A Brief History Of The Urban Bee Project At U.C. Berkeley

What’s the bee picture? Evidence is growing on a global scale suggesting that pollinating insects – including our star pollinators, bees - are declining in numbers. The primary cause of this decline is that, like many other creatures in the natural world, bees are being pushed out of their natural habitat by human development. As more than 30% of our fruit and vegetable crops in the U.S. depend on pollinating insects, and especially bees, this decline in bee populations has important potential consequences for us humans as well as for our surrounding wildlands.

Work in California Wildlands. Our research group at UCB has been working since1987 on documenting bee diversity and bee frequencies on wild California plants in three locations: two in the lower San Joaquin Valley and one in the coastal mountains in upper Carmel Valley. Our goal was to gather some basic information about native bees before the Africanized honey bee (AHB) arrives in northern California. This information could then be used to assess the impacts of AHB on native bees. During the course of this research, we learned a lot about bee sampling methods, bee diversity, bee visits to flowers, and year-to-year variations in bee populations.

Beginnings of the Urban Bee Project. In the late 1990s, Gordon Frankie and Mary Schindler began sampling bees at Albany Hill in collaboration with Barbara Ertter (UCB Herbarium) and Jerry Powell (UCB, Insect Biology). We discovered a modest diversity of bee species on the hill, which sparked our interest as to whether nearby urban areas of Berkeley support a notable diversity of bees. The larger and significant questions were:
1) Can Bay Area urban cities support substantial bee populations despite human development?
2) Can urban areas actually serve as important reservoirs for diverse bee species, especially if humans make some modest adjustments to accommodate and encourage them?
These important questions led us to focus much of our energy in 2001 on urban north Berkeley where we began to observe and sample bees and to document bee diversity and their floral hosts in Berkeley residential and community gardens. With the help of Robbin Thorp (U.C. Davis), who is an expert bee biologist and taxonomist, and two UCB undergraduates, Megan Konar and Jacki Kohleriter, we made several discoveries about bees in urban areas. Some of our most important discoveries so far include the following:
• Of the almost 1,000 ornamental plants we have surveyed for their relative attractiveness to urban bees about 950 are exotic to California and at least 50 are native to California.
• At least 76 species of bees (73 natives and 3 exotics) have been collected from urban residential areas of Albany and N. Berkeley.
• Native California bees are 6 times more likely to visit native California plants than exotics.
• Urban bees are unevenly distributed in urban neighborhoods. Gardens with 10 or more attractive bee plants flowering simultaneously had the highest bee diversity and abundance. By comparison, attractive bee plants that are isolated in gardens attract a lower diversity and abundance of bees.

The Oxford Tract Bee Garden. Our discoveries were so exciting that we decided that we had to have a super “bee garden” of our own on the campus of University of California Berkeley. Using all of the information we gathered from north Berkeley residential gardens, we spent the summer and fall of 2003 planting large patches of flowers most attractive to bees in a section of the U.C. Berkeley Oxford Tract.

Although we started with nothing more than bare dirt, we found that planting the right attractive bee flowers almost immediately began attracting native California bees. Within the first month of planting, we noticed that circular holes were being carved out the leaves of our California rose plants. From our experience with native bees, we know that one genus, the megachilid or “leafcutter” bees, use pieces of leaves to build their nests. Sure enough, on closer observation we discovered that these bees were already making their individual nests around the outer perimeter of the watering basins of the plants.

Our monitoring work in this garden has also produced many interesting, preliminary results. For example, we have already discovered 4 new species of bees that we had not yet collected in other urban Berkeley areas pollinating our flowers. These exciting discoveries are just the beginning as we continue to plant attractive “bee flowers” and monitor bees in the coming year.

Outreach Projects. In the late 1990s, G. Frankie began working with high school volunteers at the Oakland Zoo to teach them about bees in the Oakland hills, how to study and collect them, and how to curate them at UCB. In 2001, work shifted to the urban north Berkeley hills where students learned how to observe and sample bees in a structured program to document bee diversity and floral hosts. This work provided preliminary information on urban bees and some of their host flowers. It also taught us that outreach and education for all levels of audiences – including elementary children and high schoolers – is crucial to protecting and conserving bees.

In the summer of 2003, we began to extend our outreach program to interested urban private residents and schoolteachers. Inspired by a series of presentations and workshops on how to plan and monitor bee gardens we offered during the year, many of the participants have begun to plan (and plant!) their own bee gardens. Next year we will be visiting these experimental gardens on a regular basis with the intent of teaching participants and their students how to monitor bees and to include them as our research partners.