SKIBIEL, A.L.*; KATS, L.B.; VANDERGON, T.L.; Juniata College, Huntingdon, PA.; Pepperdine University, Malibu, CA.; Pepperdine University, Malibu, CA.: Microsatellite allele composition differs significantly between two populations of the California newt, Taricha torosa, in the Santa Monica Mountains.

Coastal populations of the California newt, Taricha torosa appear to be in decline. Much of the coastal California newt’s home range is threatened by development and the spread of exotic invasive species. Recently, the California newt has been listed as a species of special concern by the State of California. Little is known about T. torosa population structures or the degree of isolation of populations found in adjacent watersheds along the coastal mountains. This information is essential in developing plans for conservation of this species within its dwindling home range. We assessed the degree of genetic isolation between two watershed populations of T. torosa in the Santa Monica Mountains using data from four DNA microsatellite markers. Microsatellite alleles were amplified using fluorescent labeled primers developed for microsatellite loci of Taricha granulosa. The amplified products were analyzed using an ABI 3100 Genetic Analyzer in the Genomic Analysis Technology Center at the University of Arizona. All four microsatellite loci from T. torosa were polymorphic. From a total of 25 alleles identified among the four microsatellite loci, 13 were common to both populations. Eight alleles were unique to the Trancas Canyon Creek watershed population and four alleles were unique to the Cold Creek watershed population. The significant number of unique alleles relative to shared alleles in each of these populations suggests that they may be genetically isolated.