Abstract:

Regions along the Yangtze River in Shanghai are the main distribution area of tidal marshes in China. The ecosystem health has significant meaning for ecological safety in Shanghai and even the Yangtze River Delta. Ecosystem health assessment was accomplished through establishment of index system of PSR (PressureStateResponse) and entropy fuzzy comprehensive evaluation model, and the quality grading standards was worked out. It is divided into illness, general illness, subhealth, lesshealth and health. Results showed that Hangzhou bay beach, Nanhui beach, Pudong beach, Baoshan beach, Changxing beach, Hengsha beach, Chongming South beach and Chongming North beach were in the state of subhealth, Chongming West beach was in lesshealthy state, the comprehensive health index of Chongming Dongtan and Jiuduansha were in the state of health. Peripheral islands beaches were generally healthier than mainland beaches. Comprehensive health degree was a comprehensive reflection of three mutually causal relationships between pressure health index, state health index and response health index. Pressure health index of the mainland beaches was lower than that of the peripheral island, and state health index of Jiuduansha and Chongming Dongtan was higher, and response health index of Chongming Dongtan and Jiuduansha was also higher than the others. Investigation and analysis results showed that the environment of tidal marshes was under main stresses including highintensity enclosure, environmental pollution and biological invasion. Tidal marshes area was reduced, community structure was changed and ecological function was degraded under multiplestress for nearly 30 years. In order to maintain ecosystem health and ecological security, combination of dynamic protection and utilization should be used on tidal marshes conservation management. Controlling development intensity and pollutant emission, strengthening the protection of tidal marshes especially mainland beach should to be key focus. Given that reducing the beach area is not due to human factors as a baseline, the legal system building should be strengthened as well as the efforts to recover tidal marshes ecosystem. Beyond that, promoting the control and management of invasive species can relieve the stress to the maximum extent