Significant Mediating Effect of Land Use Intensity: An Empirical Study on the Effects of Ecosystem Services Trade-Offs and Synergies in Jiangxi Province

Identifying ecosystem service (ES) trade-offs and synergies (ESTSs) and their effects provides a critical scientific basis for ecological management. However, the effects of ESTSs are not always direct. To compensate for the limited research on the multidimensional heterogeneity and mediating effects of ESTSs, Jiangxi Province was used as a case study for the analysis of spatiotemporal patterns and heterogeneity in ESTSs. Data from 1990–2020 were assessed from static and dynamic perspectives and from multiple dimensions. The direct and indirect effects of the normalized difference vegetation index (NDVI) and land use intensity (LUI) on ESTSs were also identified. We found that ESTSs were characterized by short-term fluctuations, dynamic changes, and long-term stability. Overall, ESTSs were stronger according to a static perspective than to a dynamic perspective and ESTSs were stronger at a small scale than at a large scale. Spatial heterogeneity in the relationships between and the degrees of ESTSs occurred across different multidimensional zones. The effects of the NDVI on ESTSs were significant, and the heterogeneity of these effects was significant across different dimensions. The influence coefficients were ranked as follows: functional control dimension > horizontal development circle dimension > vertical topographic position dimension. LUI can function as a vital mediator in the influence chain connecting the NDVI and ESTSs and manifests as a significant partial mediating effect. The goal of this study was to explore the empirical application of econometric statistical methods to the impact of ESTSs, thereby providing a foundation for targeted and differentiated ecological management policies and a reference for the governance of ESs in similar regions.