Meeting Abstract
8.1 Sunday, Jan. 4 Implications of habitat selection and dispersal for the responses of small ectotherms to climate change SEARS, Michael W.; Southern Illinois University msears@zoology.siu.edu
During the next several decades, animals will need to adapt to rising global temperatures. Though many correlational models predict that animals will track climates over geographical space, such results hinge on the assumption that there are no barriers to dispersal that prevent animals from reaching these new habitats. This assumption is most likely violated for small terrestrial animals because of their susceptibility to small scale fluctuations in environmental temperatures. Recent modeling efforts in my lab have shown how the thermal preferences and physiological performance of individuals interact with physical characteristics of the landscape to give rise to patterns of activity for small lizards. Here, I use similar models to show how a population of eastern fence lizards (Sceloporus undulatus) in NM might respond to predicted increases in air temperature under climate change scenarios, assuming no evolution of thermal preferences or physiological capacities. With respect to physical space, as operative temperatures rise above the preferred range of temperatures for activity, suitable patches of habitat become less abundant and more isolated from one another. With respect to time, in mid-summer, warmer temperatures during midday along with earlier and later periods of daily activity, promote higher energetic expenditures without similar gains in opportunity for foraging. Further, temperatures suitable for activity begin earlier and end later during the year, creating higher annual energetic requirements. The compound stresses of habitat fragmentation and isolation along with higher energetic demands present obstacles for population persistence that aren’t directly addressed by correlational models. Further, results presented here question the robustness of predictions from models that do not examine landscape processes at scales relevant to the biology of individual organisms.
