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True flies comprise approximately one-tenth of all animal species on Earth, yet despite their prevalence and ecological significance in freshwater ecosystems, members of the insect order Diptera are frequently neglected in stream studies. This absence or inconsistency regarding Diptera in literature and taxonomic lists may leave readers with a sense of discrepancy. To illustrate this underrepresentation in quantitative ecological investigations, we conducted a targeted literature-based meta-analysis, assessing the average level of Diptera identification and the reported number of families. These findings were compared to data from 639 quantitative samples collected across six European ecoregions (Mediterranean, Alpine, Continental, Balkanic, Pannonian, Boreal) during six, bimonthly repeated sampling campaigns in 2021 and 2022. Our analysis revealed that, compared to other macroinvertebrate groups, Diptera were typically identified at a less detailed level, often only to the family level, thereby failing to fully represent Diptera diversity, especially regarding rare, less abundant families. In our review of literature studies, we identified references to a total of 40 families. Notably, Chironomidae, Ceratopogonidae, and Simuliidae were consistently represented across the majority of studies, whereas nearly half of the families were exclusively mentioned in one or two studies. No significant differences were found in the number of families across continents or various habitat types. In our case studies the number of families was significantly higher than in European stream studies, suggesting that several rare families occasionally completely neglected during sampling, sample sorting or identification. We explored potential connections among Diptera assemblages through correlation and coexistence analyses. Our results highlighted the significant influence of the more frequent Chironomidae, Ceratopogonidae, and Simuliidae on the presence or absence of other families. While correlations between Diptera families were identified, attempts to develop a predictive model for the diversity and occurrence of minor families based on the abundance of major ones proved inconclusive. For future quantitative studies on macroinvertebrate communities, it is essential to recognize, identify and incorporate less abundant Diptera families, even on family level, or in higher taxonomic resolution, if possible, to enhance understanding and prevent the loss of information concerning this compositionally and functionally uniquely diverse insect group, which represent a significant part of the entire community, and gain a better understanding on their interactions with other aquatic groups. [ABSTRACT FROM AUTHOR]

Alpine streams face rapid hydrological changes due to the effects of global warming, glacier melting, and increased water uses such as hydropower production. Defining environmental flows (e‐flow) is crucial to mitigate the ecological impacts of flow alterations. Among e‐flow assessment methods, hydraulic habitat models predict changes in habitat suitability for aquatic species under different flow scenarios. They couple hydraulic models of stream reaches with biological models relating the abundance of taxa to microhabitat hydraulics. However, there is currently no suitable biological models for alpine, often fishless streams. In this study, we develop biological models for dominant macroinvertebrate taxa in alpine streams and compare their responses to hydraulics with those published in lowland streams. Using data collected in 150 microhabitats along a gradient of shear stress within five alpine streams, we performed generalized linear mixed models relating macroinvertebrate abundance to microhabitat hydraulics (shear stress, flow velocity, Froude number and water depth). We developed biological models for 41 taxa, and observed significant microhabitat selection for shear stress (18 taxa), velocity (20), Froude number (21), and depth (11). Most of them presented consistent responses across studied alpine streams, with shear stress and velocity as the main drivers. For common taxa, shapes of macroinvertebrate responses to hydraulics were comparable with those observed in lowland streams. Nevertheless, taxa preferred slightly lower shear stress in alpine streams compared to lowland streams, probably due to high‐fine sediment and oxygen concentrations, especially for taxa feeding on autochthonous organic matter. Many (23%) abundant taxa are rheophilic in alpine streams, thereby threatened by flow reduction, including the glacial stream specialists Diamesinae and Rhithrogena delphinensis, which will be also affected by glacier retreat. Combined with hydraulic models, our biological models will facilitate more robust e‐flow assessments, thereby reducing the impacts of flow alterations on alpine aquatic ecosystems. [ABSTRACT FROM AUTHOR]

