Alien Fish Species in France with Emphasis on the Recent Invasion of Gobies

Introduction of alien species constitutes worldwide one of the major threats to biodiversity, particularly in freshwater ecosystems. In France, the number of alien aquatic plant and animal species has increased exponentially over time in freshwater ecosystems and shows no sign of decreasing. For fish only, more than 40 alien species have been either voluntary or involuntary introduced in the past decades. About two-thirds are still present today and at least 26 are naturalized. As in many European countries, the fish introduction history in France switched from voluntary introduction in the nineteenth century (aquaculture, sport fishing, and management of ecosystems) to unintentional but human-aided introductions (aquarium trade and global ship transport). The negative impacts of alien species on native species and ecosystems are most often unknown in France and needs further studies to develop a functional policy on alien species introductions and the protection of aquatic ecosystems integrity. The information gathered allow discussing the possible reasons explaining whether an alien species is able or not to establish sustainable populations in France and thereafter became invasive, such as gobies recently arrived

Sympatric Dreissena species in the Meuse River : towards a dominance shift from zebra to quagga mussels

The rapid spread of the quagga mussel, Dreissena rostriformis, in Western Europe is of particular concern since the species is known to have serious ecological and economic impacts, similar to those of the well-established zebra mussel, Dreissena polymorpha. This study aimed (1) to provide an update on the quagga mussel distribution in several Belgian inland waterways, and (2) to check if a shift in dominance between Dreissena species is occurring. Using density measurements and artificial substrate samplers, we compared population dynamics for both species at different time-points based on size-frequency distribution. Our results show that quagga mussels are spreading rapidly throughout Belgium via a number of possible invasion fronts based around large rivers and canals. The quagga mussel became the dominant dreissenid species in both the Meuse River and a number of Belgian canals. In just three years, quagga mussel’s relative abundance increased from 2.9% (±2.9) to 52.6% (±43.1) of the total dreissenid population in the Meuse River. The most rapid increase in abundance has occurred in the Albert Canal, where quagga mussels achieved a mean relative abundance of 80% two years after the first observation. In the Meuse River, the quagga mussel displays a faster growth rate and/or earlier reproduction than the zebra mussel. We discuss different mechanisms that could explain the quagga mussel’s apparent competitive advantage over the zebra mussel

Διακύμανση στην καμπύλη ροής-όγκου και των σπιρομετρικών παραμέτρων απο την παρεμβολή (αντιμικροβιακού φίλτρου) σε φορητό και σταθερό σπιρόμετρο με πνευματοταχογράφο σε ενήλικα ασυμπτωματικό πληθυσμό και σε πληθυσμό με αποφρακτική ή περιοριστική συνδρομή.

<p>A: total lipid content (mg.mL⁻¹). B: glycogen content (µg.mg⁻¹ tissue). Error bar represent mean ± SE. Different letters above the bars indicate significantly different values (Tukey's HSD test, <i>p</i>-values<0.05).</p

Behavioural and Physiological Responses of Gammarus pulex Exposed to Cadmium and Arsenate at Three Temperatures: Individual and Combined Effects

This study aimed at investigating both the individual and combined effects of cadmium (Cd) and arsenate (AsV) on the physiology and behaviour of the Crustacean Gammarus pulex at three temperatures (5, 10 and15°C). G. pulex was exposed during 96 h to (i) two [Cd] alone, (ii) two [AsV] alone, and (iii) four combinations of [Cd] and [AsV] to obtain a complete factorial plane. After exposure, survival, [AsV] or [Cd] in body tissues, behavioural (ventilatory and locomotor activities) and physiological responses (iono-regulation of [Na+] and [Cl−] in haemolymph) were examined. The interactive effects (antagonistic, additive or synergistic) of binary mixtures were evaluated for each tested temperature using a predictive model for the theoretically expected interactive effect of chemicals. In single metal exposure, both the internal metal concentration in body tissues and the mortality rate increased along metallic gradient concentration. Cd alone significantly impaired both [Na+] and [Cl−] while AsV alone had a weak impact only on [Cl−]. The behavioural responses of G. pulex declined with increasing metal concentration suggesting a reallocation of energy from behavioural responses to maintenance functions. The interaction between AsV and Cd was considered as ‘additive’ for all the tested binary mixtures and temperatures (except for the lowest combination at 10°C considered as “antagonistic”). In binary mixtures, the decrease in both ventilatory and locomotor activities and the decline in haemolymphatic [Cl−] were amplified when respectively compared to those observed with the same concentrations of AsV or Cd alone. However, the presence of AsV decreased the haemolymphatic [Na+] loss when G. pulex was exposed to the lowest Cd concentration. Finally, the observed physiological and behavioural effects (except ventilation) in G. pulex exposed to AsV and/or Cd were exacerbated under the highest temperature. The discussion encompasses both the toxicity mechanisms of these metals and their interaction with rising temperature

