【摘要】 利用TM影像、遥感与GIS技术对我国不同干燥度草地资源动态变化研究结果表明,不同干燥度区域高覆盖度草地演替成耕地,其中以4、5、6级干燥度带为重,主要分布于我国西部和北部地区,各干燥度带下城镇用地均有占用草地现象发生,且有草地退化。中覆盖度下耕地占草地,与草地间互换基本相等,但耕地的占用表明草地减少,且有大量草地转变成林地。低覆盖度下随干燥度增加,草地沙化严重,尤其是4、5级干燥度带表现严重,对生态环境不利。但在1级干燥度带以草地变林地为主,其他几个干燥度带草地变林地、耕地均有发生,面积基本一致。草地退化主要是因过度放牧、盲目开垦耕地所致,而草地退化将导致我国北方环境恶化及资源退化。更多还原

【Abstract】 This paper studies the dynamic of the Chinese grassland resource in different aridity areas supported by GIS and RS based on TM images. The results show thai there is an obvious zone under different aridities where the high cover grassland is changed 10 farm land especially at 4, 5 . 6 degrees which are mainly distributed in the west and north of China and in these zone the grassland is being replaced by urban at each aridity area and the grassland is being degradated. The area between the grassland changing into farmland and farmland changing into grassland is about the same in middle cover grassland, but the area occupied by the farmland shows that the grassland decreases and a lot of grassland arc changed into forest. With the increasing aridity degree, the degradation becomes serious in low cover grassland, especially at 4, 5 degrees. But at 1 degree, the main change is that the grassland is changed to forest. The main reasons of grassland changing into farmland are the population pressure and over graze, etc. Grassland degradation will lead to the environment of north China worsen.更多还原