I'll be Dammed!

As an ecosystem engineer, the Eurasian beaver (Castor fiber) quickly dominates and changes landscapes. Over 400 years after their disappearance from the British countryside they’re back.

European Beaver - https://commons.wikimedia.org/wiki/File:Beaver_pho34.jpg - Per Harald Olsen

The mysterious reappearance of the locally extinct Eurasian beaver to the river Otter in East Devon back in 2013, whilst overjoying and bewildering British naturalists, proved contentious with policymakers and local agriculturalists. Keystone species (previously explored in Reframing Keystone Species by Sam Hubble) are those with elevated importance in an ecosystem as a result of their role within that ecosystem. Beavers create new wetlands and ponds through the felling of trees and creation of dams, reshaping the landscape in ways that facilitate ecosystem level changes, and are as such considered a keystone species.

It doesn't require much imagination to understand how the British countryside would have changed with four hundred years of beaver absence. Nor does it take much to imagine the damage beavers could do to this countryside that has built up in their absence in just a few years. It has now been three years since the Eurasian beaver miraculously re-emerged in Devon, England and naturalists and locals alike still have a lot to say on the matter.

The story can be summarised as follows. In 2013, although finding the exact dates are difficult due to the lack of understanding of how they were released, naturalists in Devon found gnawed trees which they believed to have been done by beavers. After a short period of monitoring it was discovered that the River Otter had recently begun to house two breeding pairs of beavers and five young, known as kits. After being trapped, removed and tested for diseases in captivity the beavers were given the all clear and scientists were able to ensure they were in fact members of the locally extinct Eurasian beaver species. Following this Natural England proposed a five year plan post re-release into the river that would enable them to monitor and record results of the trial introduction.

Nearly a year on in the trial, in May 2016, a new pair of individuals were added to the population to increase the genetic diversity within the population. The re-released population, though thriving with at least two successful litters having been discovered since their initial sighting, had undergone genetic screening which revealed that all were very closely related. In the 2016 report from the Devon Wildlife Trust, the beavers were found not to stray far from the river when felling trees and the vast majority of trees with feeding signs mapped were willow trees at the rivers edge with a very narrow (<3cm) trunk diameter. With regular monitoring and the potential for intervention from these monitoring groups it seems unlikely that the landscape will become changed in a way that endangers other native species.

European Beaver in Estonia - https://commons.wikimedia.org/wiki/File:Vee_poole_-_Za%C4%8Dek.jpg - Sven Začek

Those worried about the construction of dams on the main river can rest assured that all dams have been created in smaller streams and ditches to create deeper water which beavers use for safety. The Natural England trial comes with its conditions which include an Exit Strategy to be enforced when the significance of the effects seen in communities of local landowners is deemed unacceptable. Although this assurance that land owners will see minimal effects does not seems to have only been taken with a pinch of salt, as news outlets report that as recently as October 2016 Sir Benjamin Slade, the Woodlands Castle owner in Somerset has put a £1000 bounty on the heads of any beavers killed on his estate. He claims that beavers felling trees on his estate have migrates from the Devon trial, although experts assure that there are no signs typical of beavers anywhere on site trees.

All stakeholders involved in this trial, from Natural England and beaver enthusiasts to local landowners have every right to their say until the trial is set to end in 2020. However, as a conservationist and someone who has followed the story since it began in 2013, I cannot wait to see how the next four years pan out during the trial and hope to see more headlines announcing their re-instatement as a native species.

#beavers #reintroduction #keystonespecies #britishwilldife #rewilding

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