects on Mistletoe 657 effects are hard to pinpoint, but apparently the longer residence times associated with backing and smoldering fires are more condu- cive to PAH -compound formation. Increasing moisture in fuels should result in lower combustion efficiency, thereby increas- ing residence time and PAH production. But, fuels burned with the lowest moisture content (8%) caused the greatest total PAH produc- tion (Tan et al. , unpublished manuscript). To- tal PAH production was lowest in smoke pro- duced from the fuels having the highest moisture content. Since individual PAH con- centrations varied in an unsystematic fashion as fuel moisture content increased, the influ- ence of specific compounds on seed germina- tion appears to be more important than the influence of total PAH production. Exposure duration is a major factor deter- mining the degree of injury from compounds contained in or formed as a result of smoke (Jensen and Dochinger 1974, Dochinger and Jensen 1975). Smoke contains or results in formation of numerous compounds, primarily oxidants (Cramer 1974, Evans et al. 1977), which are toxic at relatively low levels to vege- tation. Smoke in low doses can have minor effects on plant physiological processes, while high doses can result in acute toxicity and tissue necrosis (Sandberg et al. 1979). Structure of the smoke treatment chamber failed to remove all possible effects of high- temperature exposure on seed germination. Separate tests completed with the heating ap- paratus, however, did effectively isolate this source of variation. Average percent germina- tion of those seeds exposed only to elevated temperatures did not follow any consistent trends. Although differential viability may have been responsible for these inconsisten- cies, it was not assessed in either the smoke or temperature treatments. The fact that differ- ential viability had an equal probability of in- fluencing the percent of seeds germinating after exposure to smoke or high temperatures indicates that it had little effect on the ob- served outcome. Seeds exposed to temperature environ- ments in the heating apparatus (which corre- spond to temperature environments within the smoke treatment chamber) showed reduc- tions in average percent germination only af- ter long exposure. Thus, it appears that at these temperatures for exposures of less than 60 minutes, smoke was the major factor influ- encing dwarf mistletoe seed germination. As exposure exceeded 60 minutes, the tempera- ture treatment became an increasingly impor- tant factor affecting seed germination. After longer durations (90 minutes), the combined effects of the temperatures used in this study and smoke appear lethal to dwarf mistletoe seeds. Average percent germination of A. vagina- turn seeds was significantly lower than the other species for all treatments, including the control. Conceivably, lower germination per- centages of A. vaginatum seeds may indicate that the other species have evolved ecological adaptations to smoke exposure. Seeds of A. vaginatum commonly mature four to six weeks before the seeds of A. ainericanum and A. cijanocarpum. Upon reaching maturity, A. vaginatum seeds are expelled from the fruit and germinate within a short period of time. Seeds of A. americanum and A. cijanocarpum mature in late August or early September and are expelled onto the host material. They then overwinter on the twig and germinate the following May. Consequently, A. vaginatum seeds are susceptible to smoke exposure for a much shorter period of time than those of the other species. Frequent smoke exposure may have permitted seeds of A. americanum and A. cijanocarpum to evolve mechanisms that promote successful germination in the pres- ence of smoke of low concentrations for short durations. Summary Fire is one of the principal agents prevent- ing parasitic species from overrunning host populations (Tinnin 1981). Smoke from fire is a common occurrence in many coniferous forest communities. Although the preserva- tive properties of smoke are well known (Fra- zier 1967), the specific effects of smoke expo- sure on dwarf mistletoe growth and development have not been documented. Results reported here indicate that pro- longed smoke exposure inhibits dwarf mistle- toe seed germination. After continuous expo- sure for more than 60 minutes, smoke, and the accompanying increase in temperatures, both severely limit dwarf mistletoe seed ger- mination. Brief exposure to smoke from fuels with low moisture contents causes increased 658 Great Basin Naturalist Vol. 47, No. 4 germination of