南四湖湿地补水前后景观格局变化分析

以2000、2002、2004、2009年4个时期的TM影像为主要数据源,结合其他辅助资料,利用ArcGIS及其扩展模块patch analyst、ERDAS 9.2提取了4个时期的湿地景观格局及变化信息,选取斑块数(NumP)、平均斑块面积(MedPS)、平均形状指数(MSI)、周长面积比(MPAR)、平均斑块分形维数(MPFD)、面积加权平均斑块分形维数(AWMPFD)等景观格局指数分析南四湖湿地补水前后景观格局的变化特点及原因。研究表明:补水前,南四湖湿地景观破碎,湖水域及裸露滩地面积所占比例比较大,补水后,景观格局得到明显改善。南四湖湿地景观格局变化的驱动因素主要有人为活动的影响和国家补水工程的实施。

Landscape pattern changes for Nansihu wetland before and after water supplement

By using TM images in 2000,2002,2004,2009 as the main data source,in combination with other information and the support of ArcGIS and patch analyst,ERDAS 9.2,we extract information for four periods about wetland landscape pattern changes and select the patch number（NumP）,mean plaque area（MedPS）,mean shape index（MSI）,perimeter area ratio（MPAR）,mean patch fractal dimension（MPFD）,area-weighted mean patch fractal dimension number（AWMPFD）and other landscape pattern indexes to analyze the changes and reasons of Nansihu wetland landscape pattern before and after water supplement.The results show that：Nansihu wetland landscape is fragile,the water area and the proportion of exposed beach area are relatively large before but significantly improved after water supplement.The driving factors of Nansihu wetland landscape pattern changes are mainly activities effects and the implementation of national water projects.