Responses of grassland production to single and multiple global environmental changes

• Published in: PLoS biology Vol. 3; no. 10; p. e319
• Main Authors: Dukes, Jeffrey S, Chiariello, Nona R, Cleland, Elsa E, Moore, Lisa A, Shaw, M Rebecca, Thayer, Susan, Tobeck, Todd, Mooney, Harold A, Field, Christopher B
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 01-10-2005; Public Library of Science (PLoS)
• Subjects: Atmosphere; BASIC BIOLOGICAL SCIENCES; Biochemistry & molecular biology; Biomass; Carbon dioxide; Carbon Dioxide - pharmacology; Climate; Ecology; Ecosystems; Environment; ENVIRONMENTAL SCIENCES; Experiments; Grasslands; Greenhouse Effect; Life sciences & biomedicine - other topics; Meteorological Concepts; Nitrates; Nitrates - pharmacology; Plant Roots - growth & development; Plant Shoots - growth & development; Plants; Poaceae - drug effects; Poaceae - growth & development; Precipitation; Rain; Seasons; Shoot growth; Studies; Temperature; Values; California; USA, California; Climate; Plant Shoots; Plant Roots; Greenhouse Effect; Environment; Poaceae; Nitrates; Meteorological Concepts; Carbon Dioxide
• ISSN: 1545-7885; 1544-9173; 1545-7885
• DOI: 10.1371/journal.pbio.0030319

In this century, increasing concentrations of carbon dioxide (CO2) and other greenhouse gases in the Earth's atmosphere are expected to cause warmer surface temperatures and changes in precipitation patterns. At the same time, reactive nitrogen is entering natural systems at unprecedented rates. These global environmental changes have consequences for the functioning of natural ecosystems, and responses of these systems may feed back to affect climate and atmospheric composition. Here, we report plant growth responses of an ecosystem exposed to factorial combinations of four expected global environmental changes. We exposed California grassland to elevated CO2, temperature, precipitation, and nitrogen deposition for five years. Root and shoot production did not respond to elevated CO2 or modest warming. Supplemental precipitation led to increases in shoot production and offsetting decreases in root production. Supplemental nitrate deposition increased total production by an average of 26%, primarily by stimulating shoot growth. Interactions among the main treatments were rare. Together, these results suggest that production in this grassland will respond minimally to changes in CO2 and winter precipitation, and to small amounts of warming. Increased nitrate deposition would have stronger effects on the grassland. Aside from this nitrate response, expectations that a changing atmosphere and climate would promote carbon storage by increasing plant growth appear unlikely to be realized in this system.