Nicho e endemismo em ambientes entremarés recifais: uma abordagem utilizando isótopos estáveis
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2018-03-29
Autores
Andrades, Ryan Carlos de
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Universidade Federal do Espírito Santo
Resumo
Although the concept of ecological niche can vary according, its essence lies in understanding the fit of organisms living under specific abiotic and biotic conditions. This thesis examined the coexistence of marine organisms using stable isotopes from an Eltonian niche view, though many aspects also cover Grinnellian and Hutchinsonian perspectives. The surveys were conducted in six oceanic and coastal intertidal environments of the Brazilian Province: Rocas Atoll, Fernando de Noronha and Trindade Island and Salinópolis (Pará state), Jericoacoara (Ceará state) and Anchieta (Espírito Santo state) representing three oceanic and three coastal sites, respectively. The chapters hereafter reveal the importance and ecological functioning of intertidal habitats from a niche and endemism perspective. The first chapter is an introductory chapter, whereas the second highlights the high fish endemism rates found worldwide in oceanic islands intertidal environments, drawing attention to the fragility of this ecosystem. Chapter three is a fish community structure study, which reveals the dominance of intertidal communities by small-sized and resident species. Also, endemic species were abundant in the islands and key to structuring communities. The fourth chapter evidenced through modeling spatial data and stable isotopes analysis (G13C and G15N) that food chains in islands are longer and more complex than in coastal sites and that cryptobenthic species are the most vulnerable species to intra and interspecific competition pressures. Chapter five focused on the potential impacts of an invasive species on island intertidal reef communities. Invader density data and stable isotopes signatures in coastal sites were used to simulate the impact on the islands. We verified that mostly intertidal species are vulnerable to a hypothetical invasion, however endemic species vulnerability is especially worrisome due to low competition resistance and small life territory. The sixth chapter reports on the unexpected death by desiccation of resident and non-resident intertidal fishes, highlighting the harsh conditions that these species experience. Chapter seven presents a set of length-weight and length-length relationships for Brazilian island fishes, including endemics. Summarizing, the niche performed by intertidal species revealed, for the first time, island communities to have high trophic diversity and rich resources at the base of the food chain and endemic species fragility in face of imminent biological invasions and sea-level rise.
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Isotopic niche , Tidepool , Poças de marés , SIBER
Citação
ANDRADES, Ryan Carlos de. Nicho e endemismo em ambientes entremarés recifais: uma abordagem utilizando isótopos estáveis. 2018. 127 f. Tese (Doutorado em Biologia Animal) - Universidade Federal do Espírito Santo, Centro de Ciências Humanas e Naturais, Vitória, 2018.