TORRENT IN A BOTTLE: USING ENVIRONMENTAL DNA TO DETECT COLUMBIA AND CASCADE TORRENT SALAMANDERS IN THE PACIFIC NORTHWEST
|Christopher Cousins; Oregon State University; email@example.com; Jennifer Allen, Tiffany Garcia, Dede Olson, Brooke Penaluna
Cascade (Rhyacotriton cascadae) and Columbia torrent salamanders (Rhyacotriton kezeri) are stream amphibians whose monogeneric family is endemic to the Pacific Northwest. Both species are being considered for ESA listing as their headwater stream habitat is vulnerable to habitat loss from effects of climate change. In order to provide information about current distribution and validate habitat suitability models, we performed range-wide physical surveys at 96 sites (48 sites per species: 24 in Oregon and 24 in Washington) in the spring and summer of 2019. We took eDNA samples from 12 sites per species, spread spatially across each species range. Species specific primers were developed for both R. kezeri and R. cascadae, and we used quantitative PCR (qPCR) on samples to determine if eDNA was an appropriate survey method for each species. We used Bayesian hierarchical models to determine the effects of site conditions on detectability at the site, sample, and PCR replicate levels. We observed differences in detection rates across sites, and more work is needed to determine what issues are most impactful to detectability. Our work provides a noninvasive passive sampling method for these threatened salamanders that can be used to track future occupancy shifts.