Protected area management has significant spillover effects on vegetation

The Kunming-Montreal Global Biodiversity Framework calls for rapid global expansion of protected areas in response to ongoing biodiversity loss and ecosystem degradation¹. One of its strongest selling points is the benefits protected areas provide to adjacent human communities^2,3. However, little attention has been paid to how policy and management can support such benefits. Here, to address this gap, I explored influences on the effect sizes of vegetation spillovers from a candidate 12,513 Australian protected areas, defining spillovers as the difference in vegetation outside a protected area that occurs as a consequence of the existence of the protected area⁴. In 2020, 71% (2,189) out of the 3,063 protected areas for which full analysis was possible had a positive spillover effect of 0.1 or greater on at least 1 of 10 vegetation cover classes. Many protected area types were significant predictors of spillover magnitude. The covariance explained by protected area type with local and contextual variables was 14%, suggesting that internal management moderates adjacent locations. These findings highlight the potential to include spillover effects explicitly in global policy frameworks and suggest a pathway to an empirical basis for monitoring and accounting schemes that support biodiversity conservation and ecosystem service provision adjacent to protected areas.