status and Conservation Management of Terrestrial Mollusks of Special Concern in Montana Prepared for: The U.S. Forest Service By: Paul Hendricks Montana Natural Heritage Program Natural Resource Information System Montana State Library June 2003 MONTANA Natural Heritage Ftogtam status and Conservation Management of Terrestrial Mollusks of Special Concern in Montana Prepared for: The U.S. Forest Service Contract Number: Ol-lA-11015600-64 By: Paul Hendricks MONTANA Natuial Heritage Ptt^jtam ^it ^-^ MUSTAFA j^S^ijk yf>WTAHA ^T^itate If jIV Natural Kesouice ^ Library *^jj^ Iniomiation System © 2003 Montana Natural Heritage Program P.O. Box 20 1800 • 1515 East Sixth Avenue • Helena, MT 59620-1800 • 406-444-5354 The preferred citation for this document is: Hendricks, P. 2003. Status and Conservation Management of Terrestrial MoUusks of Special Concern inMontana. Report to Region I, U.S. Forest Service. Montana Natural Heritage Program, Helena. 67 pp. + appendicies. EXECUTIVE SUMMARY This document presents information on the distribution and status of 1 5 terrestrial moUusk taxa (species and subspecies) of conservation concern in Montana that have been found on or near lands administered by the Northern Region (Region 1 ), U. S . Forest Service. Included in this group are ten snail taxa and five slug taxa. Each species or subspecies is on the current joint Montana Natural Heritage Program and Montana Fish, Wildlife and Parks Animal Species of Concern list (Carlson 2003), as either a Species of Concern (eight snail and three slug taxa) or On Review (two snail and one slug taxa); one slug species On Review (Udosarx lyrata) includes a subspecies {U. I russelli) that is a Species of Concern. Montana is the type locality (where the species or subspecies was first discovered and upon which the formal description is based) for ten of the moUusk taxa discussed in this report. A review of available literature and unpublished reports, museum records, personal discussions and correspondence, and field survey results provided only 66 locality records for all species and subspecies combined. No species has been reported in Montana at as many as 1 5 localities, and only two snails have been documented at as many as ten localities. Two snails remain known from single localities each (the type localities), and five other snails and slugs from two to four localities each. To date (2002), terrestrial moUusks of conservation concern have been found on or near seven National Forests in Montana: Beaverhead- Deerlodge, Bitterroot, Flathead, Gallatin, Kootenai, Lewis and Clark, and Lolo. Of the 66 total localities. Heritage Program zoologists discovered nine since 1 997, and two additional localities were first reported in 200 1 by other biologists. These results, obtained largely with a minimum of survey effort, indicate that new populations for several of the species of conservation concern are possible, even likely. However, given the history of collecting in the state west of the Continental Divide, it is expected that most of the moUusk taxa on the Heritage list will remain there, although their global and state ranks may ultimately be downgraded. In this report, species accounts for each taxon are provided that include details of taxonomy and species identification, life history and ecology notes, a distribution map, and comments on status, potential threats, and land ownership at documented (historical and recent) locations. Appendices include a summary of all location and museum collection information, guidelines for conducting surveys and inventories of terrestrial moUusks, and a key to the genera of terrestrial moUusks in Montana. It is hoped that this document will 1 ) bring to the attention of Forest Service biologists the existence of a group of small animals of conservation concern that inhabit or may inhabit lands under their stewardship, and 2) help Forest Service biologists design and conduct forest inventories for these species. The ultimate goal of this document is to assure the long-term conservation of these species by having their needs addressed in forest plans. TABLE OF CONTENTS Acknowledgments iv Introduction 1 Species Accounts Snails Discus brunsoni 9 Discus shimeki 13 Oreohelix alpina 17 Oreohelix amariradix 21 Oreohelix carinifera 25 Oreohelix elrodi 29 Oreohelix strigosa berryi 33 Oreohelix yavapai mariae 37 Slugs Hemphillia danielsi 41 Magnipelta mycophaga 45 Zacoleus idahoensis 49 Species on Review Snails Polygyrellapolygyrella 53 Radiodiscus abietum 57 Slugs Udosarx lyrata 61 Bibliography 64 Appendix A. Global/State Rank Definitions Appendix B. Locality and Collection Records for 1 5 Terrestrial MoUusk Taxa of Conservation Concern in Montana Appendix C. Guidelines for Designing and Conducting Surveys of Terrestrial MoUusks Appendix D. Key to the Genera of Terrestrial MoUusks of Montana ACKNOWLEDGMENTS I am particularly grateful to Fred Samson (USDA Forest Service) for recognizing invertebrates as part of the native fauna inhabiting The Northern Region, and concluding there is a need to address the conservation issues invertebrates confront. John Carlson, Montana Natural Heritage Program (MTNHP) Lead Zoologist, was instrumental in seeing solidified the agreement between the U.S. Forest Service and MTNHP to develop this document. Information gathered here was assembled from published literature, unpublished reports, field surveys, museum collections, and personal communications with agency, academic, and private-sector biologists. I am grateful to the moUusk collection managers of the California Academy of Sciences (CAS), the Academy of Natural Sciences of Philadelphia (ANSP), the Field Museum of Natural History of Chi- cago (FMNH), and the U.S. National Museum (USNM) for providing museum records. I also extend thanks to Lee Fairbanks, Terry Frest, Bill Hammer, Bill Leonard, Tom Burke, Heike Reise, and Bryce Maxell for providing specimen records, advice, or both. Bill Leonard was also generous in sharing his photographs of several slug species. For help in the production of this report, I thank Anne Dalton and Terrie Kenney for scanning photo- graphs, Martin Miller for entry of location data into the MTNHP databases, Whitney Weber for map production and Cobum Currier for report formatting and production, and John Carlson for feedback, advice, and comments on earlier drafts of the report. All are, or were, fellow employees of the MTNHP Finally, I express my thanks to Dr. Royal Bruce Brunson (deceased). Emeritus Professor of the Depart- ment of Zoology, University of Montana and mid-twentieth century student of Montana's moUusk fauna, for sharing his knowledge and providing enthusiastic support of my novice attempts to rediscover what was known decades before. This report is dedicated to him. N INTRODUCTION Background. This document is intended to serve as a concise summary of current knowledge on the status, distribution, Ufe history, and ecology of terrestrial mollusks (slugs and snails) determined by the Montana Natural Heritage Program to merit state Species of Concern or On Review designation (see Carlson 2003). The information gathered has been used to 1) identify real and potential threats to terrestrial mollusks of conservation concern that may occur on U.S. Forest Service, Northern Region lands in Montana, and 2) develop guidelines for field surveys and monitoring schemes on Forest Service units for terrestrial mollusks of conservation concern. The project is a joint venture of the U.S. Forest Service, Northern Region with the Montana Natural Heritage Program. Species and subspecies in this document (Table 1) are included on the joint Montana Natural Heritage Program/Montana Department of Fish, Wildlife & Parks list of Animal Species of Concern (Carlson 2003). They were so listed based on information and recommendations in Frest and Johannes (1993, 1995) for species occurring in the Interior Columbia River Basin and the Black Hills of South Dakota and Wyoming (the Black Hills region includes two species of concern that also are present in Montana); several species included are covered in the Columbia River Basin invertebrate assessment report (Niwa et al. 2001), where listing is also recommended. Montana is the type locality (where the species or subspecies was first discovered and upon which the formal description is based) for 10 of these taxa (see Appendix B). Table 1. Terrestrial snail and slug Species Of Concern or On Review in Montana (Carlson 2003). An asterisk (*) following a scientific name indicates the species was recommended for listing in the Columbia River Basin invertebrate assessment report (Niwa et al. 2001). Scientific Name Common Name Heritage Rank^ Heritage Category Snails Discus brums oni"^ Mission Range Disc GlSl Concern Discus shimeki Striate Disc G4S1 Concern Oreohelix alpina'' Alpine Mountainshell GlSl Concern Oreohelix amariradix^ Bitterroot Mountainshell G1G2S1S2 Concern Oreohelix carinifera^ Keeled Mountainshell GlSl Concern Oreohelix elrodi^ Carinate Mountainshell GlSl Concern Oreohelix strigosa berryi Berry's Mountainshell G5T2S1S2 Concern Oreohelix yavapai mariae Gallatin Mountainshell G4?T1 SI Concern Polygyrella polygyrella Humped Coin GUSU Review Radiodiscus abietum Fir Pinwheel GUSU Review Slugs Hemphillia danielsi"^ Marbled Jumping Slug G1G3 S1S3 Concern Magnipelta mycophaga"^ Spotted Slug G2G3 SI S3 Concern Udosarx lyrata^^ Lyre Mantleslug GUSU Review/Concern Zacoleus idahoensis Sheathed Slug G3G4 S2S3 Concern ^ G = Global Rank, S = State Rank. See Appendix A for definitions of abbreviations and ranks. ^ A described subspecies, Udosarx lyrata russelli (Russell Mantleslug), is ranked G?T1 SI and placed on the Concern list. It is discussed under the Lyre Mantleslug because separate treatment is not justified here. Both forms of Udosarx lyrata were recommended for listing in the Columbia River Basin invertebrate assessment report (Nixa etal.2001). Although the two reports by Frest and Johannes form the basis for focus of mollusk conservation in Montana, it is worth noting that large portions of Montana still await evaluation of their molluscan fauna. The Interior Columbia River Basin report (Frest and Johannes 1995) covers just that part of Montana west of the Continental Divide and two peripheral species of concern; the Black Hills report (Frest and Johannes 1993) does not cover Montana at all, but discusses two species of concern present also in Montana. A Brief History of Land Mollusk Faunal Inventories in Montana. Only a few publications provide accounts of the extant land mollusk faunas in Montana. Elrod (1902) presented the first (and apparently only) list of known species for the state, while recognizing that the list was necessarily incomplete due to inadequate collecting over much of the area, a problem persisting to this day. Elrod' s (1902) report included brief mention of three species of conservation concern {Pyramidula [=Oreohelix] elrodi, Pyramidula [=Oreohelix] alpina, and Polygyrella polygyrelld) in western Montana, and included the records of Squyer (1984) from the Wibaux area (known as Mingusville), which represented essentially the only information from the eastern parts of Montana at that time. Shortly thereafter. Berry (1916) published a summary of his collecting efforts in Meagher and Fergus counties, incorporating his earlier and briefer report (Berry 1913) and including an account of Oreohelic strigosa berryi in the Big Snowy Mountains. At this same time, Vanatta (1914) published a list of species collected by L. E. Daniels in the Bitterroot Mountains, which included the first records of the endemic slug Hemphillia danielsi. Little else appeared in print for some time, until Russell and Brunson (1967) compiled what was known about the mollusk fauna of Glacier National Park, which updated an earlier report by Berry (1919) and included many new observations by the authors. The Russell and Brunson (1967) list is probably the most complete for any area of significant size in Montana. Interestingly, none of the land mollusks of state conservation concern have been documented in Glacier National Park. Unfortunately, Brunson (who qualified as the most knowledgeable malacologist residing in Montana for the second half of the 20* Century) never wrote a revision of Elrod' s (1902) out-dated state list, even though several additional species were known to occur in Montana by the time Brunson retired from active collecting in the early 1980's. The records of new terrestrial mollusk species and locations for Montana, including several of conservation concern, remain scattered in publications of more narrow scope, many of them now decades old (e.g., Bartsch 1916, Pilsbry and Brunson 1954, Brunson and Osher 1957, Brunson and Russell 1967, Fairbanks 1984), or deposited as vouchers in museum collections and otherwise unpublished. Fortunately, most or all of the species of greatest conservation interest in Montana are discussed in Frest and Johannes (1993, 1995) as part of mollusk assessments of the Black Hills and the Interior Columbia River Basin, respectively. Most recently (beginning in 1997), additional brief surveys for a few species have been made by Montana Natural Heritage Program zoologists, who also continue to solicit and accumulate opportunistic observations of mollusks for the Heritage databases, with focus on species of conservation concern as