The Beaver

This is the first of a new series of articles on the role of reintroductions and translocations as a tool in wildlife conservation. Sadly, many species have been lost from the UK and aiding the restoration of those that are part of the Caledonian Forest is a key part of our long-term vision.


Beavers are semi-aquatic mammals. They are the largest native European rodent and measure up to a metre in length. They have a long, flattened tail which they use as a rudder and webbed feet that are used for propulsion. Beavers generally inhabit lowland riparian woodland bordering slow-moving streams or ponds. They live in lodges which they construct from tree branches and sticks, and they build dams to control water movement. They are completely vegetarian and eat both the lush green parts and the woody stems and trunks of trees, as well as a variety of rushes and sedges. They live in family groups and produce kits (young) every year.

Why should beavers be reintroduced?

The European beaver (Castor fiber) was present in the UK until the 16th century, when it was hunted to extinction for its pelts, meat and musk oil. From the early 1990s onwards, there was a growing movement to see the species reintroduced. This led to the 5 year Scottish Beaver Trial in Argyll, which ran from 2009 to 2014. Subsequent to that, the Scottish Government announced in November 2016 that beavers were officially recognised as a native species and that the populations in Argyll and Tayside could continue live to free in the country.

We are legally obliged by European directives to consider the reintroduction of the beaver and, at Trees for Life, we believe that we also have an ethical obligation to reintroduce the species, given that we caused its extinction. There are also likely to be significant benefits from tourism and estimates have shown that beavers could bring in £2 million a year in revenue.

However, the main reason that we believe beavers should be reintroduced is due to their role as ecosystem engineers. Beavers are a keystone species, meaning that they play a critical role in maintaining the ecological community of which they are a part. They coppice and fell trees, opening up the canopy and letting light into the forest, enabling other species to grow. By damming water courses they create new areas of wetland which attract other species and they also improve water quality and reduce siltation. Together, these factors lead to a huge increase in species diversity.

Concerns about beaver reintroduction

A number of concerns have been expressed regarding beaver reintroduction, but many of these are inaccurate or unfounded.

  • Myth, Beavers will damage the salmon industry
    • Beavers are entirely vegetarian and do not eat fish. Concern has been expressed that they will dam rivers and prevent salmon getting upstream to spawn. However, records show that this is relatively rare and that such obstructions are short-lived. Usually, salmon are easily able to negotiate beaver dams and the two species have existed together for centuries in many European countries. In Norway, where beaver and salmon populations have increased side by side over a 40 year period, beavers have actually been shown to benefit the salmon industry. They oxygenate the water and, through damming, create additional pools that are ideal for spawning.
  • Myth, Beavers will damage forestry operations
    • Beavers prefer broadleaved trees and so should have a limited adverse impact on commercial forestry. Concern has been expressed that they may damage native aspen and willow stands (their favourite food). Both aspen and willow quickly send out new shoots in response to beaver impacts and beavers seem to avoid this young regrowth, giving the trees time to regenerate. Where regrowth is susceptible to deer damage it can be protected using tree guards or fencing. 
  • Myth, Beavers will eat crops and destroy farmland
    • Beavers do sometimes feed on crops such as maize and sugar beet, but this is usually small-scale and localised. Crop damage can be minimised by leaving a buffer strip alongside water courses. There are a range of options for dealing with beaver constructions that lead to flooding of farmland. 

The history of beaver reintroduction

Beavers were extirpated from much of their former range but have been reintroduced to 24 European countries, with Sweden leading the way as long ago as 1922. Until the Scottish Government decision of November 2016, the UK was one of only seven countries that had not reintroduced the species. In England, a beaver trial has been underway in Devon since 2011, and Wales is also actively considering the reintroduction of beavers.

The beavers from the official beaver trial are still living at Knapdale in Argyll, but the population there is isolated and unable to spread, so it needs to be augmented with additional animals, to ensure that there is enough genetic viability for it to continue to thrive. The other population of beavers living wild in Scotland is in the catchment of the River Tay, and is the result of several generations of breeding by beavers that escaped from captivity. Estimates of the numbers there vary from 150 to more than 250 animals, and the population is continuing to increase its geographic range. 

Trees for Life’s position on beavers

We strongly support a wider-scale reintroduction of beavers to Scotland, as we believe that they are integral to the health of our rivers and are a crucial part of the Caledonian Forest ecosystem. If left to themselves, beavers would take a long time to disperse from the existing populations in Argyll and Tayside to reach, for example, the northwestern Highlands and many of the areas where we work. In addition, the genetic base of the two existing populations is very narrow, as both come from small groups of founder animals, so further reintroductions are required to broaden the genetic base of the species in Scotland. For all of these reasons we are currently doing the preparatory work for an application to reintroduce beavers to the Highlands.

Becky Priestley



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