File Geodatabase Feature Class
Tags
Freshwater mussels, Anodonta californiensis, Magaritifera falcate, Gonidea angulata, biota, environment, inlandWaters, California, Lake Del Valle, Suisun Marsh, W.F. Walker River, M.F. Tuolumne River, Truckee River, Donner Lake, Susan River, Scott River, Klamath River, Shasta River, S.F. Eel River, Russian River, Lost River, Tule Lake, Spanish Creek, M.F. Feather River, S.F. American River, Clear Lake, Napa River, Sacramento River, Dye Creek, McCloud River, Pit River, S.F. Pit River, Big Lake, Fall River, Tule River, Hat Creek, San Antonio Creek, N.F. Stanislaus River, N.F. Tuolumne River, S.F. Tuolumne River, San Joaquin River, Pajaro River
The purpose of this project was to develop a strategic survey design and to resurvey historical sampling sites (pre-1995) for the freshwater mussel Anodonta californiensis (Figure 1a), a Forest Service Region 5 sensitive aquatic bivalve mollusk. Although two other species belonging to different genera, namely the western pearlshell Magaritifera falcata (Gould, 1850) (Family Margaritiferidae, Figure 1b), and western ridge mussel Gonidea angulata (Lea, 1838) (Family Unionidae, Figure 1b), currently have no federal status, there is a concern that their populations and distributions may be declining (Taylor 1981, Frest and Johannes 1995, Mock et al. 2004, Howard 2008). Therefore, surveys were conducted for these two species also to better define their status as a basis for evaluating whether they warrant any protections. All of these species may co-occur, so a survey targeting the regionally sensitive Anodonta californiensis, was effective in detecting whether the other two species were present.
Freshwater mussels are one of the most imperiled groups of organisms on the planet (Williams et al.1993, Strayer et al.2004, Strayer 2006, REgnier et al.2009). Although western freshwater mussels have been declining as well (Taylor 1981, Hovingh 2004), recent surveys have not generally been conducted disallowing any clear indication of current compared to historic distribution and abundance. The California floater mussel, Anodonta californiensis Lea 1852 (Family Unionidae) was designated by the Forest Service as a Regionally Sensitive species in 1999. However, distributions of A. californiensis on public lands in California were poorly defined and taxonomic affinities across the western states were confused because of high genetic variability (Mock et al. 2004). This species has been a C2 candidate species for listing under the Endangered Species Act and is presently given a conservation status designation of "C3Q", meaning that globally there are probably no more than 300 populations in existence and that taxonomic problems preclude accurate assessment of actual conservation status. To address this data gap, surveys for A. californiensis and other Regionally Sensitive species have been conducted since 2001 (Brim Box et al. 2005, Howard 2008, Mock et al. 2010). Based on these earlier surveys, it became apparent that systematic surveys concentrated in specific geographic areas such as individual national forests would yield poor success in finding occupied sites (Howard 2008). Therefore during 2008-09, a strategic survey method was employed by prioritizing and revisiting locatable historic sites and water bodies to enhance chances of locating the dwindling number of extant populations ( http://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=23565 ).
Citation: - Howard, Jeanette. 2010. Sensitive Freshwater Mussel Surveys in the Pacific Southwest Region: Assessment of Conservation Status. Prepared for USDA Forest Service, 1323 Club Drive, Vallejo, California 9459-1110.
Disclaimer: The State makes no claims, promises, or guarantees about the accuracy, completeness, reliability, or adequacy of these data and expressly disclaims liability for errors and omissions in these data. No warranty of any kind, implied, expressed, or statutory, including but not limited to the warranties of non-infringement of third party rights, title, merchantability, fitness for a particular purpose, and freedom from computer virus, is given with respect to these data.
Extent
| West | -124.184978 | East | -113.747877 |
| North | 42.007351 | South | 32.728533 |
| Maximum (zoomed in) | 1:5,000 |
| Minimum (zoomed out) | 1:150,000,000 |
Disclaimer: The State makes no claims, promises, or guarantees about the accuracy, completeness, reliability, or adequacy of these data and expressly disclaims liability for errors and omissions in these data. No warranty of any kind, implied, expressed, or statutory, including but not limited to the warranties of non-infringement of third party rights, title, merchantability, fitness for a particular purpose, and freedom from computer virus, is given with respect to these data.