Uso dos recursos alimentares e estrutura trófica da ictiofauna do reservatório de Manso (bacia do rio Cuiabá, MT, Brasil) em diferentes períodos da fase de colonização.

• Autor(a) principal: Gimenes, Michele de Faveri
• Data de Publicação: 2011
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Estadual de Maringá (RI-UEM)
• Texto Completo: http://repositorio.uem.br:8080/jspui/handle/1/5113
• topic: Peixes de água doce; Alimentação; Dieta alimentar; Estrutura trófica; Amplitude de nicho; Sobreposição da dieta; Reservatório Neotropical; Cuiabá, Rio, Bacia; Mato Grosso; Brasil.; Niche breadth; Niche overlap; Trophic structure; Neotropical reservoir; Cuiabá River; Mato Grosso; Brazil.; Ciências Biológicas; Ecologia

The Manso Reservoir (Cuiabá River basin, MT, Brazil) was closed in November 1999, and in different periods of colonization phase, in order to assess how fishes exploited food resources, and if there was variation in the trophic structure of fish fauna, considering the influence of availability of food resources, due to flooding. Fishes were sampled monthly from March/2000 to February/2001 (period I) and from March/2003 to February/2004 (period II). The diet of 24 species, showed that aquatic insects were the most exploited by the Ichthyofauna in period I, followed by terrestrial insects and terrestrial plants. In period II, aquatic and terrestrial insects had similar participation in diet, and fish were also important. The trophic niche breadth varied between periods, being lower in period I for most species. The values of diet overlap between pairs of species were similar between periods, and 80% of the pairs had low values (<0,4). The diets of 36 species revealed the generation of nine and eight trophic guilds, in periods I and II, respectively. Considering the species richness, higher values were found in period I, except for the guilds algivorous, terrestrial insectivorous and lepidophages. Numerical abundance showed higher values in period II for all trophic guilds, except the omnivorous, algivorous and herbivorous. The same trend was observed for biomass, except for omnivorous, piscivores and herbivorous, this last one being the only guild that did not occur in period II. The results suggest that i) under conditions of high resource availability, a characteristic of period I, the majority of species opportunistically exploited the most abundant resources, concentrating their diets in a few food items, leading to narrowing of the trophic niche when compared to period II, and ii) the temporal availability of resources was one of the factors responsible for changes in trophic organization of fish fauna in different periods.