Highcap Lanx – State Wildlife Action Plan

Lanx alta are freshwater, limpet-shaped snails. They have variable (or environmentally plastic) conical shells, roughly 10-20 mm in length. They can be red, yellow, or brown in color with a complete circumferential muscle scar.

Overview

Species Common Name Highcap Lanx
Species Scientific Name Lanx alta

Ecoregions

Coast Range

Oregon's Coast Range, known for its dramatic scenery, is extremely diverse, with habitats ranging from open sandy dunes to lush forests and from tidepools to headwater streams. It follows the coastline and extends east through coastal forest to the border of the Willamette Valley and Klamath Mountains ecoregions

East Cascades

The East Cascade ecoregion extends from the Cascade Mountains' summit east to the warmer, drier high desert and down the length of the state. This ecoregion varies dramatically from its cool, moist border with the West Cascades ecoregion to its dry eastern border, where it meets sagebrush desert landscapes.

Klamath Mountains

The Klamath Mountains ecoregion covers much of southwestern Oregon, including the Klamath Mountains, Siskiyou Mountains, the interior valleys and foothills between these and the Cascade Range, and the Rogue and Umpqua river valleys. Several popular and scenic rivers run through the ecoregion, including the Umpqua, Rogue, Illinois, and Applegate rivers. Historically, this ecoregion is known …

Special needs

Lanx alta is found in large rivers and their major tributaries at low to medium elevations, spring fed lakes, limnocrene streams, and larger, slow, spring fed tributary streams. They prefer stable cobble-boulder substrate in areas with high dissolved oxygen and very high water quality.

Limiting factors

Habitat loss, including spring alteration and decreased water flow, represents a major threat to highcap lanx. Sedimentation and nutrient inputs from dredging, mining, road construction, and other land use practices may smother substrates or reduce egg survival.

Data gaps

Assess connectivity of existing populations. Determine species-specific habitat requirements. Collect current population size and trend data.

Conservation actions

Maintain appropriate water flow and quality. Maintain or restore rocky substrate. Prevent or mitigate for water diversions, dredging, or other activities that could increase sediment or nutrient levels. Monitor known populations and survey suitable habitat for new populations.

Key reference or plan

McMullen, L. and C. Fallon. 2018. Interagency Special Status/Sensitive Species Program (ISSSSP) Species Fact Sheet: Lanx alta. USDA Forest Service Region 6 and USDI Bureau of Land Management Oregon State Office. 19 pp.