Beavers are ecosystem engineers, capable of changing landscapes through the construction of dams, which can alter the stability of permafrost and impact the flow of water, fish populations and local livelihoods.

Beavers reshape and record the tundra

Led by researchers from Anglia Ruskin University (ARU) in Cambridge, England, this new study shows that beavers leave behind a datable environmental record. Their browsing creates scars within the growth rings of shrubs, and their dams generate hydrological changes detectable from space.

Their northward expansion is thought to be driven by climate change, with the Arctic tundra experiencing increased shrubification. Species such as Salix (willow) and Alnus (alder), which provide food and construction material for beavers, have become more abundant as temperatures rise.

Working alongside the Indigenous environmental guardian and monitoring group, the Imaryuk Monitors, researchers surveyed locations in the Inuvialuit Settlement Region from Inuvik north to Tuktoyaktuk, on the coast of the Arctic Ocean, recording 60 beaver lodges or dam sites and collecting Salix and Alnus stems containing scars from beaver browsing.