Abstract: Understanding vegetation soil interaction in costal wetland is essential for coastal vegetation rehabilitation. In this study, we analyzed the response of Scirpus mariqueter to the spatial variation of coastal sedimentation and to establish the relationship between vegetation index and soil physicochemical parameters. We collected the data of soil physicochemical parameters and elevation of 32 soil samples in 2015 and 2017 and spectral reflectance of S. mariqueterin seven sampling locations with highdensity vegetation cover in the east tidal flat of Nanhui coastal area in Shanghai. The interaction between vegetation index and soil physicochemical properties and their response to tidal flat elevation were analyzed using correlation analysis, regression analysis, and spatial analysis by ArcGIS. Amplitude of elevation and NDVI variations was classified into 12 grades, with median 6 as the threshold for analysis. Results showed that the proportion of area with both NDVI and elevation variation amplitudes of no less than 6 was 51.45%. Most of these areas were located at the eastern part of the study site. 80.45% of area with NDVI variation amplitude of greater than 6 was included in the area with elevation variation amplitude of greater than 6. Moreover, both elevation and NDVI synchronously increased year by year after reclamation. Soil salinity and soil moisture were spatially correlated with tidal flat elevation, and both of them were the controlling factors for the spatial distribution of S. mariqueter. Our results suggested that the variation of tidal elevation caused by sedimentary environmental differentiation was the key factor controlling S. mariqueter spatial expansion. NDVIbased vegetation analysis could provide a holistic approach to understand the overall dynamics of vegetation change and dispersal.

Key words: oak, Pb/Zn mine tailing, phytostabilization