A partir d'échantillons de crevettes capturées par pêche à l'électricité de 1977 à 1980, les principales caractéristiques de la population d'Atyaephyra desmaresti de la Meuse ont été décrites et analysées. Ainsi, l'abondance de ce crustacé diminue au cours des années étudiées ; le sex-ratio femelles/mâles moyen est de 1,6. C'est une espèce univoltine, le recrutement a lieu en été. Des données concernant la durée de vie, les croissances en longueur (Longueurs totales maximales des femelles et des mâles : 36 et 29 mm), et en poids (Poids maxima atteints par les femelles et les mâles : 250 et 137 mg) ont été analysées. La période de reproduction s'étend sur 4 mois : de mai à août. La taille minimale des femelles à maturité est de 22 mm. La relation entre la fécondité et la taille de la crevette est de type linéaire. Enfin, le régime alimentaire de cette espèce est essentiellement détritivore.

Obtaining an adequate and representative sample is a continuing challenge of community ecology. The present study focuseson what sample area represents adequately the structural composition of the caddisfly fauna of a riffle, at a given sampling occasion.Sixty-two Surber samples were collected from a riffle in a second-order reach of the Bernecei Stream (BörzsönyMountains, Hungary). This data set was used to estimate sample representativeness at different sample sizes (from 1 to 31 Surbersamples, 0.09 m2 - 2.79 m2) generated a re-sampling procedure. Sample representativeness was measured with mean JaccardCoefficient and Bray-Curtis Index between samples for species presence-absence data and abundance data, respectively. Wefound that a sample size of 2.25 m2 represented well (mean similarity 0.998) the species composition of the caddisfly fauna ifrare species were excluded from the analysis. In contrast, sample representativeness of species composition proved to be relativelylow (0.719) if rare species were included in the analysis. Curves of sample representativeness based on both raw-, or transformedabundance data were less sensitive to the presence of rare species and showed lower representativeness than samplerepresentativeness based on presence/absence data.

Des récoltes d'exuvies nymphales de Chironomides obtenues par dérive dans 14 stations réparties sur les 178 km amont d'une rivière de basse montagne du Massif Central français ont permis de recenser 109 espèces. En ajoutant les 17 espèces récoltées en vol par Gagneur (1976), 126 espèces ont été identifiées ce qui représente 31 % du total des espèces d'invertébrés du benthos.

Avec 72 espèces, la sous-famille des Orthocladiinae est particulièrement bien représentée notamment par les 3 genres les plus fréquents et les plus diversifiés : Eukiefferiella (14 espèces), Cricotopus (16 espèces) et Orthocladius (9 espèces). La sous-famille des Buchonomyiinae et l'espèce Buchonomyia thienemanni Fitt. sont citées pour la première fois en France. L'écologie de plusieurs espèces est précisée. La succession des espèces apparaît comme un phénomène continu ; on peut cependant reconnaître 4 groupements avec leur biocénoses respectives, compatibles avec le système de zonation de Illies et Botosaneanu (1963).

29 stations lotiques ont été prospectées en Vallée d'Ossau (Pyrénées-Atlantiques) entre 450 et 2 150 m d'altitude et 30 espèces d'Ephéméroptères récoltées. Deux analyses factorielles des correspondances — dont l'une tenant compte des paramètres du milieu — ainsi qu'une classification ascendante hiérarchique ont été effectuées. Les 5 groupements d'espèces mis en évidence correspondent : I aux ruisseaux très froids de haute altitude, II aux torrents de moyenne montagne et aux ruisseaux de haute altitude à températures estivales élevées, II a aux rivières de piémont, III a aux ruisseaux assez lents et à forte teneur en calcium, III b aux ruisseaux à faible courant et à fond vaseux riche en macrophytes.Le régime thermique et la vitesse du courant apparaissent nettement comme les principaux facteurs de répartition enmontagne. L'altitude , la surface du bassin-versant, le numéro d'ordre du cours d'eau, le régime hydraulique et les caractéristiques physico-chimiques jouent aussi un rôle important. Les préférences écologiques des principales espèces sont discutées.

