遥感与GIS支持下近十年中国草地变化空间格局分析

Spatial Pattern And Its Analysis of China's Grassland Change in Recent Ten Years Using Remote Sensing and GIS

以遥感与GIS为技术支撑 ,动态监测我国草地资源近十年的变化情况 ,为草地资源的可持续利用与管理提供科学依据。近十年来 ,我国的草地资源变化在空间上有明显的地域差异。表现为草地变耕地主要分布于我国的东北三省 ,与内蒙古的东部地区 ;草地变为城镇交通用地在很大程度上与区域的人口、经济发展有联系 ;草地变林地分布主要集中于沿海地区 ;草地退化集中于内蒙古、新疆、青海。草地变化虽然与自然条件有关 ,但人类活动对草地变化有很大影响。同时草地的退化对我国的生态环境 ,尤其是北方将产生不良的作用 ,在一定程度上制约区域经济发展。

Human interventions in natural systems have resulted in large change in vegetation composition and distribution pattern. The Land Use Change and Climate Change (LUCC) study under the International Geosphere Biosphere Program(IGBP) is a major initiative in this regard. Grassland change plays an important role in global change. This paper dynamically monitors status of grassland change in China from 1980s to 2000 based on RS & GIS. The data are extracted from LANDSAT TM image. From these data, the type of land use is decided on basis of the interactive MGE environment. To diminish the geometric error of the image, we adopt the processing method of Least-Square. As for pixel sampling method, we adopt the method of Nearest Neighbour Interpolation or Bilinear Interpolation. After the image processing, the maximum geometric errors are 2-3 pixels. The task of image classification is mainly taken by experts with the help of relief map, navigation photo etc, thus landuse coverage could be acquired. In the study, following conclusions can be drawn:(1)There is obviously zone difference of grassland dynamic change in China. From grassland being changed to farmland, mainly occurs in Heilongjiang province, Jilin province, Liaoning province and east Inner Mongolia. From the grassland being turned to urban, affects the relationship with regional population, economic development. From the grassland being changed to forest, mainly concentrates in southeast littoral; Grassland degradation is mainly distributed in Inner Mongolia, Xinjiang, and Qinghai. Grassland change bears on natural condition, but human activities have heavily impact on it. Grassland degradation has adverse impact on environment, especially north China and it will restrict regional economic development.(2)As for the grassland's change, there are many phenomena of farmlands occupy grasslands. The farmlands occupation of grasslands plays a leading role in the change. The occupation by farmlands is more serious in arid and semi-arid regions. The grassland's occupation by farmland at different levels for all coverage levels of grassland is mainly located in the non-monsoon zones.(3)The main reason of the grassland area decrease and coverage level reduction is that the resources' functions are continually greatly wrested under the push of human demand for economy and the dictate of benefit. This is also the contradiction between the development and ecologic administration which are faced by the west regions of our country.