A key issue in the implementation of the Water Framework Directive is the classification of streams and rivers using biologicalquality parameters and type-specific reference conditions. Four groups of stream types were defined in NE Spain on the basisof 152 diatom samples by means of detrended correspondence analysis and classification techniques. Diatom analysis was restrictedto epilithic taxa, and the sites included gradients ranging from near-natural streams to sites with poor ecological quality.The main gradient shows a clear separation of sites in relation to the degree of human influence: polluted streams (mainly locatedin the lowlands) differ from streams in mountainous areas and in the Pyrenees. A second gradient is related to physiographicalfeatures. Headwater streams can be distinguished by their catchment geology. The type-specific diatom taxa for the streamtypes studied were determined by using indicator species analysis (IndVal). The type-specific taxa from near-natural streams arecoincident with the indicator taxa for high ecological status. Human impact reduced the typological heterogeneity of the diatomcommunity composition. Overall, the diatom communities in NE Spain exhibit a regional distribution pattern that closely correspondswith that observed in river systems elsewhere. Physiographical differences are only evident in undisturbed sites, whilenutrient enrichment and other human disturbances may mask the regional differences in the distribution of diatom communities.

The composition and abundance of functional feeding groups of the macroinvertebrate communities were investigated alongthe Chubut River in the Patagonian Precordillera and Plateau, Argentina. Chubut River (>1000 km) is the largest river in the area and the hydrological regime is modified in the lower section by an artificial reservoir (Florentino Ameghino Dam). Quantitative benthic samples were collected at 13 sites in the upper, middle and lower sections of the river basin. Sites were visited four times during 2004 and physicochemical parameters, chlorophyll a and particulate organic matter (POM) were assessed. In terms of relative abundance, collector-gatherers and scrapers/grazers were the predominant groups at most sites. Shredders were not abundant in the upper sites and were practically absent at middle and lower basin sites. Collector filterers that comprised morethan 25 % of abundance at the pre-regulated site were practically absent right below the dam. POM biomass decreased significantly with distance from the source and chlorophyll a showed a marked increase below the reservoir. We conclude that although there was a distinct headwaters fauna in the Chubut River, and sequential downstream changes in species composition, most functional feeding groups (apart from shredders) were represented down the whole length of the river. Finally, the usefulness of biotic indices and metrics in relation with main environmental features of the Chubut River basin is discussed.

A meeting held in Toulouse, France, from 23rd to 25th February 2006 and co-organised by the University Paul Sabatier ToulouseIII & CNRS (France), Pôle Relais Mares et Mouillères de France (France), University of Applied Sciences of WesternSwitzerland (Switzerland), University of Geneva (Switzerland), Pond Conservation (UK), University of Leuven (Belgium).

Ponds are an essential freshwater habitat for plants and animals, and they play a central role in maintaining high regional biodiversity. In addition, ponds have many other functions relating to education, recreation, economy, hydrology, culture and aesthetics. Despite their importance, relatively few resources are invested in pond conservation in Europe. Furthermore, the scientific basis for the management and conservation of ponds is currently weak compared to the information available for other freshwater habitats. Some national environment agencies from countries such as France, the United Kingdom and Switzerland, have recently developed elements of a national strategy for pond conservation. There is now need to strengthen and develop these initiatives and to build a common framework in order to establish a sound scientific basis for pond conservation in Europe. The European Pond Conservation Network (EPCN, www.europeanponds.org) was established at the First European Pond Workshop in Geneva, October 2004. The mission of the Network is to promote awareness, understanding and conservation of ponds in a changing European landscape. Specifically the objectives of the Network are: (1) to exchange information on pond ecology and conservation between researchers, managers and practitioners, (2) to promote understanding of pond ecology by encouraging the development and coordination of fundamental and applied research, (3) to raise the profile of ponds and guide national and supra-national policies for their protection, (4) to promote effective practical pond conservation, and (5) to disseminate information on the importance, attractiveness and conservation of ponds to the people. The "Pond Manifesto" presents the background and the motivations of the EPCN.

