FOLLOWING my article on the impact of beavers on trees (Forestry Journal 310) I should like to respond to the letters from Messrs Chris Jones, Tony Fish and in particular Mr J Caley of Shouldham, Norfolk. My desire is that we learn from the mistakes of the past and do not repeat them going forward, so I would like to raise the following points:

1) Tree loss: Each beaver can cut down up to 200 trees annually for food and dam construction, and will damage more trees they do not fell. Beavers select slow-growing species like oak as well as beneficially coppicing fast-growing species like willow. In the UK, our rivers often run through farmland with few trees lining the banks – tree loss here is unsustainable. The scale of this problem can be dramatic. 50 beavers introduced into Tierra Del Fuego grew to a population of 250,000 which destroyed 35,000 ha of forest, estimated to take more than 200 years to replace. Argentina and Chile are now trying to eradicate beavers. Apart from changing the look of the traditional English landscape, fallen trees release carbon. At a time when it is government policy to grow more trees, a decision to deliberately introduce an animal that destroys trees seems incomprehensible. We are also trying not to increase the water temperature which can be done by having more trees by rivers, not less.

2) Blocking fish migration and spawning habitat: Beaver dams create obstacles to the movement of fish up and down rivers, something which is critical to the life-cycle of both migratory (salmon, sea trout) and non-migratory (e.g. brown trout) species. All fish require access to and from spawning areas. In addition, the static water held up behind beaver dams is silted, warmed, has reduced O2, and becomes unsuitable for fish spawning. This issue is doubly important because these fish species are already in decline under pressure from other environmental stresses. For this reason, it has been government policy for many years to remove obstacles to fish migration up and down river in line with the EU Water Framework Directive. How could it be wise to reverse this policy and deliberately introduce more obstacles in the form of beaver dams?

3) Costs of beaver management: Managing beaver issues will require considerable time and resources, with a high financial cost. Significant effort is required to defend trees with protective wire or sand paint, and/or to manage dams which cause flooding, etc. If such work is not fully funded, the environmental destruction caused by beavers just gets worse – as it has elsewhere in the world. It is clear that free-ranging beavers would require very significant management. Who is going to do this work and who is going to pay for it? The ROBT proposed the government should foot this very significant financial bill, which means we taxpayers of course! I suggest that if such money is available, it would be better spent on looking after our existing wildlife and not on something new.

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4) Lack of evidence: Public debate on beavers has been unbalanced by the exposure the pro-beaver lobby has been given by the BBC and other national media. At the same time, the short timescale and limited studies of the ROBT has not provided much evidence for the claimed environmental benefits, nor did it fully examine the harm beavers may do. Previous introductions, like those of the mink, grey squirrel, coypu and signal crayfish, have often proved disastrous. In the case of mink and coypu, significant resources have had to be deployed in their removal. It has been argued that beavers are just returning to their natural habitat, having been hunted out of the UK about 400 years ago. But of course, they would not be returning to anything like the same environment, and their impact on today’s much more intensively managed and densely populated landscape should not be underestimated. Without hard evidence about the actual impact a free-ranging population of beavers will have over time, a precautionary approach should be applied and no decision on their general introduction is justified.

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5) Local impacts: Beavers will eventually spread right across the country, occupying every river and watercourse. This will bring threats to local economic interests (such as farmland, plantations, fisheries) and to environmentally sensitive areas (such as the unique ecosystems of chalk streams and SSSIs). As has been said elsewhere, those who like the idea of beaver introductions are not those that will have to bear the costs or earn their living from the farmland or rivers that could be affected.

Yours sincerely,

Charles Dutton, FICFor