Spatial and seasonal variation of zooplankton in reservoirs of the Cantareira system, Brazil

Abstract

This study examined the spatial and seasonal variation of zooplanktonic communities and their relationship to the physical, chemical and biological properties of water in five reservoirs (Jaguari, Jacareí, Cachoeira, Atibainha e Paiva Castro) of the Cantareira system. Sampling was performed in May/June and November/December 2013 at 19 sites. To verify similarity of zooplankton attributes, we applied a two-way similarity analysis and a non-metric multidimensional scaling. Relationship between biological and environmental descriptors was examined by Pearson correlation. A total of 35 taxa was identified. Rotifers were predominant in terms of species richness and juvenile copepods followed by Bosmina freyi were the most abundant. Overall, the sites showed mesotrophic conditions, with the exception of the Jaguari reservoir, which was considered eutrophic. Based on the analysis, spatial and seasonal variations and correspondence between environmental indicators and densities were observed. Reservoir morphometry, water retention time, ecological interactions and water quality might explain the observed trend.