ISSN 0038-3872 SOMME RN CALIFORNIA ACADEMY OF SCIENCES LETIN Volume 89 Number 1 BCAS-A89(1) 1-48 (1990) APRIL 1990 Southern California Academy of Sciences Founded 6 November 1891, incorporated 17 May 1907 © Southern California Academy of Sciences, 1990 OFFICERS Camm C. Swift, President June Lindstedt Siva, Vice-President Hans M. Bozler, Secretary Takashi Hoshizaki, Treasurer Jon E. Keeley, Technical Editor Gretchen Sibley, Managing Editor BOARD OF DIRECTORS 1988-1990 1989-1991 1990-1992 Sarah B. George Takashi Hoshizaki Jack W. Anderson Margaret C. Jefferson George T. Jefferson Hans M. Bozler Susanne Lawrenz-Miller David L. Soltz Theodore J. Crovello John D. Soule Camm C. Swift Peter L. Haaker Gloria J. Takahashi Robert G. Zahary June L. Siva Membership 1s open to scholars in the fields of natural and social sciences, and to any person interested in the advancement of science. 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Date of this issue 8 May 1990 | THIS PUBLICATION IS PRINTED ON ACID-FREE PAPER. | Bull. Southern California Acad. Sci. 89(1), 1990, pp. 1-9 © Southern California Academy of Sciences, 1990 Late Quaternary Nonmarine Mollusca from Kokoweef Cave, Ivanpah Mountains, California Barry Roth! and Robert E. Reynolds? 1Department of Invertebrate Zoology, Santa Barbara Museum of Natural History, Santa Barbara, California 93105 *Department of Earth Sciences, San Bernardino County Museum, 2024 Orange Tree Lane, Redlands, California 92373 Abstract. —An assemblage of one freshwater and seven terrestrial mollusk species was collected in Kokoweef Cave, at 1720 m in the Ivanpah Mountains, San Bernardino County, California, associated with vertebrate remains of Ranchola- brean (late Pleistocene) age. All but one of the molluscan taxa are extant. Most of the species indicate an environment like that of modern pine and fir forest now found at elevations above 2200 m in the Spring Range, Nevada. There is also a xerophilic element characteristic of the modern Lower Sonoran Zone. In the time interval represented by the fossils, the pine and fir forest zone probably extended 500-1000 m lower than at present. A molluscan assemblage consisting of one freshwater and seven terrestrial species (Table 1) was collected in Kokoweef Cave, Ivanpah Mountains (NE1/4 NW1/4 sec. 4, T. 15 N, R. 14 E, San Bernardino Base and Meridian; elev. 1720 m), San Bernardino County, California, by parties from the San Bernardino County Mu- seum (Loc. SBCM 1-11-13). They range from the 18.5 ft (5.6 m) to the 37-38 ft (11.3-11.6 m) datum of excavation and were associated with abundant vertebrate remains indicating a Rancholabrean (late Pleistocene) age. Vertebrate fauna and flora from the cave that are extinct or locally absent include Equus sp., cf. E. conversidens; Camelops sp.; Hemiauchenia sp.; Euceratherium? sp.; Canis sp., cf. C. dirus; Marmota flaviventris; Ochotona princeps; Spermophilus townsendi; Spermophilus lateralis; Tamias minimus; Tamias palmeri;,; Lagurus sp.; Gymnogyps sp.; and Celtis sp. (Goodwin 1986; Reynolds 1972, San Bernar- dino County Museum collections). The reptile fauna has been reviewed by Norell (1986). A radiocarbon age of 9830 + 150 yr BP has been obtained on charcoal from the 20.5 ft (6.2 m) datum (A. Sarna-Wojcicki, in /itt. to Reynolds, June 26, 1985). At present the vegetation in the environs of Kokoweef cave is juniper scrub, including Ephedra spp., Yucca baccata, and Yucca schidigera. There are no pub- lished records of the modern mollusk faunas of the lvanpah Mountains or adjacent Mescal Range. In the better-studied Spring Range, Clark County, Nevada, 40- 110 km to the north, land snails are largely restricted to the coniferous forest above 2200 m, with a few species ranging down to springs in pinyon-juniper woodland at 1900 m (Pratt 1976). In analyzing a fossil assemblage, it is necessary to determine whether the con- stituent taxa could all have lived in the same habitat and whether they were 1 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES ‘ZuNJOS UI poysInsunNsip you g'ds ‘u ‘4 pure Yyjasoydojoad ‘A ‘O1/ST] 91dtues ut juasaid YIUO]/VA [R1OL See ek ee ee ee ee 0/t C/T 0/1 O/T 1/9 t/vl £/0 1/0 LIGI ‘AIQS|Id IPUDY X1/AYO%MO O/E 0/1 0/1 (Opg] ‘Aouulg) wou “yWone YyNosnUIL DIIDMD]T 0/¢ /71 b/Ob O/L 1/Z 998] “UOAIL, 19qD8 “g “JO “ds DaUIIINS 0/9 0/9 0/8 * 0/L8 0/SI ds ‘u ‘pluojjDA 0/SI 0/11 O/L 0/C * ST/T9S 0/CS 0/1 Z6RI ‘PAIS Yjjasoydojodo pIUo]]vA 0/7 0/1 0/¢ /€ LI/TI €8/€E1 6/7 (1881 ‘Avouy) sagay vjjidnd 0/1 O/L 6£/187Z 0/7 (0681 ‘AIQSTId) DJ/a2vapsoYy ppionjjad DIGOIOAISDL) 0/7 (SSQ] ‘p[noy) vajoid DIUOAL epodo.sey a ES ee es eee ee eee ee oe ee MS. 8E€-LE MS,SE-bE MS,0€-67T MS,67-87 =MN.PC-ET MN.£C-CC MN, IC MN.S'81 sa1adg 90UdIINIIO eee MMnmOMOSOo SIUDWIELJ,, POANPISUOS oe saddId JOYIO [Te {(o[]duues OY} UT SNOJILUNU OIOUW ST IDADYOIYM) ainqiode ynpe oy} 10 xadv oy) 194119 BUTUTE]UOD [JOYS JO sdaId B 10 [JOYS 9[OYM vB SB PoUyop SI _uowtoods,, y ‘s}uow sey Jo Joquinu/susutoads Jo Joquinu oie PIeC ‘umnasnyy A1uN0D OurIpieUlog URS ‘UoWTIEdoq Ss0U9TNS Ye IY) UI poysodop oe saduieg “OAR JoOMOYOY Wo sysn][ou! suleUrUOU dUdd0}SIDJ[q WET “] WGeL QUATERNARY MOLLUSCA FROM KOKOWEEF CAVE 3 preserved in the environment in which they lived. California has no truly trog- lobitic land mollusks (A. G. Smith 1957), although some may at times find the right conditions of moisture, shelter, and food availability near the mouths of caves. Except as discussed below, the mollusks in Kokoweef Cave probably washed or drifted in from habitats in the near vicinity. Like many of the bones in the deposit, some may have been brought in by wood rats (Neotoma). Tryonia protea is a freshwater snail; the others are terrestrial (or in the case of Succinea, perhaps marginally aquatic) species. In addition, 7. protea and Gastrocopta pellucida hordeacella are xerophilic forms, while the other species could readily represent a modern biocoenosis that would occur under cooler and moister conditions than those now present in eastern San Bernardino County at the elevation of Kokoweef Cave. Modern Occurrence of Component Taxa All taxa identified to species are extant; Vallonia n. sp.? may be extinct. Tryonia protea today occurs in scattered populations from western Utah to southeastern California and adjacent Baja California, in streams flowing out of thermal springs (Taylor 1981), but was formerly abundant in pluvial lakes, including Lake Cahuilla (Stearns 1883; Bowersox 1974). Typical modern occurrences would include those in limnocrenes and their outflow streams at Ash Meadows, Nye County, Nevada, and in Death Valley, California (W. L. Pratt, in /itt. to Roth, 1986) in the Lower Sonoran Life Zone. Gastrocopta pellucida hordeacella is widespread from the southern United States to Central America, reaching west to Snow Creek and Palm canyons, San Jacinto Mountains, Riverside County, California (Berry 1922; Roth, unpublished data). Its broad geographic range implies considerable eurytopy, but little ecological information has been published. In Arizona and New Mexico it is common in the Lower and Upper Sonoran life zones from elevations of 300 to 2000 m (Bequaert and Miller 1973; Ashbaugh and Metcalf 1986). The San Jacinto Moun- tains occurrences are also in the Lower Sonoran Zone. The species occurs in spring-fed marshes in Clark County, Nevada, but only below 700 m (W. L. Pratt, in litt. to Roth, 1986). In New Mexico it is ““common in leaf litter under shrubs along floodplains and in lower canyons in mountainous areas” (Ashbaugh and Metcalf 1986:10). Pupilla hebes is a characteristic Rocky Mountain and Great Basin species. Its present distribution extends from Montana, at an elevation of 1200 m, to northern Chihuahua at 2100 m and Baja California at 2700-2800 m (Miller 1981). In Arizona it ranges from 1500 to 3400 m (Bequaert and Miller 1973). Typical habitats range from mixed aspen-conifer woodland, on the mesic extreme, to the more xeric pine-locust or oak-juniper woodland (LaRochelle 1986). In the central Great Basin, Pratt (1979b) reports it as sporadic in rockslides and burrowing along rock ledges. The species has not been reported previously from San Bernardino County, California, but it has been collected at the following California localities: 7.2 km southeast of Markleeville, Alpine County, by W. L. Pratt, June 1978; along Lee Vining Creek, West Walker River at U.S. Highway 395, and Silver Lake, all in Mono County, by W. B. Miller, July 1985; and at 3000 m elevation in the Ancient Bristlecone Pine Forest, White Mountains, Mono and Inyo Coun- ties, by W. B. Miller, 1985. The S. S. Berry molluscan collection at the Santa 4 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES Barbara Museum of Natural History contains one lot labeled Mono County, March 1940. Vallonia cyclophorella ranges from the Dakotas to Arizona and southeastern California. In Arizona it ranges from 1400-3000 m, in the Transition, Canadian, and Hudsonian life zones (Bequaert and Miller 1973); in New Mexico, from 1950- 3255 m in wooded canyons and montane forests (Ashbaugh and Metcalf 1986). In southern California it occurs over a similar range of altitudes and is found in forest litter and under logs or bark on the ground. In the Spring Range it is restricted to 1900 m and above (Pratt 1976). Vallonia cyclophorella is one of the most widely distributed species in the central Great Basin (Pratt 1979), occurring in all habitats supporting snails. The eurytopy limits its usefulness as an indicator of paleoen- vironments. In most of the samples, another form of Va//onia is present, usually in smaller numbers than Vallonia cyclophorella. It is larger than V. cyclophorella (to 3 mm in diameter), with four whorls. The body whorl expands less rapidly than in V. cyclophorella and turns down less sharply behind the aperture; the peristome is only weakly developed into a flange. This form (cited as Vallonia n. sp.?) may be extinct; it cannot be identified with any species known to be living in North America. We draw no paleoenvironmental inferences from it at this time. Empty shells of the family Succineidae, such as Succinea sp., cf. S. gabbi reported here, cannot usually be identified to species. In general, however, succineids are snails of moist habitats, such as the edges of marshy lakes or moist mountain meadows. Succinea gabbi is known from the Great Basin drainage of California and from eastern Oregon and Washington. Hawaiia minuscula is a eurytopic and widely distributed species, at present ranging from Alaska and Newfoundland to Central America. Records of the species from the arid southwest, however, pertain to one or more anatomically distinct, unnamed species (Pratt 1979, and unpublished report to Desert Research Institute, University of Nevada). In southern Nevada, Hawaiia minuscula auctt. occurs in damp, grassy areas around springs and along permanent streams in the lower montane zone (Pratt, unpublished). In Arizona it ranges from 800 to 2600 m (Bequaert and Miller 1973). In western Texas and New Mexico, it occurs on floodplains, in mesic, forested montane habitats, and in relatively xeric habitats in low mountains and foothills (Ashbaugh and Metcalf 1986). Oreohelix handi is restricted at present to the Spring Range, Nevada, at ele- vations of 2700-2900 m on Charleston Peak and at 2300 m on Potosi Mountain (Pilsbry 1939; Pratt 1976). These localities are in the zones of White Fir, Limber Pine, and the upper range of Yellow Pine (Mehringer 1964), equivalent to the Transition Zone and the lower part of the Canadian Zone. W. L. Pratt (in litt. to Roth, 1986) reports that O. handi is found “only in the pine-fir conifer forest, but is apt to turn up in any little patch of the habitat where there is a sheltered slope or some ledges, even though the surrounding slopes are in pinyon-juniper woodland. It is generally found under small rocks, logs and similar cover.” A similar but larger-shelled species, Oreohelix jaegeri Berry, 1931 (not a sub- species of O. handi as it was formerly regarded [Pratt 1979a]), occurs at 2300 m on Charleston Peak, but the Kokoweef Cave specimens more closely resemble O. handi. This is the first record of O. handi outside of Nevada. The occurrence in Kokoweef Cave is 60 km south of its present range. The only Recent occurrence QUATERNARY MOLLUSCA FROM KOKOWEEF CAVE 5 of Oreohelix in California is that of Oreohelix californica Berry, 1931, on Clark Mountain, 15 km northwest of the Ivanpah Mountains, among limestone frag- ments and fir needles in rockslides at an elevation of 2100 m. Interpretation of the Assemblage Oreohelix handi is the most stenotopic species in the assemblage and therefore the most informative. It is also the most critical indicator of montane-type con- ditions. Its presence suggests that conditions now characteristic of pine and fir forest extended between 500 and 1100 m lower than their present elevation in neighboring ranges of southwest Nevada. The occurrences of Pupilla hebes, Ha- waiia minuscula auctt., and Vallonia cyclophorella are consistent with this inter- pretation, although the modern ranges of all three extend to lower altitudes else- where. All probably lived in the immediate vicinity of the cave, in relatively mesic, rocky sites. In a pine or fir forest setting, Succinea would be expected along the edges of low-gradient streams or in moist meadows. Gastrocopta pellucida hordeacella probably occupied relatively xeric sites near- by; less likely, it may have been passively transported from a lower vegetation zone. It may have been an inhabitant of a biotope not now represented in the arid southwest—exposed grassy slopes, its suggested modern habitat in the High Plains (Franzen and Leonard 1947; Taylor 1960). The association of Gastrocopta pellucida hordeacella, Pupilla hebes, Hawaiia minuscula auctt., and Vallonia cyclophorella also occurs at Pleistocene sites in San Pedro Valley, Arizona, associated with mammoth remains 10,000—11,000 yr old (Bequaert and Miller 1973). The ecological amplitude of G. p. hordeacella may have overlapped those of P. hebes and V. cyclophorella during late Pleistocene times of greater moisture availability and less extreme summer temperatures. Floristic associations without modern analogues occur in late Pleistocene packrat middens in the Southwest (Ven Devender and Spaulding 1979), and owe their existence to the individualistic response of plant species to climatic change. Tryonia protea is probably best interpreted as indicating a shallow pluvial lake outside