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Identification of ecosystem services, i.e. the contributions that ecosystems make to human well-being, has proven instrumental in galvanising public and political support for safeguarding biodiversity and its benefits to people. Here we synthesise the global evidence on ecosystem services provided and disrupted by freshwater bivalves, a heterogenous group of >1200 species, including some of the most threatened (in Unionida) and invasive (e.g. Dreissena polymorpha) taxa globally. Our systematic literature review resulted in a data set of 904 records from 69 countries relating to 24 classes of provisioning (N = 189), cultural (N = 491) and regulating (N = 224) services following the Common International Classification of Ecosystem Services (CICES). Prominent ecosystem services included (i) the provisioning of food, materials and medicinal products, (ii) knowledge acquisition (e.g. on water quality, past environments and historical societies), ornamental and other cultural contributions, and (iii) the filtration, sequestration, storage and/or transformation of biological and physico-chemical water properties. About 9% of records provided evidence for the disruption rather than provision of ecosystem services. Synergies and trade-offs of ecosystem services were observed. For instance, water filtration by freshwater bivalves can be beneficial for the cultural service ‘biomonitoring’, while negatively or positively affecting food consumption or human recreation. Our evidence base spanned a total of 91 genera and 191 species, dominated by Unionida (55% of records, 76% of species), Veneroida (21 and 9%, respectively; mainly Corbicula spp.) and Myoida (20 and 4%, respectively; mainly Dreissena spp.). About one third of records, predominantly from Europe and the Americas, related to species that were non-native to the country of study. The majority of records originated from Asia (35%), with available evidence for 23 CICES classes, as well as Europe (29%) and North America (23%), where research was largely focused on ‘biom, MCIU - Ministerio de Ciencia, Innovación y Universidades(CA18239), This study resulted from discussions facilitated by the EU COST Action CA18239. A.Z. was supported by an Anne McLaren Fellowship by the University of Nottingham. A.S.V. acknowledges support from FCT – Portuguese Foun dation for Science and Technology through the program Stimulus for Scientific Employment – Individual Support [contract reference 2020.01175.CEECIND] and Ministerio de Ciencia, Innovaci on y Universidades (Spain) through the 2018 Juan de la Cierva-Formaci on program [contract reference FJC2018-038131-I]. D.C.A. was supported by a Dawson Fellowship from St. Catharine’s College, Cam bridge. E.E. was supported by Portuguese national funds from FCT - Foundation for Science and Technology through projects UIDB/04326/2020, UIDP/04326/2020 and LA/P/0101/2020. [Corrections added on 22 July 2022, after first online publication: Funder details for Eduardo Esteves have been added in this version.]

Europe has a long history of human pressure on freshwater ecosystems. As pressure continues to grow and new threats emerge, there is an urgent need for conservation of freshwater biodiversity and its ecosystem services. However, whilst some taxonomic groups, mainly vertebrates, have received a disproportionate amount of attention and funds, other groups remain largely off the public and scientific radar. Freshwater mussels (Bivalvia, Unionida) are an alarming example of this conservation bias and here we point out six conceptual areas that need immediate and long-term attention: knowledge, threats, socioeconomics, conservation, governance and education. The proposed roadmap aims to advance research, policy and education by identifying the most pressing priorities for the short- and long-term conservation of freshwater mussels across Europe., COST - European Cooperation in Science and Technology(CA18239)

Molluscs are among the most diverse and widespread animal groups in freshwater habitats. Unfortunately, like most freshwater taxa, they are decreasing dramatically and are now among the most threatened animals on Earth, with many species already extinct or on the brink of extinction. Here, we review our current knowledge on the biodiversity and conservation of freshwater molluscs using the concept of knowledge shortfalls. We focus on seven previously proposed key shortfalls to review and analyse existing knowledge gaps relating to (1) taxonomy, the Linnean Shortfall; (2) distribution, the Wallacean Shortfall; (3) abundance and population dynamics, the Prestonian Shortfall: (4) evolution, the Darwinian Shortfall; (5) abiotic tolerances, the Hutchinsonian Shortfall; (6) traits, the Raunkiaeran Shortfall; and (7) biotic interactions, the Eltonian Shortfall. In addition, we address a new shortfall, which relates to the application and effectiveness of conservation measures, including assessments, methods, funding, and policies, the Ostromian Shortfall. Based on our review, we provide recommendations and suggest pathways to overcome these existing shortfalls. This work also introduces the articles in this special issue of Hydrobiologia, which represent key contributions to the First International Freshwater Mollusk Conservation Society Meeting held in Verbania, Italy, in 2018.

