Authors: Riggi, Laura; Lundin, Ola;Berggren, Åsa ;

Insect pollinator species declines in agroecosystems are concerning, and addition of floral resources to sustain pollinators is encouraged in agri-environmental schemes. The amount of floral resources in agroecosystems can be increased by growing mass-flowering crops (MFC). However, the benefit of MFC on insect pollinator densities and species richness seem context-dependent. In this presentation, we show the effects of MFC on insect pollinators in a case study and in a meta-analysis.
From a case study in Sweden, we found greater bumblebee species richness following bloom of mass-flowering red clover. The results indicate that late flowering MFC offer food resources during a time when these are scarce and that this has a potential to benefit less common bumblebee species.
On the other hand, a meta-analysis shows that increasing MFC cover generally has negative effects on wild pollinator densities and species richness, predominantly in crop habitats. No evidence was found of pollinator spill-over from crop to non-crop habitats after MFC bloom.
From our findings, we conclude that only the densities of a few pollinator species adapted to the flowering crop benefit from MFC. Therefore increasing the cultivation of MFC will not ensure conservation of pollinator species.