基于底栖动物生物完整性指数的黄河干流生态健康评价

黄河为世界上最长的多沙河流,全河段水沙异质性及其生态健康的空间差异明显。本文基于黄河干流全河段44个断面春秋两季(2019年)底栖动物的系统调查数据,构建黄河底栖动物生物完整性评价体系。该体系融入指示水沙过程变化的ASPT指数及EPT分类单元个体相对丰度,且参照点与受损点得分差异显著,适用于多沙河流生态健康评价。评价结果显示:黄河干流亚健康及以上状态的断面占比为秋季(75.0%)高于春季(54.5%);自源区沿河而下,底栖动物生物完整性指数值呈下降趋势;库区断面底栖动物生物完整性指数低于临近自然河段。回归分析表明,黄河干流底栖动物生物完整性指数与盐度、总氮、城镇及农田用地占比呈显著负相关,与林地及草地占比呈显著正相关。本研究结果可为黄河生态保护与管理提供科学依据。

Ecological health assessment of the Yellow River mainstem based on benthic macroinvertebrate index of biological integrity

The Yellow River is the longest heavily sediment-laden river in the world, with significant spatial variation in water-sand heterogeneity and corresponding ecological health. In this paper, based on the systematic survey data on benthic macroinvertebrates from 44 sections of the mainstem of the Yellow River in the spring and autumn of 2019, we constructed a system for evaluating the biological integrity of the Yellow River''s benthic macroinvertebrates. This system incorporated the ASPT index indicative of the changes in water-sand processes and the relative abundance of individuals in the EPT taxonomic unit, and the scores of the reference point and the impaired point differed significantly, which was suitable for the evaluation of ecological health of a heavily sediment-laden river. The results of the evaluation showed that the proportion of sections in the Yellow River mainstem in a sub-healthy state or above was higher in autumn (75.0%) than that in spring (54.5%). The benthic macroinvertebrate index of biological integrity tended to decrease from the source area downstream. The benthic biotic integrity values of sections in the reservoir area were lower than those of the adjacent natural river sections. Regression analysis showed that the benthic index values of biological integrity of the Yellow River mainstem were negatively correlated with salinity, total nitrogen, urban and agricultural land use, and positively correlated with forest land and grassland use. This study can provide a scientific basis for the evaluation, protection and management of the ecological health of the Yellow River.