Invasive bivalves continue to spread and negatively impact freshwater ecosystems worldwide. As different metrics for body size and biomass are frequently used within the literature to standardise bivalve-related ecological impacts (e.g. respiration and filtration rates), the lack of broadly applicable conversion equations currently hinders reliable comparison across bivalve populations. To facilitate improved comparative assessment among studies originating from disparate geographical locations, we report body size and biomass conversion equations for six invasive freshwater bivalves (or species complex members) worldwide: Corbicula fluminea, C. largillierti, Dreissena bugensis, D. polymorpha, Limnoperna fortunei and Sinanodonta woodiana, and tested the reliability (i.e. precision and accuracy) of these equations. Body size (length, width and height) and biomass metrics of living-weight (LW), wet-weight (WW), dry-weight (DW), dry shell-weight (SW), shell free dry-weight (SFDW) and ash-free dry-weight (AFDW) were collected from a total of 44 bivalve populations located in Asia, the Americas and Europe. Relationships between body size and individual biomass metrics, as well as proportional weight-to-weight conversion factors, were determined. For most species, although inherent variation existed between sampled populations, body size directional measurements were found to be good predictors of all biomass metrics (e.g. length to LW, WW, SW or DW: R2 = 0.82–0.96), with moderate to high accuracy for mean absolute error (MAE): ±9.14%–24.19%. Similarly, narrow 95% confidence limits and low MAE were observed for most proportional biomass relationships, indicating high reliability for the calculated conversion factors (e.g. LW to AFDW; CI range: 0.7–2.0, MAE: ±0.7%–2.0%). Synthesis and applications. Our derived biomass prediction equations can be used to rapidly estimate the biologically active biomass of the assessed species, based on simpler biomass or body size measurements for a wide range of situations globally. This allows for the calculation of approximate average indicators that, when combined with density data, can be used to estimate biomass per geographical unit-area and contribute to quantification of population-level effects. These general equations will support meta-analyses, and allow for comparative assessment of historic and contemporary data. Overall, these equations will enable conservation managers to better understand and predict ecological impacts of these bivalves. Fil: Coughlan, Neil E.. The Queens University of Belfast; Irlanda. University College Cork; Irlanda Fil: Cunningham, Eoghan M.. The Queens University of Belfast; Irlanda Fil: Cuthbert, Ross N.. The Queens University of Belfast; Irlanda. Geomar-Helmholtz Centre for Ocean Research Kiel; Alemania Fil: Joyce, Patrick W. S.. The Queens University of Belfast; Irlanda Fil: Anastácio, Pedro. Universidade de Évora; Portugal Fil: Banha, Filipe. Universidade de Évora; Portugal Fil: Bonel, Nicolás. Université Montpellier II; Francia. Centre National de la Recherche Scientifique; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina Fil: Bradbeer, Stephanie J.. University of Leeds; Reino Unido Fil: Briski, Elizabeta. Geomar-Helmholtz Centre for Ocean Research Kiel; Alemania Fil: Butitta, Vince L.. University of Wisconsin; Estados Unidos Fil: Cadková, Zuzana. Czech University of Life Sciences; República Checa Fil: Dick, Jaimie T. A.. The Queens University of Belfast; Irlanda Fil: Douda, Karel. Czech University of Life Sciences; República Checa Fil: Eagling, Lawrence E.. The Queens University of Belfast; Irlanda Fil: Ferreira Rodríguez, Noé. Universidad de Vigo; España Fil: Hünicken, Leandro Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Johansson, Mattias L.. University of North Georgia; Estados Unidos Fil: Kregting, Louise. The Queens University of Belfast; Irlanda Fil: Labecka, Anna Maria. Jagiellonian University; Polonia Fil: Li, Deliang. Hunan Agricultural University; China Fil: Liquin, Florencia Fernanda. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina Fil: Marescaux, Jonathan. University of Namur; Bélgica. e-biom; Bélgica Fil: Morris, Todd J.. Fisheries and Ocean Canada; Canadá Fil: Nowakowska, Patrycja. University of Gdansk; Polonia Fil: Ozgo, Malgorzata. Kazimierz Wielki University; Polonia Fil: Paolucci, Esteban Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Peribáñez, Miguel A.. Universidad de Zaragoza; España Fil: Riccardi, Nicoletta. Consiglio Nazionale delle Ricerche; Italia Fil: Smith, Emily R. C.. University College London; Estados Unidos Fil: Sylvester, Francisco. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina

Freshwater bivalves are highly threatened and globally declining due to multiple anthropogenic impacts, making them important conservation targets. Because conservation policies and actions generally occur at the species level, accurate species identification and delimitation is critical. A recent phylogenetic study of Italian mussel populations revalidated an Anodonta species bringing the number of known European Anodontini from three to four species. The current study contributes to the clarification of the taxonomy and systematics of European Anodontini, using a combination of molecular, morphological and anatomical data, and constructs phylogenies based on complete mitogenomes. A redescription of A. exulcerata and a comparative analysis of morphological and anatomical characters with respect to the other two species of Anodonta present in the area are provided. No reliable diagnostic character has emerged from comparative analysis of the morphometric characters of 109 specimens from 16 sites across the Italian peninsula. In fact, the discriminant analysis resulted in a greater probability of correct assignment to the site of origin than to the species. This confirms the difficulties of an uncritical application of visual characters for the delimitation of species, especially for Anodontinae. This research was developed under ConBiomics: the missing approach for the conservation of freshwater bivalves project Nº NORTE-01-0145-FEDER-030286, cofinanced by COMPETE 2020, Portugal 2020 and the European Union through the ERDF - European Regional Development Fund and by FCT - Fundação para a Ciência e a Tecnologia, through national funds (UID/Multi/04423/2019). FCT also supported Manuel Lopes-Lima (SFRH/BD/115728/2016). info:eu-repo/semantics/publishedVersion

