Species account for Anisus vorticulus (Troschel, 1834) (Gastropoda: Planorbidae), a species listed in Annexes II and IV of the Habitats Directive

Information from more than hundred published sources, augmented by previously unpublished expert knowledge, is compiled to build up a species account for the Western Palaearctic planorbid gastropod Anisus vorticulus (Troschel, 1834), threatened at European level and recently listed in the EU Habitats Directive. The account summarizes the available data about the species, including identification, environmental requirements, life cycle, dispersal, food, geographic distribution and threats, together with recommendations for site management and survey procedures. The species occurs in both natural habitats (lake littoral, streams, river floodplains) and man-made habitats (drainage ditches, excavations). It is mostly associated with calcareous, moderately well vegetated habitats, especially with abundant floating plant coverage. The species has normally an annual life-cycle but the few available data suggest a high spatial and inter-annual variability in its phenology. To date, conservation measures for the species included vegetation removal and translocation. A dearth of quantitative and general information is obvious for almost all aspects of the biology and ecology of the species and prevents informed conservation recommendations being made.