SPECIES FACT SHEETScientific Name: Polygyrella polygyrella Bland and J.G. Cooper, 1861Common Name(s): Humped coinPhylum: MolluscaClass: GastropodaOrder: StylommatophoraFamily: Megomphicidae

Synonyms: Helix polygyrella (Bland and J.G. Cooper 1861; Dodds 1917); Helicodiscus polygyrella (Hendricks 2012). Conservation Status:

Global Status: G3 (last reviewed 03 February 2006)National Status (United States): N3 (03 February 2006)State Statuses: S1 (OR); S1 (WA)(NatureServe 2018)

Federal Status (United States): Not listed (USFWS 2019)IUCN Red List: Not evaluated (IUCN 2019)Technical Description:

Adult: This taxon belongs to a genus of land snails in the family Megomphicidae. This very small family is represented in the Pacific Northwest by just two genera, Polygyrella and Megomphix. The Polygyrella genus has one species, P. polygyrella, which is distinct in the Pacific Northwest with its low and rounded, closely ribbed spire, flat apex, large umbilicus, and large parietal tooth (Burke 2013).

The shell of this species is small and tightly coiled, with about 7 to 8½ whorls in number, with a nearly flat or strongly depressed spire (Hendricks 2012). The shell is somewhat transparent and glossy, and greenish or yellowish brown in color (Hendricks 2012). Within the last whorl, behind the parietal tooth, there are two rows of three tiny radial teeth, which may not be visible without magnification.

Polygyrella polygyrella is described in Burke (2013) as follows:

Shells 9 mm to 13 mm wide. Shells yellowish-brown or darker. Spire low-rounded, but first few whorls often flattened or even sunken a little to the apex. Whorls increase slowly in width. Shell smooth basally; dorsal surface ribbed with short crescents distinct to each whorl.

1

Umbilicus large, symmetrical; aperture small, lunate with a relatively large parietal tooth; lip thickened within.

Immature: Eggs or live specimens of immature P. polygyrella have not been described.

Life History:

Adults: Terrestrial gastropods can be herbivores, predators, scavengers, or omnivores (Burke 2013). Polygyrella polygyrella is presumed to feed by scraping algae, yeast, bacteria, and diatoms from rock and wood, and may occasionally feed on plant surfaces (Duncan 2008).

Polygyrella polygyrella is likely semelparous (i.e., breeding once in its lifetime) and lives 1-2 years. This species is present all year, and mortality is the highest in the summer and winter (Frest and Johannes 1995) with population turnover probably greater than 90%. Individuals are entirely terrestrial, but seek refugia sites where the humidity level is relatively high and temperature is constant, such as deep within rock talus.

Reproduction in P. polygyrella is likely similar to that of other land snails, hermaphroditic and capable of self-fertilization. However, land snails more commonly reproduce via cross-fertilization (i.e., copulation between two individuals) (Applegarth 2000). Polygyrella polygyrella most frequently copulate between April and June (Frest and Johannes 1995). In general, a land snail will mate and lay eggs in cool, damp subsurface sites where eggs are protected from predation and desiccation (Applegarth 2000).

Immature: Land snails do not tend their eggs or young. Juvenile snails look like small adults (the innermost part of the shell develops within the egg) (Applegarth 2000). For P. polygyrella, the physical appearance and number of eggs have not been reported, although eggs and juveniles of Polygyrella have been seen from May through July (Frest and Johannes 1995).

Range, Distribution, and Abundance:

Type Locality: Eastern slope of the Coeur d’Alene Mountains, Sanders Co., MT. Hendricks (2012) says the original description is based on individuals collected on the east slope of the Coeur d’Alene Mountains, probably Mineral County, Montana, but possibly Shoshone County, Idaho.

2

Range: Polygyrella polygyrella is endemic to the Pacific Northwest and has a relatively wide distribution in northern Idaho, northwestern Montana, northeastern Oregon, and southeastern Washington (Frest and Johannes 1999). This species is known primarily from Montana and Idaho, where it has been located in the Clark Fork River drainage, the Bitterroot Range, the Coeur d’Alene Mountains, and the Clearwater, Lochsa, and Selway drainages. It has also been documented in the Blue Mountains (15 miles east of Walla Walla) in Washington and east of Milton, 2-3 miles up North Fork of Walla Walla River in Umatilla County, Oregon.

