The 33 years (from 1981 to 2013) vegetation fractions were estimated based on NOAA/HAVRR NDVI and MODIS NDVI data in Xilingol steppe.Variations in grassland degradation were quantified according to the national standards of grassland degradation, the driver factors were analyzed as well.The results indicated that the grassland was in a degradation trend in studying period.However, the degradation states are different before and after the year of 2000.Before 2000 the degradation was in deterioration, but between 2000 and 2005 degradation changed.The grassland in the middle and eastern of Xilingol steppe improved, on the contrary the western was worse.After 2005 the whole area grassland was getting better, especially between 2010 and 2013.Degradation area was shrinking, and the degraded grassland was dominated by moderate and mild degraded grassland.The stocking number and grassland reclamation of farming activities and population quantity were the main factors of grassland degradation in Xilingol steppe.Summer precipitation and average temperature were other important factors to intensify grassland degradation.Meanwhile unreasonably mining of energy and mineral resources were other important factors to cause grassland degradation.%利用NOAA/HAVRR NDVI与MODIS NDVI遥感数据,估算得到锡林郭勒盟草原33年(1981~2013年)的植被覆盖度,根据草地退化国家标准,得到锡林郭勒草原草地退化的变化情况,并对其驱动因素进行研究.结果表明:在研究期内,研究区草地处于长期退化趋势,但2000年是草地退化的转折点.2000年之前,研究区草地呈退化加剧态势;2000~2005年草地退化发生转变,中、东部区域草地整体好转,西部地区草地恶化态势加剧;2005年之后,草地生态不断好转,尤其在2010~2013年,草地退化面积不断萎缩,退化草地中,以中度、轻度退化草地占主导.究其驱动因素,草地载畜量与草地开垦等农业经营活动及人口数量是主要因素;夏季降水量与夏季平均气温变化也是加剧草地退化的重要因素;能源矿产资源的不合理开采是导致草地退化的另一重要因素.
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