Insects are the most diverse and effective of all animal pollinators; bees, flies, butterflies, moths, wasps, and beetles pollinate about 90 percent of all flowering plants. Bees pollinate about 75 percent of global food crops and are responsible for most of the plant-derived antioxidants, vitamins, and many other essential nutrients in the human diet.
It’s not news that the domestic honeybee (Apis mellifera) is in trouble. Populations are declining due to pesticides, parasites, and disease as well as a threat specific to domestic honeybees, identified in 2007 as Colony Collapse Disorder (CCD), wherein hives die because mature bees leave and do not return. The situation with domestic honeybees has drawn attention to the plight of native bees. Once viewed only as back-up pollinators when honeybees were unavailable, under continuing pressure from CCD, native bees are now recognized as vital to human nutrition and to the native plants they evolved with.
Of the approximately 4,000 species of bees native to North America, most are solitary nesters. Single females lay their egg(s) in brood cells in narrow tunnels that she provisions with pollen and nectar. With no hives needing to be rented, moved, and maintained, native bees provide their pollination services for free. In addition, many native bees emerge earlier in the growing season and fly in worse weather than honeybees, a big plus for rainy regions. Recent studies have shown native bees to be twice as effective as honeybees in producing fruit in 41 different crops around the world. And the presence of native bees alongside honeybees increases pollination efficiency including seed and fruit production in self-pollinating plants.
CCD does not impact native bees and other pollinating insects because they do not make hives, however they, too, are imperiled by environmental threats. But habitat loss is an even greater danger. Fragmentation, or the transformation of large pieces of native habitat into smaller disconnected chunks—the result of modern agriculture, grazing, and urban development—prevents pollinators from traveling between areas to find food and nesting sites. Once viewed only as back-up pollinators when honeybees were unavailable, native bees are now recognized as vital to human crops and wild plants.
Although native and non-native pollinators face many threats, gardeners and other concerned citizens can make a difference. For more inspiration visit public gardens and habitat sites in your area. Arboretums, nature centers, zoos, city and county parks, school and community food gardens, and restored areas often have public areas where pollinators are active. Native plant societies, Audubon groups, and state Fish and Wildlife departments often list sites and local projects.
You can help
Learn about native pollinators. Recognizing different types of pollinators helps gardeners monitor and study the biodiversity in their garden and become deliberate habitat managers. Binoculars and a camera are vital equipment to take into the garden to find and record native bees, as well as the many species of flies, butterflies, beetles, wasps, and other beneficial insects. A hand lens is useful for close-up observations while guidebooks and online resources can help identify mystery animals.
Plant for pollinators. Gardens planted with pollen- and nectar-rich plants create critical habitat connections within an increasingly fragmented environment. Even the smallest plot, container garden, or rooftop planting, can help support native pollinators. If your garden is close to larger private gardens with native plants, organic community gardens, nature reserves, rural parks with native plant populations, or greenways with native trees and shrubs, its effectiveness will extend beyond your property.
Become a citizen scientist. You’ll get to do real science and assist working professionals by monitoring and recording data about animal populations and distribution. Professor Gretchen LeBuhn of San Francisco State University created the Great Sunflower Project in 2008. Original participants were asked to grow sunflowers and collect data about visiting bees; today, observers are invited to record types and count a broad range of pollinators. Project Bumblebee, a program of The Xerces Society, is looking for online participants throughout the country to help track the range of several bumblebee species.
Profile of a pollinator garden
Twenty-five years ago, Julie O’Donald, a Backyard Wildlife Habitat Steward and Master Gardener with a native plant focus, began growing her pollinator paradise in Brier, Washington. Today her garden is abuzz with pollinators from early spring to late fall, demonstrating the following “best practices” recommended by leading conservation organizations:
1. Seek the sun. Position your garden in an open sunny location.
2. Go native. Native plants attract more native pollinators and require less water and added nutrients.
3. Stick to the classics. Old-fashioned non-native ornamentals are more likely to offer pollen and nectar than fancy new hybrids.
4. Avoid invasives. While Buddleia (unfortunately named the butterfly bush) provides abundant food for pollinators, its invasive nature is a threat to the surrounding landscape.
5. Plan and plant for the entire year. Various pollinating insects appear at different times throughout the flowering season. Establish groups of flowering plants that blossom at different times to attract the largest variety of pollinators.
6. Create layers in the landscape. A tree canopy underplanted with shrubs and groundcovers with a mix of grasses, perennials, and annuals supplies food and shelter for a variety of pollinators.
7. Avoid pesticides and other chemicals. Period.
8. Loosen up. Leaf litter, bare soil, the occasional tree snag or pile of branches, and discreet “messy” spots, provide ideal nesting habitat for pollinators.