Meeting Abstract
Most empirical studies have used interspecific comparisons to assess vulnerability to environmental/climate change. However, intraspecific variation is the source of evolution and population or species differences in variation can result in different responses to such changes. In this study, we test how altitudinal gradients affect variation of thermal and hydric traits – both strongly associated with the evolutionary history – in amphibians. We compared mean thermal and hydric traits across different altitudes within-species in five anuran species. We sampled specimens from two mountain ranges at the Brazil’s Atlantic Rainforest, from sea level to 1600 m, and measured thermal tolerance (critical thermal maximum, CTmax, and minimum, CTmin) and water balance (rates of evaporative water loss, EWL, and water uptake, WU). We hypothesized that populations from highlands would show lower CTmin, CTmax, EWL and higher WU, as well as higher thermal tolerance range (i.e., thermal fundamental niche, TFN) and warming tolerance (WT, i.e. the difference between CTMax and the maximum temperature of the environment). Effect of altitude was stronger in thermal traits compared to hydric ones. For most species, we confirmed our expectations for CTmin, CTmax, WT and TFN, however EWL or WU showed no difference along the elevational gradient. Taken together, our results indicate that species respond in different degrees to environmental/climate change and, therefore, assessment of vulnerability can be biased depending on which population is measured. This has implications on predictability of climate change impact on species, and deserves further consideration.