identified in the documents of Frest and Johannes (1993, 1995). Distribution and Status of Species of Conservation Concern. A review of available literature and unpublished reports, museum records, personal discussions and field survey results provided only 66 locality records (see Appendix B) for the set of 1 5 terrestrial mollusk taxa of conservation concern listed in Table 1 (note that a subspecies of slug, Udosarx lyrata russelli, is discussed in the account of the species). Three snails {Discus shimeki, Oreohelix strigosa berryi, Oreohelix yavapai mariae) are known from sites east of the Continental Divide; the remaining taxa, including all of the listed slugs, are known only from sites west of the Continental Divide. No taxon has been reported in Montana at as many as 15 total localities, and only two {Oreohelix strigosa berryi and Radiodiscus abietum) have been documented at as many as ten. Two taxa {Discus brunsoni and Oreohelix yavapai mariae) remain known from single localities each, five others {Oreohelix alpina, Oreohelix amariradix, Oreohelix carinifera, Oreohelix elrodi, and Udosarx lyrata) from two to four localities each. All but one terrestrial mollusk species, the Mission Range Disc {Discus brunsoni), on the joint Montana Natural Heritage Program-Montana Department of Fish, Wildlife and Parks Animal Species of Concern list (Carlson 2003) have been documented on or near at least one National Forest unit in the Northern Region of Montana (Table 2). Other National Forests not listed in Table 2 are likely to support one or more terrestrial mollusk species of conservation concern, given the wide distribution of some of these, such as the Striate Disc {Discus shimeki) and Berry's Mountainshell {Oreohelix strigosa berryi). Many of the listed National Forests are likely to support additional taxa of conservation concern not yet documented on their lands. Table 2. Terrestrial mollusk Species of Concern or On Review (Carlson 2003) that have been documented on National Forest lands of the Northern Region (Region 1). Species in brackets ([ ]) indicate a species that has been documented < 2 km from a particular forest boundary. Forest Mollusk Species Beaverhead-Deerlodge Zacoleus idahoensis Bitterroot Hemphillia danielsi, Radiodiscus abietum, Udosarx lyrata Flathead Magnipelta mycophaga, Oreohelix alpina, Oreohelix elrodi Gallatin Discus shimeki, Oreohelix strigosa berryi, Oreohelix yavapai mariae Kootenai (including Kaniksu in Montana) Discus shimeki, Magnipelta mycophaga, Radiodiscus abietum, Zacoleus idahoensis Lewis and Clark Oreohelix strigosa berryi Lolo {Hemphillia danielsi], Magnipelta mycophaga, Oreohelix amariradix, Oreohelix carinifera, Polygyrella polygyrella, Radiodiscus abietum, Zacoleus idahoensis These scant results lead to two conclusions: 1) most species/subspecies of special concern are very rare, existing in small, often isolated populations, and 2) survey coverage in Montana has been woefully inadequate to provide a reasonable assessment of the distribution and status of most or all taxa. Field surveys and opportunistic observations indicate both conclusions probably are reasonable. With very limited resources, Heritage Program zoologists have documented four priority species at nine new localities (of the 66 total localities for all priority species) since 1997, and determined that populations of three species remain extant at five additional localities not sampled in the previous 30 years (see Appendix B). A new locality (one of three) for the Carinate Mountainshell (Oreohelix elrodi) was discovered in 1999; two of five total Montana localities so far documented for the Marbled Jumping Slug {Hemphillia danielsi) were reported first in 2001 by other biologists. Thus, very brief field surveys and opportunistic encounters in recent years have significantly increased the number of localities where terrestrial mollusks of conservation concern have been found. Nonetheless, some species (especially several species oi Oreohelix and Discus brunsoni) have been the focus of numerous searches over the last several decades (Frest and Johannes 1995, R. B. Brunson pers. comm.) with few or no new populations discovered. Uncertainty regarding which species are present on National Forests is due to a general lack of the most cursory of inventories to identify the terrestrial mollusk faunas occupying public lands throughout Montana. Thus, to gauge the significance of federal lands for maintaining snails and slugs considered rare and of conservation concern, a priority should be placed on conducting field surveys of appropriate habitats where these species might occur on National Forests of the Northern Region (see Appendix C for guidelines). The evidence from recent field work indicates additional surveys will result in the discovery of several additional populations for some species, most likely the slugs, but most or all mollusk species currently on the Species of Concern lists (Carlson 2003) probably will continue to be identified as relatively rare and of limited distribution in Montana. The discovery of new locations will lead to a reassessment of the status of the listed species in Montana as well as on particular National Forests. However, species new to the known mollusk fauna of Montana are still possible. As an example, a slug species "discovered" (in a museum collection) during the development of this document, the Smokey Taildropper {Prophysaon humile) (see Frest and Johannes 1995), not yet on the joint Montana Natural Heritage Program/Fish, Wildlife & Parks list of "Animal Species of Concern" (Carlson 2003), is now known to be present in Montana (see Appendix C) and will be added to the list in the near future because it is of conservation concern elsewhere in the Interior Columbia River Basin (Frest and Johannes 1995, Niwa et al. 2001). Thus, with additional survey documentation, we can expect that several species will be added to the individual National Forest lists, including some that may not yet be known to occur in Montana. But with continued survey effort we can also anticipate that some species will be dropped from the list of species of conservation concern in Montana because they are known to be more secure than their current ranks indicate. Summary of Occupied Habitats. Generally speaking, the 15 terrestrial mollusk species of conservation interest in Montana (Table 1) fall into two habitat groupings: 1) species often associated with talus or rocky outcrops (Talus Group), and 2) species often associated with moist valley and canyon (ravine) mixed-conifer forests (Moist Forest Group). The two groupings may overlap in some cases; some of the moist mix-conifer forest species are often found in rocky sites, and the talus-inhabiting species may occupy talus imbedded in a forested landscape. But the microhabitats where these two groups occur are usually easy to differentiate. All of the Oreohelix species listed in Table 1, as well as Discus brunsoni, associate with talus or rocky ground, although the occupied sites may range from low-elevation canyons and valley bottoms to high-elevation slopes well above treeline. Sites occupied by this group are typically in terrain that is more open and mesic than where the second group associates. Sites occupied by the second group (the four slugs, Discus shimeki, Polygyrella polygyrella, Radiodiscus abietum) tend to be near permanent water, such as riparian corridors, and in dense conifer forests where there is more precipitation, litter and decaying wood. This group of species also frequents areas with a deciduous wood component of species such as aspen, cottonwood, alder and birch. Potential Threats. No studies exist that document the response of any of the 15 terrestrial mollusk species of conservation concern to disturbance. Threats to populations of these species is largely guess work, and based on the type and extent of habitat alteration and disturbance that has occurred in Montana in the last century. Any kind of habitat alteration that reduces the humidity of the microhabitats where these species occur is a potential threat to both groups, but probably greatest for the Moist Forest Group. Canopy removal through logging and fire are probably the most significant disturbances for the forest-inhabiting species; historical forest clearing has likely resulted in significant reductions and fragmentation of their former ranges. Logging and fire are also potentially significant factors of disturbance for talus-inhabiting species, but talus occupied by these species may be deep enough to provide necessary humidity and temperature regimes that will protect them from logging and fire, at least in some cases and in the short term. However, construction of roads to support logging operations could threaten even some of these seemingly protected talus sites. Grazing has the potential to negatively impact both groups, but some of the species inhabiting talus (especially Discus brunsoni, Oreohelix alpina, and Oreohelix elrodi) are probably largely buffered from grazing impacts due to the specific types of rocky terrain they occupy. For other species in more expose sites, trampling and grazing could devastate the habitat occupied by the snails and slugs, removing plant cover and potential food, and destabilizing occupied slopes. Rural home development and highway and road maintenance also have the potential to contribute to habitat loss for several species in both groups largely restricted to low-elevation valleys and slopes in apparently very localized populations {Oreohelix amariradix and Oreohelix carinifera are examples). Use of chemicals for controlling noxious weeds could present land managers with situations where protection of rare animal species is balanced against the need to control or eradicate exotic pest species, and special effort may be required to assure the protection of the mollusks during these operations. Several of the mollusk species of conservation concern probably occupy areas where control of noxious weeds is desirable, especially along heavily used roads and trails. During the writing of this report it was discovered through conversation with Forest Service personnel that a weed control program will soon occur at the only site known for the Gallatin Mountainsnail (Oreohelix yavapai mariae), A survey of the site should be conducted before spraying to identify the area occupied by the snails, so that disturbance to this rare endemic snail can be avoided. Similar situations such as the above will probably occur in the future as weed control receives more emphasis. This further underscores the need for new surveys to identify sites currently occupied by the terrestrial moUusks of conservation concern discussed in this report. Summary of this report. The species accounts that follow include information on taxonomy and species/subspecies identification (including photographs when available), life history notes on reproductive biology, ecology and habitat associations, information of the range-wide distribution and distribution within Montana (including distribution maps), current abundance, potential or real threats, and land ownership at known localities. In some sections, particularly threats and distributions, what is written is too often speculation. This is unavoidable because so little is known of these topics about most species of conservation concern. A bibliography pertaining to the species of conservation concern, which includes most or all of the published and gray literature mentioning the species that are the focus of this report, is included at the end of the individual species accounts. A table summarizing available geo-spatial data for each occurrence, along with collection/observation dates and museum accession numbers, as well as available habitat information briefly noted, is provided in Appendix B. Guidelines for designing and conducting field surveys are provided in Appendix C. A key to the genera of terrestrial Montana mollusks is provided in Appendix D as an aid to field workers encountering snails and slugs and attempting an initial determination of what they have found. It is hoped that the production of this report will impress upon agency and private sector biologists the magnitude of our ignorance, and spur them to take measures to reduce it. Figure 1. Distribution of Discus brunsoni in Montana. • Discus brunsoni ^^/Continental Divide US Forest Service (Mission Range Disc) ■ ra -4 ^B?^h|'^-' \ - '■ 1 Wm . ms^ SPECIES ACCOUNTS SNAILS SPECIES: Discus brunsoni HeritageRank:Gl,Sl Natural History A. Taxonomy Family: Discidae Discus brunsoni Berry, 1955 Berry (1 955) described this distinctive taxon as a full species. There remain questions regarding its true taxonomic affinities, but complete knowledge will not affect the validity as a full species (see Frest and Johannes 1 995). B. Species Description Morphology: The following description is taken from Berry (1 955). "Shell large for the genus, thin, depressed-conic, with low spire, its slopes weakly convex. Whorls about five and a half, decidedly compressed, moderately rounded both above and below the strongly but not acutely carinate periphery, . . . ; base fiattened, the widely open vorticiform umbilicus contained about three times in the major diameter of the shell; . . . Aperture transversely ovate, compressed, . . . Color near olive-brown, ... the basal surface and that of young shells tending to be a little brighter; no inherent variegation of color pattern evident." Maximum diameter of holotype 10.5 mm, minimum diameter 9. 