Action: Increase areas of rough grassland for bumblebee nesting
One replicated controlled trial on lowland farms in Scotland showed that grassy field margins attracted nest-searching queen bumblebees in spring at higher densities than cropped field margins, managed or unmanaged grasslands or hedgerows.
Supporting evidence from individual studies
A replicated, controlled trial of the Rural Stewardship agri-environment scheme on 10 farms in Scotland found that 1.5 to 6 m wide grassy field margins attracted nest-searching queen bumblebees at higher densities than managed or unmanaged grasslands or hedgerows (Lye et al. 2009). On five farms with the agri-environment scheme, researchers counted an average of around nine nest-searching queens/100 m on grassy field margins, compared to around seven nest-searching queens/100 m in species-rich grassland transects, five for conventional arable field margins, and four on unmanaged (abandoned) grassland transects. The study did not record the numbers of established nests later in the year.