Meeting Abstract

P3.137  Thursday, Jan. 6  The thermal ecology of open-habitat and forest lizards and their potential response to climate change LOGAN, Michael L; Dartmouth College michael.l.logan@dartmouth.edu

Recent studies suggest that tropical forest lizards may be more vulnerable to the effects of climate change than other ectotherms. This may, in part, be due to the potential for heat-adapted open-habitat lizard species to invade forest environments and competitively exclude forest species. These predictions, however, assume that the thermal performance breadth is similar in open-habitat and forest species, and that there is little potential for open-habitat species to compensate for rising temperatures by changing activity patterns. I examined the potential for this “invasion” scenario to play out in an anole community on the island of Cayo Menor in Honduras by quantifying the thermal sensitivity of sprinting, operative temperature distributions (T_e), field-active body temperatures (T_b), and habitat use in Anolis lemurinus (a forest species) and A. allisoni (an open-habitat species). I obtained the optimal temperature for performance (T_o) and 80% thermal performance breadth (B₈₀) for each population. Physical models were used to measure T_es. For both species, I compared T_b with T_e and T_o to calculate a modified version of the index E (“effectiveness of thermoregulation”). I predicted that A. allisoni would have a higher value for E, and thus a relatively narrow B₈₀. This narrow B₈₀ would suggest that A. allisoni has a greater physiological susceptibility to climate change and may therefore have difficulty competitively excluding A. lemurinus. Moreover, a higher value of E may indicate a greater capacity for A. allisoni to behaviorally compensate in response to climate change and thus forego a shift in habitat altogether. Using this data, I suggest a more complex set of predictions for the response of tropical lizard communities to climate change that incorporate variation in thermoregulatory capacity and thermal sensitivity among species.