A. americanum seeds but has little effect on A. cyanocarpiwidndA. vagina- tum seed germination. Other relationships between fire and dwarf mistletoes are still not well understood. Fu- migation of coniferous forests by smoke from wildfires may affect plant development, polli- nation, fruit maturation, and infection by dwarf mistletoes. Smoke may have secondary effects on these parasites by affecting host vigor. Although this paper by no means addresses all of the relationships between fire and dwarf mistletoe, it does provide new ecological in- formation concerning the effects of forest fuel smoke on dwarf mistletoe seed germination. Literature Cited Alexander, M E , and F G Hawksworth 1975. Wildland fires and dwarf mistletoes: a literature review of ecology and prescribed burning. USDA For. Serv. Gen. Tech. Kept. RM-14. Rocky Mtn. For. Range Expt. Sta., Fort Collins, Colorado. 12 pp. Arno, S. F 1976. The historical role of fire on the Bitter- root National Forest. USDA For. Serv. Res. Pap. INT-187. Intmtn. For. Range Expt. Sta., Ogden, Utah. 29 pp. Baranyay, J. A. 1970. Lodgepole pine dwarf mistletoe in Alberta. Canada Dept. Fish, and Forest., Cana- dian Forest. Serv. Publ. 1286. 22 pp. Cramer, O P 1974. Air quality influences. In. Environ- mental effects of forest residues management in the Pacific Northwest. USDA For. Serv. Gen. Tech. Rept. PNW-24. Dochinger, L. S , AND K. F Jensen 1975. Effects of chronic and acute exposure of sulfur dioxide on the growth of hybrid poplar cuttings. Environ. Pollut. 9; 219-229. Evans, L F., I A Weeks, A J Eccleston, and D R Packham. 1977. Photochemical ozone in smoke from prescribed burning of forests. Environ. Sci. Tech. 11:896-900. Frazier, W C, 1967. Food microbiology. McGraw-Hill Book Co. , New York. 537 pp. Gill, L. S , and F G Hawksworth. 1964, Dwarf mistle- toe of lodgepole pine. USDA For, Pest Leafl. 18 (rev.). 7 pp. HardisoN, J. R 1976. Fire and flame for plant disease control. Ann, Rev, Phytopathol, 14: 355-379, Hawksworth, F G 1961. Dwarf mistletoe of ponderosa pine in the Southwest. USDA Tech, Bull. 1246, Washington, D,C. 112 pp. 1975. Dwarf mistletoe and its role in lodgepole pine ecosystems. Pages 342-358 in D. M. Baum- gartner, ed.. Management of lodgepole pine ecosystems. Vol, 1, Washington State University, Pullman, October 1973. H.^wksworth, F G , and D Wiens 1972, Biology and classification of dwarf mistletoes (Arceuthobium). USDA Agric. Handb. 401. Washington, D, C. 234 pp. Jensen, K. F., and L. S Dochinger 1974, Responses of hybrid poplar cuttings to chronic and acute levels of ozone. Environ, Pollut, 6: 289-295, Knutson, D M 1969, Effect of temperature and relative humidity on longevity of stored dwarf mistletoe seeds. Phytopathology 59: 1035 (abstract), KooNCE, A L, AND L F Roth 1980, The effects of pre- scribed burning on dwarf mistletoe in ponderosa pine. Pages 197-203 in Proc, Sixth Conf on Fire and Forest Meteorol. Seattle, Washington, KORSTIAN, C. F , AND W H. LoNG. 1922. The western yellow pine mistletoe: effect on growth and sug- gestions for control. USDA Bull. 1112. Washington, D.C. 35 pp. Long, W. H 1922, Mistletoe and smelter smoke. Phyto- pathology 12: 535-536. McBride, J. R,, AND R. D, Laven. 1976, Scars as an indica- tor of fire frequency in the San Bernardino Moun- tains, California, J, Forest, 74: 439-442, McMahon, C. K , AND S N TsouKALAS 1978, Polynu- clear aromatic hydrocarbons in forest fire smoke. Pages 61-73 in P, W, Jones and R, I, Friedenthal, Carcinogens. Vol. 3, Polynuclear aromatic hydro- carbons. Raven Press, New York, Parmeter, J R , Jr , AND B Uhrenholdt 1975. Some effects of pine needle or grass smoke on fungi. Phytopathology 65: 28-31. Sandberg, D V , J M. Pierovich, D G. Fox, and E, W. Ross. 1979, Effects of fire on air: a state-of-knowl- edge review. USDA For. Serv. Gen. Tech. Rept. WO-9. Washington, D.C. 40 pp. ScHARPF, R F , and J R Parmeter, Jr, 1962. The collec- tion, storage, and germination of seeds of a dwarf mistletoe. J. Forest, 60: 551-.5.52. Smith, W H 1981, Air pollution and forests. Springer- Verlag, Inc., New York. 379 pp. Stokes. M. A., and J H Dieterich. 1980, Proceedings of the fire history workshop, USDA For. Serv, Gen, Tech, Rept, RM-81, Rocky Mtn. For. Range Expt. Sta., Fort Collins, Colorado. Tan, Y L , J F Quanci, R D Borys, and M J Quanci 1985, Polynuclear aromatic hydrocarbons and smoke particulates from wood and duff burning. Unpublished manuscript in file of U.S. Depart- ment of Energy, Environmental Measurements Laboratory, New York, New York. Tan, Y L , J F Quanci, M J Quanci. and R D, Borys, 1985. Polynuclear aromatic hydrocarbons in duff burning particulates. Page .5.55, abstract, Proc, 33d Ann, Conf on Mass Spectrometry and Allied Topics, Tinnin,R O. 1981, Interrelationships between Arce«f/io- bium and its hosts, Amer. Midi. Nat. 106: 126- 1,32, Weaver, H 1951. Fire as an ecological factor in the south-western pine forests. J. Forest. 