IDENTIFYING TRENDS IN LAND DEGRADATION IN NONEQUILIBRIUM RANGELANDS

1. Change in environmental conditions in the complex non-equilibrium r angelands of arid Australia is difficult to monitor. We show how trend s in rangeland condition can be identified from changes over time in t he pattern of vegetation growth across gradients of differing grazing intensity. 2. Grazing intensity was measured indirectly using distance from water. Vegetation growth was derived from remotely sensed vegeta tion index values before and after large rainfalls, The amount of grow th was adjusted for initial vegetation cover to give a standard measur e of vegetation response. 3. A vegetation response ratio was derived b y comparing areas less than 4 km from water with benchmark areas furth er away. Systematic changes in this ratio over time indicate a trend. 4. Ratio values from test areas suggested decline, improvement and no change, consistent with recent management history. 5. The method can b e applied where the whole area is affected by grazing and relatively p ristine benchmarks are unavailable. It could therefore be useful in th e semi-arid rangelands where paddocks are smaller than in the arid par t of Australia. It also has possible uses in the rangelands of Africa and the Americas. There is potential for applying the method to tradit ional grazing systems as well as to commercial pastoralism. 6. The met hod is cheaper and more effective than other techniques and increases the capacity of grazing gradient-based monitoring schemes for arid and semi-arid areas.