Prioritizing reducing impacts on species to minimize residual reserves.

International conservation goals have driven rapid expansion of protected areas. This growth has favored quantity over quality, and often results in residual reserves (i.e., areas where species already experience minimal anthropogenic impact). Spatial prioritization is commonly used to help design protected area networks that represent species while minimizing costs to stakeholders. This approach can result in the siting of protected areas that do not decrease impacts on species of conservation concern. Here, we show how measures of cumulative impacts on species can be used in a spatial prioritization to site protected areas to reduce impacts on species of conservation concern. We use a trait-based vulnerability framework and anthropogenic stressor maps to quantify cumulative impacts from four human activities, and incorporate those impacts into spatial prioritizations. We demonstrate that the inclusion of cumulative impacts on species in spatial prioritization can more efficiently protect biodiversity, balance socioeconomic objectives, and avoid residual reserve outcomes.