Meeting Abstract

36.4  Tuesday, Jan. 5  Climate change increases the likelihood of catastrophic avian mortality events during extreme heat waves WOLF, BO*; MCKECHNIE, AE; Univ. of New Mexico, Albuquerque; Univ. of Pretoria, Pretoria wolf@unm.edu

Predicting how human-induced climate change will affect animal distribution, abundance and diversity requires an understanding of the mechanisms underlying both the direct and indirect effects. Although little studied, among the most important direct effects may be catastrophic mortality associated with extreme heat and drought. Climate models predict an increase in both the frequency and severity of these extreme climate events, and historical records demonstrate the potential for catastrophic mortality. Here we quantify the functional mechanisms underlying avian mortality associated with heat stress and the lack of water. We develop a physiological model that predicts rates of evaporative water loss and survival times as a function of body mass and dehydration tolerance. Current and historical accounts already document catastrophic mortality caused by hyperthermia or through dehydration. Our projections suggest that increasing global temperatures, combined with increased frequency and intensity of heat waves and drought, will result in more frequent catastrophic mortality, and could depopulate regional bird communities.