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Different national assessment concepts impede the harmonization of river quality classifications using macrophytes in Europe. This study describes a procedure to identify similarities between the national methods for ecological quality assessment of Austria, Belgium (Flanders and Wallonia), France, Germany, Great Britain and Poland. Based on an international data set covering three European stream types we identified sites commonly assessed as high status by most methods. A mean index derived from averaging the national assessment results per stream site was then correlated with the abundance of each macrophyte taxon. We defined common macrophyte indicator scores using these correlation coefficients. This enabled the description of type-specific macrophyte communities under near-natural and degraded conditions, and the development of a common metric (mICM) that was correlated with all national methods. The weaker relations of the Flemish and German methods were improved by adjusting national indicator scores of selected macrophyte taxa that deviated from the common indicator scores. The analysis of common high status sites provided mICM reference values. This study offers a general approach to harmonize the national assessment methods for biological elements of any water category. [ABSTRACT FROM AUTHOR]

Diatoms have been routinely used to monitor the ecological status of French rivers. Since 2000, this monitoring has been carried out to comply with the Water Framework Directive. Ecoregions corresponding to the aquatic fauna and flora of rivers were originally defined on the basis of physical descriptors, designated “hydro-ecoregions” in France. Since, they have been simplified into diato-ecoregions for diatoms. In this study, data sets for benthic diatoms from rivers in north-eastern France were used to identify four main groups of diatom assemblages. The first such assemblage is found in small rivers with crystalline geologies in mountainous massifs with neutral to slightly acidic pH. The second assemblage occurs in small rivers flowing on limestone in lowland regions with an alkaline pH. The third corresponds to the assemblage found in large rivers in limestone lowland regions, and the fourth in highly mineralized rivers with high levels of chloride. Within each of these main assemblages, several communities have been characterized corresponding to different levels of pollution: from pristine to highly polluted. Multivariate analysis showed that the underlying geology was the main factor structuring the diatom assemblages, followed by the pollution level. River size had little impact on diatoms. Statistical tests showed that diato-ecoregions provided little information about diatom assemblages in the studied region, whereas there was a close correlation between diatoms and hydro-ecoregions. Nevertheless, these hydro-ecoregions did not account for the diatom assemblages in the highly mineralized rivers. These ecoregions could be further improved by merging the hydro-ecoregions of the crystalline mountainous massifs, all of which shared the same diatom assemblages. [ABSTRACT FROM AUTHOR]

Macroinvertebrate assemblages of large alluvial streams are poorly documented. This study identified the physical characteristics affecting the macroinvertebrates community distribution in a large alluvial river devoid of major anthropogenic impacts. It was oriented towards the influence of the characteristics of the physical habitat (velocity, depth, grain-size classes of mineral substrates, macrophytes) on macroinvertebrates (richness, density, body size, feeding habits), with particular attention to the pollution-sensitive taxa. The study was carried out in June during a period of hydrological stability. The effects of water velocity, depth and substrates on taxa were evaluated with multivariate analyses. Mineral substrates were most abundant while macrophytes accounted for only 3% of sampled habitat. Invertebrates that were present were those characteristics of the transition zone between upper and middle life reaches. Among the 63 taxa sampled, 14 were abundant. In relation to the characteristics of the physical environment, the macroinvertebrate assemblages were discriminated by substrate, velocity, and depth. Habitat exploitation, however, appeared complex. The highest community richness, EPT richness, and density were found in various substrates where the velocity ranged between 30 and 120 cm s−1, depths ranged from 16 to 50 cm. The most pollution-sensitive taxa preferred riffle habitats with velocities >70 cm s−1 and substrate >64 mm. This suggest that rapid bioassessment programmes should be carried out in the mineral substrates of the geomorphological unit riffles where richness is high and density sufficient to represent the macroinvertebrate community, including pollution-sensitive taxa. [ABSTRACT FROM AUTHOR]