49: 93-98. Weir, J R. 1916, Mistletoe injury to conifers in the North- west, USDA Bull, 360. Washington, D.C. 39 pp. October 1987 Zimmerman, Laven: Smoke Effects on Mistletoe 659 Wellner, C a 1970. Fire history in the northern Rocky For. Range Expt. Sta., Ogden, Utah. 28 pp. Mountains. Pages 41-64 in The role of fire in the Wicker, E F., andC D. Leaphart. 1976. Fire and dwarf Inter-mountain West, Synip. Proc. Missoula, mistletoe (Arcewf/iobiinnspp.) relationships in the Montana. northern Rocky Mountains. Tall Timbers Fire Wicker, E. F. 1974. Ecology of dwarf mistletoe seed. Ecol. Conf Proc. 14: 279-298. Missoula, Mon- USDA For. Serv. Res. Pap. INT-154. Intmtn. tana. October 1974. MICROVELIA RASILIS DRAKE IN ARIZONA: A SPECIES NEW TO THE UNITED STATES (HETEROPTERA: VELIIDAE) John T. Polhemus' and Milton W. Sanderson^ Abstract. — Microvelia rasilis Drake was taken in Montezuma Well, Yavapai Co. , Arizona, along with Microvelia hinei Drake and Hydrometra aemula Drake (Heteroptera; Hydronietridae). These are all new to this locality; however, the latter two species are previously known from Arizona. Recently we collected some Microvelia from Montezuma Well, Yavapai Co., Arizona, expecting that they would be M. hinei Drake 1920. Subsequent examination revealed two species, M. hinei and M. rasilis Drake 1951. In his revision of the genus, Cecil Smith (1980, A taxonomic revision of the genus Mi- crovelia Westwood [Heteroptera: Veliidae] of North America including Mexico, unpub- lished dissertation. University of Georgia, Athens, xv + 372 pp.) treated rasilis as a species only provisionally distinct from hinei. However, in the sample from Montezuma Well the two are distinct and easily separable by Smith's key characters. In hinei the dorsum of the thorax appears two-segmented with the mesonotum completely covered by the pronotum, the last two abdominal tergites have narrow, longitudinal median shining ar- eas, the coloration is yellowish with rather extensive, dark markings on the thorax and abdomen, and the size is distinctly smaller than rasilis. In rasilis the mesonotum is nar- rowly but distinctly exposed, the abdominal tergites are without median shining areas, the coloration is mostly light yellowish, and the size is distinctly larger. Microvelia hinei is a common, quite vari- able species widely distributed in the United States and Mexico, reaching Argentina to the south, and previously known from several lo- cations in Arizona (Smith 1980). On the other hand, M. rasilis is quite rare, known only from a few specimens, which led Smith to question its specific distinctness from hinei. The pres- ence of the two at one locality removes that doubt. The closest previous collection locality for rasilis was Telonzo, Michoacan, Mexico, 12-IV-1975, CL741, by J. T. Polhemus in a spring-fed pool among water hyacinths; this locality is about 1,900 km south of Montezuma Well. Other specimens in the Polhemus col- lection are from the Mexican states of Mexico and Puebla. Collection data for the Montezuma Well specimens are: M. hinei: 2 6,19, 8-VII- 1986, MWS; 7 9, 21-V-1987, MWS and JTP; 2 6,8 9, 8-VI-1987, MWS. M. rasilis: 2 9, 21-V-1987, JTP; 1 9, 8-VI-1987, MWS. The Montezuma Well collection of 21-V- 1987 also includes Hydrometra aemula Drake 1956, a species distributed in western Mexico and Arizona, but not previously known from this locality. Acknowledgments We are indebted to the United States Park Service for permission to collect in the Na- tional Monument, and to Cecil L. Smith for furnishing a copy of his dissertation. University of Colorado Museum, 3115 S, York. Englewood, Colorado 80110. Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona 86001. 