A trial of beavers living wild on an English river for the first time in centuries shows they can live alongside people and deliver benefits for nature and communities, experts have said.
As the five-year trial of the beavers on the River Otter in Devon and its catchment draws to a close, conservationists say the aquatic mammals have been creating habitat and helping wildlife such as water voles.
The animals, which were hunted to extinction in Britain around 400 years ago, could also play an important role in managing water in the face of climate change which will bring more floods and droughts, the evidence shows.
Beavers had been living wild on the south Devon river for up to a decade when the trial began in 2015, but faced being re-homed in captivity after evidence emerged that they were successfully breeding.
Plans for a monitoring trial were put forward by Devon Wildlife Trust, with the backing of local people, and were given the green light by Government agency Natural England, with the two family groups allowed to remain on the water.
The trial saw five more beavers released on the catchment to improve the genetic diversity of the animals, and the Trust says there are now at least seven breeding pairs – and possibly as many as 13 families – on the Otter.
In some of the territories, they have not had much impact, because they are living in the deeper water that they like, according to Devon Wildlife Trust’s Mark Elliott, who leads the Devon Beaver Project.
But where they have set up home in wetland or stream systems upstream, building dams to create the ponds they feel safe in, they have had a significant impact.
They have created “beautiful areas of new habitat”, benefiting water voles, otters and wading birds such as snipe and woodcock.
“It’s been really beneficial from a conservation point of view,” he said.
As part of the trial, experts from the University of Exeter examined the impact on water flow and quality, fish populations, vegetation and how the beavers affect people.
Professor Richard Brazier, who led the research, said of the impact on the catchment’s water flow, or hydrology: “It’s an amazing story, it’s far more change than we expected.”
The beaver dams significantly slow the flow of water downstream and reduce the peak flows after heavy rain, potentially protecting against flooding.
They also keep water in the streams in times of drought.
Research shows the dams catch sediment and inorganic fertilisers being washed from farmland, causing plant life to flourish in the beaver ponds and boost other types of wildlife, Prof Brazier said.
Despite concerns from anglers that dams could make it harder for fish to swim upstream to spawn, Prof Brazier said the research showed positive changes with fish living in the food-filled ponds, and still able to navigate the river.
The beavers have also attracted tourists to the River Otter, benefiting local businesses such as pubs and cafes.
There have been some downsides too, with landowners facing localised flooding or the beavers – who mostly favour willow – targeting orchard trees near the river.
Prof Brazier said: “Overall, the social and economic benefits of having beavers in the landscape far outweigh the costs, but the costs tend to be borne by different people from those who benefit.”
The experts said a proactive management strategy was needed to prevent conflicts between people and beavers, and that payments, such as through agri-environment schemes, could support affected landowners.
Overall, Mr Elliott said: “The evidence is certainly positive in terms of showing people and beavers can live alongside each other.
“Because of the benefits they have I would like to see beavers reintroduced across large parts of Britain.”
National Farmers’ Union senior countryside adviser Claire Robinson said the results from trials like that in the River Otter would need to inform a wider discussion with farmers before decisions on beavers in the landscape were taken.
“In the case of beavers, we do have concerns about the potential damage to farmland and the landscape caused by their physical activities.
“It is crucial that farmers have the tools to manage any impacts a beaver reintroduction could have,” she said.