The hydraulic management of the Barra Bonita reservoir (SP, Brazil) as a factor influencing the temporal succession of its fish community
Carregando...
Data
2007-08-01
Autores
Petesse, ML. [UNESP]
Petrere Jr., M. [UNESP]
Spigolon, RJ.
Título da Revista
ISSN da Revista
Título de Volume
Editor
Instituto Internacional de Ecologia
Resumo
A sucessão temporal das comunidades de peixes permite avaliar o estado do ambiente e a capacidade de adaptação das espécies às perturbações. Com este propósito, a comunidade de peixes da represa de Barra Bonita foi amostrada em duas épocas do ano (seca e chuvosa) em três zonas diferentes do reservatório: fluvial, transição e lêntica. A lista das espécies foi comparada com outras quatro, referentes a coletas anteriores, visando detectar as variações ocorridas na composição ictiofaunística da represa, ao longo dos últimos 15 anos. Para avaliar a adaptação da comunidade atual à variabilidade ambiental, a estrutura trófica e reprodutiva foi analisada junto com a gestão hidráulica da represa. O número total de registros por autores varia entre 23 e 39, num total registrado de 68 espécies. Destas, 27 podem ser consideradas constantes, 14 acessórias e 27 acidentais. As principais diferenças observadas estão nas famílias: Anostomidae, Loricariidae e Characidae. em relação à gestão hidráulica, os resultados mostram uma comunidade estabilizada e adaptada às flutuações ambientais, dominada por espécies de pequeno porte, amplo espectro alimentar e alta compensação reprodutiva (r-estrategistas). A sobreposição dos ciclos biológicos das espécies mais abundantes com as fases de enchente e esvaziamento da represa indica o período de setembro a março-abril como crítico para o sucesso reprodutivo. Estes resultados, interpretados no contexto do processo de velhice do ambiente, indicam que a represa de Barra Bonita está entrando numa fase de transição entre a de colonização e velhice.
The temporal succession of fish communities allows evaluating the environmental conditions and the adaptation capacity of the fish species to anthropogenic stress in reservoirs. The fish community at Barra Bonita reservoir was sampled in two different periods of the year (dry and rainy) and in three different areas of the reservoir (fluvial, transition, and lentic). The species list was compared to another four lists, trying to detect the transformations of the fish community for the last 15 years. In order to evaluate the adaptation of the present fish community to the hydraulic management of reservoir, the trophic and reproductive structures were studied. Temporal succession analysis shows little change in fish richness of the communities. The number of fish species varies between 23 and 39 for a total of 68 registered species. From this, 27 can be considered constant, 14 accessory and 27 accidental; the main differences observed were for Anostomidae, Loricariidae and Characidae families. In relation to the hydraulic management, we found a fish community stabilized and adapted to environmental stress. This is characterized by the dominance of small-sized fish species of opportunistic diet and high reproductive compensation (r-strategists). The overlap of biological cycles of the most abundant species with the reservoir level fluctuations points to the period from September to March-April as critical for reproductive success and only the species with partial reproductive strategy or parental care are best succeeded. These results, interpreted in the context of the reservoir aging process, indicate that Barra Bonita reservoir is entering a transition phase, between the colonization and aging stages.
The temporal succession of fish communities allows evaluating the environmental conditions and the adaptation capacity of the fish species to anthropogenic stress in reservoirs. The fish community at Barra Bonita reservoir was sampled in two different periods of the year (dry and rainy) and in three different areas of the reservoir (fluvial, transition, and lentic). The species list was compared to another four lists, trying to detect the transformations of the fish community for the last 15 years. In order to evaluate the adaptation of the present fish community to the hydraulic management of reservoir, the trophic and reproductive structures were studied. Temporal succession analysis shows little change in fish richness of the communities. The number of fish species varies between 23 and 39 for a total of 68 registered species. From this, 27 can be considered constant, 14 accessory and 27 accidental; the main differences observed were for Anostomidae, Loricariidae and Characidae families. In relation to the hydraulic management, we found a fish community stabilized and adapted to environmental stress. This is characterized by the dominance of small-sized fish species of opportunistic diet and high reproductive compensation (r-strategists). The overlap of biological cycles of the most abundant species with the reservoir level fluctuations points to the period from September to March-April as critical for reproductive success and only the species with partial reproductive strategy or parental care are best succeeded. These results, interpreted in the context of the reservoir aging process, indicate that Barra Bonita reservoir is entering a transition phase, between the colonization and aging stages.
Descrição
Palavras-chave
represa de Barra Bonita, ictiofauna, transformação da comunidade, estrutura trófica e reprodutiva, Barra Bonita reservoir, fish assemblage, temporal succession, trophic and reproductive structure
Como citar
Brazilian Journal of Biology. Instituto Internacional de Ecologia, v. 67, n. 3, p. 433-445, 2007.