KNOWLEDGE BASE

Researchers studied the genetic makeup of two introduced beaver populations from different regions in Russia. The researchers studied five specific points in the beavers' DNA. They found differences which were explained by the populations' history, interbreeding, and initial migration. Please note, this resource is not open-source.

This study tested ecological population theories on a beaver population in a Canadian protected area, monitored over 11 years. In that time, the overall population declined steadily. The paper explored the interactions of breeding, dispersal, habitat suitability, and plant availability. It noted that, without the large-scale disturbances of forest fires (which are aggressively suppressed in the area), beaver foraging may lead to a steady decline in the quality of the beaver's own habitat.

In this study, researchers explored how man-made dams, which regulate the flow of a river, affect beaver populations. To do so, they compared two rivers - one free-flowing, and the other regulated. They found that, in this case, beavers benefitted from flow regulation. The regulated river had more islands which allowed the river to support willow trees for beavers to eat. The beavers on the regulated river lived at a higher population density and had larger body sizes.

Beavers, both Eurasian and North American, require water deep enough for their lodges and food caches. They often build dams on smaller streams to create ponds. These dams transform ecosystems, affecting water conditions and species diversity. This review described the impacts that such activities have on different fish species - creating new habitat conditions, changing others, and at times blocking fish migration. The text described these impacts in detail, noting how the impact of beaver reintroductions on fish will vary depending on the specific location.

How quick is evolution? Scientists compared the hatching rates and temperature tolerance of wood frog's eggs sourced from three forested wetlands and three more formerly forested wetlands where beavers had been present and shaping the ecosystem for 36 years. It found that the eggs from beaver-shaped wetlands hatched more slowly and could withstand higher temperatures. These differences suggested rapid evolutionary divergence, potentially driven by the beavers' landscape transformations. The speed of this divergence had implications for our ecological understanding of climate change and deforestation.