In freshwater ecosystems, macrophyte contribute to habitat heterogeneity with their varying structural forms, ranging from free submerged to rooted species. Macrophytes provide substrates that support fish populations, providing food and refuge from predators, especially in semi-lentic environments, like river floodplains, which tend to provide little shelter for small fish. We investigated how the species richness, abundance, and morphological traits of the fish communities of river floodplains in the Amazon region are affected by the heterogeneity of macrophyte beds, based on the relative contribution of each plant species present in these beds. Simple linear regressions were used to investigate the relationship between macrophyte bed heterogeneity and fish species richness, abundance, and morphological traits, evaluated using a community-weighted mean index analysis (CWM). We recorded 16 aquatic macrophyte species and 21 fish species at 34 study sites. Eichhornia azurea and Eichhornia crassipes dominated the macrophyte beds, while the most abundant fish species were Hemigrammus ocellifer and Laimosemion strigatus. The results of the linear regressions of the heterogeneity of the macrophyte beds were only significant for two morphological traits, both linked to fish locomotion. Our results indicate that the heterogeneity of the macrophyte beds acts an environmental filter for the fish species with a high degree of maneuverability, given that these species are able to swim within the macrophyte structures. Although this does not affect the richness and abundance of the fish, the macrophyte beds favor certain species that use this vegetation during the different stages of their life cycle, which present distinct adaptations. The heterogeneity provided by the aquatic macrophytes is thus important to a range of different fish species, by providing shelter and protection for the smaller species with morphological traits that permit their survival in this environment.

在淡水生态系统中，大型植物以其不同的结构形式（从自由淹没物种到生根物种）促进了栖息地异质性。大型植物提供了支撑鱼类种群的底物，提供了食肉动物的食物和庇护所，特别是在半透镜环境中，例如河漫滩，这些地方往往为小鱼提供很少的庇护所。根据每种植物在这些河床中的相对贡献，我们调查了亚马逊河地区河滩平原鱼群落的物种丰富度，丰度和形态特征如何受到大型植物床异质性的影响。简单线性回归用于研究大型植物床异质性与鱼类物种丰富度，丰度和形态特征之间的关系，使用社区加权平均指数分析（CWM）进行评估。我们在34个研究地点记录了16种水生植物和21种鱼类。凤眼莲和凤眼莲在大型植物床中占主导地位，而最丰富的鱼类是半边o和莱莫西米翁。。大植物床异质性的线性回归结果仅对两个形态特征具有重要意义，这两个形态特征均与鱼的运动有关。我们的结果表明，大型植物床的异质性为鱼类提供了一种环境过滤器，具有很高的可操作性，因为这些物种能够在大型植物结构内游动。尽管这不会影响鱼的丰富度和丰度，但是大型植物床偏爱某些在其生命周期的不同阶段使用这种植被的物种，这些物种具有独特的适应性。因此，水生植物提供的异质性对于一系列不同的鱼类非常重要，