Download a PDF containing all abstracts from the conference.

I.1-4: Cross-seasonal models reveal evidence for density-dependence, climate-mediated survival, and harvest compensation in mallards

Presented by Benjamin S. Sedinger - Email: Ben.Sedinger@uwsp.edu

Demographic studies and surveys of plant and animal populations are the foundation of conservation biology, wildlife and land management, and much of ecology and evolutionary biology. These studies are critically important for understanding the effects of climate, density-dependence and habitat, and direct anthropogenic impacts (e.g., harvest) on plant and animal populations. Further, species which experience direct anthropogenic impacts in the form of commercial or sport harvest might also be more susceptible to rapidly increasing anthropogenic impacts on the global environment. Given existing paradigms, managers often restrict or increase harvest to attempt to influence population trends. However, recent research has questioned the current paradigm of purely additive sport harvest, which posits that survival, population growth rates, and harvest are directly linked. As such, the use and further development of existing longitudinal datasets is of critical importance as researchers attempt to understand the effects of human impacts on populations of organisms, where existing datasets may provide clues to the management of under-studied species. North American waterfowl populations are among the most extensively surveyed and marked vertebrate organisms on the planet, where they serve as an excellent model system to examine the effects of anthropogenic impacts and climate on wild organisms. From 1961-2016, over 1.9 million mallards were released in the Pacific, Midcontinent, and Atlantic mallard populations both prior to and after the hunting season. We use recently developed Bayesian hierarchical model structures to examine seasonal, cause-specific mortality rates of three North American mallard (Anas platyrhynchos) populations. We show evidence for seasonal harvest compensation in three North American mallard populations, for both males and females. Additionally, our results indicate that harvest mortality is positively affected by abundance while natural mortality is mediated by climactic factors during both summer and winter seasons.
Session: Harvest Dynamics & Management (Friday, August 30, 8:15 to 10:00)