BEAVER REVOLUTION
For five years, a secret colony of wild beavers has been utterly transforming a west Devon valley. Fergus Collins explores an astonishing landscape of ponds, marshes and dams – and looks at the wider impact on wildlife and local people
A new wild colony of these amazing aquatic engineers has appeared in Devon – and transformed the landscape. Fergus Collins investigates.
Somewhere between Dartmoor and Bodmin Moor lie green valleys, hamlets and farms forgotten by travellers on the A30 heading west to Cornwall. But in one of these combes, a revolutionary engineering project is taking place. A part of a tiny unnamed tributary of the River Carey has been completely remodelled by wild beavers – a population not widely known about. I had the privilege of visiting and judging for myself why there’s so much noise about this industrious rodent, which is making a comeback in Britain after a 400-year absence.
Beavers first appeared on the stream in 2013. The water flows through 50 acres belonging to the hotel and farm at Coombes head owned by Tina and Tony Bricknell-Webb. It was Tina who first photographed a tree gnawed in cartoon fashion a mere eight inches from its base so that it toppled into the water.
The Bricknell-Webbs knew exactly which animal had done this and where it had come from. Beaver expert Derek Gow lives on the next farm and keeps captive beavers for official reintroduction projects. Some had escaped. Tony and Tina were keen to see what happened next – so they left the animals alone.
Before the beavers arrived, the stream was a fast-flowing channel, reduced to little more than a tree-shadowed drainage ditch to hurry water off the farmland and into the Carey down the valley. The beavers quickly changed that.
THE DAMMING INSTINCT
Beavers are slow and awkward on land – they need water. They are also stimulated into action by the sound of running water; they instinctively dam it. The dams eventually
create large, deep pools and canals that the beavers use to get around, safe from predators. They dig their lodges into the pond banks, with the entrances underwater for added safety. Not that they have predators in modern Britain.
My previous experience with beavers was on the River Otter in east Devon. Here a population of unknown origin had made press headlines while Natural England and Devon Wildlife Trust debated what to do with them (they are staying but closely monitored). The Otter is a large river with enough water for the beavers not to need dams, so on my visit I saw a few gnawed trees but no engineering. What I saw in west Devon was different: possibly the most astonishing wildlife spectacle I have ever witnessed in Britain.
In five years, the beavers have been busy. Working at night, they have cut down dozens of small to medium ash and alder trees along the stream, eating the uppermost shoots and twigs and using larger branches as the bases for their dams. The wood isn’t laid willy-nilly. The beavers place larger pieces as struts against the flow of the water, then weave smaller lateral branches to create a mesh. Mud is balled and wedged into the gaps, creating a solid bank. They keep raising the dam until the water reaches a depth they like. Water can still leak through the dam and seems to emerge as a sheet, rather than a narrow channel.
But there is not just one dam, but at least 15, varying in width and depth as the beavers surmount the challenges of the valley. One dam section is at least 3m high, another 15m wide. The result is a chaotic series of pools, canals and boggy areas. Through their logging, the beavers have opened up areas, allowing light and life in, and shoots are emerging from each stump – a natural coppicing process.
WHAT OF THE AUTHORITIES?
Tony and Tina led me around the valley for three muddy hours. Signs of the animals were everywhere, from webbed footprints to worn paths between the pools. But despite staying up late and then a dawn start, I didn’t see the animals – defeated by the unseasonal wind and rain that kept the beavers in their lodges.
I was full of questions – how many beavers are working here and how on earth has this
escaped the attention of the authorities that licence reintroductions, in this case Natural England? What effect are all these dams having on fish and other wildlife? And how do farmers feel about the beavers in their valley?
Fortunately, after the unsuccessful dawn attempt at seeing the animals, we were joined by Derek Gow himself. He admitted that badgers had dug into his beavers pens, allowing a small number to break out, but he had no idea how many are at large now.
Some farmers have expressed disquiet about losing land on the edge of the stream as the rising water levels in the pools created marshy fringes. But most people in the immediate vicinity like to see these extraordinary animals in the wild. Derek admitted that if the beavers were to spread, there are likely to be landowners downstream who would not want beavers on their land. On the River Tay in Scotland, where there are some 400 wild beavers, many landowners are angry about how the animals have punched holes in flood protections and productive land has been lost. Some animals have been shot.
But what about the authorities? Natural England, which licenses all reintroductions, has visited but, as the escape is confined to the Bricknell-Webbs’, nothing has been done. As the hotel is gaining a name as somewhere to see unusual wildlife, the Bricknell-Webbs have welcomed their new tenants. Natural England told me it is: “working with the landowner to contain the beavers at Coombeshead and reduce the risk of environmental impacts caused by the animals, such as tree damage.” And what about the landscape, environment and wildlife? Derek explained that the open series of lightly wooded pools and marshes are great for birds and invertebrates – certainly more welcoming than the dark, narrow drainage ditch that had been there. Tony has noticed a massive increase in clumps of frogspawn.
And what about fish? Some angling groups, led by the Angling Trust, oppose beaver reintroductions, arguing that their dams impede fish movement. “Nearly all fish species, not just trout and salmon, need to migrate up and down rivers in order to complete their life cycle and the addition of
“The open pools and marshes were great for invertebrates and birds”
beaver dams would only increase the number of obstacles that fish have to overcome,” said Mark Lloyd of the Trust.
Derek Gow disagrees: when the stream was in spate, enough water poured over the tops and sides to allow trout to move between the pools. “That there are any fish this high up the stream is entirely due to the beavers. Fish primarily need water and beavers provide it.”
He and Tony offered anecdotal evidence that the trout are more numerous and larger than before due to increased food and security provided by “underwater complexity” created by the beaver. This is backed by preliminary results from studies on the River Tay by the University of Southampton, suggesting that trout are larger and more abundant in beavermodified habitats compared to very similar river habitats with no beavers.
“WE SHOULD WELCOME BEAVERS”
But that’s not the end of the story. I spoke to Alan Puttock of Exeter University, who has been studying the impacts of the beavers’ activities on water flow and quality. The small streams in this area carry a huge load of water after heavy rain, which often contains silt and agricultural run-off and results in flooding further down. He has found that, compared to similar sized streams, this tributary had a far steadier year-round flow, delaying the impact of heavy rain on the stream and keeping water flowing upstream in summer. In the closely monitored Tamar project, hard evidence shows that the dams allow silt to settle, and act as partial filters for fertilisers and other chemicals (see box, page 35).
Derek Gow is strident, even angry, in his support for the beavers. “Much of this landscape is ecologically dead. We have spent decades, and billions, promoting the destruction of our biodiversity through CAP payments to farmers. The beavers bring life back into our countryside and we should welcome them.”
I was disappointed not to see the animals and made immediate plans to return. But in many ways, the impact of the beavers is more important. They have utterly changed a landscape, blending land and water to create a haven bursting with life. Arguments will rage about the positive and negative impacts of beavers for years to come but, for me, this felt like the beginning of a wildlife revolution.