||The European Fish Index is a site-specific method,
thus predicting reference conditions on the site level. In contrast,
the spatially based methods define reference conditions on a river-type
level. Within the FAME project the spatially based approach was initially
applied on the ecoregional and in a later stage also on the European
A standardized procedure was agreed, comprising the following steps:
Due to data availability (sufficient number of reference sites for
the analyses of fish types and sufficient number of data for different
human pressure levels), the spatially based approach was applied to
11 ecoregions (Iberian Peninsula, Pyrenees, Alps, Western Highland,
Central Highlands, Western Plains, Central Plains, Baltic Province,
Great Britain, Borealic Uplands, Fenno-Scandian Shield). For 6 further
ecoregions the number of data in FIDES was too low for statistical
analyses. Within the analysed ecoregions, 60 river types were identified.
For 44 types, specific metric sets demonstrating a statistically proved
correlation between the fish fauna and human pressures were identified.
- Definition of a fish-based typology (= biotic typology)
- Linking biotic and abiotic typology by identifying abiotic factors
and thresholds structuring fish assemblages
- Screening of potential metrics for each river type (= metrics
supposed to respond to human pressures)
- Selection of candidate metrics for each river type (= metrics
proved to respond to human pressures)
- Selection of the final metrics for each river type (tests of
sensitivity to human pressures, redundancy tests)
- Establishment of a type-specific multi-metric index
- Assignment of 5 classes for the ecological status.
For 16 river types the number of data for different degradation levels
was too low for analyses. In a subsequent step the spatially based
approach was applied on the European scale. Altogether, 15 European
fish-based river types were defined based on the 60 ecoregional types.
Type-specific methods could have been developed for 13 river types.
Further details about the statistical tests and the type-specific
assessment methods can be found in the reports
about the spatially based approach.