PROJECT DESCRIPTION
BACKGROUND
In Europe, water policy is currently subjected to considerable changes in line with the recent European Water Framework Directive (WFD - 2000/60/EC), which requires the assessment of their hydro-morphological, chemical and biological characteristics for the restoration and maintenance of "healthy" aquatic ecosystems. Compared to previous policies, the WFD gives strong priority to biological quality goals by introducing measurements of aquatic biota necessary to identify the structural and functional integrity of ecosystems. Furthermore, the WFD introduces river basin management throughout Europe, which could have major impacts on the conservation and restoration of aquatic systems. The ecological quality of an aquatic ecosystem is based on the spatiotemporal integration of the different physical, chemical and biological components. In order to improve the protection, the long term use and the adequate monitoring of the aquatic ecosystems, it is required to identify and take into account some global metrics, complementary to those used in traditional water quality assessment. Among the potential bio-indicators, fish exhibit several characteristics (presence at different levels of the trophic chain, long life, aptitude to integrate environmental alterations occurring at different levels of the aquatic ecosystem, sensitivity to habitat degradation), providing original and complementary information to those already available from other organisms.
OBJECTIVES
This project intends to adapt and standardize to the European ichthyofauna a new index of ecological quality assessment based on the attributes of fish communities (from the concept of IBI - index of biotic integrity - originally developed in the United States). This will enable the evaluation of the global quality, the conservation and restoration of lotic ecosystems in an international river basin (The Meuse). The metrics of this multiparametric index are classified into three major categories : richness and specific composition, trophic composition, fish health and abundance. The methodology developed during this project will be used as a tool for the evaluation of the ecological status of the water bodies, in close conformity with the proposal of the European Commission (Commission Proposal for a Council Directive establishing a Framework for European Community Water Policy - consultation draft of 4/12/96). This objective will be reached through an international collaboration between countries concerned by the matter (France, Belgium and The Netherlands).
RESULTS
The project found both indices (Trisection Methods Index - TMI, Multivariate Method Index - MMI) to be very efficient in discriminating over a gradient of anthropogenic perturbations. They are also both flexible and widely adaptable. The MMI seems to be the more appropriate index for an application to the whole river Meuse basin. Nevertheless, the application of this index requires the selection of reference sites from water quality and, particularly, from habitat quality criteria, with the involvement of appropriate experts and / or application of a well defined widely accepted and standardised index of habitat (which is lacking for the time being). The TMI has overall a good ability in assessing anthropogenic perturbations but tends to underscore systematically the ecological quality of sites and more especially the Flemish sites and large river sites. In view of an international application, the MMI could be recommended, after it is validated in other European river basins, while, the TMI could be used in a regional context. The project reached its objectives through the implementation of the following main tasks: 1. Determination of potential zonation in the whole Meuse River basin, through an analysis of historical and recent data. Testing and standardisation of sampling methodologies used by the different partners during their regional or national programmes, and definition of ecological guilds for autochthonous fish species. 2. Determination of reference systems by prospecting sites without perturbations in the tributaries and the less altered sites in the main channel. 3. Selection of IBI metrics for tributaries and main channel, respectively, and study of the influence of the potential zonation in The Meuse basin. For the main channel, special attention was paid to the identification of specific metrics based on the spatiotemporal variations of the fish communities, in terms of population dynamics and relative abundance of the different cohorts in some target fish species which are good indicators of the quality in large rivers. Multivariate analysis was used to balance the different metrics. 4. Study of IBI spatiotemporal variation and comparison of its sensibility with other physico-chemical and biological indicators. The project found both indices (Trisection Methods Index - TMI, Multivariate Method Index - MMI) to be very efficient in discriminating over a gradient of anthropogenic perturbations. They are also both flexible and widely adaptable. The MMI seems to be the more appropriate index for an application to the whole river Meuse basin. Nevertheless, the application of this index requires the selection of reference sites from water quality and, particularly, from habitat quality criteria, with the involvement of appropriate experts and / or application of a well defined widely accepted and standardised index of habitat (which is lacking for the time being). The TMI has overall a good ability in assessing anthropogenic perturbations but tends to underscore systematically the ecological quality of sites and more especially the Flemish sites and large river sites. In view of an international application, the MMI could be recommended, after it is validated in other European river basins, while, the TMI could be used in a regional context. The project reached its objectives through the implementation of the following main tasks: 1. Determination of potential zonation in the whole Meuse River basin, through an analysis of historical and recent data. Testing and standardisation of sampling methodologies used by the different partners during their regional or national programmes, and definition of ecological guilds for autochthonous fish species. 2. Determination of reference systems by prospecting sites without perturbations in the tributaries and the less altered sites in the main channel. 3. Selection of IBI metrics for tributaries and main channel, respectively, and study of the influence of the potential zonation in The Meuse basin. For the main channel, special attention was paid to the identification of specific metrics based on the spatiotemporal variations of the fish communities, in terms of population dynamics and relative abundance of the different cohorts in some target fish species which are good indicators of the quality in large rivers. Multivariate analysis was used to balance the different metrics. 4. Study of IBI spatiotemporal variation and comparison of its sensibility with other physico-chemical and biological indicators.