Response of stream biotic indicators to pressures and extrapolation of biological status to unmonitored water bodies

Abstract

In order to face the limitations of the monitoring networks to evaluate the ecological status, it was necessary, during the implementation of the Water Framework Directive (WFD) evaluation rules, to be able to rely on reliable and reproducible methods in order to evaluate in a homogeneous way the ecological status of water bodies without biological data. To this end, we have built a corpus of models capable, on the one hand, of prioritizing the impact of the different types of anthropic pressures on the biological indices used in the networks and, on the other hand, of satisfactorily predicting the good status situations determined from the biological indicators. While it is very important to encourage the construction of pressure-impact models based on robust and complete pressure data sets to support the classification of water bodies according to the WFD request, this development should not be considered as an antagonistic approach to the improvement of the monitoring network but rather as a means of providing a general framework to help water policies.