The Swedish Fauna of Freshwater Snails—An Overview of Zoogeography and Habitat Selection with Special Attention to Red-Listed Species

The aim of this paper is to describe and analyse the present Swedish fauna of freshwater snails, based on material in museum collections, the literature, records in conservation reports and in databases. The Swedish fauna comprises 50 species (42 indigenous and 8 introduced). Moreover, 31 out of 50 species belong to the superorder Hygrophila. The species’ zoogeography, ecology and conservation status are highlighted. The species distributions can roughly be classified according to four different geographical groups of patterns. 23 species have their northern limit within or close to the limes norrlandicus, an important biogeographical transition zone in Central Sweden. The history of the exploration of the fauna and groups/species with taxonomical/determination problems are discussed. The six species, which are present in the Swedish National Red List, are discussed in detail. Main threats include the exploitation of Swedish rivers and the changing of insolation in small water bodies due to vegetation alteration, eutrophication and drainage. The threat status of the species in the national Swedish list and the general European list are compared and show a high degree of agreement.