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

Abstract

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