s 591.7 Nllfsc 2001 A Faunal Survey of the Centennial Valley Sandhills, Beaverhead County, Montana STATE DOCUMENTS COLLECTION uuM 0 4 2001 Prepared for: wo^^sis Hel^'^l^"^' HELENA, MONTANA 59620 U.S. Bureau of Land Management and U.S. Fish and Wildlife Service Prepared by: Paul Hendricks and Michael Roedel April 2001 # i U' MONTANA [y^j Natural Heritage ^^^^ Program MONTANA STATE LIBRARY 3 0864 0015 5801 7 A Faunal Survey of the Centennial Valley Sandhills, Beaverhead County, Montana © 2001 Montana Natural Heritage Program State Library Building • P.O. Box 20 1 800 • 1 5 1 5 East Sixth Avenue • Helena, MT 59620- 1 800 • 406^44-3009 USBLM Agreement Number 1 422E 930A 9600 1 5 U.S. Bureau of Land Management- Dillon Field Office 1005 Selway Drive Dillon, MT 59725 USFWS Agreement Number 1 448-601 8 1 -99-J976 U.S. Fish and Wildlife Service Red Rock Lakes National Wildlife Refuge Box 1 5, Monida Star Route Lima, MT 59739 This document should be cited as follows: Hendricks, R, and M. Roedel. 2001 . Afaunal survey of the Centennial Valley Sandhills, Beaverhead County, Montana. Report to the U.S. Bureau of Land Management and U.S. Fish and Wildlife Service. Montana Natural Heritage Program, Helena. 44 pp. Executive Summary The Montana Natural Heritage Program, in partnership with Red Rock Lakes National Wildlife Refuge and the Bureau of Land Management — Dillon Field Office, has completed a terrestrial faunal survey of the Centennial Valley Sandhills of southeastem Beaverhead County. No previous comprehensive animal survey has been conducted in these Sandhills, the second largest sandhills complex in Montana. This work compliments previous studies of the plants and vegetation dynamics in the Centennial Sandhills by associating a number of animal species to specific physical features and successional stages at this site. Maintaining the current diversity of animals will depend upon the controlled introduction of disturbance processes such as fire and grazing to create a mosaic of vegetation in various stages of succession. Disturbances should be conducted at scales appropriate for the entire Centennial Valley as well as the Sandhills specifically. The Sandhills support a diverse array of vertebrates and invertebrates with affinities to shrub-steppe habitats more representative of the entire Centennial Valley. Eighteen mammal species, 29 bird species, 3 amphibian and reptile species, 4 tiger beetle species, and 14 butterfly and skipper species were documented in the Sandhills during the 1 999 survey. Three state mammal species of special concem were documented: Preble's Shrew (Sorex preblei). Black-tailed Jackrabbit {Lepus californicus), and Great Basin Pocket Mouse {Perognathus parvus). Preble's Shrew is collectively the twentieth state record and the first for Beaverhead County, Black-tailed Jackrabbit is the fourteenth state record, and Great Basin Pocket Mouse is the first record for the Centennial Valley and the first record for Montana since 1 96 1 . The shrew appeared to be widespread at low density, the jackrabbit was observed in stabilized sandflats with scattered sagebrush cover, and the pocket mouse was associated with scattered sagebrush in stabilized low-dune habitat. A fourth species of special concem, Pygmy Rabbit (Brachylagus idahoensis) was not seen in 1 999 but has been reported recently in the Sandhills in stands of dense big sagebrush. Three Montana Partners In Flight (PIF) Priority 11 bird species (Sage Thrasher, Brewer's Sparrow and Grashopper Sparrow) were present daily. The thrasher was associated only with tall and mature big sagebrush, the Brewer's Sparrow also was associated with sagebrush, but in a variety of size classes. Grasshopper Sparrow, a rare transient species in the Centennial Valley, was present in a localized site of grassy habitat with little shrub cover. Defensive behavior by a pair of Long-billed Curlews, and discovery of an old nest of Ferruginous Hawk, both PIF Priority II species, indicated these species bred in the Sandhills. Two tiger beetle species, Cicindelaformosa and C. decemnotata, were common in sandy blowouts or other early-seral sites, but in different parts of the Sandhills. C. tranquebarica, was localized on or near sites where sandy or pebbly soil was somewhat moist. C. longilabris, was encountered only twice in sandy sites with moderate shrub and grass cover. The rare Idaho Dunes Tiger Beetle (C arenicold), endemic to Idaho and present 64 km (40 miles) south in the St. Anthony Dunes (Fremont County), was not encountered but may occur. As opportunities present themselves, additional surveys of selected groups/species with specific habitat or food needs (small mammals, songbirds, ground beetles, butterflies) may be warranted. In addition, surveys of all animal groups should be conducted throughout the Centennial Valley to identify the significance of the sandhill-associated fauna to the entire valley system. Acknowledgements We are especially grateful to Jim Roscoe (BLM Dillon Field Office) and Danny Gomez (Red Rock Lakes National Wildlife Refuge) for their interest and support of this project on BLM and USFWS lands. Through their guidance and on-the-spot orientation, field work was more productive than it might otherwise have been. We thank Stan Vlahovich (Montana DNRC) and Bill and Judy Staudenmeyer for permission to visit state and private lands, respectively, under their steward- ship. Tim Swanson(TNC) provided useflil landowner contacts for the Centennial Valley Sandhills area. For help with specimen identification we thank Dave Dyer (University of Montana: shrews), Kerry Foresman (University of Montana: shrews), Mike Ivie (Montana State University: tiger beetles). Will Kerling (Missoula: butterflies), and Steve Kohler (Montana DNRC: butterflies). For permission to examine museum collections of tiger beetles we thank Frank Merikel (University of Idaho) and Rich Zack (Washington State Univer- sity). Ryan Rauscher (Montana FWP) provided records of Pygmy Rabbit in the sandhills area, and Dennis Flath (Montana FWP) shared his knowl- edge of small mammal records (especially shrews and pocket mice) from the Centennial Valley and elsewhere in Beaverhead County. We benefited from the assistance of Montana Natural Heritage Program staff, including Cedron Jones who produced the maps for this report, and Martin Miller who entered field data into Heritage Program databases. John Carlson, Joy Lewis, and Sue Crispin made many useful editorial suggestions on earlier versions of this report, making the final product more readable. We are also indebted to Jim Roscoe (BLM), Danny Gomez (USFWS), Randy Gazda (USFWS), and Brian Martin (TNC) for their comments on a near- final draft that helped rectify any factual errors or oversights. Katrina Scheuerman (Montana State Library, NRIS) patiently guided the transformation of this report from an ugly draft into a professional final product. We thank them all. Table of Contents I. Introduction 1 II. Study Area 2 Cenntennial Valley 2 Centennial Sandhills 2 III. Methods 5 Mammals 6 Birds 7 Amphibians and Reptiles 7 Insects 7 IV. Results 9 Mammals 9 Birds 13 Amphibians and Reptiles 13 Insects 14 V. Discussion 16 VI. Recommendations and Conclusions 18 Sagebrush Manipulation 19 Fire 19 Livestock Grazing 19 Concluding Remarks 20 Future Work 20 VII. Literature Cited : 22 Figure 1. Centennial Sandhills study area 3 Figure 2. Photograph of sparsely vegetated blowout 4 Figure 3. Photograph of stabilized dunes 4 Figure 4. Photograph of drift fence array 8 Figure 5. Photograph of a tiger beetle Cicindela formosa 8 Table 1. Total trapping effort 6 Table 2. Standard skull measurements from shrews {Sorex) 10 Table 3. Skulls recovered from raptor pellets 12 Table 4. Counts of tiger beetles {Cicindela) 15 Appendix 1 . Global and State Rank Guidelines Appendix 2. Small mammal species of special concern from the Centennial Sandhills Appendix 3 . Descriptions of trapping locations Appendix 4. Small mammals captured on live trap/snap lines Appendix 5. Small mammals captured on pitfall trap lines Appendix 6. Small mammals captured at drift fence arrays Appendix 7. Mammal, amphibian, and reptile species documented in the Centennial Sandhills Appendix 8. Bird species documented Appendix 9. Tiger Beetles and butterflies documented iii Introduction Extensive sandhills are rare in Montana. The state's 2 major areas of sandhills lie at extreme opposite comers of the state - the largest in northeastem Montana near the Medicine Lakes in Sheridan County, and the second largest in south- westem Montana in the Centennial Valley of Beaverhead County — both partially within National Wildlife Refuges. While the flora of these areas has been studied recently (Cooper et al. 1999, Lesica and Cooper 1999, Heidel et al. 2000), the fauna has not been as well docu- mented, especially that of the Centennial Sandhills. Sandhills terrain is a product of wind and sand. Sandhills occur in wind corridors where blowing sand might be ftinneled, in the windward foothills of mountain ranges, and in areas where wind speeds are no longer sufficient to move sand any farther or where improved growing conditions increase the probability of dune stabilization by plants. Sandhills are characterized by erodible, well-drained soils that are very susceptible to disturbances such as fire, grazing, and burrowing (Knight 1 994). Sandhills often occur as isolated patches across a regional landscape, and contrib- ute significantly to local biodiversity by supporting distinctive species and communities. Because disturbance can easily alter these sites, sandhill complexes support vegetation in various stages of succession, often harboring early-succession species and communities that are rare at local, regional or global scales and dependent on distur- bance for survival (Lesica and Cooper 1999). For example, the Centennial Sandhills support 4 rare plant species that are restricted to early succession sites (Lesica and Shelly 1991, Lesica and Cooper 1999): Idaho painted milkvetch (Astragalus ceramicus var. apus), Idaho pale evening-primrose (Oenothera pallida var. idahoensis), Fendler's cat's-eye (Cryptantha fendleri), and sand wildrye (Elymusflavescens). Sandhills habitats also support animal species of limited distribution, some of which (usually inverte- brates) are sand-obligate species (Rumpp 1967, Knisley 1979, Rust 1986). The flora and fauna of Beaverhead County, which includes the Centennial Sandhills, have affinities to the Great Basin (Dom 1978, Lesica et al. 1984, Hofl&nann and Pattie 1968, Hoffinann et al. 1969b). These natural similarities distinguish this sandhill complex from the Medicine Lake Sandhills in northeastem Montana. Five mammal species on the state special concern or watch lists are limited to southwestern Montana (Black-tailed Jackrabbit, Pygmy Rabbit, Wyoming Ground Squirrel, Great Basin Pocket Mouse, Western Spotted Skunk), and two other species of concern (Preble's Shrew, Merriam's Shrew) are associated with habitats found in the Centennial Valley, especially sagebrush-steppe (Armstrong and Jones 1971, Comely etal. 1992). In addition, the rare Idaho Dunes Tiger Beetle (Cicindela arenicola), currently known only from Idaho, occurs in the St. Anthony Dunes of Fre- mont County (Rumpp 1967, Logan 1995, Pearson et al. 1997) only 64 km (40 miles) south of the Centennial Valley Sandhills. Because the valley is remote and near the edge of several species' distributions, and has not been well surveyed, there is good potential to find this or other species new to Montana, as well as, an opportunity to document significant range exten- sions of more common species. This is especially true for small mammal and tiger beetle communi- ties, since these groups contain species that are habitat specific