Assessing Site Occupancy and Microhabitat Use of the Hellbender Salamander (Cryptobranchus alleganiensis) in Tennessee

Precise monitoring of species distributions across its range and within its habitat is important for the development of effective conservation plans. Amphibian declines have been reported since the 1980s, and lack of data on distribution and habitat requirements often hinders conservation efforts. The hellbender salamander (C. alleganiensis spp.) is no exception to the trend. Although Tennessee provides areas of high-quality habitat for C. alleganiensis, standardized state-wide assessment of C. alleganiensis distribution in Tennessee has been limited to known populations and microhabitat use differences among life stages have not been well documented. I used the Maximum Entropy Algorithm to create a predictive habitat model to guide sampling efforts in Tennessee and used environmental DNA and occupancy modeling to ground truth my model and evaluate the status of the target species. I evaluated microhabitat use of larval, juvenile, and adult life stages at three streams in east Tennessee by comparing sites occupied by C. alleganiensis to random sites within each stream. Overall, my analysis suggests that available habitat for C. alleganiensis within its range in Tennessee is significantly limited, and ecoregion has a strong effect on detection probability and occupancy, with the Blue Ridge ecoregion having the greatest detection probability and occupancy rate compared to other ecoregions. Finally, my analysis indicated a strong difference in microhabitat use among life stages and identified microhabitat covariates that are potentially important for long-term C. alleganiensis conservation as means of providing guidance for stream restoration practices that may mitigate sedimentation and habitat degradation in impacted streams