ARS | Publication request: Effects of seasonal drought on net carbon dioxide exchange from a woody-plant-encroached semiarid grassland
Research Project: HYDROLOGIC PROCESSES, SCALE, CLIMATE VARIABILITY, AND WATER RESOURCES FOR SEMIARID WATERSHED MANAGEMENT
Location: Southwest Watershed Research
Title: Effects of seasonal drought on net carbon dioxide exchange from a woody-plant-encroached semiarid grassland
Authors
Scott, Russell
Jenerette, G. - UNIV. OF CALIF. RIVERSIDE
Potts, D. - BUFFALO STATE COLLEGE
Huxman, T. - UNIVERSITY OF ARIZONA
Submitted to: Journal of Geophysical Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 28, 2009
Publication Date: November 4, 2009
Citation: Scott, R.L., Jenerette, G., Potts, D., Huxman, T. 2009. Effects of seasonal drought on net carbon dioxide exchange. JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 114: 1-13. G04004.
Interpretive Summary: The increase in the amount of woody plants (shrubs and trees) into grassland ecosystems is one of the most pervasive changes in land cover in the southwestern US and around the world. It is important to understand how this change in vegetation will affect water and nutrient cycling of ecosystems in order to predict the outcomes of this change on society. We measured energy, water and carbon dioxide exchange between a woody-plant-encroached grassland and the atmosphere over a four-year period and determined how the amount of precipitation controlled these exchanges. In contrast to the current paradigm that woody plant encroachment might result in more ecosystem carbon sequestration and to the many recent results showing that various semiarid ecosystems were a sink for carbon dioxide, we found
that this ecosystem was a source, which was likely a consequence of the decade-long drought that was on-going over the study period. These results highlight a complex relationship between vegetation change and climatic variation in precipitation that likely influences the carbon sequestration potential of water-limited landscapes.