Distribution: In Oregon, P. polygyrella has historically been collected from Umatilla County. Recent attempts to relocate Oregon sites have not been successful. Terrestrial mollusk surveys conducted in 2016 on the La Grande Ranger District, Wallowa-Whitman National Forest did not detect this species (Blevins et al. 2017).

In Washington, P. polygyrella has been more recently collected from Asotin, Columbia, and Walla Walla Counties. This species was located in 2009 and 2010 in Washington’s Umatilla National Forest, along the Touchet River (Leonard 2009; Richart 2009; Jepsen et al. 2011). The 2009 site is along Forest Service Road 64, approximately 20.5 miles south of US 12 (Leonard 2009; Richart 2009). Targeted surveys in the spring of 2012 on the Umatilla National Forest and BLM Vale District did not detect this species (Jepsen et al. 2012).

BLM/Forest Service Land:

Documented: Polygyrella polygyrella has been documented on the Umatilla National Forest in Columbia County, Washington, along the Touchet River.

Suspected: Due to the close proximity of records, this species is suspected on Wallowa-Whitman National Forest (in Walla Walla County) and on BLM land in the Vale District-Washington (in Asotin County), Vale District-Oregon (Umatilla County), Prineville District (Grant County) and Spokane District (Walla Walla County).

Abundance: Abundance estimates are not available for P. polygyrella. Targeted surveys found 4 live individuals and 4 shells in September 2010 (Jepsen et al. 2011). Follow-up surveys on Umatilla National Forest (Walla Walla North Fork John Day Ranger Districts) and Vale BLM District lands in May 2012 did not result in any additional detections of P. polygyrella (Jepsen

3

et al. 2012). Surveys in Montana documented single individuals up to 35 individuals (Hendricks et al. 2007, 2008).

Habitat Associations:

Polygyrella polygyrella typically inhabits mesic mixed conifer forest, often associated with streams, seeps, and rock outcrops (i.e., basalt, schist, and limestone) (Frest and Johannes 1995; Hendricks 2012; Burke 2013). This species prefers partly open forest with a diverse understory of forbs, mosses, and deciduous shrubs (Jepsen et al. 2011). It has been observed in forests where the canopy consists of western redcedar (Thuja plicata), western hemlock (T. heterophylla), grand fir (Abies grandis), Engelmann spruce (Picea engelmannii), Douglas-fir (Pseudotsuga menziesii), subalpine fir (A. lasiocarpa), black cottonwood (Populus trichocarpa), and western white pine (Pinus monticola) and the secondary canopy includes alder (Alnus) and mountain maple (Acer spicatum) (Hendricks et al. 2007, 2008; Hendricks 2012). In Washington, this species has been found along the Touchet River in the Umatilla National Forest in streamside debris, in a forest of grand fir (A. grandis), Douglas-fir (P. menziesii), and Sitka spruce (P. sitchensis) (Leonard 2009; Richart 2009).

Moist sites are preferred, low on slope or near persistent water sources, but outside of floodplains. This species is often found in leaf litter, under woody debris and rocks in damp soil and humus (Hendricks 2012; Burke 2013).

Polygyrella polygyrella is considered a mesophile or notophile, but can tolerate moderately xerophilic conditions in rock taluses, and low to medium altitudes typically between 1480-1640 ft. (~450-500 m) (Frest and Johannes 1995; Jepsen et al. 2011). In Montana, P. polygyrella has been found between 2570-4100 ft. (~780-1250 m) elevation; live specimens were found on ferns, in leaf litter, in bryophyte mats, and one under a >20 cm rock (Hendricks et al. 2007, 2008). Snails were found in south-facing lava slides on ferns, and in leaf litter and bryophyte mats.

Frest and Johannes (1995) described sites where P. polygyrella was observed during surveys in Idaho as follows:

Wooded slope with exposed basalt bedrock; small talus piles; moist, small seeps with willow (Salix), redosier dogwood (Cornus sericea), some common forbs, and nettle (Urtica).

4

Basalt talus and outcrops; range from open to tree-covered (deciduous); common nettles.

Shallow mossy basalt talus at base of steep bluff; partly forested, moist; common nettles, deciduous trees, raspberries.

Polygyrella polygyrella has been found with Oreohelix n. sp. 25, Allogona ptychophora ptychophora, O. waltoni, Cryptomastix mullani olneyae, O. vortex (Frest and Johannes 1995), and Anguispira kochi, Microphysula ingersolli, and Radiodiscus abietum (Jepsen et al. 2011).

