Beaver habitat use and impact in Truckee River basin, California.

Increasing stream width and depth and decreasing gradient had the strongest positive effects on Castor canadensis habitat use. Some abandoned colony sites appeared to have been located on physically unsuitable habitat; others appeared to be physically suitable sites abandoned due to resource depletion. Local extinction of quaking aspen Populus tremuloides and black cottonwood P. trichocarpa occurred on 4-5% of stream reaches. Willow Salix spp. showed good vigor despite heavy use in most reaches.-from Authors