[Spatio-temporal Changes and Driving Factors of Vegetation in the Yellow River Basin]

The vegetation ecosystem in the Yellow River Basin is highly sensitive to climate change. Analyzing the driving mechanism of climate on vegetation dynamics plays an important role in the ecological management of the Yellow River Basin. Based on the data of the normalized difference vegetation index， total primary productivity， leaf area index， enhanced vegetation index， chlorophyll fluorescence， and vegetation coverage from 2001 to 2020， combined with the IGBP vegetation classification system， the differences and trends of vegetation characteristics of different vegetation types were quantified. By constructing a multi-scale geographically weighted regression model and Geodetector， the spatial heterogeneity and interaction mechanism of climatic factors and soil moisture on vegetation coverage were revealed. The results showed that： ① From 2001 to 2020， the vegetation in the central and eastern parts of the Yellow River Basin was significantly improved， whereas that in the northwest showed a trend of degradation， while the interannual variability of the middle reaches of the Loess Plateau was the largest. ② The vegetation characteristic index value of forest type was significantly higher than that of other types， and the vegetation coverage was the most sensitive to the differentiation of vegetation types. ③ In most areas of the Yellow River Basin， precipitation promoted vegetation growth， temperature inhibited vegetation growth in the north and middle， and saturated vapor pressure difference significantly promoted vegetation coverage in the southeast and northwest. In the humid areas of the south and southeast， the saturated vapor pressure difference showed a promoting effect， and the soil moisture showed an inhibitory effect. In the whole basin， precipitation and temperature， saturated vapor pressure difference， and soil moisture had a strong interaction， which promoted vegetation coverage. The research results provide theoretical support for the ecological zoning management of the Yellow River Basin.