Evaluating and augmenting pollinator communities in diversified organic farming systems

Diversified farming systems are highly reliant on stable and diverse native bee communities for crop production throughout a season. Growth in diversified farming systems has been rapid in the United States, particularly in urban areas. However, we often have a poor understanding of the native bee communities that provide pollination services in these systems, or the factors that affect these communities. Here, we characterized the native bee communities on a network of small-acreage diversified produce farms in western Washington. These farms were selected along a gradient of urbanization, and sampled for native bees three times (May, July, September) in 2014 and 2015. These data were analyzed to determine if native bee communities were more abundant and diverse in urban compared to rural farming systems and in less intensive landscapes. We also explored the potential impacts of habitat augmentation on native bee communities across our landscape gradient. Our results indicate that native bee community assemblages vary with landscape intensity and floral diversity. Moreover, our findings expound the importance of native bee conservation and augmentation in diversified farming systems, particularly those imbedded in high intensity urban landscapes.