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土地利用以及由此引起的土地覆盖的变化是全球变化最显著的方面,也是影响草原生态系统质量的重要因素。文中以1987年、2000年和2005年三年的研究区TM遥感影像数据为基础,利用土地利用动态度模型和土地利用转移矩阵,分别从土地类型变化的速率和变化方向两个方面对锡林郭勒草原国家级自然保护区进行了研究。结果表明:(1)保护区的土地总体上明显退化,土地利用变化的总体趋势为草地和水域面积减少;耕地、沙地、沼泽地、居民点用地和裸岩、石砾地的面积增加,其中耕地、沙地和居民点用地的增加幅度比较大。(2)自2000年以后个别地方的土地退化现象得到了遏制,土地质量日益好转。(3)1987年至2000年的新增耕地全部来自优良的牧草地和湿地,2000年以来耕地的增长加快,开垦的范围也从原来的优良牧草地和湿地扩展到了低覆盖度草地和一些未利用土地。(4)高覆盖度草地退化和开垦严重,比例分别占减少面积的85.84%、11.51%。(5)18年间,研究区新增沙地20769.82hm2,主要来源于草地,草地沙化严重。
Land use and consequent changes in land cover are among the most significant aspects of global change and are also important factors affecting the quality of grassland ecosystems. Based on TM remote sensing image data of 1987, 2000 and 2005, using the dynamic model of land use and land use transfer matrix, this paper analyzes the effects of land type change rate and direction on Xilin Gol Grassland National Nature Reserve has been studied. The results showed that: (1) The land in the nature reserve degenerated obviously as a whole. The overall trend of land use change was that the area of grassland and water area decreased; the area of cultivated land, sandy land, swamp land, residential land and bare rock and gravel land increased, Among them, the increase of cultivated land, sand land and residential land is relatively large. (2) The land degradation in some places has been checked since 2000, and the land quality is getting better. (3) All new cultivated land from 1987 to 2000 came from fine forages and wetlands. Since 2000, the increase of arable land has been accelerated. The range of reclamation has also been extended from the fine pastures and wetlands to low-coverage grasslands and some Use of land. (4) High coverage The grassland degradation and reclamation were serious with the proportions accounting for 85.84% and 11.51% of the decreased area respectively. (5) During the 18 years, 20769.82hm2 of newly added sandy land in the study area was mainly derived from grassland and grassland was severely desertified.