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How to protect our imperiled pollinators - includes related article National Wildlife, Feb-March, 1998 by Olwen Woodier

A decline in bees and other pollinators is trouble for the entire country. Here's what you can do about it.

One sunny morning last summer, Hachiro Shimanuki strolled into the backyard garden of his home in Maryland. With camel-hair brush in hand, he stood poised above the drooping yellow blossoms of a tomato plant. Flicking the brush across the inside of a flower, he gently spread pollen, or male reproductive cells, to the stigma, or female part of the plant. This process, known as pollination, is essential for vegetable, fruit and nut production, and is often performed by bees.

"I couldn't find enough pollinators in my small yard so I used the camel-hair brush to pollinate my tomatoes and peppers," says Shimanuki. As head researcher at the U.S. Department of Agriculture's Bee Research Laboratory in Beltsville, Maryland, Shimanuki has charted a 25 percent decline in the United States' population of managed honeybees during the past decade. This decline is being felt far beyond Shimanuki's backyard. Growers of some commercial crops--such as almonds, blueberries, apples, pears, broccoli, squash, pumpkins and cucumbers--are increasingly relying on migrant beekeepers to pollinate their plants. The stakes are high: bee-dependent crops are worth $10 billion a year in the United States.

Domesticated honeybees are not the only pollinators in trouble these days. Many species of butterflies, moths, birds, bats and other mammals are also in retreat, threatening not only commercial crops but a wide range of flowering plants. "Action must be taken to reverse these trends," says Stephen Buchmann, an entomologist at the U.S. Department of Agriculture's Carl Hayden Bee Research Center in Tucson, Arizona. According to Buchmann, only a few of these pollinators (mainly Hawaiian bird species) are protected by the federal Endangered Species Act. "This is simply because the world is focused on the charismatic megafauna--the lions and tigers and bears," he says. "The little things that run the world, including bees, butterflies, bats and hummingbirds, go unnoticed and unprotected until it is sometimes too late."

Not all plants require animal pollination--grasses, for example, have light, dry pollen that is carried by the wind. The pollen of about 80 percent of other flowering plants, however, is too heavy to travel on air currents and needs to be moved from anther to stigma by an external agent. This usually happens by accident, when a bee, butterfly or bird visits a flower in search of a meal of nectar or pollen. Pollen grains from the anthers of the male stamens stick to the pollinator's tongue, head, wings or legs. When the pollinator visits another flower of the same species, it unwittingly deposits the fertilizing pollen on the stigma of the female pistil.

If not for bees, which are responsible for pollinating more flowers than any other creatures on Earth, many plants would be unable to set and produce fruits or seeds. "Every third bite of food we eat, our clothing--cotton and flax--plus many beverages and some medicines come directly from the pollinating activities of these animals," says Buchmann, coauthor of the recently published book The Forgotten Pollinators.

Honeybees--imported from Europe in the 1600s and managed by beekeepers--are the most important pollinators, according to Shimanuki. "They pollinate over 90 cultivated crops," he says. But there are an estimated 4,000 to 5,000 species of native bees in the continental United States--including bumblebees, carpenter bees, sweat bees, leafcutter bees, alkali bees and mason bees such as the blue orchard bee--that also play an important role. Many of them are specialists that pollinate a single plant species within short distances of their nests. This makes their work focused and fast: Four blue orchard bees can pollinate one apple tree in the same time as hundreds of honeybees. Besides being fast and efficient, many specialists perform their magic early in spring when the honeybees are not as active.

But the native bees and other pollinators are suffering from the effects of human disruption of their habitats, according to Buchmann and Gary Paul Nabhan, his collaborator on The Forgotten Pollinators. One of the major reasons for their decline is loss of native plant habitat to shopping malls, business corridors, parking lots and housing developments. Another factor is the extensive use of pesticides (which often kill pollinators as well as pests) on farmlands, in suburbia and in woodlands. In addition, native vegetation and prairies filled with wildflowers (which many native pollinators depend on to feed themselves and their young) have been replaced with pasture grasses for cattle ranching and vast plantings of single-species crops.