1 mm; height of shell 4.2 mm, diameter of umbilicus 3.5 mm. Maximum diameters of eight live individuals measured by Hendricks (1 998) ranged from 6.7 mm to 10.5 mm (mean = 9.5 + 1.4 mm). Reproductive biology: Hermaphroditic, so far as known. Internal anatomy is not yet described (Berry 1955, Frest and Johannes 1 995), and there are no descriptions of the reproductive behavior and its seasonal occurrence. Lifespan is unknown. Age/size at maturity is unknown. Ecology: Occupies open, south facing and rather dry talus slopes with very low canopy cover. Vegetation at the margins of the talus slopes includes Douglas-fir (Pseudotsuga menziesii\ ponderosa pine (Pinus ponderosa), pockets of water birch (Betula occidentalis), quaking aspen (Populus tremuloides), and mock orange {Philadelphus lewisii). Rock composition at the type locality was described as limestone (Berry 1 955, Frest and Johannes 1 995), but more recent examination (Hendricks 1 998) revealed the occupied talus to be a mix of diorite and argillite with no limestone present. Apparently this species retreats deep into the talus when surface conditions are unfavorable. Brunson (1956) suggested that D. brunsoni may be crepuscular or nocturnal near the surface, because many collections were made shortly before dusk, or at least in subdued light, following intensive mid-day searches. Hendricks (1 998), however, located live animals at the surface during mid-day when ambient surface conditions were overcast, wet and cool. Oreohelix elrodi is also present in the occupied talus. Foods are unknown, but it may feed most often on plant material on rock surfaces (lichens, etc.) rather than patches of accumulated leaf and conifer needle litter (Brunson 1 956, Hendricks 1 998). C. Range and Known Sites Discus brunsoni is known only from the Mission Mountains in Lake County, northwestern Montana (Fig. 1 , Appendix B). The type locality is the south-facing slope above McDonald Lake in the Mission Mountains Tribal Wilderness of the Confederated Salish and Kootenai Tribes, at about 1 120 m (3700 ft) elevation. Several talus slopes are present above the north shore of the lake; Brunson (1 956) indicates more than one slope is occupied, but Hendricks (1 998) found D. brunsoni only in the talus slope where diorite was abundant. To date, the type locality is the only location where D. brunsoni has been found. Over 70 specimens of this species have been uncovered in seven different years since the first shell was found in August 1 948; the most recent known observation was in July 1 997 (Hendricks 1 998). D. Species Abundance Discus brunsoni is a local endemic, perhaps present only in the Mission Mountains. Because the species occupies large and deep talus slopes it is difficult to make estimates of population size. During favorable surface conditions, Hendricks (1 998) found it to be much less abundant near the surface than sympatric Oreohelix elrodi, another regional endemic of conservation concern. Current Status A. Why Species is of Conservation Concern The Mission Range Disc {Discus brunsoni) is a Species of Concern in Montana because it is a local endemic so far documented at a single site, despite several decades of widespread collecting in the region by Dr. R. B. Brunson and students (Frest and Johannes 1 995, Brunson personal communication). Population size and trends are unknown. Recommended for Federal listing by Frest and Johannes (1 995). B. Threats Although the occupied habitat is not particularly threatened by development or agriculture (logging and grazing), habitat requirements and food habits are poorly understood. Fire suppression efforts (especially use of fire retardants) and talus destabilization (trail maintenance, modification) could have negative impacts. Also, given the trail-side location, weed control efforts could negatively impact the population. 10 C. Distribution Relative to Land Allocations The only known occupied site is in the Confederated Sahsh and Kootenai Tribes Mission Mountains Tribal Wilderness. Amajor hiking and packing trail bisects the site. Additional populations associated with diorite and argillite talus may be present elsewhere in the Mission Mountains on tribal and national forest lands. There are quartz diorite outcrops that should be surveyed in the North Fork and South Fork of Elk Creek drainages in the Flathead National Forest, and near the Crow Creek Lakes in the Mission Mountains Tribal Wilderness. 11 Figure 2. Distribution of Discus shimeki in Montana. • Discus shimeki ^^/Continental Divide US Forest Service 12 SPECIES: Discus shimeki (Striate Disc) Heritage Rank: G4,S1 Natural History A. Taxonomy Family: Discidae Discus shimeki (Pilsbry, 1 890) Originally described from fossil material in Peoria Loess in Iowa. The extant western subspecies, D. s. cockerelli, is considered by some authorities to be indistinguishable from the nominate form (Frest and Johannes 1 993). B. Species Description Morphology: The following description is from Pilsbry (1 948). "The whorls are much more robust than D. cronkhitei. It has a low conic spire, rounded periphery and rather narrowly umbilicate base, the umbilicus contained about 3 .7 to 4 times in the diameter. The first whorl projects somewhat, the first 1 V2 whorls smooth; following whorls regularly and rather strongly rib-striate, . . . [the ribs] become somewhat lower and irregular on the last whorl, where they disappear in the peripheral region, the base being marked only with weak wrinkles of growth." This snail differs from the sympatric Discus cronkhitei (= whitneyi) by its smoother base and weaker ribs on the last whorl. The shell is thin, and brownish in color. Height is about 3 .7 mm, maximum diameter about 6-7 mm; 4.5 whorls. Reproductive biology: Hermaphroditic. Copulation observed in March- June. Egg laying occurs from April- August in the Black Hills; clutch size is relatively small (3-6). Apparently most members of this species have a one-year life cycle (Frest and Johannes 1993). Age/size at reproductive maturity has not been described. Ecology: This species tends to associate with quaking aspen (Populus tremuloides) at Montana sites where habitat was documented (Hendricks unpublished data). Elsewhere in the Rocky Mountains it is also associated with spruce (Picea) and fir (Abies) intermixed with aspen or other broadleaf trees and shrubs (Beetle 1957, 1997, Karlin 1961, Frest and Johannes 1993). Soils often are derived from weathering limestone. D. shimeki is active most often in litter in lowland forest, but sometimes is seen on downed wood and rock surfaces. Slopes are often north-facing and shaded. This species appears to subsist largely on decaying deciduous leaves. C. Range and Known Sites Discus shimeki is widely distributed in the Rocky Mountains of Arizona, New Mexico, Utah, Colorado, and Wyoming, with populations also extant in the Black Hills (Frest and Johannes 1 993). It is also found north of Montana in the Canadian Rockies (Piatt 1 980). Pilsbry (1 948) 13 lists only one Montana location for this species, along the Boulder River in Sweetgrass County (also referenced in Frest and Johannes 1 993). The species has been documented in Montana (Fig. 2, Appendix B) in five counties total (Gallatin, Hill, Lincoln, Park, Sweetgrass), at elevations ranging from 640 m (2 1 00 ft) to 1 940 m (63 60 ft) . The most recent records are from along Beaver Creek in the Bears Paw Mountains, Hill County (1 997) and west of Nurses Lakes (Gallatin National Forest) in the Absaroka Mountains, Park County (2001). D. Species Abundance Population sizes are not reported. The species can be abundant in colonies, but colony sites are relatively small in extent (Frest and Johannes 1 993). At some sites where the species has been documented in Montana, D. shimeki is less abundant than D. cronkhitei (=whitneyi) (pers. obs.). Current Status A. Why Species is of Conservation Concern The Striate Disc {Discus shimeki) is a Species of Concern in Montana because of the limited number of sites where it has been documented in the state, despite several decades of widespread collecting in the region by Dr. R. B. Brunson and students (Frest and Johannes 1 993, 1 995). Recommended for Federal listing by Frest and Johannes (1 993). B. Threats Major threats to known sites include degradation due to timber harvest and livestock grazing, with the latter likely the main threat. Fire is also a concern; stand replacement fires could permanently eliminate populations in isolated colonies (see Beetle 1 997). Response of snails to fire retardants has not been studied. C. Distribution Relative to Land Allocations Known sites in Montana include Forest Service and Tribal lands at widely separated locations. Addition sites are possible on these as well as private lands throughout the montane regions of Montana, including some of the island mountain ranges in the prairie regions east of the main Rocky Mountain chain. None of the sites has special protection. 14 Figures. Distribution of Oreohelix alpina in Montana. • Oreohelix alpina ^^/Continental Divide US Forest Service 16 SPECIES: Oreohelix alpina HeritageRank:Gl,Sl Natural History A. Taxonomy Family: Oreohelicidae Oreohelix alpina (Elrod, 1901) (Alpine Mountainsnail) Originally named Pyramidula strigosa alpina by Elrod (1 90 1 a, 1 903b). Pilsbry (1 939) expressed some doubt about the validity of this taxon, but later examination of material by Frest and Johannes (1995) and Fairbanks (2002) indicate treatment as a full species is appropriate. Pilsbry (1 933) placed Oreohelix alpina with the O. strigosa group, as did Elrod (1 901 a, 1 902, 1 903b), but later (Pilsbry 1 939) moved it to the O. subrudis group. Recent study of the internal anatomy (Fairbanks 2002) indicates affinity with the O. strigosa group. Pilsbry (1 939) placed all Oreohelix in the Xanthonycidae. B. Species Description Morphology : Descriptions of shells from the Mission Mountains are provided in Elrod (1901, 1902, 1903b), Pilsbry (1939), Hendricks (1998), and Fairbanks (2002); reproductive anatomy is described in Fairbanks (2002). Description from Pilsbry (1 939) follows: "shell small; brownish-gray, tending toward light hom color, in dead shells tuming to pearly white; luster somewhat silky; shell flat, little elevated; . . . aperture nearly circular, . . . somewhat higher than wide; markings as in strigosa, the upper band continuing in the spire, gradually disappearing; umbilicus medium, circular, deep, subcylindric." Shell diameter 7-10 mm, average often specimens, 8.91 mm, shell height 3-5mm, whorls 4.0-4.5. Hendricks (1998) reported range in diameter of 1 6 live shells = 2.5-8.5 mm, nine dead shells = 8.0-9.6 mm. Shells from the Swan Range may average slightly larger in diameter: average of 1 3 was 9.4 mm, range 5.7-11.4 mm (Hendricks unpublished data); average of four was 9.3 mm, range 8.5-11 . 1 mm (Fairbanks 2002). Reproductive biology: Hermaphroditic; reproductive anatomy described in Fairbanks (2002). There are no descriptions of reproductive behavior and its seasonal occurrence. Lifespan is unknown. Age/size at reproductive maturity is unknown. Ecology: Occupies open talus slopes at high elevations near and above treeline (Elrod 1 902, 1 903b, Hendricks 1 998). Vegetation at and near the alpine type locality on East St. Marys Peak in the Mission Mountains (Hendricks 1 998) includes the wild flowers snow cinquefoil (Potentilla nivea), mountain avens (Dryas octopetala), alpine sorrel (Oxyria digyna) and moss campion (Silene acaulis). Subalpine fir {Abies lasiocarpa) is present at the margins of the subalpine site above Lower Rumble Lake in the Swan Range (Hendricks unpublished data). Rock substrate at all known sites is limestone. Live shells are found on surfaces of limestone 17 blocks, but often in the absence of direct sunlight (shaded areas and undersides of smaller blocks). Block size where O. alpina was found on St Marys Peak averaged 20 x 30 cm square and 4-8 cm thick (Hendricks 1 998), block size at the Swan Range site ranged from 1 5 x 1 5 X 4 cm to 1 m^ (Hendricks unpublished data). Some soil development and leaf litter was present at each site where live snails were found; one group of live snails was found in leaf litter near the base of snow cinquefoil partially protected overhead by rock. Food habits are unknown. C. Range and Known Sites Oreohelix alpina is known from three sites (Fig. 3, Appendix B) in two counties (Elrod 1 902, 1 903b, Hendricks 1 998, Fairbanks 2002). The type locality is East St. Marys Peak in the Mission Mountains of Lake County, from 2710m (8900 ft) to 2865 m (9400 ft) elevation. The second site in the Mission Mountains is more extensive, and includes West McDonald Peak, the summit area of McDonald Peak, and the slopes of McDonald Peak above Duncan Lake, all in Lake County, from 2255 m (7400 ft) to 2957 m (9700 ft) elevation. The third site is above Lower Rumble Lake in the Swan Range, Missoula County, at 21 95 m (7200 ft) elevation. The known sites have been visited infrequently, probably because of difficult access. Prior to 1 997, the species had not been reported at either Mission Mountains site since 1 952 (specimen in the Field Museum of Natural History, Chicago), and there remain few collections of this species. The Swan Range site was not discovered until 1 975, and O. alpina had not been documented again at this locality until 2000. Other sites within each mountain range are likely to exist. Additional populations may be discovered in portions of the Bob Marshall Wilderness. D. Species Abundance Oreohelix alpina is a local endemic restricted to the Mission Mountains and nearby Swan Range. The species was relatively abundant at some locations within sites of occurrence (Elrod 1 902, Hendricks 1 998). However, no population estimates are available, and nothing is known regarding population trends at any site. Current Status A. Why Species is of Conservation Concern The Alpine Mountainshell {Oreohelix alpina) is a Species of Concern in Montana because it is a local endemic so far documented at three sites, despite several decades of widespread collecting in the region by Dr. R. B. Brunson and students (Frest and Johannes 1 995). Population size and trends are unknown. Recommended for Federal listing by Frest and Johannes (1995). 