Wild Life Dam it!
The beavers are back
Floods might be furthest from your mind following a scorching summer, but while we’ve been sun bathing, these cleaver creatures have been busy building nature’s best flood defences – a dam
Eurasian beavers have bred in Cornwall for the first time in several centuries. On the one hand this could be viewed as a small thing; two animals in a fenced enclosure has become four. On the other hand, this could be the start of something hugely significant; for people and wildlife. We are just beginning to understand what these animals are capable of if we give them the space to dam, dig and coppice; returning our streams to a wilder state not seen for generations.
It’s over a year since a pair of UK captivebred beavers was released into five-acre enclosure at Woodland Valley Farm near Truro. The site has been transformed, there are new beaver-created pools and coppiced trees creating open, sunny glades perfect for flying insects, bats and birds. Frog numbers are increasing, grass snakes are breeding and wading birds never seen before at the farm are turning up. On one of the weekly public beaver walks the group was treated to a display from a polecat, also never seen at the farm before! It may have turned up anyway of course, but there is no doubt that the local wildlife is benefitting from the beaver’s presence.
The Cornwall Beaver Project was
spearheaded by Chris Jones who farms Woodland Valley; he was keen to see if the dam-building activities of beavers could slow the flow of the stream that runs through the farm on its way to Ladock, a flood prone village. Chris teamed up with Cornwall Wildlife Trust and together we ran a successful crowd funding campaign to get the large enclosure built and the beavers in. The University of Exeter’s research into how water moves through the site, led by Professor Richard Brazier, is a critical part of the Cornwall Beaver Project. Results from a growing number of beaver re-introductions show that beaver dams slow the flow of streams, reducing peak-flows which could be significant in reducing flooding.
The thinking behind flood prevention has shifted in the last 10 years. Now there is an increasing focus on holding water in the landscape for longer, slowing the flow rate of streams so that rivers further down the system can cope with heavy downpours. Getting soil management right through
‘The site has been transformed, there are new beaver-created pools and coppiced trees creating open, sunny glades perfect for flying insects, bats and birds. Frog numbers are increasing, grass snakes are breeding and wading birds never seen before at the farm are turning up.’
sympathetic farming practices is a top priority, but once the water is in a stream, slowing down the speed of the flow can act as the next line of defence in combating flooding. At Woodland Valley farm before the beaver were re-introduced, water in the stream used to pass through the enclosure and the single manmade pond in 15 minutes. Now there are six sets of beaver dams, with more under construction. Water percolates through and around these dams and new streamlets have appeared in areas previously dry. The researchers tell us that water now takes an hour to move through the site; this is four times slower than before the beavers moved in. The activity of four beavers may not be enough to prevent Ladock from flooding, but it could be part of the solution. Beaver dams can also be useful in dry conditions; making water available to plants and other wildlife species when other areas have long since dried up. The long dry spell we had in June and July this year reminds us that even in Cornwall drought can be an issue, and this is likely to happen more regularly as our climate changes.
So what next for beavers in Cornwall? The honest answer is we don’t yet know. The research continues, including a new study to look at bacteria levels in the water originating from livestock upstream. Might the action of ultraviolet light on the shallow beaver-created pools have a sterilising effect? We aim to find out. If it does, then there may be positive implications for the quality of bathing waters and shellfish production, both very relevant to Cornwall. Going forward, the English government might follow Scotland’s lead and recognise beavers as a reintroduced native species. We may then start to see more re-introductions, with or without fences. It is becoming clear that we have a lot to gain as a society from having this keystone species back, but we would need to be prepared to offer landowners pragmatic advice and help when the activities of beavers are in conflict with the land use. Twenty-seven countries have gone before us and have learnt to live alongside these impressive herbivores once again. When we met Gerhard Schwab, a beaver expert from Bavaria, Germany he gently poked fun at us for having beavers inside a fence: ‘what do you need a fence for, you are an island’. We can learn a lot from countries like Germany that have already travelled the journey we are just beginning.
Cornwall beaver dam building
One of Cornwall’s beavers tucks into brambles
Leaky beaver dam at Woodland Valley Farm
Cornish Beaver kit