The programme LIFE Nature "Conservation and restoration of habitats of the Rhine fringe" (2002-2005) focussed on the assessment of the conservation status of terrestrial and aquatic habitats. Along the Rhine fringe, the degree of connection between waterbodies and the river main channel determined the water flow (surface or phreatic waters, flow velocity) and induced flood disturbances (hydromorphological quality, scouring effect). A new typology based on metrics characterizing the conservation status, was proposed for the upper Rhine floodplain. Seven physical and biological metrics were selected: specific richness, presence or absence of rare, polluto-tolerant and exotic species, species abundance, degree of connection, and trophy level defined by the macrophyte community. Aquatic macrophytes surveys were conducted at 315 sites along the Rhine French fringe. Multiple correspondence analysis and discriminant analysis were used to define metrics scores in a preliminary network of 129 macrophytes surveys stands. Metrics were combined to give a measure of the conservation status of the 315 sites. Five classes of the conservation status have been defined from degraded to excellent status. The mapping of the conservation status was realized to answer the question addressed by the program “Life Nature”. We discuss on the choice of the metrics and their justification in the definition of the conservation status. The method was tested in the fluvial hydrosystem of Ill river, the main tributary of the Rhine river in the Alsace floodplain, and compared to the French trophic index based on macrophytes, IBMR.

A set of 21 ponds was sampled three times for odonate larvae during spring 2002. At the same time 17 environmental variableswere recorded including area, wet phase duration, total nitrogen, total phosphorus, aquatic macrophytes and land use. Atotalof 16 odonate species belonging to Lestidae, Coenagrionidae, Aeshnidae and Libellulidae were recorded, and the total numberof species per pond varied from zero to six. The relationships between species richness, assemblages and environmental variableswere studied by simple and multiple correlation and by Canonical Correspondence Analysis (CCA). The results showed thatpermanent ponds were larger, deeper, had more macrophyte species, had more extensive macrophytes cover and lower concentrationsof nitrogen and phosphorus than temporary ponds. Multiple regression analysis showed that the number of odonate specieswas positively affected firstly by the number of macrophyte species, and then by pond depth. However, pond depth appearedto be interchangeable with several others variables, such as pond area and water duration and negatively correlated withnitrogen concentration, variables which are all linked with the permanent or temporary status of the ponds. CCA analysis indicatedthat odonate species presence was linked with a few environmental variables, showing a tendency of Odonata to avoidponds with higher nitrogen concentrations, with the exception of Lestes barbarus, a species typical of temporary water in centralItaly. At the same time, the majority of species were linked with longer water phase duration and with greater macrophytespecies richness. Acomparison with previous studies, and in particular with those carried out in central Italy, confirmed the positiveinfluence of macrophytes, water duration, and also the negative effect of nutrient load. However, several other variables,in particular land use, shade, presence of fish, which were influential in other studies, were not significant in this study.

An analysis of the morphology and the prey consumed by two carnivorous species of bladderworts (Utricularia gibba and U. sp.2) from a pond (Annie pond) in the heart of the Kaw swamp (French Guiana) has allowed a comparison of the preferential prey of: 1) a single species over two different periods (the end of the rainy season and the beginning of the dry season during an oligotrophic phase); and 2) the two coexistent species within a single period (the beginning of the dry season, during a temporary mesotrophic phase). Among the immediately adjacent planktonic and periphytic animals, and despite their low prevalence relative to smaller organisms such as Gastrotricha and Rotifera, cladocerans and copepods (particularly large individuals) appeared to be strongly predated. The differing organization and size-class distributions of the traps, as well as the extent of epiphytic colonization, had a probable defining effect on the alimentary regime of the two species of Utricularia. These more or less adaptive characteristics allowed the bladderworts to take advantage of the distinct preferences of various potential prey in terms of nutrition behaviour and habitat so to limit the feeding competition between the two sympatric species. The impact of this selective zooplankton predation by bladderworts on the trophic organization and the ecological functions of this pond are also addressed.