18 C. Threats Occupied habitat (alpine and high-elevation limestone talus) is not threatened by current land use practices. Probably the greatest threat to species persistence is climate change. C. Distribution Relative to Land Allocations The two known sites in the Mission Mountains are in the Confederated Salish and Kootenai Tribes Mission Mountains Tribal Wilderness. The Swan Range site is on the Flathead National Forest (Swan Lake Ranger District). Additional populations are possible on adjacent Tribal and Forest Service lands. 19 Figure 4. Distribution of Oreohelix amariradix in Montana. • Oreohelix amariradix ^^/Continental Divide US Forest Service 20 SPECIES: Oreohelix amariradix (Bitterroot Mountainsnail) Heritage Rank: G1G2, S1S2 Natural History A. Taxonomy Family: Oreohelicidae Oreohelix amariradix Pilsbry, 1 934 Originally identified by Elrod ( 1 90 1 a, 1 902, 1 903b) as a "small variety" of Oreohelix (=Pyramidula) strigosa from the Bitterroot Mountains, but described by Pilsbry (1 933) as a full species of the O. strigosa group, based only on dead shells. Fairbanks' (1980) analysis of the internal anatomy confirmed Pilsbry 's designation. Pilsbry (1 939) placed all Oreohelix in the Xanthonycidae. B. Species Description Morphology: Pilsbry (1 933, 1 939) describe the shell as "openly umbilicate, the umbilicus contained about 4 times in the diameter; biconvex with the periphery rather sharply angular, the angle disappearing on the last third of a whorl. Whorls 51/3, the embryonic 21/3 moderately convex and nearly smooth. Susequent whorls rather coarsely and irregularly wrinkle-striate, without spiral striation, but there is often a spiral impression above the suture on the penult whorl. The last whorl descends shortly in front. Aperture rather strongly oblique, . . . The specimens . . . show a reddish band immediately below the periphery, another a short distance above it." Shell height 8.5 mm, diameter 14.5 mm. Elrod (1 903b) gives height of 1 0 shells 5.3- 7.4 mm, diameter 1 1 .9-16.7 mm; number of whorls 4.8-5.4. Fairbanks (1980) gives height of 6.9-10.9 mm and diameter of 1 2.8- 1 7.9 mm for 2 1 specimens from another site nearby; number of whorls 4.75-5.5. Reproductive biology: Hermaphroditic (Fairbanks 1980). No description of reproductive behavior and its seasonal occurrence in natural settings. Life span is unknown. Age/size of reproductive maturity is not described; in captivity young bom live after adults overwintered. Ecology: This species occupies small talus slides, primarily the basal portions (Frest and Johannes 1995), scattered among open grassy, south-facing slopes that become quite dry in mid-summer (Elrod 1903b, Fairbanks 1980). Vegetation at one site included bunch grasses, ponderosapine {Pinus ponderosa), serviceberry (Amelanchier alnifolia), and ninebark (Physocarpus malvaceus). Food habits are unknown. C. Range and Known Sites Oreohelix amariradix is known only from the Lolo Creek drainage near Fort Fizzle, Missoula County (Fig. 4, Appendix B) at about 1 070 m (3500 ft) elevation. Elrod (1 903b) gave the 21 elevation at the type locality as 1 524 m (5000 ft), but this is likely an error, as Lolo Pass is < 100 m elevation above this contour, nor does habitat at that elevation fit the description. Reported records along the Clark Fork River at Ravenna and Nimrod (Frest and Johannes 1 995) appear to be an error, perhaps confiised with locations for O. carinifera (see next species account), as no documentation was found for O. amariradix at these sites. The known sites have been visited infrequently. Attempts by Frest and Johannes (1 995) to locate living animals in 1 994 were unsuccessful, although these authors state that the species is extant at two Lolo Creek drainage sites. Given their comments, and earlier ones by Elrod (1901), populations other than those listed in Appendix B may exist in the Lolo Creek area. D. Species Abundance Oreohelix amariradix is a local endemic restricted to the Bitteroot Mountains. There are no published estimates of population size or relative abundance. There may be an overall declining trend in absolute abundance, given Frest and Johannes' (1 995) comments about local extinctions. Current Status A. Why Species is of Conservation Concern The Bitterroot Mountainshell {Oreohelix amariradix) is a Species of Concern in Montana because it is a local endemic so far documented only in the Lolo Creek drainage , despite several decades of collecting in the region by Dr. R. B. Brunson and students (Frest and Johannes 1 995). Population size and trends are unknown. B. Threats Habitat occupied by Oreohelix amariradix (low elevation talus in slopes of open ponderosa pine) is threatened by logging, grazing, weed control, highway development, home development, and fire. The impact of fire retardant on this and other terrestrial moUusks in not known. Little is known about this species, including its susceptibility to disturbance. C. Distribution Relative to Land Allocations The known sites (Appendix B) are on or near Lolo National Forest lands, as well as private timber company lands. It is quite possible that additional populations occur on both, as well as other private lands. None of the sites have special protection. 22 Figures. Distribution of Oreohelix carinifera in Montana. • Oreohelix carinifera ^^/Continental Divide US Forest Service 24 SPECIES: Oreohelix carinifera (Keeled Mountainsnail) HeritageRank:Gl,Sl Natural History A. Taxonomy Family: Oreohelicidae Oreohelix carinifera Vilsbry, 1912 Affinities of this species are with the Oreohelix yavapai group (Pilsbry 1933, Frest and Johannes 1 995), and based primarily on the intemal anatomy. Pilsbry (1 939) placed all Oreohelix in the Xanthonycidae. B. Species Description Morphology: Pilsbry (1912, 1933, 1939) describes the shell as "lenticular, carinate, umbilicate, the umbilicus contained 41/3 times in the diameter. The whorls increase slowly, the first 2 Yi strongly convex, the rest strongly convex around the upper (inner) part, becoming concave near the outer (peripheral) edge. The embryonic whorls are very finely obliquely striate; later whorls rather coarsely wrinkle-striate, with some weak spiral striae in places; the last whorl is concave above and below the peripheral keel, descends very little or not at all in front, . . . The aperture is about as high as wide, and shows a slight angle at the end of the keel." Shell diameter 9-12 mm; shell height 5-7 mm; whorls 4/^-5. The intemal anatomy is described in Pilsbry (1 933, 1939). Reproductive biology: Hermaphroditic (Pilsbry 1933, 1939). There is no description of reproductive behavior and its seasonal occurrence. Life span is unknown. Age/size at reproductive maturity is unknown. Ecology: This species occupies small limestone outcrops and sandy limestone soils on arid slopes with sparse vegetation cover; described sites have been south facing (Frest and Johannes 1 995, L. Fairbanks personal communication). Vegetation at sites includes open stands of sagebrush (Artemisia)/}unvpQY (Juniperus) and Douglas-fir (Pseudotsuga menziesii). Individuals have often been found under shrubs and junipers. Food habits are not described. C. Range and Known Sites Oreohelix carinifera is known in Montana from four sites in the Clark Fork River drainage, Powell and Granite counties (Fig. 5, Appendix B) at 1 250- 1 480 m (4 1 00-4850 ft) elevation. Frest and Johannes (1 995) found the species at a portion of the type locality at Garrison, but failed to at another former location near Beavertail Hill where the species was present in 1 975. There have been few or no additional searches for this species at former sites in recent years. 25 In August 2002, however, dead shells were found at a new site in the Garnet Range (personal observation), indicating that additional sites are possible. Both Pilsbry (1 939) and Frest and Johannes (1 995) listed O. carinifera as endemic to Montana, but the species is on the Wyoming checklist (Beetle 1 989) for Park County. Interestingly, Beetle ( 1 96 1 ) earlier identified this species from the Big Horn Mountains in Big Horn and Washakie counties, of which neither location appeared on her 1 989 state checklist. It is assumed in the present report that Oreohelix carinifera is a local endemic in Montana, as stated by Frest and Johannes (1 995); the Wyoming material needs reexamination by experts for final determination, as there are other small Oreohelix species present in that portion of Wyoming with which O. carinifera might be confused. D. Species Abundance Oreohelix carinifera is a local endemic restricted to the upper Clark Fork River drainage. There are no published estimates of population size or relative abundance. Pilsbry (1912) noted that where the shells were "so abundant as to attract the attention of non-conchological naturalists" (p. 88) there are plenty of living snails to be found nearby (the first collection was made by two entomologists). Frest and Johannes's (1 995) limited success at locating the species in the last decade, including finding dead shells where live ones were absent, suggests that population sizes may be in recent decline, with possible extinctions at some sites. Current Status A. Why Species is of Conservation Concern The Keeled Mountainshell {Oreohelix carinifera) is a Species of Concern in Montana because it is a local endemic so far documented only in the upper Clark Fork River drainage between Garrison and Missoula, despite several decades of collecting in the region by Dr. R. B. Brunson and his students (Frest and Johannes 1 995). Population size and trends are largely unknown. B. Threats Habitat occupied by Oreohelix carinifera (low-elevation slopes of open juniper and Douglas- fir) is threatened by logging, grazing, weed control, highway development, home development, and fire. The impact of fire retardants on this and other terrestrial moUusks in not known. Little is known about this species, including its susceptibility to disturbance. C. Distribution Relative to Land Allocations The known sites are on or near private timber land, Lolo National Forest land, state land. Bureau of Land Management land, and private non-timber land. None of these sites have special protection. 26 Figure 6. Distribution of Oreohelix eirodi in Montana. • Oreohelix eirodi ^^/Continental Divide US Forest Service 28 SPECIES: Oreohelix elrodi (Carinate Mountainsnail) HeritageRank:Gl,Sl Natural History A. Taxonomy Family: Oreohelicidae Oreohelix elrodi (Vilshry, 1900) Originally named Pyramidula elrodi by Pilsbry (1900). AflFmities of this species are with the Oreohelix strigosa group (Pilsbry 1933, Frest and Johannes 1995), based on the internal anatomy (see Pilsbry 1939); additional description of the intemal anatomy is available in Fairbanks (1 984). Pilsbry (1 939) placed all Oreohelix in the Xanthonycidae. B. Species Description Morphology: Pilsbry (1900, 1939) describes the shell as "strongly depressed, biconvex, acutely carinate, with open umbilicus contained about 4 times in the diameter; pale vinaceous fawn color to nearly white (under a fugacious light brownish cuticle which is lost in all adult shells seen). Spire low conoidal, often much depressed. Embryonic shell of 2 1/3 to 2 2/3 whorls, the first smooth, the rest varying from unevenly striate to finely costellate. Later whorls are coarsely sculptured with rude, unequal, retractive ribs, usually narrower than their intervals, which are densely and finely striate spirally The last whorl descends shortly in front. Aperture angular at termination of the keel." Shell diameter21-28 mm (Pilsbry 1939), 17.4-26.0 mm (Fairbanks 1984), 4. 