the I[vanpah Mountains. Alternatively, it might have lived in the outflow of a thermal spring within the range itself, although no such spring is known. Pluvial lakes existed both east and west of the cave site (Hewett 1956; Reynolds and Jefferson 1971), contemporaneous with maximum late Pleistocene extension of woodland across the eastern Mojave Desert (Mehringer 1967: fig. 38). Their existence 1s compatible with the conditions that would depress the elevation of vegetation zones. Searles Lake rose to its maximum height 10,000—11,000 yr BP (G. I. Smith 1968). The bones of cyprinid fishes also occur in the Kokoweef Cave deposit. Tryonia protea may have been in the stomachs of fish not indigenous to the cave. Pupfish (Cyprinodontidae) and stickleback (Gasterosteidae) have been named as possible predators on other species of 7ryonia (Kellogg 1980). Many species of shore and wading birds also include small mollusks in their diets. Discussion Numerous paleobotanical studies have indicated that during late Pleistocene (Wisconsinan) time, vegetation zones in the Mojave Desert and southern Nevada were as much as 1000 m lower in elevation than they are now (e.g., Mehringer 1966; Wells and Berger 1967; Van Devender 1977). Mammals from a cave in the 6 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES Mormon Mountains, Nevada, suggest that pine and fir floras were at least 600- 900 m lower in elevation about 10,000 yr BP (Jefferson 1982). The upward shift of vegetation zones to their modern altitudes is mainly the result of climatic warming beginning in the “early Holocene xeric woodland period,’’ 8000-1 1,000 yr BP (Van Devender and Spaulding 1979). At the same time that vegetation zones were lower, the ranges of many mammals and plants extended farther south than they do now (Van Devender and Spaulding 1979: Jefferson 1982). The southernmost present occurrence of Oreohelix handi is approximately 60 km north of its late Pleistocene occurrence in Kokoweef Cave. With the possible exception of Succinea sp., cf. S. gabbi, however, the other extant mollusks are within their modern geographic ranges. Two geographically nearby fossil assemblages, at Valley Wells and Tule Springs, contrast significantly to the Kokoweef Cave assemblage (Table 2). Although these deposits are not precisely correlated, the differences in molluscan composition are explicable in terms of setting, with the Kokoweef Cave site representing up- lands, and the other two sites lowland basins with more or less perennial bodies of water. Taylor (1967) described late Pleistocene mollusks from the Tule Springs site, near Las Vegas, Nevada. The fossil pollen record form Tule Springs indicates that before about 12,000 yr BP the present low-elevation desert supported vegetation types ranging from higher-elevation desert to yellow pine parkland (Mehringer 1964, 1967); at their maximum depression, vegetation zones were 1000-1200 m lower than at present. At least nineteen freshwater species, both bivalves and gastropods, are present, indicating a complex aquatic environment. Although the eurytopic Vallonia cyclophoreila and Hawaiia minuscula auctt. are present, the land mollusks represent a marshy-ground association quite different from the Kokoweef Cave assemblage. Vertigo berryi, for instance, has been found living in marshes along the Muddy River, Clark County, Nevada (Pratt 1979). Gastrocopta tappaniana occurs among moist leaves or under logs in moist grass near seepages (Taylor 1960) and on shaded slopes near streams (Franzen and Leonard 1947) in the High Plains. Both V. berryi and G. tappaniana are found in moist areas around springs in pinyon-juniper woodland in the lower elevations of the spring Range (W. L. Pratt, in litt. to Roth, 1986). Although the Tule Springs deposit was formed over a considerable time interval and the lowest levels may be pre-Wisconsinan, a specific assemblage of species spans the entire time represented by the fossil- iferous strata and indicates the presence of small, shallow creeks or the marshy area of a seepage (Taylor 1967). Hewett (1956) reported an assemblage of freshwater and land mollusks from Quaternary lacustrine beds near Valley Wells, San Bernardino County, 20 km west of the Ivanpah Mountains (Table 2). Mammals of Late Pleistocene age have been recovered from the deposit (Reynolds and Jefferson 1971). Both the strati- graphic setting and the fauna indicate deposition in a wet lowland basin. Tuff from Valley Wells lacustrine sediments north of Cima Dome are chemically correlated with ash beds elsewhere in the western states dated at 2 million and 0.6 million yr BP (A. Sarna-Wojcicki, in litt. to Reynolds, 1985), indicating a pre- Wisconsinan age. Jefferson (1982) has cautioned against attempting to use simple elevational displacement of floristic elements to infer the age of a fossil assemblage, since QUATERNARY MOLLUSCA FROM KOKOWEEF CAVE 7 Table 2. Comparison of Kokoweef Cave mollusks with terrestrial mollusks from late Pleistocene assemblages from Valley Wells, California, and Tule Springs, Nevada, and Recent native land mollusk fauna of Spring Range, Nevada. Freshwater components of fossil assemblages summarized. Occurrence Kokoweef ‘Valley Tule Spring Cave Wells Springs Range (this (Hewett, (Taylor, (Pratt, Species report) 1956) 1967) 1976') Terrestrial Gastrocopta pellucida hordeacella (Pilsbry) x — — Gastrocopta tappaniana (C. B. Adams) — — > Pupilla blandi charlestonensis Pilsbry — — — Pupilla hebes (Ancey) > — Pupilla, n. sp. — x = Pupilla, sp. indet. — — x Vertigo berryi Pilsbry _— x x Vertigo gouldii (Binney) — — — Vertigo modesta ingersolli Cockerell — Vertigo sp. indet. — Vallonia cyclophorella Sterki x Vallonia gracilicosta Reinhardt _ Vallonia, n. sp.? x — — Discus cronkhitei (Newcomb) — — — Oxyloma sp. — _ x Catinella stretchiana (Bland) — — — Succinea sp., cf. S. gabbi Tryon XxX _ — Succinea avara auctt., non Say — x — cf. Succinea, 2 spp. — — > Euconulus fulvus (Miller) — — — Vitrina pellucida (Miller) Hawaiia minuscula auctt., non Binney Deroceras sp., cf. D. laeve (Miiller) — Oreohelix handi Pilsbry x — _ Oreohelix jaegeri Berry — _ - | | xx | x x | x1 x1 | wT KKK OI ~~ | | | x xx KKK XM | Freshwater (Summary) Tryonia protea (Gould) xX — _ Other Hydrobiidae — — 2 spp. Valvatidae — — 1 sp. Lymnaeidae — 2 spp. 5 spp. Ancylidae — — 1 sp. Planorbidae — 1 sp. 4 spp. Physidae — — 1 sp. Sphaeriidae (Bivalvia) — 1 sp. 5 spp. ' With additions from Pratt, in /itt., 1986. plant species tend to respond to climate changes individualistically rather than as communities (Van Devender and Mead 1976). The caveat may be underscored for mollusks as well, since microhabitat conditions rather than the taxonomic composition of the flora determine their local distribution. Moreover, both land and freshwater mollusks are well known for tending toward relict distributions, which, if not recognized as such, may obscure, rather than cleanly reflect, the broad climatic trend at a given time. 8 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES Acknowledgments Weare grateful to P. B. LaRochelle, W. B. Miller, and W. L. Pratt for comments on various parts of the manuscript and for permission to cite unpublished data from their own studies. M. G. Kellogg suggested to Roth the possibility that Tryonia protea was introduced to the deposit in stomachs of fish transported to the cave by birds. Literature Cited Ashbaugh, K. M., and A. L. Metcalf. 1986. Fossil molluscan faunas from four spring-related deposits in the northern Chihuahuan Desert, southern New Mexico and westermost Texas. New Mexico Bur. Mines Miner. Res. Circ. 200. 28 pp. Bequaert, J. C., and W. B. Miller. 1973. The mollusks of the arid southwest. Univ. Arizona Press, Xvi + 271 pp. Berry, S.S. 1922. Notes on the mollusks of the Colorado Desert—I. Proc. Acad. Natur. Sci. Phila- delphia, 74:69-100. Bowersox, J. R. 1974. Paleoecology of upper Lake Cahuilla, California. Geol. Soc. America Abst. Prog., 6:146. Franzen, D. S., and A. B. Leonard. 1947. Fossil and living Pupillidae (Gastropoda=Pulmonata) in Kansas. Univ. Kansas Sci. Bull., 31:311-411. Goodwin, H. T. 1986. Late Pleistocene sciurids from Kokoweef Cave. Masters thesis, Dep. Biology, Loma Linda Univ. 49 pp. Hewett, D. F. 1956. Geology and mineral resources of the Ivanpah Quadrangle, California and Nevada. U.S. Geol. Surv. Prof. Pap. 257. 172 pp. Jefferson, G. T. 1982. Late Pleistocene vertebrates from a Mormon Mountain cave in southern Nevada. Bull. South. California Acad. Sci., 81:121-127. Kellogg, M. G. 1980. Status of the California brackishwater snail, Tryonia imitator, in central California. California Dep. Fish and Game Inl. Fish. End. Spec. Prog. Spec. Publ. 80-3. 23 pp. LaRochelle, P. B. 1986. Sinistrality in Pupilla (Pulmonata: Pupillidae): geographic distribution and reproductive isolation from dextral conspecifics. West. Soc. Malacol. Annu. Rep., 18:24. Mehringer, P. J., Jr. 1964. Late Pleistocene vegetation in the Mojave Desert of southern Nevada. Univ. Arizona Geochronol. Lab. Int. Res. Rep. 6. 30 pp. . 1966. Some notes on the late Quaternary biogeography of the Mohave Desert. Univ. Arizona Geochronol. Lab. Int. Res. Rep. 11. 17 pp. . 1967. Pollen analysis of the Tule Springs site. Pp. 129-200 in Pleistocene studies in southern Nevada. (H. M. Wormington and D. Ellis, eds.), Nevada State Mus. Anthropol. Pap. 13. Miller, W. B. 1981. Helminthoglypta reederi spec. nov. (Gastropoda: Pulmonata: Helminthoglyp- tidae), from Baja California, Mexico. Veliger, 24:46-48. Norell, M. A. 1986. Late Pleistocene lizards from Kokoweef Cave, San Bernardino County, Cali- fornia. Copeia, 1986:244—-246. Pilsbry, H. A. 1939. Land Mollusca of North America (north of Mexico). Acad. Natur. Sci. Phila- delphia Monogr. 3, 1(1):1-573. Pratt, W. L. 1976. Land snails of the Spring Mountains, Clark County, Nevada—a preliminary survey. West. Soc. Malacol. Annu. Rep., 9:46. —. 1979a. A comparative study of two sympatric, closely related Oreohelix species of the O. hemphilli group. Bull. Amer. Malacol. Union, 1978:64. . 1979b. A preliminary report on the land snails of the central Great Basin. West. Soc. Malacol. Annu. Rep., 11:21-25. Reynolds, R. E. 1972. A preliminary discussion of fossiliferous sediments in Kokoweef Cave, San Bernardino County, California. Ms prepared for Concave Mining Corporation, on file in Dep. Earth Sci., San Bernardino Co. Mus., Redlands. —., and G. T. Jefferson. 1971. Late Pleistocene vertebrates from Valley Wells, Mojave Desert, California. Geol. Soc. America Abst. Prog., 3:183. Smith, A. G. 1957. Snails from California caves. Proc. California Acad. Sci., (4)29:21-46. Smith, G. I. 1968. Late Quaternary geologic and climatic history of Searles Lake, southwestern QUATERNARY MOLLUSCA FROM KOKOWEEF CAVE 9 California. Pp. 293-310 in Means of correlation of Quaternary successions. (R. B. Morrison and H. E. Wright, eds.), Univ. Utah Press. Stearns, R. E. C. 1883. On the shells of the Colorado Desert and the region farther east. Amer. Natur., 17:1014-1020. Taylor, D. W. 1960. Late Cenozoic molluscan faunas from the High Plains. U.S. Geol. Surv. Prof. Pap. 337. 94 pp. 1967. Late Pleistocene molluscan shells from the Tule Springs area. Pp. 395-399 in Pleis- tocene studies in southern Nevada. (H. M. Wormington and D. Ellis, eds.), Nevada State Mus. Anthropol. Pap. 13. . 1981. Freshwater mollusks of California: a distributional checklist. California Fish and Game, 67:140-163. Van Devender, T. R. 1977. Holocene woodlands in the southwestern deserts. Science, 198:189-192. , and J. I. Mead. 1976. Late Pleistocene and modern plant communities of Shinumo Creek and Peach Springs Wash, lower Grand Canyon, Arizona. Jour. Arizona Acad. Sci., 11:16—22. , and W. G. Spaulding. 1979. Development of vegetation and climate in the southwestern United States. Science, 204:701-710. Wells, P. V., and R. Berger. 1967. Late Pleistocene history of coniferous woodland in the Mojave Desert. Science, 155:1640-1647. Accepted for publication 28 November 1988. Bull. Southern California Acad. Sci. 89(1), 1990, pp. 10-18 © Southern California Academy of Sciences, 1990 Movement and Habitat Selection in Tagged Rock Crabs (Cancer antennarius) in Intertidal Channels at James V. Fitzgerald Marine Life Refuge, California Robert T. Breen! and Mary K. Wicksten? 'James V. Fitzgerald Marine Life Refuge, P.O. Box 451, Moss Beach, California 94038 ?Department of Biology, Texas A&M University, College Station, Texas 77843 Abstract. —From November 1987 to February 1989, 387 rock crabs (Cancer an- tennarius) were tagged in three intertidal channels at James V. Fitzgerald Marine Life Refuge. Searches for crabs were conducted in the channels during low tides at least monthly. Seventy-nine crabs were resighted alive, 70 of these within one month of tagging. The other nine were resighted at two to nine months after tagging. Seven were resighted more than once. All were resighted in the channels in which they were tagged. Twelve were found dead, all within a short distance of the channels. Tagged C. antennarius measured 71-133 mm in carapace width. The sex ratio was skewed toward females, particularly in spring and summer, but few ovigerous females were found. Eighty-two crabs (21%) were missing or regenerating ap- pendages, six had cracks or holes in the carapace, and twenty-four were encrusted with coralline algae or barnacles. Only one crab was resighted after healing from a previously observed injury. No tagged crab molted during the study period. The crabs seem to use the channels in moving between the intertidal zone and adjacent subtidal areas. Shelter is important to the crabs, which rarely move during low tides. Rock crabs (Cancer antennarius) are among the largest intertidal crabs in central California. Although not sufficiently common to support a major fishery, they are taken at times by commercial fishermen, divers and sport fishermen. They are important predators on shelled mollusks and small crustaceans, which they crush with their powerful chelae (Garth and Abbott 1980). Studies on size and seasonal abundance of adult and juvenile C. antennarius were conducted in intertidal channels at James V. Fitzgerald Marine Life Refuge (also known as James V. Fitzgerald Marine Life Reserve), San Mateo County, California (Fig. 1) during 1985 and 1986 (Breen and Wicksten 1988). The crabs were consistently found in the channels, but relative abundance was lowest after severe winter storms. Male to female sex ratio was 1.6:1. Juveniles were most abundant from late