KNOWLEDGE BASE

In Alberta, Canada, flow devices were used to prevent flooding by beavers (a pipe which allows water to drain through the dam). Traditional methods of managing such flooding may have included killing the beavers. The costs and benefits of these options - over a period of three years and at a province-wide scale - are presented in this study, finding that the flow device was cost-effective in comparison to traditional management methods.

Researchers examined how food availability affects the reproductive behavior and physical condition of wild Eurasian beavers over their lifetimes. Drawing on 15 years of data, they found that beavers never stop putting on weight, but that this slows down with age. Rainier years negatively impacted reproduction for all ages of beaver. Beavers living in territories with less food experienced reproductive decline (were less likely to reproduce) more quickly than those in good territories. The text describes other dynamics connecting food availability, ageing and reproduction.

This text reported on the Eurasian beaver population in the Republic of Mordovia, an area at the centre of European Russia. The article showed the varying population densities in large, medium, and small rivers across the region. In 2016, the total beaver population in the area was approximately 17,000 individuals, increasing from the total of 34 individuals originally reintroduced around 80 years beforehand.

Researchers tracked beavers' movements to understand which beavers went outside their territories on 'forays,' and how often. Both breeding and non-breeding beavers conduct forays, spending up to 11% of their active time on these trips. Forays were energetically costly, suggesting they might help assess resources or potential mates. Non-breeding beavers conducted more forays, possibly to gather information before leaving home.

This study brought together over 150 studies to compare beaver dams to artificial dams - specifically considering their impacts on biodiversity, hydrology, and biochemistry. Overall, beaver dams positively impact aquatic environments, with many effects varying by pond age. Some of these effects were similar to those of artifical dams, but some were not - for example, artifical dams may lead to greater nutrient retention in the pond.