The benefits of beavers

21 February 2020

BEAVER-IN-WATER

A beaver chewing on a twig in water

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Reintroducing beavers to English rivers can reduce flooding, increase biodiversity, and increase tourism, scientists and wildlife conservationists have found...

The report, published on the Devon Wildlife Trust's website, looked at the impacts of beavers five years after reintroduction. Beaver dams were found to improve the resilience of land to flooding, by increasing water retention and slowing run-off into towns downstream.

“Beavers aren’t the sole solution to flooding,” says Dr Alan Puttock, scientific adviser to the River Otter Beaver Trial from the University of Exeter. “But natural flood management, including beavers, can be very useful for small communities that don’t qualify for large engineering flood defence structures.”

Until they were hunted to extinction four hundred years ago, beavers were found throughout the UK. Some accidental escapees into a river in Devon provided the scientists at the University of Exeter and Devon Wildlife trust with an opportunity: to figure out if the beaver can still thrive in modern British landscapes.

"The country is now much more intensely populated, and more intensely managed,” explains Puttock. "But the beavers were able to thrive. The population increased from two families to 13 families over five years.”

The beavers had such an impact on their environment because, like humans, they are what’s known as ecosystem engineers - animals that change the landscape to their liking, rather than adapting to the landscape as they find it. And when two ecosystem engineers clash, a little bit of ingenuity is required for them to get along.

“If you have dams that are flooding land to an unacceptable level, you can use something called a 'beaver deceiver' to artificially lower the level of the dam,” explains Puttock. 

The beaver deceiver is a pipe that is installed under the dam to remove water, with a cage over each end so it can’t be blocked subsequently by an over-eager beavers. So, although the benefits can be great, management is required to keep harmony between humans and beavers.

Luckily, examples of successful beaver management already exist. In Bavaria, Germany, beaver reintroduction has been so successful that their population has reached between 30 and 40 thousand.

“Their management strategy has a couple of regional beaver advisors, who are government funded,” Puttock explains. ”But then a whole team of volunteers within the land-owner community who can do the easy tasks such as protecting trees and removing dams.”

The results of the UK trial have been reported to the Government, who have extended the trial by six months so they can make a decision on the beaver’s long-term future. If they rule against the beavers, they’ll need to be trapped and taken to a zoo, but Puttock remains hopeful.

“I think we’ve shown that beavers can bring a whole range of benefits. I really hope, that with appropriate management strategies, we’ll be able to expand beaver populations across Great Britain.”

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