summer through the fall. Individual crabs were recognizable by characteristic injuries, scars, and fouling organisms, but only rarely was the same recognizable individual crab seen during the monthly observations in the channels. To find out more on the movements, size and sex ratio of the crabs, a tagging 10 MOVEMENT AND HABITAT SELECTION IN ROCK CRABS 11 STATE HIGHWAY 1: \)y Montara Light Station \ 1) SAN 1 adie FRANCISCO °:: | Rocky Lagoon \\ SS \ Channel and Surf Grass Flats}\e South Moss BeachRX} NR 122°30'Wo PRINCETON Pillar Point Harbor Fig. 1. Map of study area. (The Refuge also is called James V. Fitzgerald Marine Life Reserve on many maps). study was conducted from November 1987 to February 1989. The objectives were to track movements of the crabs in the intertidal zone, examine habitat preference, and document sex ratios, sizes, seasonal abundance, and crab condition (injuries and fouling). The results provide information on free-ranging crabs in their natural habitat in the intertidal zone. Materials and Methods From 19 November 1987 to 16 February 1989, 387 rock crabs were tagged in three intertidal channels in the flat shale reef at the Refuge (Fig. 1). Each channel varied in width, but was bordered by the shale reef which rises at least 0.3 m above the level of each channel. All of the channels were submerged during tides of 0.8 m or greater. The first channel (““Rocky Lagoon’’) was broad (up to 20 m wide) and covered with movable rocks and boulders. A 50 m transect was estab- lished in the shoreward half of the area of the channel. The second transect (“Channel and Surf Grass Flats’’) was 50 m long by 5 m wide, and consisted of a rock-covered surge channel with a direct connection to the ocean during all tidal 12 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES phases. This channel extended higher in the intertidal zone (to the 0.8 to 0.0 tide levels) than the other study sites, and could be exposed to air and visitor distur- bance more so than the other two channels. The third transect (“South Moss Beach’’) was located in a surge channel off south Moss Beach at the 0.0 to —1.0 foot tide level in surf grass (Phyllospadix sp.) flats. This channel was narrow and consisted mainly of a 42 m long crevice, as deep as 40 cm, that ran nearly the length of the transect. Each channel was separated from neighboring channels by at least 300 m of rocky reef. For purposes of this study, transect lines were located in areas known to be inhabited by rock crabs that were accessible to observers. Each transect line was measured from meter OO (closest to the beach) and extended seaward and lower into the intertidal zone to meter 50. Rock crabs were located within each transect using a line intercept method with the x-axis being the transect line itself and the y-axis a line drawn perpendicular to the transect line and out to the crab’s location. Crabs were captured, tagged, and released in the exact location and position (on the surface, in a crack, buried, etc.) where they were discovered. Searches for rock crabs were conducted at least once per month when possible and observations were made when tides were generally lower than 0.0 feet (mean lower low water level). Particular attention was paid to habitats in which crabs were found previously, including cracks and sandy areas beneath large rocks, which were lifted during searches (Breen and Wicksten 1988). Crabs were tagged with Floy tag #FD 67, 62 mm (2.5 inches) long, monofilament with a #20 bright orange tube bearing the legend San Mateo Co. Parks 000, and numbered sequen- tially. Tags were inserted into the right epimeral suture line above the second and third ambulatory legs with a Floy Mark II tagging gun, using a Mark II “‘Swif- tacher’’ 1.85 mm tagging needle. Only crabs over 70 mm wide were tagged. Newly- molted crabs were not tagged because they proved to be too fragile—appendages were lost and the carapace was damaged when one attempted to insert the tagging needle. During the study, the following data were collected for each individual: location (transect and location within the transect), tag number (if previously tagged), carapace width (measured in millimeters across the carapace between the ninth and tenth anterolateral teeth), sex, type of shelter used by the crab, female repro- ductive condition, damage to the crab, and any fouling. Results The sex ratio and numbers of crabs per carapace width interval at each channel is given in Tables 1-3. Three hundred eighty-seven rock crabs were tagged. The smallest measured 71 mm, the largest was 133 mm. The sex ratio of the crabs was highly skewed toward females, particularly in spring and summer. However, ovigerous females were rarely found at any time: only eight were tagged; another six (not tagged) were observed on 16 February 1989. Almost all of the crabs (97%) were found under rocks or in deep crevices. There was no sign of a shift in habitat preference in recaptured crabs—those originally found under a rock almost always were recaptured under a rock; those in a crevice usually were relocated in a crevice. Six crabs were found hidden under sea grasses, 13 MOVEMENT AND HABITAT SELECTION IN ROCK CRABS ‘g0edevieo dy) JO Wed jsapIM oY} SSOIOe SIOJIUIT|[[IW UI PoInsvsU 9ZIS Jod s[eNpPIAIpUI Jo siaquInuU oie asuURI ozIS Jod sIsqUINNY “"YUOW Yove posse sqeio [[e Sapnyout xasg 6 IZ 6 ce LI € 19 60 sTe10 | = an an €— = = ae ES Areniga-{ = I € G = = € € 686] Arenues I _ — € — _ G (6 Jaquiss9q Jans y3ty — _ = _ =— _ — — IOQquiIsAON =e a € € a = 14 (4 1940190 I — € _ — — € I Iaquis1dag POSIA 1ON — _ — = _— _ _ — isn3ny = = =. = (4 = G = Ajne I ¢ I 6 G =a el ¢ aune I = = Z = = I G KRW I v I I = = ¢ (4 Judy I I C I I fa v c yore (4 v (4 c = = v 9 Areniqo{ = Z ¢ v L = Il I 8861 Arenues a = = v 174 if C L Jaq ua99q I oa I I I (4 € € L861 JIQUIZAON S]USUIUWIO") J931e] 61 I-O1T 601-001 66-06 68-08 wu 6/-0L d W yoy pur 071 a5 ‘QAIOSOY OULIVJ, P[es93zZILJ ‘UOOSeT AYOOY 1 SNUDUUAIUD ABIUDD JO YIPIM DdedeIvD puke X9g "] ZIGQUL SOUTHERN CALIFORNIA ACADEMY OF SCIENCES 14 Jans y3styH POvSIA 10N punoj sqeio ON POUSIA 10N SJUSUTUIO?) s[e10 | Arenigo-J 6861 Arenues Jaqui909q _ JaQUIdAON — 13q010O — Joquia}dag — isn3ny (e Ayne I oun — ARI = judy ¢ yoleyy (6 Aleniqo € S86] Arenues i Jaquia09q _ L861 JOQUIDSAON JOdIE] 61I-Oll 601-001 66-06 68-08 wur 6/—-OL 4d W yquo| pue Ocl a) N loc} —_— Oo \O — LY ay lk ars ole N | otraan atAN Naan | | oa Maa) | EN oy Sea a ST eu a X9S ‘QAIOSIY VULILPY P[esodzZILJ ‘s1eY sseid Jans puev [auURYD 1e SNUDUUAJUD 4JIUDD JO YAPIM DdedeIVD PUR XB9g “7 BIQUL MOVEMENT AND HABITAT SELECTION IN ROCK CRABS 15 Table 3. Sex and carapace width of Cancer antennarius at South Moss Beach, Fitzgerald Marine Reserve. REx 70-79 120 and Month M F mm 80-89 90-99 100-109 110-119 larger November 1987 _ — — — — — — — December 6 1 — 2 3 1 — 1 January 1988 8 6 — 1 5 3 ) 3 February D} 6 — — — 4 3 1 March 7 17 _ — 4 7 10 3 April 3 6 _ _ 2 3 2, 2 May 2 12 — — 2 5 4 3 June 8 16 _ — 2 10 10 2 July 8 14 — — l 12 7 2 August — 3 — — — 1 1 1 September 1 10 — _ 1 7 2 1 October 2 16 — — _ 9 7 yp} November 1 9 — — 2; 4 3 1 December 6 18 — — 5 7 10 2 January 1989 3 4 — — 2 1 4 — February Bee Si Lane at oe = ite 1 ia Totals 57 143 0 3 29 78 66 24 three were buried in sand or gravel, and two were ranging freely in the open in tide pools. Eighty-two crabs (21%) were missing or regenerating appendages: 25 were miss- ing one chela, three were missing both chelae, 22 were missing one or more walking legs, six were missing a chela as well as one or more legs, and the remainder were missing parts of appendages or their injuries were not specified. Six had holes or cracks in the carapace. Nineteen were encrusted with coralline algae, five had barnacles attached to the carapace. The injured and encrusted crabs were repre- sented proportionally to their size frequency in the population—there was no indication of increased injury or fouling with larger crab size. Only one tagged crab (#18) showed evidence of healing from a previous injury in which the carapace was cracked. None of the tagged crabs had molted when recovered. Seventy C. antennarius (18%) were sighted alive again after tagging (Table 4). Of these, all but nine were rediscovered within five weeks after their initial tagging. Six were found within six months after tagging, two after six months, and one after nine months. One crab was sighted after an absence of two months, then found again 13 days later. All but one of the crabs absent for more than five weeks were resighted in the same transect in which it originally was tagged. Seven crabs were resighted more than once (Table 4). All of these crabs were resighted in the same transect in which they were originally tagged. Movement of the crabs within a channel was frequent. Movements of tagged crabs from their original location were approximately equal landward (35 recap- tures) versus seaward (36 recaptures), with 11 recaptures in approximately the same place. The maximum net distance moved per day per crab was 16.4 m, the minimum was none. Of those crabs that were recaptured within one month of liberty, the average distance travelled per day was approximately one meter. The 16 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES crabs captured more than once moved both landward and seaward. There was no indication of any seasonal trend in direction of movement. Twelve crabs were found dead. Seven of these crabs died within one month of tagging. One was soft-shelled when tagged, and may have been injured. Three dead crabs were found after three, five, nine, and 11 months, respectively, but crab #7 was found dead over 700 days after it was tagged. All of the dead crabs, and three tags that came loose from tagged crabs, were found only a short distance from the study areas, usually on the narrow beach near the cliffs above the tide pools. Although intertidal areas of the Reserve are heavily visited by classes, guided tours, and the general public throughout the year, no tags or tagged crabs were found or reported elsewhere in the Refuge during the period of study. Discussion As in our previous study, we found no evidence of long-term defence of a fixed territory in rock crabs. Carroll (1982), in a study of subtidal rock crabs in Diablo Canyon, reported that rock crabs could travel distances of up to 7 kilometers. Because of high surf, we were unable to monitor movements of crabs into subtidal regions. Crabs in our study areas moved up to 35.7 m within or between transects. Those that were recaptured seemed to stay in a channel in a small area (perhaps as small as 500 m7?) for as much as a month, and then leave permanently. Of the 317 crabs that were not observed again after tagging, some undoubtedly died and others lost their tags. Carroll (1982) estimated tag loss at 14% in his study at Diablo Canyon. The crabs that were not recaptured at the Refuge probably moved to subtidal areas or traversed the subtidal regions in moving to other areas of the intertidal zone. The channels give easy access to subtidal areas nearby, where surf, a rugged rocky bottom and generally poor visibility (approximately 1 m) made it difficult to observe crabs. We have observed rock crabs running in synchrony with the surge in the channels at high tide, which suggests that move- ment takes place when the crabs are submerged. Indeed, the crabs only moved at low tide when greatly disturbed. During low tide, the crabs usually take shelter in cracks and under larger rocks in the channels. Shelter apparently is very important to rock crabs during the few unusually hot days that occur along this coast every year. We have recorded water temperatures of up to 20°C in the intertidal zone for more than an hour during ‘““minus”’ tides. MacKay (1943) reported that species of Cancer are restricted to waters with a mean annual temperature of 23.9°C or less. Rock crabs which remain in the intertidal zone, therefore, may be exposed to temperatures near the limits of their tolerance for more than an hour. On 7-9 April 1989, when the air tem- perature reached 32°C and water temperature reached over 20°, six dead rock crabs (not tagged) were found in tidepools in the mid-tide zone (2.5 to 0.0 foot tide level). Rock crabs seem to prefer the shelter of a deep crevice or a hiding place under a large rock. Having studied crabs in the channels previously, we are reasonably certain that we located all of the larger rock crabs present per study date and that an absence of a tagged crab was not due to it being overlooked by an observer. (Although rock crabs have been observed to bury themselves in the sand, the sand layer in the channels is shallow and the crevices are not so deep that crabs cannot be seen). Recapture rates per individual declined sharply with time, with only nine crabs MOVEMENT AND HABITAT SELECTION IN ROCK CRABS 17 Table 4. Recaptured crabs. Numbers and sex of crabs recaptured per month November 1987 — — September — — December 2M — October 1M 3F January 1988 7™M 2F November 1M 2F February 4M 3F December 1M 3F March 3M 3F January 1989 1M 6F April 1M 1F February 3M 5F May 2M 1F March 2M DE June 4M 6F June — 2F July 1M 2F August — 1F Crabs recaptured after 2 months or more Interval Crab number Date tagged Date recovered in days 17 12/3/87 2/1/88 60 56 1/6/88 6/14/88 159 63 1/18/88 5/17/88 119 92 2/1/88 6/15/88 134 152 3/31/88 6/1/88 62 216 6/14/88 3/21/89 280 274 8/29/88 3/5/89 188 366 1/3/89 6/20/89 198 384 2/6/89 6/20/89 134 Crabs recaptured more than once Crab number Date tagged Date recovered 130 3/9/88 3/14/88, 3/15/88 152 3/31/88 6/1/88, 6/14/88 298 10/11/88 10/27/88, 11/6/88 300 10/11/88 10/25/88, 10/27/88, 2 11/9/88, 11/10/88 340 12/7/88 12/19/88, 1/3/89, 1/19/89, 2/14/89 350 12/19/88 2/14/89, 2/21/89, 3/13/89 384 2/6/89 6/20/89, 7/4/89 (2%) recaptured after two months. Movement of new crabs into the transects is no doubt important in affecting recapture rates because nearly every new search of the transects revealed a different crab inhabiting a favored sheltering location under a rock or in acrevice. This apparent movement along with the low recapture rate prevents estimation of the local population size. Why the sex ratio was skewed is unknown. Carroll (1982) reported that males generally outnumbered females subtidally at Diablo Canyon except during fall. He speculated that warmer temperatures may stimulate female crabs to move inshore. Our finding that female crabs were more common in intertidal areas during spring and summer seems to contradict Carroll’s idea. Juvenile crabs often are found in the intertidal channels, where they constitute about half of the total number of crabs encountered (Breen and Wicksten 1988). Based on the injuries and encrustation we observed as well as the lack of evidence 18 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES of molting or regeneration, we suspect that most of the rock crabs we tagged were full adults at or near their maximum size. Garth and Abbott (1980) reported that adult males of the species grew to 118 mm in carapace width and females to 78 mm. Cancer antennarius may slow their molting rate or stop molting on reaching sexual maturity, as is reported in C. magister (Garth and Abbott 1980). Injuries and missing appendages were common in the rock crabs. Predators at the Refuge capable of injuring these large crabs include giant octopus (Octopus dofleini), larger red crabs (C. productus), cabezon (Scorpaenichthys marmoratus), and rarely sea otters (Enhydra lutris). Crabs could lose appendages during fights with conspecifics. Injuries may be caused by mechanical damage by battering by rocks during heavy surf. Visitor traffic also can cause injuries: fishermen have been seen tearing off chelipeds for food, then releasing the crabs; and careless visitors may smash them by overturning rocks. Data from this and our previous study give no indication of preferential seasonal movements in rock crabs. Most crabs were tagged in our third transect, “South Moss Beach.”’ The Channel and Surf Grass site can be covered by sand during winter, rendering it unsuitable for habitat by crabs. We have not observed more than 50 crabs in all three channels per study date, which suggests that the crabs occur in low densities and are dispersed through the habitat. At low tide, the crabs are found repeatedly in the same cracks, under large rocks or in pools. The finding of nine crabs back in the study area after an absence of two months or more as well as dead tagged crabs on the beach after up to nearly two years suggests that at least some of the crabs do not move long distances over time. Our observations suggest that the shelter offered by crevices and larger rocks during low tide is important to the crabs. Such shelter also could be critical during winter storms—intertidal animals often are crushed or cast ashore during winter, when waves of 3 m or more sweep across the tidal flats and channels. Acknowledgment We thank Beth Arndt, graduate student at San Francisco State University, for her enthusiastic assistance. Literature Cited Breen, R. T., and M. K. Wicksten. 1988. Sizes and seasonal abundance of rock crabs in intertidal channels at James V. Fitzgerald Marine Reserve, California. Bull. So. Calif. Acad. Sci., 87(2): 84-87. Carroll, J. C. 1982. Seasonal abundance, size composition, and growth of rock crab, Cancer anten- narius Stimpson, off central California. J. Crust. Biol., 2(4):549-561. Garth, J.S.,and D. P. Abbott. 1980. Brachyura: the true crabs. Pp. 594-630 in Intertidal invertebrates of California (R. H. Morris, D. P. Abbott, and E. C. Haderlie, eds.), Stanford Univ. Press, Stanford, Calif. MacKay, D. C. G. 1943. Temperature and the world distribution of crabs of the genus Cancer. Ecology, 24(1):113-115. Accepted for publication 31 October 1989. Bull. Southern California Acad. Sci. 89(1), 1990, pp. 19-25 © Southern California Academy of Sciences, 1990 Status and Management of Shoshone Pupfish, Cyprinodon nevadensis shoshone (Cyprinodontidae), at Shoshone Spring, Inyo County, California Daniel T. Castleberry,' Jack E. Williams,* Georgina M. Sato,! Todd E. Hopkins,! Anne M. Brasher,* and Michael S. Parker? ‘Department of Wildlife and Fisheries Biology, University of California, Davis, California 95616 ?United States Fish and Wildlife Service, Department of Wildlife and Fisheries Biology, University of California, Davis, California 95616 3Department of Land, Air, and Water Resources, University of California, Davis, California 95616 Abstract. —Shoshone pupfish (Cyprinodon nevadensis shoshone Miller), previously considered extinct, were rediscovered in 1986 from the outflow of Shoshone Spring. Plans to expand use of the water supply prompted us to map Shoshone Spring and determine habitat quality and distribution and abundance of pupfish. Pupfish in Shoshone Spring are threatened by habitat alteration, including reduced instream flow and pollution, and predation by and/or competition with introduced mosquitofish (Gambusia affinis). Because the continued existence of pupfish in Shoshone Spring seemed unlikely, we removed fish to establish a protected pop- ulation to provide progeny for reintroduction. Shoshone pupfish (Cyprinodon nevadensis shoshone Miller) were common in Shoshone Spring, Inyo County, California in 1938 (Miller 1948) but were con- sidered extinct by November 1969 (Miller 1970). Fish closely resembling Sho- shone pupfish were recently collected from the outflow of Shoshone Spring (Taylor et al. 1988). Rediscovery of pupfish and plans for further development of the spring area prompted us to gather more information on the fish and its habitat, information needed to develop a management plan to protect Shoshone pupfish. Our objectives were to map Shoshone Spring, determine the quality of the pupfish habitat, and determine the distribution and abundance of pupfish there. We sur- veyed Shoshone Spring on 15-18 April 1988. Because our observations differed from those of Taylor et al. (1988), we met Frances R. Taylor at Shoshone Spring on 25-26 May 1988 to compare the present habitat with her observations in July 1986 and to collect pupfish for propagation. We attempted to collect additional pupfish on 19 November 1988. This paper describes our findings and discusses the status and future management of Shoshone pupfish. Methods Mapping We mapped Shoshone Spring (Fig. 1) using triangulation and 10 m transects, with compass readings on all distance measurements. Thick vegetation, primarily 19 20 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES SPRING 9 SURFACE WATER oH ee WATER COLLECTION BOXES ig reeees CULVERTS i UPPER 0:0 a i 90 m2-.40 >46 Middle } >40 >46 Middle ) 54 62 Middle g 40 46 Middle 3 43 48 Middle g 41 46 Lower g 51 58 only a moderate barrier to fish moving upstream. The lower section is more likely to dry than the cement ditch because it is downstream and has a sand substrate. The river’s flood plain recently encompassed the lower end of the spring channel, suggesting that river and spring flows join at times of high water, possibly allowing fish movement between river and spring. Water temperature at the spring source was 32°C and decreased downstream to 21.6° (air temperature 20.3°) on 16 April. Specific conductance ranged from 1458 to 1755 mhos-cm?, pH from 6.7 to 7.4, and total dissolved solids from 1005 to 1207 mg:1"! on 17 April. Dissolved oxygen was 6.25 ppm at 30° at 1230 h on 16 April in the cement ditch. Fish Distribution We captured 2,625 mosquitofish (Gambusia affinis), but only 7 pupfish on 16—- 17 April. Mosquitofish were the most abundant fish in Shoshone Spring and have been abundant there as early as 1966 (Miller 1967; Selby 1977). In 1986, Taylor et al. (1988) found mosquitofish to be very abundant, but pupfish were also common (Frances R. Taylor, personal communication). Mosquitofish were much more abundant than pupfish in all areas in which we captured pupfish (Fig. 1). Although Miller (1948) collected pupfish in the upper section in 1938, we did not capture either species in this area, nor did Taylor et al. (1988) in 1986. On 26 May, we captured 6 male and 3 female large adult pupfish and many more mosquitofish in the cement ditch. Six pupfish were captured before 0930 and 3 more just before 1730, but none were captured mid-day despite a com- parable effort. On 19 November, we captured one large female pupfish from the lower section along with numerous mosquitofish and observed 359 dead mosquitofish and one dead pupfish (male, 52 mm TL) in the cement ditch. The ditch water had a chlorine-like odor, suggesting that cleaning of the upstream pool might have been a causal factor. We were subsequently informed that the pool had been drained on 17 November and the sides sprayed with Purex® bleach to remove algae (Susan Sorrells, personal communication). The chemical was washed into the cement ditch and likely caused the mortality. An approximately equal number of live mosquitofish were observed in the ditch on 19 November, indicating that the kill was incomplete or that fish reinvaded the ditch from downstream sections that did not suffer mortalities. SHOSHONE PUPFISH 23 Although recent surveys of Shoshone Spring found a wide size range of pupfish and therefore, presumably, ages (Frances R. Taylor, personal communication, Jack E. Williams, personal observation), we found only large adults (Table 1). A decline in pupfish abundance and a shift from a mixed size (age) structure to one of few large (older) fish suggests that we found only remnants of the population observed by Taylor et al. (1988) in 1986. Minckley (1969) observed a population of Gila topminnows (Poeciliopsis oc- cidentalis) as it was reduced from a large population with a mixed size structure to a population of a few old females by interactions with mosquitofish. A similar interaction between pupfish and mosquitofish in Shoshone Spring could explain reductions in pupfish numbers. Schoenherr (1981) presented evidence that mos- quitofish eliminate topminnows by predation on fry and by reducing survivorship of adult females and numerous authors have suggested mosquitofish decimate pupfish populations (Deacon and Minckley 1974; Evermann and Clark 1931; Fisk 1972; Selby 1977; Soltz and Naiman 1978). Habitat Assessment and Improvement The present quality of pupfish habitat within Shoshone Spring system is low, and permanence of that which remains is questionable. The upper section relies on overflow or leakage from spring boxes for water, making this section unsuitable as a refuge. Absence of fish in this area attests to its poor quality. For the upper section to be used as a refuge, water would have to be supplied directly from the spring boxes to ensure permanent flow. Re-establishment of a spring pool (as in Miller 1948) may help ensure future suitability of the habitat as a refuge. The middle and lower sections suffer from impermanence, especially in the overflow area, risk of chlorine pollution, and mosquitofish presence. Only the ditch holds promise as a refuge for pupfish but this area must be protected from chemical pollutants, trash, overgrowth, mosquitofish, and water diversion. Attempts to improve: pupfish habitat at Shoshone Spring should consider early accounts and attempt to return it to its original condition. A related species, the Devils Hole pupfish (C. diabolis), attained larger size and changed morphology when held for several generations in an artificial refuge (Williams 1977). Because habitats in which species evolve act to mold and maintain unique features of species (Pister 1981), it is important to return Shoshone Spring to its original condition to maintain Shoshone pupfish. Early accounts suggest water now diverted for local use once flowed from Sho- shone Spring, creating extensive fish habitat (Miller 1948; Wales 1930). Miller (1948) visited Shoshone Spring in 1937 and described two pools in the upper section and a swiftly flowing channel extending to below Old State Highway where flow slowed to form a 0.9 to 1.8 m wide, <60 cm deep creek 1.2 km long. Using Miller’s (1948) data on length and width of pupfish habitat at Shoshone Spring, we estimate 1100 to 2200 m2? of habitat in 1937. Summing areas inhabited by pupfish in our study, we estimate 740 m? of habitat on 17 April 1988. Comparing these figures, we calculate a 33 to 66% reduction in pupfish habitat at Shoshone Spring. Furthermore, this estimate only considers habitat area and not volume or flow. Because water depths were shallow over most of the area we measured and our maximum depth (<30 cm) was half of that reported by Miller (1948), it is likely that reduction in habitat volume has been much greater than the reduction 24 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES in habitat area. Selby (1977) and Taylor et al. (1988) also described greater water surface area and flow rates than we observed. Any plan to improve Shoshone Spring should include increasing available pupfish habitat, but will need to balance pupfish protection and local water use. Early accounts also described the pupfish habitat as being bordered by cattails and mesquite (Miller 1948; Wales 1930). Tamarisk is now the dominant riparian vegetation shading large portions of the spring channel. Tamarisk may alter water and nutrient balance in the spring channel. Plans to improve Shoshone Spring should consider removing tamarisk. Mosquitofish were introduced to Shoshone Spring sometime after 1938 (Miller 1948) and before 1967 (Miller 1967). Selby (1977) argued for mosquitofish erad- ication to improve Shoshone Spring’s potential as pupfish habitat. On both of our visits, we removed all of the mosquitofish we captured. Before a secure pupfish population can be reestablished in Shoshone Spring, mosquitofish must be elim- inated. Because of the low number of pupfish in the system and the tenuous nature of all habitats, we decided to remove as many pupfish as possible to establish a captive breeding population for potential reintroduction to the spring. On 26 May, we removed six male and three female pupfish from the cement ditch and on 19 November, we removed one additional female from the lower section. These fish are now being held at the University of California, Davis. In addition to propa- gating pupfish, action must be taken to restore pupfish habitat before reintroducing them. Fish Origin Taylor et al. (1988) presented three hypotheses which might explain “‘reap- pearance” of pupfish in Shoshone Spring: invasion, introduction, or non-detection (fish were there, but at very low abundance, and escaped detection). They argued that a closer resemblance of rediscovered fish to Shoshone pupfish than to Amar- gosa pupfish (C. n. amargosae, the nearest related species) lends support only to the non-detection hypothesis. Several factors have led us to question the non-detection hypothesis, and to suggest that the invasion and introduction hypotheses are still viable alternatives. First, Amargosa River and Shoshone Spring flows join at times of high water. Second, pupfish in the spring system would have been missed during several surveys (Miller 1967; Selby 1977). Even though pupfish numbers were extremely low during our visit, we were able to document their presence. Third, fish collected by Taylor et al. (1988) did not match Shoshone pupfish exactly and they suggest that differences resulted from a genetic bottleneck. Differences could also be due to Shoshone pupfish changing morphology while they inhabited the river prior to re-invasion (possibly due to the physical environment or interbreeding with Amargosa pupfish), or Amargosa pupfish coming to resemble Shoshone pupfish while isolated in Shoshone Spring. While the involvement of Amargosa pupfish in the reappearance of Shoshone pupfish seems unlikely, such an occurrence would have important implications for pupfish management and evolutionary and con- servation biology. More research is needed to determine the status of pupfish in this area of the Amargosa River drainage. This information will be necessary for proper management of these fish and their threatened habitats. SHOSHONE PUPFISH 25 Acknowledgments Susan Sorrells of Shoshone Development, Inc. kindly provided background information, housing, and permission to conduct our surveys. Betsy C. Bolster and Mignon P. Shumway of the California Department of Fish and Game, Eric Wikramanayake of the University of California at Davis, and Todd N. Persons of Oregon State University assisted in field collections. Frances R. Taylor provided a first hand account of habitat conditions that prevailed during her 1986 survey (Taylor et al. 1988). Drs. Joseph J. Cech, Jr., Peter B. Moyle and Allen W. Knight of the University of California, Davis loaned equipment. Literature Cited Deacon, J. E., and W. L. Minckley. 