The study of the contamination of plastic mixtures sampled in natural environments is currently focused on their qualitative and quantitative assessment, while the evaluation of their effects on organisms is normally performed by experiments carried out at exposure conditions (size, shape, polymers) often far from the environmental ones. To improve the ecological realism, the aim of this study was to collect different plastic mixtures in 9 sampling stations located in 7 watercourses within the metropolitan city of Milan, one of the most anthropized and industrialized European areas, to evaluate both their qualitative and quantitative characteristics and, at the same time, to assess their ecotoxicological effects by exposing for 7 days some specimens of the freshwater bivalve Dreissena polymorpha to the mixtures collected in the sampling sites. The plastic characterization was performed by a Fourier-Transform Infrared spectrometer coupled with an optical microscope (μFT-IR), after several stages aimed to sample cleaning, separation of plastics and visual sorting. The possible effects caused by the plastic mixtures were carried out by the measurements of a biomarker suite to evaluate many cellular and molecular endpoints in mussel tissues. The main results showed a widespread and heterogeneous contamination of plastics in the entire metropolitan area, with contamination peaks found above all in the only two rivers of natural origin (Olona River and Lambro River) where comparable or higher values were reached than plastic concentrations measured in several European rivers. Despite this worrying contamination, the ecotoxicological data obtained after the exposures to the plastic mixtures collected in the selected water bodies showed only a mild effect on oxidative stress and on the variation of some antioxidant enzymes.

The adsorption of biomacromolecules is a fundamental process that can alter the behaviour and adverse effects of nanoparticles (NPs) in natural systems. While the interaction of NPs with natural molecules present in the environment has been described, their biological impacts are largely unknown. Therefore, this study aims to provide a first evidence of the influence of biomolecules sorption on the toxicity of cerium oxide nanoparticles (CeO2NPs) towards the freshwater bivalve Dreissena polymorpha. To this aim, we compared naked CeO2NPs and coated with alginate and chitosan, two polysaccharides abundant in aquatic environments. Mussels were exposed to the three CeO2NPs (naked, chitosan- and alginate-coated) up to 14 days at 100 μg L−1, which is a concentration higher than the environmental one predicted for this type of NP. A suite of biomarkers related to oxidative stress and energy metabolism was applied, and metabolomics was also carried out to identify metabolic pathways potentially targeted by CeO2NPs. Results showed that the coating with chitosan reduced NP aggregation and increased the stability in water. Nonetheless, the Ce accumulation in mussels was similar in all treatments. As for biological effects, all three types of CeO2NPs reduced significantly the level of reactive oxygen species and the activity of superoxide dismutase, glutathione peroxidase and glutathione-S-transferase. The effect was more pronounced in individuals exposed to CeO2NPs coated with alginate, which also significantly induced the activity of the electron transport system. Metabolomics analysis of amino acid metabolism showed modulation only in mussels treated with CeO2NPs coated with alginate. In this group, 25 metabolites belonging to nucleotides, lipids/sterols and organic osmolytes were also modulated, suggesting that the nanoparticles affect energetic metabolism and osmoregulation of mussels. This study highlights the key role of the interaction between nanoparticles and natural molecules as a driver of nanoparticle ecotoxicity.

The data that supports the findings of this study are available in the supplementary material of this article., Anthropogenic freshwater habitats may provide undervalued prospects for long-term conservation as part of species conservation planning. This fundamental, but overlooked, issue requires attention considering the pace that humans have been altering natural freshwater ecosystems and the accelerated levels of biodiversity decline in recent decades. We compiled 709 records of freshwater mussels (Bivalvia, Unionida) inhabiting a broad variety of anthropogenic habitat types (from small ponds to large reservoirs and canals) and reviewed their importance as refuges for this faunal group. Most records came from Europe and North America, with a clear dominance of canals and reservoirs. The dataset covered 228 species, including 34 threatened species on the IUCN Red List. We discuss the conservation importance and provide guidance on how these anthropogenic habitats could be managed to provide optimal conservation value to freshwater mussels. This review also shows that some of these habitats may function as ecological traps owing to conflicting management practices or because they act as a sink for some populations. Therefore, anthropogenic habitats should not be seen as a panacea to resolve conservation problems. More information is necessary to better understand the trade-offs between human use and the conservation of freshwater mussels (and other biota) within anthropogenic habitats, given the low number of quantitative studies and the strong biogeographic knowledge bias that persists., This publication is based upon work from COST Action CA18239, supported by COST (European Cooperation in Science and Technology). A.M.L. was financed by the Institute of Environmental Sciences Jagiellonian University (N18/DBS/000003) and K.N. by the Aragón Government. The authors acknowledge Jarosław Andrzejewski, Bartosz Czader, Anna Fica, Marcin Horbacz, Tomasz Jonderko, Steinar Kålås, Tomasz Kapela, Bjørn Mejdell Larsen, Maciej Pabijan, Katarzyna Pawlik, Ilona Popławska, Joanna Przybylska, Tomasz Przybył, Mateusz Rybak, Kjell Sandaas, Jarosław Słowikowski, Tomasz Szczasny, Michał Zawadzki and Paweł Zowada for providing detailed information on specific examples concerning freshwater mussels in anthropogenic habitats. We thank the editor and two anonymous referees for the valuable suggestions made, which increased the clarity of our manuscript.

