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.Charles P. ForbesJuly 16, 2020
Major ReferencesAvery, Ed. Bibliogrpahy of Beaver, Trout, Wildlife, and Forest Relationships. [Technical Bulletin No. 137] Madison, 1983. View Full EntryBartlett, Des and Jen. Nature's Aquatic Engineers: Beavers. [National Geographic, May 1974 p.716] Washington, 1974. View Full EntryBates, John. River Life [Manitowish River]. Mercer, 2001. View Full EntryClark, James. Wisconsin: Land of Frenchmen, Indians, and the Beaver. [Chronicles of Wisconsin] Madison, 1955. View Full EntryDoyle, Mary Ann. Sacred Center: How Beavers Shape Their Environments.. [Living on the Lake, July 2012, pp. 11-15.] Rhinelander, 2012. View Full EntryJackson, H. H. T.. Mammals of Wisconsin. Madison, 1961. View Full EntryKnudsen, George. History of Beaver in Wisconsin. [Misc. Research Report No. 7 (Game)] Madison, 1963. View Full EntryKnudsen, George. Relationship of Beaver to Forest, Trout and Wildlife in Wisconsin. [Tech. Bull. No. 25] Madison, 1962. View Full EntryKrech, Shepard. Ecological Indian, Myth and History. NY, 1999. View Full EntryLaycock, George. Nature's Compulsive Engineers: Beaver. [GEO, V.5 June 1983 p.60] Los Angeles, 1983. View Full EntryOhio Division of Wildlife. Beaver. [Life History Notes, Publication 97] Columbus, 1999. View Full Entry (Full text available)Pils, Charles. Beaver. [PUBL-WM-059 83] Madison, 1983. View Full EntrySanderson, Ivan. Living Mammals of the World. Garden City, New York, 1955. View Full Entry