The Southern Appalachian Oak Communities Hypertext Encyclopedia

Beaver

The beaver, Castor canadensis, was once extirpated through fur trapping, forestry, fires, and agriculture throughout the southern Appalachians (e.g., 1911 in Virginia) but has regained high, stable populations in many areas. Protection, low fur prices reducing trapping, and transplanting of wild beavers has been responsible for the population resurgence. Fur of beavers in the southern Appalachians was not superior except in the high elevations. The animals' earthen and brush dams had major, profound influence on aquatic wildlife but also on terrestrial animals (ducks, muskrats, raccoons, mink, and woodcock and many other animals such as salamanders). Flooded swamps and forests provided many large, varied habitats for many species of birds and other animals. The beavers' behavior was responsible for rich, stair-step, soil-flats or benches forming and influencing watersheds (flooding, channel scouring, sediment loads, and groundwater recharge). It was a major, generally positive, geomorphic force. It, along with logging, and loss of its food supply interrupted this profound land-shaping influence for a hundred years. The change in groundwater decreased site quality in vast areas.

Beavers live in stream banks, in lodges of "nests" of collected wood, or in dams. They feed primarily of woody stem cambium. Family units live in these lodges but young leave when 2-years old, typically moving to upstream areas. Gestation is 4 months long after breeding in winter. Two to four young or kits are born. Beaver feed primarily at night on serviceberry, willow, black cherry, poplar, yellow birch, and maple. Oaks are less preferred. They will eat hemlocks in spring, little later. After abundant supplies of these are depleted by a family, they will eat pine, alders, etc. and will eat crops (e.g., corn, soybeans, clover). In many forested areas, their activities (felled trees) block roads and flood some roads. They readily close road culverts, thus causing flooding.

The animal has become a pest and may trees, landscaping, orchards by its gnawing and may flood trees and crops.

Management

Beavers can be reintroduced to some areas to enrich the wildlife resource (restoring areas to pre-settlement species richness), restore a native resident, improve stream hydrology, and improve soil moisture and nearby site quality (by animal-built dams). Through transplanting wild beavers, land owners can secure the dams and flooded areas so valuable to aquatic and terrestrial wildlife resources, achieve unusual wildlife viewing areas (e.g., rich bird life), ponds, terraces, groundwater recharge, and limited flood control. They may provide a valuable recreational and backcountry resource as well. Their pond-area flooding will, however, kill trees along stream banks and within flooded areas but this may well be by design, not viewed as loss (since these trees are often previously unusable or inaccessible).

They may become a major pest in energy forests (e.g., and poplar areas). They, as so many other wildlife, can provide rich benefits but also high losses and management costs.

Management may include exclusion fencing (e.g., landscape plants and orchard trees). Harassment may cause families of beaver to move from an area (destination problems?). Dams being destroyed several times in rapid succession may cause families to relocate. Live-trapping and re-location may be used (destinations sites are now limited).

They must be regularly limited to desired population numbers and areas by trapping. Their dams or the maximum height that the water may reach must be regulated by water level control devices built into the dams (or dams destroyed by dynamite). Many control devices have been developed. A resource book for solutions is available.

Trapping is regulated by state laws and rules and these need to be followed as well as influenced annually as part of the local management strategy. The laws protect the animal, distribute the harvest, help retain prices that maintain the services of select people for effective control of the animals and their effects. Management includes schools to improve trapping, care of animals, care and cleaning of pelts, and marketing. It also includes tours, blinds, night observations, educational trips, and camera work. In-place TV-cameras have enabled people to observe dam building and repairs.

Surveys Management includes monitoring and inventorying the population as well as its use and effects (losses).To get an estimate of the total number of beavers in an area, aerial counts are made of the lodges and the number multiplied by 5.2, the average per colony. The regional trend is best done simply from standard regular flight lines and counts of signs of lodges and dams. Where beavers build dams or select sites that are suitable has been well quantified and predictive models have been developed.

Submitted by Robert H. Giles, Jr.

This Web site is maintained by R. H. Giles, Jr.
Last revision June 3, 2001