An experiment on the effect of climate change on grazing land in China's
Tibetan Plateau has shown that 26-36 percent of plant species in the
region will decline if global temperatures continue to rise.
Chinese and US scientists conducted the experiments from 1998-2001 in
experimental zoned rangelands where Earth's temperatures are rising
faster than anywhere else.
The findings were shown to Daily Planet Media during a joint meeting of
the International Rangeland Congress and the International Grassland
Congress held last weekend in Hohhot, the capital of the Inner Mongolia
Autonomous Region.
The climate change experiment fenced 900 square meter sites and laid
out 16 plots inducing simulated warming by using open top greenhouses
and grazing through selective clipping.
Each greenhouse measuring 1.5 meters in diameter and 40 centimeters
high were left on the plots year-round, raising the average daily
temperature by 0.6 to 2C degrees.
The experiments revealed medicinal plants had an average annual loss
of 3.9 species from 1999 to 2001, while palatable plants had an annual
average decline of 5.4 species, according to researchers John Harte of
the University of California and Zhao Xinquan, of the Northwest Plateau
Institute of Biology.
The researchers said plants' individual characteristics, such as their
history and root depths, influenced their reactions to the warming. Deep-
rooted species, which lost an average of 20 percent, were less affected
than shallow-rooted species.
The experiments also showed that continued global warming would
lower rangeland quality by decreasing the plants' productivity, while
grazing could maintain or improve rangeland quality by extending the
plants growing season.
"Our findings suggest the rangelands on the Qinghai-Tibet Plateau, and
the pastoralists who depend on them, may be vulnerable to future
climate changes," said Julia Klein, a US Colorado State University
assistant professor who led the research.
Global warming caused by human-made greenhouse gas emissions has
increased the average temperatures of Earth's near-surface air and
oceans since the mid-20th century.
Most climate scientists agree that a continuation of the current warming
temperatures will result is more extreme weather-related disasters such
as flood and drought, the melting of glaciers and the expansion of desert
and rangeland degradation.
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posted to ClimateConcern by eve of Earthcharter Foundation