Spatially heterogeneous impacts on rangeland after social system change in Mongolia

After the social system in Mongolia changed from socialism to capitalism in the early 1990s, the cooperative system called negdel, which helped to disperse the grazing pressure, collapsed. As a consequence of the collapse, scientists warned that grazing pressure would become concentrated and fixed at particular locations, resulting in land degradation. However, no quantitative studies of such potential local concentration have been performed in Mongolia. In this study, using satellite images and large-scale thematic maps, we analysed the local vegetation change in relation to possible control factors, including open water, roads and settlements. Individual factors had significant impacts on the local vegetation change: particularly prominent were a beltlike decrease in plant density along the main roads and decreases around densely populated areas. In addition, the interaction between these factors negatively affected vegetation, as seen by a decrease around roads and open water near settlements. This interactive effect is likely a consequence of the basic requirements of the nomadic pastoralists, namely quality grassland, water sources and the services provided by settlements. In our study area in Mongolia, the local pattern of vegetation change was determined by the complex process of pastoralists' decision-making. A comprehensive understanding of this process is essential for devising management plans to counteract this vegetation degradation. Copyright (C) 2007 John Wiley & Sons, Ltd.