干旱区生态环境知识资源中心

Desertification has been widely treated as one of the major environmental hazards in the world by scientific communities and the public. In order to assess temporal-spatial variability of desertification from 1986 through 1993 to 2003 in an agro-pastoral transitional zone of northern Shaanxi, China, satellite images were interpreted and analyzed along with meteorological and socio-economic data. During the intervening 17-year period, desertification has decreased in severity and increased in extent. Temporally, severe desertification has decreased in area by 26.8% from 1986 to 2003. Desertification landscape patch quantities and fragmentation indexes have increased gradually. Spatially, desertification has increased in extent north of the Great Wall and decreased in extent in the Wudao river valley and north-western Shenmu County. The geographic centers of deserts in the study area have moved to the south-west and north-east. Climate change and human activities were somewhat responsible for the decrease in desertification severity but significantly affected the increase in desertification extent. The "Three north shelterbelt program" and "grain-for-green project" carried out by the governments were the dominant contributors to the desertification severity reversal. Desertification control is a difficult and gradually process and the government should continue to play a leading role in this process.