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The Dalles mountainsnail has a shell that is white basally with light mottling of various pinkish or brownish streaks. It appears light caramel-brown dorsally with white streaks along the ridges of the prominent growth wrinkles, and a white leading edge about 2 mm wide at the aperture, althought the species may be variable in color. The shell shape can vary, but it is generally elongated and turreted. The spire is rather high, mostly conic and solid. The glossy though coarse sculpturing, the distinction between protoconch and teleoconch, and the coloration are distinguishing characteristics.
Dalles mountainsnails prefer talus or basalt habitat with minimal vegetation cover. Surrounding vegetation is generally sage scrub. Taluses with this taxon usually have associated springs and seeps; but this species is a moderate xerophile and does not generally occur in the seasonally wettest portions. Litter, brush, and rocks provide refugia for the species within sites.
Limiting factors
Dalles mountainsnails are endemic to the Lower Deschutes and/or Columbia Gorge. Habitat loss and degradation are major threats to this species. Quarrying of talus, development, and road construction may impact habitat. Roadside spraying can remove food sources and microhabitat features required by mountainsnails.
Data gaps
Assess distribution. Determine species-specific habitat requirements, including vegetation components that support this species in riparian or springside sites. Continue taxonomic research and determine population genetics. Collect current population status and trend data.
Conservation actions
Maintain appropriate habitat. Minimize impacts from talus mining to Dalles mountainsnail. Avoid herbicide spraying in areas of basalt talus or outcrops. Monitor known populations and survey suitable habitat for new populations.
Key reference or plan
Blevins, E., H. Andrews, R. Huff, and R. Vora. 2019. Interagency Special Status/Sensitive Species Program (ISSSSP) Species Fact Sheet: Oreohelix variabilis. USDA Forest Service Region 6 and USDI Bureau of Land Management Oregon State Office. 14 pp.