The influence of the sediment grain size and the trophic status of the reservoirs on the composition, richness and biomass of Oligochaeta community was tested. Samples were taken from the littoral and profundal zones of 30 neotropical reservoirs from six different watersheds during two hydrological periods (dry and rainy seasons). The sample units were ordinated, with principal component analyses, according to differences in the sediment grain size, sample depth and dissolved oxygen. The results of a multiple response permutation procedure (MRPP) analysis revealed significant differences in species composition between littoral and profundal zones, trophic status (oligotrophic, mesotrophic and eutrophic) and different watersheds. The environment–species relationship was tested using redundancy analyses. In order to test which environmental variables, either granulometric or limnological, influenced the Oligochaeta community variability we used a partitioning procedure of inertia. Local variations, including reservoir zone and trophic status, were primarily influenced by differences in sediment type and depth. Significant differences in the total biomass between zones, trophic status, watershed and hydrological period were also demonstrated by a Kruskal–Wallis or Mann–Whitney test. The most prevalent taxa were the cosmopolitan tubificids Bothrioneurum sp. and Branchiura sowerbyi, and the naidids Dero (Dero) digitata and Pristina breviseta, which are dependent on periphyton for food. Higher biomass values were recorded in mesotrophic reservoirs, due to increased nutrient availability and adequate dissolved oxygen supply. Our results indicate that the Oligochaete community structure is directly influenced by local environmental variation in neotropical reservoirs; and that the sediment grain size is the most important factor in determining the Oligochaete community structure.

Les auteurs présentent la première liste des Diptères Chironomidae signalés jusqu'en 1990 de France continentale et de Corse. Il a été tenu compte des synonymies anciennes et récentes. Des corrections et des additifs sont apportés aux listes régionales publiées antérieurement. La présentation choisie permet de faire le lien avec la partie consacrée aux Chironomidés dans la Limnofauna Europaea éditée par Illies (1978). Avec 598 espèces recensées, le territoire français s'avère être l'un des plus riches d'Europe en Diptères Chironomidés.

Strong oscillations in the rotifer community are frequently observed in eutrophic lakes, where rotifers are important components of the zooplankton community. Manipulations with increased level of fertilizers, presence or absence of fish, abundances of competitors (cladocerans) and predators (Asplanchna) were performed in polyethylene-enclosures. The experiments provided evidence for pure eutrophication effects (e.g. elevated pH) and predation from Asplanchna as the main controlling factors. The influence from potential competitors such as Daphnia and Bosmina was found to be of less importance, at least during these short-term experiments.

Research in the phytoplankton community has become an important part of the overall water-quality monitoring. However, to date studies in small rivers and streams were still scarce and sampling methods were also diverse and not as well developed as in lakes or large rivers. We investigated whether two sampling protocols collected different phytoplankton assemblages within a lowland catchment and, consequently, influenced the outcome of bio-assessment. Data collected from 77 sites by plankton net (PLNET) collection and sedimentation (SEDIM) protocols were analyzed. Median Bray–Curtis (BC) similarity between phytoplankton assemblages generated by the two protocols was 48.5% (range: 7.5–82.0%), and sites with the lowest BC similarities tended to have lower chlorophyll a (Chla), water temperature (WT), total suspended solid (TSS) and volatile suspended solid (VSS), but higher channel width and water depth, than other sites with higher BC similarities. Reduced total algal density and biomass, but higher species richness, were observed by the PLNET protocol. However, overall phytoplankton assemblages generated by the two protocols were similar, as indicated by dominant species (paired t-test, P>0.05) and non-metric multidimensional scaling (NMDS) ordination. Nevertheless, from the phytoplankton-based bio-assessment point of view, PLNET protocol was a better method compared with SEDIM protocol because algal data collected by PLNET protocol had higher relationship with environmental variables as indicated by ‘Correlation Index’ (CoI), Cumulative_R2 and canonical correspondence analysis (CCA).

Bioassays have been carried out with the green alga Scenedesmus crassus in order to elaborate a technique for evaluating phosphorus bioavailability. This was achieved by the use of three parameters related to the uptake of this element (yield, growth rate and intracellular concentration of phosphorus). Judging from the results obtained, the most reliable parameter is the yield. This parameter is well correlated with intracellular concentration of phosphorus which has the advantage of being measured after 10 days. Coupling these two parameters enables a sharper analysis of a wider array of samples and supplements the data provided.

Dès la concentration initiale de 125 µg Cu/l, le sulfate de cuivre en eau dure affecte la capacité des larves d'Hydropsyche à construire un filet. La première irrégularité apparente est le nombre élevé d'interruptions des fils. A concentration plus élevée, le nombre de mailles par filet diminue.

