HESS Hydrology and Earth System Sciences HESS Hydrol. Earth Syst. Sci. 1607-7938 Copernicus Publications Göttingen, Germany 10.5194/hess-16-2585-2012 Dryland ecohydrology and climate change: critical issues and technical advances Wang L. 1 2 D'Odorico P. 3 Evans J. P. 4 Eldridge D. J. 5 McCabe M. F. 1 Caylor K. K. 6 King E. G. 7 Water Research Center, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia Department of Earth Sciences, Indiana University-Purdue University, Indianapolis (IUPUI), Indianapolis, Indiana 46202, USA Department of Environmental Sciences, University of Virginia, Charlottesville, VA 22904, USA Climate Change Research Centre, University of New South Wales, Sydney, NSW, 2052, Australia School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, 2052, Australia Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ, 08544, USA Odum School of Ecology and Warnell School of Forestry & Natural Resources, University of Georgia, Athens, GA, 30602, USA 09 08 2012 16 8 2585 2603 Copyright: © 2012 L. Wang et al. 2012 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://hess.copernicus.org/articles/16/2585/2012/hess-16-2585-2012.html The full text article is available as a PDF file from https://hess.copernicus.org/articles/16/2585/2012/hess-16-2585-2012.pdf

Drylands cover about 40% of the terrestrial land surface and account for approximately 40% of global net primary productivity. Water is fundamental to the biophysical processes that sustain ecosystem function and food production, particularly in drylands where a tight coupling exists between ecosystem productivity, surface energy balance, biogeochemical cycles, and water resource availability. Currently, drylands support at least 2 billion people and comprise both natural and managed ecosystems. In this synthesis, we identify some current critical issues in the understanding of dryland systems and discuss how arid and semiarid environments are responding to the changes in climate and land use. The issues range from societal aspects such as rapid population growth, the resulting food and water security, and development issues, to natural aspects such as ecohydrological consequences of bush encroachment and the causes of desertification. To improve current understanding and inform upon the needed research efforts to address these critical issues, we identify some recent technical advances in terms of monitoring dryland water dynamics, water budget and vegetation water use, with a focus on the use of stable isotopes and remote sensing. These technological advances provide new tools that assist in addressing critical issues in dryland ecohydrology under climate change.

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