The Land Use Change and Its Eco-environmental Effects in Transitional Agro-pastoral Region--A Case Study of Yulin City in Northern Shaanxi Province
北方农牧交错带土地利用变化及其生态环境效应--以陕北榆林市为例

Based on the data of land use/land cover of Yulin in northern Shaanxi, the process of land use change and its eco-environmental effects were quantified and analyzed, the results indicate: the land use pattern had a large change in the last 15 years. Farmland decreased by 405.98 hm2, and forestland and grassland increased by 17 157.02 hm2 and 107 975.17 hm2. The transitional quantities of no use land to grassland are the largest, and the following is degradation of grassland. The general quality of regional eco-environment has improved in the last 15 years. However, the trends of both improvement and degradation in eco-environment were coexist, and displayed their spatial heterogeneity in county-level. The land use change in Yulin has obvious regional difference, and in north wind-sand area the change is more serious and the process of land use change is more active. The spatial rule of eco-environmental effect caused by land use change presents: wind-sand area in north has a better improvement in eco-environment than that of hilly-donga in south. The main factors causing eco-environment change of improvement and degradation are transition of forest and grassland, and tree planting and forestation have the most distribution to the improvement of eco-environment, with its distribution ratio 74.8%.