Relación entre los atributos de ensambles pleustónicos y la complejidad de hábitat generada por macrófitas en el río Paraná Medio

Abstract

The habitat complexity generated by macrophytes favours biota diversity and productivity. However, little is known in floodplain wetlands of the Paraná River. Our objective was to evaluate the relationship between pleuston attributes and habitat complexity generated by macrophytes. Samples were collected in six floodplain wetlands. Submerged plant biomass, richness and the fractal dimension were obtained to determine different measurements of complexity. Invertebrates were identified and classified according to different functional groups. The organisms were counted and their biomass was determined by direct weight or using available factors. Correlation tests between the attributes and habitat complexity were performed. A high diversity, density and biomass of taxa and functional groups were found. Complexity was directly related to richness and density of invertebrates with high affinity to plant substrate (shredders, scrapers, herbivorous) and indirectly to overall and collector density. Macrophytes provide habitat for diverse and abundant macroinvertebrates in the Paraná River. Attributes are related to the complexity of the submerged portions of macrophytes differentially in relation to substrate-affinity of macroinvertebrates. Both, macrophytes and invertebrates participate by drift in local and regional processes, thus supporting floodplain-river system  resilience.