Catedra Post-Doc Regan Early just published a paper on the routes that species will follow to reach the areas that will be climatically suitable for them in the future, as climate changes. She took information on the climatic requirements of 15 amphibians in the Western USA and forecast the areas that would meet these requirements at points throughout the 21st century. When she overlaid these on each other, she found the ‘climate path’ that each species needs to follow.

A gap in the climate path of the speckled black salamander traps the species in a delining range in California.

The unsteady rate of climate change caused species to get stuck part way along their climate paths. Species moved forward while climate warmed, but retreated if climate cooled down for a period – two steps forward, one step back. It turns out that, during these periods when climate change pauses, if species can persist at the point of the climate path they have reached for 10 or 20 years they are ready to move forward when the climate starts to change again. Unless species can do this their progress is continually knocked back, so they end up with very small ranges – to the point of endangerment. Even if species can hang on to the advancing edge of the climate path, it’s not always enough to allow them to reach their future range.

This makes conservation under climate a change a little more tricky than we thought (and no one thought it was easy to start with). But the more we study the range-shift process, the better able we are to predict the challenges that climate change poses to wildlife.