摘要
本文以泾河流域为例,应用遥感与GIS方法,对该流域1986年、1995年和2000年3个时期的土地利用变化情况及其特点进行了分析。结果表明:①从1986年至2000年,泾河流域土地利用结构变化不大,均以草地和耕地为主,二者始终占流域总面积的85%以上;其次是林地,占流域总面积的10%左右,其他3种土地利用类型仅占流域总面积的5%左右;②土地利用变化总体来说,林地和草地呈现减少趋势,建设用地和耕地则呈增加趋势;未利用土地和水域面积变化不大;③从1986年至2000年这15年间不同土地利用类型间的相互转化比较复杂,主要发生在林地、草地和耕地三者之间,以草地—耕地转型为最大,达14·87×104hm2。值得注意的是,在草地的亚类间发生的变化,要远大于大类间的相互转化,转化面积均在53×104hm2以上,占草地总面积的1/6,这一变化过程虽然没影响到草地的面积,但却暗示了草地质量先退化后恢复的演变趋势;④政策、城镇扩张和人口增加是造成泾河流域土地利用变化的3个主要原因。
In the second half of the 20th century, rapid development of Northwest China caused many environmental problems, one of which is land use and land cover change. Many studies showed that land use and land cover change caused by people directly influenced form and evolvement of soil and water erosion. Based on Remote Sensing and GIS, this paper studies the land use change of Jinghe Watershed during 1986 to 2000, which locates in the northwest of Loess Plateau and is one of the areas that suffer most from soil and water erosion. The results are shown as follows: 1) in three periods, grassland and arable land are main types of land use, which occupied 85% of total area of Jinghe Watershed, area of forest is 10% and other three land use types only occupies 5% of total area, which showed land use structure changed little during 1986～2000. It also shows that at time scale within 20 years, the macrostructure of land use of a watershed doesn’t change greatly; 2) generally speaking, during 15 years between 1986 and 2000, the area of arable land, urban construction land have been increasing, which shows enlargement of cities and towns is the main reason. Results also show that the area of woodland and grassland decreased between 1986 and 1995, while increased between 1995 and 2000, which shows the implementation of policies has won initial success in some area of Jinghe Watershed in some sense; 3) During these periods, inter-transitions between different types of land use are very complex, mainly occurring among woodland, grassland and arable land. The most notable transition occurred between grassland to arable land, whose transferred area was up to 14.87×10~4 hectare. It is worthwhile to note that the transitions between subtypes of grassland are much bigger than the transitions between different types described above, and the transferred area were 53×10~4 hectare, which occupied 1/6 of total area of grassland, although these transitions didn’t change the area of grassland; it implied that the quality of grassland changed from degraded condition to recovery status; 4) The main reasons of land use change in Jinghe watershed are probably policies, the enlargement of cities and towns and the increase of population.
出处
《资源科学》
CSSCI
CSCD
北大核心
2005年第4期26-32,共7页
Resources Science
基金
国家973项目
农林复合景观的生态耦合关系及水土资源优化配置(编号:2002CB111506)。
