Can Tropical Agamid Lizards Physiologically Tolerate the Altered Thermal Mosaic of Urban Microhabitats?

ABSTRACT

Urbanization and human‐induced environmental changes create unique and unprecedented thermal landscapes, and understanding species responses to these changes has emerged as an increasingly important area of research. One major challenge in studying these responses is the spatial mismatch between the small scale at which organisms experience their environment and the broader scale at which climate data are typically collected. We use infrared thermography to quantify the fine scale microclimate in urban and rural habitats used by two tropical agamid lizards, Calotes versicolor and Psammophilus dorsalis , that differ in microhabitat preference. By combining field‐based body temperatures and lab‐based measures of upper and lower critical thermal limits (CT _max , CT _min ) and preferences ( T _pref ), we assess how thermal heterogeneity of microhabitats influences the degree of thermoregulation ( k ) in these species. We find that thermal responses to urbanization are shaped by species‐specific thermal traits and patterns of microhabitat use. Rural microhabitats of P. dorsalis were warmer and more thermally heterogeneous than urban areas, whereas urban microhabitats for C. versicolor were warmer than rural areas. Between the species, individuals in urban areas did not differ markedly in substrate temperature used or degree of thermoconformity. Calotes versicolor also exhibited broader thermal tolerance and preferred temperature ranges than P. dorsalis . Collectively, our results suggest that P. dorsalis may be more susceptible to the thermal constraints imposed by human‐modified landscapes. Overall, we demonstrate the critical need to account for microclimatic conditions and species‐specific thermal traits when determining how animals respond to changes in the thermal environment expected from climate change.