and/or are relatively obscure and pooriy documented in Montana, particularly in sandhills and shrub-grassland habitats. Because of the very limited distribution of sandhills habitat in Montana and the distinctive nature of its plants and animals, documenting the fauna is an important first step toward effective management of the biological diversity associated with these habitats. The objectives of this study were to: 1 ) document the vertebrate species present in the Centennial Sandhills; 2) document selected groups of invertebrates (especially tiger beetles); 3) identify relationships between species distribu- tions, stages of vegetation succession and sandhills physiognomy; and 4) provide information to assist managers in maintaining the faunal diversity of this unique area. Study Area Centennial Valley The Centennial Valley of Beaverhead County, located about 80 km west of Yellowstone National Park, is a relatively undeveloped area of Montana and a biodiversity "hot spof (Povilitis and Mahr 1998). The valley is about 75% public and 25% private ownership. Public lands include units administered by the U. S. Fish and Wildlife Service, U. S. Bureau of Land Management, U. S. Forest Service, and State of Montana. Live- stock grazing and livestock-related agriculture are the principal land uses. The valley is an east- west trending basin about 60 km in length of 1 600 km^ within the "Southwest Montana Intermontane Basin and Valleys" subsec- tion of the Beaverhead Section (Nesser et al. 1997). The climate is cold and continental, with warm dry summers and cold dry winters, and is characterized by 22-50 cm of precipitation, of which 10% falls as snow. The steep-sloped Centennial Mountains form the valley's southem boundary, with several summits between 2850 and 3087 meters in elevation. The Continental Divide runs along the crest of the Centennial Mountains, which form the north rim of the broad Snake River basin to the south. The less rugged Gravelly and Snowcrest ranges lie to the north of the valley, each with elevations exceeding 3 1 80 m. This broad, flat-bottomed basin was likely formed both by^ erosion and by downfaulting which has oc- curred here since the Miocene (Alden 1953). The gradient of the valley floor is very slight, and there is little evidence of downcutting at the outflow of the Red Rock Lakes (Banko 1 960). The valley supports over 700 plant species and at least 20 major vegetation community types, including the rare three-tip sagebrush-Idaho fescue {Artemisia tripartita-Festuca idahoensis) type that forms the climax vegetation of the Centennial Sandhills (Lesica and Cooper 1 999). Over 26 1 bird species have been documented for the valley, including the Trumpeter Swan (Cygnus buccina- tor), which Red Rock Lakes National Wildlife Refuge was established to protect. The valley also hosts one of the two remaining native populations of Montana Arctic Grayling (772ywo//M5 arcticus montanus), and one of three known native populations of Lake Trout {Salvelinus namaycush). In addition, the eastern portion of the valley offers a movement corridor and year- round habitat for larger carnivores such as Lynx {Felis lynx). Wolverine {Gulo gulo). Gray Wolf {Canis lupus), and Grizzly Bear ( Ursus actos horribilis). Centennial Sandhills The Centennial Sandhills, which lie in the northeast comer of the Centennial Valley, are a unique feature of the Greater Yellowstone Ecosystem. They form a band approximately 2-3 km wide and 14 km long (between 44°40'N, 1 1 1 °42' Wand 44°42'N, 1 1 1°49'W) and cover about 3200 ha in 1 8-20 legal sections north of Lower and Upper Red Rock lakes. The sandhills consist of small and generally stabilized dunes created by sands deposited probably during the late Pleistocene. They are in various stages of activity, with the most active and tallest lying north of Lower Red Rock Lake (in Tl 3S R2W) and the lower and most stable dunes present in the eastern portion of the sandhills (in T 1 3 S R 1 W), east of Tepee Creek (see Figure 1). Average elevation of the sandhills is about 2030 m. The Sandhill vegetation is a mixture of succes- sional types (Lesica and Cooper 1999) dominated by shrubs (big sagebrush, ^rtemw/o tridentata; u it ^■?! a U o V u a. ■a J3 H o h. U v> > R « > u ■o s ■** M *ja ■e s cs %i MM .9 o a 01) - > -S 2 <» 5 u- P IS > J w 5 2 £ m D ^ (A a. DDDDD a k^ c ant ID t ~ K £ O I 1 [If .K,'-. Figure 2: Sparsely vegetated blowout in the West Hills. Individual is netting the tiger beetle Cicindela formosa. Figure 3: Stabilized dunes with shrub and grass cover in the West Hills 4 three-tip sagebmsh, A. tripartita; common rabbitbrush, Chrysothamnus nauseosus; green rabbitbrush, C viscidiflorus), forbs (silvery lupine, Lupinus argenteus; silky lupine, L sericeus; brittle prickly-pear, Opuntiafragilis; slender-flowered scurf-pea, Psoralea tenuiflora), and grasses (thick-spiked wheatgrass, ^gro/7yra« dasystachyum; Idaho fescue, Festuca idahoensis; prairie junegrass, Koeleria cristata; needle-and-thread, Stipa comata). Sandhill sites occur in 3 classes based on topography and effects of sand movement: lower-slope erosion blowouts, (Figure 2), upper-slope deposition, and stabilized (both upper and lower slopes), (Figure 3). Lesicaand Cooper (1999) identified three successional stages (early-, mid-, and late-seral) from the previous classes. During our 1 999 field work we used the Lesica- Cooper succession classification as a reference for documenting animal detections. We found that four physiognomic types (inter-dune trough, dune crest, low dunes, and sand flats) were also usellil for our purposes in categorizing trapline and driftfence locations (see Appendix 3 ). Inter-dune troughs were elongate depressions between parallel dune ridges of the West Hills. They were equivalent to the stabilized class but often sup- ported denser stands of sagebrush than were found on dune slopes; troughs also covered more extensive and relatively flat terrain. Dime crests were equivalent to either deposition or stabilized classes, but sometimes occurred as lengthy and wide ridge tops that gently sloped along the main dune axis. The low dunes category was generally equivalent to the stabilized class, but contained small sparsely vegetated sandy depressions intermixed among dune swales; this category was most extensive east of Tepee Creek. Sand flats were extensive expanses of low-relief terrain supporting sagebrush and grasslands in various degrees of cover; an area roughly 6 km wide east- to-west bracketing Tepee Creek fit into this physiognomic category. Survey Methods We visited the Centennial Sandhills four times during the summer of 1999: 24-28 May, 28 June- 3 July, 26-30 July, and 20-23 September Daily temperature minima and maxima were recorded with a Taylor minimum-maximum thermometer to characterize weather conditions during the periods of daily sampling. We employed a variety of techniques to sample a diverse array of animal groups. In some cases we actively searched for animals or their spoor, while in other cases we used a variety of passive trapping methods. These are described below for each animal group. In many cases we attempted to systematize sampling procedures, but opportunistic sampling was also employed to increase our survey coverage of the Sandhills. We also searched the Heritage data- bases, pubhshed and gray literature, and museum records for documented historical occurrences of target species, especially for mammals, amphib- ians, reptiles, and tiger beetles. Tiger beetle collections at the University of Idaho and Wash- ington State University were examined for speci- mens collected in Beaverhead County and adja- cent localities in Idaho. Common and/or scientific names in tables and text throughout follow Jones et al. ( 1 986) for mam- mals, American Ornithologists' Union (1998) for birds, Stebbins ( 1 985) for amphibians and rep- tiles, Pearson et al. ( 1 997) for tiger beetles, and Opler ( 1 999) for diurnal butterflies. Statistical analyses, where used, follow standard procedures presented in Sokal and Rohlf ( 1 98 1 ). Statistical significance of tests is assumed when p < 0.05, although we recognize that statistical significance is not the same thing as biological significance. Throughout the text "West Hills refers to that portion of the sandhills west of Tepee Creek and "East Hills" is that portion of the sandhills east of Tepee Creek (see Figure 1 ). Mammals We documented large and medium-sized mam- mals (lagomorphs or larger) whenever encoun- tered, but made no attempt to sample them systematically. We inspected dens for evidence of recent or current occupancy and sampled prey remains if available, and we traversed the densest and most extensive stands of big sagebrush {Artemisia tridentata) looking for sign (pellets, burrows) of Pygmy Rabbit (Brachylagus idahoemis). When traversing areas of moderate to dense cover, two observers followed separate routes to increase the likelihood of flushing cotton- tails or jackrabbits. Our intensive small mammal sampling involved systematic trapping and examination of r^tor pellets for skulls. We deployed 3 trap types (live traps, snap traps, and pitfall traps) along line transects or drift arrays to sample small mammals. Different species of small mammals are more or less likely to be captured using any single trapping method (Jones etal. 1996, Allen etal. 1997), so we used a variety of trapping techniques to increase the probability of detecting the complete small mammal fauna Shrews (Soricidae) in particular are most likely to be captured using pitfall traps. We placed trap transects selectively (Appendix 3) to sample a variety of terrain repre- senting different succession classes, rather than distributing them randomly or systematically Total trapping effort included 2772 live and snap trap nights and 8380 pitfall trap nights (Table 1 ). We placed both live traps (folding Sherman traps 7.6 X 8.9 X 22.9 cm, model LFATDG) and snap traps (Museum Special) together on transects of 30 stations, with stations spaced approximately 10 m apart in roughly a straight line. One live trap and 2 snap traps were placed at each station within one meter of the station. Live traps were baited with a commercial seed mixture of millet, cracked com, and sunflower seed; a small wad of polyester fiber material was placed in the back of traps to provide insulation for potential trapped animals. Snap traps were baited with a mixture of rolled oats and peanut butter. Traps were placed late on one day and left in place for 3 or 4 nights, with daily morning visits to document captures. We closed snap traps during the day to minimize capture of diurnal birds and recaptures of chip- munks {Eutamias minimus), live traps remained open. Atotalof 11 live/snap trap transects were run during summer (Figure 1 ), 3 during each visit except two in September During the last 2 sample periods (late July, late September) only snap traps were deployed, as live traps were more time consuming to use and captures in live traps were very low. We established 6 pitfall transects (Figure 1 ) on 25 and 26 May. Pitfall traps used were coffee cans (15x17 cm) buried with the rim flush to the ground surface. Pitfall transects consisted of 1 0 cans, one per station, placed in a relatively straight line approximately 30 m apart. We checked pitfall traps daily when we were at the site and left them TABLE 1 . Total trapping effort (trap nights) in the Centennial Sandhills, Beaverhead County, Montana in 1999. Sampling period Live trap Snap trap Pitfall (transect) Pitfall (drift array) Period 1 (late May-Jun) 300 600 2020 384 Period 2 (late Jun-Jul) 270 522 1740 348 Period 3 (late Jul-Sep) 720 3240 648 Period 4 (late Sep) 360 Total trap nights 570 2202 7000 1380 in place between sample periods until