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Improvement and spatial extension of the European Fish Index

Final Report Summary - EFI+ (Improvement and spatial extension of the European Fish Index)

Water management in the European Union is mainly regulated by the Water Framework Directive (WFD), which requires standardised assessment of the ecological status of rivers based on fish assemblages. Assessment methods were recently developed in some European countries, however most national regulations are either under construction or not fully compatible with the WFD. Moreover, the existing European Fish Index (EFI) does not accurately represent the conditions of large floodplain rivers, nor of the southern and Mediterranean countries.

Therefore, the aim of EFI+ project was to improve EFI in terms of existing spatial and river specific limitations in order to produce a more accurate pan-European guide. The specific project objectives were to:
1. evaluate the applicability of the existing EFI and apply necessary improvements in the regions that are not accurately represented;
2. extend the implementation of EFI to large floodplain rivers;
3. analyse relationships between hydromorphological pressures and fish assemblages so as to increase EFI accuracy.

An additional goal was to develop a user-friendly software for the calculation of the updated EFI. The project was structured in seven distinct, yet interrelated work packages (WPs) which undertook scientific and dissemination activities.

A common database was collated during EFI+ and statistical models were developed based on selected, undisturbed calibration sites. The database contents included fish information from existing field samples, environmental descriptors which were identified via literature review and human pressure data. Particular variables were selected to account for Mediterranean streams and large floodplains. Moreover, information on different pressure groups was collected at a national level in the participating countries.

The prediction of a theoretical metric value at any given site was therefore feasible through the application of statistical modelling. The metrics with optimal model performance and response to human pressures were included in the formulation of the EFI index, which was calculated as the mean of the selected variables. The finalised proposal consisted of two alternative indices, depending on fish assemblages, which were composed by two metrics. The implementation of EFI+ innovative approach resulted in the revision of the fish requirements’ classification system which had been developed as part of the preceding FAME project.

A web-based, freely accessible software was also provided to assist the calculation of the updated EFI. The index and software were tested in ongoing national and international monitoring programmes and evaluated during end-user workshops. The proposed method performed satisfactorily in most cases and allowed for a direct comparison between different countries’ results without the need for calibration or homogenisation. Nevertheless, observed drawbacks and limitations are yet to be resolved by future research efforts.