1-22.6 mm (Hendricks 1998); shell height 8.8-13.3 mm (Pilsbry 1939), 8.4-13.1 mm (Fairbanks 1984); whorls 5-5 V2 (Pilsbry 1939), 5-5 Va (Fairbanks 1984). Shell diameter of new-bom young 3.6-3.7 mm; whorls 2.3-2.5 (Hendricks unpubhshed data). The intemal anatomy is described in Pilsbry (1 939) and Fairbanks (1 984). Reproductive biology: Hermaphroditic (Pilsbry 1939, Fairbanks 1984). There is no description of reproductive behavior and its seasonal occurrence. Life span is unknown. Age/size at reproductive maturity is unknown; a captive adult 1 8.2 mm diameter gave birth to 4 young after overwintering (Hendricks unpublished data). Ecology: This species occupies course talus, typically on south-facing slopes, and usually with sparse canopy of ponderosapine {Pinus ponderosa), mountain ash (Sorbus) and serviceberry (Amelanchier) (Frest and Johannes 1 995). Hendricks (1 998) described vegetation at three talus sites in the Mission Range, each with 0% canopy cover in the search areas, as bordered by Douglas-fir (Pseudotsuga menziesii) and ponderosa pine with pockets of water birch (Betula occidentalis), quaking aspen (Populus tremuloides) and mock orange (Philadelphus lewisii). At the two Swan Range locations, portions of the occupied terrain (Hendricks unpublished data) are in talus under a forest canopy variably composed (depending on 29 microsite) of Douglas-fir, ponderosapine, quaking aspen, western red cedar (Thuja plicata), paper birch (B. papyrifera) and western larch (Larix occidentalis); canopy cover is 0-10%. Elrod (1 902) considered O. elrodi to be "a shell of the rocks" (p. 1 1 7), present on the surface of exposed talus during favorable conditions, and present down among the stones when conditions become dry (Elrod 1903 a). During favorable surface conditions (wet, 10-17°C) live individuals are found attached to rocks near the surface but more often are present on organic litter accumulations within the talus; some aestivating mature individuals (18-21 mm diameter) are found near the talus surface during dry and warm (2 1 -23°C) conditions (Hendricks 1 998). Food habits are not described, but presence on organic litter indicates O. elrodi may be a detritivore. Occupied talus at the Mission Range site is described by Berry (1 955) and Frest and Johannes (1 995) as limestone. However, Hendricks (1 998) found O. elrodi in this mountain range at sites comprised mostly of diorite and/or argillite; rock type at the two occupied sites in the Swan Range is also argillite (Hendricks unpublished data). Clast (fragment) size of the rocks comprising occupied talus ranges from 1 0 x 20 x 1 0 cm to 1 m^ at the Mission Range sites (Hendricks 1 998), and 1 0 x 1 0 x 1 0 cm to 0.5 x 0.5 x 0.5 m at the Swan Range sites (Hendricks unpublished data). Measured slope at occupied sites in both mountain ranges was 25-36° (Hendricks 1 998, unpublished data). How deep into talus slopes this species occurs is unknown, but live individuals were found up to a meter below the surface at the Mission Range microsite co-occupied by Discus brunsoni (see Hendricks 1998). C. Range and Known Sites Oreohelix elrodi is endemic to northwestern Montana, known from three sites in Lake County: one (the type locality) in the McDonald Lake cirque on the west side of the Mission Range at 1 067-1 524 m (3500-5000 ft) elevation (Elrod 1 902 states shells occur up to 2286 m or 7500 ft elevation), two on the west side of the Swan Range at 1 1 58-1295 m (3800-4250 ft) elevation along Lion and Goat creeks (Fig. 6, Appendix B). Live animals were found at the type locality in the Mission Range as recently as 1 997 (Hendricks 1 998), and in 1 999 at both the Lion Creek site and the Goat Creek site (which was discovered in 1 999). There have been few or no additional searches for this species at the above sites, and no additional surveys for new localities in either mountain range. D. Species Abundance Oreohelix elrodi is a local endemic restricted to the Mission and Swan ranges. There are no published estimates of population size. Elrod (1901-1902, 1902, 1903 a) stated dead shells were abundant in many locations on the slopes above McDonald Lake but live animals were relatively uncommon sometimes. Live O. elrodi were 4-6 times more abundant than Discus brunsoni near the talus surface in the microsite where the two species are sympatric. Among the three sites, live individuals were found at a rate of 0. 1 67/min on 1 July at the type locality co-occupied by D. brunsoni, 0. 1 74/min on 1 9 May at Lion Creek, and 0.350/min on 9 June at Goat Creek; conditions were overcast, wet and 7-1 FC at the time of the searches (Hendricks 30 1 998, unpublished data). Population trends are unknown, but the species has persisted at the type locality for a century following its discovery in 1 899 (Elrod 1 903a). Current Status A. Why Species is of Conservation Concern The Carinate Mountainshell (Oreohelix elrodi) is a Species of Concern in Montana because it is a local endemic so far documented at only three sites in the Mission and Swan ranges of Lake County, despite several decades of collecting in the region by Drs. M. J. Elrod and R. B. Brunson and their students (Frest and Johannes 1 995). Population size and trends are unknown. B. Threats Habitat occupied by Oreohelix elrodi (low-elevation slopes of mixed conifers, especially Douglas-fir, ponderosa pine and western larch) is threatened to some extent by logging, grazing, and fire, although occupied habitat is often in talus surrounded by mixed coniferous forest. Habitat requirements and food habits are poorly understood, however. Fire suppression efforts (especially use of fire retardants) and talus destabilization (trail maintenance, modification) could have negative impacts, as could chemical control of weeds. C. Distribution Relative to Land Allocations The type (and only) locality in the Mission Range is in the Confederated Salish and Kootenai Tribes Mission Mountains Tribal Wilderness. A major hiking and packing trail bisects the site. The Lion Creek site in the Swan Range occupies lands administered by Plum Creek Timber Company and the Swan Lake Ranger District of the Flathead National Forest; a major hiking trail bisects the site. The Goat Creek site in the Swan Range occupies lands administered by the Swan Lake Ranger District of the Flathead National Forest. It is a small talus patch just upslope from FS Road 9530 in an area where logging has occurred previously. 31 Figure 7. Distribution of Oreohelix strigosa berryi in Montana. • Oreohelix strigosa berryi ^^/Continental Divide US Forest Service 32 SPECIES: Oreohelix strigosa berryi (Berry's Mountainsnail) Heritage Rank: G5T2, S1S2 Natural History A. Taxonomy Family: Oreohelicidae Oreohelix strigosa berryi (Pilsbry, 1915) Originally described as a subspecies oi Oreohelix cooper i but changed in 1 933 to a subspecies of O. strigosa (Pilsbry 1933, Henderson 1936), with cooper i also reduced to a subspecies of O. strigosa. External and internal anatomy indicates O. strigosa berryi is distinct to the subspecies level (Pilsbry 1933, 1939, Frest and Johannes 1993). Beetle (1989) considered this subspecies a form of O. pygmaea, but Frest and Johannes ( 1 993) separate the forms in the Black Hills on the basis of shell morphology. Pilsbry (1 939) placed all Oreohelix in the Xanthonycidae. B. Species Description Morphology: Pilsbry (1939) describes the shell as having " the same shape characteristic of O. cooperi except that the last whorl is distinctly angular in front, the angle disappearing on the last half or third, leaving the periphery rounded. Color cinnamon to snuff brown, from third whorl profusely marked with white patches and narrow streaks; last whorl having a chocolate band below the periphery . . . The surface is irregularly striate and shows traces of spiral striation in places. Whorls 41/3, all convex. Embryonic shell of nearly two whorls, which are finely striate and covered with very fine spirals, the last half of the second whorl having distinct spiral striae. Umbilicus narrow, contained 5 Yi times in the diameter of the shell" (p. 445-446). Frest and Johannes (1 993) add "full adult with about 5-5 1/4 whorls; shell low dome-shaped . . ." (p. 76). Shell diameter 7-13 mm (types 9.3 and 9.4 mm); shell height of types 6. 1 and 6.3 mm (Pilsbry 1939). Intemalanatomy described in Pilsbry (1933, 1939). Reproductive biology: Hermaphroditic (Pilsbry 1933, 1939). There is no description of reproductive behavior and its seasonal occurrence. Life span is unknown. Age/size at reproductive maturity is unknown. Ecology: Found among small loose rock, shrubbery, and under creeping juniper (Juniperus horizontalis) on west-facing canyon slopes at the type locality in the Big Snowy Mountains, and under sticks and logs in moister locations in the same mountain range (Berry 1916). This snail was present in the Mammoth area of Yellowstone National Park on a north exposure of limey soil with plenty of cover, but neither very wet nor dry (Henderson 1 936). Substrate typically is derived from limestone (Frest and Johannes 1 993, 1 995). In the Black Hills and Bear Lodge Mountains of Wyoming and South Dakota, it occurs in mixed and open ponderosa pine {Pinus ponderosa) forests with relatively thin litter, often with aspen (Populus 33 tremuloides) and birch (Betula) in the canopy, and violets (Viola) and Canada dogwood (Cornus canadensis) in the understory (Frest and Johannes 1 993); the deciduous tree component was relatively important for the occurrence of this subspecies. C. Range and Known Sites Oreohelix strigosa berryi is documented from several locations in and near the Big Snowy Mountains of Fergus and Golden Valley counties, Montana (Fig. 7, Appendix B), and more recently (Hendricks unpublished data) from the Judith Mountains, also in Fergus County, and the vicinity of Montanopolis in the Absaroka Mountains, Park County (Frest and Johannes 1995); elevation ranges from 1295-2438 m (4250-8000 ft). Also documented in Wyoming in Yellowstone National Park near Mammoth (Henderson 1933,1936, Pilsbry 1 93 9) and in the Black Hills National Forest of Wyoming and South Dakota (Frest and Johannes 1 993). D. Species Abundance Oreohelix strigosa berryi in Montana has been fully documented only in the Big Snowy Mountains. Population sizes are not reported for any of the Montana locations, nor have most of these sites been revisited in recent decades. Berry (1916) found it to be the most conspicuous land snail near the mouth of Swimming Woman Creek Canyon in the Big Snowy Mountains. Colonies outside of the Big Snowy Mountains generally appear to be small and isolated (Frest and Johannes 1 993), although the recent collection of shells in the Judith Mountains (Hendricks unpublished data) indicate colonies, some fairly large, may be present in some of the other "island mountains ranges" of eastern Montana. Henderson (1 936) said the species occurred in abundance near Mammoth in Yellowstone National Park, Wyoming. Population trends are unknown for any locality. Current Status A. Why Species is of Conservation Concern Berry's Mountainshell {Oreohelix strigosa berryi) is a Species of Concern in Montana because it is a relict subspecies so far documented in Montana at ten localities in three mountain ranges, and only present in two additional areas outside of Montana in Wyoming and South Dakota (Yellowstone National Park, Black Hills National Forest) despite several decades of collecting in the region by Dr. R. B. Brunson and Stillman Berry. Population size and trends in Montana are unknown, but outside of Montana where intensive surveys have been undertaken in recent years (Frest and Johannes 1 993) this subspecies appears to exist in only a few small colonies. B. Threats Habitats occupied by Oreohelix strigosa berryi are may be threatened by logging and grazing, and possibly weed control and mining, but most documented localities have not been revisited in decades, so current threats are unknown. Fire and fire suppression efforts could have negative impacts (numerous dead shells found in the Judith Mountains were in a decade-old bum). 34 Logging and grazing threaten the Black Hills National Forest colonies (Frest and Johannes 1 993). Habitat requirements and food habits are poorly understood. Colonies may be local and small. C. Distribution Relative to Land Allocations The type locality (Swimming Woman Creek Canyon) and all other known locations (six total) in the Big Snowy Mountains are on lands administered by the Musselshell Ranger District of the Lewis and Clark National Forest. Two other sites north of the Big Snowy Mountains apparently are on private and possibly state land. The site in the Judith Mountains is on land administered by the Lewistown Field Office of the Bureau of Land Management. The Park County site is on land administered by the Livingston Ranger District of the Gallatin National Forest. 