Learning from episodes of degradation and recovery in variable Australian rangelands

*Commonwealth Scientific and Industrial Research Organisation Sustainable Ecosystems, Canberra ACT 2601, Australia;
^‡Department of Natural Resources and Water, Queensland Climate Change Center of Excellence, 80 Meiers Road, Indooroopilly QLD 4068, Australia; and
^§Department of Agriculture and Food Western Australia, Center for Management of Arid Environments, Curtin University of Technology, Northam WA 6401, Australia

Edited by B. L. Turner II, Clark University, Worcester, MA, and approved August 20, 2007 (received for review May 23, 2007)

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Fig. 1.
Schematic of the interactions between the human and environmental components of the land system (combining concepts from figure 21.5 in ref. 5 and figure 4 in ref. 3, with specifics for this analysis in italics), showing decision making and ecosystem services as the key linkages between the components (moderated by an effective system of local and scientific knowledge), and indicating how the rates of change and the way these linkages operate must be kept broadly in balance for functional coevolution of the components.
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Fig. 2.
Map of Australian rangelands, locating and briefly describing the degradation episodes analyzed in this article (episode 5 is omitted; see Materials and Methods). Shading indicates pastoral areas (sheep or cattle), forward hatching indicates episode regions with longer droughts, and back hatching indicates shorter droughts (diamonds indicate New South Wales had one of each).
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Fig. 3.
Time course of various features of the drought episodes plotted annually relative to start year of drought for each episode. (a) Rainfall (% of mean annual rainfall in base period). (b) Simulated pasture growth (percentage of mean pasture growth in base period). (c) Reported stock numbers (percentage of mean number in base period). (d) Grazing pressure (the ratio between the stock numbers and pasture growth, reported as percentage, a value of 100% implies the same balance between stocking and pasture growth as in each episode's baseline period; greater values indicate more stock than pasture growth). Each graph shows the mean of episodes 2, 4, 7, and 8 with short drought periods (■) and episodes 1, 3, and 6 with long drought periods (▲). (Adapted from figures 2.9 and 2.10 in ref. 1.)