Mission Creek Oregonian snail shell specimens.
The Mission Creek Oregonian's population size is low and trend is unknown. These snails are in the family Polygyridae. Snails in this family are of conservation concern because they have specialized habitat requirements. Snails do not readily disperse and populations are isolated. They are vulnerable to alteration of their habitat.
Description and Range
Physical description
The Cryptomastix species are medium to moderately large Pacific Northwest native species. The Mission Creek Oregonian is small, measuring about 0.43 inches (11 millimeters) wide by 0.2 to 0.24 inches (5 to 6 millimeters) high with about 4-1/2 whorls. The spire is low, and the shell is an amber-brown color. Small, fine ridges are visible on the shell, with some scattered hairs. A whorl is the part of the shell that is one 360-degree section of the spiral; the spire consists of all whorls except the body whorl. The shell opening has a thick, white rim, and as the snail’s scientific name implies, it has distinctive “teeth.”
Ecology and life history
The Mission Creek Oregonian has been found in rocky, brushy draws and riparian areas. It prefers dry, exposed taluses, most frequently basalt. Ground cover is limited to grasses and occasionally mosses or sparse trees. At the Joseph Canyon site, it was found at the mouth of a canyon in a rocky area that appeared to be the dry bed of an ephemeral creek. Along with other snail species, it was found under rocks where the ground was damp.
This species’ biology and ecology are poorly understood, with little or no information available on lifespan, oviposition behavior, eggs, or potential.
Reproductive biology is likely similar to other species of Cryptomastix that inhabit arid environments. It is hermaphroditic, but self-fertilization is normally avoided; it exchanges gametes with other individuals when conditions are favorable.
Mission Creek Oregonians may be partially herbivorous on green plants during certain seasons, while also feeding on microorganisms associated with decaying leaf litter, such as molds, yeasts and bacteria.
Like most land snails, this species is probably relatively sedentary and a poor disperser.
Geographic range
The Mission Creek Oregonian is found in the Snake River Canyon, Grand Ronde Canyon, and Joseph Creek Wildlife Area in Asotin County, Joseph Canyon, Wallowa County, Oregon, and in Lewis and Nez Perce Counties, Idaho.
Climate vulnerability
Sensitivity to climate change
There is no information on the sensitivity of this species to climate change.
Conservation
Conservation Threats and Actions Needed
- Fish and wildlife habitat loss or degradation
- Threat: Limestone quarrying.
- Action Needed: Development management recommendations.
- Agriculture and aquaculture side effects
- Threat: Unsustainable grazing of riparian habitat.
- Action Needed: Development management recommendations.
- Threat: Unsustainable grazing of riparian habitat.
- Action Needed: Install fencing to carefully manage or prohibit livestock access to occupied riparian areas.
This species' climate vulnerability is unknown. Climate vulnerability (PDF) is a way to assess the degree to which a habitat or species is susceptible to, and unable to cope with adverse impacts of climate change.
Resources
References
Applegarth, J. S. 1999. Management Recommendations for Cryptomastix hendersoni, the Columbia Oregonian (land snail) v.20, Section 2, in T. E. Burke, J.S. Applegarth, and T. R. Weasma. Management Recommendations for Survey and Manage Terrestrial Mollusks (v. 2). USFS and BLM.
Burke, T. E. 2013. Land Snails and Slugs of the Pacific Northwest. Oregon State University Press, Corvallis, OR. 344 pp.
Burke, T., J. Applegarth, T. Weasma, and N. Duncan. 1999. Management recommendations for Survey and Manage terrestrial mollusks, ver. 2.0. USDA Forest Service, USDI Bureau of Land Management. Available online at http://www.or.blm.gov/surveyandmanage/MR/TM23Species/m2000-003.htm
COSEWIC. 2013. COSEWIC assessment and status report on the Oregon Forestsnail Allogona townsendiana in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. xii + 87pp. (www.registrelep-sararegistry.gc.ca/default_e.cfm).
Duncan, N. 2009. Vespericola columbianus depressa. Species Fact Sheet. Interagency Special Status/Sensitive Species Program, Forest Service, Bureau of Land Management.
Edworthy, A., K. Steensma, H. Zandberg, and P. Lilley. 2012. Dispersal, home range size and habitat use of an endangered land snail, the Oregon Forestsnail (Allogona townsendiana). Canadian Journal of Zoology 90(7):875–884.
Frest, T. J., and E. J. Johannes. 1995. Interior Columbia Basin Mollusk Species of Special Concern. Final Report, Deixis Consultants, Seattle. Prepared for Interior Columbia Basin Ecosystem Management Project, Walla Walla, WA 362 pp.
Jepsen, S., Carleton, A., Foltz Jordan, S., 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. 88 pp.
Steensma, K. M. M., L. P. Lilley, and H. M. Zandberg. 2009. Life history and habitat requirements of the Oregon forestsnail, Allogona townsendiana (Mollusca, Gastropoda, Pulmonata, Polygyridae), in a British Columbia population. Invertebrate Biology 128:232–242.
USFWS. 2011. Endangered and Threatened Wildlife and Plants: 90-day finding on a petition to list 29 mollusk species as threatened or endangered with critical habitat: proposed rule. Federal Register 76 (No. 193, October 5, 2011): 61826-61853.