35 Figures. Distribution of Oreohelix yavapai mariae in Montana. • Oreohelix yavapai maria^ ^^/Continental Divide US Forest Service 36 SPECIES: Oreohelix yavapai mariae (Gallatin Mountainsnail) HeritageRank:G4?Tl,Sl Natural History A. Taxonomy Family: Oreohelicidae Oreohelix yavapai mariae Bartsch, 1916 The original description of this taxon by Bartsch (1916) and his placement as a subspecies of Oreohelix yavapai are still valid. Pilsbry (1 939) and Frest and Johannes (1 995) consider this taxon distinct from another subspecies, O. yavapai extremitatis, that is present in the Big Horn Mountains, Wyoming, and the nearby Bridger Range, Montana. Pilsbry (1 939) placed all Oreohelix in the Xanthonycidae. B. Species Description Morphology: Bartsch (1916) describes the shell as "decidedly depressed helicoid, almost lenticular, flesh colored, with a narrow brown band on the upper surface, which is a little nearer the peripheral cord than the suture, and a second even narrower one bordering the peripheral cord on the lower surface. Nuclear whorls scarcely differentiated from succeeding turns, bearing the same sculpture as the adult whorls, but a little less strongly expressed. Periphery of the whorls provided with a cord-like keel, which becomes somewhat weakened on the last quarter of the last turn. Entire surface both above and below marked by slender thread-like incremental lines and fine spiral striations; last whorl slightly descending near the aperture. Base broadly, openly umbilicated, well rounded; a little more convex at the umbilical wall than at the lateral margin. Aperture very oblique, oval; peristome neither thickened nor refiected at the edge; parietal wall strong, rendering the peristome complete" (p. 331). Shell diameter 20.7 mm (1 8.3-22.5 mm; n = 9); shell height 9.2 mm (8.2-1 0.0 mm; n = 9); number of whorls 5.5 (5.2- 5.6; n = 9). Internal anatomy not described. Reproductive biology: Presumably hermaphroditic, but the intemal anatomy is not described. There is no description of reproductive behavior and its seasonal occurrence. Life span is unknown. Age/size at reproductive maturity is unknown. Ecology: Present on a south-facing slope in grassy habitat near the base of a limestone outcrop (L. Fairbanks personal communication). Nothing else about the ecology of this species is known or described. C. Range and Known Sites Known only from the type locality at Squaw Creek near the mouth of Gallatin Canyon in the Gallatin Range, Gallatin County, Montana (presumably above the confiuence of Squaw Creek 37 with the Gallatin River) at 1 707 m (5600 ft) elevation (Fig. 8, Appendix B). D. Species Abundance No inft)nnation. Specimens have been collected at the type locality as recently as 1 976 (L. Fairbanks personal communication). Population trends are unknown. Current Status A. Why Species is of Conservation Concern The Gallatin Mountainshell (Oreohelix yavapai mariae) is a Species of Concern in Montana because it is known only fi-om a single locality. Decades of collecting across Montana by R. B. Brunson, Stillman Berry, and others have revealed no additional colonies, although additional searches in the Gallatin Range may result in discovery of additional populations. B. Threats Logging and road construction along the Gallatin River and Squaw Creek are likely the main threats that could impact the only known population (Frest and Johannes 1 995). Fire, fire suppression, weed control, and grazing could also have negative impacts. C. Distribution Relative to Land Allocations The only known site is on lands administered by the Bozeman Ranger District of the Gallatin National Forest. 38 Figure 9. Distribution of Hemphillia danieisi in Montana. • Hemphillia danieisi ^^/Continental Divide US Forest Service 40 SLUGS SPECIES: Hemphillia danielsi (Marbled Jumping-slug) Heritage Rank: G1G3, S1S3 Natural History A. Taxonomy Family: Arionidae Hemphillia danielsi Vanatta, 1914 The original species description by Vanatta ( 1 9 1 4, see also Pilsbry 1 948) and placement in the Arionidae are still valid. This species is the eastern-most member of a small genus restricted to the Pacific Northwest. B. Species Description Morphology: Vanatta {\9\AJn Pilsbry 1948) describes Hemphillia danielsi as "sluglike, with the shell partly exposed, and the mantle elevated into a visceral hump, as usual in this genus. The color in formalin is yellowish-gray with bluish-black markings, but in alcohol it is white with black maculations. The shell pore is about one-third the length of the mantle. The posterior part of the foot is narrow, with a dorsal median groove and a tail pore" (p. 747). Length 3 .4 cm (Vanatta 1914, Pilsbry 1948); Pilsbry considered this individual an immature. A recent specimen collected along Mill Creek (Appendix B) measured 6.4 cm (Hendricks unpublished data), and Pilsbry (1948) quotes L.E. Daniels as stating that the living slug is "about two inches [5.1 cm] long, with a high hump showing the shell" (p. 748). In live animals, and some preserved specimens, the tail portion of the foot is laterally compressed, keeled, and tipped with a horn-like projection (Hendricks personal observation; see also photos oiH dromedarius in Ovaska et al. 2002). Internal anatomy is described in Vanatta (1914) and Pilsbry (1948). Reproductive biology: Hermaphroditic, based on internal anatomy; the congeneric Malone Jumping-slug {Hemphillia malonei) is hermaphroditic, but spermatophore delivery is sometimes non-reciprocal (Leonard and Ovaska 2002). There is no description of the reproductive behavior and biology of /Z danielsi, but it may be similar to H malonei for which there exists a recent description of breeding behavior in captivity (Leonard and Ovaska 2002). H malonei captive-raised from eggs reached sexual maturity in the first year. Ecology: There are few descriptions of the habitat occupied by this species. Frest and Johannes (1 995) indicate that moderate-elevation ponderosa pine forest (Pinus ponderosa) is characteristic; moist valley, ravine, gorge, or talus sites are preferred (i.e., low on slopes near water). This description is supported by more recent observations (W. Leonard, B. Maxell, H. Reise personal communications). Each of the correspondents reported finding Hemphillia danielsi in riparian areas very near water (Appendix B). Sites included an overstory of 41 deciduous and coniferous trees and shrubs (Picea engelmanii, Pseudotsuga douglasii, Populus, Alnus). Rock or soils at known sites have not been described, but igneous rock types dominate the range of this species. C. Range and Known Sites Hemphillia danielsi is virtually a Montana endemic known only from the eastern side of the Bitterroot Mountains in Ravalli County (Fig. 9, Appendix B), with the exception of one or two records a short distance west of the Bitterroot crest into Idaho (see below); the type locality is at Camas Creek. Five total sites in Montana have been documented, from Mill Creek in the north to Medicine Hot Springs in the south at elevations between 1341-1 524 m (4400-5000 ft). Two of the five sites (Bunkhouse Creek, Mill Creek) were first discovered in 2001 . Additional populations in the Bitterroot Mountains are likely to be discovered as more surveys are conducted. Hemphillia danielsi has been documented infrequently in surveys on the Idaho side of the Bitterroots (Frest and Johannes 1 995); the first Idaho record apparently is that of Webb (1959) near Lolo Pass, and Hemphillia collected more recently at the confiuence of Apgar Creek with the Lochsa River in Idaho County may be this species (W. Leonard personal communication). D. Species Abundance No information. Animals were collected at the type locality as recently as 2001 (H. Reise personal communication), four individuals were found at the Bunkhouse Creek site in 200 1 , two individuals at the Mill Creek site in 2001 (W. Leonard, B. Maxell personal communications). Current Status A. Why Species is of Conservation Concern The Marbled Jumping-slug {Hemphillia danielsi) is a Species of Concern in Montana because it is nearly a Montana endemic so far documented at but five sites in the Bitterroot Mountains of Ravalli County, despite several decades of collecting in the region by Dr. R. B. Brunson and students (Frest and Johannes 1 995). Population sizes and trends are unknown. B. Threats Habitat occupied by Hemphillia danielsi (moderate elevation mixed conifer forest, often near water) is threatened by logging, grazing, fire, and possibly weed control and rural home development. The impact of fire retardant on this and other terrestrial moUusks is not known. Little is known about this species, including its sensitivity to disturbance. 42 C. Distribution Relative to Land Allocations Probably four, and possibly all, of the known sites in Montana (Appendix B) are on lands administered by the Stevensville, Darby, and Sula Ranger Districts of the Bitterroot National Forest. The specific collection site at Medicine Hot Springs is uncertain and may be on private land. 43 Figure 10. Distribution of Magnipelta mycophaga in Montana. • Magnipelta mycophaga ^^/Continental Divide US Forest Service 44 ^^H^ ^^^^H ?^i^^^^^^9^^^^^^^^^^l ^^^^^^^^Hi^^^LVf MlRSLF^i^^^^^^l ^^^^^^^^HRr l^F^ Hi^^ F-_ ^^j fc 'L_Ji^3Liia l^^^^^^^^B '•' '^\^^^^| '■jAmW^^HH SPECIES: Magnipelta mycophaga (Spotted Slug) Heritage Rank: G2G3, S1S3 Natural History A. Taxonomy Family: Arionidae Magnipelta mycophaga Pilsbry, 1 953 The original species description by Pilsbry (1 953, see also Pilsbry and Brunson 1 954) and placement in the Arionidae are still valid, although Webb and Russell ( 1 977) noted possible alliance with the Camaenidae, based on anatomical features. The genus is monospecific and restricted to the interior Pacific Northwest. B. Species Description Morphology: Does not closely resemble any other described North American slug (Frest and Johannes 1 995). In the original description, based on an immature specimen, Pilsbry (1 953) states the appearance of Magnipelta mycophaga as "characterized by the structure of the mantle and foot ... the mantle covering far the greater part of the upper surface. The mantle is free anteriorly for more than one-fourth of its length, smooth, chamois colored with an irregular black stripe on each side and elsewhere unevenly spotted with black. The quite short respiratory slit is slightly post-median on the right side. Length of mantle 1 6 mm. The foot is lighter colored than the mantle, spotted with black on the flanks posteriorly. It has an irregular polygonal impressed reticulation. The pedal margin is quite narrow, the pedal grooves meeting above the tail without any trace of a caudal pore. The sole is transversely wrinkled at the sides, the middle third smoother, but it is not distinctly tripartite" (p.37-38). In a second preserved and partly contracted specimen collected at a later date the mantle measured 34 mm in length, free anteriorly for 9 mm and posteriorly for 5 mm (Pilsbry and Brunson 1 954); in this specimen the slit to the pneumostome was 1 5 mm from the anterior end of the mantle. Magnipelta mycophaga can be a moderately large slug; a May sample of 12 extended animals ranged from 1 .5-6.7 cm (mean = 3.6 cm), a June sample of 20 animals from the same locality ranged from 1 .4-8.0 cm (mean = 4.3 cm) (Brunson and Kevem 1 963). Two other individuals from widely separate localities measured ca. 7.0 cm and 8.0 cm (Hendricks personal observation). Internal anatomy is described and illustrated in Pilsbry (1 953), Pilsbry and Brunson (1 954), and Webb and Russell (1977). Reproductive biology: Hermaphroditic, based on internal anatomy (Pilsbry and Brunson 1 954, Webb and Russell 1 977). There is no description of reproductive behavior and its seasonal occurrence; Pilsbry and Brunson (1 954) suggest reproduction may occur early in the year, based on finding immature animals in late May. Life span is unknown. Age/size at reproductive maturity is unknown, but Pilsbry (1 953) mentioned that the type specimen, with a mantle length 45 of 1 6 mm, was immature with a genital system only partly developed, the ducts thread-like and extremely fragile. Ecology: Found in a variety of low- to mid-elevation sites, often with water in the general vicinity. Moist, cool sites in relatively undisturbed forest with an intact duff layer, such as are found in moist valleys, ravines, and talus areas, are preferred (Frest and Johannes 1 995). Forest canopy composition at sites includes Picea engelmannii, Pseudotsuga menziesU, Pinus ponderosa, Pinus albicaulis, Larix occidentalism Abies lasiocarpa, dind Abies grandis, often with Alnus present (Appendix B; Pilsbry and Brunson 1 954, Brunson and Kevem 1 963, Hendricks personal observation); spruce-fir appears to be the most frequent forest association. The Thompson River, Sanders County location (Appendix B) is an area of near-minimal tree canopy cover, though brushy, indicating slugs may move some distance when conditions are favorable, or that the species can persist in some relatively exposed and disturbed habitats. Often found on the ground under pieces of loose bark, logs, loose stones, and in rotted wood; surface active on cool (10-1 6°C), wet and overcast days, probably most active at night. Feeds on green plant material, possibly including moss (Brunson and Kevem 1 963); the type specimen was found feeding on one of the larger fungi, hence the specific Latin name of the species (Pilsbry 1953). C. Range and Known Sites Magnipelta mycophaga is found in northwestern Montana, northern Idaho, northeastern Washington (Frest and Johannes 1 995), and probably adjacent regions of British Columbia. In Montana, this species has been documented at six localities in four counties: Flathead, Lincoln, Missoula, and Sanders (Fig. 1 0, Appendix B). Aprobable seventh Montana locality, mentioned in Pilsbry and Brunson (1 954) as in the Blackfoot Valley near Bonner, Missoula County, was too vague to be mapped and was not included in Appendix B; the Lincoln County site, centered on McGuire Creek in the Ural-Tweed Bighorn Sheep range (see Forrester 1 960, 1 962) is also poorly described in the literature, but included in Appendix B because it represents a location far removed from other reported sites. This slug species has been found at elevations between 762- 1585m (2500-5200 ft) in Montana, and up to ca. 1 829 m (6000 ft) in northeastern Washington (T. Burke personal communication). The Deer Creek, Missoula County, colony site is described by Brunson and Kevem (1 963) as about 400 m (440 yds) in length. Additional