Ongoing hydrological alterations due to climate change and anthropogenic uses of water have major implications for freshwater biodiversity. Quantifying the relative effects of environmental variables on macroinvertebrates is required to predict biological responses to hydrological alterations. To date, no study simultaneously examined the effects of physico‐chemistry, hydraulics, and hydrology on the distribution of alpine macroinvertebrate communities and taxa. In this study, we aimed to quantify the relative correlation between these environmental variables and macroinvertebrate community composition and structure.We sampled macroinvertebrates at 66 stream sites located in three catchments in the French Alps. We characterised the proximate habitat at each site using 11 variables describing measured physico‐chemistry and hydraulics, and simulation‐based hydrology. We described relationships between community structure and the environment using a co‐inertia analysis and modelled individual taxa abundance with generalised linear mixed models.The co‐inertia revealed a significant co‐structure between the environmental and macroinvertebrate matrices. Glacier‐influenced sites with high turbidity and summer flow exhibited similar community composition with low total abundance. Sources at high altitude and sites with low glacial influence, exhibiting high summer flow and flow velocity, were dominated by Diamesinae, Rhithrogena spp., Dictyogenus spp., and Baetis alpinus. Streams fed by rainfall/snowmelt and valley sources, associated with higher temperature, conductivity, and monthly discharge variability were characterised by higher richness and abundances. Models indicated that the three types of proximate habitat variables significantly contributed to the macroinvertebrate distribution. Turbidity was strongly negatively associated with macroinvertebrate abundances. Increasing flow velocity and summer flow had significant (mainly negative) effect in 43% of models.The co‐structure between communities and proximate habitat variables was shared by the three catchments. For most individual taxa, catchment identity did not influence abundance models and cross‐validations indicated transferable effects of proximate habitat variables among alpine catchments.Our results can be used to infer responses of alpine macroinvertebrates to multivariate environmental changes. Understanding the relationships between macroinvertebrates and environmental variables help to predict how communities and taxa will be affected by habitat alterations due to ongoing hydrological changes and resulting physico‐chemical conditions. [ABSTRACT FROM AUTHOR]

River networks are among Earth's most threatened hot-spots of biodiversity and provide key ecosystem services (e.g., supply drinking water and food, climate regulation) essential to sustaining human well-being. Climate change and increased human water use are causing more rivers and streams to dry, with devastating impacts on biodiversity and ecosystem services. Currently, more than a half of the global river networks consist of drying channels, and these are expanding dramatically. However, drying river networks (DRNs) have received little attention from scientists and policy makers, and the public is unaware of their importance. Consequently, there is no effective integrated biodiversity conservation or ecosystem management strategy of DRNs. A multidisciplinary team of 25 experts from 11 countries in Europe, South America, China and the USA will build on EU efforts to assess the cascading effects of climate change on biodiversity, ecosystem functions and ecosystem services of DRNs through changes in flow regimes and water use. DRYvER (DRYing riVER networks) will gather and upscale empirical and modelling data from nine focal DRNs (case studies) in Europe (EU) and Community of Latin American and Caribbean States (CELAC) to develop a meta-system framework applicable to Europe and worldwide. It will also generate crucial knowledgebased strategies, tools and guidelines for economically-efficient adaptive management of DRNs. Working closely with stakeholders and end-users, DRYvER will co-develop strategies to mitigate and adapt to climate change impacts in DRNs, integrating hydrological, ecological (including nature-based solutions), socio-economic and policy perspectives. The end results of DRYvER will contribute to reaching the objectives of the Paris Agreement and placing Europe at the forefront of research on climate change. [ABSTRACT FROM AUTHOR]

