The effects of landscape and forage patch size on the response of bumblebees to restored habitats in agricultural landscapes

摘要

European bumblebee declines, linked to the intensification of agriculture, mayhave severe consequences for pollination services. Attempts to restore foragehabitats for bumblebees through agri-environment schemes have not consideredhow the area of forage or landscape context affects their success. We investigatedthe effects of sown forage patches of different sizes on bumblebee foragerdensities across sites representing a gradient of landscape complexity. Bumblebeedensities were higher on forage patches compared to controls but did not varywith patch size, suggesting that, between areas of 0.25 ha to 1 ha, total foragernumbers increase approximately linearly with patch area. Importantly, the relativeresponse to forage patches varied widely across a landscape gradient. Bycomparing bumblebee densities both on sown forage patches and in thesurrounding landscape, we demonstrate that this variation arises because theimpact of these patches in attracting foraging bumblebees is greater where theproportion of arable land is highest.