Myriophyllum alterniflorum D.C. (Haloragaceae) was studied in the acidic to neutral rivers Vienne and Gartempe (Limousin region, France). Two complementary levels of organisation were evaluated to determine their usefulness for pollution assessment: morphological traits of river populations, and eco-physiological responses to ammonium enrichment in indoor experiments. Inter-node length, stem diameter and leaf length were measured and their ratio calculated for 100 selected plants collected in 20 homogeneous areas. Using multidimensional analysis, their ecological significance for trophic assessment was demonstrated: stem diameter was linked to conductivity, and leaf length/stem diameter ratio to phosphates. Nitrate reductase activity was measured in three populations (upstream, median and downstream populations) after experimental enrichment with ammonium. Ammonium enrichment decreased activity starting at very low concentrations. However, inhibition levels depended on tested populations, with upstream populations being less sensitive due to natural ammonium content in water. The differences could be explained by an eco-adaptation to the trophic level of water. The relationships between the two levels of organisation are discussed. These results could help to distinguish different ecotypes using Myriophyllum alterniflorum. [ABSTRACT FROM AUTHOR]

The aim of our study was to assess the water quality of the upper Moselle river by using biological indices. Simultaneous physico-chemical surveys were also undertaken from May 1999 to April 2000. Twelve sampling sites were selected in order to provide a wide range of potential pollution. Chemical analysis did not reveal any major problem of pollution. However a lower water quality resulting from domestic pollution was established for some sampling sites. A biological monitoring combining both macroinvertebrates and macrophytes was performed. Biological indices based on plant community structure and macrophyte composition were not pertinent tools, whereas simple indices based on taxonomic richness of particular groups of macroinvertebrates were strongly correlated with several chemical parameters, showing that such simple biological variables should represent powerful indicators of ecosystem degradation. [ABSTRACT FROM AUTHOR]

From their introduction in the beginning of the 19th century in the Lez river at Montpellier, the American Ludwigia have, progressively, colonized the whole of France. In spite of their real nuisance for natural habitats, these ornamental hydrophytes are still for sale. The management of these invasive species requires their precise identification, but this appears to be extremely complex. A morphological and cytogenetic study allowed to confirm the presence of two different taxa in France, and the absence of hybrids in the mixed zones that were monitored. The diploids (2 n = 16) correspond to L. peploides subsp. montevidensis (Spreng.) Raven, and the decaploids (2 n = 80) to L. grandiflora subsp. hexapetala (Hook. & Arn.) Nesom & Kartesz. The diploids colonize especially the Mediterranean region (except the Southeastern part), while the polyploids predominate throughout the other regions. Both taxa exhibit an intense vegetative growth, however they have a distinct breeding system: the self-compatible diploids were always found very fructiferous, whereas the self-incompatible polyploids were often observed as sterile. The breeding system difference could explain the substitution of L. grandiflora (first wave of invasion in the 19th century) by L. peploides, in the 20th century, in the southern part of France. [ABSTRACT FROM AUTHOR]

Few studies have dealt so far with the macrophytic communities inhabiting the small Mediterranean rivers in South-East France. In order to fill this gap, it was proposed to assess the effects of natural and anthropic disturbances on the biodiversity in the lowland River Huveaune (South-East France). The Mediterranean climate in this region results in strong seasonal variations in the hydrological regime: there is a long dry period and sudden episodes of flooding occur, which greatly affect the plant community dynamics. The River Huveaune is severely polluted by organic matter. Two stations were set up, one in an upstream reference sector and the other in a downstream polluted sector. The standard sampling area of 100 m2 was divided into plots 4 m2 in size, some of which included part of the river and part of a bank. In addition, plant inventories were drawn up over distances of 50 and 100 m. Seventeen sampling campaigns were carried out from April 2002 to October 2003, resulting in the first systematic list of macrophyte species occurring in small Mediterranean rivers in South-Eastern France. The great variability of the hydrological factors involved leads to considerable spatial and temporal variations in the biodiversity. The upstream station was found to be less severely disturbed and to show a wider range of macrophytes than the downstream station: bryophytes predominate upstream and phanerogams and macroalgae, downstream. The Macrophyte Biological Index for River (IBMR) was tested and found to be a valid means of water quality assessment in small Mediterranean rivers. [ABSTRACT FROM AUTHOR]

Epilithic diatoms of mountain rivers from the upper Segre catchment (Oriental Pyrenees) were studied in 1998, during three different seasons: March, July and September. Four rivers, the river Segre and its three most important tributaries, Duran, Molina and Querol, were sampled in upstream and downstream stretches. The diatom communities were comparable in all upstream stretches of these mountain rivers draining siliceous substrates. Dominant taxa were Achnanthidium subatomus, Diatoma mesodon, Encyonema cf. minutum, E. silesiacum, Fragilaria arcus, F. capucina, Gomphonema calcifugum, G. pumilum, Meridion circulare and Nitzschia pura. Changes in water quality in the downstream stretches lead to the appearance of pollution tolerant taxa, such as Eolimna minima, Gomphoneis minuta, Navicula gregaria, and Nitzschia inconspicua. As a result, the values obtained with the diatom water quality indices (IPS Specific Polluosensitivity Index, CEE and IBD Biological Diatom Index) decreased. The diatom community composition and the derived water quality values did not change in the upstream stretches over the year. In contrast, significant changes were observed in the downstream stretches with best water␣quality in July, during high flows due to melting snow, and worst values in September, during low␣discharge. The diatom indices, especially the IPS, showed a good performance in these mountain rivers. [ABSTRACT FROM AUTHOR]

