Crop land flooded by beaver activity. USDA Photo
Following centuries of over-harvest, the American beaver has made an amazing comeback and now occupies much of its historical range in North America. But with this successful recovery comes a variety of challenges for managing beaver damage due to flooding from beaver dams and plugged culverts. Resolving conflicts with beaver flooding requires an integrated approach that includes both lethal and nonlethal techniques. In a recent review, NWRC researchers highlight the evolution of modern nonlethal approaches to control water levels at beaver dams.
“Traditional nonlethal methods for dealing with beaver flooding involve either exclusion or deception,” states Dr. Jimmy Taylor at NWRC’s Oregon field station. “Fence systems exclude beaver from certain areas while pipe systems attempt to modify beaver behavior by reducing water sound and movement. Although there is no scientific evidence to back it up, some believe that beavers are attracted to the sound and movement of water which cues their damming behavior.”
It wasn’t until the 1980-1990s that exclusion and deception were combined to create flow devices. Flow devices, such as the Clemson pond leveler or flexible pipe and fence systems, allow managers to maintain desired water levels and reduce flooding. In some instances, flow devices may be an effective nonlethal tool for maintaining beaver ponds; however, the authors note that most device failures are due to beaver moving their activities upstream or down-stream.
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