More than 150 beavers living in the River Tay and Earn catchments have been found to be well adapted to living in Scotland; are Eurasian beavers once native to Britain; and are free of diseases of concern to humans, domestic animals and other wildlife, according to three reports published by Scottish Natural Heritage (SNH) on behalf of the Tayside Beaver Study Group.
Beaver (Photo: Paul Stevenson)
Impacts on various land use interests are also documented together with the results of trials of various techniques for managing the effect of beavers, and a series of conclusions on the likely implications if beavers remain in Scotland.
The beavers have been in Tayside since at least 2006, and are thought to originate either from escapes or illegal releases from private collections. They have been found in rivers and lochs stretching from Kinloch Rannoch, Kenmore and Crieff in the west to Forfar, Perth and Bridge of Earn in the east.
In March 2012, Scotland’s Minister for Environment, Stewart Stevenson, opted to allow the Tayside beavers to remain in the wild for the duration of the official trial reintroduction of beavers in Knapdale, Argyll. At his request, the Tayside Beaver Study Group was set up to gather information and monitor their impacts on land uses and find out more about how to manage them. The findings, along with those from the Knapdale trial and other research, will help Scottish Ministers decide later this year whether or not to permanently reintroduce beavers to Scotland.
The final report on the work of the Tayside Beaver Study Group shows the beavers are well adapted to living in Scotland. They are successfully producing young and still spreading through the Tayside catchment. The group made an early decision not to repeat ecological studies carried out in Knapdale, but to focus resources on documenting the interactions between the beavers and the wider range of land management interests in Tayside. They found fewer concerns about beavers in less intensively managed areas.
The most significant impacts were in areas important for agricultural production, especially in the intensively cultivated arable ground on the flood plain of the lower River Isla where it meets the River Tay. Any beaver dams left in place here could cause the extensive network of drainage ditches to fail, causing flooding and interfering with cultivation of productive land. Beaver burrows in earth flood banks also increased the risk of a breach and flooding of the farm land behind.
A number of methods to protect trees from being gnawed and felled and to reduce water levels behind dams were trialled successfully. The impacts of burrowing in flood banks and regular damming of drainage networks were more challenging to manage. Mitigation of these issues was not possible during the study, but would need to be addressed effectively if beavers were to remain. Of those people experiencing negative impacts, 70% stated a financial cost as a consequence.
A second report on tests on 21 beavers from across the catchment found they were all healthy and free from any parasites or diseases of concern to humans, domestic animals and other wildlife.
Genetic tests on a further sample of 25 beavers, documented in the third report, show them to be Eurasian rather than North American beavers, and of German (most likely Bavarian) origin. They were from three family lines, providing adequate genetic diversity for the short-term. There could, however, be a need for genetic monitoring and management in the future if beavers were fully reintroduced to Scotland.
David Bale, Chair of the Tayside Beaver Study Group and SNH’s Area Manager for Tayside & Grampian, said: “These are very useful findings. They show there is no evident risk of diseases being transmitted from the Tayside beavers to other animals, or indeed to humans. The genetic tests tell us that they would be suitable for permanent reintroduction to Scotland, because they are Eurasian rather than North American beavers. They are also varied enough genetically to make a reasonable first step towards a full reintroduction if that was the decision of the Scottish Government.
“Our work documenting the impacts of beavers on land management interests has shown that in many situations, beavers are likely to cause few concerns. But if they were to be permanently reintroduced, efficient, effective and affordable ways of managing and reducing potentially significant impacts on intensively farmed land and other interests would have to be found.
“I am grateful to the members of the Tayside Beaver Study Group for working so well together to produce these reports. They will go to the Scottish Government along with other beaver studies in late May, so the decision on the future of beavers in Scotland is based on the best information available.”