基于遥感的九段沙湿地植被群落动态变化分析

九段沙是长江口重要的新生湿地.作为主要地物类型之一的植被群落,是反映潮滩湿地生态环境变化重要而又敏感的指标因子.本文通过1987～2008年六景Landsat卫星遥感数据对九段沙植被群落进行了分类提取,并利用ArcGIS软件分析了长江口九段沙植被群落20年来的时空动态变化.结果显示1987～1997年间,九段沙湿地植被以先锋植被海三棱藨草为主,植被面积随潮滩不断淤涨而增长;1997年人工促淤种植了芦苇和互花米草,至2008年,芦苇、互花米草和海三棱藨草三种植被群落所占植被总面积百分比分别为31.47%、39.35%和29.17%,其中外来物种互花米草优势明显,当地植被海三棱藨草所占面积比例显著下降.

The dynamic changes analysis of the vegetation community in Jiuduansha tidal flat by using remote sensing

Jiuduansha is an important new tidal fiat in the Yangtze River Estuary.As one of main typical canopies over Jiudnansha tidal flat,vegetation is an important indicator factor which can show the variety of ecological environment.Based on the Landsat satellite remaote sensing data from 1987 to 2008,the authors analyze the spatial and temporal dynamic variations of vegetation communities in Jiuduansha tidal flat by using ArcGIS.The results indicate that Jiuduansha vegetation is in the natural succession stage and Scirpus mariqueter is the primary vegetation during 1980s-1990s.As the tidal fiat increases,the vegetations grow up quickly.Since 1997,Phragmites australis and Spartina alterniflora have been artificially planted.The percentage of Phragmites australis,Spartina alterniflora,Scirpus mariqueter was 39.35%,31.47%,29.17% respectively in 2008.The alien species Spartina alterniflora becomes the dominant species and the planted area for Scirpus mariqueter is decreased..