How Reintroduced Beavers Are Helping Britain Prepare for Drought and Wildfire

At the Holnicote estate in Somerset, southwest England, most of the surrounding countryside has been dry and dusty for much of the summer, but one corner has stayed green. Beavers, reintroduced there six years ago after being hunted to extinction in Britain in the 16th century, have turned a small watercourse into a wet meadow. Researchers say the example shows how reintroducing beavers more widely across Britain could help the country prepare for future droughts.

Beavers are often called ecosystem engineers because they fell small trees, build dams and dig channels. Water backs up behind their dams, spills across valley bottoms and soaks into the surrounding soil, while sediment and woody debris accumulate and wetland plants establish themselves. The result can be a mosaic of ponds, channels, marshes and wet woodland that keeps soil and vegetation wetter for longer during dry weather.

A 2008 Canadian study of 54 years of aerial photographs from Elk Island National Park in Alberta found that the number of active beaver lodges explained more than 80% of the variation in open-water area. In 2002, the driest year studied, beaver wetlands held nine times more open water than areas without beavers. British research points the same way: four wild beaver territories in Devon were estimated to hold more than 24 million liters of water in their wetlands.

Because healthy, damp vegetation is harder to burn, beaver wetlands may also help interrupt a fire's progress. A 2020 study of five wildfires in the western United States found that streamside vegetation in beaver-dammed areas was affected only one-third as much as comparable areas without beavers. Researchers caution this is not proof that beavers will always stop British wildfires, since landscapes and vegetation differ, and a wet strip beside a stream is no substitute for proper wildfire prevention.

Beaver dams can also flood farmland, block culverts and damage trees, so England now requires a license and a management plan for any wild beaver release. In Norfolk, two wild beavers that appeared on the River Wensum have produced the county's first kits, or baby beavers, in more than 500 years, an event some suspect followed an illegal release.