The aim of this work was to construct a score issued from a machine learning system with self-improvement capacity able to predict the fate of an ART embryo incubated in a time lapse monitoring (TLM) system. A retrospective study was performed. For the training data group, 110 couples were included and, 891 embryos were cultured. For the global setting data group, 201 couples were included, and 1186 embryos were cultured. No image analysis was used; morphokinetic parameters from the first three days of embryo culture were used to perform a logistic regression between the cell number and time. A score named DynScore was constructed, the prediction power of the DynScore on blastocyst formation and the baby delivery were tested via the area under the curve (AUC) obtained from the receiver operating characteristic (ROC). In the training data group, the DynScore allowed the blastocyst formation prediction (AUC = 0.634, p < 0.001), this approach was the higher among the set of the tested scores. Similar results were found with the global setting data group (AUC = 0.638, p < 0.001) and it was possible to increase the AUC of the DynScore with a regular update of the prediction system by reinforcement, with an AUC able to reach a value above 0.9. As only the best blastocysts were transferred, none of the tested scores was able to predict delivery. In conclusion, the DynScore seems to be able to predict the fate of an embryo. The reinforcement of the prediction system allows maintaining the predictive capacity of DynScore irrespective of the various events that may occur during the ART process. The DynScore could be implemented in any TLM system and adapted by itself to the data of any ART center. Abbreviations: ART: assisted reproduction technology; TLM: time lapse monitoring system; AUC: area under the curve; ROC: receiver operating characteristic; eSET: elective single embryo transfer; AIS: artificial intelligence system; KID: known implantation data; AMH: anti-Müllerian hormone; BMI: body mass index; WHO: World Health Organization; c-IVF: conventional in-vitro fertilization; ICSI: intracytoplasmic sperm injection; PNf: pronuclear formation; D3: day 3; D5: day 5; D6: day 6; GnRH: gonadotrophin releasing hormone; FSH: follicle stimulating hormone; LH: luteinizing hormone; hCG: human chorionic gonadotropin; PVP: polyvinyl pyrrolidone; PNf: time of pronuclear fading; tx: time of cleavage to x blastomeres embryo; ICM: inner cell mass; TE: trophectoderm; NbCellt: number of cells at t time; FIFO: first in first out; TD: training data group; SD: setting data group; R: real world [ABSTRACT FROM AUTHOR]

Microhabitat selection models are frequently used in rivers to evaluate anthropogenic effects on aquatic organisms. Fish models are generally developed from few rivers, with debatable statistical treatments for coping with overdispersed abundance distributions. Analyses of data from multiple rivers are needed to test their transferability and increase their relevance for stakeholders. Using 3,528 microhabitats sampled in nine French rivers during 129 surveys, we developed models for 35 specific size classes of 22 fish species. We used mixed‐effects generalized linear models (accounting for multiple surveys), involving B‐spline transformations (accounting for nonlinear responses) and assuming a negative binomial distribution (accounting for abundance overdispersion). We compared models of increasing complexity: no selection (M1), an "average" selection similar in all surveys (M2), two models with different selection across surveys (M3–M4). Of 132 univariate cases (specific size classes by habitat), 63% indicated selection for depth, 71% for velocity, 45% for substratum size and 13% for substratum heterogeneity. A total of 50 models were retained, involving 26/35 specific size classes. Model fits indicated low explained deviance (R2MF < 0.19) and higher rank correlations (ρ < 0.69) between observed and modelled values. However, Bayesian posterior predictive checks validated these results since excellent fits would generate R2MF lower than 0.59 and ρ lower than 0.78. We found high transferability among rivers and dates, because (a) M2 was the most appropriate in 26/50 cases; (b) the R2MF and ρ values by M2 was, respectively, 72% and 75% of that explained by the complex M4 and (c) independent river cross‐validations showed good transferability. Bivariate models for selected specific size classes improved univariate model fits (ρ from 0.30 to 0.38). Overall, using a nonlinear mixed‐effect approach, our results confirmed the relevance of "average" models based on several rivers for developing helpful e‐flow tools. Finally, our modelling approach opens opportunities for integrating additional effects as the spatial distribution of competitors. [ABSTRACT FROM AUTHOR]

The first internal transcribed spacer (ITS-1) of ribosomal RNA of 5 individuals of unknown pisidiid clams collected over several years in the Rhone river basin was extracted to specify their taxonomic position. The phylogenetic tree obtained from the comparison of these sequences to those of 19 species available in the NCBI genetic database is in good agreement with the phylogenetic structure of Sphaeriinae and revealed that the unknown bivalves belong to the North American species Euglesa compressa. This invasive mollusk has now colonized the major French river basins and could be responsible for the major decline of E. supina in the areas where it has settled. The main features of E. compressa are also presented. [ABSTRACT FROM AUTHOR]

