The paper proposes a new biological method for assessing the quality of lakes. It is based on the comparison of littoral and profundal macroinvertebrate communities sampled in soft sediments. Two depths were sampled: one at the littoral zone (Zl = 2m) to define a littoral index (Bl ) related to the biogenic potential of the lake (quantitative data), the other at the deep zone (Zf = 0.66 Zmax) to define a taxonomic deficit index (Df ) connected with the quality of the water-sediment interface in deep zone (qualitative data). These two indexes were combined in a Lake Biotic Index (LBI), with a range from 0 to 20, which gives an evaluation of the biogenic capacity of a lake to the development of macroconsumer communities. Using the Bl and Df values any lake can be plotted on a typological graph which is helpfull to characterize lakes both quantitatively (oligo- to polybiotic) and qualitatively (eu- to dysbiotic). Lake Châlain (French Jura) is presented as an example of the method application with its macrofauna and the index calculation. Then, this lake was included in the typological graph with nine other French lakes studied using the same method. Each lake, characterized by its Bl, Df and LBI values, can be compared to the others in a typological scheme. The proposed indexes are discussed and bases for interpretation of the results are presented. The proposed classification of lakes gives an evaluation of their biogenic capacity concerning macroconsumers and can be usefully compared with other classifications, especially with trophic and sediment types, in functional studies as well as in lake diagnosis, in the context of the Water Framework Directive (Directive 2000/60/CE).

Benthic macroinvertebrates are an essential component of freshwater environments. The ecotoxicological risk of benthic communities, estimated through the assay of biochemical markers, can be used as an early warning signal for environment alterations. In this work the activities of a number of enzymes, regarded as potential biomarker of exposure to pollutants (catalase, acetylcholinesterase, glutathione-S-transferase) was determined in homogenates of whole organisms. Specimens were collected in the rivers Taro and Ticino, northern Italy, in stony bottom reaches in five and three stations respectively. The orders of aquatic Insects Diptera, Plecoptera, Odonata, Ephemeroptera and Trichoptera, the Crustacea Amphipoda, and Annelida Oligochaeta were examined. Additional enzymes, such as NADP-dependent malate dehydrogenase, isocitric dehydrogenase, glucose-6phosphate dehydrogenase, alcohol dehydrogenase, and lactate dehydrogenase were considered in the study. Results emphasize significant differences among taxa concerning the specific activity of most enzymes.

We present the results of a four-years monitoring program of Lake Duchessa, a small shallow subalpine lake situated at 1788 m a.s.l. in central Apennines (Italy). From 1997 to 2000, during snow free periods, we regularly measured conductivity, pH, macrophyte cover and water transparency. Contemporarily, 4 water samples were collected to determine nutrient (NH3-N, NO2N, NO3-N and PO4-P) and phytoplanktonic chlorophyll a concentrations. Taxonomic compositions of aquatic macrophytes, zooplankton and macroinvertebrates were also determined. Inter- and intra-annual variation of water chemistry and phytoplankton biomass were addressed. Lake Duchessa showed some limnological aspects proper to lowland eutrophic situations due to livestock grazing in the watershed pastures and watering in the lake. In particular, nutrient concentration and phytoplankton biomass reached extremely high values, and lake community was relatively poor. However, despite the high nutrient loading, phytoplankton biomass collapsed in August 1997. In the same occasion, lake water became transparent and remained clear until the end of 1999. The occurrence of this clear water phase and its surprising span may be related to the reduction of tench population (due to a natural fish kill observed during the study) and to the extension of Potamogeton pectinatus L. and Myriophyllum spicatum L. cover. Our results support early observations that water transparency (i.e. environmental quality) of eutrophic shallow lakes can be improved also when nutrient loading is not reduced. Many of the Apennine lakes and ponds situated at high altitudes show conditions similar to those of Lake Duchessa. Therefore this study highlights the ecological processes to be considered in a reliable management of these freshwater systems.

