Can tadpoles take the Heat?. Comparative Thermal Tolerances in subtropical and temperate amphibian communities under global warming

DUARTE, H.; TEJEDO, M; KATZENBERGER, M; MARANGONI, F.; BALDO, D.; BELTRAN, J. F.; MARTI, D.; RICHTER-BOIX, A.; GONZALEZ-VOYER, A.

Sevilla

Congreso; XI Congreso Luso – Español de Herpetología / XV Congreso Español de Herpetología; 2010

Asociación Herpetológica Española

Some of the main challenges of forecasting the consequences of global warming are to know when, where and with what magnitude its impacts will be on biodiversity. Amphibians are the most threatened vertebrates, mainly due to habitat loss and diseases. Here we propose peak heating as an additional factor promoting their decline in the near future. Tropical amphibians are predicted to be more susceptible to local extinctions since their upper thermal limits (CTmax) are closer to environmental maxima (Tmax). We examine this prediction in 47 larval amphibian species from two distinct subtropical communities from northern Argentina differing in their maximum environmental temperature: the subtropical warm, open forest community of the Gran Chaco, the subtropical cooler community of Atlantic Forest; and a temperate community from Europe. Phylogenetically corrected results indicate first, that CTmax in amphibian larvae have evolved in response to prevailing maximum environmental temperatures, although these limits in temperate species scale with a slower rate than subtropical species. The highest physiological thermal limits are for the warm-adapted species of the Gran Chaco, and lower for species from both cooler Atlantic forest and temperate communities. Second, most species from the Gran Chaco are very prone to local extinction by expected further increases in pond temperatures since Tmax may exceed their CTmax. On the other hand, the canopy protected Atlantic forest and the temperate species are relatively safe, except for low tolerant late breeders that may be exposed to heat stress in coming years.