Efeitos da urbanização na diversidade de peixes de riachos da Mata Atlântica
Guinato, Rayssa Bernardi
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Researching biodiversity and understanding environmental responses to anthropic modifications considering multiple system scales and particularities have become even more urgent. A way of understanding community’s setting processes and its biological responses consists of using diversity measures which cover different aspects about the composition, funcionality and the evolutive history of the environment. Considering that the changes caused by urbanization reflect in fish communities, we hypothesize that urbanization functions as an environmental filter, selecting species and influencing the diversity of ecosystems, therefore, the aim of this study was to compare through taxonomic diversity and functional indexes, stream fish communities which live either in rural and urban environments along the Upper Paraná River basin, located in the Southeast region of Brazil. In order to accomplish that, it was written two chapters about 48 different stream’s icthyofauna in the Atlantic Forest region: out of the total, 30 and 18 streams are located in rural and urbanized environments, respectively. In CHAPTER I, it was evaluated the taxonomical diversity among fish communities by measuring total specie richness (S), average richness (S ̅), estimated richness (S*), the Shannon-Wiener’s indexes of effective species (e^H') as well Simpson’s dominance (1/D). We observed that the taxonomical indexes were higher to the rural environments, indicating that, in terms of taxonomic, the rural environment diversity is higher when compared to the urban zones. In addition, in CHAPTER II, functional diversity standards of the communities were compared among rural and urban environments by analyzing food and locomotion morphological atributes of fishes. This index were adapted to functional quantitative indexes as richness (Fric), equability (Feve), dispersion (Fdis), divergency (Fdiv), specialization (Fspe) and originality (Fori). Rural environment presented higher functional dispersion than urban zones, whereas, streams which are inserted into urbanized environments showed a higher specialization and functional originality. Thus, it is evident that urban environments present a more homogeneity in their function distribution along the system, altough these functions are more original and unique. As final results we have gotten differences between taxonomical and functional diversity standards which happened due to the anthropic modifications into the system; these modifications, therefore, can work as important environmental filters within the organization of stream’s fish communities.