La malacofaune du site Natura 2000 du lac de Saint Léger et mention de Vertigo angustior Jeffreys, 1830 (Mollusca, Gastropoda, Vertiginidae) pour les Alpes-de-Haute-Provence

In 2007, the non-marine mollusc of the Natura 2000 site FR9301546 Lac de Saint Léger and its catchment were surveyed on the basis of 19 and 13 stations respectively. This survey allowed us to find 11 species of freshwater molluscs in the lake (9 snails and 3 species of pea mussels) and 21 terrestrial species in the fen (5 slugs and 16 land snails), among which Vertigo angustior Jeffreys, 1830. It is the first report of this species in the Alpes-de-Haute-Provence. In the catchment, 25 land species (5 slugs and 20 land snails) were discovered but no freshwater species. The freshwater fauna of the lake is very poor due to the oligotrophic conditions of its water. In contrast, the land fauna of the fen, located at 1 300 m a.s.l., is very similar to those of wetland plains. The malacofauna of the catchment (about 50 ha) is relatively poor considering its geographic position in the French Alps.