Data from: Testing models of refugial isolation, colonization and population connectivity in two species of montane salamanders

Pleistocene glaciations have profoundly affected patterns of genetic
diversity within many species. Temperate alpine organisms likely
experienced dramatic range shifts, given that much of their habitat was
glaciated during this time. While the effects of glaciations are
relatively well understood, the spatial locations of refugia and processes
that gave rise to current patterns of diversity are less well known. We
use a microsatellite data set to test hypotheses of population
connectivity and refugial isolation in the web-toed salamanders
(Hydromantes) of the Sierra Nevada. We reject models of refugia with
subsequent expansion into either the high southern Sierra or low-elevation
Owens Valley, in favor of a simple isolation model with no migration
between current populations. We find no evidence of migration at even
moderate spatial scales using a variety of analyses in the southern
Sierra, and limited migration in the northern Sierra. These results
suggest that divergence in isolation following fragmentation is the
dominant process structuring genetic variation in these salamander
species. In the context of anthropogenic climate change and habitat
degradation, these results imply that salamanders and other low-vagility
alpine organisms are at risk of decline as they are unlikely to migrate
across large distances.