The National Trust is releasing beavers into large enclosures at two sites in the south of England in the spring to boost wildlife and help combat flooding.
The schemes, which have been given the go-ahead by Government conservation agency Natural England, will see two pairs of the aquatic mammals each released into a separate enclosure at Holnicote, Somerset.
A third pair will be released into a fenced enclosure at Valewood on the Black Down Estate, on the edge of the South Downs in West Sussex.
Beavers were once native in Britain but were hunted to extinction in the 16th century, though they have made a return to the wild in some parts of the country, including in Scotland and a small number on the River Otter in Devon.
They can also now be found in several areas in large enclosures where they are helping manage the landscape and habitats.
The animals are a “keystone” species, which means they manage the landscape around them, building dams, creating pools in rivers and streams that store water and slow the flow of the water downstream.
This is the first time the National Trust has released beavers on to its land, and it hopes the pairs at the two sites will help create a thriving habitat and increase the range of species and wildlife numbers.
It is also hoped they will help make the landscape more resilient to the extremes of climate change, storing water in dry times and reducing the rising risk of flooding.
At Holnicote, on the edge of Exmoor, the pairs will be released into two woodland enclosures of two hectares (five acres) and 2.7 hectares (6.7 acres) in size, alongside tributaries to the River Aller.
Ben Eardley, project manager for the National Trust at Holnicote, said: “Our aim is that the beavers become an important part of the ecology at Holnicote, developing natural processes and contributing to the health and richness of wildlife in the area.
“Their presence in our river catchments is a sustainable way to help make our landscape more resilient to climate change and the extremes of weather it will bring.”
The beavers at Holnicote will be part of a new project on the estate to restore the streams and rivers to a more natural state where they meander “like the branches of a tree”.
“The dams the beavers create will hold water in dry periods, help to lessen flash-flooding downstream and reduce erosion and improve water quality by holding silt,” he said.
At Valewood, the beavers will be introduced into a 15-hectare (37-acre) enclosure on the site which includes pasture, mixed woodland, two streams at the head of the River Wey catchment and areas of wetland.
David Elliott, National Trust lead ranger for Valewood in the South Downs, said: “Beavers are nature’s engineers and can create remarkable wetland habitats that benefit a host of species, including water voles, wildfowl, craneflies, water beetles and dragonflies.
“These in turn help support breeding fish and insect-eating birds such as spotted flycatchers.”
The beavers are expected to create little ponds, dams and rivulets along the stream at Valewood, making habitat that suits them and other wildlife.
They will be brought from Scotland, from the River Tay where they have been breeding since being illegally released some years ago, and will be released in the spring – with the trust spending the next few months readying the sites.
Both projects will be monitored with help from Exeter University and other organisations, looking at the environmental and water system changes to the landscape.