Predicting Species Range Shifts Under Climate Change

by Cameron Lukos

Global climate change is causing long lasting effects on all of Earth’s natural systems. A consequence of these changes is species range shifting. Accurately predicting these shifts is very difficult and many methods have been criticized. The standard bioclimate envelope models (BEMS) have been criticized as too simple because they do not incorporate biotic interactions or evolutionary adaptation. BEMs are widely used though. Kubish et al. (2013) wanted to determine the evolutionary conditions of dispersal, because local adaptation or interspecific competition may be of minor importance for predicting future shifts. They used individual-based simulations at two different temperatures as well as competing simulations. Their results show that in single-species scenarios excluding adaptation, species follow optimal habitat conditions or go extinct if their connection to the environment becomes too weak. With competitors, their results were dependent on habitat fragmentation. If a species was highly connected to its habitat, the range shifted as predicted; if a species was only moderately connected to its environment, there was a lag time, and with low connectivity to the environment, the result was extinction. Based on this work, Kubisch et al. determined that the BEMs may work well as long as habitats are well connected and there is no difficulty dispersing. Continue reading