Traditional detection of aquatic invasive species, via morphological identification is often time-consuming and can require a high level of taxonomic expertise, leading to delayed mitigation responses. Environmental DNA (eDNA) detection approaches of multiple species using Illumina-based sequencing technology have been used to overcome these hindrances, but sample processing is often lengthy. More recently, portable nanopore sequencing technology has become available, which has the potential to make molecular detection of invasive species more widely accessible and to substantially decrease sample turnaround times. However, nanopore-sequenced reads have a much higher error rate than those produced by Illumina platforms, which has so far hindered the adoption of this technology. We provide a detailed laboratory protocol and bioinformatic tools to increase the reliability of nanopore sequencing to detect invasive species, and we test its application using invasive bivalves. We sampled water from sites with pre-existing bivalve occurrence and abundance data, and contrasting bivalve communities, in Italy and Portugal. We extracted, amplified and sequenced eDNA with a turnaround of 3.5 days. The majority of processed reads were ≥ 99 % identical to reference sequences. There were no taxa detected other than those known to occur. The lack of detections of some species at some sites could be explained by their known low abundances. The approach is now being tested on other target taxa such as fish and other vertebrates.

An increasing threat to local, native freshwater mussels (Unionida)—an ecologically important but globally alarmingly declining group— is the invasion by exotic bivalves. The Enemy Release Hypothesis predicts that introduced species should benefit from enemy-mediated competition because they are less likely to be harmed by natural enemies, such as parasites, than their native competitors. We investigated within-site differences in parasitism between sympatric native (tot. five spp.) and invasive (tot. three spp.) bivalves in eight northern European waterbodies, which harboured totally 15 parasite taxa. In paired comparisons using within-site averages, the mean number of parasite species in the native bivalves was 2.3 times higher, and the sum of parasite prevalences 2.4 times higher, than in the invasive bivalves. This may lead to enemy-mediated compet- itive release of invaders and contribute to the success of invasive freshwater bivalves, in general. However, while the invasive clam Corbicula fluminea was completely free from parasites, parasite parameters of the other invader, Sinanodonta woodiana, were relatively high, indicating that the role of parasites can be invader-specific and urges further research. Under- standing the factors affecting success of freshwater bivalve invasions, such as parasitism, can aid invasion control and conservation of local, native (endangered) bivalves. Open access funding provided by University of Jyväskylä (JYU). Co-authors’ cooperation was initiated with the support of the Poznan ́ City Council under the ‘‘Academic and Scientific Poznan ́’’ Program. The study was funded by Estonian Ministry of Education and Research (institutional research funding project IUT 21-2 to Tiina Nõges) and by Estonian Research Council, Mobilitas Pluss research project MOBJD29. This study was also supported by the Polish Minister of Science and Higher Education, under the program ‘‘Regional Initiative of Excellence’’ in 2019–2022 (Grant No. 008/RID/2018/19), by Poznan ́ University of Life Sciences, University of Jyva ̈skyla ̈, and by CNR Short Term Mobility Project 2016. We thank Henryk Gierszal and Henn Timm for valuable assistance in field and laboratory. Open access funding provided by University of Jyväskylä (JYU). Co-authors’ cooperation was initiated with the support of the Poznan ́ City Council under the ‘‘Academic and Scientific Poznan ́’’ Program. The study was funded by Estonian Ministry of Education and Research (institutional research funding project IUT 21-2 to Tiina Nõges) and by Estonian Research Council, Mobilitas Pluss research project MOBJD29. This study was also supported by the Polish Minister of Science and Higher Education, under the program ‘‘Regional Initiative of Excellence’’ in 2019–2022 (Grant No. 008/RID/2018/19), by Poznan ́ University of Life Sciences, University of Jyva ̈skyla ̈, and by CNR Short Term Mobility Project 2016. We thank Henryk Gierszal and Henn Timm for valuable assistance in field and laboratory.