Salinity is a serious threat to freshwater ecosystems, particularly those near coastal areas. An increase in salinity producesdrastic changes in community structure of freshwaters, sometimes in an irreversible fashion. Thus, freshwater species must copewith salinity stress in a manner proportional to their degree of tolerance. Bearing this in mind, we studied the acute and chroniceffects of different salinity concentrations in two species of cladocerans: Daphnia magna Straus, a standard test organism, andDaphnia longispina O. F. Müller, an autochthonous species. Salinity experiments were based on successive dilutions of a stocksolution of NaCl in a synthetic medium. The results showed that D. magna is more tolerant than D. longispina, both in acute(EC50 5.9 and 2.9 g/L, respectively) and chronic (EC50 5.0 and 2.2 g/L, correspondingly) exposures. In the chronic exposure,salinity caused a significant reduction in fecundity and a developmental delay (increase in age at first reproduction), as well asa decrease in the growth rate of daphnids. However, these effects were mainly observed at salinity concentrations where mortalityoccurred.

This paper contains a compilation of the average values of 24 geographical, physical, chemical, biological and productivity parameters collected and processed during 12 years of research on 9 freshwaters and salmastricol lakes situated on the Romanian seaside of the Black Sea. The paper emphasizes the discussion of those parameters indicating the current degree of eutrophication of these lakes. It shows that the lakes situated in the southern part of the Romanian seaside (Limanu, Valea Arsa and Hagieni) are the least affected by the process of eutrophication; they are followed by the northern lakes (Razim and Sinoie) which are supplied with the waters of the Danube river, after these have been filtered in the floodable areas of the Danube Delta. The process of eutrophication is found to be stronger in the waters close to the agricultural areas and the urban localities from the Romanian seaside of the Black Sea.

Phytoplankton dynamics and morphological plasticity were studied in an oligo-mesotrophic lake from late spring to earlyautumn in 2004 on a weekly to bi-weekly basis. This study aimed to evaluate the effect of environmental constraints on morphologicalplasticity and size structure of dominant species through the stratified period of the lake. While centric diatoms developedmainly in the epilimnion, Fragilaria crotonensis, Synedra sp. and Synedra acus were very well distributed through thewhole water column, as was the cryptophyte Plagioselmis nannoplanctica. A filamentous cyanobacterium, Planktothrix rubescens,was stratified in the metalimnion throughout the sampling period, while Mougeotia sp. was entrained through the wholewater column during the early autumn. Surface area / volume (S/V) ratios were calculated for the dominant species on each samplingdate. The minimum S/V ratio was found with centric diatoms, while maximal values measured were for Synedra sp. andAsterionella formosa. The S/V ratio of the only dominant cryptophyte, Plagioselmis nannoplanctica was also high; variationswere negatively correlated with NO3-N and PO4-P (-0.62 and -0.61, respectively) and positively correlated with euphotic depth(r=0.57) and temperature (r=0.82). On the other hand, the S/V ratios of Fragilaria crotonensis and Cyclotella ocellata each showedstrong negative correlation with silica concentrations (-0.55 and -0.62, respectively). It is concluded that allometric relationshipsshowed significant differences among species according to depth and season.

