Beavers are poised to invade and radically remake the Arctic
By Warren Cornwall, Science.
Excerpt: ...University of Alaska Fairbanks ecologist Ken Tape walked across the tundra on the outskirts of Nome, Alaska, to a site where a shallow stream just a few meters wide had flowed 2 years before. In its place he found an enormous pond, created by a dam made of branches bearing the distinctive marks of beaver incisors. It was a vivid illustration of how beavers are transforming the Arctic. ...Soon, the land-altering power of beavers could be felt in a region currently beyond their reach: the farthest northern parts of the Alaskan Arctic. In a 30 July paper in Environmental Research Letters, Tape and James Speed of the Norwegian University of Science and Technology forecast that as a warming climate eases Arctic temperatures, beaver populations will march northward, sweeping across Alaska’s North Slope this century. Their arrival could bring dramatic change...upending ecosystems in places such as the Arctic National Wildlife Refuge and accelerating the loss of permafrost that stores vast amounts of carbon. ...Using computer models that forecast how a warming climate could expand the amount of Alaskan tundra suitable for beavers, the researchers found that the area dotted with ponds could nearly double by 2050, and more than triple by the end of the century, from 30,000 square kilometers to 99,000 square kilometers....