基于大型无脊椎动物完整性的赤水河健康评价体系构建

作为长江上游珍稀鱼类国家自然保护区的核心区,赤水河流域水系的健康状况虽颇受关注,但相关评价工作却较少。笔者结合现场调查(2016年)和历史数据(2007年),初步构建基于大型无脊椎动物群落的健康评价体系,对赤水河干流和部分支流的不同季节(春季和秋季)和不同河段(上中下游)的健康状况进行评估。指标筛选结果显示:赤水河上游河段在春季和秋季分别包括6、2个核心参数,中游河段分别包括5、4个,下游包括3、2个核心参数。通过四分法将健康状态划分为4个等级:健康、亚健康、一般和不健康。从整体上看,赤水河处于亚健康状态,且春季和秋季河流不同采样点健康状况有所差异,春季健康状况好于秋季。回归分析显示,BOD_5、COD_(Mn)以及NH~+_4-N是影响赤水河健康的主要环境因子。研究所构建的B-IBI评价指标较好地评估了赤水河的健康状况,可作为赤水河流域水体环境监测的有效手段之一。

Construction of Macroinvertebrate Integrity-Based Health Assessment Framework for the Chishui River

Being core of the National Rare and Endemic Fish Nature Reserve in the upper reach of the Yangtze River, the health status of the Chishui River system remains largely unknown. Here, based on comprehensive data sets of field investigation (2016) and historical record (2007), a macroinvertebrate integrity biological index (M-IBI) framework was proposed to evaluate the river''s health conditions both in spring and autumn among reaches, respectively. The final M-IBI framework integrated 6 and 2 key macroinvertebrate metrics in upstream, 5 and 4 metrics in midstream, 3 and 2 metrics in downstream in spring and autumn, respectively. Based the M-IBI scores, the health condition was categorized as 4 levels:very good, good, fair and poor. The assessment results showed that the whole river''s health condition was at good level, and the health condition in spring was better than that in autumn. Regression analysis showed that human-induced nutrients (BOD₅, COD_Mn and ammonia nitrogen) were the main environmental factors affecting the river''s health condition. Overall, the proposed M-IBI framework was suitable to the Chishui River,and could serve as one effective measure of health monitoring in the river system.