Diatoms are good environmental indicators and are often the main component of phytobenthos, one of the key groups of organismsrecommended by the Water Framework Directive (W.F.D.) for the assessment of ecological status of surface waters.Although diatoms are regularly used as indicators in rivers and in lakes, less is known about the benthic diatom communities inwetland systems, especially in Italy. The main aim of the project was to provide a contribution to the knowledge on distribution,composition and structure of benthic diatom communities in wetland systems in Italy. In 2005, we investigated the benthic diatomcommunities and their relationships to water variables of nine ponds and wetlands along the Tyrrhenian coast near Rome.Furthermore, a first application of seven European diatom-based indices on this type of water body was undertaken. A total of225 species and varieties belonging to 54 genera were identified. The Canonical Correspondence Analysis indicated that certainspecies were closely associated with each wetland type and their distribution mainly depended on nutrient and chloride contents:pollution tolerant species (i. e. Luticola goeppertiana, Mayamaea atomus, Navicula subminuscula) in the wetlands connected toriver mouths, halophilous species and also marine littoral species (i. e. Nitzschia elegantula, Amphora coffeaeformis, Achnanthesbrevipes var. intermedia, Epithemia adnata var. porcellus) in the coastal brackish ponds and wetlands, and less eutrophic species(i. e. Achnanthidium minutissimum, A. biasolettianum) in the lowland freshwater wetland. In general, the indices classifiedmost of the studied water bodies as bad, poor and moderate status; few sites were classified into a good class, even for at leastin one sampling occasion. Eutrophication and Pollution Index (EPI-D), Trophic Diatom Index (TDI), Taxa Pollution Tolerant(%PT), Pollution Sensitivity Index (IPS) and Generic Diatom Index (IDG) were significantly correlated to nutrient contents inthe studied wetlands. Our preliminary data set illustrated the potential of the use of these benthic algae as bioindicators in wetlands.

The paper presents a description of the hitherto unknown larva of Drusus nigrescens Meyer-Dür, 1875. Information on the morphological and genetic identification of this species is given, and the most important diagnostic features are illustrated. Its systematic position within the genus Drusus is affirmed and some zoogeographical and ecological notes are added.

Cladocerans are used in a wide range of applications (aquatic toxicology, experimental hydrobiology, and aquaculture). Although known to be successfully cultivated with microalgal food sources, cladoceran demographic parameters tend to be different, depending on the kind of cladoceran and concentration of food supplied. For most species, finding precise instructions on culture conditions and expected outcomes is difficult. The aim of this study was to determine the most favorable feeding conditions for the development of three cladoceran species frequently used as test organisms in aquatic toxicology. For this purpose, Ceriodaphnia dubia, Daphnia pulex, and Simocephalus mixtus were fed three concentrations (6, 12, and 18 mg L-1 dry weight) of the green microalgae Ankistrodesmus convolutus, Pseudokirchneriella subcapitata (formerly Selenastrum capricornutum), and Scenedesmus incrassatulus. Reproduction and survival were evaluated during the entire life cycle. For C. dubia, the P. subcapitata and S. incrassatulus diets produced the best reproductive results. For D. pulex, the best overall results were obtained with S. incrassatulus at 6 mg L-1 and results with P. subcapitata were similar at all concentrations. For S. mixtus fed P. subcapitata, results were similar at all concentrations. With S. incrassatulus, a decrease in longevity and an increase in fecundity occurred as the amount of food increased; the best reproductive response was achieved with the highest (18 mg L-1) concentration. The lowest reproduction and survival in the three cladocerans were recorded with A. convolutus. For the cladoceran species tested, the same microalga produced different reproductive and survival results, depending on the concentration; some of the tested foods did not support adequate cladoceran development, because they were nutritionally deficient, despite the similar conditions used for their production. Feeding and culture conditions here described could be useful for a controlled propagation of these cladocerans.

