Professor Oregon State University Corvallis, Oregon, United States
Abstract: The cascade torrent salamander (Rhyacotriton cascadae) belongs to a monogenetic family endemic to the Pacific Northwest. A headwater obligate, the cold and fast flowing streams in the western slopes of the Cascade mountain range that the species lives in are predicted to be substantially impacted by the effects of climate change. In recognition of projected declines in habitat, the species is one of two Rhyacotritonidae species currently being considered for listing under the Federal Endangered Species Act (ESA). Successful conservation efforts rely on understanding how genetically distinct populations are delineated on the landscape. However, only one study (Good et al., 1987) has examined the genetic structure of the species. In order to inform future conservation efforts, we took samples from 144 individuals at 27 sites spread out across the spatial extent of the species range. Using a genotype by sequencing (GBS) approach, we set out to identify distinct populations, and spatial patterns of genetic diversity. We uncovered previously unknown population structure within R. cascadae, as well as evidence of localized adaptation. Our work identifies unique populations of this ESA candidate species, and highlights the ability of GBS data to uncover fine scale population differentiation, as well as adaptive capacities.
