It sounds like something out of a science fiction movie—or nightmare: millions of honeybees suddenly dying off, their bodies never found. Scientists have named the phenomenon “Colony Collapse Disorder,” but they aren’t united on the reason. Theories abound as to the cause of the mass die-off, ranging from the unlikely (cellphones affecting bees’ navigational abilities) to the more plausible though still debated (widespread pesticide use).
Recently, researchers identified a virus (Israeli acute paralysis virus) present in CCD-infected bees, though a causal link has not been verified. Estimates vary, but CCD has resulted in losses of 30 per cent of managed honeybee colonies in the U.S., with unexplained losses being reported in Canada over several years.
Much of the recent focus has been on the state of honeybees (of the genus Apis), a non-native species of crucial importance for the pollination of agricultural crops—everything from apples to onions. Colonies of honeybees are trucked across the U.S. and between Canadian provinces to pollinate flowers and ensure fruit and seed set in commercial crops. The economic value of bees’ pollination services is estimated at $14 billion annually in the U.S. alone; approximately one-third of the continent’s food supply comes from plants that require insect pollinators.
Overshadowed by the press coverage of honeybees, however, is the decline of important pollinators such as native bees in Canada. “We’re losing species of wild bees,” alerts Peter Kevan, a professor at Ontario’s University of Guelph, and an entomology and botany expert. “Two native bumblebee species that used to be the most common bees in Ontario and one species out West all seem to be in massive decline, and may be extinct in some of their habitats already.”
Sheila Colla, a doctoral candidate at York University in Toronto, has been studying populations of native bumblebees (Bombus spp.) in Eastern Canada, and her research confirms significant losses. “Several bee species in southern Ontario show evidence of decline over the past 30 years,” says Colla. Her findings echo those of a 2006 U.S. report by the National Academy of Sciences called Status of Pollinators in North America, which concluded that “Long-term population trends for several wild bee species (notably bumblebees) and some butterflies, bats and hummingbirds are demonstrably downward.” In fact, as far back as 1995, pollinators—there are more than 1,000 species of pollinating insects in Canada including bees, wasps, flies, beetles, moths, butterflies—around the world have been under a great deal of stress, as documented in Stephen Buchmann and Gary Nabhan’s book, The Forgotten Pollinators
Citing pesticide use and habitat loss, Kevan maintains that much of the problem stems from “land-use practices.” And this is where gardeners can make a positive difference. As Rachel Plotkin, a biodiversity policy analyst at the David Suzuki Foundation in Ottawa, stresses, “Gardeners can create pollinator-friendly gardens by growing native plants and by eliminating cosmetic pesticide use.” Bob Wildfong, executive director of Seeds of Diversity Canada of Waterloo, Ontario, a non-profit group that encourages the preservation of heritage plants, likewise emphasizes the importance of creating pollinator habitats in home landscapes: “If you want to have a healthy garden—and especially if you have vegetables—then you need insects,” says Wildfong. “The best way to ensure the presence of insects is to have flowers that bloom for the entire season.” Thus, gardeners should plant for sequential bloom, from spring through to autumn.
While planting nectar-rich flowers to attract pollinators (including hummingbirds) is important, Plotkin cautions this is only one piece of the puzzle: “It’s not just about setting up feeding stations for them. Even more important is fostering or restoring healthy, functioning ecosystems, of which pollinators are just one part.” Pointing to the need for much greater biodiversity in home landscapes as a step toward achieving this, Plotkin describes the “sterile lawn” as a “significant blemish on the face of biodiversity.” She advocates for gardens where interactions among plants, animals, soil, micro-organisms and the like are modelled on natural ecosystems.
A recent project embraces this vision, with a focus on pollinators. The City of Guelph is spearheading the creation of the world’s first public park designed specifically for pollinators, called Pollinator Park. One hundred acres of the decommissioned Eastview landfill site in this mid-size Ontario city will be transformed into a meadow—prime pollinator habitat—with grasses and wildflowers to attract insects.
Currently in the planning stages, the project promises to be far-reaching in its impact. “This is an excellent opportunity to increase public awareness and provide environmental stewardship,” says Jyoti Pathak, the Guelph parks planner responsible for overseeing the project. “This will serve as a model worldwide, turning what used to be a garbage dump into a bloom-filled haven for pollinators and birds.”
Arrivederchi aroma
Humans aren’t the only ones finding it hard to stop and smell the roses. Scientists at the University of Virginia have discovered that air pollution can significantly decrease the fragrance of flowers, and thereby impede pollinating insects’ ability to follow a bloom’s scent trail. The researchers believe this decrease could play a factor in the declining population of pollinators, particularly bees, which rely on nectar for food.
The 2008 study found that in less-polluted eras, such as the 1800s, a flower’s scent molecules could travel as far as 1,200 metres. However, in today’s polluted environments, molecules may spread no more than 200 to 300 metres, often making it difficult for pollinators to find blooms. “Air pollution destroys the aroma of flowers by as much as 90 per cent compared to periods before automobiles and heavy industry,” says professor and study co-author Jose D. Fuentes.
Not only are nectar-dependent insects adversely affected, but so too are the flowers, which rely on pollination to proliferate. —Sandra MacGregor
Bee helpful
What you can do to aid pollinators:
- Plant a diversity of nectar- and pollen-producing species that provide blooms from early spring through fall.
- Include indigenous plants.
- Avoid the use of pesticides.
- Include larval host plants for butterflies (see “Plants to Attract Butterflies” on page 58 for a list).
- Join Pollination Canada’s Citizen Science project and monitor the pollinators that visit your garden (see pollinationcanada.ca).
- Support the North American Pollinator Protection Campaign (see nappc.org).
Bee-attracting plants
Spring:
Serviceberry (Amelanchier spp.) from Zone 2
Dogwood (Cornus spp.) Zone 2
Wild strawberry (Fragaria virginiana) Zone 3
Wild geranium (Geranium maculatum) Zone 4
Oregon grape (Mahonia aquifolium) Zone 5
Redcurrant (Ribes sanguineum) Zone 6
Violet (Viola canadensis) Zone 4
Summer:
Hyssop (Agastache scrophulariifolia) Zone 5
Sunflower (Helianthus spp.)
Blazing star (Liatris spicata) Zone 4
Bergamot (Monarda fistulosa) Zone 4
Black-eyed Susan (Rudbeckia hirta) Zone 3
Broad-leaved stonecrop (Sedum spathulifolium) Zone 6
Stiff goldenrod (Solidago rigida) Zone 4
Culver’s root (Veronicastrum virginicum) Zone 3
Want to give your pollinating bees a place to stay? Build a bee box...