660 INDEX TO VOLUME 47 The genera, species, and other taxa described as new to science in this volume appear in bold type in this index. A disjunct ponderosa pine stand in southeast- ern Oregon, p. 163. Age in relationship to stem circumference and stem diameter in cliffrose {Cowania mexi- cana var. stansburiana) in central Utah, p. 334. Allen, Douglas W., George W. Cox, and Christopher G. Gakahu, article by, p. 609. Allen, Richard K., and Chad M. Murvosh, article by, p. 283. Allredge, A. William, Douglas K. Halford, and W. John Arthur III, article by, p. 105. Alpine vascular flora of the Ruby Range, West Elk Mountains, Colorado, p. 152. American swallow bug, Oeciaciis vicarius Horvath (Hemiptera: Cimicidae), in Hirundo rustica and Petrochelidon pyrrhonota nests in west central Colorado, p. 345. Andersen, Perron L., and M. John Ramsay, article by, p. 207. Anderson, Stanley H., and Jean F. Cochran, article by, p. 459. Anderson, Stanley H., Wayne A. Hubert, Craig Patterson, and Alan J. Duvall, article by, p. 512. Angell, Raymond P., Richard F. Miller, and Lee E. Eddleman, article by, p. 349. Annotated inventory of invertebrate popula- tions of an alpine lake and stream chain in Colorado, p. 500. Arthur, W. John III, Douglas K. Halford, and A. William Allredge, article by, p. 105. Austin, Dennis D., and Philip J. Urness, arti- cle by, p. 100. Austin, Dennis D., article by, p. 96. Austin, George T. , and Dennis D. Murphy, article by, p. 186. Avian use of scoria rock outcrops, p. 625. Bailey, Reeve M., Walter R. Courtenay, Jr., C. Richard Robins, and James E. Deacon, article by, p. 523. Bee visitors of sweetvetch, Hedysarum bore- ale boreale (Leguminosae), and their pol- len-collecting activities, p. 314. Belk, Mark C. , Edward H. Robey, Jr. , and H. Duane Smith, article by, p. 488. Big sagebrush {Artemisia tridentata vasey- ana ) and longleaf snowberry {Symphoricar- pos oreophilus) plant associations in north- eastern Nevada, p. 117. Black, Andrew H., and Jeffrey H. Black, arti- cle by, p. 344. Black, Jeffrey H., and Andrew H. Black, arti- cle by, p. 344. Blake, Elizabeth A., Robert L. Mathiasen, and Carleton B. Edminster, article by, p. 467. Brotherson, Jack D., article by, p. 322. Brotherson, J. D., and K. P. Price, article by, p. 132. Brotherson, Jack D., and Samuel R. Rush- forth, article by, p. 583. Brotherson, J. D., K. P. Price, and L. O'Rourke, article by, p. 334. Brusven, Merlyn A., William R. Meechan, and John P. Ward, article by, p. 22. Bunting, Stephen C, Stuart D. Smith, and M. Hironaka, article by, p. 299. Burrows of the sagebrush vole {Lemmiscus curtains) in southeastern Idaho, p. 276. Bushnell, John H., Susan Q. Poster, and Bruce M. Wahle, article by, p. 500. Casey, Osborne, Rodger L. Nelson, and William S. Platts, article by, p. 480. Ching, H. L., and R. A. Heckmann, article by, p. 259. Chitaley, Shya, E. M. V. Nambudiri, and William D. Tidwell, article by, p. 527. Cincotta, R. P., D. W. Uresk, and R. M. Hansen, article by, p. 339. Cochran, Jean P., and Stanley H. Anderson, article by, p. 459. Coff'een, M. P., C. L. Pritchett, J. A. Nilsen, and H. D. Smith, article by, p. 231. 661 662 Great Basin Naturalist Vol. 47, No. 4 Coleman, Bruce, Richard A. Heckmann, Lauritz A. Jensen, and Robert G. Warnock, article by, p. 355. Colorado ground beetles (Coleoptera: Cara- bidae) from the Rotger Collection, Univer- sity of Colorado Museum, p. 631. Comparison of habitat attributes at sites of stable and declining long-billed curlew populations, p. 459. Competition for food and space in a het- eromyid community in the Great Basin Desert, p. 2. Consumption of fresh alfalfa hay by mule deer and elk, p. 100. Courtenay, Walter R. , Jr. , C. Richard Robins, Reeve M. Bailey, and James E. Deacon, article by, p. 523. Cox, George W., Christopher G. Gakahu, and Douglas W. Allen, article by, p. 609. Deacon, James E., Paul B. Schumann, and Edward L. Stuenkel, article by, p. 538. Deacon, James E., Walter R. Courtenay, Jr., C. Richard Robins, and Reeve M. Bailey, article by, p. 523. Demography of black-tailed prairie dog popu- lations reoccupying sites treated with ro- denticide, p. 339. Development and longevity of ephemeral and perennial leaves on Artemisia tridentata Nutt. ssp. wyomingensis, p. 227. Diamond Pond, Harney County, Oregon: vegetation history and water table in the eastern Oregon desert, p. 427. Distribution of vertebrates of the Bighorn Canyon National Recreation Area, p. 512. Dobson, Martin L., Clyde L. Pritchett, and Jack W. Sites, Jr., article by, p. 551. Douglas-fir dwarf mistletoe parasitizing Pacific silver fir in northern California, p. 161. Drosophila pseudoobscura (Diptera: Dro- sophilidae) of the Great Basin IV: a release experiment at Bryce Canyon, p. 32. Dry-year grazing and Nebraska sedge {Carex nebraskensis), p. 422. Duvall, Alan J., Stanley H. Anderson, Wayne A. Hubert, and Craig Patterson, article by, p. 512. Eckert, Richard E. Jr., and Paul T. Tueller, article by, p. 117. Ecological comparison of sympatric popula- tions of sand lizards {Cophosaurus texanus and Callisaurus draconoides), p. 175. Eddleman, Lee E., Richard F. Miller, and Raymond F. Angell, article