Changes in the macroinvertebrate community were investigated over 10 months at four sites along a 19 km salinity gradient (0.21–2.60 g l−1) in a sixth-order stream, the Meurthe River, northeastern France. Abiotic characteristics other than salinity were similar between the sites. Macroinvertebrate taxonomic richness decreased by 30% downstream of the 1.4 g l−1 sites while diversity, evenness or total abundance of taxa did not change along the gradient. In terms of functioning, a slight change in relative abundances of invertebrate feeding groups followed the salinity gradient. Eight invertebrate assemblages occurred within specific salinity distributions were identified. The exotics Gammarus tigrinus, Dreissena polymorpha, Corbicula fluminalis and Corophium curvispinum, were more abundant at the highest salinity site. These results suggest that rising salinity concentrations drastically affect the species composition, including favouring exotic species. [ABSTRACT FROM AUTHOR]

The River Durance and its main tributary, the Verdon, are both highly regulated rivers flowing in south-eastern France. The course of both rivers is interrupted by a series of reservoirs with quite different geographical, morphometric, climatic, hydrodynamic and chemical characteristics. The planktonic diatom Asterionella formosa Hassall, which has undesirable cyclic effects from the water management point of view, was studied in this complex of reservoirs located in the Mediterranean region. The results indicate that only the monomictic calcareous reservoirs show a bimodal pattern of Asterionella formosa abundance. The population dynamics of this algal species was found to depend on both the morphometric features and the hydraulic mode of management (retention time) used at each reservoir, as well as on the physical (temperature, suspended matter) and chemical (nitrogen, silica, calcium) characteristics of the water. [ABSTRACT FROM AUTHOR]

Using the distribution patterns of benthic insects (198 species) and fishes ( 29 species) from 11 tributaries and the main channel of the Doubs River drainage basin (French Jura), the authors have tried to establish whether there is an organization of species into discrete, identifiable communities. Principal Component Analysis (PCA) was used to identify whether a continuum existed, and also used to select 50 least-disturbed sites, which were used to define a theoretical watercourse. The density classes of each species were projected on this longitudinal gradient and each species response was characterised by two typological traits: its typological preferendum (tp) and its typological amplitude (ta), thus creating a synthesis of ecological characteristics. In the typological index given in the appendix, the 210 species which form a biological templet are listed in alphabetical order with their tp and ta values. These typological species traits are useful contributions to a database for running waters biomonitoring. [ABSTRACT FROM AUTHOR]

Examines the influence of benthic and hyporheic processes in nutrient fluxes in streams of Rhône River, France. Changes in total suspended matter (TSM) and biodegradable dissolved organic carbon (DOC); Increase in TSM and DOC fluxes due to higher surface velocity; Influence of riffle sediments on the self-purification of rivers.

Evaluates the relationships between mesohabitat heterogeneity and benthic macroinvertebrate in determining the biological integrity of running waters in France. Dominion of a particular taxa in the community; Characteristics of the mesohabitat sampled; Influence of the mosaic heterogeneity on the ecological traits of the invertebrate.

Focuses on studies regarding the use of oligochete communities for assessment of ecotoxocological risk in fine sediment of rivers and canals of Artois-Picardie water basin in France. Analysis of co-inertia of these oligochaete species; Importance of biological data index in the study.

Focuses on the role of aquatic macrophyte communities sequence as an indicator of eutrophication and acidification levels in weakly mineralized streams in north-eastern France. Development of several groups of these microphyte communities in mineralized downstream; Definition of these groups; Characteristics of upstream and downstream zonation corresponding to macrophyte sequence.

Examines the effect of sediment quality of benthic macroinvertebrate communities in streams in the north of France. Environmental impact of intensive industrialization in the region; Characteristics of the benthic macroinvertebrate communities; Information on metal contents of sediments from the different study sites.