中文摘要：

运用土地利用变化强度、土地利用程度变化率、生态系统服务价值以及GIS软件对榆林市土地利用时空格局演变及其生态响应进行了分析。结果表明，1990-2005年榆林市土地利用类型转换较快，耕地、林地、园地、城镇用地的土地利用变化强度分别达-0．46％，0．39％，0．09％，0．03％。1990-2005年榆林市生态系统服务价值呈现逐年增长态势，16年间增加了19．26亿元，同期耕地生态价值减少了8．19亿元，林地、草地生态价值分别增加了27．25和0．27亿元。县域生态系统服务价值结果显示，16年间靖边县生态系统服务价值下降了0．27亿元，其他各县均呈现增长态势。

英文摘要：

The paper selects the methods in landuse change and ecosystem evaluation. The result shows that the landscape type has transformed quickly in Yulin City from 1990 to 2005. The intensity of landuse change of cul- tivated land, woodland, orchard land, and urban construction land has reached -0.46%, 0.39%, 0.09%, and 0.03% respectively. Total value of ecosystem services has increased 19.26 × 10^8 yuan in Yulin City from 1990 to 2005. Meanwhile, the ESV of woodland and grass land has increased 27.25 ×10^8 yuan and 0.27 × 10^8 yuan respectively. On the contrary, the ESV of cultivated land has reduced 8.19 ×10^8 yuan during the 16 years.