Beavers in Cornwall: Return of a Keystone Species

After being hunted to extinction in the UK 400 years ago, beavers are being brought back to Cornwall by Cornwall Wildlife Trust and partners Woodland Valley Farm. This ground-breaking project hopes to show that beavers can help create new wildlife habitat, make our water cleaner and crucially reduce flooding.

Beavers will be reintroduced to a fenced area, upstream of Ladock village, near Truro, that has suffered severe flooding. Our partner Universities will study the before and after impacts, building on research from reintroductions in the UK and across Europe. The results will help us find out if this native species could once again become part of the Cornish landscape to help us combat flooding – naturally.

The list of species that have been reintroduced following extinction in the UK is short; white-tailed eagle, great bustard, large blue butterfly and Eurasian beavers. We could perhaps be accused of favouring reintroduction of either large and charismatic or small and beautiful species, whilst neglecting extinct plants, fungi or less attractive animals. Beaver reintroduction however, is most definitely different. Don’t be fooled into thinking beaver reintroduction is about them being cute furry creatures, or that Cornwall is jumping onto a beaver bandwagon. There is no denying that beavers are large, charismatic animals; but there is far more to them than that.

Beavers are a keystone species; they significantly alter the habitat around them and as a result affect large numbers of other species. They are vegetarian, eating herbs and grasses near the water’s edge in summer and switching to bark and twigs in winter. Beavers create new and more diverse wetland habitats as they go about their business of dam construction, tree coppicing and canal digging. In a fenced project in Devon, a pair of beavers constructed 13 ponds, and amphibian numbers soared as a result. Freshwater insect numbers also increased significantly, providing food for fish. The Cornwall Beaver Project is monitoring fish species and numbers to see how they change over time and we will be sharing the results with local angling groups.

The Cornwall Beaver Project, run by Woodland Valley Farm and Cornwall Wildlife Trust, is working closely with Exeter University researchers to see what impact the beaver dams could have on flood prevention. Research on a small headwater stream in Devon has shown beaver dams and pools slow the flow of river water following heavy rain, potentially alleviating flooding downstream. The Cornwall Beaver Project will test whether or not we get the same effect on a larger stream.

By the same token, during drought periods beaver dams can reduce problems of low-flow in rivers by slowly releasing stored water. A happy side-effect of the slowing of the flow in beaver pools is that silt drops out of the water column, taking excess nitrogen and phosphates with it. Researchers found that river water flowing downstream of a beaver habitat was significantly cleaner than water flowing upstream. The Cornwall Beaver Project also hopes to study the levels of bacteria in water entering and leaving the beaver site. Bacteria from both human and livestock sources affects the quality of our bathing waters. Could the effect of sunlight on the water within beaver-created pools reduce the levels of harmful bacteria in streams and help enhance bathing water cleanliness? We plan to find out.

In the future, beavers and their engineering prowess could have far-reaching impacts. Wider unfenced reintroduction would bring significant change to Cornwall’s rivers over time; although not everyone will think this is a good idea. Across Europe, 26 countries have brought beavers back, so we have much to learn from those who have already experienced their return. Interesting times lie ahead when, as a society, we decide whether we want these animals back in the wider countryside. For now, let’s just enjoy seeing how the Cornwall beavers settle in and create new habitats at Woodland Valley Farm and collectively learn more about what these fascinating creatures can do.

To find out more about the Cornwall Beaver Project, click here. 

~ Cheryl Marriott
Head of Conservation, Cornwall Wildlife Trust
Adviser, CFWI Environment & Public Affairs Sub-Committee