“We have got unprecedented geographic and taxonomic coverage on our database,” said Scharlemann. “It’s global — we’ve got studies from pretty much every continent except Antarctica — and we’re covering the whole taxonomic breadth.”
Overall, sites inside protected areas had 14.5 percent more species and 10.6 percent more individual organisms than unprotected sites. There are several possible explanations for this difference, says Scharlemann. Careful management could be increasing biodiversity within protected areas, or holding it steady while surrounding ecosystems are degraded. Additionally, people who establish protected areas are likely to choose sites that have high biodiversity to begin with. Whatever the reason, the findings suggest that animal and plant species are flourishing in protected areas — and that efforts to maintain and expand such areas are on the right track.