Ancient occupation by humans leads to missing bird diversity in otherwise natural habitats

Habitat modification is responsible for substantial biodiversity declines, but communities vary in their tolerance to land-use change. One infrequently queried possibility is that historical factors determine the sensitivity of contemporary communities. We use bird community data from 54 studies across the world to test the hypothesis that pre-historic human presence reduced community sensitivity to land-use change by eliminating sensitive species in natural habitats. We find that pre-historic human population size correlates with reduced sensitivity of communities. Primary vegetation in areas with larger pre-historic human populations contain fewer species today, while species richness in structurally simple agriculture is unimpacted. The greatest signal of humans impacts dates back to 12,000 YBP suggesting that early humans may have caused even more widespread extinctions, than previously appreciated. One-Sentence Summary Areas with high human population 12,000 years ago have less biodiversity today, but are more tolerant of habitat modification