Principal threats to running waters are linked to human-made discharge modifications, but tools to predict the quantitative consequences of flow restoration for benthic invertebrates in large rivers remain untested., Quantitative benthos samples from two bypassed reaches (Pierre-Bénite - PBE - and Chautagne - CHAU) of the French Rhône River were collected during four years each before and after minimum flow increases (from 10 to 100 m3 s−1 at PBE and from 10 to 50 m3 s−1 at CHAU). These samples provided observed ln-density changes for the 50 and 62 ( PBE and CHAU, respectively) most abundant taxa (typically species or genera). For about half of the 'model' taxa among them, distinct preference models for bottom shear stress categories were available from four reaches of the Upper Rhône River and from various German rivers. Linking these preference models with a statistical hydraulic model predicting frequencies of shear stress categories for any given discharge, we predicted ln-density changes of the model taxa after restoration., Community structure of the abundant taxa changed clearly and rapidly after restoration at PBE but less clearly at CHAU. Our predictions explained a considerable amount of mean ln-density changes of our model taxa observed after restoration (75 and 30% at PBE and CHAU, respectively). They also explained (67 and 40% at PBE and CHAU, respectively) the model taxa scores along the principal components analysis axis that summarised the community variations of all abundant taxa before and after restoration. For taxa not identified to species (assessed as genus, tribe or family), the predicted ln-density changes were sometimes inaccurate at PBE (a Lower Rhône site), suggesting that the transferability of preference models for taxonomic levels above that of species can be problematic., If further developed, statistical habitat models focussing on ecologically relevant physical variables (in our case shear stress) should enable reliable quantitative assessments of associations between flow restoration efforts and achievable ecological improvement. [ABSTRACT FROM AUTHOR]

Data-rich restoration experiments offer opportunities to test the ability of bioassessment tools, such as those currently used to assess the 'ecological status' of waterbodies targeted by the European Water Framework Directive, to detect observed ecological changes., Minimum flow increases in four regulated reaches of the French Rhône River modified the invertebrate and fish communities in a predictable way, as detailed in other articles of this Special Issue. We tested the ability of several fish and macroinvertebrate metrics currently used in bioassessment to detect these changes. In addition, we considered changes in metrics that are expected to respond specifically to flow increase. These metrics were related to the habitat requirements of species, the ecological specialisation of communities and the abundance of macroinvertebrate functional groups (seen as surrogates for ecosystem attributes)., For invertebrate communities, bioassessment metrics based on richness had equivocal responses to restoration and the Potamon-Type Index demonstrated no or contradictory responses to restoration. The French biotic index was not sensitive to restoration and instead depicted spatial differences in biological quality. For fish communities, the French fish index was marginally sensitive in the reach with the largest minimum flow increase and some of its metrics were sensitive in other reaches., Contrasting with commonly used bioassessment indices and metrics, several metrics related to habitat requirements appropriately indicated the observed changes in community structure. Large flow changes increased the proportion of fish and macroinvertebrate individuals with preferences for midstream habitats, fast currents, deep waters and/or coarse substrates. However, these changes did not translate into the expected increase in ecological specialisation. In addition, functional metrics indicated that restoration led to higher proportions of grazers and higher availability of suspended food for filtering collectors, suggesting a return to the ecological conditions of a large river., The mixed and potentially contradictory responses of the different metrics confirm the difficulty of establishing benchmarks for ecological indicators in large-regulated rivers and the need to design appropriate bioassessment metrics. [ABSTRACT FROM AUTHOR]

Assessing how populations respond to ecological restoration is particularly difficult because their abundance results from many sources of variation. In addition, abundance estimates depend on sampling efforts that are limited by financial or practical constraints., We used local abundance counts from the Rhône river restoration monitoring programme to quantify how sampling strategies and population characteristics influenced statistical power for detecting restoration effects., We first fitted observed changes in abundance of 13 fish taxa and 35 invertebrate taxa collected in microhabitats of four restored reaches of the Rhône river over 15 years, using a generalised linear mixed model. The model accounted for a restoration effect, random temporal variation between field surveys and spatial variation within surveys (i.e. microhabitat variation in abundance was assumed to follow a negative binomial distribution). We then used numerical simulations to calculate the statistical power (i.e. the probability of detecting a true change) and the type I error (the probability of detecting a non-existent change) associated with various hypotheses of restoration effect size, mean abundance and temporal and spatial variation., Model fits revealed that accounting for temporal variation is needed to reduce type I error associated with the effect of restoration. Significant abundance changes were observed for 27 of 104 (26%) of the taxa-reach combinations., When assuming temporal variation and population characteristics typical of our data sets, power simulations showed that the probability of detecting a moderate change (50-200%) in abundance was <38% in all tests. The average probability of detecting large changes (500-1000%) was 61%. In these conditions, power was increased by low spatial variation and high sampling effort. Large numbers of surveys (e.g. 16 instead of 4) increased the power by 20 points if surveys were balanced before and after restoration., Because our simulations covered a wide variety of population characteristics and sampling strategies, they can be used a priori to determine which sampling strategy is best adapted for detecting restoration effects from repeated abundance counts. [ABSTRACT FROM AUTHOR]

