Structure and dynamics of the cyclopoid copepod (Crustacea) assemblage associated with aquatic macrophytes in two lotic environments of the Upper Paraná river basin, Brazil

Abstract

Spatial and temporal variation was analyzed in the composition, diversity, and abundance of cyclopoid copepods associated with Eichhornia azurea (Swartz) Kunth in two lotic environments of the Upper Paraná river basin. Sixteen cyclopoid taxa were identified. There were no differences in the composition of copepod species between environments or hydrological phases. Cyclopoids were generally more abundant during the low water phase. The most abundant species in both environments were Macrocyclops albidus albidus (Jurine) and Microcyclops finitimus Dussart. Densities and some measurements of species richness were in general higher in the Ivinheima River, which has many associated floodplain lakes. This fact suggests the importance of associated lentic environments for patterns of abundance and species richness found in lotic environments. Low values for β diversity of the cyclopoid assemblage in both environments seem to indicate that the littoral region has low temporal heterogeneity