生物多样性导向的再生水补给型城市河道水生态修复效果

Biodiversity-oriented water ecological restoration effect in urban river with reclaimed water supply

  • 摘要: 在再生水补给型河道开展水生态修复并监测分析其效果,有助于提升再生水补给河道的生态健康水平。在北京市萧太后河老河道开展全营养级生态修复并进行为期1年的监测,通过生物群落结构、生物多样性指数、水质分析水生态系统变化。结果表明,虽然试验区经历了水质恶化、水量剧减的双重冲击,但河道水生态、水质仍表现出明显改善。生态修复实施后浮游动物、底栖动物、鱼类、鸟类的物种丰富度分别上升为修复前的6、2、3、2倍。浮游动物、底栖动物、鱼类优势种数量均明显增加,且表现出耐污型向健康指示型的变化。底栖动物、鱼类、鸟类的Shannon-Wiener多样性指数、Pielou均匀度指数、Margalef丰富度指数均有上升;鸟类的优势种表现出季节性变化且已出现猛禽。项目区内总磷浓度平均比项目区外低35%,氨氮浓度平均低31%,总氮浓度平均低30%。综合来看,结构完整的水生态系统具有抵抗外界水质、水量冲击的韧性,且能够起到良好的水质改善效果。各生物群落的多样性指数、群落结构均对水质变化有明显的反馈和指示作用,多个生物多样性指数的综合表征效果更全面、更客观。

     

    Abstract: The monitoring and analysis of water ecological restoration effects are useful to improve the ecosystem health of rivers replenished by reclaimed water. The water ecological restoration covering all trophic levels was conducted, and the community structure, biodiversity indices and water quality were monitored for one year to judge the change of ecosystem health in the old river section of Xiaotaihou River in Beijing. As the results showed, although both the water environmental quality and water quantity suffered great decreasing during the experiment, the water ecological health and water environmental quality in the experimental zone all improved. After ecological restoration, species richness of zooplankton, zoobenthos, fish and birds increased to 6, 2, 3 and 2 times of the previous, respectively. The numbers of dominant species of zooplankton, zoobenthos and fish all increased significantly and the dominant species changed from pollution-tolerant species to a health indicator type. Shannon-Wiener diversity index, Pielou evenness index and Margalef abundance index of zoobenthos, fish and bird all increased. The dominant bird species changed from season to season. The top species of the food chain appeared. The average contents of total phosphorus, ammonia nitrogen and total nitrogen in the experimental zone were 35%, 31% and 30%, respectively, lower than those outside the experimental zone. In a word, the water ecosystem with a complete structure could resist external disturbances such as water quantity and quality changes and improve water environmental quality. Biodiversity indexes and community structures of biological communities could respond and indicate the change of the water environment well. The comprehensive evaluation of multiple biodiversity indexes was more comprehensive and objective than the individual index.

     

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