Abstract: Mangrove wetland is among the wetland ecosystems with the highest biodiversity and production. However, mangrove wetlands are facing serious ecological problems due to human activities and climate change, causing the loss of extend, degradation of ecosystem functions and decline in biodiversity. In this study, mangrove ecosystem health indicators were developed based on the vigor-organization-resilience (VOR) framework, and the health assessment of mangrove wetlands in Jiulong River Estuary (JRE) in South Fujian was performed. The reference standard for each indicator was determined by referring to current standards, history site conditions or range of indicator values within the study area. The weight of each indicator was determined by using expert consultation and the analytic hierarchy process (AHP), and the mangrove health comprehensive index (MHI) was then calculated. The overall MHI value of the JRE mangrove ecosystem was 0.72, indicating a sub-health state. The MHI value showed a spatial variation in the JRE mangrove. The highest MHI value was estimated in Datu Island, followed by Fugong and Haimen Island, and the lowest value was in Zini. The spatial variation in MHI was closely related to the differences in environmental characteristics, human disturbance, invasion degree of Spartina alterniflora, ecological protection and management efforts. Among the VOR components, the resilience value was higher than the organization and vigor values in JRE mangrove, and the mangrove was mainly characterized by low production and reproductive potential, high community diversity and resilience from disturbance, and high vegetation maturity and habitat suitability. At present, the invasion of S. alterniflora is the key threat to the health of the JRE mangrove ecosystem, which has directly or indirectly impacts on ecosystem production, structure and resilience. Therefore, the efforts on S. alterniflora clearance and control should be strengthened in JRE mangrove, to recover the mangrove and tidal flat habitats, to restore wetland bird habitats, to promote the natural restoration of biodiversity and the integrity and stability of the ecosystem as well.

Key words: mangrove, ecosystem health assessment, VOR, Jiulong Estuary