Niche breadth and habitat preference of Ephemeroptera, Plecoptera, and Trichoptera (Insecta) in streams in the Brazilian Amazon

Despite advances in recent years, there remains a lack of information on the habitat specificity of many aquatic insects, especially for the most recently described taxa and for very diverse regions such as the Amazon. This study evaluates the relationship between niche breadth and habitat specificity of aquatic insects in 219 streams. Local environmental variation in streams impacted by multiple land uses have resulted in distinct assemblages in each region. An Outlying Mean Index analysis was use to evaluate niche position and revealed that environmental changes could favor specialist insects. For example, streams impacted in one of the regions had higher values of depth, dissolved oxygen, percentage of roots, and percentage of wood in the substrate. These conditions contributed to the occurrence of the locally tolerant Hydrosmilodon and Zelusia genera, as well as the locally sensitive genera Harpagobaetis, Leptohyphes, and Traverhyphes. Results showed that some taxa from each regional assemblage occupying less often occupied habitats, and these taxa are represented by few individuals and with a low frequency of occurrence. The knowledge generated here is important for protecting habitats and maintaining the local biodiversity of aquatic systems in the Amazon impacted by multiple lands uses and land conversion activities.