Threats:

Terrestrial mollusks are sensitive to any actions that result in ground disturbance or alter the plant community. In particular, this includes actions that alter temperature or humidity, cause soil compaction, or lead to loss of debris and rock microsites. Roads can be barriers to dispersal, and fire, especially prescribed burning, may reduce abundance and species richness of terrestrial mollusk populations (Foltz Jordan and Hoffman Black 2012).

Since P. polygyrella can be found in mesic to semi-xeric habitats (Frest and Johannes 1999), any activities that disturb the terrain structure, overstory, plant community, litter composition/abundance, or moisture levels pose threats to this species. Intense logging and grazing in particular pose threats to P. polygyrella (Frest and Johannes 1995). The Oregon site in Umatilla County has been heavily grazed, and most of the surrounding area has been logged. No recent collections have been made at this site.

Conservation Considerations:

Research: Additional research of the species at the historic and recent collection sites is recommended to determine population status and further identify habitat requirements. Research exploring the life history of P. polygyrella could aid in identifying limiting factors and develop specific habitat management guidelines. Research into population fluctuations may improve understanding of extinction risk for this species.

Inventory: Surveys for this species are recommended to determine its current status. Future surveys for P. polygyrella are recommended on the Wallowa-Whitman National Forest during the fall (Blevins et al. 2017). Surveys could occur at suitable habitats (e.g., talus slopes, basalt outcrops, and/or seeps) along the North Fork Umatilla River, the North Fork John Day

5

River, the Wenaha River, and Joseph Creek (Jepsen et al. 2012). In Washington, this species is currently known from small numbers at few sites, and better knowledge of the population status at documented and potential sites is critical in evaluating this species’ overall status and management needs in the state.

Management: Manage potential and known sites to maintain the current vegetative cover and hydrologic regime and reduce impacts of logging and other activities. Restrict grazing and new road construction at known sites to minimize impacts to talus habitat and effects to hydrologic patterns.

At known sites, minimize disturbance of the forest floor litter, duff, and woody debris to maintain important cover and microhabitats. Conserve the naturally occurring diversity of plant species associated with this mollusk, especially in grand fir, Douglas-fir, and Sitka spruce forests. Avoid prescribed burns within key habitat areas where this species occurs or is suspected; if wildfire prevention by fuels management is required, consider planning prescribed burns in adjacent areas to protect occupied habitat. Management for this and other terrestrial snails should aim to protect and improve existing habitat conditions, where appropriate. Forest management activities and general recommendations to protect terrestrial mollusks are reviewed in detail in Foltz Jordan and Hoffman Black (2012).

Version 2: Prepared by: Katie Hietala-HenschellThe Xerces Society for Invertebrate ConservationDate: May 2019

Reviewed by: Candace Fallon The Xerces Society for Invertebrate ConservationDate: June 2019

Version 1: Prepared by: Nancy Duncan Bureau of Land Management Date: April 2008

Reviewed by: Rob Huff and Sarah Foltz Jordan Forest Service Region 6 and BLM Oregon/WashingtonThe Xerces Society for Invertebrate ConservationDate: January 2010

6

Recommended citation:

Hietala-Henschell, K., N. Duncan, R. Huff, and S. Foltz Jordan. 2019. Interagency Special Status/Sensitive Species Program (ISSSSP) Species Fact Sheet: Polygyrella polygyrella. USDA Forest Service Region 6 and USDI Bureau of Land Management Oregon State Office. 18 pp. Available at: https://www.fs.fed.us/r6/sfpnw/issssp/species-index/fauna-invertebrates.shtml       

ATTACHMENTS:

(1)References (2)List of pertinent or knowledgeable contacts (3)Map of known records in Oregon and Washington(4)Photographs of this species(5)Survey protocol, including specifics for this species

ATTACHMENT 1: References

Applegarth, J.S. 2000. Management recommendations for terrestrial mollusk species Megomphix hemphilli, the Oregon Megomphix.

Bland and J.G. Cooper. 1861. Annual Lyc. Natural History, New York. Vol 7:365.