Microrépartition des invertébrés benthiques en eau courante : caractéristiques des microhabitats et organisation de leurs peuplements

The aim of this is to examine and to understand more accurately (1) the invertebrate communities organization into the different microhabitats of a river bottom, and (2) environmental factors which affect the organization of these communities. A separate sampling of microhabitats was realized on spring and autumn 1993 and 1994 in 12 stations. Community structure was summarized with biocenotic indices for which we have specify the main performances. Simulations allowed us to consider that the mesological traits of the sampled microhabitats influence strongly the appraisal of the study-site community structure, principally because invertebrates display an aggregate distribution. The study of microdistribution factors show that "substrate type", "current velocity" and, to a less extent, "water death" are of primary importance for the organization of microhabitat communities. These mesological traits focus in fact on three ecological characteristics of the habitat :(1) its capacity to offer a great variety of ecological niches for macroinvertebrates, (2) its trophic potentialities and (3) its temporal stability, which respectively determine the total abundance, the taxonomic richness and the equitability of the community. By another way, the different microhabitat types were described by specific taxa which were sampled on. This method allowed us to draw up their qualities for macroinvertebrate. An original approach of spatial heterogeneity of the substrate mosaic allowed us to show the secondary influence of the environmental characteristics of microhabitat surrounding on the community in place. The community organization seems to be related to the number of potential sources of colonization by invertebrates of neighbouring habitats, and by the stability of its environment. Finally, results obtained at a station scale demonstrate in particular that the faunistic equitability depends on the patchiness of the substrate mosaic, which probably highlights, at this scale but also at the microhabitat scale, the environmental stability conceptL'objet de ce travail est d'approfondir nos connaissances (1) sur l'organisation des peuplements d'invertébrés dans les différents microhabitats qui constituent le lit d'une rivière, et (2) sur les facteurs environnementaux qui régissent cette organisation. Un échantillonnage séparé des microhabitats a été réalisé au printemps et à l'automne 1993 et 1994 sur 12 stations. La structure des communautés est décrite par un ensemble d'indices biocénotiques dont nous avons précise les propriétés essentielles. Des simulations ont permis de montrer que la nature des microhabitats échantillonnés influence considérablement l'image restituée de la structure du peuplement stationnel, principalement du fait de la répartition en agrégats des invertébrés benthiques. L'étude des facteurs de micro répartition montre que la nature du substrat, la vitesse du courant et, dans une moindre mesure, la hauteur d'eau sont des paramètres majeurs de l'organisation des peuplements de microhabitats. Ces caractéristiques mésologiques traduiraient en fait trois critères écologiques fondamentaux de l'habitat, ses capacités d'accueil, ses potentialités trophiques et sa stabilité, qui déterminent respectivement l'abondance, la richesse taxonomique et l'équitabilité du peuplement. Les différents types de milieux échantillonnés ont par ailleurs été caractérisés par la faune qui y a été rencontrée, ce qui a permis de dégager leurs principales qualités pour les macroinvertébrés. Une approche originale de l'hétérogénéité spatiale de la mosaïque des substrats a permis de montrer l'influence plus discrète de l'environnement autour d'un microhabitat sur le peuplement en place, qui est surtout influence par le nombre de sources potentielles de colonisation par les invertébrés des habitats voisins, et par la stabilité de son environnement. Enfin, les résultats obtenus à l'échelle d'observation de la station montrent en particulier que l'équitabilité faunistique dépend du morcellement de la mosaïque des supports, ce qui traduirait à cette échelle comme a celle du microhabitat, la notion de stabilité du milie

Biomonotony: definition and assessment for macroinvertebrates in European running waters

International audienc

Biological and ecological characteristics of invasive species: a gammarid study

International audienc

Synthèse analytique sur les traits bio/écologiques des amphipodes européens à caractère invasif

International audienc

Bird and amphipod parasites illustrate a gradient from adaptation to exaptation in complex life cycle.

6 pagesInternational audienceTrophically transmitted parasites modify the phenotype of their hosts, sometimes in a way that facilitates transmission. Parasite-induced changes can be either part of a manipulative strategy evolved to improve the transmission success of the parasite, or simply by-products of infection with no health effect. In the former case, manipulation is regarded as a parasite adaptation driven by the probability of being eaten by a suitable next host. Here, we consider the fact that manipulation may also be an 'exaptation': a trait that evolved for a certain use, but which has been co-opted for a new use. According to this view, features built by natural selection for their role (historical genesis) and current utility features at present enhancing fitness of the parasite are different. We describe the behavioural profile of a freshwater crustacean (Gammarus roeseli) when serving as intermediate host to an acanthocephalan parasite (Polymorphus minutus). Although host manipulation by P. minutus is assumed to favour predation by avian definitive hosts (current utility feature), its evolution has been driven by the probability of dying inside non-host predators (historical genesis). This example of an exaptation, taken together with examples of adaptations in closely related host-parasite associations, improves our understanding of the evolutionary genesis of parasites' transmission strategies