CNR-IRSA activities related to INHABIT

Ecological classification and lentic-lotic character in Mediterranean rivers

The scientific hotspots for the definition of the ecological quality of Mediterranean rivers are considered in regard to aquatic invertebrate communities. In this geographical area, rivers are characterized by a high variability of discharge. This variability has a strong influence on both abiotic and biotic processes. In the context of the Italian legislation, methods in use before the WFD (i.e. IBE) were screened to check their potential for assessing the ecological quality of Mediterranean rivers. The main objective of this Quaderno is to quantify the level of influence exerted by the lentic-lotic character of river sites on the evaluation of the biological attributes used in assessing ecological status for the European Water Framework Directive. The results presented here refer to rivers located in the Italian Apennines and Sardinia. The main factors acting on the biological communities were quantified (e.g. physio-chemical parameters, hydromorphology, general degradation). For the purposes of hydromorphological characterization, as required by the WFD, the Southern European version of the River Habitat Survey (RHS), successively named CARAVAGGIO after further improvement, was applied. Multivariate analyses were run to establish major discontinuities in the biological community across stream types and areas, which resulted strongly related to the lentic-lotic character of the sites. The variability of the main abiotic variables and biotic metrics among the groups identified by TWINSPAN, was analyzed. The results clearly show how natural variability, linked to local hydraulic conditions, can be confused with the effect of anthropic stress on invertebrate communities. In general terms, the research emphasizes the need for developing specific assessment systems which fulfil WFD requirements for the evaluation of the ecological quality of Mediterranean rivers.

Quaderno IRSA 122 on Mediterranean rivers (2004) - CLASSIFICAZIONE ECOLOGICA E CARATTERE LENTICO-LOTICO IN FIUMI MEDITERRANEI - Ecological classification and lentic-lotic character in Mediterranean rivers (in Italian)