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Developing Models of Black Duck Populations in North America
Research Objectives
The primary objective of this project is to develop
predictive models of population response to management activity, based on
demographic estimates, on environmental covariates, and on competing
hypotheses about black duck population dynamics. These models can be developed
at several scales; a landscape level model that predicts dynamics of regional
or continental populations, and a regional model in which population dynamics
for smaller regions (such as banding reference areas) are predicted as a
consequence of local demographic and environmental conditions. The management
options (the partially controllable components of the model) differ between
models at these scales, as do the requirements for monitoring.
The North American Waterfowl Management Plan states a population goal of 385,000 black ducks in the combined Mississippi and Atlantic Flyways. Unfortunately, there is still little agreement among researchers regarding the relative importance of harvest, habitat change, and interspecific interactions in causing the decline in black ducks.
One method of increasing our understanding
of both habitat and harvest management is adaptive resource management.
Under this approach, management is used to increase our knowledge of the
system. In particular, it is useful in the case where several possible
management options exist and where there is debate about population responses
to these options. By formulating a series of alternative models about the
effects of management and the environment on the population, and then by
evaluating the consequences of selected management actions on the population,
we can improve our understanding of which model provides the most reasonable
description of the system.