retrieved on 22 September. We also installed 3 drift fence pitfall arrays (Figure 1 ) on 27 May. Drift fence arrays increase the area effectively sampled and generally are more pro- ductive than lone pitfall traps (Com 1994, Jones et al. 1 996), but they require additional materials and are more time consuming to install. Drift arrays were arranged with three 2.5 m long masonite fins radiating out fi"om a central pitfall can (Figure 4). Masonite fins were held in place with wooden lath. An additional pitfall can was placed at the end of each fin. Thus, 4 pitfall cans were associated with each drift fence array. Drift fence arrays were checked following the protocol for pitfall transects and left in place until retrieved on 22 September. Captured mammals were identified to species, when necessary using keys in Hoffmann and Pattie (1968) and Clark and Stromberg(1987) as well as more detailed literature. Individuals were weighed and measured, and sexed if possible. Vouchers of some species (especially shrews) were preserved for additional study and determi- nation by Dr. Kerry Foresman, and deposited in the Philip L. Wright Vertebrate Museum at the University of Montana. We also routinely searched for regurgitated raptor pellets below wooden fence posts and other potential perches in the sandhills. Pellets were collected and dissected for small mammal skulls and other vertebrate remains. Small mammals recovered fi^om pellets were identified to species based on skull charac- teristics. Birds We conducted no systematic counts of birds, but maintained daily lists of bird species detected during other work, recording the area where they where detected, and any additional striking behavior or habitat notes (such as singing or association with a particular habitat feature). Although we conducted no nest searches, we documented all nests located, recording stage of nesting, nest contents, and nest position. Amphibians and Reptiles We found virtually no wetland areas in the Sandhills during our visits, and so devoted little time to active searches for amphibians. We identified itogs by call and visually as we encoun- tered them. We sought reptiles as we drove roads and traversed the study area during other activi- ties. Systematic sampling was limited to the earlier- described pitfall transects and drift fence arrays, which are standard sampling techniques for these vertebrate groups (Com 1994), especially for adult salamanders and lizards that may be over- looked using other techniques. Vouchers were collected and deposited in the herpetological collection at the Idaho Museum of Natural His- tory, Idaho State University. Insects We focused our insect sampling on 2 groups, tiger beetles (genus Cicindela) and diurnal butterflies (Lepidoptera: Papilionoidea and Hesperioidea). We chose these groups because they are visible and often tied to local habitat conditions. Cap- tured individuals were subdued with ethyl acetate in a killing] ar and pinned for later examination, or identified in the field. We sampled figer beetles (Figure 5) in two ways: active searching/sweep-netting, and pitfall trap- ping. As with many other small terrestiial organ- isms, tiger beetles are readily captiared in pitfall ti-aps (Morrill etal. 1990, Clark and Blom 1992, Berghe 1992), and drift fences improve capture success (Knisley and Schultz 1997). Because our primary objective was to document habitat use and species presence, rather than relative abun- dance, we did not place preservative in the pitfall cans to kill insects. Nevertheless, our pitfall traps were successfijl in capturing about 200 individual tiger beeties. During our first 3 visits to the Sandhills, we docu- mented relative abundance at 4 sites by walking 1 00 m road ti-ansects and counting numbers of each species, noting habitat adjacent to the road. • '%r^ A>% Figure 4: Drift fence array showing radiating fins around a central pitfall can, with an additional pitfall can at the end of each fin. Figure 5: The tiger beetle Cicindelaformosa, the common species in West Hills blowouts. time of day, and air temperature (tiger beetles are very temperature sensitive: Knisley and Schlutz 1997). We also noted mating or nesting behavior, and documented general habitat features and succession class of sites where beetles were encountered. Tiger beetle specimens were identified under a dissecting microscope using the key developed by Willis (1968) and descriptions in other sources, such as Knisley and Schultz ( 1 997) and Leonard and Bell ( 1 999). Dr. Mike Ivie verified identifica- tions of voucher specimens for all species docu- mented; vouchers were deposited in the Entomol- ogy Museum at Montana State University. We sampled diurnal Lepidoptera (butterflies and skippers) only on 29 and 30 July, during the peak of the summer Because our survey did not focus on this insect group, the sampling was brief and opportunistic, and the list we generated is only preliminary. No effort was made to estimate relative abundance. Species were netted and identified in the field using Opler ( 1 999). Notes on habits and habitat were made at the time of capture. Vouchers were collected and papered for later examination and determination by state experts Steve Kohler and Will Kerling (Missoula). Results Between late May and late September 1999 our surveys documented 18 species of mammals, 29 species of birds, two amphibian and one reptile species, four species of tiger beetles, and 14 species of diurnal butterflies (Appendices 7-9). Most of these were found both east and west of Tepee Creek, but there were some noticeable differences in distribution patterns, discussed below. Mammals Bats: We did not sample for bats, since the sandhills offer few sites that would concentrate activity, and there appears to be few suitable sites for roosting or raising young. However, bats probably forage over the Sandhills during summer Few bat species have been documented from the Centennial Valley; only Little Brown Bat {Myotis lucifugus) is on the refuge list. However, Townsend's Big-eared bat (Plecotus [-Corynorhinus] towmendii), a Montana species of special concern, has also been docu- mented on the reflige (Hoffinann et al. 1 969a); 2 specimens were collected on 25 August 1965 (UMZ 12776 and 12777; University of Montana Philip L. Wright Vertebrate Museum). Shrews: We captured shrews only in pitfall traps (Appendices 5 and 6) at the low rates (0.30/1 00 trap nights) not unusual for shrews (Kirkland et al. 1997). However, success in the drift arrays (0.80/ 1 00 trap nights) was 4 times greater than for pitfall transects (0.20/ 1 00 trap nights), even though there were only one fifth as many trap nights. This suggests that drift arrays may be the most suitable method for fiiture monitoring of shrew abundance and habitat use in the Sandhills. We captured 25 individual shrews, including 8 Dusky Shrews {Sorex monticolus), 6 Masked Shrews (S. cmereus), and 2 Preble's Shrews (5. preblei). Nine shrews were not identifiable to species (they were either Masked or Preble's) because skulls were incomplete and did not have enough measurable traits for reliable determina- tion. However, palatal length and interorbital breadth measurements (Table 2) indicate at least some of the unidentified shrews were probably Preble's (Hofl&nann et al. 1 969b, Hofimann and Fisher 1978, Tomasi and Hoffinann 1984, Long and Hoffinann 1992). Our collection of Preble's Shrew is new for the Centennial Valley and Beaverhead County, the nearest previous collection being 40 km to the northeast at Quake Lake in Gallatin County ( 1 968), Preble's Shrew is a species of concern in Montana (Appendix 2). Our collections of Dusky Shrew {Sorex monticolus) and Preble's Shrew {S. preblei) are new species records for the Refuge. TABLE 2. Standard skull measurements from shrews {Sorex) collected in the Centennial Sandhills, Beaverhead County, Montana in 1999. All measurements (in mm) were made with a microscope fitted with an optical micrometer. Sample size varies where skulls are Incomplete. Species n Palatal length Condylobasal length Interorbital breadth S. cinereus 4 6.6, 6.7, 6.6, 6.6 15.84,16.08 2.7,2.7,2.8,2.6 S. preblei 2 5.9,6.0 14.16,14.52 2.45, 2.6 S. species 3 5.8, 5.9, 6.2 no measurements 2.4, 2.6 The majority of shrews — 72% ( 1 8 of 25 cap- tured) — were trapped in the East Hills. Equal numbers of shrews were captured on pitfall transects in the West and East Hills (7 individuals each), even though there were twice as many trap nights of effort in the West Hills (4680 vs. 2320). This suggests that shrews are much more abundant in the southern areas of the East Hills. This pattem also holds for the drift array results (Appendix 6). The 2 confirmed Preble's Shrews came from pitfall line 3, and the 3 potential Preble's speci- mens from drift array 3 in the East Hills and pitfall line 4 in the West Hills. These results suggest that this rare shrew may be widespread at low density in the Sandhills. There was no clear correlation between pitfall trap captures and habitat types. More shrews were captured on lines with moderately dense shrub cover than where shrub cover was sparse (see Appendix 3). The difference, however, was not statistically significant (binomial probability P= 0.338), partly because of small sample size. Complicating the situation were the drift array results: no shrews were captured in array 1 (a blowout with sparse cover) but 6 were captured in array 3 (also a blowout with sparse cover), and 5 in array 2 (low depression with sparse cover). Five of 6 Masked Shrews (5. cinereus) were caught in sparse shrub/grass cover, but total captures were too few to identify with confidence any microhabitat association. The 2 confirmed and 2 of the potential Preble's Shrews were also captured in sparse shrub/grass cover Dusky Shrew (S. monticolus) captures were evenly divided between habitats with moderate and sparse cover The lack of obvious microhabitat association, especially for Masked Shrew, has been noted at other sandhills and shrub-steppe locations (Wrigley 1974, Kirklandetal. 1997). In other areas, each species has been found in shrub- steppe habitats (Ports and George 1990, Kirkland etal. 1997, Sutter etal. 1999), sometimes occur- ring together in the same habitats as they do in the Sandhills. However, Dusky and Masked shrews are often considered montane species associated with mesic habitats. Lagomorphs: We encountered 2 Lagomorph species during our surveys. White-tailed Jackrab- bit {Lepus townsendii) was seen only once, on 2 1 September in the West Hills, but fresh remains were also foimd in the West Hills on 25 May and in the East Hills on 30 July, indicating a wide- spread distribution but at relatively low density. Jackrabbits are apparently less common now in the Centennial Valley than they were 10-15 years ago (D. Gomez, personal communication). Black- tailed Jackrabbit was seen once, on 27 July west of Tepee Creek in sparse low-stature sagebrush (T13S,R1W,S19SW). This species has not yet been reported on Refuge lands, but could occur in the Sandhills portion of the Refuge. Davis ( 1 937) 10 first reported the species in Montana, but there have been few additional records (13 total in the Heritage databases, including one in 1969 from an unknown locality in the Centennial Valley). We failed to detect Pygmy Rabbit in our survey, but there is a recent record ( 1 9 August 1 997) from the West Hills (T13S,R2W,S14SW)ina stand of dense big sage (Rauscher 1997, personal communication). Both Black-tailed Jackrabbit and Pygmy Rabbit may have entered the state follow- ing an increase in sagebrush cover in southwestern Montana since the late nineteenth century (Hofl&nannetal. 