This study investigated the relationship between flood duration of beaver ponds in eastern Ontario and their productivity for waterfowl. The primary objective was to assess the effect of removing water from a beaver pond for one year had on the subsequent productivity of the wetland. Productivity was estimated by sampling water chemistry, standing crops of aquatic invertebrates, vertebrates, algae and vegetation composition and distribution in naturally occurring and managed beaver ponds of varying ages during 1994 and 1995. Three ponds in each of the following categories were sampled; managed ponds reflooded in 1993, managed ponds reflooded in 1991, naturally occurring beaver ponds reflooded in 1992-93, and naturally occurring old flood ponds ($>$5 years old). / Results from this study indicate that beaver pond productivity is negatively affected by flooding duration. Removal of a portion of the beaver dam on old flood ponds may be an effective means of rejuvenating the wetland. Positive effects on the productivity of the wetland should be realized for several years after reflood. Variability in results indicates that other environmental variables were also affecting the overall productivity of beaver ponds. (Abstract shortened by UMI.)

No description available.