黄河干流水生态系统结构特征沿程变化及其健康评价

根据2008年黄河干流刘家峡以下河段水生态调查资料,分析了黄河干流水生态系统理化性状和生物群落结构的沿程变化。参照20世纪50和80年代水生态调查资料,对比了黄河干流水生态系统几十年来的变化情况,并分析了变化的原因。通过建立黄河水生态系统健康评价指标,对黄河干流各河段的水生态系统健康状况进行了评价,揭示了黄河水生态系统的现实状况。研究结果表明:由于自然和人类活动影响的差异,黄河干流水生态系统结构特征沿程分布差异比较大;2008年黄河干流水生态状况与20世纪50、80年代相比,除底栖动物外,其它生物种类和数量均下降明显;黄河水生态系统健康状况不容乐观,干流大部分河段生态系统的结构和功能发生了较大的变化,部分生态功能丧失。

Change of structural characteristics and health assessment of aquatic ecosystems along the mainstream of the Yellow River

Based on aquatic ecological survey data of the Yellow River following Liujiaxia in 2008, with reference to ecological survey data of the Yellow River respectively in 1950s and 1980s, this paper analyzes the change regarding physical and chemical properties of the Yellow River aquatic ecosystem in the mainstream and the change of biocoenosis structure along the mainstream, has a contrast to historical changes of the aquatic ecosystem over the last few decades and gives the causes of the changes; it also establishes the ecosystem health assessment index of the Yellow River, and evaluates the Yellow River aquatic ecosystem, thus revealing the actual status of the Yellow River aquatic ecosystem. The results show that (1) due to the different impacts of natural and human activities, there is a significant difference in structural characteristics of aquatic ecosystems along the Yellow River; (2) comparing to 1950s and 1980s, in addition to benthic animals, the species and number of the other aquatic animals decreased significantly in 2008; (3) the Yellow River aquatic ecosystem health is not optimistic, and river ecosystem structure and function of the majority of sections in the mainstream undergoes a significant change, even losing partial ecological functions.