1 969b, Amo and GrueU 1983, Lesica and Cooper 1 997), as there are no Mon- tana records for either species prior to 1 9 1 8. Both are species of special concern in Montana (Appendix 2). Rodents: We captured 137 individuals of 6 rodent species (Appendices 4-6): 1 9 Least Chipmunk {Tamias minimus), 17 Northern Pocket Gopher {Thomomys talpoides), 6 Great Basin Pocket Mouse (Perognathus parvus), 57 Deer Mouse (Peromyscus maniculatus), 39 Montane Vole {Microtus montanus), 1 Meadow Vole (M pennsylvanicus), and 5 unidentifiable Microtus. Deer Mouse was the most abundant small mam- mal captured (1.84 captures/ 1 00 trap nights) and occurred throughout the sandhills in most habitats except in relatively dense low-stature sagebrush froughs (frap line 3) and mesic grass/sedge bottom (frap line 4). In these sites Montane Vole was the only small rodent captured. Typically, where one species was captured the other species was caught far less or not at all (Appendix 4); only one frap line (line 7) produced nearly equal numbers. However, voles were more likely to be caught in pitfalls (Appendix 5), and our collective data show that Montane Vole was also widely distributed in all habitats in the Sandhills. Meadow Vole, however, was captured only once, on pitfall line 5 in the East Hills. Least Chipmunk {Eutamias minimus) and Northern Pocket Gopher {Thomomys talpoides) were captured in both the East and West Hills. Most captures were from dune crests and dune slopes in erosion and deposition sites where evidence of thefr burrows was also most evident, consist L-tit with the observations of Lesica and Cooper (1999). Chipmunks were rarely captured (one of 1 9 individuals) on "flat" terrain (frap lines 4, 6, and 10: see Appendix 3). The same pattern was evident with the pocket gopher; 1 2 of 1 3 captured (all juveniles) were on dune slopes, and the one individual that wasn't was less than 20 m from a dune slope. Great Basin Pocket Mouse {Perognathus parvus) was captured 6 times, only in the East Hills (Appendices 5 and 6) and perhaps related to the late successional stage of the East Hills dunes. Pocket mice dig burrows at the base of sagebrush plants (Clark and Sfromberg 1985), which are larger and more mature (making burrows more stable) in the East Hills. Lower grazing intensities in the East Hills also make available more forb and grass seeds (Lesica and Cooper 1999), the primary foods of the Great Basin Pocket Mouse ( Verts and Kirkland 1988). Great Basin Pocket Mouse has been reported in Montana fewer than ten times, with the bulk of these records from 1961 (Hofl&nannetal. 1969b) and no reports since then unril our 1999 collec- tions. Our 1 999 collections also represent the first documented occurrence for the Centennial Valley, and a range extension about 60 km east from Sage Creek near Dell. Great Basin Pocket Mouse is a species of concern in Montana (Ap- pendix 2). We did not trap Wyoming Ground Squirrel {Spermophilus elegans) and observed few in the Sandhills, although we found some skulls at Coyote dens and in raptor pellets. Three were observed in the East Hills at a cattle guard along theroadinT13S,RlW,S28NEon 1 July,and2 were seen in the West Hills along the road in T13S,R2W,S22NE. Both sightings were near small stands of big sagebrush. This species was formerly considered a race of Richardson's Ground Squirrel {S. richardonii), and is found in 11 TABLE 3. Individual skulls recovered from raptor pellets collected throughout the Centennial Sandhills, Beaverhead County, in 1999. Species n % Microtus pennsylvanicus 56 47.1 Microtus montanus 33 27.7 Spermophilus species 11 9.2 Microtus species 5 4.2 Thorn omys talpoides 4 3.4 Peromyscus maniculatus 3 2.5 other mammal 4 3.4 bird 3 2.5 Montana in valley bottom and foothill sage plains and grasslands only in the southwestern part of the state (Hoflfinanetal. 1969b, Zegers 1984). Raptor pellets contained remains of 1 1 9 individu- als (Table 3) of which 112 represented 6 mammal "species". Birds and "other mammal" made up the remaining 7 individuals. Proportions of Micro- tus, Peromyscus, and Tiiomomys in pellet samples differed significantly from our trapping results (G = 77.6 l,df= 2, P<0.001). Almost half of the trap captures were Peromyscus, while this species represented only 3% of the pellet sample. Also striking was the ratio of Microtus montanus to M. pennsylvanicus in the two samples (G = 50.362, df= !,/'< 0.001). Nearly all of the 40 identified voles in our traps were M. montanus, but this species made up less than 40% of the pellet sample. Where the 2 microtine species co-occur, M pennsylvanicus prefers moist areas while M. montanus is found more often in drier sites (Hodgson 1 972); our trap results identify this as the pattern for the Centennial Sandhills, with M. pennsylvanicus present only infrequently near the perimeter of the sandhills proper Raptors (owls, harriers, buteos: Appendix 8) probably hunted most frequently over the extensive wetlands to the south of the sandhills, capturing M pennsylvanicus where it is likely more abundant. and returned to perches in the sandhills to digest their meals and cast pellets. This hypothesis is supported by the presence of three Muskrat (Ondatra zibethicus) skulls in the pellet sample. Peromyscus tends to avoid wet habitats (Clark and Stomberg 1985), explaining its low represen- tation in raptor pellet samples and providing additional support for the above hypothesis. Carnivores: We detected 3 carnivore species during our survey. Coyotes (Canis latrans) were often heard in both portions of the sandhills, and 2 dens were found (one each in the East and West hills). We noted little sign of Badger {Taxidea taxus), but found a skull in the West Hills. Red Fox (Vulpes vulpes) was seen once, on 2 July in the East Hills. Coyote and/or Red Fox probably raided some of our frap lines, as there was evi- dence that a carnivore had disturbed fraps on a few occasions. We failed to find any sign of Striped Skunk {Mephitis mephitis) in the sandhills, but anticipate that this species is some- times present, especially along the southern margins adjacent to wetlands. Ungulates: Our survey documented 3 ungulate species in the Sandhills. A small band of Prong- hom (Antilocapra americana) was observed daily in the West Hills (2 fawns on 28 July) and another small band was seen less frequently in the East Hills. We observed a single cow Elk 12 (Cervus elaphus) on 26 May in the big sagebrush flats west of Tepee Creek, apparently heading for the lush vegetation adjacent to the southern edge of the sandhills. A lone doe Mule Deer {Odocoileus hemionus) was seen in dense big sage in the East Hills on 1 July. Birds We observed 29 bird species in the sandhills (Appendix 8), of which 7 were recorded only as flyovers. Most resident species (those encoun- tered daily in the sandhills) were typical of shrub steppe-grassland habitat elsewhere in Montana (Feist 1968, Best 1972, Bock and Bock 1987), and included two Montana Partners In Flight (PIF) Priority II species, both sagebrush obligates: Sage Thrasher and Brewer's Sparrow (Paige and Ritterl999). Of particular note were daily observations of at least 3 singing Grasshopper Sparrows in the West HiUs (T13S,R2W,S22 and 23) fi-om late May to early July, in extensive patches of grass with little low-shrub cover. This species is listed on the refuge checklist as rare or accidental in the Centennial Valley, but our obser- vations indicate a small breeding population may be established in the Sandhills. Grasshopper Sparrow is a ranked as a Priority n grassland species by Montana PIF, experiencing range-wide declines. We observed Sage Thrasher only in stands of mature (ca. 100 cm tall or taller) big sage. Al- though we saw this species daily, it was present only in low densities and we found no nests. Much more abundant was Brewer's Sparrow, which we found widely associated with sagebrush. We found four nests of Brewer's Sparrow (on 28 May a nearly completed nest in a 72 cm tall big sage; on 29 June with 4 eggs in a 45 cm tall three- tip sage; on 30 June with 1 egg [later 3] in a 9 1 cm tall big sage; on 2 July with 3 eggs in a 42 cm tall three-tip sage). Two nests of Vesper Sparrow, found on 30 June, contained 4 eggs and 4 young, respectively. Both nests were built on the ground, one at the base of a 24 cm tall rabbitbrush (Chrysothamnus) and the other in a small bunch of grass. One Homed Lark nest was found on 25 May, containing 3 eggs; the cup was sunk in the ground next to a thick tuft of grass in an early-seral site with sparse grass and no shrub cover Other shrub-steppe grassland species fi^equently noted included Short-eared Owl, Savannah Sparrow, and Westem Meadowlark; we failed to find nests of any of these species. Pairs of Long- billed Curlew also appeared twice; one was very vocal near drift array 2 in the East Hills on 29 June and probably had a chick nearby. Ferruginous Hawks were seen on two occasions, and an old ground nest atop a high dune in the West Hills indicated this species sometimes nests in the sandhills. All five species are on the reftige list as confirmed breeders. Ferruginous Hawk and Long-billed Curlew are Montana PIF Level II Priority grassland species. Amphibians and Reptiles We documented 2 amphibian species. Tiger Salamander (Ambystoma tigrinum) and Striped Chorus Frog {Pseudacris triseriata), and one species of reptile, Westem Terrestrial Garter Snake (Thamnophis elegans), in the Centennial Sandhills in 1999 (Appendix 7). The Nahiral Heritage Program database had no previous records of these species for the sandhills (Roedel and Hendricks 1 998), but each has been docu- mented previously on refiige lands and elsewhere in the upper Centennial Valley It seems likely that the chorus fi"og and garter snake have been encountered previously in the sandhills but not reported. None of these species is of special concern in Montana, as all are widespread in the state. Tiger Salamanders were captured in pitfall traps in the East Hills. On 28 June, 2 adults were recov- ered fi-om pitfall line 5 and a single adult fi-om pitfall line 6 (see Figure 1 and Appendix 3 for locations). Another adult salamander was recov- ered from drift array 3 on 22 September These animals belong to the group called mole sala- manders, named for their use of burrows as adults. 