中文摘要：

生态退耕使我国西北干旱与半干旱生态脆弱区土地结构和功能发生重大变化,对生态系统服务产生深刻影响。本文运用地理信息系统和遥感技术,分析了1990和2005年,盐池县土地利用和土地类型变化的规律;利用修正的中国陆地生态系统服务价值当量因子,计算出两期生态系统服务价值;分析了土地利用和土地类型变化对生态服务价值的影响。结论如下：1）1990-2005年间,研究区耕地、林地、草地面积得到大幅增加,未利用地大幅减少。2）研究区生态服务价值1990年为99064.6万元,2005年为115421.0万元,增加了20.62%。3）导致生态服务价值变化的主要原因是未利用地大幅度减少,相应转化为单位生态系统服务价值较高的林地、草地、耕地等。研究表明,生态退耕促进了区域土地类型结构优化和生态系统服务功能改善,但是将大量未利用地转化为农田和人工林地的长期生态效应还需进一步观察。文中研究对协调类似区域人地关系,改善人类生存环境和生活福祉具有指导价值。

英文摘要：

The ecological restoration program has significantly changed the land-use structure and function in arid and semi-arid regions of northwest China,posing profound impacts on regional ecosystem services.Taking the Yanchi county in Ningxia Autonomous Region as an example,and supported by GIS and remote sensing technologies,this study detected the changes of land use types during 1990 to 2005.Based on the modified equivalency factors of Chinese terrestrial ecosystem services,we further calculated how these kinds of changes influence the eco-services value.The results show that during 1990-2005,the areas of farmland,woodland and grassland increased significantly,while the unused land decreased dramatically.The eco-services value of Yanchi improved by 20.62% from 990.65 million Yuan in 1990 to 1154.21 million Yuan in 2005.The main reason of changes in ecosystem services values was due to a large percent of unused lands has been transformed into woodland,grassland,and farmland,which own higher per unit value of eco-services.Our findings indicated that the ecological restoration program can greatly facilitate the land-use structure optimization and ecosystem services improvement.This study can be a reference for coordinating regional human-nature relationships,and improving human environment and social welfares.