Feasibility of non-lethal approaches to protect riparian plants from foraging beavers in North America

Beavers in North America will occupy almost any wetland area containing available forage. Wetland restoration projects often provide the resources necessary for dispersing beavers to create desirable habitats. Their wide distribution and ability to disperse considerable distances almost assure that beavers will establish themselves in new wetlands. Although beavers are a natural and desirable component of a wetland ecosystem, their foraging behaviours can be destructive. Fencing may be a feasible approach to reduce damage to small, targeted areas, and textural repellents may provide some utility to protect established trees. However, these non-lethal approaches will be marginally effective when beaver populations become excessive. Beaver populations need to be maintained at levels that permit viable colonies while still permitting plant communities to flourish. This will require a better understanding of beaver movements, site and forage selection, and reproductive characteristics. This is particularly true when management objectives and regulations prohibit beaver removal from project sites. Rats, Mice and People: Rodent Biology and Management 76 additional animals to invade the site. Beavers may be coming from the river to forage on vegetation surrounding the demonstration sites. Roads surrounding demonstration ponds were marked by beavers dragging cut trees across them, and evidence suggested beavers were using the demonstration ponds as corridors to reach and cut larger trees. Although the Tres Rios group recognised that beaver activity had to be suppressed, they did not consider lethal removal a viable option. Capture and removal also was not possible because beavers already occupied the desirable habitat in Arizona. Placing additional animals in these areas would have only made new animals vulnerable to starvation, or caused displacement of existing animals. The only alternative options were to exclude beaver from desirable plants, or reduce desirability of plants or the site. Objectives of this study were to assess the: (1) efficacy of fencing and frightening devices to protect aquatic vegetation; (2) efficacy of fencing, frightening devices, and textural repellent to reduce gnawing of cottonwood trees; and (3) impact of these non-lethal approaches on other wildlife species.