Phil. Trans. R. Soc. B 363, 2369–2375 (2008)
The early onset of Arctic springtime threatens to shrink populations of migratory species such as caribou, scientists say. The large herbivores time their arrival to make the most of nutritious plants available in the region, but rapidly rising temperatures mean that they are now out of sync with the plant growing season.
Eric Post of Penn State University and his research partner, who monitor the caribou that come to calve in the Kangerlussuaq region of west Greenland, investigated how rising temperatures are affecting plants that form the staple food supply of these animals. They found that a 4.63 °C rise in spring temperatures between 2002 and 2006 shifted the growing season of plants forward by 14 days. Over the same period, the number of caribou born fell fourfold. The researchers attribute the drop in juvenile caribou to the mismatch in timing between the emergence of new plants and the onset of the calving season.
The results bode ill for the reproductive success of large herbivores that migrate to the Arctic, which is warming at least twice as fast as other areas of the globe.