南京市九乡河流域土地利用程度空间异质性分析

Spatial Heterogeneity of Land Use Degree in Jiuxiang River Watershed,Nanjing City,China

定量分析九乡河流域土地利用程度及其空间异质性,对确定该流域土地资源利用和保护方向、实现土地资源可持续利用具有重要意义。以2003和2009年2期遥感影像为基本信息,利用空间自相关以及半变异函数分析方法,探讨了2003-2009年九乡河流域土地利用程度的空间异质性特征,结果表明:流域土地利用程度的空间自相关表现出较强的正相关性,且与尺度密切相关,随着尺度的增大,空间自相关性逐渐下降;流域西北部的仙林大学城,以及北部的石埠桥一带土地利用程度的较高,南部的青龙山,中部的灵山及北部的西湖公园一带土地利用程度较低。从2003-2009年,九乡河流域的土地利用程度以较强土地利用程度为主,占流域面积的40%左右;受城市化过程的影响,流域土地利用程度的空间异质性发生了较明显的变化,流域土地利用程度呈现出向强和弱两极转化的趋势,6年间分布面积分别增加1.13%、4.27%;其中,仙林大学城一带的土地利用程度增强,且分布范围快速扩张,而九乡河源头、下游的沿岸及西湖公园一带的土地利用程度有所降低。

We quantitatively analyzed the space heterogeneity of land use degree in the Jiuxiang River wa- tershed. This is of great significance to land consolidation and sustainable use of land resources in the ur- banized watershed. Jiuxiang River watershed in Nanjing City, as a case study area, its two landscape clas- sification maps were conducted from 2003 and 2009 by remote sensing images interpretation, which were used as the main data source for assessment o{ land use degree. Spatial heterogeneity characteristics of land use degree in the study area were analyzed during 2003 - 009 by means of spatial statistics like spatial autocorrelation and semi-variance analysis. The results showed that with the increase of spatial distance, the spatial correlation of land use degree showed a downward trend in Jiuxiang River basin. The high val- ue area of land use degree was mainly located in the northwest Xianlin College Town and Shibu Bridge are- a, and the low value area mainly gathered in the northern Qinglongshan Mountain, the central Linshan Mountain and the northern West Lake Park area. Land use degree was mainly at the level of moderate in Jiuxiang River Basin from 2003 to 2009, accounting for about 40% of the watershed area. Affected by the urbanization process, the spatial heterogeneity of land use degree changed obviously, and the watershed land use degree showed the trend of conversion to stronger and weaker, the distribution area had an in- crease of 1.13% and 4. 27%, respectively in six years. The land use degree in Xianlin College Town area enhanced, showed a trend of rapid expansion, but the land use degree slightly decreased in Jiuxiang River headwater, along the downstream coast and the West Lake Park. So we should establish a watershed eco- logical planning or land use planning to reduce the land use degree by controlling the density of building lands strictly, protecting forestlands, and enhancing the landscape construction.