Assessing the Effectiveness and Driving Forces of the Ecological Conservation Redline in Hainan Island Based on the Multiple Ecosystem Service Landscape Index

The Ecological Conservation Redline (ECR) is a key spatial policy tool in China’s efforts to protect the Ecosystem Services (ES) of Hainan Island. However, its effectiveness in promoting the coordinated restoration of Hainan Island’s ES remains unclear. This study employs the InVEST model to assess the spatiotemporal dynamics of carbon storage, habitat quality, water yield, and soil retention within the ECR zones of Hainan Island from 1990 to 2020. A Multiple Ecosystem Service Landscape Index (MESLI) was constructed, and Geographically Weighted Regression (GWR) was applied to examine the influence of ECR implementation on ES synergies and the spatial drivers underlying these patterns, aiming to elucidate the complex interactions between conservation policy and ecosystem functioning. The results show that (1) the delineation of the ECR has facilitated ecological restoration in the region. MESLI detrimentally declined before 2010 but positively increased by 12.7% during 2010–2020, indicating an improvement consistent with the period of ECR implementation. Moreover, (2) ESs within the ECR display marked spatial heterogeneity. GWR results reveal that MESLI is positively associated with vegetation cover and slope, and negatively associated with population density, with pronounced disparities in northern and central regions that call for differentiated governance strategies. Finally, (3) constructing a composite evaluation framework based on multiple ESs contributes to optimizing the delineation and management of ECRs, enhancing their scientific support for regional sustainable development. This study provides decision-making guidance for the zoned governance of conservation areas on tropical islands and offers insights for redline management in other ecologically sensitive regions.