13 Following breeding in nearby wetlands to the south. Tiger Salamanders probably return to the sandhills in search of underground refugja The population in the upper Centennial Valley may persist because of the Sandhills' proximity to extensive breeding habitat nearby in the wetlands. Striped Chorus Frog was heard calling in many wetland locations in and near the sandhills in May and June, especially along Tepee Creek and from the wetlands immediately south of the West Hills. Two dispersing adults were recovered from drift array 2 on 22 September; another two were recovered at drift array 3 on the same date. These individuals may have been seeking burrows (Koch and Peterson 1995), as they are often found far from permanent water elsewhere in Montana (personal observation) and sometimes breed in temporary ponds in road fracks. Most observations of Western Terrestrial Garter Snake, in June and July, were in sandy roads in both the East and West Hills. This species was also observed ofi-road in the West Hills (T13S,R2W,S23SW)on 1 July This widespread species is often associated with wetland and aquatic habitats in the Greater YeUowstone Eco- system (Koch and Peterson 1995). Insects Tiger Beetles: We documented 4 tiger beetle species in the Centennial Sandhills in 1 999: Cicindela decemnotata, C. formosa, C. longilabris, and C. tmnquebarica (Appendix 9). We had hoped to find the globally rare Idaho Dunes Tiger Beetle (C arenicold), but did not. The Centennial Mountains are a formidable barrier between the Centennial Sandhills and the nearest population of this Idaho endemic, in the St. Anthony Dunes of Fremont County (Rumpp 1967, Logan 1995). Nevertheless, fiirther searching would be worthwhile, and might also yield other species of tiger beetle new to the Centennial Sandhills fauna Transect counts (Table 4) and pitfall data show that Cicindela formosa was the most abundant tiger beetle in the West Hills, and C. decemnotata was the most abundant species in the East Hills. Both species were especially prevalent in sandy sites with sparse vegetation cover (early-seral vegetation in erosion and deposition sites). Our data support the observation of Lesica and Cooper (1999) that C. formosa is mostly con- fined to this kind of habitat. It was captured in pit fall traps on pitfall lines 1,2, and 3, and at drift array 1 , all in the West Hills. C. decemnotata was captured in on pitfall line 5 and at drift array 3, both in the East Hills. However, both species occurred outside their areas of concentration. We counted a few C. formosa on road fransects in the East Hills (Table 4) but never saw or captured them there off of the road. During a 25 May fraverse of the West Hills (T13S,R2W,S22 and S23) we noted 2 C. decemnotata among about 160 C. formosa in 14 blowouts and deposition sites. Cicindela tranquebarica, was seen almost exclusively on the road near Tepee Creek (Table 4), where the water table was probably near the ground surface and the sand sometimes slightly damp. This was the only tiger beetle known to occur with the Idaho Dunes Tiger Beetle at some sites (Rumpp 1967, Logan 1995) and tends to be a habitat generalist (Pearson et al. 1997, Leonard and Bell 1999). C longilabris was seen only in the East Hills (T13S,R1 W,S35SWSW), twice on 27 May in the presence of C decemnotata on a sandy game frail in mid-seral habitat. C longilabris is less associated with sandy habitats and more often found in forested or alpine sites (Pearson et al. 1 997, Leonard and Bell 1 999). We saw all tiger beetle species, with the exception of Cicindela longilabris, throughout the summer from late May to late September, though all were more abundant between late May and early July. All species, again with the exception oi Cicindela longilabris, were observed copulating between 27 May and 1 July. The presence of C. formosa in the Centennial Sandhills is noteworthy. This location is well 14 T3 C 03 (f) "to >r» I S o I ^ to *- 0) c .t; — w o CO ro TO "o -J= CD cc Q^ o O O) CD CO c o O T3 (U O CD Q. C CO E o o 0) -^ a3 ^ ^ i2 0 o B ^ 1 ^ O in O = . < < c CO ^ JS CD CD CO to n o O 3 E c ■o t E > vS ^ ^ __^ d d _c CO CM S" d r~- T- r~- z s CD O ■S -2 iS Oi ^ ^~. (A .0) *o CD -Q C CD -Q ■S is o o -S o c T^ T-^ 00^ CD CD CD 0) a 3 D- 3 C3- CD 0 0 to CO CO O O O (0 C C O O O P P P 5 ^ ^ ^ ^ 5 b d d d d 0 O (J ^■^ u. 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The list is nowhere near complete, and the collecting conducted was not sufficient to identify specific microhabitat associations in the sandhills, if in fact they occur. Most of the species collected associate primarily or exclusively with open grasslands or shrub-steppe habitats (Opler 1999); grasses, lupines, stonecrops, and asters are the larval food plants for several species. In the latest published state list (Kohler 1980) Beaverhead County is not listed as a location for four of the species (Satyriumfuliginosum, Icahcia lupini, Oarisma garita, and Hesperia juba). Considerable collecting has been under- taken throughout the state since then, and there now are coimty records for each (W. Kerling and S. Kohler personal communication). However, only limited collecting has been conducted in the Centennial Sandhills, and these may be new records for this specific locality. Discussion We found a variety of vertebrate and invertebrate species using the Centennial Sandhills during our 1 999 inventory. It is likely that a few additional vertebrate species will be discovered in the sandhills when more surveys are undertaken. The list of invertebrates is in its infancy; we expect sand obligate species (Rust 1 986) to be identified when additional invertebrate groups are studied. For now, the species of tiger beetles identified represent the only invertebrate group that is probably nearly complete. For all vertebrate and invertebrate species identified, several stand apart as having restricted distributions tied to physical featijres or vegetation within the Centennial Sandhills. Several mammal species in the Centennial Sandhills have specific habitat requirements, although their microhabitat relationships are not clear. Perhaps of greatest interest are the four manmial species of special concem that are now known to occur in tiie sandhills. Both Pygmy Rabbit and Black-tailed Jackrabbit are associated with moderate or dense stands of sagebrush (MacCracken and Hansen 1982, Katzner and Parker 1997), which provide food for the former species and shelter for both; Black-tailed Jackrab- bit is more abundant in ungrazed habitat where grass cover is greater Currently both species are present in very low number in the sandhills, and this probably is related to the limited availability of preferred sagebrush habitat. However, low jackrabbit density throughout the Centennial Valley is reflected in their low fi^equency of occurrence in raptor {Buteo) diets (Restani 1 99 1 ), and other factors may be limiting their abundance. In the sandhills. Great Basin Pocket Mouse appears to be restricted to stabilized low dunes, as they were captured only in the East Hills, despite intensive trapping in the West Hills. This partem might be explained by a greater availability of grass and forb seed (Lesica and Cooper 1999) and better burrow stability afforded by more mature sage- brush. Preble's Shrew, unlike the pocket mouse, appears to be more widespread at low density (assuming the unidentified shrews indicated in Table 2 were this species) and not tied to any particular succession stage or physionomic class, so long as sagebrush cover is present. For both species, additional systematic trapping to define distributions and microhabitat associations is desirable. Of the other small mammals. Least Chipmunk and Northern Pocket Gopher are found where tiiere is significant topographical relief in the sandhills, associated with dune slopes and crests regardless of the succession stage (early to late serai). However, pocket gopher activity is most evident in 16 early serai sites, as noted by Lesica and Cooper ( 1 999). Both species are virtually absent in sand flats or broad inter-dune troughs. Meadow Vole is restricted to the edges and small depressions of the sandhills where more mesic habitat is available or nearby. Masked Shrew, Dusky Shrew, Mon- tane Vole, and Deer Mouse are widespread, although the latter species apparently is uncommon in expansive sandflats and broad inter-dune troughs. Five bird species noted in the sandhills are state PIF Priority II species. For one of these. Ferrugi- nous Hawk, there is no evidence of current breeding, but the species was observed hunting in the area and an old ground nest was found in the West Hills. Presence of this hawk in the sandhills is probably determined by prey availability and landscape structure (nest sites), although habitat availability could affect its presence indirectly through influences on its favored prey (Bechard and Schmutz 1 995 ), which in the Centennial Valley are voles, ground squirrels, and pocket gophers (Restani 1991). Our observations on the other 4 PIF Priority species (Long-billed Curlew, Sage Thrasher, Brewer's Sparrow, Grasshopper Sparrow) indicate confirmed or likely breeding in the sandhiUs. Long-billed Curlews seek breeding sites with short dense grass usually < 25 cm in height (Allen 1 980, Pampush and Anthony 1993, Paige and Ritter 1999). This species is currently uncommon in the sandhills, but behavior of one pair indicated the presence of young. Sage Thrasher and Brewer's Sparrow are sagebrush obligates, closely associated with sagebiiish of different structure and negatively associated with grass cover (Paige and Ritter 1 999, Reynolds et al. 1999,Rotenberryetal. 1999). Populations of these species drop where sagebrush cover is below 1 0% over large areas. Sage Thrasher is most closely associated with tall dense sage, while Brewer's Sparrow occurs in sage < 1 .5 m tall and in less dense stands. Brewer's Sparrow is wide- spread and relatively abundant in the Centennial Sandhills wherever sagebrush is present; Sage Thrasher is restricted to small patches of taller big sage and dense stands of the same. Grasshopper Sparrow occurs in the Centennial Sandhills in a small and possibly isolated breeding population (at least 3 singing males) in relatively dense grass with low sagebrush cover, so far known only fi-om the West Hills. Grasshopper Sparrow settles in sites with taller grasses and generally avoids grasslands with extensive shrub cover, although some shrub cover is favored ( Vickery 1 996); in sagebrush- grassland in southcentral Montana, this species was significantly less abundant on plots that experienced fire eradicating all sagebrush cover (Bock and Bock 1987). We found no sign of Greater Sage-Grouse {Centrocerciis urophasianus) in the sandhills during our survey. Absence could be due in part to a lack of adequate density and height of sage- brush favored as summer habitat (J. Roscoe personal communication). Only three amphibian and reptile species were observed in the sandhills. None appear closely associated with any habitat other than the various adjacent wetlands. However, the population of tiger salamander that exists in the upper Centennial Valley may persist largely because of the close proximity of the sandhills to extensive wetlands, providing it ideal habitat in which to find refuge in burrows during non-breeding periods. Our survey of diumal butterflies was so brief that we could not identify pattems of landscape use. Nevertheless, we can predict areas where some species are likely to occur, based on their larval food plant preferences (Opler 1 999). Larvae of the 3 skipper species feed on grasses and sedges, so we would expect them to occur widely in the Sandhills. Riding's Saytr feeds on grasses, espe- cially blue grama [Bouteloua gracilis), and will probably be most prevalent in the East Hills where it was commonly seen in 1999. Both Boisduval's Blue and Sooty Hairstreak specialize on lupines {Lupinus spp.), so we expect these butterfly species to occur throughout the sandhills in all successional stages, but more commonly in 17 stabilized late-seral areas of the East Hills where lupines are most abundant (Lesica and Cooper 1999). Rocky Mountain Parnassian specializes on stonecrop (Sedum) and will likely be found where this plant is most abundant, probably the East Hills. For butterfly species requiring specific larval food plants, such as some of the above, additional survey work might reveal correlations between the predicted distributions and various successional stages of Sandhills vegetation. Tiger beetles provide the best examples of Sandhills animal species that are closely associated with early-seral vegetation and unstable sites, like the 4 rare plant species studied by Lesica and Cooper (1999). Indeed, tiger beetles were one of the &st animal groups in which different species were found to favor specific successional stages (Shelford 1907). In our surveys, two of the Centermial Sandhills species, Cicmdelaformosa and C. decemnotata, were most common in early-seral erosional or depositional sites with sandy soil and low vegetation cover These habitats closely match those described for C formosa at other locations (Shelford 1 907, Wallis 1961,Knisleyl979). C decemnotata, however, is not considered a sand dunes and blowouts specialist like C