CHARACTERIZATION OF THE BIOTIC (MACROPHYTES AND MACROINVERTEBRATES) AND ABIOTIC FACTORS OF PANTANAL PONDS IN THE MIRANDA RIVER FLOODPLAIN

Abstract

The Pantanal has an exuberant biodiversity that is constantly regulated by the dynamics of the climate and by the flood pulses. The objective of this work was to characterize and evaluate the biotic (macrophytes and macroinvertebrates) and abiotic factors (pH, temperature, dissolved oxygen, conductivity, total dissolved solids, water turbidity, chlorophyll a and pheophytin-a) of Pantanal ponds depending on the dry or rainy season. Therefore, five ponds with different characteristics were analyzed and five samples of water were collected during the dry and rainy season. For sampling of the macrophytes and collection of the macroinvertebrates we used hand nets (area of 0,09m2, opening of 5000 μm). This was done in order to observe seasonal difference in pH, chlorophyll-a and pheophytin-a and spatial differences between dissolved oxygen, electrical conductivity, turbidity, chlorophyll a and pheophytin-a was observed. The aquatic macrophyte Eichornia azurea ( Commelinales, Ponteridaceae) showed high dominance and relative vegetation cover in at least three ponds, which was also related to higher values of macroinvertebrate biomass. On the other hand, the ponds that presented low dominance or absence of E. azurea presented high diversity of aquatic macrophytes. However, these intrinsic biological characteristics of the ponds altogether with the abiotic parameters demonstrated that there are distinct patterns in the dynamics of these ecosystems during the drought and flood regimes.