A general framework for prioritizing land units for ecological protection and restoration

Past methods of prioritizing sites for protection and restoration have focused on lists of criteria or algorithms. These methods lack a common underlying framework, such that the process is explicit and repeatable, assumptions are highlighted, and commonalities and differences among prioritizations can be readily assessed. Our objective in this paper is to provide such a framework for cases where the goal of setting priorities is to maximize the ecological benefit gained from limited resources. We provide simple and general models that can be used to prioritize sites based on the projected ecological benefit per unit restoration or protection effort and to estimate the total projected benefit of restoring or protecting a set of sites. These models, which are based on an expression of the functional relationship between an end point and effort, hold up under a variety of situations and provide a common language for prioritization. We then discuss procedures for estimating model terms-calculations from regression curves when data are available, and use of judgement indicators when data are relatively limited. Finally, we present two case studies that apply the models and examine selected past prioritizations in the context of our framework.