Large dams disrupt river ecosystems, causing negative effects on fish assemblages. Few studies, however, have investigated how Neotropical fish diversity responds to river regulation in longer temporal scales. In this study, we used a multi-metric approach to investigated temporal changes in taxonomic and functional fish diversity over 15 years-period following the construction of a large dam in the Upper Tocantins River, Amazon. We analyzed biological and environmental data collected in the impounded area before (2000–2002) and after (2003–2014) river regulation. Diversity metrics responded differently to the impoundment. Some metrics were not affected, as they showed little variation over years, such as fish abundance, species, and trait richness. Other metrics changed significantly between periods, such as taxonomic composition, temporal beta diversity, and trait abundance. Species with traits that are sensitive to hydrological alterations declined in the impoundment, while sedentary species were favored. Assemblage trajectories were variable, but community structure developed into a different state in the impoundment. Landscape variables explained changes in fish dissimilarity over time. In general, our study supports the notion that fish diversity in Amazonian rivers is vulnerable to river damming, but also indicates that different metrics show particular responses to this disturbance.

中文翻译：

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鱼类多样性对河流调控的长期反应：多指标方法

大型水坝破坏河流生态系统，对鱼类群落造成负面影响。然而，很少有研究调查新热带鱼类多样性如何在更长的时间尺度上对河流调节做出反应。在这项研究中，我们使用多指标方法调查了在亚马逊河上游托坎廷斯河建造大坝后 15 年间分类学和功能性鱼类多样性的时间变化。我们分析了在河流整治之前（2000-2002 年）和之后（2003-2014 年）在蓄水区收集的生物和环境数据。多样性指标对蓄水的反应不同。一些指标没有受到影响，因为它们多年来几乎没有变化，例如鱼类丰度、物种和性状丰富度。其他指标在不同时期之间发生了显着变化，例如分类组成、时间β多样性和性状丰度。具有对水文变化敏感的特征的物种在蓄水池中减少，而久坐的物种受到青睐。组合轨迹是可变的，但群落结构在蓄水池中发展成不同的状态。景观变量解释了鱼类差异随时间的变化。总的来说，我们的研究支持亚马逊河流中鱼类多样性易受河流筑坝影响的观点，但也表明不同的指标显示出对这种干扰的特殊反应。景观变量解释了鱼类差异随时间的变化。总的来说，我们的研究支持亚马逊河流中鱼类多样性易受河流筑坝影响的观点，但也表明不同的指标显示出对这种干扰的特殊反应。景观变量解释了鱼类差异随时间的变化。总的来说，我们的研究支持亚马逊河流中鱼类多样性易受河流筑坝影响的观点，但也表明不同的指标显示出对这种干扰的特殊反应。