O efeito de diferentes morfometrias das lagoas conectadas sobre a assembleia de Oligochaeta (Annelida) em uma planície de inundação neotropical.

Abstract

The Parana River, located in the enclosures of Porto Rico, the flood pulse is affected by dams, which alter the hydrologic regime of the floodplain connectivity and relationships. However, in areas of permanent connectivity that transfer can often occur due to changes in water level. The input and output of water in connected floodplain lakes act as a factor of disturbance, which substantially modify the stability of aquatic communities. Samples were collected quarterly in 2010 in 16 different connected floodplain lakes of the floodplain of the Paraná River. We used cross section from one to another shore, including the central region. At each point four samples were taken, three for biological samples and one sedimentological, using the handle modified Petersen type background. Among the abiotic variables only daily disturbance correlated with richness (r = 0.26) and density (r = 0.36) For a better understanding of the attributes of the floodplain lakes were categorized as Absent, Low, Moderate and High according to the index obtained propensity to disorder. The higher average density values was found in category absent with a mean of 170 (ind/m2), followed by moderate category mean of 115 (ind/m2). The richness followed the same pattern with the highest average for the category Absent (5.7 sp) followed by the moderate (6 sp). In the majority the floodplain lakes the species Aulodrilus pigueti had shown dominance. The connected floodplain lakes responded differently to disturbance according to their morphology both of its channels and their own. By categorizing the floodplain lakes according to their propensity to disorder, we found that the greatest richness lies in floodplain lakes where the disorder is Moderate.