影响水生态系统健康评价生物指标体系的因素与机制

Biological monitoring and assessment are the key methods to assess the current condition of structure and function integrity of aquatic ecosystems, as well as the methods to set up protection and restoration goals. Aquatic biota assemblages based multimetric index (MMI) and observed/expected (O/E) index are worldwide used indicesthat can assess ecologicalcondition of aquatic ecosystems. Though many researches has been proved that biotic assemblages, natural gradients, and sampling efforts could affect the evaluation of variability of integrity of aquatic ecosystems separately, the knowledge of mechanism for the connections among them,and the influence of themon each other and on final ecological indices remain unclear.Using benthic macroinvertebrate and benthic diatom as indicator assemblages collected in two research regions with different natural and anthropogenic gradients, the proposed study aimed at: (1) comparing andevaluating the variation of bioassessment indices using single and combined biological assemblages, (2) exploring the response of biological assemblages on natural and human gradients in two different regions, and (3) explaining how sampling efforts would affect the performance of ecological indices in terms of the variation among reference values associated with natural variables.It is beneficial to clarify mechanism for the influence of biotic assemblages, natural gradients, and sampling efforts on current condition of aquatic ecosystems. It also provides theoretical support foraquatic ecosystems restoration, and protection of aquatic ecosystems and biodiversity.

生物监测和评价是掌握水生态系统结构和功能完整性、确定保护与修复目标的重要方法。基于水生生物群落的多参数和多变量指数是目前水生态系统健康评价广泛应用的方法。虽然较多研究已经表明指示生物类群、自然干扰梯度和采样强度均会影响生态系统完整性评价的结果，但这三者之间相互关系及其对健康评价指标体系影响机制还不明确。本研究拟选择具有典型自然特征和人类干扰梯度的不同流域，以底栖动物和底栖硅藻作为指示生物，开展以下研究：（1）针对单一和综合生物群落开展健康评价，掌握评价结果稳定性的变化规律，（2）探索不同地理区系水生生物群落组成和多样性对干扰梯度的响应模式，（3）根据不同采样强度下不同生物群落对自然梯度的响应，揭示采样强度影响评价指标体系表现力的机理。该研究将明确影响水生态系统健康评价指标体系的因素及其影响机制，为水生态修复和水生生物多样性保护提供技术支持。

水生态系统生物完整性监测和评价，是确定水污染防治和水生态修复和保护目标、保障水生态可持续发展的基础。生物完整性指数评价水生态系统健康不仅与研究区域的自然梯度和人类干扰强度紧密相关，而且受指标生物群落及其采样的影响。项目调查了澜沧江和额尔齐斯河流域共174个样点的底栖动物、水质、生境指标和自然环境梯度及土地利用数据，结合已有渭河流域43个样点的数据。计算了所有样点的生物完整性MMI和O/E指数、及其他群落组成和功能多样性指数，比较了生物评价指数的评价表现力；采样随机森林和广义线性模型等探索生物群落完整性与土地利用及自然环境梯度的关系。（1）不同地理区域水生生物群落对自然环境梯度和人类干扰梯度的响应模式特征研究结果表明，底栖动物群落组成和功能多样性与自然环境梯度紧密相关，且不同生态区底栖动物多样性指数受到不同空间尺度土地利用和理化环境变量的影响；（2）单独或者综合水生生物类群的水生态健康评价结果及其对人类胁迫干扰响应的稳定性和一致性研究结果表明，综合生物群落的MMI指数的评价表现力最优，不同水生生物群落多样性对环境胁迫的响应曲线存在显著差异性；（3）采样强度对评价指标体系表现力的影响规律结果表明，所有MMI和O/E指数的评价变异程度在<200头个体时的变异程度均较大。项目还综述了应用生物完整性指数评价我国河流的生态健康的研究，及蜻蜓目昆虫稚虫Euphaea superba描述。项目共发表SCI论文3篇，EI期刊论文1篇，核心期刊论文2篇。培养硕士研究生1名，国外学术交流2人。