Response of aquatic insect assemblages to the activities of traditional populations in eastern Amazonia

Abstract

This study investigated the effects of activities carried out by traditional populations on aquatic ecosystems using the assemblages of Ephemeroptera, Plecoptera, and Trichoptera insect orders, and identified fluvial habitat characteristics modified by the disturbances. We surveyed two groups of streams—17 streams representing control conditions (CON) and 17 streams influenced by traditional population settlements (TPO). Genera richness and abundance of individuals did not vary between groups. With regard to physical habitat metrics, the percentage of leaf litter, amount of woody debris in the channel, proximity to farming, percentage of slow water in the channel, and the mean riparian vegetation cover all influenced benthic macroinvertebrate assemblages. Considerable differences were found in genera composition between the two groups. The genera Ulmeritoides, Miroculis, and Brasilocaenis were associated with the CON group, and Macronema and Campsurus with the TPO group. We conclude that even small-scale impacts, such as those performed by traditional Amazonian populations, can have major effects on aquatic biota, which reiterates the fragile nature of these ecosystems and emphasizes the need for adequate management of these activities.