Testate Amoeba (Rhizopoda) Diversity in Plankton of the Upper Paraná River floodplain, Brazil

Abstract

In this study we examine the influence of environmental variability on the α and β diversity of testate amoeba assemblages from plankton samples. The samples were collected in the littoral and pelagic zones of the rivers and lagoons of the Parana River floodplain, over one hydrological cycle. Seventy-three species were identified. Alpha diversity was similar in both lagoons and rivers. Although the relationship between α diversity and water level was significant, it was not consistent for all environments, i.e. the pelagic and littoral zones of rivers and lagoons. Temporal β diversity was low and unrelated to environmental stability. Despite the high connectivity among floodplain environments and the suggested homogenizing effect of the flood pulse, spatial β diversity was high, mainly between rivers and lagoons. Also, testate amoeba species composition seems to be more predictable than local species richness.