How Might Climate Change Affect Native Grasslands? Ten miles west of Cheyenne, carbon-dioxide levels are nearly twice as high as they are in the city. Well, at least in some test plots at the High Plains Grasslands Research Station. Thirty plots of native grasslands are part of an experiment to determine how local prairies could react to climate change. The results could shape congressional policy decisions, as well as rangeland management in the Rocky Mountain region. Wyoming's semi-arid landscape also is a good place to start, since grasslands cover more than 40 percent of the Earth's surface. "What makes it tricky is that weather and climate, by nature, are variable," said project leader and plant physiologist Dr. Jack Morgan from the U.S. Department of Agriculture. "You look out at this field, and there are probably 100 different plant species. To predict which ones will be the winners and losers is difficult." Experts know that the environment changes when a rancher puts cattle out to graze. What they don't know is how climate change will impact the animals' preferred meals or the invasive weeds that share the same space. Wyoming and southern New Mexico share similar precipitation levels, but dissimilar temperatures shape the scenery within each state....