2009-06-14 "Home gardeners can help pollinators; How to turn your garden into a paradise for pollinators" by Erle Nickel from "San Francisco Chronicle"
As Bay Area gardeners wander nursery aisles carefully choosing flowers and vegetables for their treasured patches of dirt, they need to keep more in mind than pretty colors and summer salads. Consider the honeybee. And butterflies, moths and beetles, even flies.
These pollinators are dwindling in number and the efforts of home gardeners are needed to help change that course.
"Honeybees disappearing." "Commercial crops endangered due to colony collapse disorder." The headlines have become familiar, and the dangers they trumpet are real.
It is estimated that pollinators are needed for reproduction of 75 percent of the Earth's flowering plants, and in North America honeybees enable production of more than 90 commercially grown crops, according to the National Academy of Sciences.
UC Davis entomologist Robbin Thorp, an expert on native bees, says the Western bumblebee was once common from Monterey County to southern British Columbia. "They are virtually undetectable in those areas now," he said. "We're disturbing, destroying and altering the habitat where the native pollinators exist. Urbanization and extensive use of pesticides are major causes."
These are reasons enough to take steps to reverse the trend in declining pollinator populations, but as Laurie Davies Adams, executive director of the Pollinator Partnership in San Francisco, says: "We need to examine the larger picture when it comes to the study of pollinators. Planting native plants for pollinators strengthens local habitats, bolsters watersheds and helps local fauna, all of which contribute to healthier national and international ecosystems." After all, she said, pollinators travel through the landscape without regard to property ownership or borders.
Resources and tools -
* The Pollinator Partnership is a nonprofit organization working with science, government and environmental groups and providing educational resources and tools to gardeners, farm owners and states.
* One of the more helpful resources on the group's Web site is a ZIP code locator to identify which pollinators and plants populate specific microclimates. The group's goal is to restore biodiversity to local and national landscapes, with a focus on adding native and pollinator-friendly plants.
* As agriculture and urban development have led to habitat fragmentation and loss, the group has expanded its work with the state's farmers, the USDA's Natural Resources Conservation Service and the U.S. Forest Service.
The group has adopted Bailey's Ecosystems mapping, created by the Forest Service, using its research to understand the connections between climate and vegetation that affect the diversity of pollinators in the environment. Studies of the state's habitat allow private and governmental groups to understand the dangers that threaten both the natural biodiversity of habitat and health of pollinators in our California coastal chaparral forest region.
Political action -
The Pollinator Partnership is active on the political stage as well, playing a significant role in lobbying for a $20 million provision in the farm bill to study colony collapse disorder and other pollination-related matters. It also oversees the North American Pollinator Protection Campaign. This alliance of pollinator researchers, conservation and environmental groups, private industry and state and federal agencies has been instrumental in focusing attention on the plight of pollinators and the need to protect them throughout the United States, Canada and Mexico.
Meanwhile home gardeners can play a vital role by putting out the welcome mat for pollinators (see "Creating the ideal environment").
"By providing the essential habitat requirements - food, water and appropriate shelters - urban gardeners can create corridors that encourage pollinators to visit," Adams said.
Adding a patch to the floral quilt that reinvigorates the local landscape will help ensure a vibrant and diverse environment for animal and human alike.
Creating the ideal environment -
There are simple but important steps even the weekend gardener can take to attract more pollinators to the garden.
-- First, identify common pollinators and the plants they feed on.
-- Plant small stands of these native flowers where possible. Try to plant flowers that bloom at different times of the year so pollinators will have food throughout the year.
-- Consider planting host plants to provide food and habitats for common Bay Area butterflies.
-- Where possible have fresh water sources available. Don't forget to provide places of shelter for ground and twig dwelling bees. To continue to survive, bumblebees need habitats such as abandoned rodent burrows for their nests and queen hibernation sites.
-- Avoid use of pesticides and herbicides. They can be harmful to beneficial insects such as pollinators, the wildlife that depend on the plants they pollinate, not to mention the health and safety of humans. Consider using an integrated pest management system to control pests.
