Incorporating environmental uncertainty into species management decisions: Kirtland's Warbler habitat management as a case study

We present a framework for expressing species management objectives that incorporates the inherent riskiness of species management strategies. This framework identifies two critical parameters in the management objective: the population level that one would like to achieve and the minimum acceptable probability of attaining that population objective with a given management strategy-the safety margin. We then explore the implications of imposing a management objective in this form on habitat management decisions for the Kirtland's Warbler (Dendroica kirtlandii). We used a stochastic simulation model to generate probability distributions for Kirtland's Warbler population outcomes under different management strategies. The management parameter we varied was rotation length of commercial logging, and the cost of each rotation length was calculated as the opportunity cost of not operating at the profit-maximizing rotation length. The cost and warbler population distribution associated with each rotation length were then used to derive cost curves for the two critical decision parameters-population level and safety margin. For most of the range of values analyzed, the relationships between cost and both population objective and safety margin are linear. In addition, the rate at which cost rises with population objective increases as the safety margin required for that objective is raised.