The rules governing the allocation of available resources to varying physiological processes are evaluated in three physiologically-based models of individual Daphnia. In laboratory experiments using a single clone, subjected to varying regimes of food deprivation, growth was found to vary inversely with food level, ceasing in the absence of food, implying that growth allocation is derived directly from food. Reproductive investment was reduced under food deprivation, ceasing at low food levels. By exposing juvenile and adult daphnia to varying food deprivation regimens during different periods within their intermoult interval, it was shown that instar durations vary as a function of body size and food availability independent of the age of the animal. For the first time, the role of variable instar duration, which critically influences physiological processes such as growth, moulting and reproduction in adult females, that has been neglected by existing Daphnia models, is explicitly incorporated in a physiological allocation model. The consequent model provides a simplified framework for modelling the consequences of food deprivation in cladocerans which has important application in population modelling and environmental risk assessment.

Ecotoxicological studies with cladocerans frequently assess the individual growth of the organisms. Measures upon living organisms should be avoided once they can lead to their death or affectation, therefore constraining the results. In this way, and considering that cladocerans species go through series of moults along their life cycle, measures upon the moult are preferred in almost all the studies. Thus, the establishment of allometric relations is required to enable feasible estimations of diverse growth parameters. Exopodite and total body length of two autochthonous (Daphnia longispina; Ceriodaphnia pulchella) and two standard (Daphnia magna; Ceriodaphnia dubia) living daphnids were registered. Regression analysis was applied in order to establish a relation between the two allometric measurements in each species. As high R-squared values were reached in all species, the obtained equations can be used as reference for estimations of body length in face of the «moult» exopodite length measure. Consequently, this work provides a support reference for ecotoxicological studies performed in lab with these species.

Aquatic microfungi play a fundamental role in organic matter decomposition in fluvial ecosystems. These micro-organisms degrade leaf recalcitrant compounds like lignin, thereby enhancing the utilization of organic material by the microbial community. The main input of allochthonous organic matter in Mediterranean streams occurs during the autumn. In-stream breakdown processes can be affected by high physical abrasion during flooding but changes in stream water chemistry may also affect decomposition enzymatic activities of stream microorganisms. We measured two ligninolytic activities (phenol oxidase and peroxidase) and a cellulolytic activity (cellobiohydrolase) in leaves, branches, sand and gravel substrata in a reach of a Mediterranean stream. Highest ligninolytic activities were measured in biofilm developed on inorganic substrata (sand and gravel) where also accumulated the highest fungal biomass (ranging from 3.3 x 10-4 to 7.22 mg Ergosterol gAFDM-1) especially in sand substrata. Conversely, cellulolytic activities were significantly higher in biofilm on organic substrata (leaves and branches). Physical and chemical factors, such as discharge and stream water nutrient concentration (Dissolved Inorganic Nitrogen) were affecting enzymatic activities, particularly enhancing the phenol oxidase. Moreover, the chemical composition of the available OM (high cellulose in leaves, high lignin in detritic material) strongly influenced the decomposition activity in each biofilm. A precise description and quantification of the benthic substrata was used to obtain enzymatic activity values in terms of stream reach. Those results showed a temporal pattern in the decomposition activities in the reach, beginning with the decomposition of cellulose (October) followed by lignin compounds (November and December).

Integrated ecological models are of great potential as predictive tools in decision support of river management. Such models need to be transparent and consistent with the existing expert knowledge, and give the river manager adequate information regarding their inherent uncertainty. One way to fulfil these needs is through the use of Bayesian Belief Networks (BBNs). Such networks represent cause-and-effect assumptions between system variables in a graphical structure. To establish the potential of Bayesian Belief Networks in river management, a small-scale study was performed with the aim of assessing the success of prediction of macroinvertebrate taxa in rivers by means of a selected number of environmental variables. Gammaridae and Asellidae were chosen because of their high relative abundances in small and large brooks in contrast to other macroinvertebrate taxa. Based on one-layered BBN networks, the predictive capacity of the models was assessed by means of the number of Correctly Classified Instances (CCI) and Cohen’s Kappa (K). The performance of these models was moderate to good for presence/absence classifications but showed a low to moderate performance when predicting abundance classes. When extending the former BBN network to a two-layered one, enhancing the number of links and variables, no obvious improvement in model performance was detected. The results indicate that thoughtful input variable selection as well as sensitivity analysis will improve the models for practical use in river restoration management.

