Climate change models of biodiversity loss are underestimating future extinctions, because as animals move around they compete and parasitize each other. Already animals and plants that can’t handle increasing temperatures are moving to cooler places.
Some can’t move fast enough to get to better places before they die-off, and those that do make it may be out-competed by species already there or other species that moved faster and got there first.
Animals with small territories, specialized adaptations that can’t move to cooler places are the most likely to go extinct as well as be out-competed by species that can tolerate a wider range of habitats.
Urban et al speculate that current predictions of biodiversity loss under climate change — many of which are used by conservation organizations and governments — could be vastly underestimating species extinctions.
M. C. Urban, J. J. Tewksbury, K. S. Sheldon. On a collision course: competition and dispersal differences create no-analogue communities and cause extinctions during climate change. Proceedings of the Royal Society B: Biological Sciences, 2012; DOI: 10.1098/rspb.2011.2367