Migrating beavers change the landscape of the Arctic

The Arctic Report Card 2021, published by the National Oceanic and Atmospheric Administration (NOAA), reveals that beavers are slowly but steadily moving northward and expanding their range. 

Researchers from the Arctic Beaver Observation Network (A-BON) have been using satellite imagery to map the beaver’s movements northward. 

So far, more than 12,000 beaver ponds have been mapped in western Alaska. This represents a doubling of ponds in most areas over the last 20 years. 

By contrast, aerial photography in coastal areas of western Alaska from 1949 to 1955 found no beaver ponds at all. 

Beavers are ecosystem engineers, capable of changing landscapes to better suit them as well as favoring other different organisms. Almost two-thirds of the cases where surface water has increased in western Alaska were related to beaver ponds. 

Beaver ponds can melt permafrost and provide habitat to new species. The full impact of the beavers is yet to be seen. 

“The true impact of the spread of beavers into the Arctic on the environment and the Indigenous communities who live there, is not yet fully known. However, we do know that people are concerned about the impact beaver dams are having on water quality, the numbers of fish downstream of the dams, and access for their boats,” said study co-author Dr. Wheeler of Anglia Ruskin University (ARU).

“The abundance of vegetation, particularly trees and woody shrubs, appears to help beavers to thrive in previously inhospitable terrain, and we are also finding beaver lodges at ever higher elevations, including above the treeline.”

“Whether their expansion northwards is entirely due to climate change or increased populations following historical reductions in the trapping of beavers for fur and food, or a combination of the two, is not entirely clear, but we do know that beavers are having a significant impact on the ecosystems they are colonising.”

The report is available to read here Beaver Engineering: Tracking a New Disturbance in the Arctic.

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By Zach Fitzner, Earth.com Staff Writer