Measuring redundancy in data from pollution impact studies

Time and money could be save and better invested on environmental monitoring and assessment programs if redundant elements in biological communities were identified. Either aggregation or species into higher taxonomic groupings or selection of indicator taxa are known procedures to eliminate redundancy in large faunal data sets. One further step, the analysis of data without reference to a taxonomic scale, is proposed here. A nondestructive method to just count burrows on sediment surfaces proved adequately suitable to relate faunal responses to water dissolved-oxygen deficiencies along a severely polluted estuary. Consequently, not only taxonomic activities but also the classical destructive approaches separating biota from sediments could be deemed redundant when applied to this case study. Finally, we obtained an extensive benchmark of the situation before the impact is mitigated through the implementation of a sewerage plan promoted by the local water authority. This will serve to: (1) measure the potential recovery of defaunated sediments and (2) evaluate the efficacy of the vast engineering civil work in abating pollution in the near future.