湿地生态系统健康评价指标体系Ⅰ.理论

Establishing an Indicator System for Ecosystem Health Evaluation on Wetlands Ⅰ. A Theoretical Framework

湿地生态系统健康是一个新的研究领域。主要从湿地生态系统指标的概念出发 ,阐述了选择生态系统指标的基本理论 ,分析了湿地生态特征指标体系、湿地功能整合性指标体系和湿地社会政治环境指标体系所包含的基本内涵 ,特别强调了生态系统结构和内在功能是生态特征的主要表现 ,功能整合性是湿地生态系统健康的外在表现 ,同时 ,社会政治环境因素中 ,政策法规 ,总体规划 ,政策保障 ,公众参与程度 ,代际周期的社会公平性 ,个人接受能力 ,团体接受能力等是影响湿地生态系统健康的重要因素。

The ecosystem health of wetland is a newly emerged concept, which refers to the state of a wetland having no impairment to the processes of material cycling and energy flow inside the studied ecosystem. When wetland is identified as a healthy ecosystem, this wetland ecosystem remains resistant or resilient to the long-term and unexpected disturbance caused by natural or human activities and shows diversity, complexity and robustness, because the critical ecological components of the ecosystem are well preserved and exhibit no symptoms. The evaluation of ecosystem health of wetland is aimed to determine the magnitude of the jeopardy to or deterioration of the ecosystem, and deliver an early warning or provide information to the decision-making process on maintaining sustainability of wetland. For evaluating the ecosystem health of a wetland, the selection of the assessment indicators should take account of the dynamics of ecological processes, economic structures and societal dimensions under differing management mechanisms, and incorporate the temporal or spatial scales at study because a wetland is a complex ecosystem with compounding interactions among natural, economic, and social aspects. Here, a suit of principles are put forth for choosing ecosystem indicators, which may depict the attributes or states of the ecological components and represent the management objectives and evaluation targets of a wetland ecosystem. Moreover, these ecosystem indicators are able to explain the natures of structures, functions and variations of the ecosystem and the ecological perturbations. Based on these principles, a theoretical framework is established for designing an indicator system involving the subsets of ecological identity indicators, wetland indicators of functional integrity, and the socio-political indicators associated with wetlands, to evaluate the ecosystem health of wetlands. In details, among the three subsets, the ecological identity indicators exhibiting the structures and intrinsic functions of a wetland ecosystem, include natural state, water balance, water chemistry, biotic safety, and species diversity; the indicators of functional integrity show the external profiles of the ecosystem health of wetland, comprising flood control, microclimate stabilization, water quality maintenance, animal and plant products, and; the socio-political indicators are the important exterior factors imposing effects indirectly on the ecosystem health, and composed of relevant policies and laws, development or conservation planning, policy enforcement, public participation, social equity of intra-generation or trans-generations, and individual or organizational acceptability. In practice, a comprehensive evaluation of the indicators of the three subsets may help determine the states of ecosystem health of wetland.