45 research outputs found
Patterns in species richness and endemismof European freshwater fish
Aim
To analyse the patterns in species richness and endemism of the native
European riverine fish fauna, in the light of the Messinian salinity crisis and the Last
Glacial Maximum (LGM).
Location
European continent.
Methods
After gathering native fish faunistic lists of 406 hydrographical networks,
we defined large biogeographical regions with homogenous fish fauna, based on a
hierarchical cluster analysis. Then we analysed and compared the patterns in species
richness and endemism among these regions, as well as speciesâarea relationships.
Results
Among the 233 native species present in the data set, the Cyprinidae family
was strongly dominant (> 50% of the total number of species). Seven biogeographical
regions were defined: Western Peri-Mediterranea, Central Peri-Mediterranea,
Eastern Peri-Mediterranea, Ponto-Caspian Europe, Northern Europe, Central Europe
and Western Europe. The highest regional species richness was observed for Central
Peri-Mediterranea and Ponto-Caspian Europe. The highest endemic richness was
found in Central Peri-Mediterranea. Speciesâarea relationships were characterized by
high slope values for Peri-Mediterranean Europe and low values for Central and
Western Europe.
Main conclusions
The results were in agreement with the âLago Mareâ hypothesis
explaining the specificity of Peri-Mediterranean fish fauna, as well as with the history
of recolonization of Central and Western Europe from Ponto-Caspian Europe
following the LGM. The results also agreed with the mechanisms of speciation and
extinction influencing fish diversity in hydrographical networks. We advise the use
of the seven biogeographical regions for further studies, and suggest considering
Peri-Mediterranean Europe and Ponto-Caspian Europe as âbiodiversity hotspotsâ for
European riverine fish
Implementation options for DNA-based identification into ecological status assessment under the European Water Framework Directive
Assessment of ecological status for the European Water Framework Directive (WFD) is based on âBiological Quality Elementsâ (BQEs), namely phytoplankton, benthic flora, benthic invertebrates and fish. Morphological identification of these organisms is a time-consuming and expensive procedure. Here, we assess the options for complementing and, perhaps, replacing morphological identification with procedures using eDNA, metabarcoding or similar approaches. We rate the applicability of DNA-based identification for the individual BQEs and water categories (rivers, lakes, transitional and coastal waters) against eleven criteria, summarised under the headlines representativeness (for example suitability of current sampling methods for DNA-based identification, errors from DNA-based species detection), sensitivity (for example capability to detect sensitive taxa, unassigned reads), precision of DNA-based identification (knowledge about uncertainty), comparability with conventional approaches (for example sensitivity of metrics to differences in DNA-based identification), cost effectiveness and environmental impact. Overall, suitability of DNA-based identification is particularly high for fish, as eDNA is a well-suited sampling approach which can replace expensive and potentially harmful methods such as gill-netting, trawling or electrofishing. Furthermore, there are attempts to replace absolute by relative abundance in metric calculations. For invertebrates and phytobenthos, the main challenges include the modification of indices and completing barcode libraries. For phytoplankton, the barcode libraries are even more problematic, due to the high taxonomic diversity in plankton samples. If current assessment concepts are kept, DNA-based identification is least appropriate for macrophytes (rivers, lakes) and angiosperms/macroalgae (transitional and coastal waters), which are surveyed rather than sampled. We discuss general implications of implementing DNA-based identification into standard ecological assessment, in particular considering any adaptations to the WFD that may be required to facilitate the transition to molecular data
Why we need sustainable networks bridging countries, disciplines, cultures and generations for Aquatic Biomonitoring 2.0: A Perspective Derived From the DNAqua-Net COST Action
