WOULD YOU WANT BEAVERS IN YOUR BACKYARD?

Before the 1700s, the Eurasian beaver was one of the UK’s key native mammal species, although today many would find it difficult to imagine walking past a river and seeing a beaver-built dam or, better yet, its residents.

Hunted for their fur, meat and a salicylic acid cureall called castoreum from their castor sacs, beavers disappeared from Great British woodlands and wetlands sometime in the 16th century, though nobody is quite sure exactly when. However, after 300 years, small populations of the furry rodents have begun to flourish in parts of southern England and Scotland. But it is not just the beavers who are flourishing; the degraded ecosystems they have re-inhabited have benefitted greatly under their stewardship. This effort has been carried out mostly by independent UK landowners, supported by the Beaver Trust, an ecological restoration charity. Its core programme, Mainstream, aims to make beavers a key species in the UK once again. They do this by encouraging and advising farmers and landowners on how to acquire funding grants and non-native animal keeper licences to introduce Eurasian beavers onto their land. It is natural restorative efforts like these that, if scaled up, could help to combat Britain’s biodiversity crisis.

Before their extinction, beavers were a fundamental component of both ecosystems and local economies and could be found across the entirety of Britain. They thrived on wetland habitats and in ancient woodlands, helping to manage the flow of water throughout the ecosystem by building dams, and maintaining those conditions so other animals could thrive. Inhabitants of the wetlands, such as small birds and amphibians, also co-evolved with beavers, including a now extinct species of European hippopotamus.

Eurasian beavers were a valuable commodity for local people in small villages right up until the 1700s. They hunted the beavers for their extremely soft waterproof pelts that were in high demand for warm clothing, especially as the rodents became increasingly rare. The cure-all castoreum, a form of salicylic acid from the beavers’ castor sacs, which are used for marking territory, was also harvested, and sold to be used in perfume and even by beekeepers in the Middle Ages to increase honey yields. In fact, today, castoreum is still used for notes of leather in perfume and even as a food additive, albeit in increasingly small amounts. Before their disappearance from the British countryside, beavers even taught medieval foresters the technique of coppicing. Coppicing is the practice of cutting trees down to the base repeatedly, producing the wood needed by local communities while promoting new growth in the old tree to keep it in production year after year while also maintaining essential habitat and stabilising the soil. It turns out humans were not the first species to learn how to manage forests sustainably – beavers got there first!

Dubbed by scientists as ‘ecological engineers’, beavers are so important to their ecosystems because they provide essential ‘ecosystem services’. This includes benefits such as water purification, reduced flood risk, restoration of wetland areas and even greenhouse gas sequestration as healthy wetlands, especially those containing peat, serve as huge stores of carbon.

Arguably the most important service provided by beavers is dam building. This favoured pastime of the Eurasian beaver has helped new populations convert drained farmland back into the thriving wetlands of nearly 400 years ago by raising the water table and the land itself as well as increasing the size of the river and purifying it of agricultural runoffs, such as nitrates and phosphate from fertiliser, benefitting natural communities downstream and preventing leached chemicals from reaching the ocean. Before a dam is built, the waterways snaking through fields have often cut deep into the ground rather than spreading outwards, forming a deep ditch, and causing a lowering of the water table. When beavers construct a dam, the water flow is diverted around it, widening the stream channel, and causing deposition of sediment on the inside curve of the meander that helps to raise the level of the stream bed. When the stream bed level is high enough, water is forced onto the field floodplain, restoring the groundwater level, and providing the water needed for more diverse plant species, and by extension the animals that depend on them, to return to the area. As more dams are built and more waterway diversions occur, complex water systems emerge, and wetland habitats or woodland waterways can be fully restored. This means that endangered or vulnerable UK wetland species, such as water voles, kingfishers and curlews, can benefit indirectly from the presence of beavers. With over 10% of our wetland species under threat in Britain, the re-introduction of beavers is a vital tool at our disposal to protect and conserve some of the most threatened wetland and ancient forest habitats in the world.

Beavers can also benefit humans with their feats of aquatic engineering. According to a paper published by Prof. Richard Brazier et al. from Exeter University, the beaver dams studied reduced average flood flows by up to 60%. With humancaused climate change causing rising sea levels across the world, combining natural solutions such as beaver dams with human engineered management could both reduce costly damages to human life and property from flooding and help to draw out carbon from the atmosphere, as well as boosting the UK’s biodiversity.

Today, around 90% of Britain’s wetland habitats have disappeared due to over-abstraction and farmers draining their land of water, encouraged by government subsidies. This means that, if Britain wants to increase its biodiversity from the meagre 53% it currently maintains, then re-introductions and re-wilding projects must become widespread. Thankfully, progress is being made, albeit at the local level. Tiring of government bureaucracy, landowners such as Merlin Hanbury-Tenison, owner of the temperate rainforest Cabilla in Cornwall, have returned beavers to riparian woodlands or ecologically restored areas by going around the UK government and working with organisations such as the Beaver Trust and Natural England. Since the release of a male and female beaver pair in July 2020, two beaver kits (baby beavers) have been born on Hanbury-Tenison’s site. His goal is to increase the area that his forest covers three-fold and re-introduce even more formerly native species. The current population of beavers in England and Scotland stands at around 1,500 individuals, with two thirds of them residing in Scotland. However, growth of this population is expected, especially after the government gives English beavers protected status at some point this year, and re-wilding efforts, such as those championed by the English musician Ed Sheeran, become more popular.

The future seems bright for Britain’s beavers, as the Beaver Trust plans to expand their beaver populations to ultimately cover the whole of the UK, matching the territory the beavers occupied pre-extinction. With the British public onboard, a new age of environmental restoration instead of degradation may be taking off in Britain, and perhaps beavers will once again become a regular sight on British waterways.