by, p. 349. Edminster, Carleton B., Robert L. Mathi- asen, and Elizabeth A. Blake, article by, p. 467. Effects of artificial shading on distribution and abundance of juvenile chinook salmon {Oncorhynchus tshawytscha), p. 22. Effects of forest fuel smoke on dwarf mistletoe seed germination, p. 652. Effects of land clearing on bordering winter annual populations in the Mohave Desert, p. 234. Effects of logging on habitat quality and feed- ing patterns of Abert squirrels, p. 252. Effects of osmotic potential, potassium chlo- ride, and sodium chloride on germination of greasewood {Sarcobatus vermiculatus), p. 110. Elemental compartmentalization in seeds of Atriplex triangularis and Atriplex conferti- folia, p. 91. Elias, Scott A., article by, p. 631. Estimates of site potential for ponderosa pine based on site index for several southwest- ern habitat types, p. 467. Evaluation of the improvement in sensitivity of nested frequency plots to vegetational change by summation, p. 299. Evans, Howard E., article by, p. 319. Evidence for variability in spawning behavior of interior cutthroat trout in response to environmental uncertainty, p. 480. Farentinos, R. C, Jordan C. Pederson, and Victoria M. Littlefield, article by, p. 252. Field clinic procedures for diagnosing Echi- nococcus gramdosus in dogs, p. 207. Flora of the Orange Cliffs of Utah, p. 287. Foster, Susan Q., John H. Bushnell, and Bruce M. Wahle, article by, p. 500. Freeman, Patricia W., and Cliff A. Lemen, article by, p. 1. Furniss, Malcolm M., and James B. Johnson, article by, p. 375. Gakahu, Christopher G., George W. Cox, and Douglas W. Allen, article by, p. 609. Genetic variation and population structure in the cliff chipmunk, Eutamias dorsalis, in Utah, p. 551. Habitat and community relationships of cliff- rose (Cowania mexicana var. stansburiana) in central Utah, p. 132. Haferkamp, Marshall R., and James T. Romo, article by, p. 110. October 1987 Index 663 Halford, Douglas K., W. John Arthur III, and A. Wilham Allredge, article by, p. 105. Hansen, R. M., R. P. Cincotta, and D. W. Uresk, article by, p. 339. Hartman, Emily L., and Mary Lou Rottman, article by, p. 152. Heckmann, Richard A., Allen K. Kimball, and Jeffery A. Short, article by, p. 13. Heckmann, Richard A., Lauritz A. Jensen, Robert G. Warnock, and Bruce Coleman, article by, p. 355. Heckmann, R. A., and H. L. Ching, article by, p. 259. Helminth parasites of the Wyoming ground squirrel, Spennophilus elegans Kennicott, 1863, p. 103. Herbivorous and parasitic insect guilds associ- ated with Great Basin wildrye {Elymus cinereus) in southern Idaho, p. 644. Hess, W. M., M. A. Khan, and D. J. Weber, article by, p. 91. Hironaka, M., Stuart D. Smith, and Stephen C. Bunting, article by, p. 299. Horner, N. V., G. J. Seiler, G. Zolnerowich, and C. E. Rogers, article by, p. 280. Hubert, Wayne A., Stanley H. Anderson, Craig Patterson, and Alan J. Duvall, article by, p. 512. Hunter, Katherine Bell, Richard Hunter, F. B. Turner, and R. G. Lindberg, article by, p. 234. Hunter, Richard, F. B. Turner, R. G. Lind- berg, and Katherine Bell Hunter, article by, p. 234. Hylesinopsis acacicolens, p. 547. Hylesinopsis secutus, p. 547. Hylociirus atkinsoni, p. 547. Hylocurus crotonis, p. 548. Jacobson, Tracy L. C, and Bruce L. Welch, article by, p. 497. Jensen, James A., article by, p. 592. Jensen, Lauritz A., Richard A. Heckmann, Robert G. Warnock, and Bruce Coleman, article by, p. 355. Johnson, James B., and Malcolm M. Furniss, article by, p. 375. Johnson, James B., Berta A. Youtie, and Michael Stafford, article by, p. 644. Keller, Barry L., and Tim R. MuUican, article by, p. 276. Khan, M. A., D. J. Weber, and W. M. Hess, article by, p. 91. Khan, M. A., N. Sankhla, D. J. Weber, and E. D. McArthur, article by, p. 220. Kimball, Allen K., Richard A. Heckmann, and Jeffery A. Short, article by, p. 13. Knowles, Craig J., article by, p. 202. Knutson, Donald, and Arthur McKee, article by, p. 163. Laven, Richard D., and G. Thomas Zimmer- man, article by, p. 652. Lemen, Cliff A., and Patricia W. Freeman, article by, p. 1. Leptophlebiidae of the southwestern United States and northwestern Mexico (Insecta: Ephemeroptera), p. 283. Lindberg, R. G., Richard Hunter, F. B. Turner, and Katherine Bell Hunter, article by, p. 234. Lindzey, Fredrick G., and Otto O. Oede- koven, article by, p. 638. List of Idaho Scolytidae (Coleoptera) and notes on new records, p. 375. Littlefield, Victoria M., Jordan C. Pederson, and R. C. Farentinos, article by, p. 252. Lizards and turtles of western Chihuahua, p. 383. Loftis, Larry, and Robert L. Mathiasen, arti- cle by, p. 