Estrutura funcional de assembleias de peixes em sistemas de drenagens de águas claras da Bacia Amazônica, Brasil

Abstract

Understanding the mechanisms associated with the functional structure of ichthyofauna and biotic responses to environmental changes in aquatic ecosystems caused by climate change and anthropogenic actions associated with food production and mineral exploration is a challenge for science, especially in poorly studied environments, such as clear water drainage systems in the Amazon Basin. In this context, the objectives of the thesis were: i) to compile information regarding the knowledge of the functional structure of fish assemblages in clear-water Amazonian rivers; ii) to evaluate to what extent the structure of fish assemblages is related to environmental variables and how assemblages are structured in a clear-water river at different phases of the hydrological cycle; iii) to evaluate and analyze the effect of seasonal variations in water levels and local environmental variables on the functional structure of fish assemblages and their life strategies. This study showed that changes occur in the structure of the ichthyofauna and in the limnological characteristics in association with the periods of the hydrological cycle. Therefore, it is essential to monitor this evidence, since knowledge of factors such as river level, dissolved oxygen, temperature and turbidity that affect the structure of fish assemblages and the high degree of endemism in the basin is essential for the development of management measures that aim to guarantee the integrity of biological assemblages. Knowledge of environmental variables that influence the structure of fish assemblages in the present study is important, as it will allow the adoption of measures to maintain variations and natural balance in aquatic ecosystems. In addition, our results allowed the understanding of the functional structure and seasonal hydrological influences on fish assemblages in clearwater rivers, and also provide secondary data for ichthyofaunal studies and definitions of conservation and restoration policies in conservation units in the Amazon basin.