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Satellite images show that beavers are taking over the Alaskan tundra. And transforming natural flowing waterways into ponds.

The beaver invasion is a result of climate change, but as they build their dams it is accelerating the warming process.

The rapidly warming Arctic has created a better habitat for beavers. Because the snow is melting earlier, and the permafrost is thawing there are now more shrubby plants like alder and willow that beavers consume.

As the Alaska tundra warms, these woody plants are growing along its rivers and streams, creating perfect habitats for beavers.

Aerial photography taken of the region in the 1950s showed no beaver ponds in Arctic Alaska.

 In a recent study, by an ecologist at the University of Alaska Fairbanks, Ken Tape, reviewed scanned satellite images of virtually every river, lake, and stream, in the Alaskan tundra. And he was able to count 11,377 beaver ponds.

The presence of beavers first appeared in 1980 photographs. And more and more in satellite imagery from the 2000s. And by the 2010s, the number of beaver ponds constructed doubled again.

Beavers wreak havoc on the Alaskan tundra

The Alaskan tundra has a growing beaver population. And the permafrost layers of soil that once stayed frozen year-round, are thawing. Permafrost covers about one-quarter of the northern hemisphere, including nearly 85% of Alaska.

As temperatures rise, the permafrost thaws. And the greenhouse gases carbon dioxide and methane are being released into the atmosphere.

The beaver chews up and carries wood to build dams. And the dams clog rapidly flowing rivers and streams and turn them into lush ponds.

"There's not even a lot of other animals that leave a footprint you can see from space. There is one, and they're called humans. The funny thing is that humans could not get a permit to do what beavers are now doing in this state," Tape said.

“Beavers really alter ecosystems,” says Thomas Jung, senior wildlife biologist for Canada’s Yukon government.

 The ponds they create, increase biodiversity but may also play a role in accelerating climate change.

A-BON Network studies continue

According to the Arctic Beaver Observation Network (A-BON):

“Beavers are remarkable animals that engineer the landscape by building dams and transforming linear streams into a series of ponds. The impact of this engineering on lowland ecosystems is widely recognized in temperate regions. But beavers are now moving from the forest into arctic tundra regions, where their extent and impacts are unknown.”

Permafrost also holds large amounts of carbon. And the beavers’ reengineering of the landscape can change the hydrology creating instability in the layers of carbon. 

Streams on the Alaskan tundra maintain a stable low temperature. And deep pond water created by the large rodents increases water temperatures in the winter.

Tape and his team of researchers published their findings in the journal Scientific Reports in May. And Tape presented the research to the American Geophysical Union in December.

Tape's team is sure the beaver ponds are thawing the surrounding permafrost and impacting the climate crisis. They just aren’t sure exactly how much damage is taking place. But it looks like a lot from space.