中文摘要：

利用1980年、1995年、2000年三期遥感影像，在RS与GIS支持下，解译提取吉林省西部20年草地空间信息，分析该区草地时空动态及其景观格局变化。结果表明：①20年来，草地面积减少40．70％。草地退化严重，主要转化为耕地和盐碱地，转移面积分别达到475799．43hm^2和303182．06hm^2；②20年来．草地总动态度为负，1980～1995年，高覆盖度草地对整体草地变化影响较大；1995-2000年．高、中覆益度草地对草地整体变化影响较大；③20年来，各类草地质心向东北方向偏移。不同阶段各类草地质心偏移表现出无规律性、多向性；④总斑块数、平均斑块面积，平均斑块周长和优势度指数整体动态呈下降趋势，分维数变化较小且接近于1，各类草地破碎度指数整体动态呈增长趋势，破碎化程度加强，总体格局复杂化。自然因素对草地退化起到一定的驱动作用。人类活动干扰则是主要驱动力。

英文摘要：

By using three-period （1980,1995,2000） remote sensing images and with the support of RS and GIS, spatial information of grassland landscape in west Jilin province from 1980 to 2000 is extracted, spatio,temporal dynamics of grassland and change of grassland landscape patterns are analyzed. The results show：①From 1980 to 2000, 40.70% of grassland decreased ; and grassland seriously degraded. Grassland is mainly converted into cropland and saline-alkalized land, conversion area reaches 475 799.43 hm^2; and 303 182.06 hm^2 respectively ;②From 1980 to 2000, total dynamic degree of grassland is a minus value. During 1980-1995, high coverage grassland has a strong effect on change of whole grassland. During 1995; 2000, high and moderate coverage grasslands heavily affect change of whole grassland; ③In the last twenty years, the centroids of all kinds of grasslands moved towards northeast direction, and in different phases, the eentroids change of each kind of grassland are irregular and multi-directional; ④During 1980; 2000, on the whole, total number of patches, mean patch area, mean patch perimeter and dominance index have a decrease tendency, mean patch fraetal dimension little changes and its value is approximate 1, the whole dynamics of fragmentation indices of various grasslands has an increase trend, and fragmentation degree is more serious, the whole pattern becomes complication. As far as grassland degradation in the study area is concerned, natural factor takes some driving acting, but human actions are dominating driving power.