The Aichi biodiversity target 11 commits parties to the Convention on Biological Diversity (CBD) to increasing protected terrestrial areas to 17 per cent by 2020. Protected areas are, however, expensive to maintain and quantifying their effectiveness is therefore crucial. This study present a global analysis of how successful protection is in terms of sustaining biodiversity.
Comparing protected sites with matched unprotected counterparts, the researchers found richness and abundance to be higher in protected sites, however, rarefied richness did not differ. By using GBIF-mediated occurrences to determine range sizes, they also found evidence that protection has little effect on the proportion of individuals within a community that have narrow geographic ranges. Within the protected areas, the most likely explanation of the effects appeared to be differences in land use. The study reinforces the importance of protected areas, but stresses that the effectiveness of protection must be studied to be improved further.