populations in northwestern Montana are likely to be discovered with additional survey effort, given that half of the known Montana sites were found since 1 998. D. Species Abundance Almost no information. In 1 954 at the Deer Creek, Missoula County site 1 9 individuals were found in May and 1 0 in June. Counts at the same locality in 1 957 were 29 April: 1 , 5 May: 1 , 10 May: 12, 1 June: 18, 7 June: 86, 23 June: 20, 20 July: 4, 4 August: 3, 5 September: 10, 22 September: 1 (Brunson and Kevem 1 963), indicating that the species may be relatively abundant in some localities. Numbers reported at other sites are 1 -2 individuals, but none of these sites have been visited more than twice, nor searched thoroughly like the Deer Creek site. 46 Apparently the Deer Creek site has not been revisited in recent decades, but the species persists (as of 2001) at the Little Park Creek site only 5.6 km (3.5 mi) to the south. Current Status A. Why Species is of Conservation Concern The Spotted Slug {Magnipelta mycophaga) is a Species of Concern in Montana because it is a regional endemic so far documented at six sites in four Montana counties, despite several decades of collecting in the region by Dr. R. B. Brunson and his students (Frest and Johannes 1 995), and limited collecting by others in recent years. Population sizes and trends are imknown. B. Threats Habitat occupied by Magnipelta mycophaga (moderate elevation mixed conifer forest, especially spruce-fir, often near water) is threatened by logging, grazing, fire, possibly rural home development, and possibly recreation and weed control. The impact of fire retardant on this and other terrestrial moUusks is not known. Little is known about this species, including sensitivity to disturbance. C. Distribution Relative to Land Allocations Documented Montana sites are on lands administered by the Cabinet Ranger District, Kootenai National Forest (1 site), Rexford Ranger District, Kootenai National Forest (1 site). Glacier View Ranger District, Flathead National Forest ( 1 site), Missoula Ranger District, Lolo National Forest (1 site). Plum Creek Timber Company (2 sites). 47 Figure 11. Distribution of Zacoleus idahoensis in Montana. • Zacoleus idahoensis ^^/Continental Divide US Forest Service 48 SPECIES: Zacoleus idahoensis (Sheathed Slug) Heritage Rank: G3G4, S2S3 Natural History A. Taxonomy Family: Arionidae Zacoleus idahoensis Pilsbry, 1903 The original species descriptions by Pilsbry (1 903, 1 948) and placement in the Arionidae are still valid. The genus is monospecific and restricted to the interior Pacific Northwest. B. Species Description Morphology: Pilsbry (1 948) states "In the field this inconspicuous slug might be mistaken for Deroceras, having a tripartite sole and postmedian pneumostome . . . , but it differs by the weakly carinate back" (p. 732). The species is black to dark brown (deep grayish olive) on the mantle and back; the sole is cream- white. The reticulation on the posterior half of the body (tail) is indistinct, predominately with longitudinal lines above and oblique on the sides. The back of the mantle is keeled, the tail strongly so. The oval mantle somewhat exceeds about one-third the length of the body; the pneumostome is present in the posterior half of the mantle margin. The foot-margin is rather narrow. There is no caudal pore, but the tail appears somewhat abruptly truncate in profile. The shell is completely buried in the mantle. Body lengths of two animals from Idaho were 1 .4 cm (mantle length 5.5 mm) and 2.3 cm (Pilsbry 1 948). Internal anatomy is described and illustrated in Pilsbry (1 948). Reproductive biology: Hermaphroditic, based on internal anatomy (Pilsbry 1 948). There is no description of reproductive behavior and its seasonal occurrence. Life span is unknown. Age/ size at reproductive maturity is unknown. Ecology: Habitat descriptions are limited. Most occurrences in Idaho are in moist microsites in relatively intact Pseudotsuga menziesii, Pinus ponderosa, and Picea engelmannii forests (Frest and Johannes 1 995) in moist valleys, ravines, and talus on both north- and south-facing slopes. Pilsbry (1 948) lists collections made in meadows and cedar swamps, white pine stands, spruce valleys, rockslides, and near springs. Populus and Alnus present at several north Idaho locations (H. Reise personal communication). Rocky substrates include sedimentary, igneous and metamorphic types; the Prospect Creek, Sanders County, Montana site (Appendix B) is described as composed of calcareous shales (Pilsbry 1 948). Herbivorous; food includes the epiphytic cryptogam Frullania (Pilsbry 1948). 49 C. Range and Known Sites Zacoleus idahoensis has so far been documented only in northern Idaho and northwestern Montana. In Montana, records exist for four widely separated sites in four counties: Granite, Lake, Lincoln, and Sanders (Fig. 1 1 , Appendix B). Three of the localities (Kootenai Falls, Wild Horse Island, Squaw Rock Campground) were discovered during surveys of moUusks on bighorn sheep ranges (Forrester 1 960, 1 962); specific collection sites provided by Forrester (1 960, 1 962) are somewhat vague. The Prospect Creek site in Sanders County was the only one known in Montana at the time of publication of Pilsbry 's monograph (Pilsbry 1 948). Reported elevations of sites inldaho range between 488- 1707 m (1600-5600 ft) (Pilsbry 1948, H. Reise personal communication), the Montana sites range between 640-1494 m (2100-4900 ft). D. Species Abundance No information, although it appears to still be present at several sites in Idaho (Frest and Johannes 1995), including as recently as 2001 (H. Reise personal communication). Pilsbry (1 948) stated it was often abundant. Montana sites have not been revisited in decades. Current Status A. Why Species is of Conservation Concern The Sheathed Slug {Zacoleus idahoensis) is a Species of Concern in Montana because it is a regional endemic so far documented at only four sites in four counties, none of which has been revisited in recent decades. Population sizes and trends are unknown, but habitat loss has occurred throughout the historic range (Frest and Johannes 1 995). B. Threats Habitat occupied by Zacoleus idahoensis (moist sites in moderate elevation mixed conifer forest) is threatened by logging, grazing, fire, trail and highway expansion, possibly rural home development, and possibly recreation and weed control. The impact of fire retardant on this species and other terrestrial moUucks is unknown. Little is known about the biology of this species, including its sensitivity to disturbance. C. Distribution Relative to Land Allocations Documented Montana sites are on lands administered by the Libby Ranger District, Kootenai National Forest (1 site), Thompson Falls Ranger District, Lolo National Forest with some private in-holdings (1 site), Philipsburg Ranger District, Beaverhead-Deerlodge National Forest (1 site), and State of Montana (1 site); the Beaverhead-Deerlodge site may be on Bureau of Land Management lands. 50 Figure 12. Distribution of Polygyrella polygyrella in Montana. • Polygyrella polygyrella ^^/Continental Divide US Forest Service 52 SPECIES ON REVIEW SNAILS SPECIES: Polygyrellapolygyrella (Humped Coin) Heritage Rank: GU,SU Natural History A. Taxonomy Family: Ammonitellidae Polygyrellapolygyrella (Bland and Cooper, 1 861) Originally described by Bland and Cooper (1 861) as Helix polygyrella, with later placement by Cooper (1 868) as Helicodiscus polygyrella. The genus is monospecific and restricted to interior Pacific Northwest. B. Species Description Morphology: Pilsbry (1 939) describes the shell as "discoidal, with wide umbilicus about one- third of the diameter; of a pale greenish yellow tint, somewhat translucent, glossy. Spire varies from nearly flat to convex, of very closely coiled whorls. Initial 2 to 3 whorls smooth, the rest with rather strong radial ribs which become obsolete near the aperture . . . Suture impressed, descending a little to the aperture. Umbilicus well-like, enlarging in the last half whorl. Aperture lunate-triangular, the peristome thickened within; parietal wall with an erect, triangular tooth connected with the ends of the lip. Within the last whorl there are one or two radial rows of three teeth each, visible through the shell" (p. 558-559). Shell diameter of 26 Idaho specimens ranged from 8.6 to 1 0.5 mm (mean = 9.7 mm), but diameter of specimens from other localities ranges to 13.0 mm. Number of whorls varies from 6.5 to 8.5. Shell height is from 40-50% of the diameter. Diameter of the type specimen, presumably from Sanders County, Montana, is 11.5 mm, height 5 mm (Bland and Cooper 1 861). Internal anatomy is illustrated and described in Pilsbry (1939). Reproductive biology: Hermaphroditic, based on internal anatomy (Pilsbry 1 939). There is no description of reproductive behavior and its seasonal occurrence. Life span is unknown. Age/ size at reproductive maturity is unknown. Ecology: Often found in moist forests of Pseudotsuga menziezn and Picea engelmannii, often in association with outcrops and talus of various rock types (Bland and Cooper 1 861 , Pilsbry 1 939, Frest and Johannes 1 995). Inhabits moss and decaying wood in dampest areas of forest cover (Bland and Cooper 1 861 , Cooper 1 868); moist valley, ravine, and talus sites are 53 preferred, apparently near water (Frest and Johannes 1 995). There is no information on food habits. Associated moUusk species include the slugs Zacoleus and Hemphillia. C. Range and Known Sites Polygyrellapolygyrella is found in northwestern Montana, northern Idaho, and the Blue Mountains of extreme southeastern Washington and extreme northeastern Oregon (Pilsbry 1 939, Frest and Johannes 1 995). The eastern slope of the Coeur d' Alene Mountains, Sanders County, Montana is considered the type locality (Pilsbry 1 939, Frest and Johannes 1 995), although the original description (Bland and Cooper 1861) places the locality only as the eastern slope of the Coeur d' Alene Mountains (later identified as Montana by Cooper 1 868), which led others to place the type locality in Idaho (Elrod 1 902, Henderson 1 93 6, Coan 1981). The type locality may actually be somewhere in Mineral County; Cooper traveled along the road constructed by Lt. John Mullen up the St. Regis River from its confluence with the Clark Fork River at St. Regis (Coan 1981), passing through Mullen Gulch. In Montana, this species is currently recognized from four sites at elevations between 792 and 1097 m (2600 and 3600 ft) in two counties: Sanders and Mineral (Fig. 12, Appendix B). However, Elrod (1902) and Pilsbry (1 939) note an unique variety oi Polygyrellapolygyrella, named montanensis, found in the "Deer Lodge Valley" sometime prior to 1 902 by Mr. Hemphill. The locality is not listed in Appendix B, but indicates that the species may also be present in Powell or Deer Lodge counties. Additional locations are possible. Requirements may be similar to Radiodiscus abietum/judging by the similarity in their distributions. D. Species Abundance No information. A few Idaho populations were still extant in the early 1 990 's (Frest and Johannes 1 995), but there is no indication that the species has been found in Montana, even at the known localities, in recent decades. Current Status A. Why Species is of Conservation Concern The Humped Coin (Polygyrellapolygyrella) is a Species on Review in Montana because it is a regional endemic of unknown status so far documented at only four (possibly five) sites in two Montana counties, despite several decades of collecting in the region by Dr. R. B. Brunson and his students. There is evidence of extirpations and population declines in other states (Frest and Johannes 1 995). Population sizes and trends in Montana are unknown, and there is no evidence that the snail has been documented in Montana in recent decades. B. Threats Logging and grazing over most of the known range are probably the greatest threats, through alteration of appropriate habitat. However, alteration of habitat from fire, highway and road 54 construction, rural home development and land clearing could represent threats, as could fire suppression retardants and chemical methods of weed control. C. Distribution Relative to Land Allocations Documented Montana sites are on lands administered by the Thompson Falls Ranger District, Lolo National Forest with private in-holdings (1 site), Superior Ranger District, Lolo National Forest (1 possibly 2 sites), and 1 site on private land near Thompson Falls. The vague locality for the Deer Lodge Valley site precludes assigning ownership to the lands where it was found. 55 Figure 13. Distribution of Radiodiscus abietum in IVIontana. • Radiodiscus abietum ^^/Continental Divide US Forest Service 56 SPECIES: Radiodiscus abietum (Fir Pinwheel) Heritage Rank: GU,SU Natural History A. Taxonomy Family: Helicodiscidae Radiodiscus abietum Baker, 1930 The original designation and placement remain valid and unchanged (Pilsbry 1 948, Frest and Johannes 1995). B. Species Description Morphology: Pilsbry (1948) describes the shell as "small (6.7 mm), subdiscoid, umbilicate, thin, but with heavy, almost opaque epidermis. Color: light chocolate-brown. Whorls: maximum 5 3/4, gradually increasing in diameter, well rounded but markedly flattened above; last slightly descending; suture deep. . . Sculpture of later whorls: growth-riblets quite low but angular and sharply defined, markedly and broadly concave below periphery . . . Umbilicus: about 6. 