Influence of landscape simplification on pollination services to strawberry

Globally, more than 70% of food crops rely to some extent on pollination services provided by insects. Conservation of pollination services depends upon our understanding of the processes that influence pollinators at farm and landscape-scales. In this study we assessed the influence of the proportion of agricultural land in a 1 km radius around our field sites on the composition of the pollinator community and the level of services provided to cultivated strawberry (Fragaria ananassa). In addition we determined which floral visitors are the most effective pollinators. Using a combination of pan trapping and sweep netting, we collected pollinators on 15 farms in the Finger Lakes region of New York State with a gradient of 15 to 75% agricultural area in the surrounding landscapes. Landscapes with a greater proportion of agricultural area had significantly lower pollinator abundances but species richness was not affected. Similarly species richness had no effect on the level of pollination services; however, fruit weight tended to increase with greater honey bee abundance. Interestingly, wild pollinators in the genus Andrena, not honey bees, were the best pollinators of strawberry flowers on a single visit basis. Our results show that a high proportion of agricultural area in the landscape negatively impacts pollinator abundance, which in turn decreases pollination services to strawberry. Conservation strategies that preserve areas of semi-natural habitat in the landscape will be important for managing agro-ecosystems that are capable of sponsoring their own ecosystem services and maintaining yields.