Understanding local-scale drivers of biodiversity outcomes in terrestrial protected areas

Conservation relies heavily on protected areas (PAs) maintaining their key biodiversity features to meet global biodiversity conservation goals. However, PAs have had variable success, with many failing to fully maintain their biodiversity features. The current literature concerning what drives variability in PA performance is rapidly expanding but unclear, sometimes contradictory, and spread across multiple disciplines. A clear understanding of the drivers of successful biodiversity conservation in PAs is necessary to make them fully effective. Here, we conduct a comprehensive assessment of the current state of knowledge concerning the drivers of biological outcomes within PAs, focusing on those that can be addressed at local scales. We evaluate evidence in support of potential drivers to identify those that enable more successful outcomes and those that impede success and provide a synthetic review. Interactions are discussed where they are known, and we highlight gaps in understanding. We find that elements of PA design, management, and local and national governance challenges, species and system ecology, and sociopolitical context can all influence outcomes. Adjusting PA management to focus on actions and policies that influence the key drivers identified here could improve global biodiversity outcomes.