Bilan des connaissances sur les espèces de mollusques continentaux d’intérêt communautaire de la Directive

To date, four priority species listed in of the European Union Habitats and Species Directive are present in the region of Picardie. The species concerned are: Vertigo moulinsiana (Dupuy, 1849), Vertigo angustior Jeffreys, 1830, Margaritifera auricularia auricularia (Spengler, 1793) and Unio crassus Philipsson, 1788.Except specific studies carried out on the land snail Vertigo moulinsiana in the site of Cessières-Montbavin and the National Natural Reserve of Saint-Quentin, any studies or any conservation schemes are made on the three other species in the region Picardie. This paper gives an update on the distribution, some data on the habitat requirements and threats of these four species concerned by the Habitats and Species Directive in Picardie.Although the knowledge on the habitat requirement and the distribution of these species are insufficient, there is possible to draw some conclusions about their status. Among these four species, the most localised and the most threatened are the freshwater molluscs Margaritifera auricularia auricularia and Unio crassus. Vertigo angustior and Vertigo moulinsiana are respectively in the third, the fourth positions in the scale of threat.