The assemblage patterns of pelagic Cladocera species were investigated in a meso-eutrophic reservoir from January 2000 to December 2002. Trends of environmental factors (water temperature, conductivity, pH, and nutrient concentrations), as well as of biotic factors (availability of potentially edible phytoplankton and densities of herbivorous and carnivorous copepods) were assessed. Zooplankton community was dominated by Cladocera and Copepoda. Assemblage patterns for Cladocera were identified by performing a cluster analysis on abundance data of the dominant species: Daphnia longispina, Ceriodaphnia pulchella, Bosmina longirostris and Diaphanosoma brachyurum. In winter and spring, Daphnia was dominant. In early summer and end of autumn, Ceriodaphnia and Daphnia coexisted. During summer, Ceriodaphnia was dominant and coexisted with Diaphanosoma. Bosmina was present in low densities during the whole study period. Cladoceran populations exhibited non-synchronous peaks of abundance, evidencing different ecological optima. Temperature seemed to be the main structuring factor of this assemblage. The way biotic interactions influenced pelagic cladoceran assemblage in this reservoir was not clear and needs further research.

We tested the individual and joint effects of stream order, riverbed morphology (i.e. pool-riffle sequence), and season on the structural (i.e. species composition, density and richness) and functional (i.e. percent ratio of shredders, collectors, scrapers, and predators) properties of caddisfly assemblages in a closely natural headwater system (Börzsöny Mts., North Hungary). Each factor, both individually and in interaction had a significant effect on caddisfly assemblages as shown by MANOVA analyses. To clarify the effects of stream order, riverbed morphology and season on caddisflies, assemblage properties were also separately studied by ANOVAs. Percent ratio of shredders and collectors were strongly affected by all factors, whereas other attributes were not always sensitive to stream order, season and riverbed morphology. In contrast, species compositions of the reaches differing in stream order and riverbed morphology were significantly different. Our findings on the contrasting differences in shredder composition between riffles and pools may suggest that not only riparian vegetation, but also instream habitat features could shape the accumulation and retention of particulate organic matter (in streams with pool-riffle heterogeneity).

The life cycle of Musculium lacustre populations in the Saône river at Lyon was studied over a three-years period. Following the growth period which occurs from March to June, adults released larvae, then disappeared during the summer. Only a few newborn of the new generation that appeared in May and June grow and give birth to a second generation at the end of summer or in autumn. Most of the juveniles of the first generation estivate, then hibernate with those of the second generation until the following spring. The individuals of each generation only reproduce once (semelparity). Longevity of M. lacustre is from 13 to 14 months. In 2001, the spring flood disturbed the progress of the life cycle and delayed the appearance of the new generation for one month. In 2003, a large accumulation of dead leaves at the beginning of winter and high spring temperatures led to considerable production of larvae. However, this was not followed by an increase in numbers: high mortality among the newborn occurred during May and June. These observations suggest that M. lacustre populations of the Saône are habitually food-limited. Nonetheless, the life cycle strategy adopted by this bivalve enabled it to withstand the high summer temperatures of 2003 as opposed to other Sphaeriidae (Pisidium) which disappeared in August.

South-eastern France is highly interesting for hydroentomology, in particular for caddisflies. Its lower zones are communication corridors for the fauna of the Apennines on one hand, and for that of the Pyrenees and Cantabric Cordillera on the other hand. At the same time, its high mountain massifs are inhabited by a fauna including endemic elements vicarious with other Alpine massifs, and having sometimes a relict character. The present paper insists on the most interesting discoveries made by studying important collections from springs, streams and mountain rivers in various parts of the zone: taxa new for science (Plectrocnemia geniculata prealpina n. ssp., Hydropsyche subalpina n. sp, Drusus biguttatus teunisseni n. ssp., Alpopsyche n. g.), taxa new for the French fauna (Tinodes antonioi, T. dives consiglioi, Hydropsyche pictetorum, H. tenuis, Ylodes canus), and additional information (morphology, distribution) for a number of species.

