生态阈值存在于各种生态系统中，在查阅国内外相关文献的基础上，通过对生态阈值的理论研究及在森林、草原、湿地、湖泊和河流等方面实践应用进行总结分析，指出生态阈值在河流生态系统研究中的不足之处。针对在高污染负荷下修复退化的水生态系统中，开展生态修复阈值的研究寥寥无几，关于界定河流水生态修复阈值指标体系的研究尚未出现。通过分析阈值在河流水生态修复中的重要性，指出河流水生态修复阈值确定是退化水生态修复的基础，为区域针对性修复水体提供科学依据和决策支持，更是水环境管理发展的迫切需求。在此基础上，从新的角度探讨和提出河流水生态修复阈值概念。河流水生态修复阈值，是依据河流生态系统自然属性和河流功能以及区域社会经济发展的需求来界定退化到何种程度的水生态系统需要进行修复，退化现状程度大于此修复阈值，则需进行人工修复；退化现状程度小于修复阈值，则无需进行修复。通过对指标体系构建原则、筛选方法及阈值计算方法的总结，提出河流水生态修复阈值确定技术路线，采用频度分析法和理论分析法相结合，从影响河流修复的6大要素(物理结构、水文条件、水质状况、水生生物、河流功能和社会经济)初步构建了河流水生态修复阈值界定指标体系及阈值计算方法体系，为下一步河流水生态修复阈值指标体系的定量筛选与阈值计算奠定了基础。%Ecological threshold exists in all kinds of ecological systems. Deficiencies on ecological threshold research in river ecological system were pointed out based on reviewing relevant literatures and analyzing theory researches and practices on forest, grassland, lake, wetland and river ecological threshold. For the restoration of degraded river ecosystems in the high pollution load, there were very few study on the threshold of ecological restoration. The studies on index system of river ecological restoration threshold had yet appeared. By analyzing the importance of threshold in river ecological restoration, it pointed out that the determination of the river restoration threshold was the basis of degraded river ecological restoration and provided a scientific basis and decision support for the area to restore the river ecosystem. What’s more, it was urgent needs for the development of the water environment management. On the basis, it put forward the river ecological restoration threshold concept which was to define to which degradation extent should the river ecological systems need to be restored according to river ecosystem natural properties and functions of river and needs of regional socio-economic development, If the degree of degradation were more than the ecological restoration threshold, it will need manual restoration. Otherwise, it will not need restoration. Through summarizing index system construction principles, screening methods and threshold calculation methods, this paper put forward the technical route of river ecological restoration threshold. Combining frequency analysis method with theory analysis method, index system and threshold calculation method system of river ecological restoration threshold were initially built on six elements (physical structure, hydrological conditions, water quality, aquatic organisms, stream function and social economic) which influenced river restoration. This laid the foundation for next quantitative screening and threshold calculation of river ecological restoration threshold index system.
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