-- The Pollinator Project provides a variety of information and educational tools, connections to all the North American Pollinator Protection Campaign partners, specific ways to help the pollinators cause, and free products like pollinator posters. pollinator.org.
-- Find the California Coastal Chaparral Forest chart at links.sfgate.com/ZHHE
-- "The Forgotten Pollinators," by Steve Buchmann (Island Press; 1997)
Meet the pollinators -
Specific pollinators and plants have evolved to serve each other. The hummingbird, for example, is uniquely qualified to pollinate tubular flowers. Here are familiar local pollinators and the plants they feed on. Seek them out at your local nursery.
There are more than 4,000 species of native ground and twig nesting bees in the United States, 60 to 90 of them in Northern California. With increased habitat, bees could play an even more vital role in crop and flower pollination.
Other valuable native bee pollinators include the solitary California carpenter bee, which nests in wood, and the metallic sweat bee, which builds underground nests.
Bay Area favorites -
-- Honeybee (Apis mellifera)
-- Western bumblebee (Bombus occidentalis, pictured)
-- Yellow-faced bumblebee (Bombus vosnesenskii)
-- California carpenter bee (Xylocopa californica)
-- Metallic sweat bee (Agapostemon sp.)
Plants they love -
-- Common sunflower (Helianthus annuus)
-- Cosmos (cosmos spp.)
-- Mountain mint (Pycnanthemum incanum/montanum)
-- Cyrilla racemiflora (a good container plant)
-- Woolly blue curls (Trichostema lanatum, pictured)
Butterflies and moths -
The Bay Area provides a habitat for a host of butterflies and moths. Butterflies such as the anise swallowtail, red admiral, painted lady and common buckeye are attracted to gardens and woodlands containing brightly colored flowers that are flat enough to land on, as well as water sources and open spaces such as rocks or earth to sun themselves on.
Moths are attracted to sweet-smelling, pale-colored flowers that open in the late afternoon or evening.
Loss of native habitat affects butterflies in two ways. Plants that serve as host plants, such as milkweed, which the monarch butterfly needs to survive, are less available. And food sources for a variety of butterflies have become diminished or bloom out of sync with their migration schedules, meaning there's less food when they need it most.
Bay Area favorites -
-- Anise swallowtail (Papilio zelicaon, pictured)
-- Red admiral (Vanessa atalanta)
-- Painted lady (Vanessa cardui)
-- Common buckeye (Junonia coenia)
Plants they love
-- Floss flower (Ageratum corymbosum) for attracting clouds of monarchs
-- Lantana (lantana species, pictured)
-- Butterfly bush (buddleia species)
-- Angel's trumpets (datura or brugmansia species) - loved by moths
Hummingbirds are drawn to brightly colored, tubular flowers and those with considerable nectar. Interestingly, hummingbirds can see the color red while bees cannot. Keep an eye out for the Anna's hummingbird (our most frequent resident), the black-chinned hummingbird and Costa's hummingbird.
Bay Area favorites -
-- Anna's hummingbird (Calypte anna, pictured; most common in the San Francisco area)
-- Black-chinned hummingbird (Archilochus alexandri)
-- Costa's hummingbird (Calypte costae)
Plants they love -
-- Western columbine (Aquilegia formosa, pictured)
-- Red larkspur (Delphinium cardinale)
-- Firecracker beardtongue (Penstemon eatonii)
-- Red salvia (Salvia splendens)
-- Woolly blue curls (Trichostema lanatum)
Beetles, flies and bats -
These pollinators are often overlooked but can play an important role. Though not as efficient or choosy as the major pollinators, beetles are known to pollinate large, strong-scented flowers. Flies are generalists of the pollinator world but according to the Pollinator Partnership are more attracted to small flowers situated in shade. Bats aren't active pollinators here in the Bay Area, but in the Southwest they feed on agave and cactus. The long-nosed bat's elongated tongue allows it to extract both pollen and nectar from these sources.