Spatial and Temporal Changes of Typical Vegetation in the Yellow River Delta Based on Zhuhai-1 Hyperspectral Data

The Yellow River Delta wetland boasts a diverse range of vegetation species and harbors an ecosystem that is both sensitive and fragile, so it is of great practical significance to accurately extract the vegetation information and analyze the spatial and temporal changes of this region. Based on the hyperspectral image data of Zhuhai-1, this study selected the characteristic bands through the continuum removal method. It combined these spectral attributes with index-based characteristics, utilizing the random forest algorithm to classify prevalent vegetation types while subjecting the outcomes to thorough analysis. It was shown that (1) when integrating spectral features, red edge indices, water indices, and vegetation indices to classify five distinct vegetation types in the Yellow River Delta during 2020 and 2022, the random forest classification algorithm showed higher classification accuracy, and the study achieved commendable overall classification accuracy rates and Kappa coefficients of 85.92% and 0.84, and 86.25% and 0.84, respectively. (2) In 2020 and 2022, the distribution of vegetation in the Yellow River Delta exhibited the following order: Suaeda glauca > Phragmites > Spartina alterniflora > Tamarisk > Typha orientalis Presl. With the exception of Spartina alterniflora, all categories of vegetation witnessed an increase in their distribution areas. Phragmites experienced the most significant growth, with an area expansion of 9.42%. (3) The ecological restoration and management measures taken in the Yellow River Delta have proven notably effective. The proportion of Spartina alterniflora within the vegetation decreased by 3.45%, the native vegetation showed a resurgence, the distribution pattern of vegetation communities moved toward stability, and the total area of vegetation in the study area exhibited an upward trajectory.