KNOWLEDGE BASE

Eurasian beavers were extirpated (made locally extinct) in northern Russia but recolonised the area through introductions between the 1930s and 1950s. Both Eurasian and North American beavers now live in Finland and Russia. This text described the known distribution of both species across the region and discussed their genetic origins. The article included a map of where North American beavers can be found in the region near the Finnish border - here, the two species are competing for territory.

Wolves are natural predators of beavers in Eurasia and North America but much remains unknown about the two species' relationship. This article brought together evidence from both sides of the Atlantic. For wolves, beavers can be an easy and rewarding prey, but beavers do have their own protection mechanisms and wolves did not appear to be able to significantly reduce beaver numbers at a population level. The text highlighted that the wolf's expansion in Germany would bring them into increasing contact with beavers.

This article reports on studies of Swedish beaver ponds, and the influence they had on the processing of dissolved organic material: that is, material which contains carbon. The age of the beaver pond was very important, with differences in processing between ponds and un-dammed streams disappearing as the pond ages. Therefore, beaver ponds temporarily increase organic matter in the water, diversifying the ways that carbon gets processed in the ecosystem.

In the context of widespread re-introduction efforts, this study tried to understand why North American beavers did not settle in certain areas of the USA. They found that typical cattle grazing disrupts the relationship between beavers and willow trees. By grazing, cattle make stretches of rivers unsuitable for beaver. Livestock management will have to change for successful beaver restoration in these areas. Please note, this resource is not open-access.

Published in 2016, at the time of writing the two wild populations of beavers in Scotland were present on a trial basis with the case of their full reintroduction is being considered by Scottish ministers. This review investigated the mechanisms by which beavers act as ecosystem engineers and discussed the possible impacts of beavers on the biodiversity of Scotland. The review states that a widespread positive influence on biodiversity would be expected, though detrimental impacts on certain woodland habitats and species of conservation importance is to be considered.