Research backs beavers in fight against flooding and droughts

Research led by the University of Exeter and Devon Wildlife Trust based on a ten-year study of wild-living beavers in Devon shows that the animals are having a positive impact on flood and drought alleviation.

Having been hunted to extinction 400 years ago, beavers returned to England’s countryside when a population was discovered to be living on East Devon’s River Otter in 2014. No one knows how or by whom the animals were reintroduced, but in 2020 the beavers were given the legal right to stay. The charity Devon Wildlife Trust monitors the animals and estimates that the industrious rodents are now living in 20 separate family territories along the river and its tributaries.  

Beavers are known as ‘ecosystem engineers’ for their unusual ability to shape their surroundings to suit themselves. They build dams on streams and other watercourses to create pools and wetlands where they feel secure to feed and interact with one another.

Now research data gathered by the University of Exeter and Devon Wildlife Trust over the past decade has revealed the remarkable impacts of this behaviour on local landscapes, people and wildlife.

By combining drone imagery with water depth monitoring, the researchers were able to examine the wetlands created by beavers in four separate family territories. The results show that together the wetlands were storing more than 24 million litres of water, with an average of 6 million litres stored per site. This is equivalent to around 10 Olympic-sized swimming pools of water being held behind the beavers’ dams.

The researchers also measured the impact of beavers on the flow of water through landscapes. Using data from the Environment Agency’s river gauging stations, researchers found that beaver dams and their wetlands can significantly reduce storm flows by an average of 30% during periods of heavy rainfall. The research points to the benefits for flood prone communities downstream of beaver wetlands as they slow the movement of water, reducing the peak flow levels in rivers and streams.

The slower movement of water created by beaver dams can also help to alleviate drought conditions. During hot and dry spells of weather – such as the 2022 drought which impacted large parts of the UK – the water stored in beaver wetlands was released slowly downstream, helping to maintain local river and stream flows, and producing ‘green oases’ in which wildlife such as toads, dragonflies and water voles could survive. 

Dr Alan Puttock, Lecturer in Applied Nature Based Solutions at the University of Exeter, was part of the team which conducted the beaver research. Dr Puttock said:

“Based upon over a decade of research at the University of Exeter we have found that beaver-created wetlands contribute significantly to more resilient landscapes, reducing both the impacts of flooding and drought. Above flood prone communities in the River Otter we have observed that beaver-created wetlands have significantly reduced storm flows.”

Devon Wildlife Trust is now using the research findings to make the case for creating more space for beavers and their wetlands. Landowners and farmers with beavers on their land can experience loss of income as areas of their fields become wetter and more challenging to manage. The charity is therefore undertaking a new approach to unlock financial support and provide alternative income to those who provide space for beavers and support the expansion of beaver-created wetlands.

In a first for England, Devon Wildlife Trust is using the Defra administered Farming in Protected Landscapes Grant Scheme to work with two local East Devon-based landowners who have beavers on their farmland. With the help of the charity and the East Devon National Landscape team, Clinton Devon Estates and Bicton College have been able to gain funding for providing space for beavers on parts of fields which were previously used for cattle grazing. The resulting beaver wetland is now estimated to contain around 12 million litres of water and has quickly become a home to other wildlife including otters, kingfishers and Cetti’s warblers.

One of the farmers involved in the project is Sam Briant-Evans, Head of Agriculture at Clinton Devon Estates. Sam said:

“The habitat that beavers have created here is a fantastic environment and we’re really proud of it. The new wetland is home to a huge range of insects and birds that would never have been here before. We’re very pleased by the support we’re receiving from the Farming in Protected Landscapes scheme – in particular because at the moment there are no other funding options for landowners who make space for beavers.

As farmers we’re already being encouraged to farm and manage the land in a more environmentally friendly manner so we hope that this type of support for beavers will become more widely available as the evidence of their positive impacts becomes better known.”

Ed Parrish is Direct of Land-based operations at Bicton College. Ed said: “As a working dairy farm attached to an agricultural college we wanted to take advantage of the unique learning opportunity for our students that comes with having a beaver wetland on campus, while continuing to operate as a commercial farming business.

This funding is a welcome recognition that having beavers on our land can have financial implications for farmers. We would like to see this type of funding expanded so that other landowners can be rewarded for the benefits they are providing to the environment when they allow beavers to create wetland habitats”.

Devon Wildlife Trust is working hard to roll-out this innovative ‘green finance’ approach to support other landowners and farmers in the South West who are interested in making space for beavers and their wetlands.

The Trust’s Green Finance Officer is Dr Holly Barclay. Holly said: “I’ve been lucky enough to see firsthand the incredible way that beavers can transform local environments and benefit a wide range of other species, including people! To maximise these benefits, we need to provide space along our waterways for beavers to live and create their wetlands. That’s why we are developing new funding streams which can reward land managers for the benefits they are providing to society – including flood and drought alleviation – by allowing beaver wetlands to develop on their land.

In the face of the climate emergency, where flooding and droughts are becoming more regular and severe, we need to be creative in our responses. Beavers and the help they can give us are one cost-effective natural solution to help tackle society’s growing environmental challenges.”