AIM: Aquatic environments of semi-arid regions are subject to changes in water quality and volume due to short and irregular rain seasons. Consequently, zooplankton composition changes in association to fluctuations in the trophic degree. To comprehend these processes, this study analyzed the influence of nutrient concentrations (N and P) on the population dynamics of three species of Cladocera - Moina minuta, Ceriodaphnia cornuta, and Diapahnosoma spinulosum - from the Taperoá II Dam, Paraíba, Brazil; METHODS: Animals were experimentally submitted to different nutrient concentrations as a means to reproduce specific trophic conditions from natural environments. Zooplankton densities were evaluated once every three days, with food (i.e. algal cultures) being supplied in alternate days. To compare population growth, an ANOVA was performed, followed by Tukey's HSD post-hoc test; RESULTS: The population growth of the three species differed significantly both among species and among treatments. Moina minuta populations showed higher growth rates under higher nutrient concentrations, whereas Ceriodaphnia cornuta growed more efficiently in intermediate concentrations, and Diaphanosoma spinulosum showed a better development in low nutrient concentrations; CONCLUSIONS: The results from the experimental approach, presented here, are similar to what is observed in the field, based on previous studies carried out in the Taperoá II Dam. Therefore, these results suggest that the hydrological cycle seems to be the major determinant of zooplankton population dynamics in aquatic semi-arid environments
Cladocera; semi-arid; nutrient; trophic state