Blevins, E., T. Burke, E. Pelton, and L. Rost. 2017. Spring 2016 Wallowa-Whitman National Forest, La Grande District terrestrial mollusk surveys. Final report to the Interagency Special Status/Sensitive Species Program (ISSSSP) from the Xerces Society. 56 pp.

Burke, T.E. 2013. Land snails and slugs of the Pacific Northwest. Oregon State University Press. Corvallis, OR 97331-4501.

Dodds, G.S. 1917. University of Colorado Bulletin. The University of Colorado Studies. Boulder, Colorado. 17(1): 1-223.

Foltz Jordan, S. and S. Hoffman Black. 2012. Effects of Forest Land Management on Terrestrial Mollusks: A Literature Review. The Xerces Society for Invertebrate Conservation under an Agreement with the Interagency Special Status and Sensitive Species Program USDA Forest Service, Region 6 and USDI Oregon/Washington Bureau of Land Management.

7

Frest, T.J. and E.J. Johannes. 1995. Land Snail Survey of the Lower Salmon River Drainage, Idaho. Prepared for USDI Bureau of Land Management, Boise Idaho. Contract # D910C30061.

Frest, T.J. and E.J. Johannes. 1999. Mollusk survey of southwestern Oregon, with emphasis on the Rogue and Umpqua River drainages. Prepared for Oregon Natural Heritage Program, Portland, OR. 414 pp.

Hendricks, P. 2005. Surveys for Animal Species of Concern in Northwestern Montana. Prepared for Montana Department of Fish, Wildlife and Parks State Wildlife Grants Program Helena, Montana.

Hendricks, P., B.A. Maxell, S. Lenard, and C. Currier. 2007. Land mollusk surveys on USFS Northern Region Lands: 2006. Montana Natural Heritage Program. Prepared for: USDA Forest Service Northern Region. 88 pp.

Hendricks, P., B. Maxell, S. Lenard, and C. Currier. 2008. Surveys and predicted distribution models for land mollusks on USFS Northern Region Lands: 2007. Montana Natural Heritage Program. Prepared for: USDA Forest Service, Northern Region. 59 pp.

Hendricks, P. 2012. A guide to the land snails and slugs of Montana. Montana Natural Heritage Program. Prepared for U.S. Forest Service – Region 1. February 2012. 214 pp.

Pilsbry, H.A. 1939. Land Mollusca of North America (North of Mexico), Vol. I, Part 1, p. 558.

[ITIS] Integrated Taxonomic Information System. 2019. ITIS Report: Polygyrella polygyrella (Bland and J.G. Cooper, 1861) TSN 77426. Accessed: 26 March 2019. Available at: http://www.itis.gov

[IUCN] International Union for Conservation of Nature. 2019. The IUCN Red List of Threatened Species. Version 2018-2. Accessed: 26 March 2019. Available at: http://www.iucnredlist.org

Jepsen, S. T. Burke, and S.F. Jordan. 2011. Final report to the Interagency Special Status/Sensitive Species Program regarding surveys for four terrestrial mollusk species on the Umatilla National Forest and Vale District BLM lands. Report submitted to Kelli Van Norman, Interagency Special Status/Sensitive Species Program. Assistance agreement L08AC13768, Modification 4. 25 pp.

8

Jepsen, S., A. Carleton, S. Foltz Jordan, and T. Burke. 2012. Spring 2012 Blue Mountains terrestrial mollusk surveys. Final report to the Interagency Special Status/Sensitive Species Program (ISSSSP) from The Xerces Society for Invertebrate Conservation. Assistance agreement L08AC137668. 88 pp.

Leonard, W. 2009. Personal communication with William Leonard. Sarah Foltz Jordan, the Xerces Society. 2009. NatureServe. 2018. Polygyrella polygyrella (Bland and J.G. Cooper, 1861). Version 7.1 (2 February 2009) Data last updated March 2018. Accessed: 26 March 2019. Available at: http://explorer.natureserve.org/index.htm

[ODFW] Oregon Department of Fish and Wildlife. 2019. The Oregon Conservation Strategy: Great Basin Ramshorn [online resource]. Accessed 26 March 2019. Available at: http://www.oregonconservationstrategy.org/strategy-species/great-basin-ramshorn/

[ORBIC] Oregon Biodiversity Information Center. 2016. Rare, threatened and endangered species of Oregon. Institute for Natural Resources, Portland State University, Portland, Oregon. 130pp.

