基于可拓分析与组合赋权法的乐清湾生态系统健康评价

借助GIS和RS技术,结合数字影像数据、社会经济数据和环境监测数据,运用PSR模型分别从陆源压力、环境状态和生物响应3个方面选取18项指标构建乐清湾海湾生态系统健康评价综合指标体系,并利用可拓分析和组合赋权法对乐清湾生态系统健康现状进行综合评价.研究结果表明:春季和夏季乐清湾全湾生态系统健康水平分别呈极差和中等状态,夏季优于春季,整体生态系统健康状况不容乐观.春季乐清湾生态系统健康水平内湾、中湾和外湾分别为极差、优秀和极差,并在空间上呈现出中湾最好,内湾次之,外湾最差的趋势;夏季乐清湾生态系统健康水平内湾、中湾和外湾分别为中等、优秀和中等,健康水平明显优于春季,并在空间上呈现出中湾优于外湾,内湾最差的趋势.人口密度、单位面积COD排放量、自然岸线保持率、有机污染指数、营养水平指数、底栖生物多样性指数和春季初级生产力是制约乐清湾生态系统健康的主要因素.为了改善乐清湾生态系统健康,应加强土地利用监督管理,控制海水养殖强度,提高生活污水处理率,建立湿地自然保护区,同时发展海洋观光旅游等绿色产业.

Evaluation of marine ecosystem health based on extension analysis and combination weighting method in Yueqing Bay, Zhejiang, China

Based on RS/GIS technology in combination with remote sensing image data, environmental monitoring data and social economic data, this study applied the PSR model to construct the ecosystem health comprehensive evaluation index system with 18 evaluation indexes selected from land pressure, environment state and biological response. The extension analysis and combination weighting method were used to evaluate the Yueqing Bay ecosystem health. Overall, the ecosystem health status of Yueqing Bay was extremely poor in spring while moderate in summer. In spring, the ecosystem health status in inner bay, middle bay and outer bay was extremely poor, excellent and extremely poor, respectively, with middle bay the best and outer bay the worst. In summer, the ecosystem health status in inner bay, middle bay and outer bay were moderate, excellent and moderate, respectively, with middle bay the best and inner bay the worst. The crucial constraints of ecosystem health in Yueqing Bay were population density, per unit area COD emissions, natural shoreline retention, index of organic pollutants, index of nutritional level, index of benthic biodiversity and spring primary productivity of phytoplankton. In order to continuously improve the ecosystem health, we should strengthen the land use supervision and management, control the intensity of mariculture, improve the treatment rate of living sewage, establish the wetland nature reserves, and develop green industry such as marine tourism.