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The MEDiterranean Pbkp_rediction and Classification System (MEDPACS): An implementation of the RIVPACS/AUSRIVAS pbkp_redictive approach for assessing Mediterranean aquatic macroinvertebrate communities

Abstract:

In Spain, a national project known as GUADALMED, focusing on Mediterranean streams, has been carried out from 1998 to 2005 to implement the European water framework directive (WFD) requirements. One of the main objectives of the second phase of the project (2002-2005) was to develop a pbkp_redictive system for the Spanish Mediterranean aquatic macroinvertebrate communities. A combined-season (spring, summer, and autumn) pbkp_redictive model was developed by using the latest improvements on the selection of best pbkp_redictor variables. Overall model performance measures were used to select the best discriminant function (DF) models, and also to evaluate their biases and precision. The final pbkp_redictive model was based on the best five DF models. Each one of these models involved eight environmental variables. Final observed (O), expected (E), and O/E values for the number of macroinvertebrate families (NFAM) and two biotic indices (IBMWP and IASPT) were calculated by averaging their values, previously weighted by the quality of each DF model. Regression analyses among the final O and E values for the calibration dataset showed a high proximity to the ideal theoretical model, where the final E values explained 73-84% of the variation present in the macroinvertebrate communities of the Spanish Mediterranean watercourses. The ANOVA performed among the reference (calibration and validation) and test datasets showed clear differences for the O/E values. Finally, the assessments carried out by the pbkp_redictive model were sensitive to anthropogenic pressure present in the study area and allowed the definition of five ecological status classes according to the WFD requirements. © 2008 Springer Science+Business Media B.V.