Projected changes in climatic suitability for turtles by 2050 and 2070.

Chelonians are expected to be negatively impacted by climate change due to limited vagility and temperature-dependent sex determination. However, few studies have examined how freshwater turtle distributions may shift under different climate change scenarios. We used a maximum entropy approach to model the distribution of five widespread North American species (, , , , and ) under four climate change scenarios. We found that areas with suitable climatic conditions for and are expected to decline substantially during the 21st century. In contrast, the area with suitable climate for will remain essentially unchanged, while areas suitable for and are expected to substantially increase. The centroid for the distribution of four of the five species shifted northward, while the centroid for shifted slightly southward. Overall, centroids shifted at a median rate of 37.5 km per decade across all scenarios. Given the limited dispersal ability of turtles, it appears unlikely that range shifts will occur rapidly enough to keep pace with climate change during the 21st century. The ability of chelonians to modify behavioral and physiological responses in response to unfavorable conditions may allow turtles to persist for a time in areas that have become increasingly unsuitable, but this plasticity will likely only delay local extinctions.