Despite its reputation, the sloth apparently disperses to new habitats with relative ease.
One of the ways in which climate change impacts Earth's ecosystems is through the movement of climate zones. In order to stay in the climate zones they've adapted to, species will have to shift poleward (or, in the case of mountainous regions, upward). This trend is already apparent, occurring at an average rate of about 6 kilometers poleward per decade, or 6 meters higher in elevation.
Obviously, some species are more capable of this than others. Trees, contrary to the depictions in The Lord of the Rings
, are not terribly good at getting from place to place. They rely on the scattering of seeds and growth of new individuals to advance into a new area. Migratory species, on the other hand, already undertake tremendous journeys every year. These disparities could lead to some significant shuffling of ecosystems as fast-moving species begin catching up to and interacting with slow-moving species that they've never seen before.
The Red Queen in Through the Looking Glass
tells Alice that 'it takes all the running you can do, to keep in the same place.' The plight of species in shifting climate zones is similar. Previous research on the subject had focused on the climate zones, using the simplifying assumption that mammals would be able to move along with them. In a paper published last week, researchers from the University of Washington examined mammals in the Western Hemisphere to find out how well they'll keep up.