Extraction and correlation analysis of growth parameters of Spartina alterniflora based on UAV remote sensing

With some areas of Yancheng coastal wetland as the study area, the canopy height, vegetation index, coverage and lodging rate of Spartina alterniflora were extracted by UAV multi-spectral lidar fusion technology in different phenological periods. The temporal and spatial variation characteristics of canopy height and vegetation index were analyzed, and the correlation coefficients between canopy height and vegetation index and other parameters were calculated. Three regression models were constructed. The results show that: (1) The canopy height of Spartina alterniflora gradually increased from withering stage to mature stage, and the canopy height gradually decreased as a whole from sea to land. The NDVI gradually increased from the wilting period to the flowering period, while the NDVI decreased in mature stage, and the NDVI gradually decreased from sea to land. (2) The canopy height was significantly correlated with vegetation index, coverage, lodging rate and spatial position in non-withering period. (3) There was spatial heterogeneity in the distribution of canopy height and vegetation index of Spartina alterniflora, and GWR was superior to OLS in model accuracy and spatial heterogeneity analysis.