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ARS Home » Plains Area » Las Cruces, New Mexico » Range Management Research » Research » Publications at this Location » Publication #256307
Title: Cross-site studies "by design:" Experiments and observations that provide new insights

Author
item YAO, JIN - New Mexico State University
item SALA, OSVALDO - Brown University
item Peters, Debra

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 10/15/2011
Publication Date: 11/20/2013
Citation: Yao, J., Sala, O., Peters, D.C. 2013. Cross-site studies "by design": Experiments and observations that provide new insights. In: Peters, D.P.C., Laney, C.M., Lugo, A.E., et al., editors. Long-Term Trends in Ecological Systems: A Basis for Understanding Responses to Global Change. U.S. Department of Agriculture, Agricultural Research Service, Technical Bulletin Number 1931. p. 72-80.

Interpretive Summary: This chapter describes cross-site studies that are “by design” where the questions, experimental layout, methods, and measurements included multiple sites from the beginning. It presents examples of the kinds of questions and results that require a priori cross-site experiments or observations, and describes new insights provided by these studies that would not have been possible with cross-site comparisons conducted from existing studies. Two types of cross-site studies are described: (1) experimental manipulations of drivers or system properties, and (2) observations or monitoring of natural or managed ecosystems located along environmental gradients. Within each type, examples of both on-going or completed experiments and new or developing experiments are presented. The limitations and difficulties of this type of studies are listed.

Technical Abstract: The cross-site comparisons presented in the previous chapters are all conducted after the individual studies are completed. The differences in experimental design in individual studies in a posteriori cross-site studies limit the scope of questions that can be addressed, and the powerfulness and confidence in the conclusions. This chapter describes cross-site studies that are “by design” where the questions, experimental layout, methods, and measurements included multiple sites from the beginning. These a priori cross-site studies provide powerful tools to understand the phenomenon of global change and to predict its impacts on ecosystems and society. Two types of a priori cross-site studies are described: (1) experimental manipulations of drivers or system properties, and (2) observations or monitoring of natural or managed ecosystems located along environmental gradients. Within each type, examples of both on-going or completed experiments and new or developing experiments are presented. For each example, insights that would not have been obtained with other approaches are also presented. The limitations and difficulties of this type of studies are listed.