Mass flowering crops enhance pollinator densities at a landscape scale

The EU response to recent declines in pollinators and consequent loss of pollination services has been the inclusion of pollinator-friendly management in agri-environment schemes. These comprise the promotion of semi-natural habitats, such as set-aside and field margin strips. Yet, mass flowering crops, such as oilseed rape, are assumed to be of little value to pollinators.

However, in an article soon to appear in Ecology Letters, C. Westphal, I. Steffan-Dewenter and T. Tscharntke show that the densities of bumblebees, a key group of pollinators in European agroecosystems, did not appear to be related to the amount of semi-natural habitats, as previously thought. Instead, bumblebees profited from the availability of mass flowering crops, such as oilseed rape. Bumblebee densities were only enhanced in agricultural landscapes where the copious food supply was available at the landscape scale. In future conservation schemes the importance of mass flowering crops and the necessity to manage landscapes, not just local habitats as currently practised, must be considered.