Pollination service to urban agriculture in San Francisco, CA

Urban agriculture can increase the sustainability of cities by reducing their ecological footprint, conserving biodiversity, and improving quality of life in a city. Given the environmental, economic and social value of urban agriculture, it is important to understand the ecosystem services that sustain it. We experimentally investigated how pollination by wild bees affects tomato production on 16 urban agriculture sites in San Francisco, CA. By comparing four pollination service indicators (fruit set, fruit mass, yield, and seed set) in four pollination treatments (open, artificial-self, artificial-cross, control), we were able to determine that tomatoes pollinated by wild bees significantly outperform the control in terms of all four pollination service indicators measured. Furthermore, the results of this study indicate that urban areas can support adequate pollination service to urban agriculture, regardless of garden size, garden age, or proportion of impervious surface in the surrounding matrix, and that floral resource density is a major factor influencing pollination service.