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  • From: Lawrence London <lfljvenaura@gmail.com>
  • To: permaculture <permaculture@lists.ibiblio.org>
  • Subject: [permaculture] Wild Bees Are Good For Crops, But Crops Are Bad For Bees : The Salt : NPR
  • Date: Thu, 14 May 2015 22:03:16 -0400

Wild Bees Are Good For Crops, But Crops Are Bad For Bees : The Salt : NPR
http://www.npr.org/sections/thesalt/2013/03/01/173167125/wild-bees-are-good-for-crops-but-crops-are-bad-for-bees

Some of the most healthful foods you can think of — blueberries,
cranberries, apples, almonds and squash — would never get to your plate
without the help of insects. No insects, no pollination. No pollination, no
fruit.

Farmers who grow these crops often rely on honeybees
<http://www.npr.org/blogs/thesalt/2012/02/14/146872577/why-california-almonds-need-north-dakota-flowers-and-a-few-billion-bees>
to do the job. But scientists are now reporting
<http://www.sciencemag.org/content/early/2013/02/27/science.1230200> that
honeybees, while convenient, are not necessarily the best pollinators.

A huge collaboration of bee researchers, from more than a dozen countries,
looked at how pollination happens in dozens of different crops, including
strawberries, coffee, buckwheat, cherries and watermelons. As they report
in the journal *Science,* even when beekeepers installed plenty of hives in
a field, yields usually got a boost when wild, native insects, such as
bumblebees or carpenter bees, also showed up.

"The surprising message in all of this is that honeybees cannot carry the
load. Honeybees need help from their cousins and relatives, the other wild
bees," says Marla Spivak
<http://www.entomology.umn.edu/People/GradFaculty/Spivak/>, a professor of
entomology at the University of Minnesota. "So let's do something to
promote it, so that we can keep honeybees healthy and our wild bee
populations healthy."

Unfortunately, a second study
<http://www.sciencemag.org/content/early/2013/02/27/science.1232728>, also
released in *Science* this week, makes it clear that wild bees aren't
having an easy time of it.

That study essentially follows in the century-old footsteps of Charles
Robertson <http://news.wustl.edu/news/Pages/25037.aspx>, "one of America's
great scientists that nobody knows about," says Laura Burkle, an ecologist
at Montana State University.

Robertson taught biology and Greek at Blackburn College in Carlinville,
Ill., and he was fascinated by the close connection between insects and
flowers. He spent years in the forests around Carlinville, carefully noting
which insects visited which wild flowers at what time of year.

Burkle and Tiffany Knight
<http://www.biology.wustl.edu/faculty/knight/knightcv.html>, a colleague at
Washington University in St. Louis, went back to Carlinville to see how
much of the ecosystem that Robertson observed still exists today.

Much of the forested area around the town has been converted into fields of
corn and soybeans — or suburbs. In the fragments of forest that remain,
Burkle and Knight found all of the flowering plants that Robertson recorded
in his notes a century ago. Of the 109 species of bees that Robertson saw,
though, just over half seemed to have disappeared from that area.

"We don't know why," says Burkle.

One possibility might be a loss of nesting sites for these bees. But a
changing climate may also play a role.

The bees that disappeared tended to be species that depended on just a few
kinds of flowers for food. For those bees to survive, their preferred
flowers have to be blooming when the bees start flying and need food. The
warming trend might have thrown off that timing.

In fact, Burkle says, if you map the interactions between flowers and bees,
they seem more tenuous now. Some flowers may get visited by just one or two
kinds of bees, and maybe just for one week.

"I don't know that these systems can take a lot more environmental change
without something drastic happening," she says.

Many bee researchers are trying to figure out how to help those native bees
— and how to help farmers who benefit from them.

Claire Kremen <http://nature.berkeley.edu/kremenlab/>, a conservation
biologist at the University of California, Berkeley, who's a co-author of
the first study in *Science,* says one of the biggest problems for wild
bees is the agricultural specialization that has produced huge fields of
just one crop.

The almond groves of California, for example, are a sea of blossoms in
February. It's a feast, as far as the eye can see, for honeybees that come
here from all over the country.

"But for the rest of the year, there's nothing blooming," she says.

That means there are no bees. "In fact, in places where we have very large
monocultures of almond, we don't find any native bees anymore," Kremen says.

Planting other flowers in and around these almond groves, maybe as
hedgerows, blooming all summer long, would help, she says.

Even better would be farms with smaller fields, and lots of different crops
flowering at different times. Wild bees, Kremen says, need diversity.



  • [permaculture] Wild Bees Are Good For Crops, But Crops Are Bad For Bees : The Salt : NPR, Lawrence London, 05/14/2015

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