Protected areas (PAs) are one of the most important and globally applicable approaches to halt biodiversity loss. Since the campaign to expand PAs began at the World’s Park Congress in 1982, nations have strived to increase the extent of land under protection (see figure below). Calls to further increase the global PA estate have been made. With so much land under protection, it is important to synthesise evidence on the impact of PAs, or how much difference they make to conservation outcomes, especially when they are criticised for being established in areas unimportant for biodiversity. Grounded on the principles of robust systematic review, Roshan Sharma at RMIT University recently led the publication of a protocol to search for, synthesise, and appraise the quality of evidence on PA impact on vegetation extent and condition.
