Castor fiber by Aivar Ruukel in Soomaa National Park Estonia
From 1 May 2019 European beaver (Castor fiber) will be added to the list of European Protected Species of Animals, protected under Scottish law, making it an offence to kill, injure or capture them.
The long-awaited and controversial move comes after protracted debate in Scotland about how their numbers should be managed. According to Scottish Natural Heritage (SNH), the beaver population has tripled in Scotland over the past six years to 430 beavers in more than 100 active territories on Tayside. Scottish farmers have raised concerns about the damage caused to agricultural land from their dam-building.
In February SNH published Interim Beaver Management Advice, recognising that in some places and situations the activities of beavers can have negative impacts on other interests such as farms, gardens, or other land. SNH has stated that sometimes this can be easily managed to prevent damage, such as by fencing vulnerable areas or protecting individual trees, and in others there is the potential for more novel techniques, such as beaver dam ‘deceivers’. SNH is currently providing free and expert advice to help people experiencing problems and where possible to provide measures to minimise damage through a beaver mitigation scheme.
Meanwhile in Essex, European beaver have been released in a fenced enclosure covering four hectares of woodland on the Spains Hall estate in Finchingfield, near Braintree as part of natural flood management trials being part funded by the Environment Agency and Anglian Eastern RFCC.
A formerly native species, the return of European beaver to the UK after an absence of ~500 years is welcomed by many. Their ability to create wetland habitat through dam building has been cited as a potential benefit to reducing flood risk and improving water quality and ecology in the right circumstances. The European beaver builds fewer dams than its North American cousin, and it does so generally in streams to maintain water levels above the entrance to its burrow. Dams are built of tree trunks, branches and mud, and are about one metre in height and rarely longer than fifteen metres. They are usually breached by flood waters each year. However, Beavers and flood and water management unlike its North American cousin it prefers to dig burrows in riverbanks in which to nest rather than building lodges of piled logs. The entrance to the burrow is typically below the waterline, with the nest chambers typically 0.4-0.5 metres in height positioned 0.3-0.7 metres above the burrow entrance. (See Natural England: The feasibility and acceptability of reintroducing the European beaver to England 2009 [pdf])
However, this activity can also cause damage and thus endanger safety, especially in lowland areas, such as by undermining flood defences and watercourse embankments, or collapsed dams lodging in culverts and ditches. Water managers will need to find measures to make critical areas and infrastructure less attractive to beavers and mitigate their damage. This means having a regulatory system and resources in place that enables flood Risk Management Authorities to take proportionate measures swiftly where they cause damage and thereby endanger safety. ADA is following with interest research in this area by colleagues in the Netherlands, who already face the risk from these large rodents undermining their dikes. With a better understanding of the behaviour of beavers in the field, the Dutch Union of Water Boards hope to make it easier to detect excavation damage, and possible to ‘steer’ them in such a way that damage to flood defences can be prevented.