Behavioral preference for microclimate conditions across elevation in Plethodon montanus.

Abstract

The ability to behaviorally regulate body conditions is critical for ectotherms, particularly in the face of global climate change when seeking stable refugia in a changing environment could facilitate survival. This is especially important for montane species that are limited to high elevations. In the Northern Gray-cheeked salamander (Plethodon montanus), studies have demonstrated that population demographics improve at higher elevations and physiological constraints may prevent them from moving into lower-elevation habitats. However, little is known about the species' ability to utilize microhabitats and behaviorally regulate by selecting preferable microclimates. Here, we used continuous position-sensing gradient chambers to examine the behavioral preference for temperature and relative humidity (RH) in P. montanus to better understand their microhabitat use and behavioral thermoregulation across an elevation gradient. We investigated the seasonal variation in both thermal and RHpreference of P. montanus collected from different elevations. Our results suggest that most recently experienced environmental temperatures influence thermal preference in animals at high elevations but not those at lower elevations. Salamanders preferred the highest available RH conditions regardless of environmental conditions or elevation. Data on shuttling behavior (movement across the behavior arena) from the experiments suggest that while salamanders shuttled a similar number of times in both types of trials, they spent significantly less time exploring when exposed to the RH gradient compared to the thermal gradient. Together these results suggest that while thermal preference is influenced by acclimation, preference for moisture conditions is less elastic.