161. Madsen, James H., Jr., and Michael E. Nel- son, article by, p. 239. Maser, Chris, and Zane Maser, article by, p. 308. Maser, Zane, and Chris Maser, article by, p. 308. Maternal care of neonates in the prairie skink, Eumeces septentrionalis, p. 536. Mathiasen, Robert L., and Larry Loftis, arti- cle by, p. 161. Mathiasen, Robert L., Elizabeth A. Blake, and Carleton B. Edminster, article bv, p. 467. McArthur, E. D., M. A. Khan, and N. Sankhla, and D. J. Weber, article by, p. 220. McCallister, Gary, and Thomas Orr, article by, p. 345. McKee, Arthur, and Donald Knutson, article by, p. 163. Medica, Philip A., Donald D. Smith, and Sherburn R. Sanborn, article by, p. 175. Meechan, William R., Merlyn A. Brusven, and John F. Ward, article by, p. 22. Microvelia rasilis Drake in Arizona: a species new to the United States (Heteroptera: Veliidae), p. 660. Miller, Richard F., and Leila M. Shultz, arti- cle by, p. 227. 664 Great Basin Naturalist Vol. 47, No. 4 Miller, Richard F., Lee E. Eddleman, and Raymond F. Angell, article by, p. 349. Monarthrum \a\apensis, p. 548. Mullican, Tim R., and Barry L. Keller, article by, p. 276. Murphy, Dennis D., and George T. Austin, article by, p. 186. Murvosh, Chad M., and Richard K. Allen, article by, p. 283. Nambudiri, E. M. V., William D. Tidwell, and Shya Chitaley, article by, p. 527. Neely, E. E., L. M. Shultz, and J. S. Tuhy, article by, p. 287. Nelson, C. Riley, article by, p. 38. Nelson, Michael E., and James H. Madsen, Jr., article by, p. 239. Nelson, Rodger L., William S. Platts, and Osborne Gasey, article by, p. 480. New brachiosaur material from the Late Jurassic of Utah and Colorado, p. 592 Niche pattern in a Great Basin rodent fauna, p. 488. Nilsen, J. A., G. L. Pritchett, and N. P. Gof- feen, and H. D. Smith, article by, p. 23L Notes on American Sitona (Goleoptera: Gur- culionidae), with three new species, p. 168. Notes on mycophagy in four species of mice in the genus Peromyscus, p. 308. Observations of captive Rocky Mountain mule deer behavior, p. 105. Observations on natural enemies of western spruce budworm {Choristoneura occiden- talis Freeman) (Lepidoptera, Torticidae) in the Rocky Mountain area, p. 319. Observations on the ecology and trophic status of Lake Tahoe (Nevada and Califor- nia, USA) based on the algae from three independent surveys, p. 562. Occurrence of the musk ox, Syinbos cav- ifrons, from southeastern Idaho and com- ments on the genus Bootherium, p. 239. Oedekoven, Otto O., and Fredrick G. Lindzey, article by, p. 638. Orr, Thomas, and Gary McCallister, article by, p. 345. O'Rourke, L., J. D. Brotherson, and K. P. Price, article by, p. 334. Parasites of mottled sculpin, Cottus hairdi Girard, from five locations in Utah and Wasatch counties, Utah, p. 13. Parasites of the bowhead whale, Balaena m|/.s- ticetus, p. 355. Parasites of the cutthroat trout, Salmo clarki, and longnose sucker, Catostornus cato- stomus, from Yellowstone Lake, Wyoming, p. 259. Patterson, Craig, Stanley H. Anderson, Wayne A. Hubert, and Alan J. Duvall, arti- cle by, p. 512. Pederson, Jordan C, R. G. Farentinos, and Victoria M. Littlefield, article by, p. 252. Plant community changes within a mature pinyon-juniper woodland, p. 96. Plant community zonation in response to soil gradients in a saline meadow near Utah Lake, Utah County, Utah, p. 322. Planting depth of Hobble Greek' mountain big sagebrush seed, p. 497. Platts, William S., Rodger L. Nelson, and Osborne Gasey, article by, p. 480. Polhemus, John T., and Milton W. Sander- son, article by, p. 660. Price, K. P., and J. D. Brotherson, article by, p. 132. Price, K. P., J. D. Brotherson, and L. O'Rourke, article by, p. 334. Pritchett, Clyde L., Martin L. Dobson, and Jack W. Sites, Jr., article by, p. 551. Pritchett, C. L., J. A. Nilsen, M. P. GofiFeen, and H. D. Smith, article by, p. 231. Pseiidochramesus ialiscoensis, p. 549. Pseudocrossidium aureum (Bartr.) Zand. (Pottiaceae, Musci) new to Utah, p. 347. Pseudopityophthonis durangoensis, p. 549. Pseiidopityophthoriis xalapae, p. 549. Pygmy rabbits in the Colorado River drainage, p. 231. Ramsay, M. John, and Ferron L. Andersen, article by, p. 207. Ratliff, Raymond D., and Stanley E. Westfall, article by, p. 422. Records of exotic fishes from Idaho and Wyoming, p. 523. Redder, Alan J., Wayne A. Hubert, Craig Patterson, and David Duvall, article by, p. 512. Relationship of western juniper stem con- ducting tissue and basal circumference to leaf area and biomass, p. 349. Reproduction of the prairie skink, Eumeces septentrionalis , in Nebraska, p. 373. Reproductive ecology of black-tailed prairie