A Study On The Spectral Characteristics Of Salt Marsh Vegetation In Yangtze Estuary

The enormous quantities of sediment produced by the Yangtze River have created extensive areas of shoals and tidal flats in the estuarine region, which have been colonized by various types of salt marsh vegetation. By their very nature, salt marshes and inter-tidal zones are dynamic and their biodiversity conservation and management relies on up to date spatial information, i.e. there is an urgent need for using remote sensing to map the salt marsh at a large spatial extent. Remote sensing technology has become the primary tool for ecological research at large scales. The remote sensing images have different tone, shape, and texture features reflected by variant vegetation composition, and the relationship between vegetation and its spectral characteristics is essential in the interpretation of remote sensing images. However, there is a major problem in differentiating between different spectra for the same vegetation type and the similar spectra for different vegetation type, such as between the salt marsh plant communities dominated by the native species Phragmites australis and the exotic species Spartina alterniflora, as well as between the plant communities of Scirpus mariqueter or Scirpus triqueter and Carex scabrifolia, which have a similar canopy physiognomy, resulting in misinterpretation and misclassification of remote sensing images. A number of researchers have indicated that using greater spectral resolution in the form of hyperspectral data and using multi-seasonal spectral data may produce better results.The aim of this research was to investigate the spectral characteristics of salt marsh plant communities with a view of determining the utility of remotely sensed data, particularly the hyperspectral and high spatial remote sensing system (i.e. airborne et al.); to find and analyze the differences in spectral characteristics of salt marsh communities among different seasons; and to get a realistic strategy for classifying salt marsh vegetation using current operational satellite systems.Four major plant communities of salt marsh vegetation in Shanghai, i.e. Phragmites australis community, Spartina alterniflora community, Scirpus mariqueter community and Carex scabrifolia community were selected at...