Characterization, Ecological Status and Type-specific Reference Conditions of Surface Water Bodies in Wallonia (Belgium) using Biocenotic Metrics based on Benthic Invertebrate Communities

摘要: The river types in Wallonia (Belgium) were defined according to the system B of European Water Framework Directive (WFD) taking into account obligatory and optional factors synthesized three criteria: 'size', 'slope' 'natural region'. Under hypothesis that benthic invertebrate assemblages would be specialized type, a set 627 faunal samples originating from an 11-year sampling period was tested characterize with assemblages. A multivariate approach led gather 23 seven groups exhibiting similar Using biocenotic metrics based on (e.g., French standard IBGN), type-specific reference conditions ecological status class limits for each 'natural' type group. Ecological potential heavily modified artificial (i.e., man-made canals) types. An 'ecological status' evaluation strategy therefore developed applied southern - more natural part Wallonia, where many sites available. In northern 'Loess region') no high quality site available, expert judgement took larger definition limits, addition calculations. Two independent distribution gradients taxa resulted ordination: first 'saprobity axis', as taxa-sensitivity organic contamination increasing 'very resistant' (mainly located 'sensitive' sensitive' (from belonging Condroz, Famenne, Arden Jurassic regions) second axis characterizing Meuse-specific assemblage, gathering exotic species typical limnophilous large rivers. monitoring management this study i.e., groups, related represents proposal integrated assessment biological elements implementation WFD Wallonia. For 2000-2002 involving 349 different sites, element 'benthic fauna' way classified 'high 31.5% 'good below 37% sites. best 100% 'high' 'good' status) found 'Arden's xenotrophic brooks strong slope' 'large rivers medium slope'. worst