Acid deposition and meteorological factors together drive changes in vegetation cover in acid rain areas

Vegetation, as a direct carrier of acid deposition, is often disturbed by climate change and environmental pollution, with multiple effects on its growth and distribution. However, the patterns of acid deposition and meteorological factors on vegetation growth in acid rain regions remain unclear. Therefore, we quantified the relative contributions of acid deposition and meteorological factors to develop a vegetation NDVI in Shaanxi, Chongqing, Fujian, and Guangdong Provinces during 2001–2021. Additionally, we employed RF and geographically and temporally weighted regression models. A RF model identified the main drivers affecting the NDVI, and the geographically and temporally weighted regression model further revealed the spatial and temporal heterogeneity of these factors. A geodetector was also applied to assess the combined effects of multifactor interactions of NDVI changes. It was found that temperature (TEMP), SO42−, NH4+, and precipitation (PREP) were the main drivers of vegetation cover changes in the acid rain area, with contributions of 16.06 %, 12.03 %, 10.37 % and 10.04 %, respectively, and the impacts on NDVI showed significant spatial–temporal heterogeneity. The negative effect of SO42− and the positive effect of NH4+ on vegetation growth varied with time and geographical location. effect on vegetation growth and the positive effect of NH4+ on vegetation growth showed complex dynamics depending on time and geographic location. More importantly, the interactions between SO42−, NH4+, temperature (TEMP) and precipitation (PREP) had a greater effect on NDVI than that of a single factor, suggesting that the factors did not act independently, but rather drove the changes of vegetation in the acid rain area together. This study illustrates the pattern of vegetation change in response to acid rain and confirms the interaction between acid deposition and meteorological factors influencing plant growth. Our results support the formulation of policy measures to mitigate the impact of acid rain on vegetation.