The accelerating warming in the Arctic has transformed the region into a warmer, wetter, and more diverse environment. Warming temperatures have encouraged the increasing growth of vegetation, particularly shrubs that provide beavers with bark to eat and branches to build with. Warming temperatures also mean that lakes and streams freeze solid for shorter periods of time or not at all, allowing beavers to pursue their construction projects for longer periods during the year.
Prior to the mid-1970s, residents of the Alaskan Arctic encountered few beaver ponds. In 2018, researchers using satellite imagery mapped 12,000 beaver ponds in Alaskan tundra.
Beavers are causing major changes in the streams and floodplains that many small Alaskan villages depend upon for food, water, and navigation. As the rodents transform lowland tundra ecosystems, they are eliminating food sources, deteriorating water quality, and making it difficult to navigate waterways.
The migration of beavers across the Arctic landscape is largely a result of climate change. But it is also becoming one of the factors amplifying climate change. Scientists are trying to figure out the degree of permafrost thawing that beaver dam-and-den building is causing and how fast these defrosted organic soils will degrade and release trapped carbon and methane.
Beaver dams alter the hydrology of streams by slowing the flow, storing and spreading water to create wetlands, raising the water table, and lowering the oxygen content of the water.
Climate-driven changes in species distributions affect human well-being as entire ecosystems continue to change. Shifts in animal habitat stimulated by climate change could have profound consequences across the globe.
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Beavers Are Flooding the Warming Alaskan Arctic, Threatening Fish, Water and Indigenous Traditions
Photo, posted June 12, 2018, courtesy of Peter Pearsall/USFWS via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio.
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