2026-03-312026-03-312026-02-27ALVES, Maria Alana Reis. Diversidade alfa e beta de macroinvertebrados aquáticos de microhabitats da bacia do Chumucuí, nordeste paraense. Orientador: Colin Robert Beasley, Coorientadora: Jaqueline da Conceição Souza Feitosa. 2026. 40 f. Trabalho de Curso (Licenciatura em Ciências Biológicas) – Faculdade de Ciências Biológicas. Instituto de Estudos Costeiros, Campus Universitário de Bragança, Universidade Federal do Pará, Bragança-PA, 2026. Disponível em: https://bdm.ufpa.br/handle/prefix/9423. Acesso em: .https://bdm.ufpa.br/handle/prefix/9423Tropical streams are highly environmentally heterogeneous, as reflected in the diversity of microhabitats that structure aquatic communities and regulate fundamental ecological processes, such as macronutrient cycling and energy flow. Among the organisms associated with these environments, aquatic macroinvertebrates play a central role in the decomposition of organic matter, energy transfer between trophic levels, and the maintenance of lotic ecosystem functioning, in addition to being widely used as bioindicators of environmental conditions. In this context, the present study aimed to evaluate the alpha and beta diversity, the structure of the aquatic macroinvertebrate community, and its relationship with environmental variables and the Habitat Integrity Index (HII) in different microhabitats of streams in the Chumucuí River microbasin, in the northeast of the state of Pará. The study was conducted in nine streams, eight of which were first-order and one second-order, in which five types of microhabitats were sampled: leaf litter deposited on the bed, rapids, sand and gravel areas, roots, and backwaters. Sampling took place during the dry season of 2023, using a Surber sampler. Alpha diversity indices of fauna were analyzed and modeled using HII, beta diversity based on presence/absence and abundance, redundancy analysis (RDA), and identification of indicator taxa. A total of 6,616 individuals distributed across 74 taxa of aquatic macroinvertebrates were recorded. The results indicated variations in alpha diversity among microhabitats, with lower values of richness and abundance associated with the sand and gravel microhabitat, which was characterized by greater dominance of a few taxa. Beta diversity values indicated low to moderately high heterogeneity, predominantly explained by the replacement of taxa between microhabitats. RDA revealed that environmental variables related to substrate, organic matter, and canopy cover (oxygen and temperature) gradually influence the structure of the macroinvertebrate community, without the formation of welldefined clusters. HII showed a positive relationship with macroinvertebrate diversity in structurally more complex microhabitats. The identification of indicator taxa reinforced the importance of specific microhabitats for maintaining regional diversity. The results show that microhabitat heterogeneity and environmental integrity are key factors in shaping aquatic macroinvertebrate communities and maintaining ecological processes in tropical streams.Acesso AbertoMacrofauna bentônicaRiquezaAbundânciaÍndice de Bray-CurtisHeterogeneidade ambientalIntegridade do habitatRiachos tropicaisBenthic macrofaunaRichnessAbundanceBray–Curtis indexEnvironmental heterogeneityHabitat integrityTropical streamsCNPQ::CIENCIAS BIOLOGICAS::ECOLOGIA::ECOLOGIA APLICADATrabalho de Curso - Graduação - MonografiaAttribution-NonCommercial-NoDerivs 3.0 Brazil