Effects of natural banks of free-floating plants on zooplankton community in a shallow subtropical lake in Southern Brazil

• Published in: Brazilian archives of biology and technology Vol. 54; no. 4; pp. 745 - 754
• Main Authors: Gazulha, Vanessa, Montú, Mônica, Marques, David da Motta, Bonecker, Claúdia Costa
• Format: Journal Article
• Language: English
• Published: Instituto de Tecnologia do Paraná (Tecpar) 01-08-2011
• Subjects: macrophytes; refuge; spatial distribution; tropical zooplankton
• ISSN: 1516-8913; 1516-8913; 1678-4324
• DOI: 10.1590/S1516-89132011000400014

The aim of this study was to test the effects of natural free-floating plants on zooplankton distribution in a shallow subtropical lake. First, the hypothesis that free-floating plants have an effect on physico-chemicals, leading to a decrease on nutrient availability and influencing the phytoplankton biomass and zooplankton community was tested. Second, the hypothesis that free-floating plants act as a refuge for zooplankton was tested. Three microhabitats were selected: free-floating plants, littoral area and open water. Results demonstrated that the effects of different microhabitats on phytoplankton biomass and physico-chemicals were not significant, indicating a weak influence of the plants. Zooplankton densities were higher in free-floating plants and littoral area, although the effect of microhabitats was weak for most of the predominant genera. The absence of free-floating plant effects on phytoplankton and physico-chemicals showed that it was not a factor influencing the microcrustacean distribution in the microhabitats. Low differences in densities of zooplankton among microhabitats and low abundance of large-bodied cladocerans led to reject the hypothesis that free-floating plants act as a refuge for zooplankton.