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J.4-3: Did duck population trajectories change with anthropogenic disturbance in the Boreal Plains ecozone?

Presented by Howard Singer - Email: h_singer@ducks.ca

Anthropogenic disturbances in the boreal forest are hypothesized to negatively affect breeding ducks. We examined relationships between population trajectory of duck pairs and amount of anthropogenic disturbance in the Boreal Plains ecozone of western Canada. Population trends were compared to density of seismic lines, pipelines, roads, and well sites, and distance to agriculture. We also evaluated whether relative importance of these disturbances differed in agriculture encroached vs. unencroached landscapes; distance to agriculture was assessed in unencroached landscapes. Pair counts (1960 2007) from the Waterfowl Breeding Population and Habitat Survey were pooled into nesting guilds (cavity, ground, and overwater). Relationships between anthropogenic disturbance variables and population trajectory was assessed using linear mixed modeling and multi-step random coefficients models, which controlled for habitat and weather variables. Relative magnitude and direction of relationships with disturbances varied with landscape and nesting guild. Overall, majority of negative relationships occurred with seismic lines and pipelines, with lower population trends in four of six comparisons for both disturbance types, while trends increased closer to agriculture. We then examined cumulative effects by mapping spatial variation in predicted percent change in duck abundance. Population trends for ground nesters tended be most negative in regions with high seismic line and well pad density in agriculture encroached landscapes and in regions with high seismic line and pipeline density in unencroached landscapes. Cavity nester population trends were generally positive throughout the study area but were lowest in unencroached landscapes farthest from agriculture. Overwater nester trends were generally lowest in agriculture encroached landscapes with high densities of seismic lines, roads and well pads and in unencroached landscapes with high densities of seismic lines, pipelines and roads. While our work suggests that anthropogenic disturbances, particularly seismic and pipelines, may merit further consideration as foci for conservation, additional research is needed to quantify demographic implications.
Session: Ducks in the North (Friday, August 30, 13:20 to 15:00)