Establishing demographic reference condition procedures for Italian river fish bioindicator

The Water Framework Directive 2000/60/EC (WFD) requires Member States of the European Union (EU) to use a pool bioindicators, that is, Biological Quality Elements (BQEs), including fish species and each State shall, in fact, certify compliance with ecological quality goals WFD. New Italian Index Ecological Fish Communities (NISECI) is WFD-compliant index for analysis BQE river water bodies, both wadable non-wadable, are not (using WFD definitions) heavily modified or artificial. relate conditions found field reference corresponding absence anthropogenic alterations minor alterations. present study defines logical basis on model refinement metrics submetrics NISECI relating biological condition indigenous non-indigenous species. was tested an empirical using data from 284 ichthyological samplings taken basins throughout Italy. In order clean random errors stochastic noise due possible different sampling methods, only collected protocols guarantee adequately homogeneous reliable abundance (overall by size). developed approach provided comparable results watersheds; this allowed standardized robust threshold values demographic parameters NISECI. procedure used, consistent spatially based expert judgement approaches envisaged WFD, improves analytical performance increasing its power resolution applicable every zoogeographic context.