One Earth, Volume 2, 24 January 2020,
Biodiversity is in rapid decline, largely driven by habitat loss and degradation. Protected area establishment and management are widely used to maintain habitats and species in perpetuity. Protected area extent has increased rapidly in recent years with area-based targets set within international conservation agreements such as the Convention on Biological Diversity's Aichi Target 11. Researchers have proposed new targets to guide conservation actions post-2020, but most do not provide concrete recommendations to practitioners on how to navigate the inevitable and complex decisions between conservation actions to achieve these goals. We propose a decision-theoretical framework to better achieve components of Aichi Target 11 (expand protected areas, improve representation of conservation features, and manage protected areas better). We provide summaries of current system states within our framework and recent evidence-based guidelines on allocating resources between states. These guidelines will enable the next generation of conservation investments to achieve better conservation outcomes.