Meeting Abstract

45.4  Saturday, Jan. 5  Modeling the costs of thermoregulation in lizards: the interplay between competition, climate and vegetation cover in Sceloporus undulatus LEVY, O*; BUCKLEY, L. B.; KEITT, T. H.; ANGILLETTA, M. J.; Arizona State University, Tempe; University of North Carolina at Chapel Hill, Chapel Hill; The University of Texas at Austin, Austin; Arizona State University, Tempe

Models of population dynamics have been used to infer the impacts of climate change on the distributions of species. The predictions of these models depend greatly on parameters that characterize the phenotype and the environment. Throughout the range of S. undulatus, behavioral thermoregulation buffers environmental extremes that would otherwise decrease performance. Under climate change, the frequency and magnitude of these extremes may increase while vegetation that provides shade may decrease. Moreover, competition during thermoregulation may entail costs that will reduce energy gain. When competing for space, individuals may be excluded from preferred thermal patches. By contrast, when competing for food, individuals may obtain less energy in preferred thermal patches. We used an individual-based model to study the outcomes of competition for shade and food in current and project climates. We also studied how changes in vegetation would affect the life-history and geographic range of S. undulatus. In the model, juveniles competed for food while adults competed for food and space. Introducing costs of competition while reducing vegetation enhances a lizard’s vulnerability to environmental extremes. Improving the realism behind individual-based thermoregulation models may increase our understanding of the complex interactions between climate, animals and vegetation cover.