1974. Desert fishes. Pp. 385-488 in Desert biology, volume II. (G. W. Brown, Jr., ed.), Academic Press, New York. Evermann, B. W., and H. W. Clark. 1931. A distributional list of the species of freshwater fishes known to occur in California. California Department of Fish and Game, Fish Bulletin, 35:1-67. Fisk, L.O. 1972. Status of certain depleted inland fishes. California Department of Fish and Game Inland Fisheries Administration Report, 72-1:1-18. Miller, R. R. 1948. The cyprinodont fishes of the Death Valley system of eastern California and southeastern Nevada. Misc. Publ. Mus. Zool., Univ. Mich. No. 68. 1967. Status of populations of native fishes of the Death Valley system in California and Nevada Completion report of resource studies problems. U.S. National Park Service, 20 pp. —. 1970. Survival of fish populations. Pp. 3-5 in The rare and endangered fishes of the Death Valley system—a summary of the Proceedings of a Symposium Relating to Their Protection and Preservation. (E. P. Pister, ed.), California Department of Fish and Game. Pister, E. P. 1981. The conservation of desert fishes. Pp. 411-445 in Fishes in North American deserts. (R. J. Naiman and D. L. Soltz, eds.), John Wiley & Sons, New York. Selby, D. A. 1977. Report on the aquatic systems of the Tecopa-Shoshone area of the Death Valley system: fish, invertebrates, and habitat status. California Department of Fish and Game, 93 pp. Schoenherr, A. A. 1981. The role of competition in the replacement of native fishes by introduced species. Pp. 173-203 in Fishes in North American deserts. (R. J. Naiman and D. L. Soltz, eds.), John Wiley & Sons, New York. Soltz, D. L., and R. J. Naiman. 1978. The natural history of native fishes in the Death Valley system. Nat. Hist. Mus. L.A. Co., Sci. Ser., 30:1-76. Taylor, F. R., R. R. Miller, J. W. Pedretti, and J. E. Deacon. 1988. Rediscovery of the Shoshone Pupfish, Cyprinodon nevadensis shoshone (Cyprinodontidae), at Shoshone Springs, Inyo County, California. Bull. Southern California Acad. Sci., 87(2):67—73. Wales, J. H. 1930. Biometrical studies of some races of Cyprinodont fishes, from the Death Valley Region, with description of Cyprinodon diabolis, n.sp. Copeia, 1930(3):61-70. Williams, J. E. 1977. Observations on the status of the Devils Hole pupfish in the Hoover Dam Refugium. U.S. Bureau of Reclamation Report No. REC-ERC-77-11. Accepted for publication 25 April 1989. Bull. Southern California Acad. Sci. 89(1), 1990, pp. 26-38 © Southern California Academy of Sciences, 1990 Comparative Photosynthesis, Water Relations, and Nutrient Status of Burned, Unburned, and Clipped Rhus laurina after Chaparral Wildfire R. J. Stoddard! and Stephen D. Davis? ' Published posthumously. Mr. Roy Stoddard was lost at sea January 26, 1989 ?Natural Science Division, Pepperdine University, Malibu, California 90265 Abstract.— We compared photosynthesis, water relations, and leaf nitrogen con- tents among burned, clipped, and mature shrubs of Rhus Jaurina after a wildfire in the Santa Monica Mountains of southern California. Within the first year after fire, photosynthesis, stomatal conductance, and nitrogen contents for individual leaves were elevated for burned and clipped plants as compared to mature shrubs. Except for foliar nitrogen contents, these differences disappeared within 14 months after fire. Within 17 months after fire, resprouts of burned and clipped shrubs had a total leaf area and total leaf nitrogen content about twice that of mature plants. These results indicate that during the first year after fire, enhanced pho- tosynthetic performance of individual leaves contributes to the rapid recovery of shoot tissue—in succeeding years, enhanced total leaf area and total canopy pho- tosynthesis continue the recovery process. The chaparral vegetation of California is primarily comprised of evergreen, sclerophyllous shrubs that are resilient to periodic disturbance by wildfire (Hanes 1971; Keeley 1986). One of the most common and successful modes of recovery after wildfire is by vegetative sprouting from a root crown (James 1984; DeSouza et al. 1986). Wells (1969) pointed out some time ago that all 25 genera of chaparral shrubs in California have a crown-sprouting trait whereas only 2 genera contain species that are non-sprouters. It appears that crown-sprouting is important for the post-fire recovery of chaparral vegetation because seeds of some species are killed by fire (obligate resprouters, Keeley 1986) and post-fire seedlings generally suffer high mortality due to competition with annual herbs and grasses (Schultz et al. 1955), herbivory (Mills 1983), and water stress during the first summer drought after fire (Kummerow et al. 1985; Frazer and Davis 1988; Thomas and Davis 1989). Available data indicate that vegetative sprouting after fire provides a number of competitive advantages over seedling recruitment for chaparral shrubs: 1) prefire position is maintained, 2) shoot elongation is rapid and is initiated soon after fire, 3) reproductive maturity is quickly reached, and 4) competition for light, moisture, and nutrients is enhanced (Keeley and Zedler 1978). Obvious disadvantages of vegetative sprouting are the lack of genetic recombination with each post-fire generation and the inability to invade new microsites (Wells 1969). The mechanism for the rapid recovery of chaparral resprouts after fire is not clearly understood. Indirect evidence indicates that carbohydrates and inorganic nutrient reserves in the root and root crown are mobilized soon after fire, releasing 26 RHUS LAURINA AFTER CHAPARRAL WILDFIRE 27 bud dormancy in the root crown, and initiating the rapid regeneration of new stems and leaves (Adams and Radosevich 1978; Rundel 1981). It is probable that carbohydrate reserves in the root crown also maintain the respiratory needs and thus activity of an extensive, below ground root system (Parsons et al. 1981; DeSouza et al. 1986). The survival of a large water uptake system (root) with little surface area for water loss (leaves) suggest a luxurious supply of moisture to shoot tissue during the first growing season after fire. Thus water status and turgor potentials remain favorable for continued shoot elongation of resprouts even during dry summer months (DeSouza et al. 1986; Saruwatari and Davis 1989). In addition to improving the water status of resprout tissue, retention of a large active root system after shoot removal may also facilitate the rapid uptake of inorganic nutrients from post-fire soils (Rundel and Parsons 1980). Elevated water and nutrient status probably contribute to the high stomatal conductance and photosynthetic rates observed for resprouts during the first growing season after fire (Radosevich and Conard 1980; Oechel and Hastings 1983; DeSouza et al. 1986; Hart and Radosevich 1987; Hastings et al. 1989). Here we examine the resprouting process of a common member of coastal chaparral of southern California: Rhus laurina Nutt. (laurel sumac). Our objectives were to compare the water status, leaf nitrogen content, and photosynthetic per- formance of unburned shrubs to resprouts of burned and clipped individuals. We predicted that relative to unburned shrubs, 1) resprouts of burned and clipped shrubs would have higher water status and leaf nitrogen contents, 2) resprouts of burned and clipped shrubs would initially have enhanced photosynthetic rates, and 3) eventually differences between treatments would disappear as total leaf area returned to pretreatment values. Furthermore, we reasoned that clipped shrubs would have lower leaf nitrogen contents and photosynthetic rates than burned shrubs because the soil beneath clipped shrubs would not receive nutrient- rich ash deposited by the fire. Study Site Our study site is located 1 km east of the Malibu campus of Pepperdine Uni- versity (34°02’30’N, 113°41'44”W), on a SW facing slope (mean incline of 10°) of the Santa Monica Mountains, at an elevation of 150 m. The prefire stand consisted of mixed chaparral shrubs dominated by Ceanothus megacarpus Nutt., and Rhus laurina Nutt. (Frazer and Davis 1988). Nomenclature follows Munz (1974). The study site had not burned since September 1970 (Los Angeles County Fire Department). Our study site was burned in a 0.6 ha wildfire on 21 April 1984. During the fire, fire fighters hand-cleared a 5 m wide fire-break around the perimeter of the burn site. As a result, burned shrubs were surrounded by a 5 m wide strip of clipped shrubs and outside this strip was an extensive stand of unburned plants. This facilitated a comparison of three treatments— burned, clipped, and unburned shrubs. We were careful to select clipped and unburned shrubs that were uphill of the burned treatment. Therefore, it was unlikely that nutrients leached from burned soils during fall and winter rains were received by clipped and unburned individuals. We chose R. /aurina as our experimental subject because previous data indicated that this species had a prominent root crown, deep roots, and virtually 100% 28 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES resprouting success after wildfire (DeSouza et al. 1986; Frazer and Davis 1988; Thomas and Davis 1989). On 14 October 1985, a second wildfire burned a large area surrounding our study site. Once the fire reached our previously established fire-break, it depleted its fuel and extinguished itself. However, the clipped shrubs in the fire-break were heat damaged and measurements on these plants were discontinued. A number of mature individuals were undamaged by the second fire, permitting us to con- tinue our original comparison between burned and unburned treatments. Methods Soil Water Potential and Soil Temperature An electric drill and masonry bit were used to drill one hole beneath the un- burned shrubs, one beneath post-fire resprouting shrubs, and one in an open area of the burn site, devoid of resprouts. We did not drill a hole beneath clipped shrubs. Each hole was 25 mm in diameter and 2 m deep. Soil psychrometers (model PCT-55-30, Wescor Inc., Logan, Utah) were calibrated at 4 points using standard NaCl solutions. We installed 8 psychrometers in each hole at 0.25 m intervals in depth. Holes were back filled with original soil. A dew point micro- voltmeter (model HR-33T, Wescor Inc.) was used to measure soil temperatures and soil water potentials, with these psychrometers, once every two weeks between May 1985 and January 1986, following the precautions and procedures given by Weibe et al. (1977) and Weibe and Brown (1979). We measured soil temperature and water potential at dawn because we wanted to standardize the time of mea- surement and because we found thermal gradients, especially near the soil surface, to be minimal at this time of day. Soil water potential values were not accepted if zero-offset readings exceeded 3.0 wV. Predawn Water Potentials We measured leaf water potentials (Scholander et al. 1965) every two to three weeks between May 1985 and January 1986. Readings were taken on 2 leaves from each of 3 plants in each treatment. To prevent phloem exudate from inter- fering with the measurement of true xylem water potentials, phloem was removed from petioles, with electrical wire strippers, just prior to the insertion of each leaf in the pressure chamber. Periodic measurements of predawn water potentials were also taken on C. megacarpus in the mature, unburned stand to aid our assessment of the relationship between plant water status and soil water potential. Thomas and Davis (1989) have found that maximum rooting depth of C. megacarpus does not exceed 2 m whereas roots of R. /aurina extend much deeper than 5 m. We reasoned that a comparison of predawn water potential between C. megacarpus and R. /aurina growing together would indicate the soil moisture environment of shallow roots, versus deep roots in our system. Furthermore, the theory of hy- draulic lift (Richards and Caldwell 1987) suggests that deep rooted shrubs should loose moisture to shallow, dry regions of the soil overnight. If this was the case in Our system, we predicted that the soil moisture profile beneath unburned R. /aurina in the presence of C. megacarpus would be much different than beneath R. laurina resprouts devoid of C. megacarpus (C. megacarpus is a non-sprouter RHUS LAURINA AFTER CHAPARRAL WILDFIRE 29 after fire and thus vegetative sprouts of this species were absent in the burned and clipped treatments). Pressure- Volume Curves In order to compare the tissue water relations of the burned, clipped, and unburned shrubs, we used a modified pressure volume technique that has been fully described elsewhere (Davis and Mooney 1986a; DeSouza et al. 1986). In June of 1985, one branch from each of four burned, four clipped, and four un- burned plants was cut under water, covered with a plastic bag, and allowed to rehydrate overnight in complete darkness. The next morning, one fully expanded leaf was removed from each branch and used to determine the osmotic potential at saturation (W,,.1), OSmotic potential at the turgor loss point (WV.