Peixes de pequeno porte associados à macrófitas aquáticas em uma planície de inundação neotropical.

Abstract

We assessed the diel activity (time), horizontal distribution in habitats (space) and diet composition (food) of small body fishes in a shallow lake of the Upper Paraná River floodplain to identify which niche dimension promotes species co-existence. Furthermore, was verified if the diet of the most abundant species varied with seasonal fluctuation of water level and changes of the structure of habitat. In general, there was an overlap of the activity times, use of space and food, and the identical pairs of species along a dimension differed in another one. Although all dimensions were relevant, the trophic dimension was slightly more important in segregating the species. During the low water period the species had well defined diets and during high water, their diets were similar and consume of cladocerans predominated. In vegetated habitats, the diet was more diverse and in the most complex macrophyte (E. azurea roots), this variety was still higher for three of the four species analyzed, suggesting that complex structures are important in furnishing richer sources of food. Our results show the importance of niche complementarity for small body fishes and importance of assessing their diet under different temporal and spatial conditions which promotes changes in the food resource availability.