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UK Research on Global Climate Change Gains Notice
By
Terri McLean
 LEXINGTON,
Ky., (Oct. 11, 2006) – As worldwide interest in the topic of
global climate change increases, so, too, has there been an
increase in research related to its effects. Much of that
research has focused on areas where changes are occurring
noticeably and rapidly, such as in the Antarctic.
But researchers at the University of Kentucky College of
Agriculture have completed a nationally hailed research project
that looks at the not-so-noticeable impact of climate change in
an area that has gotten little attention: the forests in
temperate regions.
“Temperate deciduous forests have received much less attention,
but it is necessary to document potential changes in these
systems for equally important economic, aesthetic and ecological
reasons,” said Janet Lensing, who spearheaded the study while a
doctoral student in the UK Department of Entomology.
Specifically, Lensing and her adviser, UK entomologist David
Wise, took a look at how altered rainfall might affect the
decomposition of leaves that litter the forest floor. Even more
specifically, the pair studied how rainfall changes might alter
the indirect effects of a predator – in this case, spiders – in
the decomposition process.
While fungi are the primary decomposers of leaves, fungi are
grazed upon by primitive insects called springtails. Springtails
are the prey of spiders. Together, they make up a complex food
web in which changes at one level can have an indirect effect on
other levels, Wise said.
“One thing ecologists are realizing now is that if we want to
understand how global climate change is going to affect complex
ecosystems … we have to look at how changes in rainfall,
temperatures and so on will affect the complex set of species
interactions in which indirect effects can be very strong,” Wise
said.
To conduct the project, Lensing set up plots in hardwood forests
in the Berea College forest in central Kentucky and manipulated
the rainfall in those plots to mimic the extremes predicted by
global climate change models. She also reduced the number of
spiders from the natural level and then looked at how higher or
lower rainfall amounts affected the spider’s role in the
decomposition process.
“In this experiment, we show that spiders have a completely
different impact on the rate of litter decay depending on
rainfall,” Lensing said. “We found that spiders had little
impact on decay rates under conditions of abundant rainfall.
Under low rainfall conditions, though, spiders accelerated the
rate of litter decay.”
The study’s finding confirmed the hypothesis that Lensing and
Wise developed while planning the project. Results obtained by a
previous doctoral student suggested that spiders may accelerate
litter decay under drought conditions.
“So in one way I was not surprised by the findings,” Lensing
said. “In another way, though, the results of this experiment
were very surprising. The food web in the leaf litter is very
complex and made up of many different groups of arthropods. It
is remarkable to me that a change in rainfall can affect this
one pathway of spiders, springtails and litter decay within this
complex food web and that spiders can impact litter
decomposition differently depending on rainfall amounts.”
The results are significant because they draw attention to “the
fact that predicting the consequences of changes in even one
climatic factor may be difficult due to the combination of
direct and indirect effects that may occur,” Lensing added.
The UK study has become the focus of national attention in
recent days, with results published in The Proceedings of the
National Academy of Sciences (USA) and featured in The New York
Times. Scientific American magazine is also expected to
highlight the study.
“These results are very exciting both in terms of gaining basic
ecological knowledge about this complex food web and also in
terms of exploring the potential consequences of climate
change,” Lensing said. |
Contact: Janet Lensing, 859-257-5838
David Wise, 859-257-4693 |
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of Agriculture, through its land-grant mission, reaches across
the commonwealth with teaching, research and extension
to enhance the lives of Kentuckians. |
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