• Hunted to extinction in Britain, a small number returned a decade ago.
  • Researchers say they’re having a positive impact on wetland ecology.
  • Effects observed include creating new habitats for wildlife.
  • Some people are concerned the animals could damage farmland.

Wild beavers hadn’t been seen in England for hundreds of years. Then, in 2008, a colony appeared on the banks of the River Otter in the county of Devon after escaping from captivity.

In 2015, a few were captured, tested for disease and released back into the river after receiving a clean bill of health.

Since then, they have been under observation as part of a trial run by the Devon Wildlife Trust, designed to demonstrate that beavers can have a positive impact on their natural environment and create benefits for the local community.

Researchers involved say the beavers’ activities over the past five years have helped manage water flow, raising the possibility that their dams could help reduce the risk of flooding further along river systems.

The beavers’ handiwork has created new habitats for wildlife living around the river, including water voles, otters, and wading birds, according to the trust. It says their building is also giving plants more direct access to sunlight and encouraging the regrowth of native species such as willow.

Some local farmers are less convinced. Britain’s National Farmers’ Union opposed the reintroduction of beavers to the River Otter over concerns about damage to farmland and the spread of disease. It suggested that the beavers’ legal status of “not ordinarily resident in Britain” be retained even after the trial.

Devon Wildlife Trust has established a “beaver hotline” to respond to any landowner concerns, and says preliminary findings from the trial have demonstrated the value of the beavers to wetland ecosystems and water management.

Since 2011, the trust has also been studying beavers in an enclosed project on private land. Since their introduction to the site, it says, the beavers have constructed 13 dams, holding up to 1 million litres of additional water within ponds on the site. During storm events, on average, peak flows were 30% lower leaving the site than entering.

The UK trial is set to end in March 2020
Image: Mike Symes/Devon Wildlife Trust

The River Otter trial is due to end in March 2020, when the government will determine if a wider reintroduction of wild beavers to UK rivers is viable.