«,)), relative water content where turgor is lost (RWC,,), bulk modulus of elasticity (€), bound water of the bulk tissue (B), and the saturation weight/dry weight ratio (SW/DW). Diurnal Leaf Conductance and Photosynthesis Diurnal photosynthesis and leaf conductance to water vapor diffusion were measured using a portable photosynthesis system (model LI-6000, Li-Cor Inc., Lincoln, NE). Measurements were taken on 3 fully illuminated and enlarged leaves of each plant for 3 plants from each treatment. In July 1984, initial readings were taken on burned and unburned shrubs only. The following season, 1985, mea- surements were made on all three treatments, burned, clipped, and unburned, once each month, from May to August 1985. Nitrogen Content of Leaf and Stem Tissue After each diurnal measurement of photosynthesis, experimental leaves were harvested and brought back to the laboratory for nitrogen determinations (N = 9 for each treatment). The area of each leaf was calculated using a digitizer (Hipad, Houston Instrument, Austin, Texas). Leaves were then oven dried at 80°C for at least 48 hours, weighed to the nearest 0.1 mg with an analytical balance, and used to measure nitrogen content (% dry weight) by the micro-Kjeldahl digestion and titration method (Nutritional Analysis Lab., Range Science Dept., Colorado State Univ., Fort Collins, Colorado). Leaf specific weight and total leaf nitrogen per area of the leaf were calculated. Stem tissue was also dried, weighed, and subjected to nitrogen analysis in September 1985. Total Shoot Biomass and Leaf Area On 28 September 1985, we estimated the average leaf area and shoot biomass of unburned, clipped, and burned shrubs by the following method. First, we randomly selected 3 individuals from each treatment and counted the number of main branches per plant. Second, we randomly selected three main branches from each shrub and calculated the total leaf area per branch by taking the product of length and width of each leaf and multiplying by a constant (0.761) derived from a regression of leaf area versus leaf dimension (7? = 0.97, N = 39). Finally, stem and leaf tissue from each branch were separated, oven dried at 80°C for at least 48 hours, and weighed to the nearest | mg. These mean values of leaf area and 30 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES 23 August 1985 Bare Ground Resprout Stand Mature Stand 0.0 273C 26.4C A B 23.5C c -0.5 _—~ Ex <= td jo AES ® Q -2.0 24.6C 235C 20.7 C -2.5 -7 6 5 4 3 2 1F 0 7 6 5 -4 3 2 1 0 i 6 5 4 3 2 1 te) Soil Water Potential (MPa) Fig. 1. A—C. Soil water potentials and corresponding temperatures at 0.1 m and 2.0 m depths for (A) bare ground, (B) resprout, and (C) mature sites on 23 August 1985. dry weights per branch were then multiplied times the average number of branches per plant in each treatment to calculate total shoot biomass and leaf area. Statistical Analysis Mean values of predawn water potential, nitrogen content, tissue water param- eters, and shoot biomass were compared by either a Student’s f-test, or a one way ANOVA depending on the number of groups involved. Mean values of diurnal photosynthesis, leaf conductance, and leaf water potentials were compared by two way ANOVA followed by a Scheffe’s multiple range test. All means were compared at the 0.05 level of significance (Sokal and Rohlf 1981). Results Soil Water Potential and Soil Temperature Soil water potentials continually decreased at the bare ground, resprout, and mature sites as the summer drought progressed (data not shown). In August 1985, the bare ground site, presumably devoid of active root systems, had an almost linear decline in water potential with depth whereas the other two sites varied in their relation between water potential and depth (Fig. 1). These patterns were persistent throughout the summer drought period (data not shown). During the summer, the difference in soil temperature between a depth of 0.25 m and 2.0 m was about 3°C at the bare ground, resprout, and mature sites. At the peak of the drought, in August 1985, soil temperatures at a depth of 0.25 m were higher at the bare ground and resprout sites than at the mature stand, probably because of shading provided by the foliage of mature shrubs (Fig. 1). The lowest temperature measured (20.7°C) was coincident with the highest soil water potential (—0.6 MPa), at a depth of 2.0 m in the mature stand. RHUS LAURINA AFTER CHAPARRAL WILDFIRE 31 Leaf Water Potential (MPa) Month of Year (1985) Fig. 2. Seasonal change in predawn water potentials from May to December 1985 for mature Ceanothus megacarpus (O), and three treatments of Rhus /aurina— mature (LD), burned (A), and clipped (@). Predawn Water Potentials There was a gradual decrease in predawn water potentials for burned, clipped, and unburned shrubs of R. /aurina during the summer drought of 1985 (Fig. 2). Water potentials were similar between treatments and never reached values lower than —2 MPa. In contrast, mature shrubs of Ceanothus megacarpus came under severe water stress during summer months and reached predawn water potentials of —7 MPa by September 1985. Pressure-Volume Curves Tissue water relations between burned, clipped, and unburned shrubs of R. laurina were similar in June 1985 (Table 1). The only significant difference among treatments was that unburned shrubs had more rigid tissues than clipped shrubs (lower bulk modulus of elasticity). The osmotic potentials where bulk leaf tissues lost turgor varied between — 2.2 and —2.4 MPa, values lower than predawn water potentials (Fig. 2) and minimum diurnal water potentials (Fig. 3C, F, I). Diurnal Leaf Conductance and Photosynthesis Photosynthetic rates measured 3 months after the fire of April 1984 were sig- nificantly higher at 3 points of the diurnal for the burned plants when compared to the unburned controls (Fig. 3A). Similarly, the burned treatment showed ele- vated conductance rates and water potential readings throughout the day in com- 32 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES Table 1. Mean values of osmotic potential at saturation (W,...)), Osmotic potential at turgor loss point (V.4,)), bulk modulus of elasticity (€), bound water (B), relative water content at the turgor loss point (RWC,,), and saturation weight/dry weight ratio (SW/DW) for leaves of burned, clipped, and mature Rhus /aurina shrubs in June 1985. Mean values were compared by one way ANOVA followed by a Scheffe’s multiple range test. Burned Clipped Mature Wisat) (MPa) —1.6 ile —1.8 (0.06) (0.08) (0.09) Wtip) (MPa) wD) =e —2.4 (0.02) (0.09) (0.08) e (MPa) 9.2 12.3 6.8° (2.69) (1.73) (0.54) B (%) 36.1 41.7 35.9 (2.1) (3.6) (7.4) RWC,,, (%) 84.3 86.9 83.4 (1.5) (0.6) (0.9) SW/DW 2.8 27 2.6 (0.03) (0.15) (0.04) ' Values in parentheses represent | S.E., N = 4. ? Letters in superscript represent significant differences at the 0.05 level from; b = burned, c = clipped, and m = mature plants. 20 July 1984 14 May 1985 29 June 1985 Bh ; Ge iy, eS soa Photosynthesis (umo] mv 2s~!) Conductance (mmo) m-2s~!) Leaf Water Potential (MPa) 400 900 1400 1900 400 900 1400 1900 400 900 1400 1900 Time of Day (PST) Fig. 3. Diurnal patterns of leaf photosynthesis (A, D, G), leaf conductance to water vapor diffusion (B, E, H), and leaf water potentials (C, F, 1) for Rhus laurina following the wildfire of 21 April 1984. Treatments include mature (@), burned (A), and clipped (@) individuals. Superscript letters indicate significant difference (P < 0.05) at that point from the mature shrubs where b = burned treatment and c = clipped treatment. RHUS LAURINA AFTER CHAPARRAL WILDFIRE 33 Table 2. Comparison of leaf nitrogen contents for burned, clipped, and mature shrubs expressed as a percentage (grams nitrogen/grams dry weight of leaf tissue) and as mass per unit area (grams nitrogen/area of leaf tissue). Mean values were compared either by Students t-test or one way ANOVA followed by a Scheffe’s multiple range test depending on whether two or three treatments were involved. % Leaf nitrogen Area leaf nitrogen (g/g) (g/m?) Date Burned Clipped Mature Burned Clipped Mature July 84 1.09 — 0.72° — - _ (0.01) (0.03) May 85 1.49 1.66 1.18>¢ 2.56 2.58 2.20>¢ (0.09) (0.09) (0.05) (0.02) (0.09) (0.07) June °85 1.12 1.08 0.95>¢° 2.49 2.37 Dawe (0.05) (0.03) (0.06) (0.17) (0.11) (0.12) July ’85 1.12 0.98 0.95° 3.19 2.88 2.57 (0.10) (0.06) (0.11) (0.12) (0.11) (0.24) August ’85 1.18 1.18 0.92>¢ 2.90 2.82 Deer} (0.04) (0.05) (0.03) (0.20) (0.26) (0.15) October 85 1.03 — 0.90° 2.75 — 2.01° (0.03) (0.03) (0.07) (0.10) January ’86 1.94 — 1.34> 2.84 — 2.45° (0.14) (0.16) (0.07) (0.07) July ’86 1.17 — 1.04 2.57 — 2.09 (0.06) (0.02) (0.10) (0.05) ' Values in parentheses represent | S.E., N = 9. ? Letters in superscript represent significant differences from mature shrubs: b = burned, and c = clipped, at a 0.05 confidence level. parison to the mature treatment (Fig. 3B, C). Readings were not taken on the clipped treatment at this time. Measurements taken;on the same plants in May of the next year, and on the additional clipped treatment, were similar in that both the burned and hand cleared shrubs had slightly elevated photosynthetic rates over mature shrubs (Fig. 3D). However, these differences were not large, and only the clipped treatment was significantly higher in photosynthetic rate than mature plants at one point in the day. Conductance rates were significantly greater for both burned and clipped treatments than mature plants during early morning hours (Fig. 3E). Water po- tentials of the clipped plants were significantly higher than the mature plants at two points during the day, while the burned plants were not significantly different from mature plants at any time (Fig. 3F). The physiological differences found in May were not observed in June. There were no significant differences in photosynthetic rates, conductance rates, or the water potentials at any hour of the day between any of the groups (Fig. 3G-I). Monthly diurnal measurements indicated no significant difference between groups throughout the remainder of the summer and fall (data not shown). Nitrogen Content of Leaf Tissue Percent leaf nitrogen for burned shrubs was elevated over mature plants on every month measured for two years following fire (Table 2). Leaf nitrogen ex- pressed on an area basis was also elevated over mature plants on all months except 34 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES Table 3. Biomass and nitrogen distribution between leaf and stem tissues of burned, clipped and mature Rhus laurina shrubs on 28 September 1985. Mean values were compared by one way ANOVA followed by Scheffe’s multiple range test. Biomass Nitrogen (g) (g) Burned Clipped Mature Burned Clipped Mature Leaf 881 835 467>° 10.4 9.9 4.3>¢ (266) (95) (53) (3.1) (1.1) (0.5) Stem 281 396 1596>° 1.6 1.9 6.5>¢° (985) (51) (181) (0.5) (0.3) (0.7) Total 1163 1232 2063>< 12.0 11.8 10.4 (351) (146) (234) (3.6) (1.4) (1.2) ' Values in parentheses represent 1 S.E., N = 3. ? Letters in superscript indicate significant differences from mature shrubs at a 0.05 confidence level: b = burned, and c = clipped treatments. July and August 1985 (Table 2). Clipped shrubs had a higher percentage of leaf nitrogen than mature plants on all months measured except July 1985. However, when leaf nitrogen contents of clipped shrubs were expressed on an area basis, significant differences between treatments were observed only in May 1985 (Ta- ble 2). Total Shoot Biomass, Nitrogen, and Leaf Area Total leaf areas in September 1985 were significantly greater for both the burned and clipped treatments when compared to the unburned, mature plants. The burned treatment had an area of 7.4 m? + 1.6 (SE, N = 3), the clipped treatment 6.4 m? + 1.2, and the unburned treatment 2.7 m? + 0.06. Most of the shoot biomass was in leaf tissue for both the burned and clipped treatments by September 1985 whereas mature shrubs had most of their shoot biomass in stem tissue (Table 3). Total shoot biomass was significantly lower in both resprout treatments as compared to mature shrubs, even after 17 months of postfire regrowth. Most of the total shoot nitrogen was located in the leaf tissues of resprouts, whereas most of the total shoot nitrogen was located in the stem tissue of mature plants (Table 3). Total shoot nitrogen was not significantly dif- ferent among treatments. Discussion Water Relations The water status of R. /aurina resprouts were significantly higher than for mature shrubs during the first summer drought after fire but this difference disappeared by the second summer of regrowth (Fig. 3; Table 1). We suspect that this pattern was caused by the large root system of R. /aurina initially supplying luxurious amounts of moisture to a diminutive shoot but as leaf areas returned to prefire values these differences disappeared. There were large differences in soil moisture profiles that developed among bare ground, resprout, and mature sites by the second summer drought after fire (Fig. 1). Because the soil at our study site is a relatively deep and uniform deposit of RHUS LAURINA AFTER CHAPARRAL WILDFIRE 35 sandy loam, we suspect that this pattern was caused by differences in root activity. The bare ground site represented a soil moisture profile characteristic of a region devoid of deep roots. Only sparse numbers of herbaceous grasses and annuals with some seedlings of C. megacarpus and R. laurina were present. The seedlings did not have a rooting depth greater than 50 cm by August i985 (Frazer and Davis 1988). Therefore, we assume that the decline in water potential with soil depth was primarily due to evapo-transpiration from the upper soil horizons (first 50 cm). In contrast to the bare zone, the mature site consisted of a dense stand of mature R. /aurina and C. megacarpus shrubs that had very different rooting depths-greater that 5 m for R. /aurina and less than 2 m for C. megacarpus (DeSouza et al. 1986; Thomas and Davis 1989; Davis and Mooney 1986a). Therefore, we suspect that the extremely low soil water potential in the first 1.5 m depth was due to the shallow root activity of C. megacarpus which had a predawn water potential near —7 MPa by the end of August 1985 (Fig. 2). In contrast, predawn