Cost-effective habitat protection: the case of Pacific salmon

In recent years a large literature on “reserve site selection” has developed at the interface between operations research, ecology, and environmental economics. Reserve site selection models use numerical optimization techniques from operations research to select sites for a network of nature reserves for protecting biodiversity. Most reserve site selection applications have focused on protecting terrestrial biodiversity using data on species occurrences in each of the candidate sites. In this paper, we develop a stochastic model of salmon population dynamics and incorporate it into a reserve site selection framework for prioritizing protection efforts in upstream watersheds. We use spawner return data for three closely related salmon stocks in the Upper Columbia River basin and estimates of the economic impacts of watershed protection from NOAA to illustrate the framework. Simplified prioritization criteria based on costs only, a static index of biological benefits only, or baseline benefit-cost ratios are compared to an approach that updates the benefits of protection through the course of the selection process. Our preliminary results suggest that there can be strong interactions between protection efforts in connected watersheds and that site selection approaches that account for these interactions can improve the cost effectiveness of watershed protections substantially.