Une anomalie typique de l'action toxique du cuivre est le dépôt de fils sous la forme d'amas de soie. La symétrie et la régularité des mailles dans la zone de capture n'est que faiblement affectée par le cuivre. Ceci contraste avec les effets d'un carbamate, insecticide étudié antérieurement.

La localisation première de l'action du cuivre paraît être la glande à soie et non le système nerveux comme cela est le cas avec l'insecticide précité.

Les résultats obtenus en laboratoire confirment les observations de terrain. Les concentrations affectant sévèrement la construction des filets empêchent les larves de se développer dans la nature. Le test Hydropsyche n'exige que de courtes périodes de temps et un équipement simple ; il fournit cependant une information sur des effets à long terme.

All English populations of Arctic charr are found in the Lake District (northwest England). There are at least four races of charr in Windermere, the largest natural lake in England, with the north and south basins of the lake each containing two distinct races that spawn in autumn and spring respectively. Three methods have been used to estimate levels of the charr stocks ; namely gill-netting each November (1939-1991) for autumn spawners in the north basin, anglers' catches from both basins (1966-1991), echo-survey data from both basins (July 1989 - December 1991). An increase in gill-net catches from 1945 to 1965 was associated with a cull of larger pike, Esox lucius L. ; since 1965, catches have fluctuated around a high mean level. There was good, if not excellent, agreement between the anglers' catches and the gill-net catches. The ratio of anglers' catches in the north and south basins showed that catches have been relatively low in the south basin since 1984. Although there has also been an increase in brown trout, Salmo trutta L., taken by the charr anglers since 1984 in the south basin, this increase was not responsible for the lower charr catches. When estimates of fish densities with an echo sounder were restricted to fish > 20 cm and depths down to 20 m, this being roughly the stock available to charr anglers, there was good agreement between monthly estimates and anglers' catches, especially in the north basin. The echo-sounder data confirmed the higher numbers in the north basin, and lower numbers in winter in both basins. The three different methods therefore provided comparable data on the fluctuations in levels of charr stocks in Windermere. Possible reasons for these fluctuations are discussed briefly.

Les auteurs étudient au laboratoire et à diverses températures quelques caractéristiques de la production de femelles mictiques. La durée du développement juvénile (Dj) de femelles mictiques non fécondées ne montre pas de variabilité intraspécifique. Les durées de développement embryonnaire (De) et juvénile diffèrent chez les deux types de femelles, amictiques et mictiques. Toutefois, elles varient en sens contraire de sorte que le temps de génération (De + Dj) est peu variable (mécanisme decompensation). Dans une gamme de températures normales pour l'espèce (10-20 °C), le taux net de reproduction, Ro, ne varie pas et se situe à environ 30 œufs par femelle amictique ou mictique. La production de femelles mictiques (dont les œufs subissent une méïose) est contrôlée par la température et la densité de population. La température semble le facteur primordial dans la mixis chez cette espèce vivant dans un environnement fluctuant. La production de ce type de femelles et des œufs de durée qu'elles pondent après fécondation, est supérieure à température élevée (20 > 14 > 10 °C). Du fait d'une proportion élevée de femelles mictiques, le taux de croissance de population à 14 °C estinférieur à celui obtenu à 10 °C. Outre là production de propagules (propagation de l'espèce dans l'espace et le temps), la mixis contribue à la régulation de la croissance des populations aux températures chaudes.

Zooplankton samples were collected over a 21-month period in five floodplain lakes of the Orinoco River in orderto establish zooplankton species composition, abundance patterns, and biomass and their relationships with the patterns of inundations and lake morphometry. 60 rotifer taxa were identified. This group was generally more abundant thancopepods and cladocerans (mean : 73,4 % of total zooplankton). Common and abundant rotifer species included K. americana, K. cochlearis, B. mirus, B. gessneri, P. vulgaris and F. longiseta. Copepods were dominated by nauplii (mean : 73,8 % of total copepod stages). Cladocerans were scarce and dominated by M. minuta, C. cornuta and D. spinulosum.Most frequent and abundant zooplankton species were euplanktonic with a dominance of filter feeders and microphagous detritivores. Mean zooplankton density in all lakes ranged from 340 ind./l to 3 486 ind./l. Biomass ranged from 71,1 µg.l (dw) to 432,8 µg/l. Rotifers accounted for 64,7 % of the total mean zooplankton biomass in three lakes whilecopepods accounted for 57,8 % of the biomass in two lakes. Both density and biomass were markedly seasonal withhighest mean values at low waters. Mean density in the lakes was 100 times higher than in the Orinoco main stem. Lakeswith highest variabilities in surface area and water depths showed highest zooplankton densities. The type of connection (direct or indirect) established between the lakes and the major source of the water also seemed important to interpret the productivity of floodplain lakes.