formosa, but is found throughout its range in upland grassland, arid shrubland, and clay banks habitats (Pearson et al. 1997). For example, the species is listed as an uncommon species of the Idaho National Engineering Laboratory northwest of Idaho Falls (Stafford et al. 1 986), where it is found on sandy loams and loess (Aridisols) in sagebrush-grasslands. In western Canada it has been collected on dry, gravelly clay soils (Wallis 1 96 1 , Hooper 1 969 ) . Its broader range of habitat associations might explain why C decemnotata was the prevalent tiger beetle in the East Hills, where the dunes are more stabilized with in- creased vegetative cover (Lesica and Cooper 1999). Overall, however, this species too was more strongly associated with low-cover sandy sites in the Sandhills. Competition may offer further explanation for the distribution patterns we found of these respective tiger beetle species in the Centennial Sandhills. Because the local distribution of tiger beetles is determined by preferred oviposition substrates (Shelford 1907), Cicmdelaformosa and C. decemnotata may be competing for similar egg- laying habitat in the SandhiUs. C. formosa, being the larger of the two species, may be dominant at breeding sites in the West Hills and exclude C decemnotata fi-om the more extensive early-seral habitat that is available there. Further study might clarify whether such competitive interaction accounts for their respective distribution patterns in the Sandhills. Recommendations and Conclusions Most habitats support plant and animal species that are generalists-those found across a wide array of habitats, and specialists-those with restricted distributions and specific habitat require- ments (Cody 1974). This complicates multi- species management because habitat manipula- tions for the benefit of one species will likely be at the expense of others. The challenge, then, is to design management strategies that are effective in maintaining and/or restoring the full range of plant and animal species native to an area. Perhaps the best management approach for the Centennial Sandhills fauna is to focus on disturbance pro- cesses under which these species evolved, and which maintain a diverse array of cover conditions and stages of plant succession (Lesica and Coo- per 1999) at specific spatial and temporal scales. In pursuing this approach, it should be kept in mind that the Sandhills themselves are but one site, albeit unique, in the larger Centennial Valley system. Adaptive management should include larger-scale disturbances, since small-scale disturbances alone probably do not replicate former patch dynamics across the entire Centen- nial Valley. 18 Lesica and Cooper ( 1 999) recommended a number of measures for returning natural distur- bance cycles to the Sandhills at appropriate time intervals (their recommendations do not address the question of spatial scale and patchiness of disturbance that are optimal for the Sandhills). We discuss these recommendations below, emphasiz- ing their implications for the Sandhills' animal species. Additional guidelines appropriate to the Centennial Sandhills are presented in Peterson (1995), Saab etal. (1995), and Paige and Ritter (1999). Sagebrush manipulation Sagebrush encroachment has contributed to the stabilization of the Sandhills. Sagebrush removal has complex impacts on the plants and animals associated with it (Peterson 1995), but there is good evidence of the immediate and short-term effects on several animal species. Extensive clearing of sagebrush (especially mature big sage) will have negative impacts on Pygmy Rabbit, Black-tailed Jackrabbit, Sage Thrasher, Brewer's Sparrow, and possibly Great Basin Pocket Mouse and Preble's Shrew (Best 1 972, Bock and Bock 1987, Verts and Kirkland 1988, Comely et al. 1992, Rauscher 1997, Paige and Ritter 1999, Reynolds et al. 1999). However, conversion of sagebrush to grassland benefits Lx)ng-billed Curlew, and Grasshopper Sparrow as long as scattered shrubs are left at low density (Bock and Bock 1987, Vickery 1996). Sagebrush manipulation, if conducted, should be limited and dispersed to maintain large expanses of sagebrush cover (over 10%) in various ages and size classes. Stands of dense mature sagebrush should probably be left undisturbed, as they are especially important sites for Pygmy Rabbit and Sage Thrasher (Rauscher 1 997, Paige and Ritter 1 999) and are uncommon in the Sandhills. Fire Fire is a natural process of the Sandhills land- scape. Fire suppression leads to a decline in diversity of successional habitats through vegeta- tion encroachment; in the eastern U. S . , loss of some tiger beetle species requiring open habitat has been linked to fire suppression (Knisley and Schultz 1997). The effects of fire will probably be similar to mechanical/chemical removal of sage- brush, producing a decrease in overall shrub cover for several years. However, because fire bums unevenly it creates a mosaic of successional habitats leaving some shrub cover if properly managed. Sage Thrasher and Brewer's Sparrow persist following prescribed fire, if the bum pattem leaves a patchwork of stmctural and cover condi- tions (Rotenberry etal. 1999). Absence of Greater Sage-Grouse in the Sandfiills and else- where in the Centennial Valley may relate to fire, in that spring-cool bums enhance the abundance of three-tip sage. Threetip sage tends to be avoided in summer by sage-grouse because it offers less cover of the appropriate height and density (J. Roscoe personal communication). Fire could benefit species like the Grasshopper Sparrow by stimulating increased growth in grasses, thereby providing more nesting cover Some increased availability of grasses is also beneficial to Black-tailed Jackrabbit and Great Basin Pocket Mouse, providing increased cover and food for each. Controlled fire may also be used to reactivate dune dynamics by removing bunchgrasses that stabilize the Sandhills (Lesica and Cooper 1999). However, as Lesica and Cooper ( 1 999) pointed out, effectiveness of fire in creating early and mid-seral conditions will vary depending on a large variety of conditions, includ- ing dune topography and current cover conditions. Invasion of exotic grasses (especially cheatgrass) could affect intensity and fi-equency of natural fires and damage native species habitat, through indefinite loss of sagebrush cover (Paige and Ritter 1 999). Close monitoring for invasion of exotic grasses should be a priority. Livestock grazing Livestock grazing can have many direct impacts on the Sandhills fauna (Saab et al 1995, Lesica and Cooper 1999); these include trampling, competition for food, and mechanical alteration or removal of cover. Cattle compete for food with 19 native herbivores such as Black-tailed Jackrabbit and Great Basin Pocket Mouse, which tend to be more abundant on ungrazed sites (MacCracken and Hansen 1982, Verts and Kirkland 1988). Moderate to heavy livestock grazing reduces habitat quality for Grasshopper Sparrow (Saab et al. 1 995, Vickery 1 999) by removing nesting cover On the other hand, this type of grazing may benefit Long-billed Curlew and more common species like Homed Lark by reducing vegetation height and cover if grazing occurs before the onset of nesting (Paige and Ritter 1 999). In the Sandhills area, nesting commences for many bird species before cattle are introduced (personal observation). Heavy grazing should benefit tiger beetle species associated with early-seral disturbance by creating more early and mid-seral habitat. Lesica and Cooper ( 1 999) suggested that heavy grazing will also help maintain early-seral vegetation on slopes where trampling in significant. However, livestock can destroy tiger beetle larvae by trampling their burrows (Knisley and Sdchultz 1 997), especially if livestock are concentrated in small areas or are grazed at high densities. As with fire, grazing is most beneficial and usefii as a management tool when it creates a mosaic of cover types and disturbance regimes. The most reasonable grazing system for the Sandhills is probably some form of rest or deferred rotation grazing (Saab et al. 1 995 ), where portions of the Sandhills are left undisturbed while others are grazed. These grazing systems distribute the disturbance across the landscape in an uneven pattern. Currently, early-seral habitat is most abundant in the West Hills where grazing and disturbance is also greatest. There is an obvious correlation here between grazing and the presence of early-seral vegetation in the Sandhills. Concluding remarks Lesica and Cooper ( 1 999) recommended that prescribed fire be used every 20-30 years to remove bunchgrasses and sagebrush in patches of some unspecified patch size. Controlled fire followed by intense livestock grazing for 1-2 years could significantly reduce vegetation cover, reinitiating blowout development in the East Hills and maintaining successional dynamics in the West Hills. Through use of natural and controlled fire and grazing, early-seral conditions to which the rarest species are linked should increase in the Sandhills. This approach appears most appropri- ate for sandhills invertebrates and small mammals, such as tiger beetles, shrews, and pocket mice, with specific small patch requirements. However, as Lesica and Cooper ( 1 999) prudently pointed out, their recommendations should first be tested by means of replicated demonstration areas spread through the Sandhills. Demonstration areas would be used to determine the relationships between scale, fi^equency, and intensity of distur- bances that will maintain the mosaic of early- to late-seral vegetation "capable of supporting the fioll spectrum of native species (Lesica and Cooper 1999, p. 300)." We concur with the suggestions of Lesica and Cooper ( 1 999), with an additional comment. The most effective management program will also involve coordinating the activities of all owners (Fish and Wildlife Service, Bureau of Land Man- agement, State, and Private) with lands in the Sandhills, as the entire site should be managed as an integrated unit with a unified goal. Extending this reasoning one additional step, the Sandhills should also be managed as but one unit, albeit unique, within the larger sagebrush-grassland system of the entire Centennial Valley. Future work It remains to be determined how unusual the Sandhills fauna is for the entire Centennial Valley, especially the distributions and associations of invertebrates, small mammals, and songbirds, as few concentrated surveys have been conducted elsewhere in the valley. We therefor recommend additional surveys for sagebrush obligate and grassland associated vertebrates (e.g.. Sage Thrasher, Brewer's Sparrow, Grasshopper Sparrow, Preble's Shrew, Great Basin Pocket Mouse, Pygmy Rabbit) and invertebrates (e.g.. 20 tiger beeties, grasshoppers, butterflies) throughout the entire Centennial Valley. This survey work would help place the significance of the Sandhills- associated fauna in the larger landscape context. In conjunction with habitat modeling, valley- wide surveys could further inform management regard- ing patch size requirements and distribution across the landscape. Because the Centennial Valley is an integrated system, management of special concern species should be conducted across the entire valley rather than at specific sites within the valley. Species such as early-succession sandhills obligate plants and invertebrates, restricted to unique sites and requiring special management attention, are the exceptions. Finally, we also recommend additional survey work be conducted in the Sandhills themselves for two reasons. First, Sandhills distribution and status for vertebrate species of special concern or high conservation interest including Preble's Shrew, Pygmy Rabbit, Black-tailed Jackrabbit, Great Basin Pocket Mouse, Sage Thrasher, and Grasshopper Sparrow are still uncertain, and microhabitat relationships remain largely unknown. To understand how these species will respond to prescribed disturbance in the Sandhills requires better information about their habitat requirements and distributions. Second, there are groups of invertebrates that were not tiioroughly surveyed but which are known to contain sandhills-obligate species (spiders, ground beetles, grasshoppers) closely tied to early stages of succession (Rust 1986), or species with specific food plant require- ments (butterflies) that serve as indicators of the spectrum of sandhills habitats. These groups probably are the best animal indicators of the overall health of the Centennial Sandhills because their requirements are quite specific. 