Identifying and amending English agrienvironment scheme options to better support wild bees on farmland

Over the past century, agricultural intensification has resulted in the decline of farmland biodiversity. In order to mitigate and reverse these declines, agrienvironment schemes (AES) have been instigated across Europe. Typical pollinator-targeting AES options include sowing wildflower seed mixes. However, research suggests these mixes may be limited in their capacity to support the wider farmland bee fauna. This thesis considers amendments to these typical options. Firstly, by assessing the floral resources provided by different schemes; second, by trialling new wildflower seed mixes designed to attract a wider diversity of wild bees; and third, by investigating the potential of a novel scheme that could create additional nesting sites for farmland bee species. Farmland floral surveys demonstrated that few of the species sown in AES mixes persisted in the environment, with rapid floral abundance declines after five years, and only florally enhanced grass margins providing the majority of wildflower species required for attracting the wider bee fauna. Surveys of wild bee visitations to plants on a wildflower farm identified suitable candidate species for inclusion in a revised wildflower mix. Following this, trials using the amended seed mix, compared with typical AES mixes attracted significantly greater wild bee richness and abundance. Additionally, the typical Fabaceae-heavy ‘pollen and nectar mix’ had significantly lower sown floral abundance than the new mix, and was no better at attracting wild bees than an area of fallow. Finally, by trialling the creation of ‘scrapes’ on farmland margins, I identified an approach for creating nesting sites for ground nesting bees and wasps close to floral resources. Overall, these results indicate that wildflower seed mix AES need updating to include species that persist for longer in the environment, as well as attract the wider bee fauna on farmland, and that nest-site creation could be included in schemes to further support farmland bee populations.