Évaluation de l'état de santé écologique des hydrosystèmes par l'utilisation des traits biologiques

Abstract

Benthic macroinvertebrates are of common use in bioindication. But global indices are not able to diagnose actual causes of damaging. The aim of this study is to integrate recent developments linking biological strategies of animals (reproduction, life duration, feeding habits, respiration) with environmental disturbance. This methodology has been applied to the Chalaronne river, a water body receiving effluents from a waste water treatment plant. Biocenotic analysis, based on abundances of taxa, allows discrimination of upstream from downstream stations since 17.9% of the variability is dedicated to it. Functional analysis, based on biological traits, gives a better discrimination of stations, since the value is equal to 23.1%. This study shows that functional structure observed upstream is characteristic of resilience. On the contrary, functional structure observed downstream is characteristic of resistance. A functional approach is interesting for two reasons: first as a mean to discriminate stations efficiently, and secondly it is promising in study of biological functionalities of ecosystems.