F. modoci is a small, gill-breathing, freshwater snail. F. modoci can be distinguished by its strongly thickened scar margin and by a derived condition in which the length of the lateral tooth shaft is greater than the height of the tooth face. F. modoci is also one of only three species that have more than 20 cusps on the inner marginal teeth, whereas other Fluminicola species have 17 or fewer cusps.
Fluminicola modoci is typically considered a habitat specialist, described as a crenocole (i.e., occurring exclusively in spring environments). It prefers very cold, clear water in small to large springs with slow to swift flows. However, it has also been confirmed within spring-influenced lake habitat (i.e., Upper Klamath Lake) and slower flowing portions of spring-fed rivers, some with adjacent large spring complexes or head springs. Can be found on a range of benthic substrates such as sand, mud, fine pumice-basalt cobble, or boulders.
Limiting factors
Impaired water quality, habitat degradation and loss, and increasing fragmentation and isolation of the few remaining populations are the main threats to F. modoci. This species requires clear cool oxygenated water and thus is at risk from droughts, heat events and declining snowpacks which can effect groundwater springs. They are highly sensitive to water pollution, oxygen deficits, elevated water temperatures, and sedimentation. Threats to the species include dredging, nutrient enrichment, irrigation, human recreation, and sedimentation.
Data gaps
Assess distribution and determine range. Research habitat associations and collect life history information. Obtain current population size and trend data.
Conservation actions
Monitor existing populations and survey suitable habitat for new populations. Conduct habitat quality assessments. Protect new and existing sites from disturbance. Minimize fine sediments and pollutants entering occupied streams.
Key reference or plan
Blackburn, M., K. Hietala-Henschell, and E. Blevins. 2021. Interagency Special Status/Sensitive Species Program (ISSSSP) Species Fact Sheet: Fluminicola modoci. USDA Forest Service Region 6 and USDI Bureau of Land Management Oregon State Office. 29pp.
