A modeling framework for integrated harvest and habitat management of North American waterfowl : case-study of northern pintail metapopulation dynamics / B.J. Mattsson, M.C. Runge, J.H. Devries, G.S. Boomer, J.M. Eadie, D.A. Haukos, J.P. Fleskes, D.N. Koons, W.E. Thogmartin, and R.G. Clark.

Includes bibliographical references (page 158).

We developed and evaluated the performance of a metapopulation model enabling managers to examine,
for the first time, the consequences of alternative management strategies involving habitat conditions
and hunting on both harvest opportunity and carrying capacity (i.e., equilibrium population size in the
absence of harvest) for migratory waterfowl at a continental scale. Our focus is on the northern pintail
(Anas acuta; hereafter, pintail), which serves as a useful model species to examine the potential for integrating
waterfowl harvest and habitat management in North America. We developed submodel structure
capturing important processes for pintail populations during breeding, fall migration, winter, and spring
migration while encompassing spatial structure representing three core breeding areas and two core
nonbreeding areas. A number of continental-scale predictions from our baseline parameterization (e.g.,
carrying capacity of 5.5 million, equilibrium population size of 2.9 million and harvest rate of 12% at maximum
sustained yield [MSY]) were within 10% of those from the pintail harvest strategy under current
use by the U.S. Fish and Wildlife Service. To begin investigating the interaction of harvest and habitat
management, we examined equilibrium population conditions for pintail at the continental scale across
a range of harvest rates while perturbing model parameters to represent: (1) a 10% increase in breeding
habitat quality in the Prairie Pothole population (PR); and (2) a 10% increase in nonbreeding habitat
quantity along in the Gulf Coast (GC). Based on our model and analysis, a greater increase in carrying
capacity and sustainable harvest was seen when increasing a proxy for habitat quality in the Prairie Pothole
population. This finding and underlying assumptions must be critically evaluated, however, before
specific management recommendations can be made. To make such recommendations, we require (1)
extended, refined submodels with additional parameters linking influences of habitat management and
environmental conditions to key life-history parameters; (2) a formal sensitivity analysis of the revised
model; (3) an integrated population model that incorporates empirical data for estimating key vital rates;
and (4) cost estimates for changing these additional parameters through habitat management efforts. We
foresee great utility in using an integrated modeling approach to predict habitat and harvest management
influences on continental-scale population responses while explicitly considering putative effects of climate
change. Such a model could be readily adapted for management of many habitat-limited species.