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..