上海市滩涂湿地生态系统健康评价及成因分析

ECOSYSTEM HEALTH ASSESSMENT AND CAUSES ANALYSIS OF TIDAL MARSHES IN SHANGHAI

上海沿江沿海地区是我国重要的滩涂湿地分布区,其滩涂湿地生态系统健康对上海乃至长三角地区的生态安全具有重要意义。基于"压力-状态-响应(PSR)"模型,构建了上海市滩涂湿地生态系统健康评价指标体系,采用熵权综合评价法对研究区域生态系统健康状况进行评价,并设定了相应的健康评价分级标准。结果表明:杭州湾北沿边滩、南汇边滩、浦东边滩、宝山边滩、长兴岛周缘边滩、横沙岛周缘边滩、崇明南滩、崇明北滩均处于亚健康状态;崇明西滩处于较健康状态;而崇明东滩和九段沙湿地处于健康状态。过度围垦、环境污染、互花米草(Spartina alterniflora Loisel)入侵等胁迫因子是上海市滩涂湿地面临的主要压力。在多重胁迫因子作用下,近30a来上海滩涂湿地面积锐减,生态系统结构改变,生态功能退化。应重点控制滩涂开发强度,减少污染物排放,并加强对上海市滩涂湿地尤其是大陆边滩的保护,以维护湿地生态系统健康,保障区域生态安全。

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-StateResponse） 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.