Relationship between micro-invertebrates and macrophytes in a wetland : Laguna Ibera (Corrientes, Argentina). Implications for water quality monitoring

From November 2000 to September 2001, eight points in the Iberá lagoon were sampled bimonthly. At each point, pH, temperature and dissolved oxygen were measured and invertebrates were collected from the water around macrophytes by mean of a net of 180 mu m pore size. Four biotic indices were calculated and compared, given similar trends. The total number of taxa shows to be a good and simple indicator of water quality. Averaging indices across points we obtained a good positive correlation between indices and temperature. In this ecosystem, multi-habitat sampling must be used in order to obtain a good estimation of ecological integrity. The total number of taxa can be used for water quality assessment.