Contrasting responses of β-diversity and functional composition of aquatic insect communities across local to regional scales in Neotropical streams
Supplementary Material from the original research article entitled: “Contrasting responses of β-diversity and functional composition of aquatic insect communities across local to regional scales in Neotropical streams”. Authors: Gilberto Nicacio, Erlane José Cunha, Neusa Hamada and Leandro Juen. This article is a preprint and has not been certified by peer review available on bioRxiv (DOI: 10.1101/2020.09.14.297077). ARTICLE INFORMATION: In this manuscript, we tested variation in community composition of Ephemeroptera, Trichoptera, and Plecoptera between regions with distinct ecological gradients known as Amazonian interfluves. We calculated beta diversity by computing Sorensen dissimilarities and evaluated environmental factors interact to structure taxonomical and functional composition in streams. Thus, we addressed discussion about effects of habitat structure and geographical distances considered as the main determinants for driving species diversity and distribution. Then, our results provide empirical support for patterns of beta diversity and functional composition of aquatic insect assemblages between regional contexts. In summary, species replacement generated most of community dissimilarities and were associated with geographical distances and environmental variation.
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We evaluated 16 sites (first- and second-order streams) located in two pristine forested regions in the Floresta Nacional do Tapajós and Floresta Nacional de Carajás, both in Pará State, Brazil. Sampling was done in June 2015 and September/October 2015. The sampled sites at Flona Tapajós were streams with sandy beds distributed in lowland riverine networks (Table S1 in Supplementary Material). In contrast, the sites in the Flona Carajás region were streams with rocky beds, where the landscape has a high elevation range, from sea level at sites adjacent to the Amazon River to 600m above sea level in the Serra dos Carajás uplands. To investigate the patterns in functional composition among assemblages, a categorical genus-traits matrix (of EPT functional composition) was developed using traits from the available literature (see References in Electronic Supplementary Material). Six trait groups were then computed to express 20 trait states for each taxon identified using data available in the current literature. Then, trophic traits (i.e., ‘food’ and ‘guilds’), respiration modes, morphological adaptations (body shape and specific adaptations), and mobility were grouped (see the trait matrices in Tables S2, S3 and S4 in Supplementary Material).