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--></style><title>Not climate alone: Bumblebees take beating on
multiple fro</title></head><body>
<div><font face="Geneva">"We're hitting these animals with
everything," he says. "There's no way you can nail a bee
with neonicotinoids, invasive pathogens, and climate change and come
out with a happy bee."</font><br>
<font face="Arial"></font></div>
<div><font face="Geneva">The loss of bee species could carry
consequences for ecosystems and people. For instance, "plants
that like their pollinators to be pretty loyal" could see
declines in reproduction, says ecologist Laura Burkle of Montana State
University, Bozeman. And given that wild bees help pollinate many
crops, "we play with these things at our peril," Kerr says.
"The human enterprise is the top floor in a really big scaffold.
What we're doing is reaching out and knocking out the
supports."</font></div>
<div><font
face="Geneva">-----------------------------------</font></div>
<div><font face="Geneva" size="+2">Bumblebees being crushed by climate
change</font></div>
<div><font face="Geneva">By Cally Carswell 9 July 2015</font><font
face="Arial"><br>
</font><font
face="Geneva"><u
>http://news.sciencemag.org/biology/2015/07/bumblebees-being-crushed-</u
>climate-change</font><font face="Arial"><br>
</font><font face="Geneva">Science| DOI:
10.1126/science.aac8824</font><font face="Arial"><br>
</font><font face="Geneva"><br>
As the climate changes, plants and animals are on the move. So far,
many are redistributing in a similar pattern: As habitat that was once
too cold warms up, species are expanding their ranges toward the
poles, whereas boundaries closer to the equator have remained more
static.</font><font face="Arial"><br>
</font><font face="Geneva"><br>
Bumblebees, however, appear to be a disturbing exception, according to
a study in Science today. A comprehensive look at dozens of
species, it finds that many North American and European bumblebees are
failing to "track" warming by colonizing new habitats north
of their historic range. Simultaneously, they are disappearing from
the southern portions of their range.</font><font face="Arial"><br>
</font><font face="Geneva"><br>
"Climate change is crushing [bumblebee] species in a vice,"
says ecologist Jeremy Kerr of the University of Ottawa in Canada, the
study's lead author. The findings underscore the importance of
conserving the habitat the insects currently persist in, says Rich
Hatfield, a biologist with the Xerces Society for Insect Conservation
in Portland, Oregon, who was not involved in the study. Where
bumblebees vanish, the wild plants and crops they pollinate could also
suffer.</font><font face="Arial"><br>
</font><font face="Geneva"><br>
To see how global climate change is affecting the bees, the
researchers amassed a data set consisting of some 423,000
observations, dating back to 1901, of 67 bumblebee species in North
America and Europe. Then they mapped large-scale changes in the
species' territories and in their "thermal ranges"-the
warmest and coolest places the bees live. They also built statistical
models to test whether any range shifts were best explained by climate
change, or whether two other factors-changes in land cover and the use
of pesticides such as neonicotinoids, which have been implicated in
smaller-scale bee declines-also played a key role.</font><font
face="Arial"><br>
</font><font face="Geneva"><br>
Overall, they found that some bumblebees have retreated as many as 300
kilometers from the southern edge of their historic ranges since 1974.
The rusty patched bumblebee (Bombus affinis), for instance, has
disappeared from parts of the southeastern United States. Southern
species are also retreating to higher elevations, shifting upward by
an average of about 300 meters over the same time period. Meanwhile,
few species have expanded their northern territories. And it turned
out that climate change was the only factor that had a meaningful
impact on the large-scale range shifts. (Data on pesticide use were
available only in the United States, however, and the study did not
examine whether populations were growing or shrinking.)</font><font
face="Arial"><br>
</font><font face="Geneva"><br>
One clue to the importance of climate: Bumblebee ranges began
shrinking "even before the neonicotinoid pesticides came into
play in the 1980s," says ecologist and coauthor Alana Pindar, a
postdoctoral fellow at the University of Guelph in Canada. She says
the retreat from southern territories is "a huge loss for
bumblebee distributions" and happened surprisingly quickly. The
researchers believe the retreat-and the move to higher elevations-may
reflect the fact that bumblebees evolved in cooler climates than many
other insects that haven't yet lost ground, and so are especially
sensitive to warming temperatures.</font><font
face="Arial"></font></div>
<div><font face="Geneva"><br>
More mysterious is their failure to push north. "What we can
infer is that temperature in the northern latitudes is not what's
limiting their spread," says Ignasi Bartomeus, a researcher at
Spain's Estación Biológica de Doñana in Seville, who was not
involved in the study. Differences in daylight or food could hamper a
march north, or bumblebee populations may simply be too slow-growing
to quickly expand.</font><font face="Arial"><br>
</font><font face="Geneva">Many bumblebees form small colonies, Kerr
explains, limiting their ability to spread quickly. In contrast,
species with high population growth rates are "more likely to be
able to establish a new colony that represents a measurable difference
in geographic range." He notes that one outlier in the study, the
buff-tailed bumblebee (Bombus terrestris), one of Europe's most common
species, is known for its reproductive success and has moved north.
The species "is kind of like the dandelion of the bumblebee
world," he says.</font><font face="Arial"><br>
</font><font face="Geneva"><br>
So far, says Bartomeus, the most common bumblebee species seem to be
the most resilient. But "we have a lot of losers," he
cautions, including species that have specialized habitat
requirements. And climate change could further strain species already
struggling with dwindling habitat and other pressures, Kerr says.
"We're hitting these animals with everything," he says.
"There's no way you can nail a bee with neonicotinoids, invasive
pathogens, and climate change and come out with a happy
bee."</font><br>
<font face="Arial"></font></div>
<div><font face="Geneva">The loss of bee species could carry
consequences for ecosystems and people. For instance, "plants
that like their pollinators to be pretty loyal" could see
declines in reproduction, says ecologist Laura Burkle of Montana State
University, Bozeman. And given that wild bees help pollinate many
crops, "we play with these things at our peril," Kerr says.
"The human enterprise is the top floor in a really big scaffold.
What we're doing is reaching out and knocking out the
supports."</font></div>
<div><br></div>
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<div><font face="Bookman Old Style"
color="#000000"
>==========================================================</font></div
>
<div><font face="Geneva" color="#000000">"Even doubling our
current rate of decarbonisation, would still lead to emissions
consistent with 6 degrees of warming by the end of the century. To
give ourselves a more than 50% chance of avoiding 2 degrees will
require a six-fold improvement in our rate of
decarbonisation."</font></div>
<div><font face="Geneva" color="#000000"><br></font></div>
<div><font face="Geneva" color="#000000">Leo Johnson</font></div>
<div><font face="Geneva" color="#000000">Partner, Sustainability and
Climate Change, PricewaterhouseCoopers</font></div>
<div><font face="Geneva" color="#000000">"Too late for two
degrees? Low carbon economy index" November 2012</font></div>
<div><font size="-1"
color="#000000"
><<https://www.thepmr.org/system/files/documents/Low%20Carbon%2<span
></span>0Economy%20Index%202012.pdf>></font></div>
<div><font face="Bookman Old Style"
color="#000000"
>===================================================================</font
></div>
<div><font face="Bookman Old Style" color="#000000">"Š the serious
meaning in a concept lies in the</font></div>
<div><font face="Bookman Old Style" color="#000000">difference it will
make to someone if it is true."<br>
<br>
William James (1842 -1910)</font></div>
<div><font face="Bookman Old Style" color="#000000"><i>Pragmatism</i>.
Meridian Books, 1955</font></div>
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