Approche écologique de la malacofaune d'un milieu anthropisé : le « parc des Beaumonts » à Montreuil (Seine-Saint-Denis, France)

International audienceIn the Natura 2000 site of Beaumonts Park (Mon-treuil, Seine-Saint-Denis), located 6 km east of Paris, hand-collecting and litter sampling has been undertaken in order to study land and freshwater molluscs. This park provides a good example of a highly modified environment in which the effects of disturbance on the land snail fauna can be studied. The main aim of this study is to provide more complete inventories and to document the species of snails and slugs from Seine-Saint-Denis. Altogether 43 molluscan taxa were recovered in the park, of which 9 were freshwater species. The assemblages were classified into the ecological groups commonly used in palaeoecological research to characterize the nature of the different environments. Five ecological groups are recognizable in each litter sample but they occur in different proportions, depending on the extent of human disturbance. Although some woodland or xerophilous species are restricted to their preferential environment, human disturbance gives rise to the homogenization of the fauna where highly adaptable species have an advantage over others. Human impact is also illustrated by the presence of introduced species such as Helix lu-corum. These elements provide a perspective on the relatively high biodiversity suggested by the species list.Des recherches à vue et des prélèvements volumiques ont été effectués sur le site Natura 2000 du parc des Beaumonts (Montreuil, Seine-Saint-Denis) afin d'étudier sa faune de mollusques continentaux. Situé dans une commune à 6 km du centre de Paris, ce parc permet d'étudier la mala-cofaune d'un espace anthropisé. L'objectif principal de l'étude est de compléter les inventaires partiels précédemment effec-tuées et documenter les espèces du département de la Seine-Saint-Denis. Au total 43 taxons dont 9 d'eau douce sont recon-nus dans le parc. Le second objectif est de mettre en oeuvre une approche écologique. L'analyse des données des prélèvements volumiques à partir des groupes écologiques a permis d'appréhender la malacofaune sous un aspect qualitatif et quantitatif. Les cinq groupes écologiques sont présents dans chacun des prélèvements mais dans des proportions diffé-rentes. Les résultats montrent l'impact de l'anthropisation sur les populations malacologiques. Bien que certaines espèces forestières ou xérothermiques se cantonnent à leur milieu préfé-rentiel, l'anthropisation donne lieu à un effet de d'homogénéisation des faunes où les espèces à forte capacité d'adaptation sont favorisées. L'impact de l'homme est égale-ment illustré par la présence d'espèces introduites telles qu' Helix lucorum. Ces éléments relativisent la forte biodiversi-té apparente suggérée par la liste d'espèces. Mots clés : biodiversité en ville, escargots, synanthropiques, malacofaune, Montreuil, groupe écologique

Approche écologique de la malacofaune d'un milieu anthropisé : le « parc des Beaumonts » à Montreuil (Seine-Saint-Denis, France)

International audienceIn the Natura 2000 site of Beaumonts Park (Mon-treuil, Seine-Saint-Denis), located 6 km east of Paris, hand-collecting and litter sampling has been undertaken in order to study land and freshwater molluscs. This park provides a good example of a highly modified environment in which the effects of disturbance on the land snail fauna can be studied. The main aim of this study is to provide more complete inventories and to document the species of snails and slugs from Seine-Saint-Denis. Altogether 43 molluscan taxa were recovered in the park, of which 9 were freshwater species. The assemblages were classified into the ecological groups commonly used in palaeoecological research to characterize the nature of the different environments. Five ecological groups are recognizable in each litter sample but they occur in different proportions, depending on the extent of human disturbance. Although some woodland or xerophilous species are restricted to their preferential environment, human disturbance gives rise to the homogenization of the fauna where highly adaptable species have an advantage over others. Human impact is also illustrated by the presence of introduced species such as Helix lu-corum. These elements provide a perspective on the relatively high biodiversity suggested by the species list.Des recherches à vue et des prélèvements volumiques ont été effectués sur le site Natura 2000 du parc des Beaumonts (Montreuil, Seine-Saint-Denis) afin d'étudier sa faune de mollusques continentaux. Situé dans une commune à 6 km du centre de Paris, ce parc permet d'étudier la mala-cofaune d'un espace anthropisé. L'objectif principal de l'étude est de compléter les inventaires partiels précédemment effec-tuées et documenter les espèces du département de la Seine-Saint-Denis. Au total 43 taxons dont 9 d'eau douce sont recon-nus dans le parc. Le second objectif est de mettre en oeuvre une approche écologique. L'analyse des données des prélèvements volumiques à partir des groupes écologiques a permis d'appréhender la malacofaune sous un aspect qualitatif et quantitatif. Les cinq groupes écologiques sont présents dans chacun des prélèvements mais dans des proportions diffé-rentes. Les résultats montrent l'impact de l'anthropisation sur les populations malacologiques. Bien que certaines espèces forestières ou xérothermiques se cantonnent à leur milieu préfé-rentiel, l'anthropisation donne lieu à un effet de d'homogénéisation des faunes où les espèces à forte capacité d'adaptation sont favorisées. L'impact de l'homme est égale-ment illustré par la présence d'espèces introduites telles qu' Helix lucorum. Ces éléments relativisent la forte biodiversi-té apparente suggérée par la liste d'espèces. Mots clés : biodiversité en ville, escargots, synanthropiques, malacofaune, Montreuil, groupe écologique

