Importance of lateral lagoons for the ichthyofauna in a large tropical reservoir
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Data
2011-11-01
Autores
Ferrareze, M. [UNESP]
Nogueira, M. G. [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Instituto Internacional de Ecologia
Resumo
O objetivo deste estudo foi analisar a composição e os atributos ecológicos das assembleias de peixes de pequeno porte em quatro lagoas e no canal principal do reservatório de Rosana, no rio Paranapanema (SE, Brasil). Os trabalhos de campo foram realizados em setembro e novembro de 2004 e janeiro, março, maio e agosto de 2005. em cada coleta foram realizados cinco arrastos manuais junto aos bancos de macrófitas, utilizando uma rede de arrasto (1,5 × 5 m; 0,3 cm entre nós). Foram coletados 42 espécies e 3.424 indivíduos, totalizando 2.186 g de biomassa. A ordem Characiformes foi dominante, especialmente nas lagoas com menor conectividade com o rio. O principal táxon (Índice de Importância) foi Hemigrammus marginatus. Altos valores de riqueza, abundância, biomassa, diversidade e menor comprimento médio dos indivíduos foram observados nas lagoas, especialmente durante o período chuvoso. A análise de correspondência canônica mostrou haver segregação entre algumas espécies. Os resultados corroboram as hipóteses de que as lagoas marginais têm um importante papel ecológico no ciclo de vida dos juvenis e das espécies de pequeno porte e demonstra como a conectividade rio/lagoa é importante para a manutenção dessas assembléias.
This study aimed to analyse the composition and the ecological attributes of small-sized fish assemblages in four lagoons and in the main channel of Rosana Reservoir (SE Brazil). Fieldwork was carried out in September and November/2004 and January, March, May and August/2005. In each sampling station and period five manual throws were performed towards aquatic macrophyte stands, using a hand net (1.5 × 5 m; 0.3 cm of mesh size). The ichthyofauna collected was represented by 42 species, totalizing 3,424 individuals, 2,186 g in weight. The order Characiformes was dominant, mainly in the lagoons with low connectivity with the river. The main taxon (Importance Index) was Hemigrammus marginatus. Higher richness, abundance, biomass, diversity and lower individual mean length were observed in the lagoons, especially during the rainy period. Spatial segregation of some species was showed by the canonical correspondence analysis indicating the habitat complexity. The results validate the hypotheses that lateral lagoons have a prominent ecological role in the life cycle of juveniles and small fish and demonstrate how the connectivity river/lagoons may be important for assemblages maintenance.
This study aimed to analyse the composition and the ecological attributes of small-sized fish assemblages in four lagoons and in the main channel of Rosana Reservoir (SE Brazil). Fieldwork was carried out in September and November/2004 and January, March, May and August/2005. In each sampling station and period five manual throws were performed towards aquatic macrophyte stands, using a hand net (1.5 × 5 m; 0.3 cm of mesh size). The ichthyofauna collected was represented by 42 species, totalizing 3,424 individuals, 2,186 g in weight. The order Characiformes was dominant, mainly in the lagoons with low connectivity with the river. The main taxon (Importance Index) was Hemigrammus marginatus. Higher richness, abundance, biomass, diversity and lower individual mean length were observed in the lagoons, especially during the rainy period. Spatial segregation of some species was showed by the canonical correspondence analysis indicating the habitat complexity. The results validate the hypotheses that lateral lagoons have a prominent ecological role in the life cycle of juveniles and small fish and demonstrate how the connectivity river/lagoons may be important for assemblages maintenance.
Descrição
Palavras-chave
peixes de pequeno porte, reservatório de Rosana, rio Paranapanema, variáveis limnológicas, small fish, juveniles, Rosana Reservoir, Paranapanema River, limnological variables
Como citar
Brazilian Journal of Biology. Instituto Internacional de Ecologia, v. 71, n. 4, p. 807-820, 2011.