Explorando regras de montagem e partição dos componentes da diversidade da assembleia de peixes.

Abstract

One of the most fascinating challenges in ecology and conservation biology is understanding the factors that determine patterns on species distribution and coocorrence. Generally, this understanding occurs through taxonomic studies of species assemblage. However, functional attributes of species provide informations about resources use and requirement of species habitat, and so it has potential to elucidate processes that govern these patterns in local, regional and continental scales. Furthermore, with functional atribbutes it is also possible to assess changes in species traits along time and space using metrics of functional dissimilarity, i.e., functional β-diversity. So, this thesis aimed to explore: (i) assembly rules and (ii) partitioning components of β-diversity of fish assemblage in a Neotropical floodplain. Initialilly, nine environments were sampled quarterly over 12 years (2000-2011),and posteriorlytwenty environments were sampled quarterly in years 2000, 2001, 2010 and 2011. This thesis demonstrated that there are distincts assembly processes of fish assemblage acting in the upper Paraná river floodplain. Moreover, when it is assessed that a specific assembly process occurs in the environment, it is need to be cautious, because scale can mask the actual process that the assemblage is going to settle down. Additionally, describing spatial patterns of functional and taxonomic β-diversity and analysing their determinants is fundamental to assess their temporal tendencies in the context of environmental changes induced naturally or not. In this sense, turnover component was the main responsible by changes in β-diversity of fish in floodplain, and functional and taxonomic β-diversity varied in space and time, mainly due to environmental alterations. That would be an indicative of environmental filters are importants as assembly rules on structuring of functional characteristics of fishes in floodplain. Finally, both approaches, functional and taxonomic, capture different aspects of biodiversity and provide complementary mechanisms to understand human impacts over world ecosystems. Thus, future studies of fish assemblages, in floodplain and other aquatic ecosystems, need to test if changes in patterns of taxonomic diversity follow changes in functional diversity and to evaluate how two components of β-diversity respond to biotic and abiotic changes.