All of these actions have resulted in broken "nectar corridors" and habitat fragmentation. Nectar corridors are used by migrating pollinators such as bats, butterflies and hummingbirds. When the pollinators come to an unnatural break in the corridor they move on quickly, arriving at the next group of plants before the flowers have opened and produced nectar. "Now, pollinators have to island hop' across patchy habitats that contain little or no food and dangers [of] highway traffic and pesticide applications," says Buchmann. These fragmented habitats may also be too small to support additional food sources and too far apart to allow for the interchange of pollen. The result of this disrupted interaction is that the plants can't survive without the pollinators and the pollinators (especially specialists dependent on one plant species) can't survive without the plants.

Where native pollinators are suffering from excessive use of pesticides and habitat loss, feral honeybee populations in many states have experienced more than 50 percent losses due to parasites and diseases. Chief among the parasite culprits are two blood-sucking mites--the tracheal mite and the varroa mite--introduced into the United States in the 1980s. Feral European honeybees are also being displaced by aggressive Africanized honeybees, which can take over hives. "They replace the queen with one of their own and in six weeks all the progeny are of African bee stock," says Raymond Williams, an orchard owner in Binghamton, New York, who has been raising honeybees for nearly 50 years.

To help stem the decline of pollinators, Buchmann and Nabhan, director of science at the Arizona-Sonora Desert Museum, recommend that gardeners cut back on pesticide use, create nectar-filled gardens and provide and protect nesting sites. "Home gardeners should, if possible, plant native wildflowers adapted to local/regional soil and climatic conditions," says Buchmann. These and other small steps you can take in your yard can make a big difference for bees, butterflies, hummingbirds and other pollinators. For more details, turn the page.

Olwen Woodier grows a wide range of native and nonnative plants for bees, butterflies and hummingbirds in her backyard garden in northern Virginia.

What You Can Do About the Pollination Crisis

You don't need lots of money and time to help bees, butterflies and other pollinators. One way you can assist them is simply by planting a few flowers. The key, experts say, is choosing varieties that have lots of nectar and pollen. (See "Create a Pollinator Garden" at right.)

"We recommend that people go to local nurseries and look at their regional plant list," says entomologist Stephen Buchmann. "But we don't want people to think they can't plant nonnative flowers. It's just that many hybrid flowers have a nice scent and look attractive but when the bees go down they don't find nectar or pollen."

You don't have to plant acres of seedlings. Even a small border, a few pots or window boxes are helpful. Just plant as many different kinds of flowers as possible to provide a succession of blooms from early spring until the fall. "Any small effort is worthwhile," says Buchmann, "especially if you join in with your neighbors, because although small native bees have shorter flights and won't go far, honeybees, bumblebees and carpenter bees are strong fliers and will fly miles [in search of nectar and pollen]. They will cross over from patch to patch."

If you already have a vegetable garden, introduce some tall plants to attract and slow down pollinators. Sunflowers are good choices, as are climbing varieties such as morning glories, scarlet runner beans, red kidney beans, yellow and purple French beans, garden peas, sweet peas and nasturtiums. Grow them up a fence, trellis or bamboo poles. Bees will also visit plants that require pollination, such as cucumbers, squash, blueberries, pumpkins, melons, tomatoes, peppers and eggplants.

Another method for enticing pollinators is to provide and protect nesting sites, even to the point of encouraging (or at least tolerating) ground-nesting bees and wasps. (See "Build Artificial Nests for Bees" on the following pages.)

