Eco-physiological Predictors of Ectothermic Species Responce to Climate Change in a Global Biodiversity Hotspot

Abstract

As ecological conditions are transformed by a changing global climate, it is becoming increasingly essential to understand the vulnerability and response of organisms to these altered environmental circumstances. Whereas some strides have been made in understanding the effects of global climate change on endotherms, woefully little is known about ectotherms, which constitute the bulk of the diversity of species in natural ecosystems. Though ectothermic organisms can compensate for fluctuations in the thermal environment by modifying their behavior and physiology, these adjustments likely represent a tradeoff between maintaining an optimal body temperature and allocating energy to other important life history processes (i.e. foraging, anti-predator behaviors and mate-finding). While global climate change is likely to affect many aspects of a species’ life history and ecology (e.g. susceptibility to disease, food availability, etc.) some of the most direct impacts are likely to come from a possible mismatch between newly prevailing thermal conditions and the species’ thermal preferences. We investigated the thermal biology of four ecologically important reptile species in the Central Aegean Sea (Greece): Podarcis erhardii (Linnaeus 1756, Lacertidae), Laudakia stellio (Linnaeus 1758, Agamidae), Mediodactylus kotschyi (Steindachner 1870, Gekkonidae), and Hemidactylus turcicus (Linnaeus 1758, Gekkonidae). We determined the preferred body temperature for each species using a controlled thermal gradient in the lab. Combining these average thermal preferences with morphological measurements, field body temperatures, and microhabitat characteristics, our work sheds