November 25, 2013 at 4:04 am #1329MikeKeymaster
Thursday, October 19, 2006 (SF Chronicle)
Loss of species that pollinate is cause for global alarm, researchers say
Juliet Eilperin, Washington Post
Birds, bees, bats and other species that pollinate North American plant
life are losing population, according to a study released Wednesday by the
National Research Council. This “demonstrably downward” trend could damage
dozens of commercially important crops, scientists warned, because
three-fourths of all flowering plants depend on pollinators for
American honeybees, which pollinate more than 90 domestic commercial
crops, have declined by 30 percent in the past 20 years. This poses a
challenge to agricultural interests such as California almond farmers, who
need about 1.4 million colonies of honeybees to pollinate 550,000 acres of
their trees. By 2012, the state’s almond farmers are expected to need bees
to pollinate 800,000 acres.
Gene Robinson, an entomologist at University of Illinois, Urbana-Champaign
and one of the 15 researchers who produced the report, said U.S. farmers
had to import honeybees last year for the first time since 1922,
underscoring the extent of the problem.
“The honeybee industry is at a critical juncture,” Robinson said. “The
time for action is now.”
A number of factors have cut pollinators’ numbers in recent decades, the
researchers said. Pesticides and introduced parasites such as the varroa
mite have hurt the honeybee population. Bats, which carry pollen to a
variety of crops, have declined as vandalism and development destroyed
some of their key cave roosts.
John Karges, a Nature Conservancy conservation biologist who works with
the federally endangered Mexican long-nosed bat in west Texas, said the
bat’s U.S. population fell from 10,000 in 1967 to 1,000 in 1983. The
species feeds on nectar from the agave plant, which can be used to produce
a sweetener as well as tequila.
“This bat is rare and suspected of declining rangewide,” said Karges,
noting that it can now be spotted only at one protected cave site in Big
Bend National Park. “I don’t think anyone’s looking at it annually or
The declines have been gradual and in some instances are hard to quantify,
the committee concluded. But the panel’s chairwoman, entomologist May
Berenbaum of the University of Illinois, Urbana-Champaign, said in a
statement that there is already cause for alarm.
“Despite its apparent lack of marquee appeal, a decline in pollinator
populations is one form of global change that actually has credible
potential to alter the shape and structure of terrestrial ecosystems,”
Animals carry pollen, which they pick up inadvertently while feeding on a
plant’s nectar, and transfer it from one flowering plant to another,
sometimes over significant distances. The process not only boosts plant
production but increases species’ genetic diversity.
Animal pollinators fertilize more than 187,500 flowering plants worldwide.
Scientists believe these plants, called angiosperms, gained ecological
dominance more than 70 million years ago in part because animals help them
disperse their pollen so broadly. Other pollinators include hummingbirds
and butterflies, as well as wild bees.
In many ways pollination works as a chain, said committee member Peter
Kevan, a professor at the University of Guelph in Ontario, in which even
the largest animals depend on small insects.
“Canadian black bears need blueberries, and the blueberries need bees” for
pollination, Kevan said. “Without the bees you don’t have blueberries, and
without the blueberries you don’t have black bears.”
Despite this crucial link, Robinson said, many ordinary citizens fail to
grasp how important pollinators are to food production.
European researchers also have documented serious declines: The diversity
of bee species has declined by 40 percent in the United Kingdom and 60
percent in Holland since 1980. Europeans have more detailed records of
pollinators than Americans, said University of Arizona entomologist
Stephen Buchmann, partly because they have more amateur taxonomists
keeping track of them.
Copyright 2006 SF Chronicle
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