Impact of pesticide use on wild bee distributions across the United States

Abstract

The decline of many wild bee species has major consequences for pollination in natural and agro-ecosystems. One hypothesized cause of the declines is pesticide use; neonicotinoids and pyrethroids in particular have been shown to have pernicious effects in laboratory and field experiments, and have been linked to population declines in a few focal species. We used aggregated museum records, ecological surveys and community science data from across the contiguous United States, including 178,589 unique observations from 1,081 bee species (33% of species with records in the United States) across six families, to model species occupancy from 1995 to 2015 with linked land use data. While there are numerous causes of bee declines, we discovered that the negative effects of pesticides are widespread; the increase in neonicotinoid and pyrethroid use is a major driver of changes in occupancy across hundreds of wild bee species. In some groups, high pesticide use contributes to a 43.3% decrease in the probability that a species occurs at a site. These results suggest that mechanisms that reduce pesticide use (such as integrative pest management) can potentially facilitate pollination conservation. Bees provide important pollination ecosystem services in agricultural landscapes, but the extent to which they are affected by pesticide use on a continental scale has yet to be explored. This study evaluates the impact of pesticide use on wild bee populations across the contiguous United States.