The identification of key biodiversity areas (KBA) was initiated by the International Union for Conservation of Nature in 2004 to overcome taxonomic biases in the selection of important areas for conservation, including freshwater ecosystems. Since then, several KBAs have been identified mainly based on the presence of trigger species (i.e., species that trigger either the vulnerability and or the irreplaceability criterion and thus identify a site as a KBA). However, to our knowledge, many of these KBAs have not been validated. Therefore, classical surveys of the taxa used to identify freshwater KBAs (fishes, molluscs, odonates, and aquatic plants) were conducted in Douro (Iberian Peninsula) and Sebou (Morocco) River basins in the Mediterranean Biodiversity Hotspot. Environmental DNA analyses were undertaken in the Moroccan KBAs. There was a mismatch between the supposed and actual presence of trigger species. None of the trigger species were found in 43% and 50% of all KBAs surveyed in the Douro and Sebou basins, respectively. Shortcomings of freshwater KBA identification relate to flawed or lack of distribution data for trigger species. This situation results from a misleading initial identification of KBAs based on poor (or even inaccurate) ecological information or due to increased human disturbance between initial KBA identification and the present. To improve identification of future freshwater KBAs, we suggest selecting trigger species with a more conservative approach; use of local expert knowledge and digital data (to assess habitat quality, species distribution, and potential threats); consideration of the subcatchment when delineating KBAs boundaries; thoughtful consideration of terrestrial special areas for conservation limits; and periodic field validation., La identificación de las áreas clave de biodiversidad (ACB) fue iniciada por la Unión Internacional para la Conservación de la Naturaleza en 2004 con el objetivo de sobreponerse a los sesgos taxonómicos en la selección de áreas importantes para la conservación, incluyendo los ecosistemas de agua dulce. Desde entonces, varias ACB han sido identificadas principalmente con base en la presencia de especies desencadenantes (es decir, especies que desencadenan el criterio de vulnerabilidad o de carácter irremplazable y por lo tanto identifican a un sitio como una ACB). Sin embargo, a nuestro conocimiento, muchas de estas ACB no han sido validadas. Por lo tanto, los censos clásicos de taxones utilizados para identificar las ACB de agua dulce (peces, moluscos, odonatos y plantas acuáticas) fueron realizados en las cuencas de los ríos Duero (Península Ibérica) y Sebou (Marruecos) en el Punto Caliente de Biodiversidad del Mediterráneo. Realizamos análisis de ADN ambiental en las ACB de Marruecos. Hubo una discrepancia entre la supuesta presencia y la actual presencia de especies desencadenantes. Ninguna de las especies desencadenantes se encontró en 43% y 50% de las ACB censadas en las cuencas del Duero y del Sebou, respectivamente. Las deficiencias en la identificación de las ACB de agua dulce están relacionadas con la carencia de datos o datos erróneos sobre la distribución de las especies desencadenantes. Esta situación resulta en una identificación inicial engañosa de las ACB con base en información ecológica deficiente (o incluso incorrecta) o también puede deberse al incremento en las perturbaciones humanas ocurridas entre la identificación de la ACB y el presente. Para mejorar la identificación de ACB de agua dulce en el futuro, sugerimos que la selección de especies desencadenantes se realice con un enfoque más conservador; que se usen el conocimiento local de los expertos y los datos digitales (para evaluar la calidad del hábitat, la distribución de las especies y las amenazas potenciales); que se consideren las subcuencas cuando se delimiten las fronteras de las ACB; que se consideren cuidadosamente las áreas de especies terrestres para los límites de conservación; y que se realicen validaciones periódicas de campo., Financial support was provided by the Portuguese Foun dation for Science and Technology (FCT) Grant to J.N. (2020.04637.BD). We thank the editor and 3 anonymous ref erees for the valuable suggestions made, which increased the clarity of our manuscript. This study was partially funded by the MAVA Foundation through the action plan Ensuring Integrated Resource Management in River Basins.

Through the Habitats Directive (92/43/EEC) and the financial investmentsof the LIFE projects, Europe has become an experimental arena for biologicalconservation. With an estimated annual budget ofEUR20 billion, the EU Biodi-versity Strategy for 2030 has set an ambitious goal of classifying 30% of itsland and sea territory as Protected Areas and ensuring no deterioration inconservation trends and the status of protected species. We analysed LIFEprojects focused on animals from 1992 to 2018 and found that investmentin vertebrates was six times higher than that for invertebrates (EUR970 versusEUR150 million), with birds and mammals alone accounting for 72% of speciesand 75% of the total budget. In relative terms, investment per speciestowards vertebrates has been 468 times higher than that for invertebrates.Using a trait-based approach, we show that conservation effort is primarilyexplained by species'popularity rather than extinction risk or body size.Therefore, we propose a roadmap to achieve unbiased conservation targetsfor 2030 and beyond.1. IntroductionOverwhelming evidence exists that most Earth ecosystem processes are beingaltered by human activities, suggesting that we may have entered a human-dominated geological epoch--the'Anthropocene'[1]. It is largely accepted thathumans are causing the sixth mass species extinction [2], which can be considereda clarion call to increase global efforts to study, halt, and possibly reverse theongoing negative environmental trends. Europe is no exception, given that it hasa long experience of human disturbance and consequent biodiversity loss [3]. Atthe same time, since the Habitats Directive (92/43/EEC) was established in 1992,the European Union (EU) has acted as a global test case for practical conservationand restoration of natural habitats and their wild flora and fauna.Although the Habitats Directive and the parallel financial investment on LIFEprojects--the EU flagship funding instrument for the environment and climate© 2020 The Authors. Published by the Royal Society under the terms of the Creative Commons AttributionLicense http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the originalauthor and source are credited.

