Evidence of stronger range shift response to ongoing climate change by ectotherms and high-latitude species

A well-known response of biodiversity to ongoing climate change is range shifts towards cooler temperature areas. Still, a major gap remains in the understanding of the latitudinal component and the differences between ectotherms and endotherms in these responses. The accumulation of evidence of observed climate tracking over the years provides an opportunity to close these gaps. Here, we evaluate latitude and species' thermoregulation as explanatory variables in climate-induced range shifts. We conducted an extensive literature review, selecting empirical studies that provided information about the direction and/or magnitude of climate-induced latitudinal and altitudinal range shifts of almost 400 species. We built linear mixed models to analyze both categorical and continuous distribution data. We showed that many species consistently shifted their ranges towards the poles or higher altitudes. Most importantly, we found that the higher the latitude, the greater the latitudinal range shift, and that ectotherms show stronger range shift responses to ongoing climate change than endotherms. Our findings show that range shifts are already occurring as a result of mild global warming. As global warming intensifies, species might soon reach hard adaptation limits, where shifting ranges is no longer an option, especially for ectotherms and high-latitude species.