Plants use carbon dioxide to create energy through a process called photosynthesis. But a new study finds that increased amounts of the gas aren't necessarily beneficial for grasslands in Wyoming.
David Williams, a botany professor at the University of Wyoming, and his team studied grasslands under warmer than usual temperatures and in environments with extra carbon dioxide.
The researchers surrounded plots of grass with heaters and pumped carbon dioxide into the air above them in order to simulate the atmosphere expected at the end of this century. They did this over two years, one of which was wet and the other was dry.
"There might be some species that are capable of existing within the system of change but other species that are not," he said. "In terms of just conserving biodiversity, it's important to understand the potential responses of these changes, changes in climate and changes in CO2 conditions, and how the grasslands respond."
The most common plant, western wheatgrass, didn't photosynthesize any more than usual. Its population actually declined. But Williams said other grasses performed better than they would normally.
"The responses to these changing conditions are very species-specific," he said. "Some species respond very favorably, others don't respond as much or at all to this increase in carbon dioxide."
In the wet year, the scientists saw more pronounced changes than in the dry year. Williams said changes in plant populations can affect grass's nutritional value, which is important for ranching and grazing.
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