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<h1><b>Climate change and habitat destruction affect butterfly
populations<br><br>
</b></h1><h2><b>Unique North American study authored by University of
Nevada, Reno, biologist</b></h2>RENO, Nev. – Butterfly populations in
California are declining and, in some cases, moving to higher elevations
in the Sierra Nevada due to climate change and loss of habitat, according
to a study authored by biologist Matthew Forister, a University of
Nevada, Reno assistant professor in the College of Science.<br><br>
"Caterpillars are important herbivores as well as a food source for
small mammals and birds," Forister said. "They play a
significant role in an ecosystem. Butterflies are used as indicators of
the health of the environment worldwide. What's happening here is a
globally recognized pattern, though this study is unique in representing
North America."<br><br>
The study, to be published this week in the <i>Proceedings of the
National Academy of Sciences</i>, is based on 35 years of data collected
by Arthur Shapiro, professor of evolution and ecology at the University
of California, Davis, and analyzed by a team headed by Forister, who was
also a former doctoral student in Shapiro's lab.<br><br>
The analysis of the data found that climate has changed over the past
three decades, with an increase in both maximum and minimum daily
temperatures, shifting some low-elevation butterfly populations to higher
elevations.<br><br>
For example, in recent years the field skipper butterfly seemed to react
to global warming by expanding its range from northern California to
central Washington State and Idaho. Now it's jumped the Sierra and
invaded the western Great Basin, becoming established in California's
Sierra Valley, and in the Carson Valley and near Verdi in Nevada. It also
has been very responsive to spring temperatures, emerging nearly a month
earlier than it did near Sacramento 30 years ago.<br><br>
Forister has been working on analyzing the data for more than five years.
For the data on butterflies to be meaningful, decades of consistent
sampling is required with long-term data sets, he said.<br><br>
The data are based on biweekly butterfly surveys taken at 10 sites in
north-central California encompassing a variety of climates and habitats
from sea level to tree line in the Sierra Nevada and including roughly
150 speciesthe largest data-set of its kind in North America and one of
the two largest in the world. <br><br>
"Art did an unusual thing with his career," Forister said.
"He singlehandedly undertook this data collection, on his own, set a
regular sampling schedule and held to it for 30-plus years. He had
specific questions in collecting this data, but in a way it was
impossible to have predicted what would be found after so many decades of
data collection."<br><br>
Using a battery of statistical approaches, Forister, Shapiro and their
colleagues found that climate change alone cannot account in full for the
deteriorating low-altitude fauna. They used information on land use to
demonstrate that the declines also follow conversion of habitat from
rural to urban and suburban types.<br><br>
Their most significant findings:<br><br>
<ul>
<li>Butterfly diversity (the number of different species present) is
falling fast at all the sites near sea level. It is declining more slowly
or holding roughly constant in the mountains, except at tree line.
<li>At tree line, butterfly diversity is actually going up, as
lower-elevation species react to the warming climate by moving upslope to
higher, cooler elevations.
<li>Diversity among the high-elevation-specialist butterflies is
beginning to fall as temperatures become uncomfortably warm for them.
</ul><br>
"It's a one-two punch, and a lot of lowland species are reeling from
it," Shapiro said, noting that there has been much less habitat loss
in the mountains than in the Central Valley and lower foothills so
far.<br><br>
<div align="center">###<br><br>
</div>
The study, "Compounded effects of climate change and habitat
alteration shift patterns of butterfly diversity," is online at
<a href="http://www.pnas.org">http://www.pnas.org</a>. It was funded by
the National Science Foundation.<br><br>
Additional authors are James Thorne, Joshua O'Brien and David Waetjen at
the UC Davis Department of Environmental Science and Policy; Andrew
McCall at Denison University in Ohio; and Nathan Sanders and James
Fordyce at the University of Tennessee at Knoxville.<br><br>
Forister's Great Basin Bug Lab Web site can be found by clicking here and
his department homepage is at
<a href="http://www.unr.edu/biology/forister.htm">
http://www.unr.edu/biology/forister.htm</a>. Shapiro's online database
can be found at
<a href="http://butterfly.ucdavis.edu">http://butterfly.ucdavis.edu</a>
.<br><br>
Nevada's land-grant university founded in 1874, the University of Nevada,
Reno has an enrollment of nearly 17,000 students. The University is home
to one the country's largest study-abroad programs and the state's
medical school, and offers outreach and education programs in all Nevada
counties. For more information, visit
<a href="http://www.unr.edu">www.unr.edu</a>.<br><br>
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*************************<br>
Scott Hoffman Black<br>
Ecologist/Entomologist<br>
Executive Director<br>
The Xerces Society for Invertebrate Conservation<br>
4828 SE Hawthorne <br>
Portland, OR 97215 <br>
Direct line (503) 449-3792<br>
sblack@xerces.org<br><br>
<i>The Xerces Society is an international, nonprofit organization that
protects wildlife through the conservation of invertebrates and their
habitat. <br>
</i> <br>
To join the Society, make a contribution, or read about our work, <br>
please visit
<a href="http://www.xerces.org/">www.xerces.org</a>.<br><br>
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