In this thesis we aimed to contribute to the ecological knowledge about the Ephemeroptera order in Brazil in order to decrease Wallacean, Prestonian and Hutchinsonian shortfalls related to these organisms. For this purpose, we worked with bibliographic data and field sampling, which resulted in six chapters. We summarized bibliographic information about Brazilian Ephemeroptera studies in the first chapter and for the others, we used data from collections performed in Brazilian Amazonia, also for the last chapter, we have used both dataset from collected and bibliographic source. In the first chapter, we performed a scienciometric analysis about Ephemeroptera studies in Brazil, then we have found the main gaps: absence of studies in some Brazilian states and records of families, need of studies about phylogeny, need of improvement of taxonomic resolution in ecological studies, and deficit of knowledge about environmental variables affecting Ephemeroptera distribution. In the second chapter, we proposed new sampler (circular handnet) and sampling design (150-meters along streams) to be used in ecological studies. We tested in the third chapter the effectiveness of our own methodology, where applied to verify whether 15 subsamples are enough to represent mayflies fauna (instead 20 subsamples), also discontinuos sampling are better than continuous, and if the taxonomic resolution between species and genera are highly concordants. In the fouth chapter, the community was analysed in a regional scale, where we verified differences in environment structure of streams and species composition according to interfluves and scales (local or regional). In the fifth chapter, we tested if River Hypothesis is valid for mayflies communities in Brazilian Amazon, where we found the largest rivers acting as geographic barriers structuring mayflies distribution, as well as the connection of drainage basins also affected Ephemeroptera distribution. Finally, in the last chapter we made a study of case through a new approach of Threshold Indicator Taxa Analysis (TITAN). In this chapter, we found Miroculis as a genus associated to forested areas while Ulmeritoides was associatedrelated to oil palm plantation areas;With this thesis, we increased records and knowledge of Amazonian mayflies, by reducing gaps in relation to distribution (Wallacean deficit), abundance (Prestonian defict) and environmental answers from these organisms (Hutchinsonian deficit).
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