ORIGINAL PAPER Vegetative composition and community structure associated with beaver ponds in Canaan valley, West Virginia, USA Jerri L. Bonner Æ James T. Anderson Æ James S. Rentch Æ William N. Grafton Received: 22 January 2008 / Accepted: 16 January 2009 / Published online: 3 February 2009 Ó Springer Science+Business Media B.V. 2009 Abstract Beavers (Castor canadensis) can cause dramatic changes in vegetative composition and diversity. Although alterations by beaver have been studied extensively, little attention has been paid to the effects beaver impoundments have on rare plants. Effective conservation of riparian and wetland rare plant species must consider the responses of vegeta- tion to changes in hydrology that can occur when beaver populations are present. The goal of this research was to establish the occurrence of locally rare plant species, examine community composition, and analyze vegetative community structure of veg- etation associated with beaver ponds in Canaan Valley, West Virginia, USA. Species richness and diversity were similar between plots located inside beaver ponds and adjacent to beaver ponds (P [ 0.05). Although no significant difference in rare plant species was detected among pond ages, the oldest ponds ( [ 56 years) had twice as many rare species as the youngest ponds (B6 years). The youngest ponds had higher overall mean species richness (S) than ponds 7–56 years old (P \ 0.05), but S returned to similar levels in the oldest ponds. Of the 15 rare species observed, most were classified as obligate (9) or facultative wetland (4) species. The youngest ponds contained the fewest number of rare species. Multiple response permutation procedure (MRPP) analyses of community structure detected no relation between community composition and either pond age or size. However, both MRPP and non- metric multi-dimensional scaling showed proximity to pond was important in herbaceous community structure. Wetlands in beaver ponds also were shown to be distinct from adjacent wetland areas. Conser- vation of existing beaver populations is necessary so that the entire spectrum of pond ages is available for the maintenance of rare plant species and communities. Keywords Canaan valley  Castor canadensis  Pond  Rare plant species  Vegetation Introduction Beavers (Castor canadensis Kuhl) influence streams and wetlands across much of North America. The dam-building activities of these semi-aquatic mam- mals alter forest succession by flooding areas (Barnes and Dibble 1988; Naiman et al. 1988), leading to J. L. Bonner  J. T. Anderson (&)  J. S. Rentch  W. N. Grafton Division of Forestry and Natural Resources, West Virginia University, P.O. Box 6125, Morgantown, WV 26506-6125, USA e-mail: jim.anderson@mail.wvu.edu Present Address: J. L. Bonner North Carolina Wildlife Resources Commission, P.O. Box 87, Rowland, NC 28383, USA 123 Wetlands Ecol Manage (2009) 17:543–554 DOI 10.1007/s11273-009-9131-0