The results of 32 seasonal sampling sessions in 2000 were used to assess the dynamics of autotrophic picoplankton (APP), with special reference to the cyanobacterial component in Strzeszynskie Lake, a eutrophic lake in mid-western Poland. The abundance of picocyanobacteria (Pcy) fluctuated from 1.2x104 to 8.1x105cells mL-1 and the average abundance and biomass were 2.0x105cells mL-1 and 0.094 mg L-1, respectively. Pcy development was characterised by maxima in spring and summer. The summer maximum was twice the spring Pcy numbers. Eukaryotic APP (E-APP) were also present but in low numbers and their annual average contribution to the total APP community was only about 0.3% in abundance and about 3% in biomass. The spring Pcy community was dominated by single-celled cyanobacteria (S-Pcy) and in summer by colonial forms (C-Pcy). Throughout the sampling period, C-Pcy constituted on average 55% of the total Pcy and up to 90% in summer. C-Pcy abundance was significantly and positively correlated with water temperature (r=0.40, p=0.023, n=32). S-Pcy exhibited a distinct seasonal variation in FDC, ranging from 10% to 35%. Most FDC values above 30% were recorded from late May to mid July.

Collections of Chironomidae from aquatic habitats on the Azores islands of São Miguel and Flores during August 1997 and on São Miguel, Terceira and Graciosa in September-October 1998, yielded 33 species-level taxa. Representatives of 16 taxa in three subfamilies are new generic / species records for the Azores archipelago: Tanypodinae - Procladius (Holotanypus) choreus (Meigen), Paramerina sp. griechenland, Zavrelimyia sp.; Orthocladiinae - Metriocnemus (Inermipupa) carmencitabertarum Langton et Cobo, Orthocladius (Eudactylocladius) sp., Psectrocladius limbatellus (Holmgren), Psectrocladius sp., Pseudorthocladius sp., Smittia contingens (Walker); Chironominae - Chironomus cingulatus Meigen, Chironomus cf annularius (De Geer), Glyptotendipes barbipes (Staeger), Glyptotendipes pallens (Meigen), Polypedilum nubifer (Skuse), Micropsectra sp. (cf lindrothi Goetghebuer), Paratanytarsus grimmii (Schneider). A revised checklist is provided, incorporating and updating previous records.

Zooplankton biomass was investigated monthly from September 1997 to August 1998 in a shallow eutrophic lake (San Miguel del Monte, Argentina). Duplicate samples of zooplankton were obtained from three stations with different limnological characteristics. The density of zooplankton community was dominated by rotifers and small cladocerans related to the trophic status of this shallow lake. The zooplankton biomass showed similar values to other eutrophic shallow lakes. The annual biomass distribution was bimodal (winter and summer peaks). The contribution of crustaceans, mainly copepods, determined the total biomass. The total zooplankton biomass was significantly correlated with chlorophyll «a» in the sampling station located at the deep part of this shallow lake. There were factors and processes promoting changes in the zooplankton biomass, such as food availability, grazing ability, fish predation, eutrophication process with alternation of turbid and clear water periods, and also the addition of organisms from the Salado River during floods.

Phyllognathopus bassoti Rouch, 1972, originally described from Long Island, Papua New Guinea, and later reported from the Philippines, is found for the first time in India. This subterranean species is redescribed and its ecology and zoogeography are discussed. Also, the systematics of the family Phyllognathopodidae is discussed and a key to genera and species is given. As a result of the taxonomic analysis, three species are here synonymized: Phyllognathopus insularis Chappuis, 1940 and P. camptoides Bozic, 1965 with P. chappuisi Delachaux, 1924; and P. volcanicus Barclay, 1969 with P. viguieri (Maupas, 1892). It has been observed that odonate nymphs prey on adults and copepodids of P. bassoti, an interaction not known until now.

