Beaver Reintroduction

The Eurasian beaver is Britain’s largest rodent, belonging to the same group as mice and voles. With a flat, paddle-like tail  and webbed hindfeet these impressive aquatic mammals are suited to life both on land and in the water. Described as ‘ecosystem engineers’, beavers build dams to create access to deep pools of water, and diversify surrounding vegetation by coppicing deciduous trees for winter food and for building supplies. Beavers are very family-orientated usually living in family groups of six to twelve individuals comprised of an adult pair, kits and yearlings. Living a nocturnal lifestyle, beavers sleep in lodges or burrows throughout the day, and are active between sunrise and sunset.

A mature adult beaver typically grows to a length of 70-100 cm, with a tail length of 30cm – 40cm,  and weight between 18-30 kg. Beavers have an average lifespan of 10 to 15 years.

Beavers are herbivores, so follow a completely vegetarian diet. Throughout spring and summer, beavers will eat a variety of herbaceous terrestrial and aquatic plants, flowers and grasses, and even create ‘beaver lawns’ where grass has been neatly grazed. Throughout autumn and winter, they switch to a more woody diet, which leads to increased tree coppicing activity. Through winter, forward-thinking beavers will create a winter larder in their pools, caching small tree branches which they can rely upon if food resources decrease. Contrary to common belief, beavers do not eat fish.

Beavers can carry host-specific parasites not currently present in Britain, though these are not known to infect or harm other species of wildlife, livestock or humans. Other parasites carried by beavers are already present in British wildlife, livestock and humans and these other sources of infection pose a more significant risk to water contamination than beavers. If beavers are released into Ennerdale they will be quarantined and health screened by a specialist vet to ensure they are not infected with any disease.

Yes, there are established populations of beavers in the east and west of Scotland, as well as enclosed trial releases small free-roaming colonies in England.

Beavers were reintroduced to Knapdale, West Scotland, in 2009 through the Scottish Beaver Trial, coordinated by Scottish Wildlife Trust, RZSS and Forestry and Land Scotland. Prior to this, in 2000, an unofficial release of beavers onto the Tay catchment , in East Scotland, was undertaken – and which has now established a strong population of free-living beavers

As of May 2019, the Eurasian beaver became designated as a protected species in Scotland.

In England the largest free roaming population is on the River Otter in Devon. Following a five-year trial period, this population was recently permitted by the UK Government to continue. There are also a number of fenced projects across the country, including in Cornwall, Yorkshire and Essex amongst others. At present, a licence is required for any beaver reintroduction project.

In Cumbria, a pair of beavers were released into an enclosure on the Lowther Estate near Penrith in summer 2020, following the approval of a licence in January 2020. For more information on this project, visit www.cumbriabeavers.org.uk .

If supported and approved, the release of beavers in Ennerdale would be the largest reintroduction in England to date. The scale of the landscape and interactions with faming, forestry, freedom of public access and tourism make Ennerdale a unique upland site.

In general terms, beavers are well-studied as contributing to reducing the risk of flooding lower down in river systems by building dams and moderating water flow. The modifications made by beavers to streams can raise the water table locally, creating wetland areas to the benefit of biodiversity. Evidence from the River Otter beaver trial in Devon, and from beavers in the River Tay in Scotland, show that instances of beaver dams creating undesirable flooding are uncommon, localised and usually small-scale. In these situations dams are simply removed or pipes (‘beaver deceivers’) are placed through them to manage water levels.

Evidence from Europe and the River Otter trial in Devon shows that beaver damage is, in the vast majority of cases, small-scale and localised. Where localised problems occur, there are a number of well-established methods in place. These include the removal of dams, the introduction of overflow piping, or the installation of fencing (as one does for deer and rabbits). Beavers have been known to forage certain crops if located directly beside a waterbody.

Beavers , by their nature , leave little evidence of the presence behind them. Their dams and pond systems will not , in most  cases, be visible many decades later. Being water based creatures their dead bodies would have mostly decompose in the water environment. Often archaeological evidence of past habitats, creatures and human activities is found during pre construction archaeological investigation. However construction mostly occurs on dry land not in wetland or habitats dominated by water so the remains of beaver are less likely to be found.

One very recent finding was during the excavation at Stainton West as part of the Carlisle Western Bypass planning works. The report says "The excavated site covered 0.6ha, within the footprint of the road, but seems to extend outside this, towards both the north and the south. It comprised a series of palaeochannels, with a dense in situ scatter of struck lithic material (c 300,000 pieces) occurring on an island between two of these. Finds of worked wood and stone within the channels, associated with well-preserved palaeoenvironmental assemblages, indicate various phases of human activity. The earliest of these, dating to the 6th millennium cal BC, probably represents the opportunistic reuse of beaver-made structures by people."

Whilst not Cumbria another North of England recent find is in Northumberland. "A wood specimen with beaver gnaw marks was recovered from the bank of the Scaup Burn in Kielder Forest in Northumberland. The marks were analysed, the tree species were identified and the sample was radiocarbon dated to between 1269 and 1396. Other wood remains in the same context suggest a most likely dating between 1330 and 1390. This find represents the most recent radiocarbon-dated physical evidence of beaver yet found in Britain, by at least 400 years. In conjunction with documentary and other archaeological evidence from the period, this discovery indicates beaver were present within the Tyne River catchment up until at least the 14th century ad. In addition, this find highlights the need to investigate all possible evidence of beaver fully when discovered and to remain open-minded about the possibility of making finds in unexpected locations and contexts. " Its difficult to think of a reason why beavers would not be in Cumbria when they were in Northumberland.

As is often said in crime investigations "lack of evidence is not proof of absence". Take the Pine Marten, we have no physical evidence that Pine Marten were ever in Ennerdale. However an area of Crags to the east of Side Wood is named Mart Knott suggesting they were inhabited by Pine Martens at one time in the past.