How does the Taquari River influence in the cladoceran assemblages in three oxbow lakes?

Ea Panarelli,Cn Borges,Am Güntzel

doi:10.1590/s1519-69842013000400006

Abstract

This study examined the cladoceran assemblages in three oxbow lakes of the Taquari River floodplain, near the transition between the plateau and the plain. We sought to answer the following questions: does the Taquari River function as a geographical barrier or dispersal corridor for Cladocera? Can different degrees of connection induce different structures in the assemblages in each lake? Cladocerans and limnological variables were sampled every other month for one year. Forty-one species were recorded, four of which were common to all the lakes. Our results indicated that the different degrees of connection between the river and the oxbow lakes favoured environmental heterogeneity and diversification in the cladoceran assemblages. The greatest dissimilarity between the two lakes connected with the river indicates that in this case the river functions better as a barrier than a dispersal corridor.

Highlights

River flood pulses are known to drive ecological processes in the adjacent floodplain, providing conditions for the establishment of complex environmental heterogeneity
Few studies have contributed to the records of cladoceran species in the Pantanal, among them, only Guntzel et al (2010) has registered cladocerans in the Taquari River floodplain, in the same lakes dealt with in this study, but they only analysed the local diversity for each one of the lakes
Studies focusing the patches dynamics for cladocerans, such as the studies conducted by Cottenie and De Meester (2003), Cottenie et al (2003) and Declerck et al (2011), are rare in Brazilian landscapes, but they are necessary to understand the diversity of cladocerans in systems of the Pantanal

Summary

Introduction

River flood pulses are known to drive ecological processes in the adjacent floodplain, providing conditions for the establishment of complex environmental heterogeneity. In view of the importance of floodplains for the maintenance of biodiversity, and the considerable importance of microcrustaceans at the base of aquatic trophic relationships, it is surprising that so little is known about this group in one of the largest floodplain systems of the world, the Pantanal. Few studies have contributed to the records of cladoceran species in the Pantanal, among them, only Guntzel et al (2010) has registered cladocerans in the Taquari River floodplain, in the same lakes dealt with in this study, but they only analysed the local diversity for each one of the lakes. Studies focusing the patches dynamics for cladocerans, such as the studies conducted by Cottenie and De Meester (2003), Cottenie et al (2003) and Declerck et al (2011), are rare in Brazilian landscapes, but they are necessary to understand the diversity of cladocerans in systems of the Pantanal

Methods

Results

Conclusion