1 times in maj . diam. of shell; with almost vertical walls. Aperture: crescentric, slightly oblique . . ." (p. 658, 660). Shell diameter is 4.9 to 6.7 mm, shell height 2.6 to 3.2 mm, with 5.0 to 5.75 whorls (Pilsbry 1 948). Diameter of 1 5 "representative" shells from seven Montana localities ranged from 2.5 to 7.0 mm (mean = 5.1 mm); shell height ranged from 1 .4 to 4.0 mm (mean = 2.8 mm); number of whorls ranged from 3 .5 to 6.0 (Brunson and Russell 1 967). Internal anatomy is illustrated and described in Pilsbry (1 948). Reproductive biology: Hermaphroditic, based on internal anatomy (Pilsbry 1 948). There is no description of reproductive behavior and its seasonal occurrence. Life span is unknown. Age/ size at reproductive maturity is unknown, but Pilsbry (1 948) indicated the type specimen (diameter 4.9 mm, 5 whorls) was immature. Ecology: Surprisingly little detailed information is available. Most often found in moist and rocky Douglas-fir (Pseudotsuga menziesii) forest at mid-elevations in valleys and ravines (Frest and Johannes 1 995). At some Montana locations. Western Red Cedar (Thuja plicata) formed the canopy. Often this species is found in or near talus of a variety of rock types or under fallen logs (Pilsbry 1948, Brunson and Russell 1967, Frest and Johannes 1995). C. Range and Known Sites Radiodiscus abietum is known from extreme northeastern Oregon, extreme northeastern and southeastern Washington, northern Idaho, and northwestern Montana (Pilsbry 1 948, Frest and Johannes 1995). In Montana, this species has been found at 13 sites in six counties: Lake, Lincoln, Mineral, Missoula, Ravalli, and Sanders (Fig. 1 3, Appendix B). All sites are west of 57 the Continental Divide (Brunson and Russell 1967) at elevations from 823 to 1707 m (2700- 5600 ft). Requirements may be similar to Polygyrellapolygyrella/judgmg by the similarity of their distributions. D. Species Abundance No information. Usually only single individuals were collected at the Montana sites (Brunson and Russell 1 967). Frest and Johannes (1 995) consider Radiodiscus abietum a species that was once common and widespread that is now much more rare. Current Status A. Why Species is of Conservation Concern The Fir Pinwheel {Radiodiscus abietum) is a Species on Review in Montana because it is a regional endemic of unknown status, so far documented at 1 3 sites in six Montana counties, despite several decades of collecting in the region by Dr. R. B. Brunson and his students. There is evidence of extirpations and population declines in other states (Frest and Johannes 1 995). Population sizes and trends in Montana are unknown, and there is no evidence that the snail has been documented in Montana in recent decades. B. Threats Logging and grazing over most of the known range are probably the greatest threats, through alteration of appropriate habitat. However, alteration of habitat from fire, highway and road construction, rural home development and land clearing could represent threats, as could fire suppression retardants and chemical methods of weed control. C. Distribution Relative to Land Allocations Documented Montana sites are on lands administered by the Confederated Salish and Kootenai Tribes (3 sites). State of Montana (1 site, but bounded closely by the Missoula Ranger District, Lolo National Forest), Superior Ranger District, Lolo National Forest (1 site). Darby Ranger District, Bitterroot National Forest (3 sites). Cabinet Ranger District, Kootenai National Forest (2 sites), Fisher River Ranger District, Kootenai National Forest (1 site), Libby Ranger District, Kootenai National Forest (1 site), and the Rexford Ranger District, Kootenai National Forest (1 site). 58 Figure 14. Distribution of Udosarx lyrata in Montana. • Udosarx lyrata ^^/Continental Divide US Forest Service 60 SLUGS SPECIES: Udosarx lyrata (Lyre Mantleslug) Heritage Rank: G?TU, SU {U. I lyrata); G7TI, SI (airusselli) Natural History A. Taxonomy Family: Arionidae Udosarx lyrata Webb, 1959 The original species determination and name (Webb 1 959) are still valid, although Udosarx lyrata is now included in the Arionidae instead of Webb's (1959) tentative placement in the Philomycidae and later placement (Russell and Webb 1 980) with the Oreohelicidae. Udosarx lyrata russelli is a subspecies recognized by Russell and Webb (1 980), however, they suggested that the subspecific designation might become useless once new material from additional localities is available for study. Because Webb's (1 959) species description did not include a subspecies name, the original material was named Udosarx lyrata lyrata by Russell and Webb (1 980). The genus is monospecific and restricted to the interior Pacific Northwest. B. Species Description Morphology: Webb (1 959) notes that the external form of Udosarx lyrata is "much as in Zacoleus, mantle more elongate, back more carinate. Respiratory pore posterior, and posterior-edge of mantle notched (as in Zacoleusy (p. 22). Udosarx differs from Zacoleus especially in the shape of the radular teeth. Webb (1 959) continues that Udosarx is about half as large as sexually mature Zacoleus. The body is "bluish gray with a lighter tawny zone on the keel of the back. Grooves on the body darker than adjoining areas; 7-8 grooves from posterior mid-dorsum to posterior-edge of respiratory pore, much as in Zacoleus. Mantle with blackish lateral lines. Mid-mantle to front-edge with black punctuations vaguely delineating a grid pattern. Right line is more sinuous than the left, and the two lateral lines for a lyre-shaped symbol — Whence the species name, lyrata. The intensity of coloration may vary" (p. 22). An alcohol-preserved specimen of Udosarx lyrata russelli measured 2.4 cm in length (Russell and Webb 1 980). For this subspecies, "the head and neck uniformly dark but not black The mantle is attached far back, so that the anteriorly a long free-lobe overlies the neck. The central area of the fore-half of the mantle bears a number (18-30) of scattered black dots and bars; unlike the holotype, the black lines of the upper sides extend forward to almost the front edge of the mantle. Otherwise the lines are as in the holotype, diverging from each other in very short arcs to give the lyre shape. The posterior mantle-edge is deeply notched . . . The respiratory pore is posterior and on the right edge of the mantle. The mantle covers somewhat 61 less than half the body, which is moderately carinate (not keeled) dorsally. The tail-tip is acutely pointed. . ." (p. 8). Internal anatomy is illustrated and described in Webb (1 959) and Russell and Webb (1 980); the latter publication also includes photographs of live animals that clearly show the lyre-pattern on the mantle. Reproductive biology: Hermaphroditic, based on internal anatomy (Webb 1959, Russell and Webb 1 980). Courtship and copulation were observed in captive animals in November (Russell and Webb 1 980). Otherwise there is no description of reproductive behavior and its seasonal occurrence. Life span is unknown. Age/size at reproductive maturity is unknown, although presumably the individual 2.4 cm in body length (Russell and Webb 1 980) was mature. Ecology: Found in moist mixed-conifer subalpine forest, preferably in moist valleys, ravines, and talus sites (Webb 1 959, Frest and Johannes 1 995). Also found in riparian areas with a canopy of Picea engelmannii, Pseudotsuga menziesn, Populus andAlnus (W. Leonard personal communication). The subspecies U. I ra^^^/// was found in south-facing open P/a2i/^ ponderosa forest with little undergrowth (Russell and Webb 1 980). At all sites, individuals were located on the undersurfaces of fallen logs or within nearly completely rotten logs, and under rocks. Animals were active in wet and cold (1 0°C [50°F]) conditions (Webb 1 959, Russell and Webb 1 980); captive animals preferred temperatures <21 °C (70°F). C. Range and Known Sites Udosarx lyrata has so far been documented only in northern Idaho and northwestern Montana (Frest and Johannes 1 995). The type locality is near Lolo Pass, but on the Idaho side (Webb 1 959). In Montana, records exist for only three sites in two counties: Missoula and Ravalli (Fig. 1 4, Appendix B). The two Missoula County sites, discovered in 1 965 and 1 966 near Potomac and Gold Creek (Russell and Webb 1 980), are far from the Ravalli County site, discovered at Bunkhouse Creek in the Bitterroot Mountains in 200 1 (W. Leonard personal communication). Reported elevations are 1067-1524 m (3500-5000 ft). Additional locations are likely to be discovered. D. Species Abundance Little information. Only one individual was found at the Ravalli County site (W. Leonard personal communication). Russell and Webb (1980) reported finding 1 7 individuals at the Potomac, Missoula County, site on 3 May 1 965, several individuals on 2 1 November 1 965, and 3 individuals on 5 May 1 966. Two individuals were found at the Gold Creek, Missoula County, site on 5 May 1 966. Russell (Russell and Webb 1 980) collected an individual at the species type locality in 1 966, almost 1 2 years after it was first found there (Webb 1 959). Known to be present at some Idaho sites in recent years (Frest and Johannes 1 995, W. Leonard personal communication). 62 Current Status A. Why Species is of Conservation Concern The Lyre Mantleslug (Usosarx lyrata) is a Species on Review in Montana because it is a regional endemic of unknown status so far documented at three sites in two Montana counties, despite several decades of collecting in the region by Dr. R. B. Brunson and his students. There is evidence of extirpations or population declines, largely inferred from loss of habitat (Frest and Johannes 1 995). Population sizes and trends in Montana are unknown, and there is no evidence that the Missoula County sites have been resurveyed in recent decades. B. Threats Habitat occupied by Udosarx lyrata (moist sites in valley and mid-elevation mixed conifer forest) is threatened by logging, grazing, fire, possibly rural home development and road construction, and possibly recreation and weed control. The impact of fire retardant and chemical means of weed control on this and other terrestrial moUusk species is unknown. Little is known about the biology of this species, including its sensitivity to disturbance. C. Distribution Relative to Land Allocations Documented Montana sites are on lands administered by the Darby Ranger District, Bitterroot National Forest (1 site). Plum Creek Timber Company (1 site), and private ownership (1 site). The type locality in Idaho is 4 km (2.5 mi) from land in Montana administered by the Missoula Ranger District, Lolo National Forest and Plum Creek Timber Company. 63 Bibliography of Montana Terrestrial MoUusks of Special Concern Bartsch, P. 1916. Two new land shells from the western states. Proceedings of the United States National Museum 51:331-333. Beetle, D.E. 1957. The moUusca of Teton County, Wyoming. The Nautilus 71:12-22. Beetle,D.E. 1961. MoUusca of the Big Horn Mountains. The Nautilus 74:95-102. Beetle, D.E. 1989. Checklist ofrecent moUusca of Wyoming, USA. Great Basin NaturaUst 49: 637- 645. Beetle, D.E. 1997. Recolonization of burned aspen groves by land snails. Yellowstone Science 5(summer):6-8. Berry, S.S. 1913. A list ofmoUusca from the MusselsheU Valley, Montana. The Nautilus 26:130-131. Berry, S.S. 1916. Notes on moUusca of central Montana. The Nautilus 29: 124-128. Berry, S.S. 1919. MoUusca ofGlacier National Park. Proceedings ofthe Academy of Natural Sciences of Philadelphia 71 : 1 95-205. Berry, S.S. 1 955. An important new land snail from the Mission Range, Montana. Bulletin ofthe Southern California Academy of Sciences 54:17-19. Bland, T, and J. G. Cooper. 1 861 . Notice of land and freshwater shells collected by Dr. J. G. Cooper in the Rocky Mountains, etc., in 1 860. Annals ofthe Lyceum of Natural History of New York 7:362-370. Boag, D. A., and W. D. Wishart. 1 982. Distribution and abundance of terrestrial gastropods on a winter range of bighorn sheep in southwestern Alberta. Canadian Journal of Zoology 60:2633- 2640. Brunson,R.B. 1956. The mystery of Discus brunsoni. The Nautilus 70:16-21. Brunson, R. B., and N. Kevern. 1 963 . Observations of a colony of Magnipelta. The Nautilus 77:23- 27. Brunson, R.B., and U. Osher. 1957. Haplotrema from wQstemMontSimi. The Nautilus 70:121-123. Brunson, R. B., and R. H. Russell. 1 967. Radiodiscus, new to moUuscan fauna of Montana. The Nautilus 81:18-22. 64 Carlson, J. 2003. MontanaAnimal Species of Concern. Montana Natural Heritage Program and Montana Fish, Wildlife and Parks, Helena, Montana. 1 4 pp. Coan, E. 1981. James Graham Cooper, pioneer western naturalist. University Press of Idaho, Moscow, ID. 255 pp. Cooper, J. G. 1868. The shells of Montana. American Naturahst 2:486-487. Elrod,M.J. 1901a. Montana shells. Rocky Mountain Magazine 2:691-697. Elrod,M. J. 1901b. Limnological investigations at Flathead Lake, Montana, and vicinity, July, 1899. Transactions of the American Microscopical Society 22:63-80. Elrod,M.J. 1901-1902. Collecting shells in Montana. The Nautilus 15:86-89, 103-104, 110-112, 129-130. Elrod, M. J. 1 902. Abiological reconnoissance in the vicinity of Flathead Lake. University of Montana Bulletin No. 10, Biological Series No. 3. Elrod, M.J. 1903a. l