Meeting Abstract

P3.65  Monday, Jan. 6 15:30  Can physiological flexibility mitigate the effects of climate change in desert lizards? Part I: Thermal performance PIRTLE, E.I.; TODD, J; TRACY, CR; TRACY, CR*; Univ. of Melbourne; Univ. of Nevada Reno; Univ. of Nevada Reno; California State Univ. Fullerton ctracy@fullerton.edu

It has been hypothesized that, in the next hundred years, climate change will cause mass extinctions of reptiles because hotter thermal environments will cause detrimental effects on body-temperature-specific physiological processes and performance. It is therefore important to understand how a species might adjust its physiology to mitigate the effects of climate change and improve function in more extreme environments. The ability to perform well across a wide range of temperatures would buffer a species against detrimental effects of climate change. Similarly, populations adapted to local conditions might mitigate effects of climate change on the species, but some local populations would still be vulnerable. We used a desert iguanid, the common chuckwalla (Sauromalus ater) as a model species and measured several characteristics of performance and physiology at both a warm, low-elevation site and a cooler, high-elevation site at two points in the lizards’ active season, and found different responses to temperature between both sites and seasons. The results of our performance testing suggest there has been some population-level specialization of the common chuckwalla, where high elevation lizards are able to alter their response to temperature as the season progresses, presumably maximizing performance first in the cooler spring months and then again in the warmer summer months, while low elevation lizards show fixed traits that maximize performance at the high temperatures that they experience during the entire season. Thus, there may be sufficient variability across the species to mitigate effects of climate change, but some local populations may be vulnerable.