KNOWLEDGE BASE

This study examines how North American beaver abundance varies across their range in Québec, Canada, and predicts their response to climate change. Today, beavers live at high density in the south and decrease northward. By 2055, beaver density is predicted to increase more in their current range than at the northern edge. Most monitoring efforts are focussed at the range edge, in areas where beavers may disperse into. This study shows that some of the most significant climate impacts - an increase in abundance within their current range - may be being overlooked.

Prior to the Scottish Beaver Trial (approved in 2008), another reintroduction proposal was rejected because of the risk to tree conservation. This study tests that case by examining two years of willow and aspen regrowth after beavers had felled them in Scotland. The results showed that both species regenerated very quickly and that tree conservation would not be threatened by a well-managed reintroduction of beavers. The text goes into more detail on tree regrowth patterns, for example showing how willow regrowth in inundated areas avoided foraging by both beavers and deer.

This paper sought to understand whether beavers' impacts in South America - as a non-native species - were similar to, or predictable based on, their impacts in North America. The result was, largely, yes, leading to a discussion of recommended management options for the invasive beaver in Patagonia. The authors suggested that effective management required more studies of the native ecosystems rather than the invasive beaver itself.

As ecosystem engineers, beavers play a crucial role in facilitating environments - in other words, making them more suitable - for other species. This Finnish study on the relationship between beavers and teal ducks spanned over a decade. It found that beaver ponds provided more resources (more food) and better habitat structure (bigger ponds, shallower water) for ducklings. This enabled a higher brood density and lower mortality compared to areas without beaver activity. Please note, this resource is not open-access.

This article summarises the preparatory work that had been undertaken for reintroducing beavers to Britain. Specifically, the feasibility and public desirability of such an initiative are described, as well as beavers' ecological and public health impacts. Potential management issues are highlighted in the article and Scotland's trial at Knapdale (2009) is said to be important in exploring these issues further.