Application of Ecological Theory to Management of Arid Drylands: An Example from China

Rangeland ecosystems shift across dynamic thresholds between different ecological states in response to natural or human-induced factors. These different ecological states are the result of interactions among climate, soils, grazing history, and management practices. The notion of a single ‘‘pristine’’ final state is only conceptual in nature, and because of this, dynamic thresholds and the effects of various processes on ecosystem structure and function must be incorporated into decision-making. Rangeland managers should have a working knowledge of the key ecological processes in each state, and the processes that drive a system across a dynamic threshold from one state to another. To do this they need indicators for critical decision-making points. It is essential to identify the thresholds of an ecological transition state and ecological indicators of these states. The criteria of these ecological indicators might be measurable, sensitive to stress on the system, have a known response to disturbance and easy to measure. The state and transition approach may offer an appropriate framework as an aid for decision making and can be used to highlight ‘‘management windows’’ where opportunities can be seized and hazards avoided. China’s vast drylands are used as a case study and the potential to apply these principles is discussed.