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