A meta-analysis of the impacts of field-edge flower plantings on pollinator conservation and ecosystem service delivery

Planting flowers along crop field edges is an increasingly common management strategy for addressing pollinator declines and improving crop pollination. However, no systematic review has been published that summarizes the efficacy of this specific management practice and how it impacts wild pollinators and pollinator-dependent crops. We conducted a systematic review and meta-analysis to determine whether such plantings 1) increase pollinator abundance or richness within field edges, 2) increase the abundance or richness of pollinators visiting crop flowers, or 3) improve crop yields. Our analysis of 54 studies suggests that field-edge flower plantings are highly effective at increasing pollinator richness and abundance in field edges and that plantings become more effective as they mature. However, the influence of field-edge plantings on crop pollination and yield is inconsistent. Planting size and richness did not change these results. Our analysis emphasizes that field-edge flower plantings consistently increase pollinator abundance and richness, but that there is a critical need for research on when and how plantings can improve ecosystem service provision and delivery. Determining if field-edge plantings affect pollinator pollination growth may uncover a mechanism for how plantings could improve crop pollination, while factors such as landscape context and crop-type may define when this happens.