Analysis of the driving forces of vegetation dynamic changes in southwest China

Based on the Normalized Difference Vegetation Index (NDVI), land use and climate datasets, this study analyzed the trend of change in vegetation growth and clarified the impact of climate change and urban expansion on vegetation dynamics in southwest China by the ensemble empirical mode decomposition, partial correlation analysis and segmented linear regression. The results showed that the NDVI in the southwest China fluctuating increased, indicating an obvious vegetation greening trend; spatially, the regions with high NDVI were distribution in the southeast part and the regions with low NDVI were concentrated at the northwest part. Compared to the solar radiation and precipitation, the influencing scale and degree of temperature on regional vegetation growth was relatively large, accounting for approximately 64.6% of the study area, mainly distributed in the central and western parts of the study area. The land urbanization, economy urbanization and demographic urbanization increased over time, and the spatial distribution of these three urbanizations was relatively consistent. At the county scale, the correlation between economic urbanization, demographic urbanization and vegetation growth increased firstly and then decreased, showing a nonlinear characteristic; while there was a negative correlation between land urbanization and vegetation growth. At the grid scale, the relationship between these three urbanization and vegetation growth remains unchanged; but there were significant differences in the thresholds of nonlinear relationship and the slope of linear relationship. This study can provide scientific reference for implementing more precise ecological management measures and achieving sustainable socio-economic development in this region. © 2023 Chinese Society for Environmental Sciences. All rights reserved.