Written by Dr. Carrie DeJaco
Prior to European colonization of North America, beaver (Castor canadensis) were abundant throughout most of the continent. Estimates of pre-colonization beaver populations are between 60 million and 200 million individuals, with at least 20 million beaver-built dams. By the year 1900, beaver had been extirpated from the eastern half of North America and the species was hanging on by small remnant populations in the west.
Reintroductions of beaver had begun in the southeastern U.S. by the 1940s. With few predators and laws regulating hunting, beaver populations in North American have rebounded. By 1983, beaver were present in 80 of 100 counties in North Carolina but were still largely absent from the Broad, French Broad, Catawba, and Pasquotank river basins—mainly the Charlotte area and the region directly to the west and north of it.
The majority of studies on beaver in North America have been conducted in the northern states and Canada. Larger scale effects found by these studies may be applicable here in the south, but many of the species-specific observations are irrelevant due to the difference in plant species between the northern and southern latitudes. This review of the literature on the impacts of beaver includes the handful of studies conducted in the southeastern U.S.; larger scale patterns observed at northern latitudes will also be discussed, but species-level observations from northern studies will only be included if they are relevant to the southeastern U.S..
Beaver Lodge (Franklin County, NC) Photo by Alvin Braswell