Meeting Abstract
One of the many changes to local environments produced by urban development is an increase in ambient temperature. This urban heat island effect is due to the replacement of vegetation with heat absorbing surfaces, such as buildings and roads, resulting in a spatially and temporally variable thermal mosaic in urban areas compared to the relatively cooler and homogeneous thermal environments of adjacent natural areas. Ectotherms, such as reptiles, are especially sensitive to the thermal environment, with body temperatures either conforming to ambient conditions, or actively regulated to achieve a preferred temperature. We studied the thermal biology of Anolis crisatellus and Anolis sagrei, two trunk-ground anoles found in the Miami metropolitan area in both natural forest fragments and highly developed urban areas. We predicted that urban areas would be warmer than natural areas, and that lizards in urban areas would have higher average body temperatures. In the field, we randomly distributed copper model lizards to measure operative temperatures, the body temperature of a non-thermoregulating lizard, and compared these to lizard body temperatures measured throughout the day. We found that urban areas have higher average temperature than natural areas, and that lizards have higher body temperatures in urban sites; in both natural and urban sites, lizards maintained higher body temperatures than operative temperatures. Because of the importance of temperature in physiological and chemical processes, as well as potential altered costs of behavioral thermoregulation, warmer urban areas have the potential to affect lizard fitness and, ultimately, natural selection.
