The expansion of pollinator-dependent crops, especially in the developing
world, together with reports of worldwide pollinator declines, raises
concern of possible yield gaps. Farmers directly reliant on pollination
services for food supply often live in regions where our knowledge of
pollination services is poor. In a manipulative experiment replicated at
23 sites across an Ethiopian agricultural landscape, we found poor
pollination services and severe pollen limitation in a common oil crop.
With supplementary pollination, the yield increased on average by 91%.
Despite the heterogeneous agricultural matrix, we found a low bee
abundance, which may explain poor pollination services. The variation in
pollen limitation was unrelated to surrounding forest cover, local bee
richness and bee abundance. While practices that commonly increase
pollinators (restricted pesticide use, flower strips) are an integral part
of the landscape, these elements are apparently insufficient. Management
to increase pollination services is therefore in need of urgent
investigation. Samnegard_Proc_R_Soc_B_2016_Bee_surveySamnegard_Proc_R_Soc_B_2016_Rapeseed_dataSamnegard_Proc_R_Soc_B_2016_Landscape_local_variables