ABSTRACT
This paper reports on a study involving an estimate of the biomass of rotifers, cladocerans, and cyclopoid and calanoid copepods found in reservoirs in different trophic conditions, comparing and relating numerical density data and pointing out differences between the dry and rainy seasons. In terms of numerical densities, both reservoirs were dominated by rotifers, although cladocerans represented a higher biomass in the oligotrophic environment in both seasons. In the eutrophic environment, higher biomass values were found for cyclopoids during the dry season and for cladocerans during the rainy one. Different biomass patterns were observed relating to both the trophic conditions and the rainy and dry seasons.
Subject(s)
Biomass , Zooplankton/classification , Animals , Brazil , Eutrophication , Fresh Water , Population Dynamics , SeasonsABSTRACT
Este trabalho descreve um estudo sobre a determinação dos valores de biomassa de rotíferos, cladóceros, copépodos calanóides e ciclopóides em represas de diferentes estados tróficos, com o objetivo de comparar e relacionar com dados de densidades numéricas, considerando os períodos chuvoso quente e estiagem frio. Verificou-se que, embora rotíferos tenham dominado numericamente em ambas as represas, em termos de biomassa os cladóceros predominaram no ambiente oligotrófico, em ambos os períodos considerados. No ambiente eutrófico, copépodos ciclopóides predominaram no período estiagem frio, e cladóceros, no chuvoso quente, evidenciando padrões diferenciados de biomassa tanto em relação às condições tróficas quanto aos períodos chuvoso e seco.
Subject(s)
Animals , Biomass , Zooplankton/classification , Brazil , Eutrophication , Fresh Water , Population Dynamics , SeasonsABSTRACT
This paper reports on a study involving an estimate of the biomass of rotifers, cladocerans, and cyclopoid and calanoid copepods found in reservoirs in different trophic conditions, comparing and relating numerical density data and pointing out differences between the dry and rainy seasons. In terms of numerical densities, both reservoirs were dominated by rotifers, although cladocerans represented a higher biomass in the oligotrophic environment in both seasons. In the eutrophic environment, higher biomass values were found for cyclopoids during the dry season and for cladocerans during the rainy one. Different biomass patterns were observed relating to both the trophic conditions and the rainy and dry seasons.
Este trabalho descreve um estudo sobre a determinação dos valores de biomassa de rotíferos, cladóceros, copépodos calanóides e ciclopóides em represas de diferentes estados tróficos, com o objetivo de comparar e relacionar com dados de densidades numéricas, considerando os períodos chuvoso quente e estiagem frio. Verificou-se que, embora rotíferos tenham dominado numericamente em ambas as represas, em termos de biomassa os cladóceros predominaram no ambiente oligotrófico, em ambos os períodos considerados. No ambiente eutrófico, copépodos ciclopóides predominaram no período estiagem frio, e cladóceros, no chuvoso quente, evidenciando padrões diferenciados de biomassa tanto em relação às condições tróficas quanto aos períodos chuvoso e seco.
ABSTRACT
This paper reports on a study involving an estimate of the biomass of rotifers, cladocerans, and cyclopoid and calanoid copepods found in reservoirs in different trophic conditions, comparing and relating numerical density data and pointing out differences between the dry and rainy seasons. In terms of numerical densities, both reservoirs were dominated by rotifers, although cladocerans represented a higher biomass in the oligotrophic environment in both seasons. In the eutrophic environment, higher biomass values were found for cyclopoids during the dry season and for cladocerans during the rainy one. Different biomass patterns were observed relating to both the trophic conditions and the rainy and dry seasons.
Este trabalho descreve um estudo sobre a determinação dos valores de biomassa de rotíferos, cladóceros, copépodos calanóides e ciclopóides em represas de diferentes estados tróficos, com o objetivo de comparar e relacionar com dados de densidades numéricas, considerando os períodos chuvoso quente e estiagem frio. Verificou-se que, embora rotíferos tenham dominado numericamente em ambas as represas, em termos de biomassa os cladóceros predominaram no ambiente oligotrófico, em ambos os períodos considerados. No ambiente eutrófico, copépodos ciclopóides predominaram no período estiagem frio, e cladóceros, no chuvoso quente, evidenciando padrões diferenciados de biomassa tanto em relação às condições tróficas quanto aos períodos chuvoso e seco.
ABSTRACT
OBJECTIVE: To identify and compare the immature Culicidae population and their predators in different breeding places in a public city park. METHODS: The study was carried out in an ecological park situated in the outskirts of the city of São Paulo, Brazil. Four Culicidae breeding places were selected: one semi-permanent, two permanent and one polluted brook. Throughout a year, at monthly intervals, systematic and standardized collections of Culicidae and their predators were undertaken to assess mosquito frequency, and estimate the index of abundance and predatory potential of the associated fauna. RESULTS: A total of 9,065 Culicidae were collected at the four breeding places studied. Twenty-two species or groups were obtained, generally at low frequencies, except for Culex quinquefasciatus, the only species at the polluted breeding place seen highly frequent. This was the most abundant species in this study, followed by others of the Culex genus. CONCLUSIONS: It was found an imbalance in the polluted breeding place as a result of a high concentration of pollutants and absence of predators, which leads to an intense proliferation of only one species. At the other breeding places, there is evidence that the associated fauna promotes a natural biological balance.