Trial re-introduction of the Eurasian beaver after an absence of 400 years to Scotland, UK

Summary

The Eurasian beaver (Castor fiber), extinct in Scotland since the 16th century though now Least Concern globally following recovery and reintroduction across more than 24 European countries, was reintroduced to Knapdale Forest in mid-Argyll under the Scottish Beaver Trial, a scientifically monitored, time-limited pilot designed to inform a Scottish government decision on the species' future in the country. The Royal Zoological Society of Scotland and Scottish Wildlife Trust, working with Scottish Natural Heritage, built Britain's first species-reintroduction licence application from scratch, securing a May 2008 licence with 31 conditions covering animal welfare, monitoring, and mitigation, after which 16 beavers sourced from Norway were released as family units into individual lochs across 2009-2010. A five-year, multi-disciplinary monitoring program involving 13 independent scientific partners tracked beaver ecology and health, freshwater and woodland habitat, fish communities, water chemistry, archaeology and local socio-economic impacts, using methods from GPS field-sign mapping and camera trapping to blood sampling and business surveys, informed by pre-release baseline surveys. Difficulties included project costs and ongoing fundraising needs, mortality and dispersal of animals in quarantine, uncertainty over the long-term viability of such a small founder population, and an unrelated unofficial beaver release elsewhere in eastern Scotland. The project rates itself successful, citing its status as a milestone first official UK mammal reintroduction, robust multi-partner scientific delivery, majority public support and strong media and education engagement, flexible adaptive management of animal handling techniques, and clear evidence that Eurasian beavers can survive and establish in the Scottish environment.