From the June, 2020, DNR Dam Safety Newsletter (email):
History and Management: Although beaver seem abundant today, due to fur trapping and logging efforts, some estimates suggest that by the late 1800’s there were only 500 beaver left in Wisconsin. However, trapping of nuisance beaver in Northern Wisconsin followed by relocation efforts caused the beaver population to rebound and eventually led to a thriving population. Demand for beaver fur decreased in the 1980’s leading to reduced trapping efforts. In the late 1980’s legislation was enacted to allow trapping or hunting of beavers year-round without a license or permit if damages were incurred on a landowner’s property. Federal, tribal, state and local governments have developed management plans to effectively manage numbers and the benefits and impacts.
Beaver have teeth that never stop growing. They have transparent eyelids. They can stay under water for up to 15 minutes. Beavers build homes with multiple rooms for various activities. Beavers are the largest rodent in North America weighing between 35 and 50 pounds.
Ecosystem and Economic Impacts: The single most common feature of beaver habitat is the presence of water. For security and access to food, beavers engineer the environment around them by building dams to increase flooded depths and expand wetland areas typically on small- and medium-sized low gradient streams, wetlands and lakes. Beaver activities often benefit wildlife and improve ecosystem habitat (for example, reducing peak discharge, decreasing sedimentation downstream, increasing summer stream baseflow and increasing habitat diversity). However, beaver activity can also damage and reduce flows through hydraulic structures such as road crossings or dams.
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