For centuries beaver (Castor canadensis) have been altering stream systems in North America. In this study, Naiman et al. measured stream inputs and outputs and examined physical and biological parameters to determine the effects of beaver on riparian structure and function. Beaver were directly responsible for the presence of 53% of the fine wood in streams and the indirect effects of their dams (ponding, saturated soils, etc.) caused 50-60% of the remaining fine wood to be present in the stream. Ponds behind beaver dams retained large amounts of sediment, resulting in decreased sediment availability to the rest of the watershed, which in turn, produced more carbon and had much slower decay rates than surrounding streams. In general, beaver had the greatest impact on middle order (2nd-4th) streams, as they preferred to build their dams in streams this size, however secondary and long term effects of beaver were evident throughout the watershed.
Citations and enhanced abstracts for journals articles and documents focused on rangeland ecology and management. RSIS is a collaboration between Montana State University, University of Idaho, and University of Wyoming.