Aquatic biomonitoring has become an essential task in Europe and many other regions as a consequence of strong anthropogenic pressures affecting the health of lakes, rivers, oceans and groundwater. A typical assessment of the environmental quality status, such as it is required by European but also North American and other legislation, relies on matching the composition of assemblages of organisms identified using morphological criteria present in aquatic ecosystems to those expected in the absence of anthropogenic pressures. Through decade-long and difficult intercalibration exercises among networks of regulators and scientists in European countries, a pragmatic biomonitoring approach was developed and adopted, which now produces invaluable information. Nonetheless, this approach is based on several hundred different protocols, making it susceptible to issues with comparability, scale and resolution. Furthermore, data acquisition is often slow due to a lack of taxonomic experts for many taxa and regions and time-consuming morphological identification of organisms. High-throughput genetic screening methods such as (e)DNA metabarcoding have been proposed as a possible solution to these shortcomings. Such "next-generation biomonitoring", also termed "biomonitoring 2.0", has many advantages over the traditional approach in terms of speed, comparability and costs. It also creates the potential to include new bioindicators and thereby further improves the assessment of aquatic ecosystem health. However, several major conceptual and technological challenges still hinder its implementation into legal and regulatory frameworks. Academic scientists sometimes tend to overlook legal or socioeconomic constraints, which regulators have to consider on a regular basis. Moreover, quantification of species abundance or biomass remains a significant bottleneck to releasing the full potential of these approaches. Here, we highlight the main challenges for next-generation aquatic biomonitoring and outline principles and good practicCOST - European Cooperation in Science and Technology(CA15219). COST Action DNAqua-Net (CA15219), supported by the COST (European Cooperation in Science and Technology) programm
Variabilité spatio-temporelle de la transition salmoniformes-cypriniformes dans la Garonne
TOULOUSE-ENSAT-Documentation (315552324) / SudocSudocFranceF
Les interactions scientifiques-gestionnaires dans le domaine de lâĂ©cologie aquatique : exemple de la mise en eÂœuvre de la DCE
International audienceDirective donnant un cadre Ă la politique de lâeau Ă lâĂ©chelle europĂ©enne, la DCE a fixĂ© des objectifs ambitieux pour la prĂ©servation et la restauration de lâĂ©tat des eaux superficielles et souterraines. Elle a pour objectif lâatteinte en 2015 du « bon Ă©tat » de lâensemble des masses dâeau, pour la mĂ©tropole comme pour les dĂ©partements dâoutre-mer. La DCE impose aux Ătats membres des exigences radicalement nouvelles en termes de prise en compte des diffĂ©rents compartiments biologiques et de fiabilitĂ© Ă atteindre dans lâĂ©valuation de lâĂ©tat Ă©cologique. Lâannexe V de la directive demande en particulier aux Ătats membres de mettre au point, pour chaque catĂ©gorie de masses dâeau superficielles (cours dâeau, plans dâeau, estuaires et lagunes, eaux cĂŽtiĂšres), un outil de bioindication DCE-compatible pour chacun des Ă©lĂ©ments de qualitĂ© biologiques (EQB) mentionnĂ©s dans la DCE (phytobenthos, phytoplancton, macrophytes, invertĂ©brĂ©s benthiques, poissons). Ce sont donc plus de 50 outils de bioindication (incluant les dĂ©partements dâoutre-mer) quâil convient de dĂ©velopper et de mettre en Âœoeuvre pour rĂ©pondre aux exigences de la directive. Ces exigences se sont traduites par un effort sans prĂ©cĂ©dent pour le dĂ©veloppement de mĂ©thodes de bioindication. Pour les organismes de recherche chargĂ©s de la mise au point de ces mĂ©thodes, lâenjeu est double : il sâagit bien sĂ»r de construire, ex nihilo ou sur la base de mĂ©thodes prĂ©existantes, des outils de bioindication pertinents au plan scientifique et adaptĂ©s Ă une mise en oeÂœuvre Ă grande Ă©chelle, mais aussi dâassurer la compatibilitĂ© de ces mĂ©thodes avec le cadre prĂ©cis imposĂ© par la DCE : normalisation des protocoles, inter-Ă©talonnage avec les mĂ©thodes des autres Ă©tats-membres europĂ©ens, intĂ©gration dans des rĂšgles dâĂ©valuation en gardant une indispensable cohĂ©rence hydroĂ©cologique, construire les processus de leur mise en oeÂœuvre en routine par les opĂ©rateurs des rĂ©seaux de surveillance. Ce processus, lourd et complexe, a nĂ©cessitĂ© une collaboration accrue entre porteurs des politiques publiques, gestionnaires des milieux aquatiques et dĂ©veloppeurs scientifiques au cours des 10 derniĂšres annĂ©es, en vue du prochain cycle de la DCE (2016-2021). Cette communication vise Ă rappeler les modalitĂ©s de concertation et dâimplication des diffĂ©rents acteurs impliquĂ©s et Ă dĂ©battre des opportunitĂ©s crĂ©Ă©es, mais aussi des difficultĂ©s rencontrĂ©es et des voies dâamĂ©lioration potentielles pour une mise en oeÂœuvre optimale de la DCE en France
