SEDIMENTATION-RATES AND PATTERNS IN BEAVER PONDS IN A MOUNTAIN ENVIRONMENT

Sediment depth was measured at several sites within each of eight beav er ponds in Glacier National Park, Montana, and sediment samples were collected from five of these ponds. Accumulation rates of sediments fa r exceeded published rates from boreal forest landscapes in eastern an d central North America. Pond area strongly predicts volume of sedimen tation. Textural differences illustrated spatial variations associated with position in a pond and along a pond sequence. Organic matter con tent was significantly higher in older ponds, and has ramifications fo r the development of the benthos and the long-term storage of matter i n ponds. The role of beavers as biogeomorphic agents is profound, but requires further elucidation to distinguish between fluvial sediment d eposition in ponds and sediment deposition associated with beaver exca vational activity.