La datation radiocarbone sur coquilles de mollusques continentaux : quelles limites et quels usages ?

International audienc

La datation radiocarbone sur coquilles de mollusques continentaux : quelles limites et quels usages ?

International audienc

Contributions of the study of continental Mediterranean Holocene fossil mollusc assemblages to the conservation of an endangered group

International audienceIn Quaternary studies, fossil land shells are usually studied to investigate past environments and climates across various spatial and temporal scales. Over the last ten years, new molluscan successions from northeastern Morocco and southern Spain have revealed a high diversity of land snail assemblages during the Holocene. Nowadays, the highly anthropized Mediterranean Basin is considered one of the most sensitive areas to landscape and biodiversity modification due to climate changes driven by human activities. As one of the most threatened invertebrate groups, many Mediterranean land snail species require major conservation measures to ensure their survival.On the basis of new Moroccan and Spanish sequences (Aït Said ou Idder; Blirh; Oued Charef, Galera) and a review of the existing paleomalacology literature, we discuss the significance of Holocene molluscan records from a perspective of paleobiology conservation. Most of the sequences provide records from the Middle Holocene (8200 – 4200 Before Present) consisting of a rich hygrophile fauna as common components. V. moulinsiana and V. angustior, both protected species under the European Directive, occur regularly. V. enniensis is common in several Holocene sites, but has a current distribution limited in Spain and is unknown living in Morocco. Likewise, the occurrence of the endemic O. aragonica at Galera and Baides shows that this species had much larger populations and a wider distribution during the Holocene which support its endangered species status Middle Holocene molluscan successions provide an historical perspective of the occurrence of hygrophilous species before aridification and increased human impact led to the disturbance and fragmentation of wetland habitats. Molluscan fossil records are an ideal temporal tool to better understand the parameters that have shaped today's biodiversity and to identify the most vulnerable taxa

Can an artificial cave be a hotspot for mollusc diversity? Overview of land snail biodiversity underneath Paris and surrounding area

International audienc

Can an artificial cave be a hotspot for mollusc diversity? Overview of land snail biodiversity underneath Paris and surrounding area

International audienc

Du tuf et des coquilles : reconstitution croisée des paléoclimats et des paléoenvironnements holocènes

International audienc

Du tuf et des coquilles : reconstitution croisée des paléoclimats et des paléoenvironnements holocènes

International audienc

A relict or new immigrant? The first record of the planorbid Gyraulus riparius (Westerlund, 1865) in France

International audienceA population of a ramshorn snail species new to the French malacofauna, Gyraulus riparius (Westerlund, 1865), has been discovered in the fen surrounding Lake Cerin in southern Jura, eastern France. This population is located more than 450 km south of the previously known localities in Germany, and the species’ status as indigenous to France is therefore discussed. A review of palaeontological data show that the species has been recorded in eastern France during cold periods of the Middle and Lower Pleistocene. Furthermore, Lake Cerin is a small lake of glacial origin, located at an altitude of 766 m a.s.l., with little impact from human activities and inhabited by numerous threatened and protected boreo-alpine species. We postulate that this population indicates a wider past distribution, especially in the south, although we cannot exclude the hypothesis of a more recent introduction (natural or anthropic). We propose that G. riparius should be treated as a species native to France, as defined by the International Union for the Conservation of Nature, and targeted by a conservation and knowledge programme