Tanypus complanatus sp. n., Pseudosmittia remigula sp. n, and Polypedilum (Tripodura) silhoettarium sp. n. are described as male imagines and Clunio gerlachi sp. n. as male and female imago. The male imagines of Larsia pallidissima (Kieffer), Gymnometriocnemus (Gymnometriocnemus) mahensis (Kieffer), Pseudosmittia xanthostola (Kieffer) and Polypedilum (Polypedilum) glabripenne (Kieffer) are described for the first time. The male imagines of Paramerina minima (Kieffer), Smittia megalochirus (Kieffer) n. comb., Smittia mahensis (Kieffer) and Pseudosmittia melanostola (Kieffer); and the female imago of Pseudosmittia xanthostola (Kieffer) are redescribed. A key to the known chironomids of the Seychelles is given. Twenty-eight chironomid species are known from the Seychelles, 23 from the island of Mahé, 12 from Silhouette, 3 from Curieuse, 2 from Anonyme and 1 from each of Fregate, North and the coralline Alphonse. The likely marine intertidal species appears to have their closest relatives in Micronesia and the Pacific, while the freshwater chironomid fauna appear to have more Afrotropical relatives.

The Chironomidae fauna of ten large European rivers (Rhine, Elbe, Oder, Danube, Loire, Pripjat, Po, Maas, Garonne and Rhône) were investigated by analysing their ecological traits (longitudinal zonation pattern, saprobiological affinities, feeding types) using one-dimensional and multivariate methods. The results confirm the geomorphological differentiation of these rivers in two main types, i.e. gravel-type and sand-type rivers. The analyses of the Chironomidae traits also showed that transition zones separate the two main types of rivers.

A new species of Enchytraeidae, Cernosvitoviella tridentina sp.n., is described from alpine streams (Stelvio National Park, Trentino). C. tridentina sp.n. belongs to a group of species with spermathecae confined to the V segment; it particularly resembles Cernosvitoviella carpatica (Cernosvitov), C. minor Dozsa-Farkas and C. celere Nurminen, but differs from these species by some important anatomical features: the presence of small seminal vesicles, longer ectal ducts of the spermathecae and (from two first species) by deep incision of the posterior margin of the brain.

We studied the genus Pleuroxus (including Picripleuroxus) of the rainforests of Cameroon, making extensive use of trunk limb morphology. Six species were found. Pleuroxus aduncus, P. toumodensis, P. unispinus, Pleuroxus cf similis, P. laevis and P. denticulatus show differences in postabdomen, but also in the inner distal lobes (IDL) and endites (E1-E3) of the first trunk limb (P1), endopodites (EN) of the second limb (P2), exopodites (EX) and outer spines of the endopodite of the third limb (P3), and epipodites (EP)/ endopodites (EN) of the fourth and fifth limbs (P4 & P5). These limbs, previously believed to be structurally similar, are thus seen to be built according to a strongly conserved plan, yet with specific differences. The differences found do not coincide with Frey’s subdivisions of the genus based on external characters. Consequently, we cannot confirm the existence of a (sub)genus Picripleuroxus. Four species are shared with temperate to continental and subarctic Eurasia. Pleuroxus cf. similis is closest to a species originally described from Chile, and subsequently reported from Central Asia and Australia. It remains insufficiently characterized. Pleuroxus toumodensis is an African endemic, typical of gallery forests along rivers (from the Niger to the Nile). It is now also found in true rainforest waters. Pleuroxus unispinus was previously known only from Australia.

73 species and subspecies are reported from the North West of the Iberian Peninsula, including 10 new taxa described in the last four years. 14 species are new for the Cantabrian Cordillera, 1 for Galicia, 9 for the Sierra de la Demanda and 2 for the Sierra del Moncayo. The systematic status of some species is modified: Protonemura pyrenaica pyrenaica and P. pyrenaica asturica are restored to specific level; Leuctra lusitanica is considered as a subspecies of L. lamellosa; Nemoura cinerea umbrosa is a valid subspecies of N. cinerea cinerea. The stonefly faunistic lists of the Cantabrian Cordillera, Galicia, Demanda and Moncayo are updated. Species distribution patterns and faunistic relations with the neighbouring regions are analyzed. Classification and ordination analyses based on species presence, enable identification of bioclimatic and biogeographical patterns of Plecoptera distribution in the North of the Iberian Peninsula.