Spatial and temporal variation of Odonata larvae associated with macrophytes in two floodplain lakes from the upper Paraná River, Brazil

Abstract

Samples of aquatic macrophytes were collected on Guaraná (Eichhornia azurea) and Patos (E. crassipes and E. azurea) Lakes from March 1992 to February 1993. On Guaraná Lake the highest density and diversity were registered during the high water phase with dominance of Telebasis and Acanthagrion, while on Patos Lake, highest density and diversity were observed during the low water phase. The dominant taxa on Patos Lake were Telebasis, Acanthagrion, Neoneura (?),Coryphaeschna adnexa, Miathyria, Diastatops intensa and Erythemis. DCA and ANOVA differentiated Patos Lake mainly, because of the high abundance of C. adnexa, Miathyria, D. intensa and Erythemis which may be due to morphology of E. crassipes that shelters larger number of invertebrates. Water level variation of rivers influenced concentration of dissolved oxygen and pH. This variation was related the monthly fluctuation of larvae density. Difference between lakes shown in DCA analysis was chiefly due to variation of Odonata density.