| 摘要: |
| 河流具有独特且复杂的树枝状等级性网络拓扑结构，使得河流连通性和生境异质性在不同河网位置上存在明显差异。长期以来，河流生态系统通常被视为局部或线性结构进行研究，忽略了河网位置对群落构建等生态过程的影响。本研究以具有复杂网络结构和自然流态的赤水河为研究区域，探索了河流网络位置对底栖动物α、β多样性和群落构建过程的影响。其中，α多样性使用物种数、Shannon-Wiener多样性、Simpson多样性和Pielou均匀度指数来度量；β多样性使用S?rensen相异性指数 (βs?r) 和Bray-Curtis相异性指数 (dBC) 来表征，并将其分割为置换 (turnover) 和嵌套 (nestedness) 两种组分；群落构建过程采用冗余分析 (Redundancy Analysis) 和变差分解 (variation partitioning) 来实现。结果显示：1) 赤水河全流域底栖动物群落主要受环境过滤驱动；2) 河流网络位置塑造着赤水河底栖动物的多样性格局和群落构建过程。干流群落主要受环境过滤的影响，而支流群落则受到空间限制和环境过滤的共同作用，该发现质疑了河流网络位置假说 (Network Position Hypothesis, NPH) 在赤水河流域的适用性；支流的α多样性明显高于干流，而干流的β多样性则显著高于支流；β多样性主要由置换组分构成，这表明尽可能多地保护不同位点和生境是维持底栖动物物种多样性的重要举措。本研究有助于深入理解复杂河网影响下底栖动物的物种共存与维持机制，为提出适用于我国亚热带季风区河网的新假说提供了视角，为长江上游水生生物保护区选址和设计提供了参考和依据。 |
| 关键词: 河网位置 底栖动物 群落构建 β多样性 赤水河 |
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| The Effects of River Network Position on Benthic Macroinvertebrate Diversity and Community Assembly in the Chishui River |
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Chen Zhanyan1, Mo Yangxin2, Zhao Xianfu3, Jiang Yinan2, Zhang JunQian2, Bai Xue2, Chen Bi1, Wang Li1, Li Zhengfei2
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1.Kweichow Moutai Co,Ltd;2.Institute of Hydrobiology,Chinese Academy of Sciences;3.Institute of Hydroecology,Ministry of Water Resources and Chinese Academy of Sciences
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| Abstract: |
| Rivers possess unique and complex branching hierarchical network topology, which leads to noticeable differences in connectivity and habitat heterogeneity across different sections of the river network. Historically, river ecosystems have been studied as local or linear structures, overlooking the influence of river network positions on ecological phenomena, such as community assembly. We focused on the Chishui River, which has a complex network structure and natural flow regime, to explore the effects of river network positions on species diversity (α and β diversity) and community assembly of macroinvertebrates. α diversity is measured using species richness, Shannon-Wiener diversity index, Simpson diversity index, and Pielou evenness index. β diversity is characterized using the S?rensen dissimilarity index (βs?r) and Bray-Curtis dissimilarity index (dBC), which are further partitioned into turnover and nestedness components, respectively. Community assembly is assessed using Redundancy Analysis (RDA) and associated variation partitioning. We found that: 1) Macroinvertebrate communities in the entire river basin are primarily regulated by environmental filtering. 2) River network positions affect the diversity patterns and community assembly processes in the Chishui River. Mainstream communities are primarily influenced by environmental filtering, while tributary communities are structured by both spatial constraints and environmental filtering. These findings challenge the applicability of the Network Position Hypothesis (NPH) in the Chishui River basin. Additionally, α diversity is significantly higher in tributaries compared to the mainstream, whereas β diversity is significantly higher in the mainstream. The beta diversity of macroinvertebrate communities is mainly composed of turnover, suggesting that protecting different sites and habitats is crucial for maintaining regional species diversity. This study provides insights into the mechanisms of species coexistence and maintenance in benthic communities under the influence of complex river networks and contributes to the development of new hypotheses applicable to river networks in subtropical monsoon regions in China. It also provides reference and basis for site selection and design of biological protection zones in the upper reaches of the Yangtze River. |
| Key words: river network position macroinvertebrate community assembly β diversity Chishui River |
