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BY LAURA TANGLEY

As European honeybees decline, indigenous bees and other pollinating animals canprovide a backup—with a little help from their human friends

When ecologist Rachel Winfree set out to survey native bees m theDelaware Valley of New }ersey and Pennsylvania, she was not optimistic about her results.Not only is the region far from any known hot spots of bee diversity, such as the U.S. South-west, "New Jersey is also the most densely populated state in the country," says Winfree, anassistant professor in the Department of Entomology at Rutgers University. "I was worriedthat after getting funding and hiring a staff, the project would turn out to be a waste of time."

Her fears were unfounded. "We found bees everywhere," says Winfree—thousands of individuals of 46 differentspecies. More surprising, she and her colleagues discovered that the number of flower visits by these natives was sufficient

to fully pollinate the watermelon cropon 21 of 23 farms in her study region.

Gleaning such data was the goal ofWinfree's work. As European honey-bees decline in a mysterious phenome-non known as Colony Collapse Disor-der (CCD), "I wanted to find outwhether native bees could fill in forthem," she says. While Winfree cau-tions against extrapolating her resultstoo broadly to other crops in otherparts of the country, "if we lost allhoneybees in this region to CCDtomorrow, between 88 and 90 percentof the watermelon crop would befine," she says. "Native bees are pro-viding a backup plan—for free."

Winfree's results, published in Ecol-ogy Letters, have generated an excitedbuzz among native pollinator propo-nents, a diverse group of scientists,

OSMM sp. (right) and Meqachile sp.(above) are among 4,000 bee speciesnative to North America. A study in NewJersey found that native bees fullypollinated the watermelon crop on21 out of 23 farms without help frombeleaguered European honeybees.

conservationists, gardening enthusiastsand others who are sponsoring activi-ties nationwide this June to celebratethe third official National PollinatorWeek. Yet even as they applaud herstudy—and others that show wild beescontribute to the production of cropssuch as blueberries, cranberries, pep-pers, tomatoes, alfalfa and squash—they worry about the welfare of theseunsung natives.

"There has been little effort to doc-ument the long-term status of pollina-tor populations in the United States,"says biologist May Berenbaum, chair-man of the Department of Entomol-ogy at the University of Illinois atUrbana-Champaign. Yet in a 2006National Academy of Sciences (NAS)report, a scientific committee chairedby Berenbaum found that in cases

40 NATIONAL W I L D L I F E

SCIENTISTS ESTIMATE THATIN THE UNITED STATES ALONE,

NA1 IVE BEES PERFORM AS MUCHAS $3 BILLION WORTH OF

POLLINATION SERVICES ANNUALLY

where data do exist, pollinator popu-lation trends are "demonstrablydownward."

Pollinators comprise a diversity ofwild creatures, from birds and bats tobutterflies, moths, beetles, flies andeven the odd land mammal or reptile.But "there's no question that bees arethe most important in most ecosys-tems," says Winfree, who calls theinsects "the 800-pound gorillas" of thepollinator world. Unlike social honey-bees, imported to North America inthe 1600s, the majority of the conti-nent's native bees are solitary, nestingin burrows on the ground or smallholes in wood rather than buildinghives. Worldwide, there are some20,000 bee species, 4,000 of themfound in North America.

Bees and other pollinators areessential to human survival. "Withoutthem, you'd lose most of your plants,and ultimately everything else," saysWinfree. To produce seeds and repro-duce, three-quarters of the world'sflowering plant species rely on animalpollinators. (The others use the lessprecise methods of wind or water totransfer pollen between male andfemale flower parts.) Animal-depen-dent plants include more than two-thirds of the world's crop species,whose fruits and seeds provide morethan 30 percent of the foods and bev-erages we consume. Scientists estimatethat in the United States alone, nativebees perform up to $3 billion worth ofpollination services annually.

Natural ecosystems and theirinhabitants also rely on pollinators.Many North American songbirds, forinstance, feed on the fruits, seeds andberries of plants pollinated by ani-mals. Pollinating insects themselves,especially their plump larvae, provideprotein for adult songbirds and their

fast-growing fledglings. Even thenotoriously carnivorous grizzly beardepends more directly on pollinatorsthan one might expect. According towildlife ecologist Kimberly Winter,NWF's habitat programs manager, insome places between 80 and 90 per-cent of the bear's diet is made up offruits, nuts, bulbs and roots of animal-pollinated plants. On an ecosystemlevel, "losing a pollinator can have adomino effect on countless otherspecies," she says.

