No consistent effects of humans on animal genetic diversity worldwide

Human impacts on genetic diversity are poorly understood yet critical to understanding the evolutionary capacity of the worlds biodiversity. We used global maps of land use and human density to assess human impacts on the intraspecific genetic diversity of 15,946 species of birds, fishes, insects, and mammals over time and across four spatial scales worldwide. We analyzed 164,518 mitochondrial cytochrome c oxidase subunit I (COI) sequences to quantify changes in genetic diversity between 1980-2016. We found temporal change in genetic diversity, with both increasing and decreasing trends observed. The magnitude and sign of human impacts on genetic diversity depended on scale and taxon. In contrast, latitude was a strong predictor of diversity in fish, insects, and mammals. Our analyses provide a first worldwide picture of human impacts on animal genetic diversity. A global effort to systematically monitor genetic diversity is needed to fill the gaps in taxonomic and geographic coverage in this dataset.