21 Literature Cited Alden,W. C. 1953. Physiography and glacial geology of western Montana and adjacent areas. U. S. Geological Survey Profes- sional Paper 23 1 . 200p. Allen, J.N. 1980. The ecology and behavior of the Long-billed Curlew in southeastern Washington. Wildlife Monographs No. 73:1-67. Allen, K. L., D. Flath, and T. Weaver. 1997. Small mammal capture efficiencies among three trap types. Intermountain Journal of Sciences 3: 1-6. Best,L. B. 1972. 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Smithsonian Institijtion Press, Washington, D.C. 409 p. Jones, J. K., Jr., D. C. Carter, H. H. Genoways, R. S. Hoffinann, D. W. Rice, and C. Jones. 1986. Revised checklist of North American mammals north ofMexico, 1986. Occasional Papers of The Museum Texas Tech University Number 107:1-22. Katzner, T E., and K. L. Parker. 1997. Vegeta- tive characteristics and size of home ranges used by Pygmy Rabbits {Brachylagus idahoensis) during winter. Journal of Mammalogy 78: 1063-1072. Kirkland, G. L., Jr., R. R. Parmenter, and R. E. Skoog. 1997. A five-species assemblage of shrews from the sagebrush-steppe of Wyoming. Journal ofMammalogy 78:83- 89. Knight, D.H. 1994. Mountains and plains: the ecology ofWyoming landscapes. Yale University Press, New Haven, CT. 338 P- Knisley, C. B. 1979. Distiibution, abundance, and seasonality of tiger beeties (Cicindelidae) in the Indiana Dunes region. Proceedings of the Indiana Academy of Science 88:209-2 17. Knisley,C.B.,andT.D. Schultz. 1997. The biology of tiger beetles and a guide to the species of the South Atlantic States. Virginia Museum ofNatural History Special Publication Number 5. 2 1 0 p. 23 Koch, E. D., and C. R. Peterson. 1995. Am- phibians & reptiles of Yellowstone and Grand Teton national parks. University of Utah Press, Salt Lake City, UT. 1 88 p. Kohler,S. 1980. Checklist of Montana butter- flies (Rhopalocera). Journal of the Lepi- dopterists' Society 34: 1-19. Leonard, J. G, and R. T. Bell. 1999. Northeast- em tiger beetles: a field guide to tiger beetles of New England and eastern Canada. CRC Press, Boca Raton, FL. 176 p. Lesica, P, and S. V. Cooper. 1997. Presettlement vegetation of southern Beaverhead County, Montana. Montana Natural Heritage Program, Helena, MT. 35 p. Lesica, P., and S. V. Cooper. 1999. Succession and disturbance in sandhills vegetation: constructing models for managing biologi- cal diversity. Conservation Biology 13:293-302. Lesica, P., G Moore, K. M. Peterson, and J. H. Rumley 1984. 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Ogdon, UT: US Department of Agricul- ture, Forest Service, Intermountain Research Station. 88 p. North, G J., and R. E. Marsh. 1999. Black- tailed Jackrabbit, Lepus califomicus. Pp, 699-701 , In The Smithsonian Book of North American Mammals (D. E. Wilson and S. Ruff, eds.). Smithsonian Institution Press, Washington, DC. Opler, P A. 1999. A field guide to Western Butterflies, second edition. Houghton MifiQin Company, New York, NY. 540 p. Paige,C.,andS.A. Ritter. 1999. Birds in a sagebrush sea: managing sagebrush habitats for bird communities. Partners in Flight Western Working Group, Boise, ID. 47 p. Pampush, G J., and R. G Anthony 1993. Nest success, habitat utilization and nest-site selection of Long-billed Curlews in the Columbia Basin, Oregon. Condor 95:957-967. Pearson, D. L., T. G Barraclough, and A. P. Vogler 1997. Distributional maps for North American species of tiger beetles (Coleoptera: Cicindelidae). Cicindela 29:33-84. 24 Peterson, J. G 1995. Ecological implications of sagebrush manipulation: a literature review. Montana Fish, Wildlife & Parks, Helena, MT. 49 p. Ports, M. A., and S. B. George. 1990. Sorex preblei in the northern Great Basin. Great Basin Naturalist 50:93-95. Povilitis,T.,andM. H. Mahr. 1998. Montana's Centennial Valley: natural diversity hot spot and wildland corridor Natural Areas Journal 18:116-123. Rauscher, R. L. 1997. Status and distribution of the Pygmy Rabbit in Montana. Montana Fish, Wildlife & Parks Nongame Program, Bozeman,MT. 19 p. + appendices. Restani,M. 1991. Resource partitioning among three Buteo species in the Centennial Valley, Montana. Condor 93 : 1 007- 1 0 1 0. Reynolds, T. D., T. D. Rich, and D. A. Stephens. 1 999. Sage Thrasher {Oreoscoptes montanus). In The Birds of North America, No. 463 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA. 24 p. Roedel, M. D., and P Hendricks. 1998. Am- phibian and reptile inventory on the Headwaters and Dillon Resource Areas in conjunction with Red Rock Lakes Na- tional Wildlife Refuge: 1 996- 1 998. Mon- tana Natural Heritage Program. Helena, MT 68 p. Rotenberry, J. T, M. A. Patten, and K. L. Preston. 1999. Brewer's Sparrow (Spizella breweri). In The Birds of North America, No. 390 (A. Poole and F. Gill, eds. ). The Birds of North America, Inc., Philadelphia, PA. 24 p. Rumpp,N. L. 1967. A new species of Oc/We/a from Idaho (Coleoptera: Cicindelidae). Proceedings of the California Academy of Sciences 35:129-140. Rust,R. W. 1986. Seasonal distribution, trophic structure and origin of sand obligate insect communities in the Great Basin. Pan- Pacific Entomologist 62:44-52. Saab, V. A., C. E. Bock, T D. Rich, and D. S. Dobkin. 1995. Livestock grazing effects in western North America. Pp. 3 1 1-353, In Ecology and management of Neotropi- cal migratory birds: a synthesis and review of critical issues (T E. Martin and D. M. Finch, eds.). Oxford University Press, New York, NY. Shelford, V. E. 1907. Preliminary note on the distribution of the tiger beetles (Cicindela) and its relation to plant succession. Bio- logical Bulletin 14:9-14. Shook, G A. 1984. Checklist of tiger beetles from Idaho (Coleoptera: Cicindelidae). Great Basin Naturalist 44: 1 59- 1 60. Sokal, R. R. , and F. J. Rohlf 1981. Biometry, second edition. W H. Freeman and Company, San Francisco, CA. 859 p. Stafford, M. P, W F. Barr, and J. B. Johnson. 1 986. Coleoptera of the Idaho National Engineering laboratory: and annotated checklist. Great Basin naturalist 46:287- 293. Stebbins, R. C. 1985. A field guide to western reptiles and amphibians, second edition revised. Houghton MiflQin Company , Boston, MA. 336 p. Sutter, J., J. C. Munger, and D. A. Hengel. 1999. Sorex monticolus in shrub steppe habitat in the northern Great Basin. Great Basin Naturalist 59:102-104. 25 Tomasi, T. E., and R. S. Hoffinann. 1984. Sorex preblei in Utah and Wyoming. Journal of Mammalogy 65:708. Verts, B. J., G L. Kirkland, Jr.. 1988. Perognathus parvus. Mammalian Spe- cies No. 318:1-8. Vickery,P. D. 1996. Grasshopper Sparrow {Ammodramus savannarum). /m The Birds of North America, No. 239 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA, and The American Ornithologists' Union, Washington, D.C. 24 p. Wallis, J. B. 1 96 1 . The Cicindelidae of Canada. University ofToronto Press, Toronto, Ontario. 74 p. Willis, H. L. 1 968. Artificial key to the species of Cicindela of North America north of Mexico (Coleoptera: Cicindelidae). Journal of the Kansas Entomological Society 4 1:303-3 17. Wrigley, R. E. 1974. Mammals of the sandhills of southwestern Manitoba. Canadian Field- Naturalist 88:21-39. Zegers, D.A. 1984. Spermophilus elegans. Mammalian Species No. 214:1-7. 26 APPENDIX 1. Global and State Rank Guidelines For state ranks, substitute S for G in these defini- tions G 1 = Critically imperiled globally because of extreme rarity (typically five or fewer occurrences or very few remaining acres) or because of some factor(s) making it extremely vulnerable to exptirpation. G2 = Imperiled globally because of extreme rarity (typically six to 20 occurrences or few remaining acres) or because of some factor(s) making it very vulnerable to extirpation. G3 = Vulnerable; either very rare and local throughout its range or found locally (even abundantly at some of its locations) in a restricted range (e.g. a single Great Plains state, a single physiographic or ecoregional unit) or because of other factors making it vulnerable to extirpation throughout it's range. G4 = Apparently Secure; Uncommon, but not rare (although it may be quite rare in parts of its range, especially at the periphery). Apparently not vulnerable in most of its range. G5 = Secure; Common, widespread, and abundant (though it may be quite rare in parts of its range, especially at the periph- ery). Not vulnerable in most of its range. GU = Unrankable; Status cannot be determined at this time. G? = Unranked; Status has not yet been as- sessed. **Modifiers and Rank Ranges** ? A question mark added to a rank ex- presses an uncertainty about the rank in the range of 1 either way on the 1 -5 scale. G#G# Greater uncertainty about a rank is ex- pressed by indicating the fioll range of ranks which may be appropriate. Q A "Q" added to a rank denotes question- able taxonomy. It modifies the degree of imperilment and is only used in cases where the type would have a less imper- iled rank if it were not recognized as a valid name (i.e. if it were combined with a more common type). CRITERIA USED FOR RANKING The criteria for ranking are based on a set of quantitative and qualitative factors. These factors are listed below in order of their general impor- tance: a. Number of Element Occurrences (EOs); the estimated number of EOs throughout the Element's global range; b. Abundance: the estimated global abundance of the Element (measured by number of individuals, or area, or stream length covered); c. Size of Range: the estimated size of the Element's global range; 27 d. Distribution trend: the trend in the Element's distribu tion over it's global range; e. Number of protected EOs: the estimated number of ad- equately protected EOs through- out the Element's global range; f Degree of threat: the degree to which the Element is threatened globally; g. Fragility: the fragility or susceptibility of the Element to intrusion; h. Other global considerations: for example, the quality or condi- tion of EOs that affect or may aflFect endangerment status; unexplained population fluctua- tions; reproductive strategies that are dependent on specific habitat; etc. 28 APPENDIX 2. Small mammal species of special concern from the Centennial Sandhills. 