73.6 Saturday, Jan. 5 Functional and phenotypic responses of lizards to disturbance LATTANZIO, M*; MILES, D; Ohio University; Ohio University email@example.com
Anthropogenic disturbance has been implicated as a factor in many examples of ecological divergence. The changes in resource availability as a consequence of disturbance, mediated by trophic interactions, in part guide how species respond. At the heart of this response is the individual stress response to the disturbance itself: to disperse, adapt, or die. However, plasticity is usually the first response to variation in trophic (functional) relationships. Here we use path analysis to address hypotheses regarding the functional responses of polymorphic tree lizards (Urosaurus ornatus) to disturbance (prescribed burning) over a three-year period. Changes to the environment incurred by burning mimic those predicted by recent models of climate change; yet the functional consequences of this reorganization of dominant vegetation types remain unknown. We model trophic links using stable isotope analysis of carbon and nitrogen in tissues from multiple trophic levels (i.e., primary producers, arthropod consumers, and lizards). As predicted, our study sites differ in resource distributions, with grass cover greatest in burned regions. Isotopic data suggest that arthropods integrate vegetation and other prey types consistently across years and sites irrespective of availability. Lizards instead appear to exhibit diet variation specific to burn history: inter-morph diet differences were only significant in the more-frequently burned region. These results are concomitant with other phenotypic data, supporting a potential for ecological divergence. We will extend this analysis to predict the consequences of additional shifts in climatic and prey availability for this (and potentially other) species. Overall we will provide a synergistic model that supports a link between trophic variation and ecological divergence as a viable response to anthropogenic disturbance.