dogs in Montana, p. 202. Revision of Sahniocarpon harrisii Chitaley & Patil based on new specimens from the Deccan Intertrappean Beds of India, p. 527. October 1987 Index 665 Rickart, Eric A., article by, p. 620. Robber flies of Utah (Diptera: Asilidae), p. 38. Robey, Edward H., Jr., H. Duane Smith, and Mark C. Belk, article by, p. 488. Robins, C. Richard, Walter R. Courtenay, Jr., Reeve M. Bailey, and James E. Deacon, article by, p. 523. Rogers, C. E., G. J. Seiler, G. Zolnerowich, and N. V. Horner, article by, p. 280. Romo, James T. , and Marshall R. Haferkamp, article by, p. 110. Rottman, Mary Lou, and Emily L. Hartman, article by, p. 152. Rumble, Mark A., article by, p. 625. Rushforth, Samuel R., and Jack D. Brother- son, article by, p. 583. Sanborn, Sherburn R., Donald D. Smith, and Philip A. Medica, article by, p. 175. Sanderson, Milton W., and John T. Pol- hemus, article by, p. 660. Sankhla, N., M. A. Khan, D. J. Weber, and E. D. McArthur, article by, p. 220. Schumann, Paul B., James E. Deacon, and Edward L. Stuenkel, article by, p. 538. Seed germination characteristics of Chry- sothamnus nauseosus ssp. viridulus (As- tereae, Asteraceae), p. 220. Seiler, G. J., G. Zolnerowich, N. V. Horner, and C. E. Rogers, article by, p. 280. Sequence of epiphyseal fusion in the Rocky Mountain bighorn sheep, p. 7. Short, JeflFery A., Richard A. Heckmann, and Allen K. Kimball, article by, p. 13. Shults, Larry M., and Nancy L. Stanton, arti- cle by, p. 103. Shultz, Leila M., and Richard F. Miller, arti- cle by, p. 227. Shultz,'L. M., E. E. Neely, and J. S. Tuhy, article by, p. 287. Sites, Jack W., Jr., Martin L Dobson, and Clyde L. Pritchett, article by, p. 551. Sitona alpinensis, p. 170. Sitona bryanti, p. 172. Sitona oregonensis, p. 172. Six new Scolytidae (Coleoptera) from Mexico, p. 547. Small-stone content of Mima mounds of the Columbia Plateau and Rocky Mountain re- gions: implications for mound origin, p. 609. Smith, Donald D., Philip A. Medica, and Sherburn R. Sanborn, article by, p. 175. Smith, H. D., C. L. Pritchett, J. A. Nilsen, and M. P. Coffeen, article by, p. 231. Smith, H. Duane, Edward H. Robey, Jr., and Mark C. Belk, article by, p. 488. Smith, Stuart D., Stephen C. Bunting, and M. Hironaka, article by, p. 299. Smolik, J., and T. Weaver, article by, p. 473. Soil nematodes of northern Rocky Mountain ecosystems: genera and biomasses, p. 473. Somma, Louis A., articles by, p. 373, 536. Spence, John R., article by, p. 347. Spider fauna of selected wild sunflower spe- cies sites in the southwest United States, p. 280. Stackhouse, Mark, and Vincent J. Tepedino, article by, p. 314. Stafford, Michael, BertaA. Youtie, and James B. Johnson, article by, p. 644. Stanton, Nancy L., and Larry M. Shults, arti- cle by, p. 103. Stuenkel, Edward L., James E. Deacon, and Paul B. Schumann, article by, p. 538. Tanner, Vasco M., article by, p. 168. Tanner, Wilmer W., article by, p. 383. Tepedino, Vincent J., and Mark Stackhouse, article by, p. 314. Thermal tolerances and preferences of fishes of the Virgin River system (Utah, Arizona, Nevada), p. 538. Tidwell, William D., E. M. V. Nambudiri, and Shya Chitaley, article by, p. 527. Tueller, Paul T. , and Richard E. Eckert, Jr., article by, p. 117. Tuhy, J. S., L. M. Shultz, and E. E. Neely, article by, p. 287. Turner, F. B., Richard Hunter, R. G. Lind- berg, and Katherine Bell Hunter, article by, p. 234. Turner, Monte E., article by, p. 32. Type specimens of recent mammals in the Utah Museum of Natural History, Univer- sity of Utah, p. 620. Uresk, D. W., R. P. Cincotta, and R. M. Hansen, article by, p. 339. Unless, Philip J., and Dennis D. Austin, arti- cle by, p. 100. VanLandingham, Sam L., article by, p. 562. Wahle, Bruce M., John H. Bushnell, and Su- san Q. Foster, article by, p. 500. Walker, Danny, article by, p. 7. Ward, John F., William R. Meechan, and Merlyn A. Brusven, article by, p. 22. Warnock, Robert G., Richard A. Heckmann, Lauritz A. Jensen, and Bruce Coleman, ar- ticle by, p. 355. Weaver, T. , and J. Smolik, article by, p. 473. 