Data supporting this study and R code to generate graphs and analyses are available in the Dryad Digital Repository: https://dx.doi.org/10.5061/dryad.1rn8pk0s0 [54]., Electronic supplementary material is available online at https://doi.org/10.6084/m9.figshare. c.5217460., Through the Habitats Directive (92/43/EEC) and the financial investments of the LIFE projects, Europe has become an experimental arena for biological conservation. With an estimated annual budget of €20 billion, the EU Biodi versity Strategy for 2030 has set an ambitious goal of classifying 30% of its land and sea territory as Protected Areas and ensuring no deterioration in conservation trends and the status of protected species. We analysed LIFE projects focused on animals from 1992 to 2018 and found that investment in vertebrates was six times higher than that for invertebrates (€970 versus €150 million), with birds and mammals alone accounting for 72% of species and 75% of the total budget. In relative terms, investment per species towards vertebrates has been 468 times higher than that for invertebrates. Using a trait-based approach, we show that conservation effort is primarily explained by species’ popularity rather than extinction risk or body size. Therefore, we propose a roadmap to achieve unbiased conservation targets for 2030 and beyond, R.C. is funded by the Helsinki Institute of Sustainability Science (HELSUS) and the University of Helsinki. S.M. is supported by the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 882221.

A protocol for the metabarcoding of DNA samples using nanopore technology, for the purposes of biomonitoring, biodiversity assessment, DNA-based diet analysis, or other related applications. The protocol is being used in our laboratory for detecting aquatic invasive bivalve species and for measuring biodiversity of fish and other vertebrates from water eDNA samples, as well as for species identification of scats. The key steps are a first PCR to amplify metabarcoding fragments, a 2nd PCR to add indexes (barcodes) to allow pooling of multiple samples, and the preparation of the pool for sequencing on a MinION sequencer. The protocol is adapted from PCR barcoding (96) amplicons (SQK-LSK109) by Nanopore.

Traditional detection of aquatic invasive species, via morphological identification is often time-consuming and can require a high level of taxonomic expertise, leading to delayed mitigation responses. Environmental DNA (eDNA) detection approaches of multiple species using Illumina-based sequencing technology have been used to overcome these hindrances, but sample processing is often lengthy. More recently, portable nanopore sequencing technology has become available, which has the potential to make molecular detection of invasive species more widely accessible and to substantially decrease sample turnaround times. However, nanopore-sequenced reads have a much higher error rate than those produced by Illumina platforms, which has so far hindered the adoption of this technology. We provide a detailed laboratory protocol and bioinformatic tools to increase the reliability of nanopore sequencing to detect invasive species, and we test its application using invasive bivalves. We sampled water from sites with pre-existing bivalve occurrence and abundance data, and contrasting bivalve communities, in Italy and Portugal. We extracted, amplified and sequenced eDNA with a turnaround of 3.5 days. The majority of processed reads were ≥ 99 % identical to reference sequences. There were no taxa detected other than those known to occur. The lack of detections of some species at some sites could be explained by their known low abundances. This is the first reported use of MinION to detect aquatic invasive species from eDNA samples. The approach can be easily adapted for other metabarcoding applications, such as biodiversity assessment, ecosystem health assessment and diet studies.

So far in Poland, the Asian clam Corbicula fluminea has been reported from the Oder (Odra) and Vistula River. Its new population has been discovered in the Warta-Gop?o Canal in Konin (central Poland), where water temperature can reach 34°C, as the canal is a part of a power plant lake cooling system. The spatial distribution of C. fluminea was found to be very uneven and that is probably why this species was not found during earlier research. The highest density of C. fluminea was 78 ind.·m-2 at the site where water flow was the fastest (2.49 m·s-1), providing sufficient oxygenation of the water. The results suggest that existing information about the distribution of C. fluminea may be far from complete because the clam can be present also in the habitats that were not regarded as suitable for the species according to earlier reports, and therefore have not been monitored for its presence.

