Ecological vulnerability assessment of mangroves along coasts of China's mainland based on remote sensing and multi-criteria approach

With the expansion of human activities in coastal areas, China's mangrove ecosystems face increasingly severe environmental risks. Scientific assessment of their ecological vulnerability is essential for sustainable protection. This study constructs a comprehensive assessment model, combining game theory weighting method with two improved objective weighting models to quantify the impact of historical data from 2003 to 2023 on current vulnerability. The assessment system covers four criteria layers and 16 indicator layers, and multi-criteria decision analysis (MCDA) is used for weighted calculation. The results show that 77.76 % of mangrove areas have low vulnerability, while high-vulnerability areas are mainly concentrated in the Pearl River Delta, central Fujian and southern Zhejiang. Sensitivity analysis shows that the pressure of socio-economic activities has the most significant impact on vulnerability (mean sensitivity of 73.52 %), followed by marine industry (53.14 %) and pollution control (51.1 %), and the natural conditions of mangroves have the least impact (30.98 %). The study found that external pressure (such as economic activities and industrial development) is the main driving factor of mangrove vulnerability, while natural factors have a weaker effect. This study provides a scientific basis for the assessment of mangrove ecological vulnerability, supports government management and ecological protection policy formulation, and promotes the coordination of economic development and mangrove protection in coastal areas.