Background/Question/Methods: Climate change is a current and increasing threat to global biodiversity. In response to climate change, animals may exhibit stress responses that can negatively impact their fitness and survival. Predicting such stress responses is therefore critical to informing actionable conservation management strategies. Plethodontid salamanders are a group of terrestrial amphibians that are particularly sensitive to changes in climate, as their lungless anatomy requires them to live in cool, moist habitats that allow for cutaneous respiration. Across montane habitats, terrestrial plethodontids vary in abundance across temperature and moisture gradients. Predicted climate shifts towards hotter and drier environments is likely to differentially impact the stress responses of individuals occupying different parts of the landscape. Using a novel technique to measure the stress hormone corticosterone through dermal secretions, we experimentally exposed salamanders from four landscape-types (hot/dry; hot/wet; cool/dry; cool/wet) to climactically stressful conditions including (1) increased temperature, (2) decreased humidity, and (3) increased temperature and decreased humidity.
Results/Conclusions:
We found no difference between the landscape-origin or the interaction of landscape-origin and experimental treatment, but we saw a significant increase in corticosterone pre- and post-exposure in all treatments. Salamanders from all origins that were exposed to the hot and dry treatment had the greatest increase of stress post-exposure relative to the other two treatments. Our results suggest that salamanders may be able to tolerate the effects of either temperature or humidity changes, but mount stronger stress responses when exposed to combined hot and dry conditions. Our findings highlight the importance of including multiple climactic conditions in wildlife stress responses in the face of climate change.