Shortface Lanx – State Wildlife Action Plan

Shortface Lanx

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The shell of F. nuttalli is broadly conical, having a wide oval base and a smooth eccentric (off-center) apex. Adult size varies considerably in different-sized streams, but is generally around 10 to 11 mm. The shell color is described as opaque chestnut-brown, cinnamon-red, and rich brown. The shell shape is roundly ovate (elliptical in outline), slightly broader posteriorly, high-arched, apex posterior; finely concentrically striate (appearing striped due to fine concentric growth rings), and depressed conic. The collumellar muscle scar is interrupted on the right side. F. nuttalli has a strongly anteriorly displaced apex and an incomplete mantle attachment. No individuals have been seen with white spots or lines

Overview

  • Species Common Name Shortface Lanx
  • Species Scientific Name Fisherola nuttalli

Ecoregions

    Special needs

    These freshwater snails occur in relatively large perennial rivers and streams ranging from 30-100 m (98-300 ft.) wide. Within such streams, it is most abundant in highly oxygenated environments on stable gravel to boulder substrates. This species most commonly occurs on the edges of rapids or immediately downstream from sizable rapids in areas with suitable substrate. It requires cold, unpolluted, fast-flowing, well oxygenated water in moderately large perennial streams with cobble-boulder substrate.

    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. nuttalli. Species is especially vulnerable in large river systems that have experienced widespread hydrologic and geomorphic alterations and suffer from pollution. Competition from invasive snails may also threaten this species. Increased air temperature, variability in precipitation, and intensified drought conditions from climate change may indirectly impact this species by degrading habitat by altering discharge, flow, and evaporation, leading to declines in groundwater reserves and spring flows, and increases in flash flooding.

    Conservation actions

    Maintain or restore high water quality. Manage extant sites to reduce the impacts of any practices that may adversely affect water quality; in particular, land managers should limit waste water discharge and agricultural runoff. Monitor known populations and survey suitable habitat for new populations.

    Key reference or plan

    Blackburn, M., and S. Foltz Jordan, C. Mazzacano, and T. Stone. 2020. Interagency Special Status/Sensitive Species Program (ISSSSP) Species Fact Sheet: Fisherola nuttallii. USDA Forest Service Region 6 and USDI Bureau of Land Management Oregon State Office. 25 pp.