Macroinvertebrate-based assessments in Brazilian freshwaters: A systematic review

Freshwater ecosystems are increasingly threatened by different human stressors, thereby jeopardizing aquatic biota. Macroinvertebrates are one of the most common bioindicators used worldwide to assess the biological condition of ecosystems. In this study, we systematically reviewed the literature on the use of macroinvertebrates as biological indicators in freshwater ecosystems in Brazil, highlighting the impacts of human activities. Following Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, we analyzed 175 articles published up to June 2023 extracted from the Scopus and Web of Science databases. We summarized information on temporal and spatial trends, type of aquatic environment, biological metrics used, taxonomic levels, and sources of anthropogenic stressors. We found an increase in the number of studies over time and a biased geographical distribution, in which the Paraná hydrographic region was the most studied by far. Lotic systems were the most common type of environment, and most studies identified individuals at the family level and used metrics such as taxonomic richness, diversity, and abundance in contrast to functional, morphological, or physiological metrics. The main reported stressors were water quality and habitat changes, often associated with urbanization and agriculture. To support effective monitoring and conservation policies in a megadiverse country, it is important to improve knowledge of human stressors on freshwater communities, and the findings of this study are crucial for understanding how human activities have impacted freshwater communities in tropical ecosystems. • Macroinvertebrate-based freshwater studies in Brazil are not equally distributed geographically. • Taxonomic and abundance metrics are the most commonly used in bioassessments. • Urbanization and agriculture are the main human stressors.