Richart, C. 2009. Personal communication with Casey Richart. Sarah Foltz Jordan, the Xerces Society. 2009. [USFWS] United States Fish and Wildlife Service. 2019. Environmental Conservation Online System (ECOS). Online database. Available at: https://ecos.fws.gov/ecp0/reports/ad-hoc-species-report-input

Map references:

[ANSP] The Academy of Natural Sciences. 2019. Malacology Collection. Online Database. Accessed April 2019. Available at: http://clade.ansp.org/malacology/collections/index.html

[BLM] Bureau of Land Management. 2018. GeoBOB GIS export provided to Candace Fallon, the Xerces Society, by Chelsea Waddell, BLM Regional GeoBOB and ARIMS Data Coordinator, September 2018.

[GBIF] Global Biodiversity Information Facility. 2019. GBIF secretariat 2017. GBIF Backbone Taxonomy. Checklist dataset. Available at: http://www.gbif.org/species

9

[USFS] United States Forest Service. 2018. NRIS species occurrence data. Data export provided by Carol Hughes, USFS, to Candace Fallon, the Xerces Society, September 2018.

[WMSDB] Worldwide Mollusc Species Data Base. 2019. Online database. Accessed March 2019. Available at: http://www.bagniliggia.it/WMSD/HtmSpecies/4120100000.htm

Xerces Society. 2019. Species occurrence database. Queried March 2019.

ATTACHMENT 2: List of pertinent, knowledgeable contacts

Tom Burke, Private Consultant, Ellensburg, Washington

Ed Johannes, Deixis Consultants, Seattle-Tacoma, Washington

10

ATTACHMENT 3: Map of known Polygyrella polygyrella records in Oregon and Washington

Known records of Polygyrella polygyrella in Oregon and Washington, relative to Forest Service and BLM land.

11

ATTACHMENT 4: Photographs of this species and its habitat

Photographs of Polygyrella polygyrella from Idaho County, Idaho; scale bar = 1 cm. Images available in Burke (2013), copyright held by William P. Leonard, used with permission.

Photographs of Polygyrella polygyrella from the Touchet River, Umatilla National Forest. Images available in Jepsen et al. 2011, photo by Sarina Jepsen and Tom Burke, used with permission.

12

Image of Polygyrella polygyrella from Umatilla National Forest, Columbia County, Washington. Images available in Burke (2013), copyright held by William P. Leonard, used with permission.

Image of Polygyrella polygyrella habitat, open forest area near an east facing talus slope on the side of the road along the Touchet River, Umatilla National Forest. Image available in Jepsen et al. 2011, photo by Sarina Jepsen and Tom Burke, used with permission.

13

Terrestrial Gastropod Survey Protocol, including specifics for this speciesBy Sarah Foltz Jordan, Sarina Jepsen, Candace Fallon, Emilie Blevins, and Katie Hietala-HenschellLast updated January 2018

General Survey Protocol

Taxonomic group: Terrestrial Gastropoda

Please refer to the following documents for detailed mollusk survey methodology:

1. General collection and vouchering methods for aquatic and terrestrial mollusks:

See documents under the heading “Invertebrates – Mollusks” on the Interagency Sensitive and Special Status Species web page: https://www.fs.fed.us/r6/sfpnw/issssp/inventories/identification.shtml

2. Pre-disturbance surveys for terrestrial mollusk species, the objective of which is to establish whether a specific mollusk is present in proposed project areas with a reasonable level of confidence, and to document known sites discovered during surveys:

Duncan, N., T. Burke, S. Dowlan, and P. Hohenlohe. 2003. Survey protocol for survey and manage terrestrial mollusk species from the Northwest Forest Plan. Version 3.0. U.S. Department of Interior, Bureau of Land Management, Oregon/Washington and U.S. Department of Agriculture, Forest Service, Region 6, U.S. Fish and Wildlife Service. 70 pp. Available at: http://www.blm.gov/or/plans/surveyandmanage/files/11-mollusks_v3_enclosed2.pdf

3. Inventory information for terrestrial mollusk site surveys:

Inventory and Monitoring protocol page, with NRIS/GeoBOB field forms. Available at: http://www.fs.fed.us/r6/sfpnw/issssp/inventories/monitoring.shtml

ID services page, with current versions of field tags. Available at: http://www.fs.fed.us/r6/sfpnw/issssp/inventories/identification.shtml

