Range increment or range detriment?: Predicting potential changes in distribution caused by climate change for the endemic high-Andean lizard Phymaturus palluma

Abstract

An increase in temperatures and frequency of drought events are predicted in the High Andes due to climate change. Species could respond with changes in its range, abundance and phenology. Here, we used a species distribution model to assess and predict the vulnerability to climate change of the endemic lizard Phymaturus palluma of the Andes. The model is based on a study of the thermoregulatory behaviour of the species. We measured body temperature (Tb) and assessed its relationship with micro-environmental temperatures to determine the main source of heat used by lizards. We also quantified the preferred temperature (Tp) and maximum and minimum critical temperatures (CTmax and CTmin), and collected operative temperature (Te). We used Tb, Tp and Te to calculate the effectiveness of thermoregulation. We linked these physiological variables with climatic variables obtained from a set of global climate layers. The model predicts a substantial reduction in the available habitat over the species current distributional range. However, the model also predicted new potential distribution areas towards the West Andes, at higher elevations. Nevertheless, because of the species specialized habits and low dispersal capability, we suggest the likelihood of expansion to these new sites is marginal. Thus, distribution shifts are unlikely to prevent extinction in Phymaturus. Conservation strategies should be focused in the protection of the current distribution areas that remain suitable in the different future climate projections. Additional data are needed to determine the potential for phenotypic plasticity to mitigate the probable population decline in this species.