The data on protected areas were based on the May 2016 release of the World Database on Protected Areas (retrieved from and produced by the UN Environment World Conservation Monitoring Centre) (40). We only selected areas belonging to IUCN protected area categories I to VI and having status as “designated,” “inscribed,” “established,” or “adopted” (all meaning that the protected area is designated). Areas marked as “Proposed” were removed, as well as all protected areas lacking polygonal representation. To prevent overestimation of the areal coverage of protected areas caused by overlapping designations, we merged polygons into a single layer.