Identifying Trends in the Distribution of Vegetation in Mongolia in the Decade after its Transition to a Market Economy

抄録

The spatial distribution of vegetation trends identified by time series analysis of the normalized difference vegetation index (NDVI) for the Mongolian grasslands was cross-referenced with the recently obtained land use/cover data and socioeconomic information in the geographic domain. Global Inventory Modeling and Mapping Studies (GIMMS) dataset with an 8-km resolution provided by the Global Land Cover Facility (GLCF) of the United States were used to compute the vegetation trends. We cross-referenced the vegetation trends obtained from the land use/cover information as of 2005 extracted from the European Space Agency′s (ESA) GlobCover land cover dataset and the Mongolian livestock statistics. We found that vegetation or pasture degradation prevailed in the decade after 1990. Results indicated that 21.1% of the vegetation degradation occurred in croplands, mainly in the northcentral part of the country, which may be linked to the abandonment of large-scale state-operated farmland after 1990 when Mongolia made the transition to a market economy. A decline in the vigor of vegetation was also commonly observed in provinces where livestock numbers surged, and may be attributable to the over-exploitation of pasture resources. However, a greening belt was observed around the mountain areas along 45°N. The number of livestock remained relatively constant and no major land use/cover change was observed in these areas, suggesting that the improved vegetation vigor was attributable to the recent global climate change.