29 Sorexpreblei (Jackson,1922) Preble's Shrew Insectivora: Soricidae Global Rank: G4; State Rank: S3 DESCRIPTION: Preble's Shrew resembles other long-tailed shrews in Montana, although it is quite small (2.1-4.1 grams). The tail is bi-colored: dark above and pale below. Dorsal fur is grayish to brownish, with silvery pelage on the belly. Sexes are similar in appearance. This species is virtually impossible to identify using extemal criteria, however. One must examine the teeth and skull to properly distinguish this shrew from other species. There are medial tines on the first upper incisors well within the pigmented portion of the teeth, and the third unicuspid is larger than, or about equal in size to, the fourth unicuspid, placing this shrew in the cinereus group. A series of skull measurements is necessary to differentiate S. preblei from S. cinereus and S. haydeni where the species overlap. Condylobasal length is usually < 1 4.8 mm, cranial breadth is usually < 7.5 mm. DISTRIBUTION: Preble's Shrew ranges from northeastern California, northern Nevada, northern Utah, and southwestem Wyoming through eastern Oregon, southeastem Washington, central Idaho and across Montana, appearing as several disjunct populations, partly a resuh of unequal sampling across the geo- graphical range. In Montana Preble's Shrew has previously been confirmed in Big Hom, Dawson, Fergus, Gallatin, Glacier, Judith Basin, Ravalli, Silver Bow, and Sweet Grass counties (14 total locations), and reported from Carbon, Phillips, Valley, and Wheatland counties. The 1 999 records (this study) are the first for the Centennial Valley and Beaverhead County. 30 HABITAT: Recorded habitats of Preble's Shrew include arid and semi-arid shrub-grass associations, openings in montane coniferous forests dominated by sagebrush (Washington), willow-fringed creeks, marshes (Oregon), bunchgrass associations, sagebrush-aspen associations (California), sagebrush-grass associations (Nevada), and alkaline shrubland (Utah). In Montana, most sites where this species has been recorded are arid or semi-arid foothill sagebrush {Artemisia)-grass\and associations; a few collection localities have been from similar vegetation associations within montane coniferous forest clearings. COMMENTS: Status and habitat afiinities of Preble's Shrew need further attention and review. This species is difficult to distinguish from sympatric Masked (S. cinereus) and Hayden's (5. haydeni) shrews, and generally requires extensive pitfall frapping over many days to detect. At most localities where this species has been captured it is apparently rare. REFERENCE: Comely, J. E., L.N. Carraway, and B.J. Verts. 1992. Sorex preblei. Mammalian Species No. 416:1-3. HoSmann, R. S., P. L. Wright, and F. E. Newby 1969. The distribution of some mammals in Montana. I. Mammals other than bats. Journal of Mammalogy 50:579-604. 31 Brachylagus idahoensis (Merriam, 1891) Pygmy Rabbit Lagomorpha: Leporidae Global Rank: G4; State Rank: S2S3 DESCRIPTION: The Pygmy Rabbit is smaller than any other North American leporid (averaging about 400-450 grams), with very short hind legs and short rounded ears. The tail is small and inconspicuous with a buff-colored underside, rather than white as in cottontails (Sylvilagus). The upper parts are gray, with cinnamon buff on the nape and anterior surfaces of the legs. The skull is small, with a relatively large brain- case and auditory bullae. Supraorbital processes are long compared with those of members in the genus Sylvilagus. Postorbital extensions of the supraorbitals are broadest distally, instead of tapering to a blunt end as in Sylvilagus. Molariform teeth are relatively small. The anterior surface of the first upper molari- form tooth possesses but a single re-entrant angle while those of Sylvilagus have two or three re-entrant angles. The two pair of unpigmented incisors distinguish lagomorph skulls from all rodents. DISTRIBUTION: The geographic range of the Pygmy Rabbit includes most of the Great Basin in eastern California and Oregon, northern Nevada, western Utah, southern Idaho, isolated populations in southeast- em Washington and southwestern Wyoming, and extends into southwestern Montana. In Montana the Pygmy Rabbit occurs throughout Beaverhead (many locations), extreme southern Deer Lodge ( 1 location), and extreme southwestern Madison (2 locations) counties, with a questionable 1 937 record from Ravalli County. There are only three records from the Centennial Valley, one of which (in 1 997) was from the sandhills area 32 HABITAT: The Pygmy Rabbit is closely associated with aggregations of sagebrush (Artemisia) throughout their range, especially preferring tall dense clumps of big sage {A. thdentata) growing in loose soils; sage- brush is the major component of the diet. In Idaho it also occupies areas supporting greasewood {Sarcobatus). In southwestern Wyoming, the pygmy rabbit selectively uses dense and structurally diverse stands of sagebrush that accumulate a relatively large amount of snow; the subnivean environment provides access to a relatively constant supply of food while providing protection from predators and extreme cold weather. The Pygmy Rabbit makes extensive use of burrows largely of their own construction, with en- trances usually located at the base of sagebrush plants; burrows may have three or more entrances. COMMENTS : The Pygmy Rabbit may be locally abundant but unevenly distributed. It may have moved into Montana as sagebrush habitat increased in Beaverhead County following fire suppression during the late nineteenth century. The known distribution in Montana apparently has not changed much during the last 1 00 years. REFERENCES: Green, J. S., and J. T. Flinders. 1980. Brachylagus idahoensis. Mammalian Species No. 125:1-4. Rauscher, R. L. 1997. Status and distribution of the Pygmy Rabbit in Montana Montana Fish, Wildlife & Parks Nongame Program, Bozeman, MT. 1 9 pp. + appendices. 33 Lepus californicus (Gray, 1837) Black-tailed Jackxabbit Lagomorpha: Leporidae Global Rank: G5; State Rank: S2S3 DESCRIPTION: The Black-tailed Jackrabbit is a large (1 ,300-3,300 grams), slender hare with long legs and ears. The tail has a black dorsal surface that may continue as a line onto the lower back, distinguishing it from the larger White-tailed Jackrabbit (L. townsendii) which has a white tail. The upper parts may range from brown to dark gray; the belly and underside of tail are usually a pale gray. The ears are edged and sometimes tipped with black. Unlike the Snowshoe Hare and White-tailed Jackrabbit, Black-tailed Jackrabbits molt only once annually and do not take on a white winter coat. The interparietal bone is ftised with the parietals, distinguishing the skulls of hares from the cottontails (Sylvilagus) and Pygmy Rabbit (Brachylagus idahoensis). Presence of an anterior projection of the supraorbital process differentiates the skull of the two jackrabbit species from the congeneric Snowshoe Hare (L. americanus). The first upper incisors have a bi- or triflircate groove resulting in a complex fold on the anterior surface; L townsendii has a simple groove on the anterior surface of the first upper incisors. DISTRIBUTION: The Black-tailed Jackrabbit is widespread in the western and central United States, from westem Missouri and Arkansas west to the Pacific Coast, and from Washington and Idaho south to Hidalgo and Queretaro in central Mexico. In Montana the Black-tailed Jackrabbit has been documented only in Beaverhead ( 1 1 locations) and extreme westem Madison (2 locations) counties, with only two reports from the Centennial Valley (one from 1999 during this study). 34 HABITAT: The Black-tailed Jackrabbit inhabits open plains, fields and deserts, and open country with scattered thickets or patches of shrubs; ideal habitat includes short grasses and herbs for food and ease of locomotion, with scattered brush for cover This species often becomes abundant on overgrazed land because grazing encourages this type of vegetation, hi the Great Basin, the Black-tailed Jackrabbit often inhabits sagebrush (Artemisia) desert and semi-desert. COMMENTS: Black-tailed Jackrabbits may have entered Montana after 1900, following a widespread increase in sagebrush following fire suppression in Beaverhead County. This species is probably more abundant than the relatively few records indicate, although populations undergo dramatic fluctuations; the earliest record was published in 1937. REFERENCES: Hofimann, R. S., R L. Wright, and F. E. Newby 1969. The distribution of some mammals in Montana. I. Mammals other than bats. Journal of Mammalogy 50:579-604. North, G. J., and R. E. Marsh. 1999. Black-tailed jackrabbit, Lepus califomicus. Pp. 699-701 In The Smithsonian Book ofNorth American Mammals (D. E. Wilson and S. Rufl", eds.). Smithsonian Institution Press, Washington, D.C. 35 Perognathus parvus (Peale, 1848) Great Basin Pocket Mouse Rodentia: Heteromyidae Global Rank: G5; State Rank: S2S4 DESCRIPTION: Pocket mice are distinguished by their soft pelage, absence of spines or bristles, some- what hairy soles on the hind feet, greatly developed mastoids that extend beyond the occipital plane, audi- tory bullae meeting or nearly so anteriorly, and breadth of the interparietal less than the breadth of the interorbital. The skull has a perforated nasal septum. Grooved upper incisors and external fur-lined cheek pouches are shared by other members of the genus. Diagnostic characteristics of the Great Basin Pocket Mouse include a lobed antitragus, length of the hind foot > 20 mm, occipitonasal length > 24 mm, ears not clothed with white hairs, tail dark above and neither crested nor conspicuously tufted, and the presence of an olivaceous lateral line on the body. The Great Basin Pocket Mouse is the largest member of the genus ( 1 6.5-3 1 .0 grams); tail length is 1 1 0-1 20% of the length of the head and body. DISTRIBUTION: Great Basin Pocket Mice occupy almost the entire Great Basin Region of North America, fi-om south-central British Columbia southward through central and eastern Washington and Oregon, southern Idaho, southwestem Wyoming, most of Nevada and Utah, to northem Arizona and northeast and east-central California. In Montana, Great Basin Pocket Mice are documented only fi-om Beaverhead (8 locations) and Jefferson counties (1 location); the 1 999 records (this study) are the first fi-om the Centennial Valley. 36 HABITAT: The Great Basin Pocket Mouse inhabits arid and semi-arid sandy shrub-steppe covered with short grasses, sagebrush (especially ^A-Zeww/a tridentata), bitterbrush {Purshia tridentata), and rabbit brush {Chrysothamnus), and also is found in pinyon-juniper woodlands. Usually this species is found in habitats with light-textured loose and deep soils where it can burrow, but it also is sometimes present among rocks. The diet includes a variety of grass and forb seeds; this species may be diminished in areas with heavy livestock grazing because of reduced food availability. Loss of sagebrush cover also diminishes abundance. COMMENTS : The 1 999 records from the Centennial Sandhills are the first in Montana since 1 96 1 . The status of the Great Basin Pocket Mouse needs further attention and review. Intensive trapping using pitfall arrays could reveal many additional populations and define in finer detail the distribution, status, and habitat associations of the species in the state. REFERENCES: Hoffmann, R. S., P. L. Wright and F. E. Newby. 1969. Distribution of some mammals inMontana. I. Mairmials other than bats. Journal of Mammalogy 50:579-604. Verts, B. J. and G. L. Kirkland, Jr. 1 988. Perognathus parvus. 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West Hills is that portion west of Tepee Creek, East Hills is that portion east of Tepee Creek. TIGER BEETLES Species Habitat West Hills East Hills Cicindela decemnotata blowout, sandy road X X Cicindela formosa blowout, sandy road X X Cicindela longilabris grassy stabilized dune X Cicindela tranquebarica moist sandy/pebbly road X BUTTERFLIES Common Name Scientific Name West Hills East Hills Rocky Mountain Parnassian Parnassius smintheus X X Blue Copper Lycaena heteronea X X Dorcas Copper Lycaena dorcas X Sooty Hal rstreak Satyrium fuliginosum X X Melissa Blue Lycaeides melissa X X Boisduval's Blue Icaricia icariodes X Lupine Blue Icaricia lupini X Zerene Fritillary Speyeria zerene X X Northern Crescent Phyciodes cocyta X Small Wood-Nymph Cercyonis oetus X X Riding's Satyr Neominois ridingsii X X Garita Skipperling Oarisma garita X Juba Skipper Hesperia juba X Common Branded Skipper Hesperia comma X X 44