Abstract/Summary

Agri-environment schemes fund landholders to manage land to achieve environmental objectives and other public goods. Previous research has shown that individual scheme interventions can boost wild pollinator populations locally. However, the effect of an entire scheme at a national scale has never previously been assessed. The location of every intervention implemented in England during 2016 was mapped and schemes’ predicted impact on bee abundance and pollination services was modelled using a validated, processbased spatial model (poll4pop), which simulates foraging and population dynamics. The study considered four wild bee guilds (incorporating bumblebees and solitary bees) and their visitation rates to four pollinator-dependent crops (oilseed rape, field beans, orchard fruit and strawberries). The modelling predicted that the scheme significantly increased ground-nesting (but not tree/cavitynesting) bee populations nationally. There were no significant increases in crop visitation at national scale, but some locally significant increases in ground-nesting bumblebee visitation to oilseed rape and field beans were predicted. Linear regression at 10 km scale was used to determine which interventions were driving increased oilseed rape and field bean visitation and found that hedgerow/woodland edge management dominated, due to high resource quality. Floral margins were estimated to provide more limited benefit, due to later resource phenology and low uptake. Fallow also had a strong effect, despite lower relative resource quality, implying effective placement with respect to crops. Finally, the effect of additional tree-planting interventions (hedgerows, agroforestry, and woodland) on bumblebee abundance and crop visitation (oilseed rape, field beans) was studied. This showed that hedgerow planting would deliver the greatest increase in bumblebee abundance, whereas fruit or willow agroforestry would increase crop visitation the most, due to higher co-location. Based on these findings, recommendations are set out for design of future schemes to help deliver greater and more resilient crop pollination services in arable landscapes.