666 Great Basin Naturalist Vol. 47, No. 4 Weber, D. J., M. A. Khan, N. Sankhla, and E. D. McArthur, article by, p. 220. Weber, D. J., M. A. Khan, and W. M. Hess, article by, p. 91. Welch, Bruce L., and Tracy L. C. Jacobson, article by, p. 497. Western painted turtle in Grant County, Ore- gon, p. 344. Westfall, Stanley E., and Raymond D. RatlifF, article by, p. 422. Wigand, Peter Ernest, article by, p. 427. Winter habitat-use patterns of elk, mule deer, and moose in southwestern Wyoming, p. 638. Wood, Stephen L., article by, p. 547. Youtie, BertaA., Michael Stafford, and James B. Johnson, article by, p. 644. Zimmerman, G. Thomas, and Richard D. Laven, article by, p. 652. Zolnerowich, G., G. J. Seiler, N. V. Horner, and C. E. Rogers, article by, p. 280. Zonation patterns in the vascular plant com- munities of Benton Hot Springs, Mono County, California, p. 583. Zoogeography of Great Basin butterflies: pat- terns of distribution and differentiation, p. 186. NOTICE TO CONTRIBUTORS Manuscripts intended for publication in the Great Basin Naturalist or Great Basin Natural- ist Memoirs must meet the criteria outhned in paragraph one on the inside front cover. The manuscripts should be sent to Stephen L. Wood, Editor, Great Basin Naturalist, 290 Life Science Museum, Brigham Young University, Provo, Utah "84602. Three copies of the manuscript are required. They should be typewritten, double-spaced throughout on one side of the paper, with margins of at least one inch on all sides. Use a recent issue of either journal as a format, and the Council of Biology Editors Style Manual, Fifth Edition (AIBS 1983) in preparing the manuscript. An abstract, about 3 percent as long as the text, but not exceeding 200 words, written in accordance with Biological Abstracts guidelines, should precede the introductory paragraph of each article. Authors may reduce their typesetting costs substantially by sending a copy of their article on a 5.25-inch floppy disk prepared with WordPerfect software in addition to three copies of the manuscript. Illustrations and Tables. All illustrations and tables should be made with a view toward having them appear within the limits of the printed page. 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No. 2 Intermountain biogeography: a symposium. By K. T. Harper, J. L. Reveal et al. $15. No. 3 The endangered species: a symposium. $6. No. 4 Soil-plant-animal relationships bearing on revegetation and land reclamation in Ne- vada deserts. $6. No. 5 Utah Lake monograph. $8. No. 6 The bark and ambrosia beetles of North and Central America (Coleoptera: Scolytidae), a taxonomic monograph. $60. No. 7 Biology of desert rodents. $8. No. 8 The black-footed ferret. $10. No. 9 A Utah flora. By Stanley L. Welsh $40. No. 10 A reclassification of the genera of Scolytidae (Coleoptera). By Stephen L. Wood. $10. TABLE OF CONTENTS Records of exotic fishes from Idaho and Wyoming. Walter R. Courtenay, Jr., C. Richard Robins, Reeve M. Bailey, and James E. Deacon 523 Revision oi Sahniocarpon harrisii Chitaley & Patil based on new specimens from the Deccan Intertrappean Beds of India. E. M. V. Nambudiri, William D. Tidwell, and Shya Chitaley 527 Maternal care of neonates in the prairie skink, Eumeces septentrionalis. Louis A. Somma ^'^^ Thermal tolerances and preferences of fishes of the Virgin River system (Utah, Arizona Nevada). Tames E. Deacon, Paul B. Schumann, and Edward L. Stuenkel. 538 • Six new Scolytidae (Coleoptera) from Mexico. Stephen L. Wood 547 Genetic variation and population structure in the cliff chipmunk, Eutamias dorsalis, in the Great Basin of western Utah. Martin L. Dobson, Clyde L. Pritchett, and Jack W. Sites, Jr 551 Observations on the ecology and trophic status of Lake Tahoe (Nevada and California, USA) based on the algae from three independent surveys (1965-1985). Sam L. VanLandingham 562 Zonation patterns in the vascular plant communities of Benton Hot Springs, Mono County, California. Jack D. Brotherson and Samuel D. Rushforth 583 New brachiosaur material from the Late Jurassic of Utah and Colorado. James A. Jensen 592 Small-stone content of Mima mounds of the Columbia Plateau and Rocky Mountain regions: implications for mound origin. George W. Cox, Christopher G. Gakahu, and Douglas W. Allen 609 Type specimens of recent mammals in the Utah Museum of Natural History, Univer- sity of Utah. Eric A. Rickart 620 Avian use of scoria rock outcrops. Mark A. Rumble 625 Colorado ground beetles (Coleoptera: Carabidae) from the Rotger Collection, Univer- sity of Colorado Museum. Scott A. Elias 631 Winter habitat-use patterns of elk, mule deer, and moose in southwestern Wyoming. Olin O. Oedekoven and Fredrick G. Lindzey 638 Herbivorous and parasitic insect guilds associated with Great Basin wildrye {Elymiis cinereus) in southern Idaho. Berta A. Youtie, Michael Stafford, and James B. Johnson 644 Effects of forest fuel smoke on dwarf mistletoe seed germination. G. Thomas Zimmer- man and Richard D. Laven 652 Microvelia rasilis Drake in Arizona: a species new to the United States (Heteroptera: Veliidae). John T. Polhemus and Milton W. Sanderson 660 Index 661 3 2044 072 231 210