Abstracts

Presented by Glen Brown - Email: glen.brown@ontario.ca

Black ducks have been of management concern for decades due to a long-term declining trend. The cause of declines remains unclear and little is known about what factors affect population dynamics in the boreal forest of eastern Canada. We assembled several long-term data sets (spanning 30 + years) to clarify drivers of black duck productivity on the breeding range in Ontario, including the Acid Rain Biomonitoring Program (Environment and Climate Change Canada) and the Eastern Breeding Waterfowl Survey. The detailed breeding pair, brood count and wetland specific environmental data were used to characterize the relationship between black duck productivity and habitat on breeding range, including the relative contributions of waterfowl densities (black duck and mallard), spring weather conditions, land cover change, human landscape disturbance, acidification impacts and recovery and the associated effects on habitat quality. We used a hierarchical mixed modeling framework to assess trends and the relative importance of hypothesized covariates. Clarifying uncertainties in how these drivers affect annual variation or trends in productivity will improve the utility of adaptive management models employed by the Black Duck Joint Venture and better inform decisions regarding habitat management and harvest.