Abstract
The definition of the concept 'rangelands' is discussed. Rangelands comprise about 50% of the Earth's land surface and support about 15% of its population. The need for monitoring of these areas to detect changes is stressed. The nature of vegetation change in rangelands, whether plant succession or state-and-transition, thresholds of environmental change, stability vs. resilience, equilibrium vs. non-equilibrium and the limitations of these concepts are debated. The concepts of range condition and trend are considered in relation to the effects of scale. Methods of range monitoring, including ground-based monitoring and remote sensing are described. It is concluded that it is unrealistic to expect a single coherent model or methodology to represent all rangeland situations, and that subjective as well as objective methods are important.