Impacts of exotic mangrove introduction on ecosystem health and service functions: A case study of three representative regions in Guangdong Province

Exotic mangrove species have been widely introduced in mangrove restoration projects across China due to their adaptability and high afforestation efficiency. However, their potential ecological invasion risks remain controversial, and systematic evaluations of their effects on ecosystem health and service functions are still lacking. This study investigated three representative mangrove ecosystems located in eastern Guangdong (Gaoshawei), western Guangdong (Shuidong), and the Pearl River Delta region (Yanzhou), based on field surveys conducted in 2024. A comprehensive evaluation of ecosystem health and ecosystem service values was conducted, incorporating key variables such as the proportion of exotic mangrove species, water quality, and biodiversity. Results showed that all three mangrove ecosystems were in sub-healthy condition, with per-unit-area ecosystem service values of 31.9×104CNY·hm-2 in Yanzhou, 27.5×104CNY·hm-2 in Shuidong, and 27.1×104CNY·hm-2 in Gaoshawei. The proportion of exotic species showed a significant negative correlation with both health index and ecosystem service value. A linear mixed-effects model revealed that for every 1% increase in exotic species proportion, the health index declined by 0.936, and the service value decreased by 1.456×104CNY·hm-2. These findings highlight the multidimensional impact of exotic mangrove introductions on ecosystem structure and function. This study proposes restoration strategies that emphasize native species, water quality improvement, and enhancement of ecological functions, providing scientific guidance for exotic mangrove management and functional restoration.