金沙江下游干流 (水富—宜宾段) 鱼类群落结构

Fish community structure in mainstream of lower reaches of Jinsha River (Shuifu-Yibin section)

  • 摘要: 金沙江下游干流 (水富—宜宾段) 是多种长江珍稀特有鱼类的幼鱼庇护所,也是大型水利工程建设较为密集的地区之一,其鱼类生物多样性受到严重威胁。为评估其鱼类资源现状,于2021—2023年在安边镇、三块石及柏溪镇3个江段开展了10次调查。结果显示,共采集鱼类8目20科50属69种,其中鲤形目最多 (48种);长江上游特有鱼类17种,国家重点保护野生动物7种,外来物种8种。群落优势种以铜鱼 (Coreius heterodon)、瓦氏黄颡鱼 (Tachysurus vachelli)、粗唇鮠 (Leiocassis crassilabris) 为主。生物多样性指数中仅Margalef丰富度指数呈现出时间和空间的显著性差异 (p<0.05)。ABC曲线结果表明,鱼类群落整体处于中度干扰状态,但大个体优势种有增加趋势。聚类分析结果显示,在56.71%的相似性水平上,2021和2022年的鱼类种类较为相似,归为一组;而2023年的种类与历史记录较为相似,归为另一组;与2021—2022年相比,2023年金沙江下游干流 (水富—宜宾段) 的鱼类种类有所增加。建议后续持续开展鱼类增殖放流、控制外来鱼类入侵以及加强科研监测等措施,进一步推动金沙江及长江鱼类种群数量的恢复。

     

    Abstract: The lower reaches of the Jinsha River (Shuifu-Yibin section), a nursery habitat for various rare and endemic fish species of the Yangtze River, are one of the areas with dense construction of large hydrop projects. However, the fish biodiversity in this region is under severe threat. To assess the status of its fish resources, we had conducted ten surveys from 2021 to 2023 in three river sections: Anbian Town, Sankuashi and Baixi Town. The results show that a total of 69 fish species belonging to 8 orders, 20 families and 50 genera were collected, with the Cyiformes being the most abundant (48 species). There were 17 endemic fish species from the upper Yangtze River, 7 species of nationally protected wildlife, and 8 invasive species. The dominant species in the community included Coreius heterodon, Tachysurus vachelli, and Leiocassis crassilabris. Among the biodiversity indexes, only the Margalef richness index showed significant temporal and spatial differences (p<0.05). The ABC curve indicates that the fish community was in a state of moderate disturbance, but with a trend of increasing dominance of larger individuals. Cluster analysis shows that at a similarity level of 56.71%, the species from 2021 and 2022 were grouped together due to their similarities, while the ones in 2023 were more similar to historical records so they were grouped together. Compared with the results from 2021 to 2022, there had been an increase in fish species in the mainstream of the Jinsha River (Shuifu-Yibin section) in 2023. It is recommended that measures such as continuous fish stocking, controlling the invasion of non-native fish species, and strengthening scientific monitoring be implemented to further promote the recovery of fish populations in the Jinsha River and the Yangtze River.

     

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