Abstract

This study aims to complement existing fish-based assessment approaches by classifying European lampreys and fish species according to their probability of occurrence in six different longitudinal river regions and five types of floodplain water bodies under unimpaired conditions. The main objective was to provide for the first time harmonized occurrence traits for European lampreys and fishes in both longitudinal and lateral dimensions of floodplain river systems in a Fish Region Index (FRI) and Floodplain Fish Index (FFI), respectively.