Meeting Abstract
The use of thermal performance curves (TPC)’s to estimate lizard responses to climate warming has become common. Examining performance at varying ambient temperatures allows for comparisons of organismal performance dependent on current available temperatures and can extrapolate to predicted temperature ranges. However, integrating more than one effect of climate change on ecological and physiological performance can provide a more reasonable estimation of these responses. One such effect is limited prey abundance due either to a trophic cascade or community reorganization. In this present study, we quantified whether thermal performance curves were affected by food limitation. We experimentally limited access to food resources to one group of Urosaurus ornatus, and kept another group on a normal ration. We then estimated TPCs for each group to examine the change in temperature-dependent locomotor performance as a consequence of food availability. Our results demonstrate that whole organism performance and the preferred range of temperatures declines with limited food rations. Furthermore, the optimal temperature for performance declines as well. The heights and shapes of these curves are distinct, indicating that thermal performance is ecologically-dependent. Predictions of lizard responses to climate warming, therefore, should be placed within an appropriate ecological setting which incorporates predator-prey or other community dynamics.
