Thursday, 9 August 2012

New study: Grasslands doing fine even during severe droughts

Grasslands adapt well to droughts. That is the main message of a new study:

For much of the year drought has been plaguing American grasslands. But a recent study found that grasses do not appear to be losing the turf war against climate when it comes to surviving with little precipitation.

The Kansas State University-led study looked at the drought tolerance of 426 species of grass from around the world. The goal was to better understand how grasslands in different parts of the world may respond to the changes in frequency and severity of drought in the future.

Grasslands have several important ecological functions, according to Joseph Craine, research assistant professor of biology and the study's lead author. Grasslands convert and store carbon dioxide, are a food source for grazing animals like cattle and bison, and help cool the surrounding atmosphere. "The idea is that if you maintain a diverse grassland, you'll have a large number of drought-tolerant species ready to take over critical functions if there is a change in climate or an extended period of drought, like what we've had this year," Craine said. "Yet, we've never known which grasslands have drought-tolerant species in them." Craine conducted the study with Kansas State University's Troy Ocheltree, research assistant of biology; Jesse Nippert, assistant professor of biology; Gene Towne, biology research associate and Konza Prairie Biological Station fire chief; and Adam Skibbe, information resource specialist for the Division of Biology, as well as with colleagues from the University of Oregon and the Nature Conservancy in Minneapolis, Minn. It is the largest study conducted to quantify how tolerant grass species are to severe drought.

When comparing the drought resistance across the sampled species, the team found that drought-resistant grasses are well distributed across the world. As a result, grasslands are more likely to tolerate the increased periods and intensity of drought that are predicted with climate change in the future, Craine said. "If we still have grasslands that are diverse, the grasslands are going to continue to function relatively well and not change too much," Craine said. 

The benefits of a diverse grassland are evident when the U.S. faced a drought in the 1980s, said Towne, who also collects plant community data. "After that drought we saw a booming explosion of tall grasses the following year," Towne said. "So it really backs up what the study found: that drought forces the grasslands to adapt to the weather conditions so they can get through that rough period."


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