Eutrophication still is one of the greatest anthropogenic impacts affecting aquatic ecosystems. Food web manipulations to reverse eutrophic conditions have been applied, mainly by reducing fish stocks. However, the long-term results of biomanipulation are still ambiguous. The objective of this study was to evaluate biomanipulation effects on zooplankton functional diversity and production during 24 years of monitoring a shallow temperate lake. Temporal variation in crustacean biomass (CB), zooplankton resource use efficiency (RUE), limnological variables, functional diversity indices and functional traits were assessed using the Mann–Kendall test. The effects of the limnological and functional variables on zooplankton production (CB and RUE) were analyzed by generalized least squares models (GLSs). We found decreasing trends for almost all the limnological variables, indicating a reduction in lake eutrophic conditions. We also observed a decreasing trend in functional traits related to pelagic habitat, filter-feeding mode, herbivore feeding preference and body size. The GLS results showed that functional dispersion and chlorophyll a are important determinants of zooplankton production. The effects of fish biomanipulation produced no significant temporal trends in zooplankton biomass. In fact, the increase in submerged macrophytes promoted littoral food webs, which was likely the main determining factor of the changes in zooplankton functional traits and production.

We report for the first time that the freshwater mussel Microcondylaea bonellii (Ferussac, 1827) functions as a suitable host for the European bitterling Rhodeus amarus (Bloch, 1782). Given the recent expansion of R. amarus in Europe, the possible physiological cost (e.g. competition for oxygen, reduction in water circulation, and consequent impairment of filter-feeding) of this interaction may further affect the already poor conservation status of M. bonellii populations., We acknowledge the two anonymous referees for the helpful suggestions that improve the clarity of our manuscript. This research was funded by FCT under project ConBiomics No NORTE-01-0145-FEDER-030286, cofinanced by COMPETE 2020, Portugal 2020 and the European Union through the ERDF.

Using a new fossil-calibrated mitogenome-based approach, we identified macroevolutionary shifts in mitochondrial gene order among the freshwater mussels (Unionoidea). We show that the early Mesozoic divergence of the two Unionoidea clades, Margaritiferidae and Unionidae, was accompanied by a synchronous split in the gene arrangement in the female mitogenome (i.e., gene orders MF1 and UF1). Our results suggest that this macroevolutionary jump was completed within a relatively short time interval (95% HPD 201–226 Ma) that coincided with the Triassic–Jurassic mass extinction. Both gene orders have persisted within these clades for ~200 Ma. The monophyly of the so-called “problematic” Gonideinae taxa was supported by all the inferred phylogenies in this study using, for the first time, the M- and F-type mitogenomes either singly or combined. Within Gonideinae, two additional splits in the gene order (UF1 to UF2, UF2 to UF3) occurred in the Mesozoic and have persisted for ~150 and ~100 Ma, respectively. Finally, the mitogenomic results suggest ancient connections between freshwater basins of East Asia and Europe near the Cretaceous–Paleogene boundary, probably via a continuous paleo-river system or along the Tethys coastal line, which are well supported by at least three independent but almost synchronous divergence events., The authors wish to thank the Editor and the three anonymous reviewers for helpful remarks and suggestions that improved the quality of the manuscript. This research was developed under ConBiomics: the missing approach for the Conservation of freshwater Bivalves Project No NORTE-01-0145-FEDER-030286, cofinanced by COMPETE 2020, Portugal 2020 and the European Union through the ERDF, and by FCT through national funds (UID/Multi/04423/2019). FCT also supported MLL (SFRH/BD/115728/2016). The Russian Ministry of Education and Science (project no. 6.2343.2017/4.6), the Federal Agency for Scientific Organizations (project no. 0409-2015-0143), the Presidium of the Russian Academy of Sciences (scientific program no. 52), and the Russian Foundation for Basic Research, RFBR (project no. 17-45-290066) supported INB. Permits for fieldwork and sampling in Malaysia were issued by the Malaysian Ministry of Higher Education (FRGS/1/2015/WAB13/UNIM//1).

Freshwater mussels are declining globally, and effective conservation requires prioritizing research and actions to identify and mitigate threats impacting mussel species. Conservation priorities vary widely, ranging from preventing imminent extinction to maintaining abundant populations. Here, we develop a portfolio of priority research topics for freshwater mussel conservation assessment. To address these topics, we group research priorities into two categories: intrinsic or extrinsic factors. Intrinsic factors are indicators of organismal or population status, while extrinsic factors encompass environmental variables and threats. An understanding of intrinsic factors is useful in monitoring, and of extrinsic factors are important to understand ongoing and potential impacts on conservation status. This dual approach can guide conservation status assessments prior to the establishment of priority species and implementation of conservation management actions., La lista completa de autores de este trabajo puede verse en el archivo asociado., Facultad de Ciencias Naturales y Museo

Corbicula fluminea and Dreissena polymorpha are two non-indigenous species (NIS), known to provoke biodiversity loss of the existent native communities and alterations in the ecosystem functioning structure. Both of these NIS have successfully founded well established populations in Lakes Maggiore and Garda (Northern Italy). Here, we evaluated the mitochondrial COI genetic diversity of C. fluminea and D. polymorpha populations from the aforementioned lakes. The COI gene analysis revealed one C. fluminea haplotype, belonging to the FW5 androgenetic invasive lineage. Two D. polymorpha haplotypes – LM1 and LM2 – were detected in Lake Maggiore. The D. polymorpha comparative phylogeographical haplotype analysis between Lake Maggiore and the retrieved COI data available from Lake Garda revealed that LM1 is the dominant haplotype in both populations, whereas LM2 a rare haplotype was only detected in Lake Maggiore. These findings contribute for a better understanding of the demographic history of these highly invasive species in these Italian lakes, thus suggesting that C. fluminea and D. polymorpha populations present a similar genetic pattern. The low genetic diversity detected in both of these bivalve populations seems to reflect a pre-existent low genetic pool prevenient from the introductory source(s).