Once you've provided a pollinator garden and nests in your yard--or even if you don't--make sure you maintain a safe haven for pollinators. Practice organic gardening methods or use pesticides (preferably those derived from plants or microbes) only when crucial--and then in selective, small ways and always after sundown when the pollinators have retired for the night. Don't spray directly on the blossoms or use systemics, which travel throughout the entire plant. And it's wise not to use dust pesticides, which cling to hairy pollinators and are carried back to their nests. Better to spray bugs with insecticidal soap, or hose them off with a stream of water. Don't use herbicides and insecticides on your lawn, nor water it deeply--these practices can poison or drown ground-nesting pollinators.

It's also important to create a source of food for young pollinators and provide overwintering places for eggs and larvae. To do so, allow a corner of your backyard to naturalize with wild grasses, weeds and wildflowers (including Queen Anne's lace, thistle, burdock, borage, milkweed, evening primrose), and plant extra dill, parsley and carrots, which swallowtail butterfly larvae consume in quantity.

During hot, dry summer months provide water in very shallow birdbaths or pools where pollinators can easily alight around the edges to sip. And because some wasps and bees use mud to build their nests and butterflies like to congregate in muddy puddles, Buchmann recommends allowing a hose or faucet to drip.

And what if you have no garden but you would still like to pitch in? Create window-box gardens or plant in containers on balconies, stoops or rooftops. Join with your neighbors to create and maintain pollinator gardens in vacant lots, public gardens or local schools. Or call your local public works or highway department and offer to help establish or maintain corridors of native plants on median strips.

Create a Pollinator Garden

Choose a location in full sun and, if possible, in the shelter of a wall or large shrubs. Fill the bed with a variety of native plants or a mix of natives and old-fashioned cultivated favorites that are high in nectar. Use long-blooming annuals and shorter-blooming perennials so there is an unbroken sequence of nectar to feed the pollinators from early spring until they hibernate or migrate in the fall.

"Everyone should have fragrant winter honeysuckle. It starts blooming in the middle of winter and blooms to May, feeding bees early," says Suzanne Batra, a scientist at the U.S. Department of Agriculture's Bee Research Laboratory. "I plant tiger and oriental lilies. Hummingbirds love them and also the red Philadelphia lilies. Later there are goldenrods and asters, which are native--but they only grow in disturbed ground, in human clearings."

Hummingbirds arrive in most regions of the United States in April. When spring is cold and blooms are few, feeders filled with nectar water will attract hummingbirds as well as orioles and bees. (In the desert Southwest, bats will also visit feeders at night). These pollinators will also be attracted to a variety of early and long-blooming honeysuckles including native red trumpet honeysuckle and the cultivar Goldflame.

Trumpet or cup-shaped flowers attract hummingbirds, butterflies, moths, bumblebees, carpenter bees, moths and other creatures with long tongues. These plants include lily, cardinal flower, honeysuckle, bee balm, trumpet vine, abelia, beauty bush, scarlet salvia, blue salvia, flowering tobacco, primrose, evening primrose, wiegelia, lily of the valley, single petunia, morning glory, nasturtium, snapdragon, foxglove, fuschia, pineapple and common sages, impatiens, poppies, red clover, scarlet runner bean, sweet peas, squash. In fact, any trumpet-shaped flowers that are red, orange or hot pink and, of course, high in nectar will attract hummingbirds.

Honeybees have somewhat shorter tongues than bumblebees. Even so, they can work a variety of the above flowers and, like butterflies and moths, also feed on tightly packed clusters of tiny flowers. Such shallow blossoms also provide easier access to the short tongues of the smaller native bees, wasps, beetles, blowflies and hoverflies (wasp and bee mimics). These plants include butterfly weed and other milkweeds, abelia, butterfly bush, Joe-pye weed, sweet William, lantana, lilac, thistle, knapweed, viper's bugloss, hawthorn, hydrangea, spirea, goldenrod, phlox, heliotrope, penta, sweet allysum, yarrow, dandelion, staghorn sumac, thymes, mints, oreganos and white clover.

