Molluscs (Mollusca) are a species-rich phylum of invertebrates. With about 130,000 species worldwide, molluscs are the second largest group of animals after insects. About 600 species are known throughout Germany. Molluscs are characterised by a sparsely jointed, gland-rich and generally soft body.

Zwei Weinbergschnecken bei der Paarung. © U. Müller
The protected Roman snail (Helix pomatia) is the largest native land snail.

During extensive zoological surveys in 1995, 130 mollusc species were found in the Schaalsee region. Freshwater molluscs of large and small water bodies as well as species of forest and swamp areas are predominant. Drought-loving species are rare. On acidic or boggy soils, the mollusc communities are, as usual, poor in species and individuals, with nudibranchs predominating. In some of these areas, Columella aspera occurs.

The consistency with which small forest waters are colonised by typical mollusc communities is remarkable. These also include endangered species such as the moss bladder snail (Aplexa hypnorum), the Anisus spirorbis or the elongated mud snail (Omphiscola glabra). The frequent occurrence of the Roman snail (Helix pomatia) is very striking for visitors.