113-7 Sunday, Jan. 8 09:30 - 09:45 Thermal dependence of sprint performance and critical thermal limits in ecologically distinct populations of a small ectotherm NEEL, LK*; MCBRAYER, LD; Georgia Southern University, Statesboro ; Georgia Southern University, Statesboro firstname.lastname@example.org
Ectotherms are thought to be particularly vulnerable to the effects of anthropogenic climate change as they perform many fitness related behaviors within a narrow, preferred range of temperatures. The Florida scrub lizard (Sceloporus woodi) is a ground-dwelling lizard that occupies longleaf pine and sand pine scrub habitats in the Ocala National Forest. These habitat types differ in their dominant vegetation, canopy cover, and availability of vertical perches and thus are ecologically different. Thermal opportunity is used to describe the availability of preferred temperatures within specific habitats so as to understand the thermal constraints that may influence available activity times as well as the energy and resources spent on thermoregulation in a given environment. We used biophysical models to measure the available environmental temperatures in longleaf pine and sand pine scrub populations. The variation in thermal environments was examined in the context of the thermal sensitivity of locomotor performance. Higher operative temperatures in sand pine scrub habitats were correlated with higher critical thermal limits and thermal optima in these populations. Despite the range of preferred temperatures being the same, the data suggest that the thermal physiology of this species is evolutionarily labile. Thus variation in thermal opportunity between longleaf pine and sand pine scrub stands is likely driving the observed divergence in thermal physiology among these populations.