[Pollinator] Beyond Honeybees: Now Wild Bees and Butterflies May Be in Trouble

Tue May 6 08:45:12 PDT 2014

From: Wired magazine

www.wired.com/2014/05/wild-bee-and-butterfly-declines/
Beyond Honeybees: Now Wild Bees and Butterflies May Be in
Trouble<http://www.wired.com/2014/05/wild-bee-and-butterfly-declines/>

   - By Brandon Keim <http://www.wired.com/author/brandon9keim/>
   - 05.06.14  |
   - 6:30 am  |

By now you probably know about the plight of America’s honeybees: the
collapsed colonies and dying hives, threatening pollination services to
crops and the future of a much-beloved insect.

But it’s not just honeybees that are in
trouble<http://www.wired.com/2013/05/winter-honeybee-losses/>.
Many wild pollinators—thousands of species of bees and butterflies and
moths—are also threatened. Their decline would affect not only our food
supply, but our landscapes, too. Most honeybees live in commercially
managed agricultural colonies; wild pollinators are caretakers of our
everyday surroundings.

“Almost 90 percent of the world’s flowering species require insects or
other animals for pollination,” said ecologist Laura Burkle of Montana
State University. “That’s a lot of plants that need these adorable
creatures for reproduction. And if we don’t have those plants, we have a
pretty impoverished world.”

Compared to honeybees, wild pollinators are not well studied, and their
condition has received relatively little public attention.  Most people
don’t realize that there are thousands of bee species in the United
States<http://www.wired.com/2013/08/beautiful-bees/?viewall=true>.
Even many butterflies are overlooked, with the plight of just a few
species, particularly monarchs, widely recognized.

'Species that used to be in all our yards are dropping out.'

Wild bees and butterflies are out on the landscape, making them difficult
to count, and a lack of historical baselines makes it challenging to detect
long-term trends. Slowly but surely, though, results from field studies and
anecdotal reports from experts are piling up. They don’t paint a pretty
picture. Many pollinator populations seem to be dwindling.

According to a recent survey organized by the Xerces Society, an
invertebrate conservation group, nearly one-third of North American
bumblebee species are
declining<http://www.xerces.org/wp-content/uploads/2011/12/BBSG-2013-Annual-Report.pdf%20>.
Other studies have reported similar
trends<http://www.duluth.umn.edu/biology/documents/MaKarrall2_000.pdf>,
documenting dramatic declines in once-common species such as the American
bumblebee. If that’s happening to bumblebees, says Xerces Society executive
director Scott Black, it’s quite possible, even likely, that others are
hurting, too.

“There’s very little information status on most of the bees other than
bumblebees, but if you look at the life histories of these groups, many are
likely even more sensitive to the disturbances leading to the declines,
such as pesticides and habitat loss,” Black said. “Although we don’t know
what’s going on with all bees, I think we could be seeing real problems.”

Among other pollinators, iconic monarch butterfly declines are well
documented: Their numbers are now at a small fraction of historical
levels<http://www.nytimes.com/2013/11/24/sunday-review/the-year-the-monarch-didnt-appear.html>.
And entomologist Art Shapiro of the University of California, Davis spent
most of the last four decades counting butterflies across central
California, and found declines in every
region<http://onlinelibrary.wiley.com/doi/10.1111/ele.12236/pdf>.
These
declines don’t just involve butterflies that require very specific habitats
or food sources, and might be expected to be fragile, but so-called
generalist species thought to be highly
adaptable<http://www.pnas.org/content/early/2010/01/14/0909686107.abstract>.
Many other entomologists have told Black the same thing.

“Species that used to be in all our yards are dropping out, but nobody’s
monitoring them,” Black said.
 Plenty of blame to go around

Some of the factors behind the declines have also been implicated in
honeybee die-offs. Like honeybees, wild pollinators are sensitive to
pesticides, including neonicotinoids, an enormously popular class of
insect-killers used in most major crops that has been linked to bee
deaths<http://www.wired.com/2012/03/neonicotinoids-bee-collapse/>
.

Their use has been restricted on farms in the European
Union<http://news.sciencemag.org/europe/2013/04/european-commission-goes-ahead-controversial-pesticide-ban?rss=1>but
continues on U.S. farms. They’re also used even
more intensively in nurseries and
gardens<http://www.wired.com/2012/04/neonicotinoids-gardens/>.
What’s more, says Black, instructions on minimizing honeybee harm from
pesticides, such as spraying them in the morning, may end up targeting
other pollinators.

It’s difficult to quantify the harms caused by pesticides—not just
neonicotinoids, but dozens of other chemicals, their effects varying by
dose and combination—but “it’s logical to think they’re having some kind of
effect,” said biologist Claire Kremen of the University of California,
Berkeley. “It’s amazing we see as many pollinators as we do. Those are the
ones who’ve survived this continuous pummeling.”

Significant as pesticide impacts could be, though, they may be eclipsed by
habitat loss. Across the United States, pollinator habitat is disappearing
at rates usually reserved for descriptions of Amazon rain forest
deforestation. This is most striking in the Midwest, where more than 36,000
square miles of wetlands and
prairie<http://www.ewg.org/research/going-going-gone>—an
area larger than Indiana—has been converted to cropland since 2008.

