KNOWLEDGE BASE

In this study, researchers tried to understand how willow trees grow on different landforms found in the rivers of the Rocky Mountains, USA. They compared historic willow growth to river levels on landforms including former beaver ponds. Moments of flooding were shown to be important in the cycle of willow growth, including after breaches of beaver dams. They explain three different ways in which climate change will make life harder for willows but describe how the return of beavers may mitigate some of these challenges. Please note, this resource is not open-access.

This study investigated whether abandoned beaver dams had long-term effects on the types of plants found in Argentinean forests. They found that beavers altered both the quantity, species, and extent of plant species. Ferns were most affected, while grasses thrived. Trees did not recover quickly. This suggests that these forests may be struggling to adapt to the sustained presence of beavers. The population levels of beavers in this area is not sustainable for the ecosystem.

Since their introduction to southern South America in 1946, North American beavers have rapidly expanded their populations. This study sought to understand what impact North American beavers had on plant populations in Chile and compare this to their impact in North America. In Chile, beavers significantly reduced forest canopy, altered tree seedling composition, and increased the quantity of plant biomass. So far, similar to at home. However, unlike in North America, their presence enabled invasive plant species to dominate, endangering the balance of the ecosystem.

This study tested how territorial beavers react to intruders of different ages, by using scent extracts (castoreum) from different beavers. Contrary to expectations, beavers did not respond differently to the size or age of the intruder. This suggests beavers may not be able to tell the age of intruding beavers based on scent alone and may rely on matching the scent to the intruder if ever they meet.

This study created a model to identify suitable habitats for beavers in Salzburg, Austria. The existing beaver distribution in the area indicated that the population hadn't reached its full capacity yet. The model identified 13 regions large enough to host colonies and predicted a 72% increase in beaver populations. Management strategies for potential conflicts between beavers and humans are suggested.