The long scientific way of Dr. Oscar Ravera started soon after the Second World War and lasted for more than 60 years. A vast number of his research projects covered practically all main fields in limnology of the twentieth century.

Freshwater mussels of the Order Unionida provide important ecosystem functions and services, yet many of their populations are in decline. We comprehensively review the status of the 16 currently recognized species in Europe, collating for the first time their life-history traits, distribution, conservation status, habitat preferences, and main threats in order to suggest future management actions. In northern, central, and eastern Europe, a relatively homogeneous species composition is found in most basins. In southern Europe, despite the lower species richness, spatially restricted species make these basins a high conservation priority. Information on freshwater mussels in Europe is unevenly distributed with considerable differences in data quality and quantity among countries and species. To make conservation more effective in the future, we suggest greater international cooperation using standardized protocols and methods to monitor and manage European freshwater mussel diversity. Such an approach will not only help conserve this vulnerable group but also, through the protection of these important organisms, will offer wider benefits to freshwater ecosystems.

Freshwater mussels of the family Unionidae are one of the most threatened groups worldwide and have suffered severe decline over recent decades. Although the freshwater duck mussel, Anodonta anatina (Linnaeus, 1758), is still widespread, this species has shown evidence of recent declines and is already protected in some European countries. Informed conservation efforts must take into account patterns in genetic diversity and phylogeography. In the present study, 20 newly developed polymorphic loci were described and tested in seven populations of A. anatina, belonging to three previously detected divergent mtDNA lineages. The genetic diversity patterns, within and among A. anatina populations, were evaluated to test their congruence with those lineages. A high genetic differentiation (FST) was found among all populations, with the exception of those in Central Europe (Germany) and the UK, which were not strongly structured. The present study confirms the division of the species into three evolutionarily significant units corresponding to the three previously detected mtDNA lineages, which should be managed independently. Furthermore, owing to the high differentiation among southern European populations, the establishment of distinct management units for the Guadalquivir, Guadiana and Douro populations in the Iberian Peninsula is also proposed. Copyright © 2015 John Wiley & Sons, Ltd.

Conservation of freshwater mollusks is essential to maintain the important ecosystem functions and services they provide. Nonetheless, they are at risk as evidenced by their rapid and extensive global decline due to multiple causes, mainly of anthropic origin. Conservation strategies to stop this negative trend and maximize current biodiversity are urgently needed but are hampered by the lack of key information. Although in recent decades there have been an increasing number of studies on the ecology and conservation of these animals, the integration of knowledge acquired by different research groups is a key step for improving our efforts. Such integration would also help policy makers establish guidelines, which can be applied in conservation management of these animals and their natural habitats. The Freshwater Mollusk Conservation Society (FMCS) can be a reference for everyone but, to date, the Society is primarily serving members in the United States and Canada. This recognition prompted the idea of expanding the Society's role on other continents, starting in Europe. Europe has been chosen because of the large number of active freshwater malacologists working in a number of countries. The organization of a FMCS Meeting outside of North America aims to expand the membership, share research and data with international colleagues, and foster wider collaboration. It is under this perspective that this event was organized this time in Italy - hopefully, the first of a series of FMCS-sponsored international meetings. The goals of this first international meeting are: 1. To start bringing together international experts in the biology and conservation of freshwater mollusks that will create a network of knowledge with the final goal of developing collaborative projects and, eventually, global directives for the protection and conservation of this important faunal group. 2. To provide, with this first step, an incentive for non-North American freshwater malacologists to become members of FMCS and participate in planned activities, Symposia, publications, and Workshops. 3. To start organizing local malacologists -- e.g. initially from Europe, but to be expanded to other continents around the world -- to provide structure and communication about resources, questions, advocacy, and collaboration. This will facilitate developing techniques to address similar problems encountered across freshwater molluscan research. 4. To start holding international meetings focused on all freshwater mollusks around the world. The two recent international freshwater bivalve meetings (Bragança, Portugal in 2012 and Buffalo, New York in 2015) were both exciting and fun with good participation. With this 2018 meeting in Europe, we want to start building an international network that includes all freshwater mollusks. In this context we would like to express our appreciation to our sponsors and organizing institutions and our gratitude to keynote speakers, authors, session chairpersons and all attendees whose contribution have made the meeting a success. We are honored to host you at the 1st FMCS Europe conference in Verbania, Italy.