Estruturação longitudinal de assembleia de peixes do Rio Madeira

Abstract

Studies of the factors that promoter the distribution of species' are one of the most accepted ways of science for understanding of organization and stability of natural populations. Unveiling these mechanisms is crucial to adopt preservation's actions, which intend ensures permanence of populations on natural ecosystems. Hence, we investigated for five years the ichthyofauna of the Madeira River Basin. Our aim was to understand the origin of the factors involved on organization and stability of fish assemblage along this basin. Therefore, this thesis is divided into three chapters. The first one refers to distribution of the alpha, beta and gamma diversity of fish assemblage from Madeira River, before and after construction of Santo Antonio Hydroelectric Plant. In this chapter, we investigated of hierarchical partitioning of diversity, as a way of understanding the origin of the regional diversity, the division of extension spatial of the study area in sub scales. As a result, we noticed the gamma diversity composition, originated on micro spatial scales and regulated by beta diversity. The second chapter shows a test of the Unified Neutral Theory of Biodiversity on the distribution of abundance of fish species from Madeira River. We investigated the capacity of prediction of this theory on abundance of fish species in a high diversity place. We also compared the adjustment of abundances distribution between the model neutral and model lognormal, which is largely known by your high capacity on natural assemblage. The final chapter refers to functional organization of fish assemblage from Madeira River, published on "Ecology and Biology of fish from Madeira River", a book which compiles ecological and biological informations of the ichthyofauna from Madeira River. In this chapter, we investigated the organization of the species according to their trophic guilds and geomorphological characteristics of the sites where they are inserted. This thesis reveals the way and the mains mechanisms that are responsible for organization and stability of the ichthyofauna from Madeira River Basin, as it proposes measures that can be used for fish species' preservation.