The history of beavers in Britain, beaver genetics and reintroductions

Three recent papers published in the scientific press contribute to the debate about important issues surrounding beavers in Britain and their reintroduction. The first by Adrian Manning and colleagues (Manning, Coles, Lunn et al. 2014) reports on the use of radiocarbon dating techniques to date a wood specimen with beaver gnaw marks from Kielder Forest in the North of England to the 14th century AD. The authors say that this is, “the most recent radiocarbon-dated physical evidence of beaver yet found in Britain, by at least 400 years”. They go on to highlight the importance of not ignoring possible beaver signs when discovered and that this find strengthens the case for beaver reintroduction and restoration of riparian woodlands in the uplands. The other two papers by Helen Senn and co-workers (Senn, Ogden, Frosch et al. 2014) and Susanne Horn and co-workers (Horn, Prost, Stiller et al. 2014) concern the past and present genetic structure of Eurasian beaver populations. Susanne Horn reports that surviving relict populations of beavers are characterised by low genetic diversity and a strong phylogenetic structure (the relationship between evolutionary groups within the species). Helen Senn considers the nuclear and mitochondrial genetic structure in the Eurasian beaver from possible source populations for reintroductions to Scotland and the merits of the two approaches that are frequently of concern in reintroduction studies: to reintroduce beavers that (genetically) most closely resemble the animals that were historically present in the target area before they went extinct or to pick animals with low levels of inbreeding and high combined genetic diversity. The authors’ consideration of these two positions is detailed and interesting. They conclude, ” All else being equal, using a genetically diverse founder stock of a large number of animals, that is, monitored for inbreeding following release, represents the lowest risk genetic strategy for ensuring the long-term survival of the reintroduction”.

The full references can be found on the Bibliography page.

Posted on October 2, 2014 at 1:11 pm

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