In Buenos Aires province, the river Samborombón, which is typical of the plain, was sampled monthly during 1986-1987 inresearch carried out both on its physico-chemicalcharacteristics and the communities present - plankton, phytobenthos, zoobenthos -. In this paper the structure and function of phytoplankton and benthic algal communities in the different sections of the river are compared. Both communities have definite limits as their components are not shared and show different strategies. Likewise, the environmental conditions along the river are variable, leading to differences in the planktonic and benthic algae at the locations studied.

The relative importance of biotic and abiotic variables on the Common Kingfisher Alcedo atthis breeding distribution in northern Iberian rivers was quantified through surveys completed in 2007. Eight rivers were surveyed for “positive” and “negative” (control) breeding territories (PBT and NBT, respectively). PBT (N=9) were 3-km river sections with breeding pairs; NBT (N=8) were 3-km river sections close to PBT, where no pairs were found, with apparently similar features to the PBT and one or more cut banks suitable for nesting. Stepwise discriminant analysis (SDA) correctly classified 94.1% of territories and revealed PBT was associated with higher oxygen concentrations, a lower maximum depth and lower proportion of rockfills. Causes and consequences of these findings are discussed.

For the first time, a faunistic list of the Chironomidae fauna of Greece is presented along with its ecological distribution. Chironomidae larvae and pupal exuviae were collected from 61 locations in mainland Greece during 2006–2008. 76 taxa (genera to species) were recorded. The genera Potthastia, Brillia, Euorthocladius, Synorthocladius, Tvetenia and Xenochironomus are recorded for the first time from Greece. Furthermore, 12 species are new for Greece and five are new for mainland Greece. Chironomidae collected from running waters were analysed with ordination techniques. The results revealed that Chironomidae assemblages were distinguished into three ecoregions with distinct climatic, geological and hydrochemical features. Running waters in Northwestern Greece were generally dominated by species tolerant to water acidification. Chironomids typical of eastern uplands preferred relatively slow current and soft bottom sediments. Assemblages of the southern Peloponnese Peninsula were represented by species of relatively fast flowing, warm streams. However, these are only preliminary results and many more data are needed to justify this ecological distinction of Chironomidae assemblages. This is the first study contributing to the knowledge of a rather neglected insect group of the Greek fauna. It is expected that more species remain to be identified and recorded and future works will contribute to this initial faunal list.

Two species of superfamily Cytheracea from Skadar Valley (Montenegro), are presented in this paper. Leptocythere pseudoproboscidea n.sp., collected in a spring is very close to Leptocythere proboscidea Klie, 1939, an endemic species of the Ohrid Lake. Paralimnocythere karamani (Petkovski, 1960) occurred in two localities : river and spring. Until now, this species was considered endemic in the Ohrid-Prespa region. Its known distribution is non extended westwards and its presence in Skadar Valley confirms exchanges between faunas of Ohrid and Skadar drainage areas.

L'étude d'abondantes récoltes de larves d'Elmis aenea, E. maugetii et E. coiffaiti nous a permis de confirmer l'existence de six stades larvaires chez ces espèces. Le nombre des poils ramifiés latéraux portés par les lames paratergales des huit premiers segments abdominaux permet de différencier aisément ces six stades.

Les larves d'Elmis coiffaiti peuvent être identifiées dès le premier stade par leur ornementation tergale. Celles d'E. aenea et d'E. maugetii ne peuvent être distinguées l'une de l'autre qu'à partir du stade IV. Le plus ou moins grand développement de renflements parasagittaux sur les tergites abdominaux est le caractère spécifique le plus constant. Il existe également des différences dans la forme du neuvième segment abdominal, déjà indiquées par Bertrand [1939], pour E. coiffaiti (sub nom. Helmis fossulata), et dans la répartition des mamelons.

