• 50 beavers in Devon, England, have won government backing to stay, following a five-year study on their impact.
  • 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.

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.

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.

And now, they have been granted official 'leave to remain' on the River Otter by the UK government after the Trust found the beavers had "delivered significant ecological benefits with new areas of wetland habitat created and managed".

In what has been hailed as a ground-breaking government decision for England's wildlife, environment minister Rebecca Pow said beavers could be considered a "public good".

13 beaver dams at Enclosed Beaver Site and water flow upstream (blue) and downstream (red) during a single high flow event.
Beaver dams on one stream slowed the flow of water - showing they could reduce flood risk.
Image: Devon Wildlife Trust

How beavers can help the environment

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.

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.

Researchers found the dams slow the flow of water. On average, peak flows were 30% lower leaving the site than entering.

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.

The report on the trial says that from a health and biosecurity perspective, beavers are considered to present "no significant risk to human, livestock, or other wildlife".

It also notes that the ecosystem services and social benefits of beaver reintroduction outweigh the financial costs incurred.

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