Evaluating the effectiveness of wildflower seed mixes for boosting floral diversity and bumblebee and hoverfly abundance in urban areas

There is growing interest in improving the biodiversity of urban and suburban areas. Here we report on the effectiveness of a very simple intervention that may be used to boost flower and pollinator abundance; the sowing of plots of wildflowers in amenity grasslands. The abundance of flowers, bumblebees (Bombus spp.), and hoverflies (Syrphidae) was surveyed in 30 such plots, either 1 or 2 years after they had been sown. Overall, sown plots had 25 times more flowers, 50 times more bumblebees, and 13 times more hoverflies compared to paired control plots. Floral abundance and bee abundance increased from year 1 to year 2, but hoverflies were more abundant in plots in their first year, reflecting their preference for shallow annual flowers. Our data demonstrate that flower-poor amenity grasslands can be readily converted to flower-rich areas that are highly attractive to pollinators, providing a simple tool for pollinator conservation in urban areas. © 2014 The Royal Entomological Society.