Protection of aquatic environments. Vulnerability and functional sensitivity of fish communities

Abstract

The European Water Framework Directive (WFD, 2000/60/CE) requires from all Member States to set up monitoring and evaluation of ecological quality, with the aim of preserving and restoring the quality of aquatic environments. Diagnostics of the ecological state are thus regularly operated to identify the water bodies on which restoration measures should be initiated to reach a "good" ecological status. However, the current indices only provide a partial view of the functional changes induced by human disturbances. New approaches in functional ecology, aiming at describing the processes underlying biodiversity and ecosystems functioning, are now opening up new perspectives in the field of ecological diagnosis. These functional indices can already be used to detect changes in the functional structure of communities in response to environmental changes or anthropogenic disturbances. For example, functional redundancy is one of the criteria assessing the functional sensitivity of communities to species loss. It thus provides a quantitative measure of the potential impact of diversity decline on the ecosystem functioning. In addition to the usual criteria, the integration of such indices can provide a valuable resource for defining management plans or for prioritizing sites that should be protected against environmental disturbances, by focusing on ecosystem processes.