Species-specific Survey Details: Polygyrella polygyrella

14

How: Hand collection in the appropriate habitat is the recommended survey method for this species. The following survey methodology is recommended for this species:

Visit survey areas during appropriate season(s), which for this species is likely spring and fall. Seek out key habitat features known to be utilized by the target species (e.g., talus, rocky ground in moist mixed-conifer forest such as spruce-fir forest, or cedar-hemlock, grand fir, Douglas-fir forest) while driving or hiking in a selected area. Survey promising areas by looking under talus and along brushy draws. Record geographic coordinates for each site surveyed. Standardized abundance estimates for this species at new and known sites would assist future conservation efforts, since population size is important in evaluating the stability of a species at a given locality.

Between 15 and 20 minutes search time per person should be spent at each site, although the total time spent at each site may vary based on findings. If 15 to 20 minutes are spent searching for mollusks without finding additional species during that time period, surveyors may move on to a new site.

Where: Because this species has been documented on the Umatilla National Forest and is suspected to occur on Federal lands in Oregon and Washington, additional surveys on these agency lands are recommended. Future surveys could occur at suitable habitats, including: mesic or damp forest habitats, in litter and under rocks, logs, and other woody debris, talus slopes, basalt outcrops, and/or near seeps in the Blue Mountains along the North Fork Umatilla River, the North Fork John Day River, and the Wenaha River.

Surveys for P. polygyrella could also occur near known records including suitable habitat on the Wallowa-Whitman National Forest (in Walla Walla County) along Joseph Creek and on BLM land in the Vale District-Washington (in Asotin County), Vale District-Oregon (Umatilla County), and Spokane District (Walla Walla County).

When: Terrestrial mollusks of the Interior Columbia Basin are best surveyed for in the spring, from April to May following snowmelt or from September to November after the onset of rain but before the first heavy freeze (Frest and Johannes 1995). While springtime surveys are appropriate for P. polygyrella, most known records of this species are from June through September. Fall

15

surveys for P. polygyrella are recommended (Blevins et al. 2017). Duncan et al. (2003) suggests a general set of guidelines for fall surveys:

1) autumn rains have soaked the ground (i.e., generally after at least three days of moderate to heavy rains), and 2) the soil is wet to a 1" depth or morning dew or frost is present (in areas or years in which autumn rains may not occur before the ground freezes). Surveys may continue into the late fall or early winter until 1) soil temperatures fall below 0°C (32°F) and remain below 2°C (36°F) (under the canopy) for three consecutive days (i.e. when there is a constant period of three or more days of cold temperatures), or 2) the ground is frozen, or 3) snow prevents a reasonable search. Survey conditions are still within protocol if soil temperatures drop below 2°C (36°F) during the night and rise again during the day.

Likewise, spring surveys may resume:after 1) the snow has melted and the ground is thoroughly thawed and 2) the soil temperature remains above 5°C (40°F) for at least three consecutive days. A slightly higher temperature threshold is considered necessary in the spring in order to compensate for the need for animals to become active after a long dormant period and also to allow time for new hatchlings to emerge. Surveys may continue into early summer until 1) the top half-inch of soil is dry or 2) daytime air temperatures remain above 27ºC (80ºF) for three consecutive days. Surveys windows may re-open in late spring after dry periods if rainfall is sufficient to moisten the top half-inch of the duff layers.

References (Survey Protocol only):

Blevins, E., T. Burke, E. Pelton, and L. Rost. 2017. Spring 2016 Wallowa-Whitman National Forest, La Grande District terrestrial mollusk surveys. Final report to the Interagency Special Status/Sensitive Species Program (ISSSSP) from the Xerces Society. 56 pp.

Duncan, N., T. Burke, S. Dowlan, and P. Hohenlohe. 2003. Survey protocol for survey and manage terrestrial mollusk species from the Northwest Forest Plan. Version 3.0. U.S. Department of Interior, Bureau of Land Management, Oregon/Washington and U.S. Department of Agriculture, Forest Service,

16

Region 6, U.S. Fish and Wildlife Service. 70 pp. [Available on ISSSSP intranet site].

Frest, T.J. and E.J. Johannes. 1995. Interior Columbia Basin mollusk species of special concern. Final report: Interior Columbia Basin Ecosystem Management Project, Walla Walla, WA. Contract #43-0E00-4-9112. 274 pp. plus appendices.

17