Abstract: [Objective] The study was to evaluate the inner and external health pressure of mangrove wetland, to analyze coordination (contradiction or harmony) between health components and their circumstance and future development trends, and to discuss the influential mechanisms of inner health, therefore to develop a scientific model of protection and reasonable use of the mangrove wetland.[Methods] Based on the TM images of 1987, 2000 and 2010, geographical map, topographic map and survey data of community plots, the inner and external health pressure of study area was evaluated. On this basis, using medical health quotient theory for reference and dynamic research methods, the whole health developing trends of mangrove wetland were studied.[Result] 1) The results of inner health were as follows: the community of Excoecaria agallocha + Bruguiera ymnorrhiza showed very healthy; the communities of Rhizophora apiculata + Xylocarpus granatum, R. apiculata and R. apiculata + Bruguiera sexangula showed healthy; the communities of Ceriops tagal, B. sexangula, C. tagal + B. ymnorrhiza, R. apiculata + Sonneratia alba showed basic healthy; the communities of Lumnitzera racemosa + C.tagal and S. alba showed general ill. The comprehensive index of inner health was 0.599 9 indicating basically a healthy and t stable community structure; 2) The influence order of all types of interference on wetland was as follows: forest land loss > sea dyke construction > original habitat damage > Beach enclosure for fish farming > sea level rise > heavy metal pollution in soil. And their contribution rates were 31.37%, 29.41%, 23.53%, 11.76%, 2.94%, 0.98%, respectively. The human interference intensity was much higher than natural disturbance intensity. The heavy metal pollution in soil did not threaten the inner health of mangrove wetland. The interference degree of sea level rise was increasing year by year. The pressure index of external health was 0.816 0, ranked as extreme. 3) The coordination between inner health and external environment: the quotient of overall wetland health (HQ_W=0.735 2) <1, indicating that negative effects of external interference on the mangrove wetland were dominant. [Conclusion] The environmental factors influencing the whole health of mangrove wetland were mainly human disturbance, among which the beach enclosure for fish farming and the sea dyke construction were the most prominent influential factors. Human disturbance directly resulted in the reduction of mangrove resources, the destruction of original beach habitat, the change of topography and geomorphology. These led to the lack of system integrity, the decrement of stability, the reduction of biodiversity, the risk of the extinction for some mangrove species. The impacts of health pressure on the inner health of mangrove mainly exhibited the degradation of mangrove community structure. In horizontal structure, the species number decreased and a part of community types degraded to single species community. In vertical structure, it mainly presented the simple of community level structure and the degradation of height growth. Previous trees and small trees degraded to high density shrubs with the height below 1 m. The environmental conditions were against healthy development of the mangrove wetland. The mangrove wetland tended from basic healthy to general ill. The key measure for the conversion from contradiction to coordination between mangrove wetland and environment was to reduce and control human disturbances such as beach enclosure for fish farming and sea dyke construction.

Key words: mangrove wetland, inner health, external pressure, health quotient, health trend