water potentials for mature R. /aurina growing adjacent to C. megacarpus where only about — 1.5 MPa in August and corresponded to soil water potentials below 1.5 m (Fig. 2). Most interesting were the relatively high soil water potentials at all depths below 0.5 m at the resprout site. This particular site had a dense cluster of 8 to 10 resprouting shrubs of R. /aurina. We suspect that the deep roots of R. laurina were removing moisture from deep soil reserves but shallow roots were loosing some of the water to shallow soil horizons, especially overnight. This interpre- tation needs additional verification but it is consistent with the patterns reported for Artemisia tridentata (Richards and Caldwell 1987) and Prosopis tamarugo (Mooney et al. 1980) under field conditions. Diurnal Leaf Conductance and Photosynthesis It appears that within three months after fire, there is a significant enhancement in photosynthesis, conductance, and water potential for burned R. /aurina as compared to unburned shrubs (Fig. 3A—C). These results are consistent with those reported by DeSouza et al. 1986. However, unlike the results of DeSouza et al., the observed enhancement in our experimental system disappeared within 14 months after fire (Fig. 3G—I). The reason for this difference is not clear. Several factors may be involved, the most important of which is a lower availability of soil nutrients and moisture at our study site. The mean canopy height of mature shrubs at the DeSouza site was 4.1 m + 0.32 (SE, N = 10) whereas the mean canopy height of mature shrubs at our site was only 1.6 m + 0.10, suggesting very different resource availabilities for overall shoot construction. Nitrogen Content of Leaf and Stem Tissues The clipped plants at our study site were similar to burned plants, although the data are limited. At no time did we find significant differences in photosynthesis, conductance, leaf nitrogen, and water relations between burned and clipped treat- ments (Figs. 2, 3; Tables 1, 2). By September 1985, 17 months after wildfire, total leaf area, biomass, and nitrogen of shoots were almost identical between burned and clipped shrubs (Table 3). Since we found no evidence that burned shrubs had a significant nutrient en- hancement over clipped shrubs, we suspect that elevated values of leaf nitrogen were not a direct result of greater nitrogen availability and uptake from burned 36 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES soils. It is unlikely that the high foliar nitrogen observed for clipped shrubs came from the leachate of burned soils because the plants examined were uphill from the burn site. Furthermore, since the water potential between the soil surface and a depth of 1.5 m during summer months were lower than water potentials of plant tissues, it is improbable that shallow roots were actively taking up soil nitrogen from postfire char and ash deposited at the soil surface — yet leaf nitrogen remained elevated during summer months (Table 3). This implies that the elevated nitrogen in resprouts, whether burned or clipped, came from inorganic nutrients stored in the root. Although there were no differences in total shoot nitrogen between burned, clipped, and mature shrubs, there was a dramatic difference in the distribution of nitrogen between leaf and stem compartments. Most of the mature shrub nitrogen was located in stems, whereas most resprout nitrogen was in leaves (Table 3). This difference in total nitrogen was primarily due to greater biomass of stem tissue in mature shrubs. Because leaf nitrogen has been shown to be directly proportional to photosynthetic rates in chaparral species (Field and Mooney 1983; Field et al. 1983), the increased nitrogen within leaves of the resprouts may enhance carbon gain to support new leaf construction. The increase in total leaf area would then lead to an overall increase in canopy photosynthesis as compared to mature plants, resulting in higher levels of whole plant carbon gain to support rapid growth rates. In addition, resprouts would not have the respiratory expense of sustaining a large stem biomass characteristic of unburned, mature plants. This may be one of the underlying mechanisms by which resprouts rapidly return to prefire conditions. It is noteworthy that the total shoot nitrogen was the same among treatments by September 1985. This indicates that nitrogen may be limiting the construction of shoot tissues in our system. As shrubs are required to grow new and longer stems to compete for light, much of the available nitrogen becomes tied up in stem tissues and less becomes available for the construction of leaves. It may be that the nitrogen available for construction of shoots is not only limiting but fairly stable in our system throughout a fire cycle. Acknowledgments Weare grateful to Marian Moyher, Peter Weldon, and Janet Davis for assistance with field equipment, to Dr. Kenneth Perrin for administrative support, and to Dr. Gary Tallman for helpful comments on a earlier version of the manuscript. This work was supported by grants from the John Stauffer Charitable Trust and the University Research Council of Pepperdine University. A version of this paper was submitted in partial fulfillment of the requirements of the Honors Biology program at Pepperdine University, Malibu, California. Literature Cited Adams, D. R., and S. R. Radosevich. 1978. Regulation of chamise shoot growth. Amer. J. Bot., 65: 320-325. Davis, S.D. 1989. Patterns in mixed chaparral stands: differential water status and seedling survival during summer drought. Pp. 97-105 in The California Chaparral: Paradigms reexamined. S. C. Keeley (ed.), Natural History Museum of Los Angeles County, Calif. , and H. A. Mooney. 1986a. Tissue water relations of four co-occurring chaparral shrubs. Oecologia (Berlin)70:527-535. RHUS LAURINA AFTER CHAPARRAL WILDFIRE 37 , and 1986b. Water use patterns of four co-occurring chaparral shrubs. Oecologia (Berlin), 70:172-177. Desouza, J., P. A. Silka, and S. D. Davis. 1986. Comparative physiology of burned and unburned Rhus laurina after chaparral wildfire. Oecologia (Berlin), 71:63-68. Frazer, J.,and S. D. Davis. 1988. Differential survival of chaparral seedlings during the first summer drought following wildfire. Oecologia (Berlin), 72:215-221. Field, C., and H. A. Mooney. 1983. Leaf age and seasonal effects on light, water, and nitrogen use efficiency in a California shrub. Oecologia (Berlin), 56:341-347. —, J. Merino, and H. A. Mooney. 1983. Compromises between water-use efficiency and nitrogen- use efficiency in five species of California evergreens. Oecologia (Berlin), 60:384—-389. Hanes, T. L. 1971. Succession after fire in the chaparral of southern California. Ecological Mono- graphs, 41:27-52. Hart, J. H., and S. R. Radosevich. 1987. Water relations of two California chaparral shrubs. Amer. J. Bot., 74:371-384. Hastings, S. J., W. C. Oechel, and N. Sionit. 1989. Water relations and photosynthesis of chaparral resprouts and seedlings following fire and hand clearing. Pp. 107-113 in The California Chap- arral: Paradigms Reexamined. S. C. Keeley (ed.), Natural History Museum of Los Angeles County, Calif. James, S. 1984. Lignotubers and burls-their structure, function and ecological significance in med- iterranean ecosystems. Bot. Rev., 50:225—266. Keeley, J. E. 1986. Resilience of mediterranean shrub communities to fire. Pp. 95-112 in Resilience of Mediterranean Ecosystems. B. Dell (ed.), Dr. W. Junk, New York. ,and P. H. Zedler. 1978. Reproduction of chaparral shrubs after fire: a comparison of sprouting and seeding strategies. Amer. Midl. Nat., 99:142-161. Kummerow, J., B. A. Ellis, and J. N. Mills. 1985. Post-fire seedling establishment of Adenostoma fasciculatum and Ceanothus greggii in southern California chaparral. Madrono, 32:148-157. Mills, J. N. 1983. Herbivory and seedling establishment in post-fire southern California chaparral. Oecologia (Berlin), 60:267—270. Mooney, H. A., S. L. Gulmon, P. W. Rundel, and J. Ehleringer. 1980. Further observations on the water relations of Prosopis tamarugo of the Northern Atacama Desert. Oecologia (Berlin), 44: 177-180. Munz, P. A. 1974. A flora of southern California. Univ. Calif. Press, Berkeley, Calif. p. 1086. Oechel, W. C., and S. J. Hastings. 1983. The effects of fire on photosynthesis in chaparral resprouts. Pp. 274-285 in Med-type Ecosystems: The Role of Nutrients. F. J. Druger, D. T. Mitchell, J. U. M. Jarvis (eds.), Springer, New York. Parsons, D. J., P. W. Rundel, R. P. Hedlund, and G. A. Baker. 1981. Survival of severe drought by a non-sprouting chaparral shrub. Amer. J. Bot., 68:973-979. Radosevich, S. R., and S. G. Conard. 1980. Physiological control of chamise shoot growth after fire. Amer. J. Bot., 67:1442-1447. Richards, J. H., and M. M. Caldwell. 1987. Hydraulic lift: substantial nocturnal water transport between soil layers by Artemisia tridentata roots. Oecologia (Berlin), 73:486—-489. Rundel, P. W. 1981. Fire as an ecological factor. Pp.501-—538 in Plant Physiological Ecology I, Responses to the Physical Environment. O. L. Lange, P. S. Nobel, C. B. Osmond, and H. Ziegler (eds.), Springer, New York. , and D. J. Parsons. 1980. Nutrient changes in two chaparral shrubs along a fire-induced age gradient. Amer. J. Bot., 67:51-58. Saruwatari, M. W., and S. D. Davis. 1989. Tissue water relations of three chaparral shrub species after wildfire. Oecologia (Berlin). 80:303-308. Schultz, A. M., J. L. Launchbaugh, and H. H. Biswell. 1955. Relationship between grass density and brush seedling survival. Ecology, 36:226—238. Scholander, P. F., H..T. Hammel, E. D. Bradstreet, and E. A. Hemmingsen. 1965. Sap pressure in vascular plants. Science, 148:339-346. Sokal, R. R., and F. J. Rohlf. 1981. Biometry. W. H. Freeman & Co., San Francisco, p. 859. Thomas, C. M., and S. D. Davis. 1989. Recovery patterns of three chaparral shrub species after wildfire. Oecologia (Berlin). 80:309-320. Weibe, H. H., R. W. Brown, and J. Barker. 1977. Temperature gradient effects on in situ hygrometer measurements of water potential. Agron. J., 69:933-939. 38 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES , and R. W. Brown. 1979. Temperature gradient effects on in situ hygrometer measurements of soil water. Agron. J., 71:397-401. Wells, P. V. 1969. The relation between mode of reproduction and extent of speciation in woody genera of the California chaparral. Evol., 23:264-267. Accepted for publication 10 November 1989. Bull. Southern California Acad. Sci. 89(1), 1990, pp. 39-41 © Southern California Academy of Sciences, 1990 Research Notes Mass Mortality of the Reef Coral Pocillopora on the South Coast of Baja California Sur, Mexico Wilson (1988) reported a geographic range extension for the reef coral Pocil- lopora from its well-known occurrence in the Bahia Pulmo area of the southern Gulf of California to Cabo San Lucas, the cape separating the Gulf from the Pacific Ocean. His note was based on observations made in February 1988, at which time the coralla appeared to be luxuriantly healthy except for lack of zooanthellae (“bleaching”’) at the tips of many coralla (Wilson, 1988, fig. 3). Revisitation of the area in July 1989 disclosed that at least 95% of the Pocillopora spp. coralla at Punta Palmillas were dead and overgrown with encrusting organ- isms (bryozoans, worms, barnacles, several kinds of algae). Many of even the largest coralla were nearly unrecognizable. A granite outcropping on the sandy beach formerly covered by Pocillopora spp. coralla (Wilson, 1988, figs. 4, 5) was scoured to the rock surface and showed no evidence of former encrustations. Similar conditions existed at Cabo San Lucas, where an estimated 70% of the Pocillopora spp. coralla at Wilson’s 1988 locality were dead and covered by encrusting organisms (Fig. |), including barnacles up to 2 cm in diameter. At Bahia Pulmo, Pocillopora spp. coralla were estimated to be about 10% dead in 5-7 m depths of open areas, perhaps not an abnormal percentage (Hector Reyes, personal communication). However, more than 50% were dead in 3 m depth in the protected rocky cove at the south end of the bay (Fig. 2) by my estimate. Coralla of other genera (Pavona, Porites, Tubastrea) observed at these localities by me appeared to be healthy. Reasons for this mass mortality were not apparent. Although large building projects (hotels, condominiums) and dredging contributed to an increase in sus- pended sediment and other pollution in the Punta Palmillas and Cabo San Lucas areas, the lack of commercial development at Bahia Pulmo indicates another cause for the mortality. If extreme water temperature changes such as reported for the area by Klimley and Butler (1988) are the cause, as suggested by the apparent gradient of increasing mortality from deeper to shallower waters at Bahia Pulmo, then coralla of only one genus would appear to be sensitive to it. A number of corallivores are known to feed on Pocillopora. Moyer, Emerson, and Ross (1982) reported the gastropod Drupella rugosa to be selectively destroy- ing coralla of some genera, including Pocillopora, in the western Pacific. Glynn and Wellington (1983) cited the echinoid Eucidaris thouarsii as grazing in large numbers on live coralla of Pocillopora in the Galapagos Islands and also reported predation by two species of hermit crabs, four species of mollusks, two species of starfish (including the infamous Acanthaster planci), and several species of fish. Of these, I observed only the gastropod Quoyula madreporarum in moderate numbers on coralla of Pocillopora, but this species is thought to remain near its attachment scar and do little damage to the coral (Glynn and Wellington, 1983). 