南京市绿地结构变化的遥感监测及驱动力分析

城市绿地景观是城市自然生态系统的主要组成部分.其数量、结构与城市发展和生态环境质量有着极其重要的关系.通过对南京市1988年、2000年和2002年3个时段的Landsat/TM遥感影像加工处理,将绿地景观分为生态绿化用地和农业用地,并通过景观指数的方法对其在15年间的景观格局和动态进行分析.结果表明:1988-2000年,南京市绿地景观总面积增加9.60%,斑块数减少,平均斑块面积增加,斑块形状趋向简单.聚集程度增加,总体破碎程度下降.而不同绿地景观类型变化不同:农业用地面积增加12.80%,在城区外围大规模聚集分布,破碎程度较低;生态绿化用地面积减少3.60%,小面积斑块数量大幅减少,景观形状变得更加规则,主要生态绿化用地斑块形成"孤岛"分布,破碎度呈下降趋势,景观异质性和多样性下降,绿地生态质量下降.与2000年比较,2002年城市生态绿地面积减少0.63%,农业用地减少14.60%,生态绿地景观趋向于面积较大的斑块数量减少和景观破碎化程度增加.城市绿地景观格局变化的主要原因是南京市城市化进程的加快以及城市所处自然环境变化的影响.

Analysis on Changes and Controlling Factors of Urban Green Spaces Based on Remote Sensing in Nanjing

Urban green space is an important part of the urban ecosystem, and its quantity and landscape pattern is tightly related to urban development. This research analyzed three Landsat/TM images of Nanjing in 1988, 2000 and 2002. The urban vegetation was divided into forest type and agricultural type, and the temporal-spatial changes of landscape pattern during the 15 years were studied by the landscape index. The results showed that the quantity of urban green space in Nanjing increased by 9.60%, with the number of patches decreasing, average area increasing, landscape shape being simplified, landscape aggregating and fragmentation being declined between 1988 and 2000. However, the results were different be- tween the forest type and agricultural type. the area of agriculture type increased by 12.80%, and expanded increasingly outside the city zone andshowed a low fragmentation; the area of forest type decreased by 3.60%, while the patches with little area reduced greatly, the landscape shape became more simple, the large forest patches were distributed more isolated, and the fragmentation also reduced. However, between 2000 and 2002,the area of forest type and argicultural type reduced by 0.63% and 14.60%. The large area of patches disappeared. The most important reason for the changes was the intense process of urbanization,and the natural conditions as well.