Beavers back in British rivers

The UK has seen widespread flooding this month following the arrival of storm Dennis and his sidekicks. The deluge has totally overwhelmed flood defences in many places. These defences are often necessary because poor land stewardship has drastically reduced the ability of the ground to store water. Until they were hunted to extinction, beavers were the UK’s land managers: their building projects helped to control how water moved through the terrain. So might one solution be to bring them back? Well, for the first time in four hundred years, they are swimming wild again, at least in one river in England. And - in the words of one correspondent, their impact has been “dam impressive”. Megan McGregor spoke to Alan Puttock, who’s one of the researchers keeping an eye on them...

Megan - Beavers are staging a comeback in a corner of southwestern England. Some accidental escapees into the River Otter provided scientists at the University of Exeter and Devon Wildlife Trust with an opportunity - to figure out if the beaver can still thrive in modern UK landscapes. And five years later the results are looking positive.

Alan - Beavers were able to thrive in our modern British landscapes, the population increased from two families to thirteen families over the course of five years and we found that overall beavers had a positive impact. This was in terms of holding back water and reducing flood risk, a massive increase in wetland habitat and biodiversity and also some other more social benefits, such as ecotourism. For instance, there were local villages that benefited from increased visitor numbers with people who wanted to come and see these wild animals.

Megan - Since beavers went extinct, we humans have created a lot of concrete paved cities and compacted farmland. These landscapes drain water very quickly and can contribute to increased flooding. Luckily beaver dams have a rather handy side effect for humans.

Alan - By building dams within the landscape, beavers increase water storage, but also the roughness of the landscape. So they slow the flow of water. So when you get heavy rain events, rather than water rushing off the land and flooding, for instance, downstream communities, you get this slower release of water from a beaver impacted sight. Beavers aren't the sole solution to flooding. They are part of the solution. We're not saying that you should take away these flood defenses that currently exist. What beavers can do is increase the resilience of flood defenses, so by reducing flooding a little bit you might not see, say, flood walls overtopped during flooding.

Megan - The beavers have such an impact on their environment because, like humans, they're 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.

Alan - There were some negatives or management issues, such as localised inundation of farmland. If you have dams that are flooding land to what's deemed an unacceptable level, you can use something called a beaver deceiver. It's essentially a pipe to artificially lower the level of a dam. You essentially fool the beaver. The beaver thinks the dam's still there, but you can use this pipe to control the water level. So you still get much of the benefits of the dam, for instance, holding water back. You've got this habitat created, but you can lower the water level down to what's deemed an acceptable level, say for a neighbouring farmer.

Megan - So the beaver benefits can be big, but they require management to keep clashes with humans to a minimum. Luckily those hoping to bring the beaver back can learn from other successful examples of re-introduction, such as the programme in Bavaria in Germany,

Alan - Beaver re-introduction happened there a couple of decades ago. They probably have around thirty, forty thousand beavers there and they've introduced a very pragmatic management strategy where you have a couple of regional beaver advisers who are government funded, but then a whole team of volunteers within the farmer and land-owner community who can keep them updated and do easy tasks such as protection of trees or removing of dams if they're in a undesirable location.

Megan - And what does the future hold for British beavers?

Alan - We have now reported to government and we've provided them with all of our findings and they've extended the trial in River Otter by six months, which is to give them a chance to assess all the evidence and make a decision both upon the River Otter beavers and also beavers nationally.

Megan - If the government rules against the beavers, they'll have to be trapped and sent to a zoo.

Alan - I think we've shown that beavers can bring a whole range of benefits. I really hope that under appropriate management strategies we'll be able to expand beaver populations throughout Great Britain.