Abstract: Exotic mangrove species have been widely introduced in mangrove restoration projects across China due to their fast growth and high afforestation efficiency. However, their potential ecological invasion risks remain controversial, and systematic assessments of how their introduction affects ecosystem health and service functions are still limited. This study investigated three representative mangrove areas located in eastern Guangdong, western Guangdong, and the Pearl River Delta regions, based on field surveys conducted in 2024. We comprehensively evaluated ecosystem health and ecosystem service values, incorporating key factors such as the proportion of exotic tree 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 was significantly negatively correlated with both the health index and per-unit-area service value. Mixed-effects modeling indicated that a 1% increase in exotic tree proportion resulted in a 0.936 decrease in health index and a 1.456×10⁴CNY·hm^-² reduction in service value. The findings highlight the multidimensional impact of exotic mangrove introductions on ecosystem structure and function, and suggest that future restoration efforts should prioritize native species composition, improve water quality, and enhance ecosystem function to support sustainable management of mangrove ecosystems.

Key words: Guangdong mangroves, ecosystem health, ecosystem service value, exotic mangrove species, community structure