Managing excessive predation in a predator-endangered prey setting

Abstract

Bioeconomic analyses of predator–prey systems examine how to adjust species management in response to predation spillovers to avoid inefficiencies. Predation spillovers refer to the net economic value of predation, taking into account the impacts on prey. Inefficiencies arise when the species interactions that generate this value are not managed to maximize the net economic surplus generated by the system. Consumptive values for predator and/or prey harvests factor into the value of predation spillovers in prior work. In contrast, we examine the optimal management of a predator–prey system where the only values are non-market values associated with the species' abundances. We find that adverse predation spillovers may alone create social incentives for harvests or other interventions. Moreover, optimally reducing adverse predation spillovers may increase both species' abundances — an ecological “win–win” outcome that increases economic surplus, although the result depends on the controls used. We examine predator removal and predator exclosures that shelter prey from predation. Using a numerical example of the Great Lakes Piping Plover, an endangered prey bird, and Merlins, a falcon predator, we find predator exclosures can reduce inefficiencies and produce a win–win outcome.