KNOWLEDGE BASE

This study compared beaver cottonwood-eating patterns and cottonwood tree distribution on two rivers in Colorado, USA: one free-flowing, the other whose flow is regulated by a man-made dam. On the latter, regulated river, cottonwood trees were both less common and more likely to be eaten by beavers. A controlled flood on the same river increased foraging because beavers could access the cottonwood saplings more easily.

In one of the most heavily-cited pieces of beaver research yet published, this article demonstrated how beavers increase biodiversity at a landscape scale in the Adirondacks, USA. By adding wetlands to the mosaic of habitats at a landscape scale, beavers increased plant species diversity in riparian zones by over 33%, the beaver-modified areas themselves contributing as much as a quarter of species.

This study examined Giardia and Cryptosporidium parasites in sewage, wildlife, and agricultural sources in a river basin in Alberta, Canada. Beavers were among the wildlife tested. Cattle had the highest concentrations of these parasites whilst beavers, along with other wildlife, had lower prevalence. The tests also revealed genetic differences in the parasites depending on the animal host. Please note, this resource is not open-access.

Some scientists had suggested that a now-extinct "giant" beaver species, Castoroides, was around the size of a modern black bear. This study stress-tested those estimates, exploring how different methods for estimating the size of extinct beavers could lead to different results. Overall, the findings showed that Castoroides was probably around 60-100 kg, quite a way off black-bear-sized... Please note, this resource is not open-access.

This text compared the cases of eight different invasive mammal species in Chilean and Argentine Patagonia, including the European hare and the North American beaver. Beavers had the lowest spread rate, at around 10km/yr, although such invasion patterns were not always linear. The authors suggested that coordinated cross-border policies were needed to manage these invasions.