The effect of beaver dams on salmonid abundance in the West Branch of the Maple River

Abstract

The effect of the North American beaver ( Castor canadensis ) on stream ecosystems has been a contentious subject for many wildlife managers. Some studies suggest negative impacts on fish salmonid communities, whereas other studies have found the opposite. The goal of this study was to determine if beaver dams in a small Michigan stream increased or decreased salmonid abundance. Using a non-invasive observational approach, two different sections of the West Branch of the Maple River were sampled, one stretch containing five beaver dams and the other stretch containing none. It was found that salmonid abundance did not differ significantly between dammed and dam-free stretches of the river. Beaver dams in this specific stream appear to be a benign factor when considering salmonid abundance, which suggests that beaver dams do not need to be removed in order to maintain a healthy salmonid community. With regards to practical applications of said research a wildlife manager armed with this information can make more informed decisions when deciding how to properly manage streams similar to the West Branch of the Maple River.