We studied the influence of lotic and lentic stretches on zooseston flux in the karstic barrage Plitvice Lakes (Croatia). Threesampling stretches were selected: 1) a channel with low inclination; 2) water flow through a deep lake (retention), and 3) a channelwith cascades and sharp inclination. At all sampling points of the three stretches, zooseston reached maximum abundance inSeptember (up to 147.39 ind/m3). Rotifers dominated in both zooseston abundance (58 to 80%) and diversity (66 taxa), followedby crustaceans (23 taxa), predominantly Cladocera and Copepoda. Kruskal-Wallis test suggest statistically significant differencesbetween the lentic and both lotic stretches in the biomass net flux of euplanktonic organisms. The net flux of benthicorganism biomass and changes in the biodiversity index were significantly different between the lentic stretch and lotic stretchwith high inclination. Lotic stretches had a greater influence on the increase of abundance and biomass of benthic and semiplanktonicorganisms than on the decrease of euplanktonic organisms. Principal Components Analysis of the species environmentrelationship explained 66% of the variance by the two first axes, where axis 1 accounted for 39% and axis 2 accounted for27% of the variance. Oligochaets, insect larvae, nematodes and total zooseston were associated with component 1, showing thattheir biomass was negatively correlated with discharge and dissolved oxygen concentration and positively correlated with temperature.Other taxa showed a similar correlation with component 1. Biomass of Cladocera, Copepoda, T. birostris, Polyarthraspp., K. cochlearis and rotifers was associated with component 2, and positively correlated with food resources such as chl-a,POM and DOM. The inference is that zooseston flux through Plitvice Lakes is a function of the hydrological and physiographicalfeatures of the stretches, as well as food resources from the lakes.

Romania has a unique diversity of large branchiopods in Europe, but the present distribution of species is poorly documented.This note is a summary of a survey aimed at a rapid assessment of large branchiopod occurrence and frequency at a landscapelevel. The survey was conducted in ten landscapes, and it lasted from 2004 to 2006, recording fifteen species. Most species(80%) were only found in one or two landscapes, showing large differences in species composition between landscapes andpossibly an underestimation of some species. Four landscapes had a frequency of large branchiopod habitats greater than 30%and together contained all the species found during the survey. Based on the relatively large detection probabilities found duringthis survey we suggest that a country-level distribution database could be done in a short time period (in a few years) even withfew participants. Target areas for further distribution surveys should be the localities described in the published literature, flatlands and middle to large river valleys.

The stability of occurrence, abundance and dominance of fish was compared between two sampling periods, 1963-66 and 2002-04 in two lowland rivers from the Warta/Odra system (Poland): the Widawka and its tributary Grabia (95.8 and 77.3 km long, respectively). The Widawka system has been under strong influence of a brown coal strip mine since the 1970s. Long stretches of the upper Widawka and of its certain tributaries were changed into concrete canals, which receive daily 660 000 m3 of water disposed by the strip mine. The Grabia maintained its natural character. On the basis of the abundance of fish species, the Kohonen artificial neural network almost perfectly separated fish samples collected in 1963-66 from samples collected in 2002-04, which means that: 1) the differences in ichthyofauna between these two sampling periods were more drastic than spatial differences between the severely modified Widawka and the natural Grabia, and 2) in general, ichthyofauna at the most modified sites in 1963-66 was in better condition than at the least modified sites in 2002-04. In 1963-66, the species, roach, gudgeon, bleak and dace composed together 70% of the total fish number, while in 2002-04 the same joint dominance was gained by roach, perch and stone loach. The analysis of temporal changes in the Widawka and Grabia Rivers focused on the following 3 fish groups: (1) Non-psammophilous rheophils (NPR), which are most vulnerable to human-induced modifications, which is why their decline and/or extinction are typical for unbalanced lotic ecosystems. In this study, the total dominance of NPR decreased 5 times; (2) Psammophilous rheophils (stone loach and gudgeon), which often predominate in degraded smaller streams. In this study, the dominance of stone loach increased 3 times and was highest in the most affected stretches of the Widawka River, including those that had been canalised. Gudgeon was often dominant at moderately modified sites of the Widawka; (3) Roach and perch, whose high dominance is typical for disturbed larger rivers, which was supported also in this study by the fact that both species were most dominant in 2002-04. The dominance of roach increased almost twice and was highest in the lower courses of both rivers. A significant increase in abundance was recorded for perch, whose dominance was highest in the canalised section of the Widawka. The described changes were deep enough to influence the hardly sensitive CDI, Simpson and Shannon indices, which indicated a significant increase in dominance and a decrease in diversity of fish assemblages over the last 4 decades.