39 40 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES Fig. 1. Fragment from a dead, heavily encrusted corallum of Pocillopora sp. collected in July 1989 at Cabo San Lucas. x 0.6. I saw a few specimens of the corallivore pufferfish Arothron meleagris swimming near Pocillopora heads in Bahia Pulmo, but not in numbers that could account for the deaths of entire coralla, although they may be responsible for the “bleached” tips. Absence of unusual numbers of corallivores and lack of destruction of delicate calicular structures in the coralla observed by me seems to rule out corallivores as a cause of the mass mortality. Despite ready accessibility (e.g., Punta Palmillas is a 15 minute drive on paved highway from the international airport near San José del Cabo), reef corals of the area have attracted few researchers. Indeed, all aspects of reef biology and ecology in this region need to be investigated. Increasing building programs may threaten the existence of reef organisms in places. I am grateful to M. en C. Oscar Arizpe C., Departamento de Biologia Marina, Universidad Autonoma de Baja California Sur, for providing transportation and a boat at Bahia Pulmo, official permission for the examination and collection, RESEARCH NOTES 41 Fig. 2. Underwater view taken in July 1989 of mostly dead coralla of Pocillopora spp. in cove at south end of Bahia Pulmo. and selection of areas to dive there. Sr. Hector Reyes B., who is studying the reef corals at Bahia Pulmo, generously shared his observations on present and past conditions there. Several observers assisted with the underwater survey in addition to M. en C. Arizpe and Sr. Reyes: Dr. Shelton Applegate, Dr. Judith T. Smith, Mr. Jamie Smith, and Sr. Paulino Perez G. I am grateful to them all. Everyone except Sr. Perez dived at Bahia Pulmo; all but Dr. Applegate and M. en C. Arizpe dived at Punta Palmillas; Cabo San Lucas was examined by Sr. Perez, Sr. Reyes, and myself. Literature Cited Glynn, P. W., and G. M. Wellington. 1983. Corals and coral reefs of the Galapagos Islands. Univ. California Press, Berkeley, 330 pp. Klimley, A. P., and S. B. Butler. 1988. Immigration and emigration of a pelagic fish assemblage to seamounts in the Gulf of California related to water mass movements using satellite imagery. Marine Ecology-Progress Series, 49:11—20. Moyer, J. T., W. K. Emerson, and Michael Ross. 1982. Massive destruction of scleractinian corals by the muricid gastropod, Drupella, in Japan and the Philippines. Nautilus, 96(2):69-82. Wilson, E.C. 1988. The hermatypic coral Pocillopora at Cabo San Lucas, Mexico. Bull. So. California Acad. Sci., 87(2):79-83. Accepted for publication 12 September 1989. Edward C. Wilson, Curator, Section of Invertebrate Paleontology, Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, California 90007. Bull. Southern California Acad. Sci. 89(1), 1990, pp. 42-48 © Southern California Academy of Sciences, 1990 Prevalence of Larval Cestodes (Mesocestoides sp.) in the Western Fence Lizard, Sceloporus occidentalis biseriatus (Iguanidae), from Southern California Mesocestoides is a cosmopolitan genus of cyclophyllidean cestodes for which the complete life cycle is still unknown. There is a unique larval form, the tetra- thyridium, which is commonly found in mammalian, avian, and reptilian inter- mediate hosts, and which is readily infective to predatory definitive hosts (Schmidt 1986). Presumably, the first intermediate host is an arthropod; however, this has not been proven (Webster 1949). Tetrathyridia have been reported from a wide variety of North American lizards (Telford 1970; Dyer 1971; Mankau and Widmer 1977; Conn and Etges 1984; Goldberg 1985, 1987; McAllister 1988). These reports present infection prevalences for a species at a point and place in time. To our knowledge, infection prevalences over time have not been studied. Such data in addition to data on range, distribution, food habits and natural history of inter- mediate hosts are necessary if we are to understand the life cycle of this parasite. In this note we give data on yearly prevalences of Mesocestoides sp. in western fence lizard, Sceloporus occidentalis biseriatus, populations from southern Cali- fornia. Mesocestoides sp. has previously been reported in western fence lizards by Voge (1953), Specht and Voge (1965) and Telford (1970). Western fence lizards were collected by noosing from three localities in Los Angeles County, California: (1) Puente Hills, Whittier (34°01'N, 117°57'W; ele- vation 150 m); (2) junction California 39 and Crystal Lake Road, San Gabriel Mountains (34°18’N, 117°50'W; elevation 1584 m), and (3) Strawberry Peak off California 2, San Gabriel Mountains (34°17'N, 118°07’W; elevation 1878 m). Numbers of lizards collected by year and site are given in Table 1. The lizards were fixed in neutral buffered 10% formalin and stored in alcohol prior to ex- amination. Two of the 865 western fence lizards examined contained tetrathyridia of Me- socestoides sp. Sections of infected organs were embedded in paraffin, sectioned at 6 wm and stained with hematoxylin followed by eosin counterstain. Represen- tative specimens were deposited in the U.S. National Parasite Collection (Belts- ville, Maryland 20705, USA; accession numbers 80795, 80796). One infected lizard was an adult male (13.9 g; 76 mm snout—vent length (SVL)) collected 11 March 1989 at Strawberry Peak. In this lizard, white cysts containing tetrathyridia were attached to the stomach, intestines, testes, and liver. It was common to find two or three tetrathyridia within a single cyst. In all cases the holdfast was invaginated. Encapsulated tetrathyridia averaged 828 um in diameter and contained calcareous corpuscles (Fig. 1) which are characteristic of larval cestodes (Chitwood and Lichtenfels 1972). In addition, 16 tetrathyridia were found free in the coelomic cavity. The second infected lizard was collected in the Puente Hills 15 March 1989. It was an immature male (3.8 g; 47 mm SVL). Thirty-two tetrathyridia were found in the coelomic cavity; none were attached to organs. Prevalence of infection in western fence lizards examined here was 2/865 (0.2%). For 1989, the only year in which Mesocestoides sp. was found, prevalence in the 42 RESEARCH NOTES 43 Table 1. Yearly samples of western fence lizards. Whittier Crystal Lake Strawberry Peak 1971 85 74 — 1972 241 172 — 1986 45 67 — 1987 18 32 — 1988 7 — 15 1989 54 — 55 Totals 450 345 70 Puente Hills population was 1/54 (1.9%) and 1/55 (1.8%) for the Strawberry Peak population. Our data shows that Mesocestoides sp. is uncommon in the western fence lizard in southern California. Its absence in the years 1971-72, 1986-88 indicates it is an infrequent parasite in the western fence lizard populations in the above three study areas. Twenty-six species of North American lizards have been reported as hosts of Mesocestoides sp. tetrathyridia with an additional three species possibly containing them (Table 2). Sceloporus jarrovi represents a new host record. For a cosmo- politan genus, Mesocestoides sp. has been found in lizards in only a few locations; 7 states but only 15 counties. Reported prevalences ranged from O to 27. In addition to the absence of Mesocestoides sp. from Gambelia wislizenii, Mankau and Widmer (1977) reported its absence from three species of Sceloporus (Table 2). The higher prevalences are associated with iguanid lizards of arid habitats Fig. 1. Histological section through part of a tetrathyridium from the western fence lizard. Note convoluted border and scattered calcareous corpuscles (arrows) which are diagnostic of larval cestodes, 160x. 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Most of these lizards are opportunistic feeders which ingest various ar- thropods. There is no further development in lizards although normal develop- ment can resume should a lizard be eaten by a suitable definitive host (Specht and Voge 1965). Further investigation of these lizards would be appropriate. However, until more is known about the life cycle of Mesocestoides, lizards would perhaps best be considered as paratenic rather than intermediate hosts. Acknowledgments Weare grateful to T. A. Bienz for assisting with fieldwork and to W. W. Mayhew for supplying locality data. Literature Cited Benes, E. S. 1985. Helminth parasitism in some central Arizona lizards. Southwest. Nat., 30:467— 473. Babero, B. B., and F. R. Kay. 1967. Parasites of horned toads (Phrynosoma spp.), with records from Nevada. J. Parasitol., 53:168-175. , and D. Matthias. 1967. Thubunaea cnemidophorus n. sp., and other helminths from lizards, Cnemidophorus tigris, in Nevada and Arizona. Trans. Amer. Microsc. Soc., 86:173-177. Chitwood, M., and J. R. Lichtenfels. 1972. Identification of parasitic metazoa in tissue sections. Exp. Parasitol., 32:407-519. Conn, D. B., and F. J. Etges. 1984. Helminth parasites of Anolis carolinensis (Reptilia: Lacertilia) from southeastern Louisiana. Proc. Helm. Soc. Wash., 51:367-369. Dyer, W. G. 1971. Some helminths of the six-lined lizard, Cnemidophorus sexlineatus, in South Dakota. Proc. Helm. Soc. Wash., 38:256. Goldberg, S. R. 1985. Larval cestodes (Mesocestoides sp.) in the liver of the island night lizard, Xantusia riversiana. J. Wildl. Dis., 21:310-312. . 1987. Larval cestodes (Mesocestoides sp.) in the giant spotted whiptail, Cnemidophorus burti stictogrammus. J. Herp., 21:337. Harwood, P. D. 1932. The helminths parasitic in the Amphibia and Reptilia of Houston, Texas, and vicinity. Proc. U.S. Nat. Mus., 81:1-71. Mankau, S. K., and E. A. Widmer. 1977. Prevalence of Mesocestoides (Eucestoda: Mesocestoididea) tetrathyridia in southern California reptiles with notes on the pathology in the Crotalidae. Jap. J. Parasitol., 26:256-259. McAllister, C. T. 1988. Mesocestoides sp. tetrathyridia (Cestoidea: Cyclophyllidea) in the iguanid lizards, Cophosaurus texanus texanus and Sceloporus olivaceous from Texas. J. Wildl. Dis., 24: 160-163. Pfaffenberger, G. S., T. L. Best, and D. de Bruin. 1986. Helminths of collared lizards (Crotaphytus collaris) from the Pedro Armendariz lava field, New Mexico. J. Parasitol., 72:803-806. Schmidt, G. D. 1986. Handbook of tapeworm identification. CRC Press, Boca Raton, Florida, 675 pp. Specht, D., and M. Voge. 1965. Asexual multiplication of Mesocestoides tetrathyridia in laboratory animals. J. Parasitol., 51:268—272. Telford, S. R., Jr. 1964. A comparative study of endoparasitism among some southern California lizard populations. Ph.D. Dissertation, University of California, Los Angeles, 260 pp. 1970. A comparative study of endoparasitism among some California lizard populations. Amer. Midl. Nat., 83:516-554. Voge, M. 1953. New host records for Mesocestoides (Cestoda: Cyclophyllidea) in California. Amer. Midl. Nat., 49:249-251. Webster, J. P. 1949. Fragmentary studies on the life cycle of the cestode Mesocestoides latus. J. Parasitol., 35:83—90. Accepted for publication 26 July 1989. 48 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES Stephen R. Goldberg, Department of Biology, Whittier College, Whittier, Cali- fornia 90608 and Charles R. Bursey, Department of Biology, Pennsylvania State University, Shenango Valley Campus, 147 Shenango Avenue, Sharon, Pennsyl- vania 16146. DESERT ECOLOGY 1986 A Research Symposium Twelve papers from the Desert Studies Consortium at the Academy 1986 An- nual Meeting comprise a new publication now available. Subjects include the Coachella Valley Preserve, Water Rights, Late Pleistocene Mammals, Chemical Defense Patterns of Certain Desert Plants, Off-Road Vehicle disturbances, Desert Pupfish, Plant Communities, Desert Bats, etc. Send name, address, and $29.00 per copy in check made out to The Southern California Academy of Sciences, 900 Exposition Blvd., Los Angeles, CA 90007. 3 5183 00317 7753 INSTRUCTIONS FOR AUTHORS The BULLETIN is published three times each year (April, August, and December) and includes articles in English in any field of science with an emphasis on the southern California area. Manuscripts submitted for publication should contain results of original research, embrace sound principles of scientific investigation, and present data in a clear and concise manner. The current AIBS Style Manual for Biological Journals is recommended as a guide for contributors. Consult also recent issues of the BULLETIN. 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Such illustrations along with a brief caption should be sent to the Editor for review. PROCEDURE All manuscripts should be submitted to the Technical Editor, Jon E. Keeley, Biology Department, Occidental College, 1600 Campus Road, Los Angeles, California 90041. Authors are requested to submit the names, addresses and specialities of three persons who are capable of reviewing the manuscript. Evaluation of a paper submitted to the BULLETIN begins with a critical reading by the Editor; several referees also check the paper for scientific content, originality, and clarity of presentation. Judgments as to the acceptability of the paper and suggestions for enhancing it are sent to the author at which time he or she may be requested to rework portions of the paper considering these recommendations. The paper then is resubmitted and may be re-evaluated before final acceptance. Proof: The galley proof and manuscript, as well as reprint order blanks, will be sent to the author. He or she should promptly and carefully read the proof sheets for errors and omissions in text, tables, illustrations, legends, and bibliographical references. He or she marks corrections on the galley (copy editing and proof procedures in Style Manual) and promptly returns both galley and manuscript to the Editor. Manuscripts and original illustrations will not be returned unless requested at this time. All changes in galley proof attributable to the author (misspellings, inconsistent abbreviations, deviations from style, etc.) will be charged to the author. Reprint orders are placed with the printer, not the Editor. CONTENTS Late Quarternary Nonmarine Mollusca from Kokoweef Cave, Ivanpah Mountains, California By Barry Roth and Robert E. Reynolds Movement and Habitat Selection in Tagged Rock Crabs (Cancer anten- narius) in Intertidal Channels at James V. Fitzgerald Marine Life Ref- uge, California By Robert T. Breen and Mary K. Wicksten Status and Management of Shoshone Pupfish, Cyprinodon nevadensis sho- shone (Cyprinodontidae), at Shoshone Spring, Inyo County, California By Daniel L. Castleberry, Jack E. Williams, Georgina M. Sato, Todd E. Hopkins, Anne M. Brasher, and Michael S. Parker Comparative Photosynthesis, Water Relations, and Nutrient Status of Burned, Unburned, and Clipped Rhus /aurina after Chaparral Wildfire By Roy Stoddard.and Stephen D. Davis “2 SS eee Research Notes Mass Mortality of the Reef Coral Pocillopora on the South Coast of Baja California Sur, Mexico’ (By Bdward Ge Wilson teak oe eh Oe sh eae Prevalence of Larval Cestodes (Wesocestoides sp.) in the Western Fence Lizard, Sceloporus occidentalis biseriatus (Iguanidae), from Southern California By Stephen R. Goldberg and CharleseREBUrsey nek ae SESE IOS as 0 AS ae SR ee cies Lee | IBRARY iQ - 2 (996 wv (ORK ' 4: GARDEN 10 19 26 39 42 COVER: Fragment from a dead, heavily encrusted corallum of Pocillipora sp. Compare with cover and page 79 of volume 87 #2. Photo by Edward C. Wilson. (See Page 39.)