Marin Master Gardeners
University of California
Marin Master Gardeners

Marin IJ Articles

How to Help our Pollinators

October 22, 2007
Barbara Euser

by Barbara J. Euser

Since 1950, the honey bee population in the United States has declined by 50 percent. The wild, or feral, honey bee population has declined by 70 percent. The general term for this phenomenon is colony collapse disorder. It is caused by a combination of factors including pesticides, parasitic mites, hybridization with aggressive strains of African bees, and loss of forage plants. This may seem merely unfortunate until one considers some additional information.
In June, Senator Barbara Boxer introduced the “Pollinator Protection Research Act of 2007” in the Senate, which includes these statistics:
  • pollination by honey and native bees adds more than $18 billion annually to the value of United States crops;
  • one-third of the food supply of the United States depends on bee pollination, which makes the management and protection of pollinators an issue of paramount importance to the security of the United States food production system;
  • honey bee colonies in more than 23 states have been affected by colony collapse disorder.
If enacted, Boxer’s bill will provide funds for research into colony collapse disorder that will lead to ways to reverse this trend and assist the rebuilding of healthy honey and native bee populations.
Taking a small step to increase the number of honey bees in our community, last spring my husband and I purchased a bee box and a queen and a starter colony of about 4,000 bees. We had done some basic research ourselves and then discovered that a friend of ours had become an avid beekeeper. With our friend Kathy’s help, we became beekeepers ourselves. Placing the hive in the corner of our San Rafael garden, we soon observed the bees returning with their legs loaded with pollen. Over the summer, we managed the frames in the boxes, increasing the area the bees had to store their honey. We are now ready for our first honey harvest. Each generation of bees lives only about seven weeks. Over the summer, our hive has grown considerably. The bees forage over a twelve square mile area, pollinating vegetables and flowers in gardens throughout our community. If keeping bees is of interest to you, there are many informative books and websites. Local associations of beekeepers in Marin and Sonoma counties can provide information and assistance.
If becoming a beekeeper is too much to contemplate, consider doing what you can to assist native bees.
Native bees, included in Boxer’s bill, do not produce honey. But they are very active pollinators, responsible for pollinating nearly one-third of vegetable, fruit and nut crops, as well as almost all wildflowers. Rather than collecting pollen in sacs on their legs as honey bees do, native bees collect pollen on hairs on their stomachs. Thus, they prefer flat, open-faced flowers such as asters and Echinacea. They make their nests in the ground or in wood. Most live as solitary bees, in contrast to honey bees whose colonies number in the thousands. Whereas honey bees were introduced to North America from Europe, native bees originated here.
There are about 4,000 native bee species in North America, and 1,600 in California. Dr. Claire Kremen, assistant professor of ecology and evolutionary biology at Princeton University, has studied native bees in the Central Valley of California. According to an article by Laura Sayre on NewFarm.org, Kremen’s research group monitored native bee populations on organic farms close to wild habitat, organic farms distant from wild habitat and conventional farms distant from wild habitat. They found that 80 percent of organic farms close to wild habitat could rely entirely on native pollinators, whereas only 50 percent of organic farms distant from wild habitat could do so. None of the conventional farms could rely on native pollinators alone. Sayre summarized, “Overall, native bees provided 28 percent of pollination on conventional farms and 60 percent on organic farms.” Increasing wild habitat is clearly important to supporting native bees that can serve as pollinators on farms. Farmers can leave strips of ground unplowed to allow bees to nest, and plant hedgerows of habitat plants to attract native bees.
Native bees have also suffered decimation in recent years. Their wild habitats of native plants have been replaced by farms and sprawling housing developments. Widespread pesticide use, on commercial farms and in domestic gardens, has killed many pests—and millions of native bees. Dr. Gordon Frankie, an entomologist at UC Berkeley, studies how urban gardens can support native bees. To support native bees, a variety of flowering plants is required. Not all bees like the same flowers, and bees require flowering plants throughout the season, spring, summer and fall. As home gardeners, we can play a role in rebuilding the native bee population by planting the varieties of flowers on which native bees thrive—and bolster the health and productivity of our gardens at the same time. As I spent hours this spring and summer watching our new honey bees, I also became aware of the variety of native bees in our garden. I consulted the UC Berkeley website at www.nature.berkeley.edu/urbanbeegardens to learn which plants I should include to attract native bees. I discovered that my garden already includes over a dozen: achillea, ceanothus, echium, erigeron, California poppy, lavender, penstemon, California coffeeberry, salvia, verbena, mint, nepeta, thyme, and rosemary.
To learn more about native bees, how they benefit our gardens, and what we can do to benefit them, join Dr. Frankie at the Marin Master Gardeners Continuing Education event on November 1 at 7 p.m. at the Marin Art and Garden Center. The event is open to the public.

Top of page

Webmaster Email: banielsen@ucanr.edu