Matthieu Guillemain G Scott Boomer Jean-Dominique Lebreton James D. Nichols Evan G. Cooch 2014 <p>Change in the size of populations over space and time is, arguably, the motivation for&nbsp;much of pure and applied ecological research. The fundamental model for the&nbsp;dynamics of any population is straightforward: the net change in the abundance is the&nbsp;simple difference between the number of individuals entering the population and the&nbsp;number leaving the population, either or both of which may change in response to&nbsp;factors intrinsic and extrinsic to the population. While harvest of individuals from a&nbsp;population constitutes a clear extrinsic source of removal of individuals, the response&nbsp;of populations to harvest is frequently complex, reflecting an interaction of harvest&nbsp;with one or more population processes. Here we consider the role of these interactions,&nbsp;and factors influencing them, on the effective harvest management of waterfowl&nbsp;populations. We review historical ideas concerning harvest and discuss the&nbsp;relationship(s) between waterfowl life histories and the development and application of&nbsp;population models to inform harvest management. The influence of population&nbsp;structure (age, spatial) on derivation of optimal harvest strategies (with and without&nbsp;explicit consideration of various sources of uncertainty) is considered. In addition to&nbsp;population structure, we discuss how the optimal harvest strategy may be influenced by:&nbsp;1) patterns of density-dependence in one or more vital rates, and 2) heterogeneity in&nbsp;vital rates among individuals within an age-sex-size class. Although derivation of the&nbsp;optimal harvest strategy for simple population models (with or without structure) is&nbsp;generally straightforward, there are several potential difficulties in application. In&nbsp;particular, uncertainty concerning the population structure at the time of harvest, and&nbsp;the ability to regulate the structure of the harvest itself, are significant complications.&nbsp;We therefore review the evidence of effects of harvest on waterfowl populations. Some of this evidence has focussed on correspondence of data with more phenomenological&nbsp;models and other evidence relates to specific mechanisms, including densitydependence&nbsp;and heterogeneity. An important part of this evidence is found in the&nbsp;evolution of model weights under various adaptive harvest management programmes&nbsp;of the U.S. Fish and Wildlife Service for North American waterfowl.</p> <p>Overall, there is substantial uncertainty about system dynamics, about the impacts&nbsp;of potential management and conservation decisions on those dynamics, and how to&nbsp;optimise management decisions in the presence of such uncertainties. Such&nbsp;relationships are unlikely to be stationary over space or time, and selective harvest of&nbsp;some individuals can potentially alter life history allocation of resources over time &ndash;&nbsp;both of which will potentially influence optimal harvest strategies. These sources of&nbsp;variation and uncertainty argue for the use of adaptive approaches to waterfowl&nbsp;harvest management.</p> application/pdf en Wildfowl and Wetland Trust The effects of harvest on waterfowl populations article