To detect pollinator populationtrends, long-term surveys are essen-tial. "The few hardy souls who haveundertaken such studies are findingindisputable evidence of declines,"says Berenbaum. She cites the work ofbiologist Arthur Shapiro, a professorof evolution and ecology at the Uni-versity of California—Davis who hasbeen monitoring butterflies on fixedtransects across the state for the past 37years. Many of the several dozenspecies he has tracked have declined,some dramatically. "Butterflies thatwere once considered utterly commonare going into a tailspin, and no oneknows why," says Shapiro.

In addition to butterflies, the NASreport provides evidence of decline inthree other pollinator groups: hum-

: the work of a leadingexpert on North America's native

bees, see www.nwf.org/waxing.

mingbirds, bats and—especially—bumblebees. A 2008 report from theXerces Society for Invertebrate Con-servation, a nonprofit based in Port-land, Oregon, paints an even bleakerpicture of the familiar, fuzzy insects'fate. Compiling data from more thanthree dozen scientists and "citizenmonitors" across the country, thereport concludes that populations ofthree formerly common species—therusty-patched, yellowbanded andwestern bumblebee—have droppeddrastically over the past decade. Afourth species, Franklin's bumblebee(restricted to coastal Oregon andNorthern California), has only beenseen once in the past several years.

Though the jury is still out on thecause of these declines, the most likelyculprit is an exotic disease introducedby commercially reared bumblebees,says the society's executive director,Scott Hoffman Black. Between 1992and 1994, he explains, queens of thewestern bumblebee, a species com-monly used to pollinate greenhousetomatoes, were shipped to Europe toproduce colonies subsequently shippedback to U.S. farms. Scientists suspectthe bees picked up a fungal diseasefrom European bees, then spread it towild bumblebees across the country ascolonies were moved among commer-cial growers. (All beleaguered speciesare closely related to those that spenttime in Europe.) "Like Native Ameri-cans decimated by smallpox brought inby Europeans, our native bees have noresistance to exotic diseases," saysHoffman Black.

Beyond disease—suspected as amajor cause of CCD in honeybees—blame for pollinator declines runs thegamut: habitat loss and fragmenta-tion, introduced species, pesticides andglobal warming. "But in most cases,

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we don't know," says Laurie DaviesAdams, executive director of the Polli-nator Partnership, a San Francisco-based nonprofit working to raiseawareness about pollinators' plight."We simply haven't paid enoughattention."

There are a handful of exceptions.In the U.S. Southwest, two species ofnectar-feeding bats—the lesser long-nosed and Mexican long-tonguedbat—have declined due to destructionof their roosting caves. Pesticides areimplicated in problems facing severalnative insects, though given the ani-mals' special sensitivity to these chem-icals, "pathetically few toxicity studieshave been conducted, even on honey-bees," says Berenbaum.

Like virtually all living things, polli-nators are also threatened by globalwarming. According to biologistDavid Inouye of the University ofMaryland, some are already beginningto respond to climate change. In theColorado Rockies, for example, he andhis colleagues recently surveyed thealtitudinal distribution of several bum-blebee species at the Rocky MountainBiological Laboratory (RMBL). Theycompared the results with those of asurvey they had conducted along thesame transects as graduate studentsmore than 30 years ago—and foundthat at least one species has shifted itsrange upslope by 1,500 feet.

Pollinators are particularly at risk toindirect effects of warming—whenchanges in temperature or precipita-tion cause shifts in the distribution ofplants or the timing of nectar they pro-duce. In another study at the Coloradolab, Inouye and RMBL colleague BillyBarr found that springtime emergenceof Milbert's tortoiseshell butterfly has

CELEBRAT

The third annual National PollinatorWeek takes place June 22-28, 2009.

To find out how schools, gardenclubs and other groups in your area

are celebrating, and how to getinvolved, go to www.pollinator.org.

HOW TO PLANT FOR POLLINATORS"THE NEAT THING about pollinator conservation is that anyone, from the owner of a

golf course to an apartment dweller with a window box, can do something to help,"

says Scott Hoffman Black, executive director of the Xerces Society for Invertebrate

Conservation. All it takes is to provide appropriate food and habitat for bees, butter-

flies and other pollinating species-and to avoid using the pesticides that harm them.

"Being pollinator-friendly also means you are being wildlife-friendly," says Kim-

berly Winter, NWF's habitats program manager. "And you are creating a sustainable

ecosystem in your own backyard."

