BACE

Scotland’s Environment Minister, Stewart Stevenson, announced on the 16th March 2012 that a decision on the fate of the wild beavers living on the River Tay, Scotland will be postponed until 2015 when the official beaver release trial at Knapdale in Argyl is due to end. In the interim, a group chaired by Scottish Natural Heritage (SNH) will monitor the beavers and advise local landowners on how to manage their presence. It is thought that there may be as many as 100 beavers or more now living on the Tay.  The announcement overturns the previous decision to live trap and remove the animals and has been widely reported in the media: The Scottish Government, BBC News, The Guardian, The Scotsman,The Telegraph, STV, Walkhighlands.

This unlikely headline was printed by the Scotsman on 14th January 2012. The ensuing article refers to a call from the Scottish Gamekeepers Association to the Scottish Government, ” to carry out further research on the beavers, which are classed as an illegal species, before deciding whether they should be allowed to remain in the wild.” It is true that research on the short-term and the long-term effects of beavers is required, not only to avoid such rhetoric, but also to fully understand the ecosystem services that many believe beavers will bring both to the local community and further afield. Stewart Stevenson, the  Environment Minister in the Scottish Government, is  believed to be making a statement about the fate of the Tay beavers sometime soon.

Two new papers have been published in Mammal Review this month (see Bibliography page for citations) which are interesting with respect to beavers in Britain. The first by Maeva Dewas and colleagues looks at the history of expansion and current status of beavers in France. The paper is illustrated by some excellent maps. The reestablishment of beavers on French river systems is considered a success with most river systems holding beavers and with numbers increasing. Throughout much of France, beavers have naturally recolonised or been introduced from the relict Rhone population, thus maintaining their genetic integrity. However, since 2000 beavers of different geographic origins have been spreading into the north and north-east of France from neighbouring countries which is likely to lead to introgressive hybridisation between the different forms, at least in these contact areas. The authors raise the intriguing question as what management strategies should be adopted in the future, if any, to prevent further mixing of beaver populations. In general, relict beaver populations show low genetic diversity, but populations of mixed origin, such as those in Bavaria, may be genetically more diverse and better equipped to adapt to environmental changes. However, much more research is needed on this topic. Equally if more not more important in the short-term is the discovery of North American beavers in Germany, as well as being present in Luxembourg and Belgium. North American beavers outcome Eurasian beavers and steps have been recently initiated to eradicate the alien species.

The need for more genetic data is taken up in the second paper published in Mammal Review by Frank Rosell and colleagues. It  furthers the consideration about sourcing Eurasian beavers for reintroductions into Britain made by Duncan Halley (2011 – see Bibliography page). Of Halley’s three options for sourcing reintroductions, the first (using mixed stock from eastern and western European evolutionary significant units, ESU, i.e. populations considered to be distinct for conservation management) is dismissed by Rosell et al. because in contravenes IUCN guidelines. They go on and state that further research is required concerning Halley’s other two options, to use beavers from a single or mixed western ESU populations, and that considerations of practicality or money should not enter the equation.

The relationship between beavers and fish has been much debated and is a key issue to be considered in reintroduction proposals within Britain. Following their review of this topic for Scottish Natural Heritage (2010), Paul Kemp and colleagues have just published a paper based on this report in the journal Fish and Fisheries (online publication at present – see Bibliography page for full citation). The abstract reads, Reintroduction of beaver (Castor spp) may facilitate rehabilitation of freshwater habitats providing a cost-effective sustainable means of improving ecological conditions. Despite extensive research, debate and consultation, a general consensus on the impact of beaver on fishes has proven elusive because of variability in biological response. This paper provides a systematic review of the impacts of beaver dams on fishes and fish habitat based on a meta-analysis of the literature and expert opinion. Research is regionally biased to North America (88%). The most frequently cited benefits of beaver dams were increased habitat heterogeneity, rearing and overwintering habitat and flow refuge, and invertebrate production. Impeded fish movement because of dams, siltation of spawning habitat and low oxygen levels in ponds were the most often cited negative impacts. Benefits (184) were cited more frequently than costs (119). Impacts were spatially and temporally variable and differed with species. The majority of 49 North American and European experts considered beaver to have an overall positive impact on fish populations, through their influence on abundance and productivity. Perceived negative effects related to the movement of aquatic organisms in tributary streams, including upstream and downstream migrating salmonids, and the availability of suitable spawning habitat.

Richard Taylor-Jones, producer for the Springwatch Adventure Team,  asks what you think about the reintroduction of beavers to the UK. Visit Richard’s blog and add your comments. In the BBC Wildlife Magazine, Chris Packham was asked, What species, if any, do you think should be reintroduced to Britain? Chris’ reply was, Beaver. Properly and NOW! It’s a disgrace that this rodent is not fully at large in the UK. It shows how we have not really got conservation into top gear at the moment.

As reported on the Devon Wildlife Trust’s website and in the Shooting Times, the Devon WildlifeTrust has moved two beavers to a secure location in the north of the county, as part of a three-year experiment to restore a rare wetland habitat. The Trust says that the animals have settled well into their new home, a 2.8 hectare Culm grassland and wet woodland site in private ownership. Conservation manager Peter Burgess said: It is excellent to have the pair of beavers on site. Though not a release into the wild like the trial being carried out in Scotland, we hope studying these creatures over the next few years will yield insights into the impact on one of our most treasure wetland habitats.