The colonization and succession of periphytic ciliate communities on the natural (Phragmites australis and Typha Iatifolia) and artificial (glass slides) substrata were studied in 2 shallow lakes (Polesie Lubelskie, Eastern Poland). Sampling was done on a monthly basis from April to November 2003-2004. During each sampling occasion 6 periphton samples were collected from each type of substrata at 3 sites: the land/water contact zone, among emergent macrophytes, and at the emergent macrophytes/open water border. Irrespective of the type of substrate and trophic state, species number and densities of periphytic ciliates reached the highest value in the land/water contact zone and decreased in the direction of the area of emergent macrophytes/open water zone. In land/water contact zone, the biggest factors limiting the ciliate communities were temperature, conductivity, concentrations of total organic carbon and nutrient (Ptot and N-NH4). In turn, in the other 2 zones, the influence of chlorophyll a concentration increased.

Recent publications suggest that in large watersheds a large proportion (20 to 70%) of the net nitrogen input to the aquaticenvironment may be removed during water’s downstream path towards the outlet. In small watersheds there are few to no evaluationsof the importance of in-stream processes in the overall nitrogen budget due in part to the lack of simple and robustmethods for measuring in-stream nitrate uptake. We propose a comparative study for laboratory and field measurements on openmesocosms, 30 cm in diameter. Nitrate uptake was evaluated from the kinetics of disappearance of nitrate in water overlyingundisturbed sediment cores, both in the laboratory and in-situ. Using both laboratory and in-situ mesocosms was an effort todetermine whether the methods were comparable and applicable on a routine basis. Nitrate disappearance kinetics in the laboratoryyielded expected results, which are that nitrate uptake rates are linearly correlated to nitrate concentration in the watercolumn. In such conditions, our results show that the potential for nitrate uptake in streams can be calculated from the mass transfercoefficient. Our comparative study shows that incubations conducted in the laboratory intrinsically limit hyporheic exchanges,associated with small water level fluctuations, which may in fact prevail in the field as the in-situ incubations have shown.In-situ experiments yielded unexpected results, such as the succession of disappearance and gain of nitrate in the mesocosmsthrough time. This was attributed to hyporheic exchanges, both natural and artificially induced by the design of the mesocosms.Both methods should be considered for future nitrate uptake studies as they yield complementary results, provided that somesimple changes are made in the design of in-situ mesocosms.

We studied the status of Crested newt (Triturus cristatus superspecies) ponds in the province of Salzburg during the years 2004and 2005. Historical and current distribution data were collected and compared. In the end of 2004, 51 ponds with Crested newtrecords of which 39 still existed were known in Salzburg. In 2005 we carried out a monitoring of these ponds using a combinationof three survey methods. Presence or absence of adult and larval Crested newts and the number of syntopic amphibian specieswere recorded. Detection probabilities and the effects of seven characteristic pond features on pond occupancy were calculatedfor adult and larval newts separately. We observed a strong decline of ponds occupied by Crested newts with presence of adultsin 22 and presence of larvae in 16 surveyed ponds, respectively. Detection probabilities imply that we detected all ponds occupiedby adults and larvae. Key habitat features for Crested newt presence are low degree of shading for adults and larvae as wellas a high density of submerged vegetation for larvae. Pond size and depth are not significant. Furthermore we recorded a significantlyhigher number of amphibian species in ponds occupied by Crested newts. Our results might aid in the implementationof sustainable measures for a conservation of these critically endangered species in the province of Salzburg.

We studied the morphology of two ‘flesh-eating’ Chydoridae Anchistropus emarginatus Sars, 1862 and Pseudochydorus globosus (Baird, 1830), using populations from Belgium, with particular attention to the structure of the trunk limbs. Both genera belong in subfamily Chydorinae, and both have morphological adaptations with implications for the interpretation of limb morphology in the subfamily. Anchistropus has a large number of specific characters, many of which directly relate to the animal’s habit of feeding on Hydra. In Pseudochydorus globosus, specializations are less numerous. A redescription of both species is offered, with an aim at allowing future comparisons with populations outside the Palaearctic, where cryptic species are expected to occur.