KNOWLEDGE BASE

North American beavers and brown trout do not live in the same places naturally, but both are invasive species in Chile. This study explored their interactions, finding that beavers supported trout growth by providing more food, and more diverse food at that.

Eurasian beaver populations were reduced to ~1,200 animals, but have recovered through reintroductions and natural spread, now reaching around 1.5 million. Range expansion has been rapid, with beavers re-established in most of their former European range and parts of Siberia. Genetic studies have shown two surviving clades. Future increases in populations and impacts on freshwater systems are expected and the researchers state that beaver management should be integrated into densely populated regions.

This study explored beavers' food preferences in northern Poland, focusing on plant species, stem size, and human disturbance. Beavers preferred willows, maples, and alders, particularly those with stems under 10 cm. Human disturbance - or anthropopression - influenced their foraging behaviour, confirming patterns observed in previous research on beaver diets.

In Norway, scientists studied Eurasian beaver pairs to understand how close they stuck together as they went about their business. This was based on GPS data from 14 pairs. The results showed they don't spend much time together, staying (on average) around 500 m apart. They stayed further apart when they were occupying a larger territory. The scientists proposed that, because beavers are monogamous, they focus more on defending their territory than they do their partner.

This paper compares how environmental factors (such as climate, food availability, human disturbance) influence the distribution of native Eurasian beavers and invasive North American beavers in Finland. Both had similar preferences for rivers, streams, and lakes. There are some differences between the species in the trees they preferred. The authors suspect, however, that much of the difference in habitat is due to the populations' histories i.e. they currently exist near to the places where they were successfully reintroduced.