Some grassland ecosystems in Europe may be resistant to global warming

Washington, July 8 : New results from a long-term experiment indicate that grassland ecosystems found in higher altitudes throughout Western Europe may be resistant to climate change.

According to a report in National Geographic News, the finding is in sharp contrast to similar research conducted in an alpine meadow in North America that suggests mountain wildflowers will all but disappear in a warming world. Other studies have also shown major climate-spurred changes to plant composition in Minnesota bogs, Alaskan forests, and Siberian tundra.

But the new study found very little change in a European grassland even after 13 years of controlled exposure to higher temperatures and shifting rainfall patterns.

"It's taken a long time to recognize that some systems may be rather more resistant (to climate change) than those that were reported on earlier," said lead study author Philip Grime, an ecologist and emeritus professor at the University of Sheffield in England.

Between 1994 and 2006, Grime's team monitored 97-square-foot (9-square-meter) plots in a grassland in Buxton, England, normally used for grazing livestock.

Each plot was trimmed to simulate continued grazing but was kept 5.4 degrees Fahrenheit (3 degrees Celsius) warmer than nearby outside temperatures.

The team also manipulated rainfall patterns to mimic the droughts and deluges anticipated in a warming world.

Initially, the scientists saw an increase in some shrubs and a decrease in flowering plants such as rockroses and wild thyme due to the simulated droughts.

Otherwise, not much has happened to species composition at their research sites.

According to Grime and colleagues, one of the reasons for the grassland's resilience is that many of the species are long-lived. Some have leaves, for example, that have adapted to the vagaries of shifting weather. "They have a capacity over a very short time to adjust the internal physiology of their cells," Grime explained. This helps them to resist frost in the winter and drought in the summer.

In addition, recent research has shown that many of the plant species are genetically diverse at the local scale. So even if a spike in temperatures one year kills some individual plants, the survivors will be robust enough to repopulate the area.

"What's more, the limestone soil underneath the grassland is patchy. Soils are deep in some places, shallow in others; some drain well after heavy rains, others do not," according to Grime.

This combination of factors should keep the grasslands intact for years to come even in the face of global warming, his team said.

"Each plant will have winners and losers, but the net effect will be that the individual species-most of them-tend to survive," said Grime.

ANI