Trends in planktonic copepod diversity in reservoirs and lotic stretches in a large river basin in South America

Copepod assemblages were analysed across La Plata River basin, the second largest in South America. High values of species richness and Shannon-Wiener diversity were found in the lower Parana River, the main and largest river of the basin, and in eutrophic reservoirs located in the upper basin. The species richness was negatively correlated with turbidity, probably because of the negative impact on filtration rates in calanoids. There was a trend of decreasing richness correlated with high water flow in reservoirs with short water-retention time (