农牧交错带近十五年生态环境变化评价——以鄂尔多斯地区为例

Ecosystem change and assessment of ecotone between agriculture and animal husbandry regions in North China in the last fifteen years——A case study of Ordos Prefecture,Inner Mongolia

农牧交错带是我国生态最为脆弱的地区之一,生态系统极易受内外营力的影响产生扰动和变化,是我国生态状况变化最快最频繁的区域之一。该研究以Landsat的TM/ETM+、Spot的Vegetation数据为数据源,选取我国典型的农牧交错带鄂尔多斯地区为研究区域,根据两种数据的特点,对TM/ETM+影像以研究区域内土地退化、沙化为重点,对Vegetation以反映研究区域生物量变化的植被指数为指标,分析了近十五年来该地区生态环境的变化,并对研究区域近50年来的气候变化进行了研究。认为:该区域在研究时段的前段生态环境在持续退化,土地沙化和草地退化是这一时期的研究区域生态环境变化为主要特点,而后期生态环境出现了比较明显的恢复,时间转折点出现在2001年;气候变暖和降雨量的变化在这种变化过程中起了重要作用。其中,降水量的变化与生态环境的变化吻合良好。

The transitional zone between the agricultual and pastural areas is one of the most vulnerable regions in China, whose ecosystem tends to disturbance and change influenced by inner and outer factors. This paper adopted the TM/ETM ＋ and SPOT VEGETATION data as data sources and chose Ordos grassland as a research area. Ac- cording to the data characteristics TM/ETM ＋ images were used to analyze the land erosion and desertification, and VEGETION data were applied to acquire NDVI which is a biomass index. The paper analyzed the ecosystem dynamic change in the region in the recent 15 years. Based on the research, the paper reached the conclusions： （1） the ecosystem of this zone was in degeneration before 2001, land desertification and grassland degeneration were major features of ecosystem change in the period; however, the ecosystem got distinct restoration after 2001. The time when the ecology and environment in the region changed from degeneration to restoration was in 2001. （2） the wanning climate and the precipitation change were responsible for such ecosystem change. Among them, the precipitation change was considerably in accordance with the ecology and environment change.