Dams and associated reservoirs cause drastic changes in the composition and structure of ichthyofauna. Therefore, functional groups within a fish assemblage may respond distinctly to such human interventions in rivers. The objective of this study was to evaluate how fluctuations in fish abundance and biomass differ among trophic guilds. Fish were sampled before and after damming four reservoirs, in their inner areas (more heavily impacted areas) and upstream (less impacted areas). To evaluate possible changes, we used a before–after and control‐impact experimental design. Fish were classified into trophic guilds through diet analysis and based on information available from the literature. Six trophic guilds were identified. The effect of periods (before and after damming) and sites (more and less impacted) on abundance and biomass differed among the trophic guilds. Highly specialized trophic guilds, such as herbivores and detritivores, were negatively affected by damming. Invertivores were negatively affected in the impacted area and increased in abundance and biomass in the less impacted sites. The findings of this study show that modifications imposed by damming are reflected in the abundance and biomass of fish trophic guilds, but the degree of such impacts vary according to characteristics of the considered trophic guild.

中文翻译：

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鱼类营养协会对大坝的反应：丰度和生物量的变化

大坝和相关的水库使鱼腥藻的成分和结构发生了巨大变化。因此，鱼群中的功能群可能对人类对河流的这种干预有明显的反应。这项研究的目的是评估营养协会中鱼类丰度和生物量的波动如何不同。在筑坝四个水库之前和之后，在其内部区域（受影响较大的区域）和上游（受影响较小的区域）取样鱼。为了评估可能的变化，我们使用了之前-之后和控制-影响实验设计。通过饮食分析并根据文献中的信息，将鱼类分类为营养协会。确定了六个营养协会。在营养协会中，时期（筑坝前后）和部位（受到的影响越来越小）对丰度和生物量的影响是不同的。筑坝对高度专业化的营养行会（例如草食动物和毁灭动物）产生了负面影响。在受影响的地区，食肉动物受到负面影响，在受影响较小的地区，食肉动物的丰度和生物量增加。这项研究的结果表明，筑坝所造成的改变反映在鱼类营养协会的数量和生物量中，但是这种影响的程度根据营养协会的特征而有所不同。在受影响的地区，食肉动物受到负面影响，在受影响较小的地区，食肉动物的丰度和生物量增加。这项研究的结果表明，筑坝所造成的改变反映在鱼类营养协会的数量和生物量中，但是这种影响的程度根据营养协会的特征而有所不同。在受影响的地区，食肉动物受到负面影响，在受影响较小的地区，食肉动物的丰度和生物量增加。这项研究的结果表明，筑坝所造成的改变反映在鱼类营养协会的数量和生物量中，但是这种影响的程度根据营养协会的特征而有所不同。