KNOWLEDGE BASE

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.

In Mongolia in 2015, extreme frosts caused beavers to become trapped in their lodge, preventing access to food. Local people released five trapped beavers, and all had freshly-gnawed tails. Without large terrestrial predators in the area, it's likely that the beavers gnawed their own tails. This text reported on this case and discussed the possible reasoning for it, suggesting it was likely a response to extreme stress.

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.