Reservoir shorelines are usually colonized by submerged macrophytes, which may select fish species that are able to thrive in these environments, consequently influencing the functional diversity of fish assemblages. However, there are also intense anthropogenic activities in these environments (macrophyte removal), which may also affect the functional diversity of fish communities. Thus, this study aimed to evaluate the influence of anthropogenic activities and habitat complexity provided by submerged macrophytes on the functional diversity of the ichthyofauna of reservoirs. Fish sampling was carried out at three stations in marginal areas of the Itaipu reservoir, located in sites near and apart from artificial sand beaches and with and without submerged macrophytes. The functional traits used were morphometric measurements taken from sampled fish (intraspecific traits), which were used to calculate three functional diversity indices: functional richness, evenness, and divergence. In general, no patterns were found for the functional diversity indices concerning macrophyte removal (among sampling sites). In contrast, habitat complexity did influence the functional diversity of fish assemblages, with results differ depending on macrophyte density. While functional richness was higher with greater habitat complexity, the opposite was evidenced for functional evenness and divergence. These findings reinforce the importance of different habitats for the maintenance of fish functional diversity in marginal areas of reservoirs. They also contribute to the implementation of macrophyte management for the maintenance of fish biodiversity and the establishment of priority areas for conservation and tourism in these environments.

水库海岸线通常被淹没的大型植物定殖，这些植物可能会选择能够在这些环境中繁衍生息的鱼类，从而影响鱼类群落的功能多样性。然而，在这些环境中也存在强烈的人为活动（大型植物去除），这也可能影响鱼类群落的功能多样性。因此，本研究旨在评估人为活动和沉水大型植物提供的栖息地复杂性对水库鱼类功能多样性的影响。在伊泰普水库边缘区域的三个站点进行了鱼类采样，这些站点位于人工沙滩附近和远离人工沙滩的地点，以及有和没有被淹没的大型植物。使用的功能性状是从采样鱼（种内性状）中获取的形态测量值，用于计算三个功能多样性指数：功能丰富度、均匀度和发散度。一般来说，没有发现有关大型植物去除的功能多样性指数（采样点之间）的模式。相比之下，栖息地的复杂性确实影响了鱼类组合的功能多样性，结果因大型植物密度而异。虽然栖息地复杂性越高，功能丰富度越高，但功能均匀性和发散性则相反。这些发现强化了不同栖息地对维持水库边缘区域鱼类功能多样性的重要性。