Other favorites include clematis, purple and yellow coneflowers, coreopsis, aster, zinnia, hollyhock, calendula, native sunflower, Mexican sunflower, cornflower, gaillardia, daisies (gloriosa, painted, shasta, ox-eye), blackberry, chrysanthemums, multiflora roses, old-fashioned roses, tomato, eggplant and strawberry.

Trees and shrubs that provide pollen and/or nectar early in the season for butterflies, bees, wasps, moths and other insect pollinators include tulip poplar, dogwood, cherry, plum, pear and other fruit trees, blueberry, barberry, andromeda, azalea, mountain laurel, boxwood, holly, viburnum, daphne, witch hazel, red maple and willow.

Build Artificial Nests for Bees

You may prefer to share your gardens with butterflies and hummingbirds rather than with wasps and bees. However, these potentially stinging insects are paramount to our survival and need to be welcomed into at least a corner of our backyards. Take heart--these pollinators generally won't trouble you if you don't trouble them. (If you are allergic to insect stings, or suspect you might be, consult your doctor before building bee nests.)

One solution to managing wild bee colonies is to attract them to areas far from decks, patios and playing areas. You can do this by creating artificial nesting sites out of wood. Biologist Gary Paul Nabhan suggests drilling different-sized holes into blocks of softwoods, such as sugar pine and elderberry. "An astonishing variety of native bees and wasps can be accommodated that way," he says.

Adds beekeeper Raymond Williams: "There are not enough natural holes for wild bees, but you can increase their numbers by providing houses." He takes 4 x 4-inch blocks in lengths of at least 8 inches and drills 6 to 10, 6-inch-deep holes of 1/8 to 3/4-inch diameter. So the bees can chart a steady approach to their entrances, the blocks should be secured in a rigid position and attached under the eaves directly against the house or an outbuilding on the northeast side. They can also be nailed onto a tree in the shade or onto posts under shelters. "You don't want direct sun; it will cook them or they'll hatch too early in the spring when there's nothing for them to eat," warns Williams. He also recommends covering the front of the shelters with bird netting to keep out birds.

Bumblebee nests can be made of Styrofoam coolers or wooden boxes stuffed with upholsterer's cotton, which the bees need for insulation, according to Buchmann. To construct, drill a few drain holes in the bottom of a cooler or closed box, create a hole into which a piece of garden hosing will fit snugly and place the box six to 12 inches underground. Connect the nest entrance hole to the surface with a section of the hose.

One of the easiest ways to provide nests for hornfaced and stem-nesting native bees is to tie bundles of dried pithy stems (sumac, goldenrod, bamboo) or to stuff cans with straws and suspend them five to six feet off the ground in shaded protected sites. "If done in the spring, native bees will find these holey habitats and begin nesting," says Buchmann. "You will reap the benefits of bigger and better-tasting fruits and vegetables."

Bees will also turn stumps, dead branches and rotting trees into nesting habitats. The tunnels created in dead wood by beetle larvae are particularly attractive to nesting female leafcutter and mason bees.

What if you find a bee colony too near the house and need to remove it? Don't resort to chemical warfare--check your phonebook or call your county extension agent for the name of a local beekeeper. Most are willing to remove a colony (sometimes for a small fee) or they'll tell you how to smoke the bees out.

For more information, phone the Forgotten Pollinators Campaign at 520-883-3006; e-mail them at fpollen@azstarnet.com. For more information about gardening for wildlife, write: Backyard Wildlife Habitat Program, NWF, 8925 Leesburg Pike, Vienna, Virginia 22184. COPYRIGHT 1998 National Wildlife Federation COPYRIGHT 2000 Gale Group

Olwen Woodier "How to protect our imperiled pollinators - includes related article". National Wildlife. FindArticles.com. 19 Apr, 2011. http://findarticles.com/p/articles/mi_m1169/is_n2_v36/ai_20334600/ COPYRIGHT 1998 National Wildlife Federation COPYRIGHT 2000 Gale Group