Farms don’t need to be bad for pollinators. The wetlands and drainage
ditches of California’s rice fields provide valuable food and shelter to
butterflies, Shapiro says. But in the Midwest and elsewhere, the widespread
use of herbicide-resistant crop varieties has allowed farmers to apply
herbicide more intensively than ever. It’s now possible to wander a corn
farm for days without seeing a single
bee<http://www.npr.org/blogs/krulwich/2012/11/29/166156242/cornstalks-everywhere-but-nothing-else-not-even-a-bee>
.

Add urban and suburban development that produces landscapes of chemically
maintained, regularly mowed lawns and roadsides, and “habitat loss is
generally thought to be the most important factor driving bee declines,” wrote
researchers in 2010<https://www.ufz.de/export/data/1/22686_Potts_et_al_2010.pdf>
.
  Averting disaster

What are the long-term consequences of pollinator loss? Presently it’s hard
to say. In a given locale, losing a few species might have little effect,
as others will take over their ecological role. Lose enough, though, and a
tipping point might be
reached<http://onlinelibrary.wiley.com/doi/10.1111/ele.12236/abstract>,
resulting in a collapse of pollinators and the plants that rely on them to
reproduce.

“You can use the example of an airplane: Start to undo some rivets and
screws, and it’s still going to fly, because there’s still redundancy in
the system,” said Burkle. “But at some point it begins to fall apart.”

[image: The interaction network of flowering plants (top) and pollinators
(bottom) in an Illinois forest fragment. Black lines are relationships that
have remained intact since the late 19th century; red and blue lines are
relationships that have been lost. Image: Burkle et
al./Science]<http://www.wired.com/wp-content/uploads/2014/05/burkle_bee_network.jpg>

The interaction network of flowering plants (top) and pollinators (bottom)
in an Illinois forest fragment. Black lines are relationships that have
remained intact since the late 19th century; red and blue lines are
relationships that have been lost. *Image: Burkle et al.
<http://pages.wustl.edu/files/pages/imce/knightlab/burkle2013science.pdf>/Science*

It’s not yet possible to predict where that point will be, Burkle said, but
stresses are already evident. In a 2013 *Science* paper, Burkle and
colleagues described a 50 percent decline in bumblebee
species<http://pages.wustl.edu/files/pages/imce/knightlab/burkle2013science.pdf>in
an Illinois forest. They also plotted network graphs of historical and
present-day interactions between bees and plants. The comparison (above)
shows a dramatically shrunken web of relationships.

Tipping point or not, such patterns could eventually translate into
agricultural losses. Though most farmers rely on commercial honeybees, wild
pollinators in the U.S. still provide an estimated $14.6 billion worth of
pollination services
<http://www.masterbeekeeper.org/pdf/pollination.pdf>every year. The
oft-cited figure that one
in every three bites of food was
pollinated<http://berkeley.edu/news/media/releases/2006/10/25_pollinator.shtml>includes
not just honeybees, but all pollinators.

'Anybody can do something for pollinators.'

Human diets aside, pollinators put food in the mouths of animals, too, and
cultivate our landscapes. Nature’s verdancy is very much a result of
countless billions of pollinators flying from flower to flower in an
unceasing hum of activity.

“If there was a loss of pollinators,” said USDA entomologist Terry
Griswold, “that would have a cascading effect in terms of forage for a good
proportion of the biota.” In less technical terms, most of what lives
relies on pollinated plants.

If the situation seems grim, though, solutions do exist. Researchers like
Kremen and the University of Maine’s Frank Drummond have demonstrated the
economic value of creating pollinator-friendly habitat on
farms<http://www.esajournals.org/doi/abs/10.1890/12-1051.1>.
Others have shown that it’s possible to get industrial-scale yields while
using a minimum of pesticides and
herbicides<http://www.wired.com/2012/10/big-smart-green-farming/>
.

Kremen noted that costs of helping pollinators are presently borne by
farmers, who often want to help but can’t afford it. “Our government has to
step up and provide support for food growers to do this,” she said. The
USDA did recently start a pollinator habitat restoration
program<http://bigstory.ap.org/article/usda-spending-3m-feed-honeybees-midwest>;
it’s still small, but it’s a beginning.

The public can also play an important role. Griswold recommended that
homeowners leave at least a bit of lawn unmowed—those so-called weeds are
habitat and forage for pollinators—and cut back on herbicide and pesticide
use. Even those small steps, he said, are quite helpful. At a larger scale,
conservation groups like Monarch Watch are working to create pollinator
habitat along the butterfly migration
route<http://www.monarchwatch.org/waystations/>,
a project that will require the participation of thousands of people.

“I would like to see communities get together to have butterfly garden
corridors running through them,” Shapiro said. “If you get five households
on a city block, you’ve got a corridor.”

“If we’re going to deal with these problems, we need to have everybody
taking action,” Black said. “In the past, I worked to get wilderness
designated—with salmon and spotted owls and wolves, with old growth and
wild rivers. That’s different than what I do now, because anybody can do
something for pollinators.”
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