Répartition des écrevisses à pattes blanches, Austropotamobius pallipes (Lereboullet, 1858) dans trois ruisseaux de CorrÚze ; observation particuliÚre des juvéniles
National audienceThe use of three capture methods (Surber sampling, electric fishing and night-hand capture) allowed the analysis of differential habitat usage by the white-clawed crayfish Austropotamobius pallipes in three brooks of CorrĂšze - France. Among these methods, the best one for studying juveniles habitat was Surber sampling, which allowed the capture of 536 individuals. This study showed that, during daytime, most of the adults occurred in branks with crevices or roots, areas of pebbles or boulders, those with a high macrophytic covering and also in logs, while they were preferentially found in areas of gravels, pebbles and boulders during their nocturnal movements. The young of the year were caught especially among pebbles, boulders, macrophytes and river banks with rootlets. In some cases, the reduction or disappearance of one habitat which is particularly favourable to the young of the year might be compensated by a more active colonization of some habitats which normally shelter only a few crayfish.L'habitat prĂ©fĂ©rentiel des Ă©crevisses Ă pattes blanches Austropotamobius pallipes a Ă©tĂ© analysĂ© dans trois cours d'eau de CorrĂšze, grĂące Ă la combinaison de trois mĂ©thodes de capture ( pĂȘche au filet de type Surber, pĂȘche Ă©lectrique et pĂȘche Ă la main de nuit). Parmi ces mĂ©thodes, la plus efficace pour la capture des juvĂ©niles s'est avĂ©rĂ©e ĂȘtre le filet de type Surber, qui a permis la capture de 536 individus. Suite Ă cette Ă©tude, il apparaĂźt que les Ă©crevisses adultes recherchent de prĂ©fĂ©rence les berges constituĂ©es de racines ou avec des cavitĂ©s, des blocs, les galets, la vĂ©gĂ©tation aquatique et les souches pour s'abriter durant le jour, tandis qu'elles frĂ©quentent prĂ©fĂ©rentiellement les graviers, les galets et les blocs pendant leurs dĂ©placements nocturnes. Les juvĂ©niles s'abritent de prĂ©fĂ©rence dans les galets, les blocs, les vĂ©gĂ©taux aquatiques et les berges composĂ©es d'amas de radicelles. Dans certains cas, la rĂ©duction, voire la disparition d'un habitat particuliĂšrement favorable aux juvĂ©niles peut ĂȘtre compensĂ©e par une colonisation plus importante d'autres habitats habituellement dĂ©laissĂ©s
Life-history variation in freshwater fish: an assessment of the `opportunistic-equilibrium-periodic' triangular model
International audienceno abstrac
Réseau de suivi des opérations de restauration hydromorphologique en cours d'eau : les Sites de démonstration
National audienceLes cours d'eau, dont l'hydromorphologie est historiquement fortement impactée par les activités anthropiques (rectifications, extractions et curages, mise en place de seuils, endiguements, etc.), font aujourd'hui l'objet de mesures d'atténuation et de restauration. Depuis une dizaine d'années en particulier, la restauration hydromorphologique en cours d'eau connaßt un essor important, grùce à l'impulsion de différentes politiques publiques ; elle est notamment considérée comme un levier d'action majeur par la DCE. Il s'agit par exemple de reméandrer un cours d'eau historiquement rectifié, d'effacer un ouvrage, ou de recharger le fond du lit présentant un déficit en sédiments. Afin d'évaluer l'efficacité de ces opérations, des suivis sont parfois mis en oeuvre. Cependant, la difficulté à mobiliser et associer opérateurs de terrain, maßtres d'ouvrages, financeurs, et scientifiques, est souvent à l'origine de suivis hétérogÚnes et trop limités dans le temps. Afin de remédier à ces lacunes, depuis 2010, l'Onema, aujourd'hui intégré à l'Agence française pour la biodiversité, l'Irstea et les Agences de l'eau, constituent un réseau de Sites de démonstration pour la restauration hydromorphologique des cours d'eau. Le réseau des Sites de démonstration vise à combler les manques en termes de connaissances sur les effets des opérations de restauration des cours d'eau en préconisant un suivi standardisé, rigoureux et reproductible sur des sites répartis sur l'ensemble du territoire national. à terme, ce réseau a pour finalité de mieux connaßtre les réajustements physiques et la dynamique de recolonisation des communautés suite à une opération de restauration d'un type donné. Il permettra également d'alimenter les retours d'expérience sur les travaux mis en oeuvre. Le réseau des Sites de démonstration est également un outil de communication auprÚs des gestionnaires, des maßtres d'ouvrage et du grand public. La possibilité d'étendre ce type de réseau à d'autres milieux (plans d'eau, puis milieux humides) est également à l'étude
