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SUMMARY1 -The study of large-scale pressure-impact relationships involves questions of hierarchy and scales. Answers to these questions will help managers define priorities for action to achieve the 'good ecological status' required by the Water Framework Directive (WFD).The main objectives of our study were 1) to establish the relative impact of pressures that degrade ecological status, especially those caused by agriculture and urbanization, 2) to identify regional patterns in these pressure-impact relationships and 3) to evaluate the relative weight of the pressures acting at the basin and riparian corridor scales, and the possible buffering effect of riparian areas.2 -We developed large-scale models linking invertebrate indices of ecological quality to river basin and riparian land cover in France, Slovakia, Estonia and UK. Invertebrate indices, transformed to Ecological Quality Ratios (EQR), were taken from national monitoring networks. We based the models on Partial Least Squares (PLS) regressions at national and a hydro-ecoregion (HER) scales. The HERs provided a framework for grouping data in terms of natural river features and human activities.3 -The different national methods provided consistent results that indicated the hierarchy of pressures impacting river invertebrates at the European scale. The most salient result was that artificial land cover (e.g. urban and industrial sites) in the river basin represented the pressure with the most negative impact on invertebrate indices, in all countries and regions.Author-produced version of the final draft post-refeering, the original publication is available at Freshwater Biology, 55: 1465-1482. doi: 10.1111/j. 1365-2427.2010.02443.x 4 -The impact of agricultural land cover was more variable. Arable land had a smaller impact than urban areas, and it was even insignificant in some models. The impact of vineyards depended on the natural geographical context. The effect of pastures seemed to be related to the intensity of the livestock they carried. These results supported the concept of regional pathologies for river ecosystems, as land use and anthropogenic influences are closely linked to physical landscape features. The proportion of arable land in the river basin appeared to be a weak predictor of agricultural impacts by itself; the type of cultivation and intensity as well as the proximity to the river must be taken into account.5 -At the riparian corridor scale, the negative impact of artificial areas or arable land and the positive effects of forests and pastures were demonstrated in many regions. The protective effect of riparian forests against mixed agricultural and urban pressures was demonstrated in three regions in France. Riparian corridors appear to be manageable areas, and these results strongly support the idea of including their restoration in priority actions for achieving good ecological status.

The Water Framework Directive (WFD) requires intercalibration to be performed to ensure that ecological status, as defined by the boundary values of national biological assessment systems, is consistent with the definitions outlined in the WFD and comparable between Member States (MS). This article describes an intercalibration of 17 national river macro-invertebrate assessment methods from the Central and Baltic regions of Europe. We explore the hypothesis that intercalibration should be successful if ratios of the observed biota to that expected in reference condition are used to compare assessments of different national assessment systems. National boundaries expressed as ecological quality ratios (EQRs) were converted to values of a common multimetric for the purpose of comparison. Twelve MS for the High/Good boundary and nine MS for the Good/ Moderate boundary (and four MS who subsequently harmonised their boundaries) were within ±0.05 EQR units of the intercalibration boundaries and were deemed to be of comparable ecological standard. The use of a reference-based approach was deemed to be successful given that all the critical pre-requisites for intercalibration were satisfied. The boundaries derived from this intercalibration represent the first common interpretation of the ecological status of rivers based on macro-invertebrate assessment methods across Europe.

We investigated the relationships between different environmental variables and the spatial distribution patterns of the stoneloach (Barbatula barbatula) at the stream system, the stream site, and the mesohabitat (riffle/pool) scales in south-western France. Stoneloach occurred at 240 sites (out of 554 sampling sites), chiefly close to the source, in areas at low elevation and with weak slopes. Population density at a site was primarily influenced by physical conditions. Stream width was positively related to the probability of presence of stoneloach within the stream system, but negatively related to local density. These results indicate that stoneloaches can occur in a wide range of streams, but they are less abundant in wide rivers, probably because of lower habitat heterogeneity. Slope was negatively correlated to both fish presence at the regional scale and local density, suggesting that stoneloach's swimming performance were weak under greater erosive forces. These results suggested that the distribution of populations and the density of stoneloach were governed by the suitability of physical habitat. Multi-scale studies of factors influencing a species' distribution allow to integrate patterns observed at different scales, and enhance our understanding of interactions between animals and their environment. The use of few pertinent variables in successful final models could reduce the effort and cost of data collection for water management applications.

Les modèles biologiques constituent un élément fondamental de la méthode des microhabitats pour l'évaluation de là capacité d'accueil potentielle des cours d'eau vis-à-vis des organismes aquatiques. Avec l'importance croissante de la problématique «habitat» dans les études d'impact est apparue la nécessité de disposer d'outils informatiques performants pour la réalisation des calculs complexes et fastidieux qui en découlent. ProCURVE est un logiciel entièrement dédié à la construction de courbes de preferenda et de profils écologiques pour les organismes aquatiques. D élabore ces modèles biologiques en accompagnant l'utilisateur dans une démarche analytique logique et rigoureuse. Le logiciel permet une gestion aisée des données. La souplesse de la base de données relationnelles lui confère de nombreuses possibilités d'analyses linéaires ou transversales. Son ouverture sur les bases de données externes permet d'envisager le traitement de données déjà disponibles dans la bibliographie. Les variables écologiques utilisées communément sont fournies par défaut mais l'utilisateur a la possibilité de les configurer selon ses besoins. Les résultats générés sont visualisés directement, us peuvent être sauvegardés sous forme graphique ou exportés au format des principaux tableurs pour un traitement complémentaire.ProCURVE : software to calculate habitat preferences of aquatic organisms Keywords : software, biological models, microhabitats, ecological profiles, habitat preferences.Biological models are a major element of the Instream Flow Incremental Methodology for habitat simulation of aquatic organisms in streams. Complex and tedious calculations are required for the growing importance of the «habitat» set of problems in impact studies. This situation emphasizes the need of powerful data-processing tools to process this kind of data. ProCURVE software is a entirely dedicated to the construction of preference curves and microhabitat profiles for the aquatic organisms. It works out these biological models by leading the user in a logical and rigorous analytical process. The software allows an easy management of the data. The flexibility of the relational database confers many possibilities of linear or transverse analyses. Its connection to external databases allows for processing of data already available in the bibliography. Ecological variables commonly used are provided by default but may also be configured by the user. Results produced are directly displayed and can be stored in graphic form or be exported in spreadsheat format for complementary processing.