The case for and against the reintroduction of beavers in Britain

Two experts argue the case for and against the reintroduction of wild beavers in Britain.

The argument against reintroduction:Why we should not reintroduce beavers to Britain’s rivers

Mark Lloyd, Chief Executive of the Angling Trust explains why beavers should not be reintroduced in Britain.

The Angling Trust warmly welcomes Defra’s commitment to capture and return to captivity a number of beavers which have escaped from captivity – or have more likely been illegally released – into the River Otter in Devon for the following five reasons:

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1. Our rivers have changed dramatically

Although beavers were native to some parts of the British Isles more than 500 years ago, our rivers have changed dramatically in the past five centuries and suffer from endemic pollution, over-abstraction of water and the presence more than 20,000 weirs and dams which act as barriers to fish migration.  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 beaver dams would only increase the number of obstacles that fish have to overcome.  If we remove all these barriers to migration, then beavers present less of a problem to fisheries.

2. It would be irresponsible

In a healthy natural ecosystem, beavers can actually be beneficial because they introduce woody debris to rivers and their dams can trap silt and create new habitats.  However, fewer than 25% of England and Wales’ rivers are in good ecological condition and the Angling Trust’s view is that it would be irresponsible even to consider reintroducing this species into the wild without first restoring our rivers to good health by tackling low flows, pollution and removing the vast majority of man-made barriers to fish migration.

Beaver female/Credit: Mike Symes, Devon Wildlife Trust
Beaver female/Credit: Mike Symes, Devon Wildlife Trust

3. Beavers can spread fatal diseases

Beavers imported from abroad have the potential to spread the tapeworm Echinococcus multilocularis which can spread to dogs and humans, for whom it can be fatal.  Britain is currently free of this parasite.

4. They pose a risk to infrastructure

Evidence from North America and Germany shows the considerable risk to infrastructure – including flood defence assets, roads and railways – from allowing beavers to become established in high risk and populated areas.  An adult beaver can bring down a 10 inch wide tree in under an hour, and a single beaver family will fell up to 300 trees a year.  In the upper Danube region of Germany, beavers have caused £5 million of damage.  How will riverside residents feel when the only tree in their garden is gnawed down overnight?  Or a beaver dam floods a housing estate that has never before flooded?  The problem with beavers is that they are very secretive and mainly nocturnal, and they don’t stay put, so they will spread from rural areas to villages and the edges of towns and cities.

5. Consultation is necessary

The beavers in Devon were almost certainly released illegally by some enthusiasts who believe they can take a unilateral decision on behalf of the whole nation; there was no democratic decision taken with proper consultation with local people, businesses and landowners to seek their views.


The argument for reintroduction: Why we should reintroduce beavers to Britain’s rivers

Mark Elliott, Wetlands Project Manager at the Devon Wildlife Trust, explains why we need beavers back in Britain.

1789 was a bad year for British wetlands and wildlife. That year, the last bounty was paid for a Eurasian beaver skull in Britain. This entirely vegetarian animal, native to Europe and Asia, plays a vital role in shaping our landscape. Lost from Britain once, we need it back.

A swimming beaver
Beavers can improve the water quality of our rivers

1. Our wetland species evolved alongside beavers

Ever since the last ice age our wetland plants and animals lived in wetlands created by beavers and adapted to rely on them – look at the way trees like willow, alder and aspen regenerate when cut.  Beavers coppice trees to stimulate fresh growth, and so open out our river banks and wetlands for other species to thrive. They are remarkable water engineers and create an amazing mosaic of dams, ponds, and canals.

2. Two thirds of all British wetland species are supported by ponds

Almost all ponds are now man-made – because all the beavers have gone. In the Devon Beaver Project site, our family of beavers have made over 10 ponds in 3 years benefitting a wonderful array of dragonflies, birds and amphibians.  The 10 clumps of frogspawn laid in 2011 increased to 370 clumps this year!

3. Our rivers and wetlands are sick

They have been drained and over-engineered to get the water off the land and out to sea as quickly as possible. We suffer floods when it rains and dry rivers during droughts, and our wetland wildlife is massively depleted. Beavers are the medicine. They reinvigorate these wetlands, and hold water back in the headwaters, reducing the risk of flooding and ensuring a more constant flow of water during drier periods – better for mayflies, dippers and fish.  And the rivers are cleaner as the dams filter out the sediment and other pollutants.

4. Natural rivers are best for fish

Across most of Europe and North America, beavers are generally considered beneficial for fish like trout, and the science appears to support this. They create braided meandering rivers, with clean and extensive spawning gravels for fish. The evidence suggests that young fish grow faster and return to sea healthier if they live in beaver ponds.  Despite this some British anglers seem concerned that re-introduced beavers will dam rivers so securely that salmon will be unable to migrate up to their spawning gravels – despite the fact that our native fish evolved alongside beavers.

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5. People want them back

Many other countries in Europe have now reintroduced beavers, driven in part by the great affection that people feel for this large charismatic plant-eating rodent.  In the Knapdale area of Scotland, one local hotelier has reported that 20% of his 2013 guests were there because of the reintroduced beavers. And we have absolutely nothing to fear. Beavers are slow to spread, and stay within a few metres of rivers and streams.  They are also easy to control and any disease risks and adverse impacts can be managed. Devon Wildlife Trust is seeking to use the small wild and breeding population now living on the River Otter as an opportunity to study these impacts in a real life lowland British landscape.