Here we analysed the taxonomic and functional diversity of microcrustaceans along a horizontal gradient from the littoral to pelagic zones of a marginal lake. We hypothesized that in the littoral zone, occupied by high density of macrophytes, the taxonomic and functional diversity would be higher because the macrophytes coverage offers greater availability of niches for microcrustaceans. The individuals were collected in 10 sampling stations in a horizontal transect from littoral to pelagic zones of the lake. The community structure was determined by three classic measures: species richness, diversity and abundance of organisms. For the measurement of functional diversity, we identified the functional groups and calculated the functional group richness, the indexes of functional richness (FRic) and functional evenness (FEve). The abundance of microcrustaceans was higher in littoral zone, while the species richness and diversity did not differ between the zones of the lake. Cyclopoid copepod nauplii predominated in the region with macrophytes, while adult forms increased in pelagic zone. For functional diversity, the community was divided in six functional groups, with bosminids dominating the lake. Values of FRic and FEve did not differ between the regions of the lake, but the functional groups were more diverse in the littoral zone. The habitat complexity offered by macrophytes in the littoral zone provides greater diversification of ecological niches for microcrustaceans, resulting in more diverse functional groups. Finally, functional diversity proved to be a more accurate tool in detecting spatial variations in the microcrustacean community when compared to the taxonomic diversity.

中文翻译：

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大型植物定植的新热带湖泊中沿水平梯度的微甲壳类功能群

在这里，我们沿着从边缘湖的沿海到远洋区的水平梯度分析了微甲壳动物的分类学和功能多样性。我们假设在沿海地区，被高密度的大型植物占据，分类和功能的多样性会更高，因为大型植物的覆盖范围为微型甲壳类动物提供了更大的生态位。这些个体被收集在从湖泊沿岸到远洋区域的水平断面的 10 个采样站中。群落结构由三个经典指标决定：物种丰富度、多样性和生物体丰度。对于功能多样性的测量，我们确定了功能组并计算了功能组丰富度、功能丰富度指标（FRic）和功能均匀度（FEve）指标。滨海带微甲壳类的丰度较高，而湖区之间的物种丰富度和多样性没有差异。该地区以圆环类桡足类无节幼体为主，有大型植物，而在远洋区成虫数量增加。对于功能多样性，该社区分为六个功能组，bosminids 占主导地位的湖泊。FRic 和 FEve 的值在湖区之间没有差异，但功能组在沿海地区更加多样化。沿海地区大型植物提供的栖息地复杂性为微型甲壳类动物提供了更大的生态位多样化，从而产生了更多样化的功能群。最后，