A multiple-trait-based approach can provide predictions and interpretations of the responses of freshwater communities to river restoration that apply in different taxonomic contexts. We compared the observed and predicted effects of restoration on sets of traits in fish and invertebrate communities in four reaches of the Rhône River. Restoration included minimum flow increases in three bypassed main channels and the reconnection of eight floodplain channels., Predictions (described in detail in three other articles in this Special Issue) were based on habitat models that related the density of modelled taxa to their physical habitats. We used trait information extracted from the literature to translate predicted taxonomic changes into predicted changes in traits. Observed changes in traits calculated for modelled taxa and for all taxa in the community were both compared to predictions., In 10 of 12 cases, observed changes in traits correlated with predicted ones. With few exceptions, the agreement was higher for fish and invertebrates in the main channels than for invertebrates in floodplain channels. Predictions translated to the trait category level improved those at the taxonomic level in 5/6 and 4/6 cases for modelled taxa and all taxa, respectively. However, the improvement was statistically significant according to a null model for 1/6 and 3/6 cases for modelled taxa and all taxa, respectively., The validation of trait predictions suggested that traits related to locomotion and attachment, as well as general biology and physiology, were particularly suited to predicting and understanding the effects of physical restoration. For example, after restoration, clingers and passive filter feeders dominated invertebrate communities in the main channels, whereas invertebrate communities in the floodplain underwent a selection of traits frequent in running water (clingers, flattened shape and gill respiration). Within fish communities, the periodic life-history strategy that characterises fish species in downstream reaches (long life span, large body, late sexual maturity) increased with restoration, whereas the opportunistic strategy decreased., Our results suggest that a better understanding of how hydraulics shapes traits in riverine systems is critically needed for assessing the effects of restoration measures impacting flow. In addition, existing trait databases (especially for fish) should be expanded to better reflect the energetic trade-offs that organisms must make in various flow contexts. [ABSTRACT FROM AUTHOR]

Leptocerina is an endemic Afrotropical genus of Trichoptera, with 19 species documented but only five partially described at the larval stage. The first description of Leptocerina pauliani (Ross 1957) larva by Marlier Marlier (1982) included very few illustrations, making comparisons with other species challenging. I present a revised description of the L. pauliani larval stage, using specimens collected from the River Marsouins in La Réunion Island. I apply a focus stacking approach for emphasizing coloration patterns and providing a detailed description of larval characters. Criteria for distinguishing L. pauliani from the other species of Leptocerina already described or partially described for the larval stage are discussed.

The morphology of the larvae of three French species of Psychomyiinae: Psychomyia pusilla, Metalype fragilis and Paduniella vandeli are described. A set of characters on the head, the prothorax, and the anal prolegs makes it possible to identify the larvae of the fourth and fifth instars. A brief study of the world distribution of the genera Psychomyia, Metalype, and Paduniella is presented. An examination of the larvae of these three genera from literature data and personal observations offered us the possibility to test the validity of the set of characters obtained for the three French species. A key (with comments) of the three genera is provided.

Co-occurrence of mature larvae and male pharate pupae in benthos samples from the Loire River enabled descriptions of the larva of Homilia leucophaea. Using characters of the head capsule, the labrum, the meso- and metanotum, and the pro- and metathoracic legs, we compared H. leucophaea with larvae of six western European Athripsodes species, including a larval key to these species. The larva of H. leucophaea shares characters with some of the six Athripsodes species. However, without a phylogenetic analysis including larvae, pupae, and adults of Homilia species from the Afrotropical Region, it is currently impossible to decide about a potential synonymy between Athripsodes and Homilia.