Here are a few suggestions to get started:

• To provide pollinators with the best sources of food-and to prevent the spread

of invasive species-choose as many plants native to your region as possible. For

specific recommendations, consult the Pollinator Partnership's free ecoregional

planting guide for your area (www.pollinator.org); all you need is a zip code.

• Select plants that provide a lot of nectar and pollen. Many ornamentals have

been specifically bred to produce little or none of these essential foods.

• Plant a diversity of species so your yard will provide bees, butterflies and other

animals with nectar and pollen from spring through fall. To attract bats and noctur-

nal moths, consider night-blooming plants in addition to day-bloomers.

• Be a "messy" gardener: Leave some patches of unmulched soil and brush piles

that bees, birds and other animals can use to construct nests. Consider building or

purchasing a bee house for wood-nesting wasps and bees.

• During hot, dry periods, provide water in shallow birdbaths or pools where pol-

linators can easily alight. Some wasps and bees need mud to build their nests, and

butterflies like to gather in muddy puddles.

• Do not use pesticides, and encourage your neighbors to reduce their reliance

on these chemicals. According to Winter, more pesticides are used in urban areas

today than in agricultural regions of the United States.

For more tips, check out these sites: www.nwf.org and www.xerces.org.

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A RUSTY-PATCHED bumblebee feeds on bee balm. Once common, this and three otherbumblebee species have declined dramatically over the past decade. Scientists suspect anexotic disease brought in by commercially reared bumblebee queens shipped to Europe togenerate colonies, then brought back to the United States and transported nationwide.

been getting progressively earlier sincethe 1970s. Yet blooming time of theregion's spring wildflowers has notkept up. The findings demonstrate that"pollinators and plants do not respondthe same way to environmentalchanges caused by global warming,"says Inouye. "This means they may losethe synchrony they once had."

Inouye is particularly concernedabout hummingbirds—importantwildflower pollinators—that migratethousands of miles between winterhabitats in the Tropics and breedinggrounds in North America. Researchshows that tropical and temperateecosystems are responding very differ-ently to global warming, and there'sno way a hummingbird wintering inColombia would be able predict whatthe weather is like in Colorado.

Fortunately, there's good news aswell. Thanks to the NAS report andefforts of conservationists, there hasbeen a flowering of appreciation fornative pollinators in recent years.

Concern about European honeybeeshas also helped. CCD, first detectedsoon after the report's publication,had "a silver lining," says HoffmanBlack. "Now many more people

NWF PRIORITY

PROTECTING NATIVEPOLLINATORSThrough its Certified Wildlife Habi-tat™ program, NWF encourages thecreation of habitat suitable for bees,birds, butterflies and other pollina-tors, and educates landownersabout appropriate host plants aswell as the risks of using pesticides.The program also offers all theinformation needed to make yourown yard welcoming to pollinatorsand other native animals. Once youcreate this haven, you can have theproperty certified as an official NWFwildlife habitat. To learn more, go towww.nwf.org/gardenforwildlife.

know that their food is pollinated,and that we need bees and other ani-mals to do that."

Davies Adams agrees that "we seeO

more interest in pollinators than just afew years ago—and more resources tohelp people help pollinators." Amongher organization's activities is the cre-ation of a series of ecoregional plant-ing guides to advise gardeners onplanting native species for insects andother animals. Launched in 2008, thefinal set of 32 guides is scheduled to becompleted this June. The Xerces Soci-ety has published the Pollinator Con-servation Handbool^ as well as a seriesof guides for farmers and managers ofparks, golf courses and other lands.

Perhaps the biggest coup scored bypollinator proponents came last yearwith congressional reauthorization ofthe Farm Bill, which for the first timehas provided specific financial incen-tives to growers who restore habitatfor pollinators and authorized $100million for research on the animals.Winfree has applied for fundingthrough the law to continue workingwith USD As Natural Resources Con-servation Service in New Jersey oncombinations of plants that attract thegreatest diversity of pollinators. Shesuspects the reason she found so manybees in her own study is because theregion's small farms are nestledamong suburban gardens and scrapsof native vegetation, habitats that pro-vide nesting sites and additional foodfor the insects. Similar research con-ducted within vast monocultures ofCalifornia's Central Valley has so farbeen less encouraging.

Winfree, who launched her projectin 2006, obtained equally promisingresults during the 2007 and 2008growing seasons. "When it comes tohuman disturbances like fragmenta-tion," she says, "some bees may turnout to be more robust than some largeranimals like birds and mammals. Andthat would be very good news for con-servation."

Senior Editor LAURA TANGLEYprovidesfood, water and nesting sites for pollina-tors in her own yard.

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