Effects of temperature on biological and biochemical indicators of the life-history strategy of bullhead Cottus gobio
International audienceThe biological and biochemical effects of temperature on life-history strategy of female bullhead Cottus gobio were investigated. Fish from two populations (Bez Basin, south-east France) experiencing contrasted thermal environments (i.e. more or less stable) were reared during 4 months at three distinct temperatures (7, 9 or 12° C). Both somatic (soma fresh mass and muscle triglyceride content) and reproductive (gonad fresh mass, fecundity, mean diameter of eggs and gonad triglyceride content) indicators were examined. Mixed models indicated that an increasing temperature had significant negative effects on all life-history indicators except for soma fresh mass. Differences in life-history strategy with regard to muscle and gonad triglyceride contents, however, suggest that populations experiencing more variable thermal environments may be better adapted than others to cope with an increasing temperature. These findings may have important implications for C. gobio populations, within the context of climate warming
Méta-analyse de l'impact des centrales photovoltaïques sur les communautés végétales
In the current context of global warming, photovoltaic installations are set to expand rapidly, particularly in France, where the government aims to triple installed solar power capacity by 2030. Although photovoltaic panels theoretically help to limit our greenhouse gas emissions, they can nevertheless have an impact on natural species and ecosystems. In this context, PatriNat (OFB-MNHN-CNRS-IRD) has carried out a systematic mapping exercise with the aim of compiling the available literature on the effects of photovoltaic installations on wild terrestrial and semi-aquatic species. This work enabled the identification of a greater body of knowledge concerning the effects of photovoltaic installations on plant communities, for which a synthesis of quantitative results could be envisaged. The aim of this summary was to determine the effect of the presence of photovoltaic installations on the abundance, biomass and diversity of plant communities evolving within photovoltaic installations.Our results showed a statistically significant reduction in plant diversity under the panels compared with the inter-row. However, no statistically significant effect of the panels was found on plant abundance. At present, given the small amount of data available that can be analysed, our results remain partial. We therefore recommend that our analyses be updated rapidly, particularly in view of the highly heterogeneous nature of the effects of photovoltaic installations identified in the literature to date.Dans le contexte actuel de rĂ©chauffement climatique, les installations photovoltaĂŻques sont amenĂ©es Ă rapidement se dĂ©velopper, et notamment en France oĂč le gouvernement ambitionne de tripler la puissance installĂ©e en Ă©nergie solaire dâici 2030. Bien que permettant en thĂ©orie de limiter nos Ă©missions de gaz Ă effet de serre, les panneaux photovoltaĂŻques peuvent avoir des impacts sur les espĂšces et Ă©cosystĂšmes naturels. Dans ce contexte, PatriNat (OFBâMNHNâCNRSâIRD) a menĂ© un travail de carte systĂ©matique ayant pour objectif de recenser la littĂ©rature disponible concernant les effets des installations photovoltaĂŻques sur les espĂšces sauvages terrestres et semi-aquatiques. Ce travail a permis dâidentifier une connaissance plus fournie concernant les effets des installations photovoltaĂŻques sur les communautĂ©s vĂ©gĂ©tales et pour laquelle une synthĂšse de rĂ©sultats quantitatifs Ă©tait envisageable. Cette synthĂšse a donc eu pour but de dĂ©terminer lâeffet de la prĂ©sence des installations photovoltaĂŻques sur lâabondance, la biomasse et la diversitĂ© des communautĂ©s vĂ©gĂ©tales Ă©voluant au sein des installations photovoltaĂŻques.Nos rĂ©sultats ont mis en Ă©vidence une diminution statistiquement significative de la diversitĂ© floristique sous les panneaux par rapport Ă lâinter-rang. Aucun effet statistiquement significatif des panneaux nâa, en revanche, Ă©tĂ© mis en Ă©vidence sur lâabondance vĂ©gĂ©tale. En lâĂ©tat actuel, au vu de la faible quantitĂ© de donnĂ©es disponibles et analysables, nos rĂ©sultats restent partiels. Nous recommandons donc que nos analyses soient mises Ă jour rapidement et ce notamment, au vu de la forte hĂ©tĂ©rogĂ©nĂ©itĂ© des effets des installations photovoltaĂŻques identifiĂ©s jusquâĂ prĂ©sent dans la littĂ©rature