Patterns and metacommunity structure of aquatic insects (Trichoptera) in Amazonian streams depend on the environmental conditions

Species distribution depends on dispersal ability and species responses to the environment, where the anthropogenic landscape can facilitate or difficult for them to track the environmental gradients. Therefore, we assess how drivers and distribution patterns from Trichoptera metacommunity change in anthropogenically disturbed streams. We expected that, changes in land use and land cover increase the environmental heterogeneity among disturbed sites and promote the turnover of Trichoptera genera, since the importance of environment and space to the disturbed metacommunity should be higher in relation to the undisturbed sites. We sampled 62 stream sites in the Eastern Amazonia, classified as undisturbed or disturbed, assessing the environmental heterogeneity through Multivariate Dispersion analysis, the importance from environment and space through partial Redundancy Analysis and the metacommunity patterns by the Elements of the Metacommunity Structure. We showed that Trichoptera metacommunity was mainly determined by environment in both site groups, with high contribution from space only on disturbed sites, showing higher environmental heterogeneity. However, the distribution patterns differed between the site groups, being mostly nested or random on undisturbed sites and turnover based on disturbed ones. This may be related to the multiple impact types that simultaneously influence disturbed sites, increase heterogeneity, and affect distribution patterns.