The Impacts of China’s Shan-Shui Initiative on Ecosystem Services: A Case Study in the Three Gorges Reservoir Area

This study investigates the impacts of China’s Shan-Shui Initiative on ecosystem services (ESs) in the Badong–Zigui–Yiling region of the Three Gorges Reservoir Area from 2015 to 2023, aiming to establish a methodological framework for evaluating large-scale ecological restoration programs and clarify the spatiotemporal dynamics, trade-offs/synergies, and driving mechanisms of ESs. Using the InVEST model, the coupling coordination degree model, and Geodetector, we assessed 4 key ESs: carbon sequestration (CS), soil conservation (SC), water yield (WY), and nitrogen retention (NR). Results show that the Shan-Shui Initiative substantially enhanced all 4 ESs, with CS increasing by 5.10 × 10 6 t, SC by 5.97 × 10 9 t, WY by 2.85 mm, and NR by 1.35 × 10 5 t during the study period. Synergies among ESs were strengthened (e.g., the CS–NR synergy rose from 0.665 to 0.681), while trade-offs weakened, which indicates the possibility of the multi-objective realization of the Shan-Shui Initiative. The coupling coordination degree of the 4 ESs improved from 0.285 to 0.298, indicating more collaborative development. Dominant driving factors varied by ES: forest and farmland proportions primarily influenced CS and NR; slope was key for SC; and elevation and gross domestic product jointly determined WY. These findings demonstrate the effectiveness of the Shan-Shui Initiative in improving ESs and provide a reference for optimizing ecological protection policies in similar regions globally.