One of the main impacts on aquatic environments is the alteration of flow regime, usually caused by dam construction. This impact changes the dynamics and functioning of the environment. We aimed to evaluate changes in the composition of functional traits of fish assemblages from 29 reservoirs of different chronological ages. We assessed if there were any alterations in trophic state of these reservoirs according to their ages (chronological variable). Then, we evaluated the relationship between functional traits and environmental/chronological variables. Results showed that reservoir age is a predictor of fish assemblage functional traits composition. In older reservoirs, there was a predominance of omnivorous species, with multiple spawning and parental care. However, herbivorous species, with total spawning and medium size, had their abundance reduced. Also, it was possible to identify the influence of depth and water retention time on the composition of functional traits. By showing that although age has an influence on composition, the intrinsic characteristics of each reservoir are very important in evaluating the impacts of these projects. Therefore, the findings presented provide insights into what may happen to functional traits of fish assemblages with ageing of reservoirs.

中文翻译：

---

年代年龄和水库特征作为新热带水库鱼类组合特征组成的预测因子

对水生环境的主要影响之一是水流状态的改变，通常由大坝建设引起。这种影响改变了环境的动态和功能。我们旨在评估来自不同年代的 29 个水库的鱼类组合的功能性状组成的变化。我们根据它们的年龄（年代变量）评估了这些水库的营养状态是否有任何改变。然后，我们评估了功能特征与环境/时间顺序变量之间的关系。结果表明，水库年龄是鱼类组合功能性状组成的预测因子。在较旧的水库​​中，杂食性物种占优势，具有多次产卵和亲本照顾。然而，草食性物种，总产卵和中等大小，他们的丰度减少了。此外，还可以确定深度和保水时间对功能性状组成的影响。通过表明虽然年龄对组成有影响，但每个水库的内在特征在评估这些项目的影响时非常重要。因此，所提出的研究结果提供了关于随着水库老化而可能发生的鱼类组合功能特征的见解。