Abstract: Remote sensing, in conjunction with Geographical Information Systems (GIS) and Global Positioning Systems (GPS), has been used successfully in many studies on coastal resources, dynamical monitoring of the environment, and quantifying tidal flat vegetation. We investigated the potential of using multispectral satellite remote sensing to map and quantify an exotic plant, Spartina alterniflora, on tidal flats in Shanghai. A Landsat5-Thematic Mapper image, dated 2^nd August 2003, was geometrically corrected using ERDAS Imagine 8.6, and a sub-sample of the study area was then extracted. The sub-image was then analyzed using a Tassel Cap transformation (K-T) and the Normalized Difference Vegetation Index (NDVI) was used to identify different types of salt marsh vegetation. Based on these results, a series of classes were identified and a supervised classification was carried out using the Maximum Likelihood Classifier in ERDAS Imagine. The results of the classification were then checked using an in situ field survey of selected areas. The classification had an overall accuracy of 80%. The classified image was then integrated with other data in a GIS to analyze the spatial distribution of the S. alterniflora communities in Shanghai. The results showed that the total area of the S. alterniflora community in Shanghai was 4,553.37 hm² in 2003, which accounted for 22.1% of the total vegetation on tidal flats. Excepting Chongming Xitan and Hengsha Island, the S. al-terniflora community was distributed extensively on the tidal flats in the Changjiang Estuary. Nanhui Bian-tan accounted for 2,069.01 hm²; Chongming Dongtan, 910.17 hm² and Jiuduansha, 769.05 hm². The distribu-tion pattern of S. alterniflora showed that anthropogenic transplantation and the rapid proliferation of clones could be the main cause for successful expansion of this exotic. The results of this research indicate the po-tential of this approach for providing timely data for quantitative inventory of invasive plants over large ar-eas, and a scientific basis for biodiversity protection and sustainable utilization of tidal flats resources.

Key words: Nipponia nippon, habitat quality, geographical information system, conservation biology