KNOWLEDGE BASE

The types of trees beavers use for building lodges on the Loire River, France, are not well understood. Here, scientists studied which trees beavers use and how they cut them. Beavers prefer larger willow branches for the frame of their lodges, even if these trees aren't common in the area. They then use smaller branches from various other nearby trees to cover the lodge. Beavers often cut trees so that they fall into the water and are easier to transport. Please note, this resource is not open-access.

Tool use is rare in rodents and had never been linked to aggressive displays. This article reports on observations of 'stick display behaviour' in Eurasian beavers, where the beavers held a tool (most often a stick) in their mouth and waved it up and down, sometimes splashing the water. The article contains a video of the behaviour in the Electronic Supplementary Material section. This behaviour was mainly seen at territory borders, between rivals, and triggered increased aggression in the other. It likely serves as a territorial display.

This letter presents some of the challenges associated with beaver reintroductions. It highlights concerns with the Scottish reintroduction which included the lack of an exit plan if things go wrong as beavers can't be lethally dealt with. It specifically mentions Baltic countries' experiences, which warn of overpopulation leading to impacts on smallholders through flooding and loss of land.

Elk can damage plant populations by over-eating. Fences to protect certain areas work by excluding other animals but the exclusion of all mammals may not always be needed to allow plants to recover. This article reports on a new fence design which excludes elk but allows access for other species like deer and beavers. The new fence was successful, keeping out elk (and cattle) but allowing access for other mammals including beavers. Aspen trees protected by this fence ended up growing taller over a 2-year period.

This text describes how landslides - often overlooked - have an important role in maintaining biodiversity. Landslides create completely new landscapes and soil conditions. They can interact with other disturbances like fire and avalanches. Animals like beavers often colonise landslide areas, using the debris and new landscape to build dams and and increase habitat diversity.