![Grassland with grazing cattle. Link to photo information](https://webarchive.library.unt.edu/eot2008/20080921122944im_/http://www.ars.usda.gov/is/graphics/photos/may99/k1223-19i.jpg)
Researchers have begun a new long-term study to
investigate effects of climate change on rangeland vegetation. Click the
image for more information about it.
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Global Warming May Lower Grassland Quality
By Rosalie Marion
Bliss
May 30, 2007 Rising atmospheric carbon dioxide (CO2)
concentrations and air temperatures may lead to an increase in plant
production, but a gradual decline in soil carbon and nitrogen. That's according
to study findings reported by Agricultural Research Service (ARS) and Colorado State University (CSU) scientists in the April issue of
New
Phytologist.
The findings were the result of combined modeling and experimental exercises
that explored the impacts of both warming and rising atmospheric CO2 on the
ecology of native Great Plains grasslands. The results supported findings from
the group's earlier studies, which indicated that future environmental changes
could lead to lower nitrogen concentrations in forage grasses. That condition
could negatively affect animal performance, since grazing animals need
nitrogen-rich vegetation to facilitate digestion.
Plant physiologist
Jack A.
Morgan and colleagues at the
ARS
Rangeland Resources Research Unit cooperated with the study's lead author,
William Parton of CSU. The scientists are based in Fort Collins, Colo.
The modeling experiment exercise was designed to test the responses from a
new experiment just begun in southern Wyoming, the Prairie Heating and CO2
Enrichment, or PHACE study. The research team has spent two years developing
the PHACE study's infrastructure, while the study itself will run for 5 to 10
years.
The scientists tailored an ecosystem model at the PHACE experiment
sitebased on the earlier experimental resultsto help them
investigate the effects of changes in climate and atmospheric CO2 in relation
to carbon and nitrogen cycling.
A decline in forage quality of the grasslands of eastern Colorado and
Wyoming would have a negative effect on not only livestock, but also native
animals that have grazed there for thousands of years. The modeling exercise
boosted researchers' confidence in the methods being used to assess ecosystems
at the PHACE climate change experiment site.
ARS is the U.S. Department of
Agriculture's chief scientific agency.