Loss of species that pollinate in California – 10/20/2006

  • November 25, 2013 at 4:04 am #1329

    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,”
    Berenbaum said.

    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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