Identifying Environmental Parameters To Predict Occupancy Of The Southern Appalachian Mountain Endemic, Plethodon Welleri

Plethodon welleri is a small-bodied salamander species that is endemic to select mountains in the Southern Appalachian Mountains and considered threatened across its entire range. Initial descriptions indicated that this species was a high-elevation, spruce-fir specialist only found above 1500m. However, historical and recent observations have documented populations outside of this range. The goal of this study was to assess environmental parameters correlated with occupancy by P. welleri and build a comprehensive dataset on species detection and occurrence of P. welleri. In 2022, sites were surveyed across the North Carolina and Tennessee portion of P. welleri range, and population and environmental data was collected March-November. These data have been used to model occupancy of P. welleri across three primary sampling seasons: spring, summer, and fall. The environmental factors that most strongly correlated with detection of this species were ambient temperature, humidity, soil moisture, and leaf litter depth, resulting in detection rates of 0.364 (spring), 0.430 (summer), and0.518 (fall). Terrain and elevational characteristics were important in determining site occupancy for P. welleri, with seasonal changes in elevational habitat suitability resulting in occupancy estimates of 0.603 (spring), 0.278 (summer), and 0.466 (fall). My findings indicate that the primary drivers of occupancy and detection of P. welleri have to do with the evaporative risk for this species based on environmental conditions. This study is the first to investigate the environmental covariates that influence this threatened species and will provide a framework to guide future studies and the development of effective conservation management plans.