Range includes the coast ranges of California, from Mendocino County southward to Los Angeles County and disjunctly south to the Cayumaca Mountains in San Diego County; also the southern Sierra Nevada from Tulare County to Kern County (Kuchta and Tan 2006). Taricha sierrae hybridizes with T. torosa in the southern Sierra Nevada (Kaweah River area) (Kuchta 2007).
Habitat and Ecology
Breeding occurs in ponds, reservoirs, and streams, and terrestrial individuals occupy various adjacent upland habitats such as grassland, woodland, and forest (Storer 1925, Petranka 1998, Stebbins 2003, Kuchta 2005). Eggs are attached to sticks, undersides of stones, or vegetation in flowing or nonflowing water; fast-moving streams and rivers are used more often in Sierra Nevada foothills and in southern California mountains than elsewhere in the range.
This species is represented by many and/or large occurrences throughout most of the range. Total adult population size is unknown but surely exceeds 100,000. This species is common in many parts of its range. Over the long term, likely relatively stable in extent of occurrence, probably less than 25% decline in population size, area of occurrence, and number/condition of occurrences. Many historical occurrences in San Diego County appear to be extirpated. Currently relatively stable in extent of occurrence; probably relatively stable to slowly declining in population size, area of occurrence, and number/condition of occurrences.
Under natural conditions, solar UV-B radiation reduces embryo survival; effects at the population level remain to be determined (Anzalone et al. 1998).
Introduced crayfish and mosquitofish (Gambusia) prey on eggs and larvae and have caused local population declines in southern California (Gamradt and Kats 1996). Introduced fishes likely have a negative impact in some bodies of water.
Locally, population have been reduced or eliminated as a result of habitat degradation or loss caused by conversion of habitat to human uses and to a much lesser degree by large-scale commercial exploitation (Jennings and Hayes 1994). Increased stream sedimentation resulting from erosion caused by human activities and wildlfires (Gamradt and Kats 1997, Kerby and Kats 1998) has degraded breeding habitat in some areas (Jennings and Hayes 1994).
Many are killed on roads as they move between uplands and aquatic breeding sites.
None needed. Many occurrences are in protected areas.
Red List Status
Least Concern (LC)
Listed as Least Concern in view of its wide distribution, tolerance of a broad range of habitats, presumed large population, and because it is unlikely to be declining fast enough to qualify for listing in a more threatened category.
Taricha sierrae formerly was recognized as a subspecies of Taricha torosa.
Phylogenetic analysis of mtDNA data (Tan and Wake 1995) revealed the following clusters in T. torosa: (1) northern Sierra Nevada (Shasta to Nevada counties); (2) central Sierra Nevada (El Dorado to Fresno counties); (3) southern Sierra Nevada (Tulare to Kern counties) (independently derived relative to 1 and 2, above); (4) southern coastal California (San Diego and Orange counties); (5) central coastal California (Los Angeles to central and northern California). This study and additional allozyme data (Kuchta and Tan 2006) provided the basis for a phylogeographical history of T. torosa. Among other things, the data are consistent in indicating that populations in the southern Sierra Nevada are more closely related to T. torosa torosa than to T. t. sierrae.
In the interests of taxonomic stability, Kuchta and Tan (2006) refrained from advocating changes in the taxonomic status of Taricha torosa torosa and Taricha torosa sierrae, pending completion and publication of ongoing studies.
Kuchta (2007) examined genetic and morphological variation in Taricha torosa and concluded that T. torosa and T. sierrae are distinct evolutionary lineages that should be recognized as distinct species.
Geoffrey Hammerson 2008. Taricha torosa. The IUCN Red List of Threatened Species 2008: e.T59471A11946313. http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T59471A11946313.en .Downloaded on 17 November 2018