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In 2009 the USDA-NRCS asked the Urban Bee Lab at the University of California, Berkeley if urban bee-flower knowledge could be used to attract native bees to farms in Brentwood, Contra Costa Co. in Northern California. The overarching question was, could native bees play a role in supplementing honey bees by providing pollination services for crop flowers? If so, how many native bee species were visiting farms and how frequently did they occur?Eight small farms (4-60 ha) were selected to investigate this question; four were control and four were treatment farms where bee habitat gardens were constructed. Habitat gardens were stocked with native and non-native ornamental plants known to attract native bees (and honey bees).Bees were monitored yearly in spring at each farm from 2010-2016 to evaluate species richness and abundance, which yielded several findings:I. Farms near urban areas and a creek were consistently more attractive to diverse and abundant bee speciesII. Inconsistent bee garden maintenance and major changes in farm operations in other farms resulted in consistently lower measurements of bee richness and abundanceIII. Over the seven-year monitoring period, 144 bee species were recorded among all farmsIV. Nearby urban areas had most of the same species as the agricultural areas, suggesting a relationship of bees moving between two areasV. A total of 23 diverse native bee species were recorded from apple, berry, and cherry flowers, and many of them in substantial numbers, indicating that native bees were providing pollination servicesFinally, maintaining frequent professional contact with growers was considered crucial in conducting research over the long term. These contacts were also critical in designing outreach packages to growers who expressed interest in applying our native bee findings to their farming operations.

In mid 2003 a diverse floral resource was planted in a small urban residential plot at the University of California, Berkeley Oxford Tract with the goal of attracting local native California bee species to assess emerging patterns of diversity and seasonality. A standard procedure was then used in 2004 to sample the bees and monitor their host flowers. Pollen and nectar resources were abundant and consistently available during spring, summer, and early fall months of that year. Thirty-two bee species representing 17 genera, and five families used these resources through the 2004 season. Urban bees were categorized into three seasonalities: early season, late season, and full season represented by seven, eight, and 17 species respectively. Results of this study indicate that newly-planted urban gardens, which are designed for bees, have the potential to attract diverse seasonal bee taxa if diverse floral resources are provided throughout the growing season. Implications of these finding are discus...

A survey of the bee species and their ornamental host flowers that occur in residential neighborhoods of the cities of Albany and adjacent Berkeley in northern California was conducted from 1999–2003. A simple bee frequency (visitation) count was developed to evaluate the relative attraction of bees to their host flowers. Results of the survey revealed that 76 species of bees, mostly natives, from five families, visited 129 host plants at measurable levels. The most common host plant families were Asteraceae, Lamiaceae, Polygonaceae, Rosaceae, and Scrophulariaceae. Honey bees and all other bee taxa were recorded separately on host plants, and both bee groups were more attracted to California native plants than exotics on a percentage basis. Variable attraction was recorded within native and exotic host plants, and a large part of this variation appears related to where the plants are found in residential areas. In general, the highest bee diversity and abundance was observed in diverse gardens ha...