Landscape context not patch size determines bumblebee density on flower mixtures sown for agri-environment schemes

Bumblebee declines across Europe have been linked to loss of habitat and forage availability due to agricultural intensification. These declines may have severe ecological and commercial consequences, since bumblebees pollinate a range of wildflowers and crops. In England attempts are being made to reintroduce forage resources through agri-environment schemes, yet there are few data on how the area of forage, or landscape context in which it is provided, affect their success. We investigated the effects of sown forage patches on bumblebees across sites varying in landscape characteristics. Bumblebee densities were higher on sown patches compared to control habitats but did not vary with patch size, i.e. total forager numbers were proportional to patch area. Importantly, the relative response to sown forage patches varied widely across a landscape gradient such that their impact in terms of attracting foraging bumblebees was greatest where the proportion of arable land was highest.