Elevated CO2 Suppresses Dominant Plant Species in a Mixed-Grass Prairie
Climate controls vegetation distribution across the globe, with some vegetation types being more vulnerable to climate change and others more resistant. Because resistance and resilience can influence ecosystem stability and determine how communities and ecosystems respond to climate change, it is important to evaluate the potential for resistance in future ecosystem function. In a mixed-grass prairie in the northern Great Plains, researchers utilized a large field experiment to test the effects of elevated CO2, warming, and summer irrigation on plant community structure and productivity. This study sought to understand changes to both stability in plant community composition and biomass production. The researchers found that the independent effects of CO2 and warming on community composition and productivity depend on interannual variation in precipitation and that the effects of elevated CO2 are not limited to water saving because they differ from those of irrigation. They also show that production in this mixed-grass prairie ecosystem is not only relatively resistant to interannual variation in precipitation, but also rendered more stable under elevated CO2 conditions. This increase in production stability is the result of altered community dominance patterns: Community evenness increases as dominant species decrease in biomass under elevated CO2. In many grasslands that serve as rangelands, the economic value of the ecosystem is largely dependent on plant community composition and the relative abundance of key forage species. These results have implications for how native grasslands are managed in the face of changing climate.
Zelikova, T. J., D. M. Blumenthal, D. G. Williams, L. Souza, D. R. LeCain, J. Morgan, and E. Pendall. 2014. “Long-Term Exposure to Elevated CO2 Enhances Plant Community Stability by Suppressing Dominant Plant Species in a Mixed-Grass Prairie,” Proceedings of the National Academy of Sciences (USA) 111(43), 15,456-461. DOI: 10.1073/pnas.1414659111.