Toutes ces différences sont néanmoins assez réduites, ce qui confirme l'étroite parenté des trois formes. Adultes et larves vivent ensemble toute l'année dans le même habitat et, au point de vue pratique, il est préférable d'effectuer des récoltes suffisamment abondantes et de déterminer d'abord les mâles, par l'examen des édéages [Steffan 1958, 1961, Berthélemy 1962], puis les femelles, par comparaison de leur morphologie externe avec celle des mâles, et enfin les larves, en commençant par les stades les plus âgés. Il existe un certain parallélisme entre les variations que l'on observe dans la morphologie externe des images et celle des larves. La forme du pronotum, chez les premiers, et celle des renflements parasagittaux, chez les secondes, sont très constantes à l'intérieur de chaque population mais difficiles à décrire ou à schématiser. Le chagrin entre les points, sur le pronotum des imagos, ou la répartition des mamelons, sur les tergites des larves, sont des caractères qui paraissent au premier abord beaucoup plus tranchés mais les fluctuations intraspécifiques sont plus importantes (voir Steffan 1958 pour les différences entre E. aenea et E. maugetii, sub nom. megerlei).

Les trois espèces possèdent une période de reproduction largement étalée. Chez E. aenea, la ponte s'effectue de Juin à Octobre, les nymphoses présentent un maximum en Mai.

Nous avons enfin fourni quelques données préliminaires sur l'étude de la chétotaxie. Cette étude n'apportant pas d'éléments de diagnose spécifique, but principal de ce travail, n'a pas été poursuivie sur la totalité du corps. Des comparaisons sommaires avec des larves d'autres genres d'Elminthidae montrent cependant que la chétotaxie larvaire présente un intérêt certain pour l'interprétation des homologies et des relations phylogéniques.

Pupae and pupal exuviae were collected by drift and hand netting from 27 sites on 10 streams in the Sierra Nevadamountains in 1986 and 1987. The sites represented an altitudinal range from 340 m to 2100 m. The pupal exuviae collections revealed a composite fauna of 143 species. Eukiefferiella (12 spp.) and Tvetenia (3 spp.) were dominant both taxonomically and numerically along most of the altitudinal profile, followed by Cricotopus (11 spp.), Orthocladius (9 spp.) and Diamesa (7 spp.). The altitudinal distribution of the 99 most common species is shown and compared with those obtained in other Europeanstreams or rivers, especially in the Pyrenees. The general pattern of altitudinal zonation shows an increase in speciesrichness from the headwaters (< 2000 m : 58 spp.) toward the middle reaches (1000-1600 m : 121 spp.). The theoreticallyexpected highest species richness in the foothill reaches (> 1000 m : 113 spp.) was not obtained. The periods of reduced or intermittent flow, the domestic organic inputs and the narrowness of the channels in the foothill reaches appear responsible for the decrease of the species richness of the chironomid communities.

An investigation into bryophyte communities in karst Jankovac Stream (Papuk Nature Park, Croatia) was carried out once a month from July 2008 to June 2009. Samples were taken from two lotic microhabitats: (i) Jankovac Spring (JS), a hypocrenal habitat with dense bryophyte clusters (90% bottom cover) and (ii) Jankovac Waterfall (JW), with scattered bryophyte clusters (50% bottom cover). At the same time, seston samples were collected during the spring as the source site and after the JW, as the outflow site. The goals of this study were to understand the (i) algal, protozoan and metazoan bryophyte community assemblages in these two lotic microhabitats, (ii) influence of environmental factors on the structuring of the bryophyte community and (iii) structure of seston along the longitudinal profile. A total of 172 taxa were determined: 68 algae, 55 protozoa, 24 meiofauna and 25 macroinvertebrates. Statistically significant differences between two microhabitats differing in percentage of bryophyte cover were established testing 13 environmental parameters. In dense bryophyte clusters, community structure was determined by flow velocity and pH, and macroinvertebrates achieved higher diversity and abundance. On the contrary, in scattered bryophyte coverage algae, protozoa and meiofauna reached higher abundance and diversity governed by the amount of suspended organic matter and epiphyton. In contrast to previous studies, the inverse ratio of community diversity and abundance versus percentage of bryophyte cover was established. We assume this to be the result of an enrichment of the scattered bryophyte clusters by upstream seston. Additionally, the effects of anthropogenic hydromorphological disturbance are reflected in macroinvertebrate diversity and abundance reduction.