IUCN threat status:

Least Concern (LC)

Distribution

Read full entry

Range Description

This species occurs patchily in Pacific drainages in the USA, in the States of California, Oregon, Idaho and Washington (NatureServe 2009). Taylor (1981) lists its distribution as southern Washington to northern and east-central California, and east to the Snake River, southern Idaho. In California, it occurs in the Klamath, upper Sacramento and northeastern interior drainages, and Lake Tahoe. It is possibly extinct in the Owens Valley, Inyo County (Taylor 1981).

Various subspecies exist, although they may need revision (Frest 1999, cited in NatureServe 2009): V. effusa effusa is rare and declining in the Sacremento River system, but widespread in the Willamette River in Oregon, the lower Columbia River in Washington and Oregon, the Snake River and a few tributary springs in Idaho (NatureServe 2009). V. e. dalli (the Dall Rams-horn) and diagonalis (Lined Rams-horn) are restricted to, respectively, four and five sites in the Klamath Lake system, Oregon, where they are listed as species of conservation concern (Brown et al. 2009).

Trusted

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© International Union for Conservation of Nature and Natural Resources

Source: IUCN

Belongs to 0 communities

This taxon hasn't been featured in any communities yet.

Learn more about Communities

Disclaimer

EOL content is automatically assembled from many different content providers. As a result, from time to time you may find pages on EOL that are confusing.

To request an improvement, please leave a comment on the page. Thank you!