Klagenfurt Spring Snail (Graziana klagenfurtensis)

Spring Snails (Hydrobiidae).

Klagenfurt spring snail (Graziana klagenfurtensis). Picture: © Alexander Mrkvicka, Vienna.
Picture: © Alexander Mrkvicka, Vienna.
The orange coloured operculum, as well visible in this speci- men, tells Graziana and Belgrandiella apart from similar spe- cies of Bythinella (Bythinellidae).

Systematik der Truncatelloidea Caenogastropoda > Littorinimorpha > Truncatelloidea

Superfamily Truncatelloidea Family Hydrobiidae Unterfamilie Belgrandiellinae Belgrandiella Graziana Unterfamilie Horatiinae Sadleriana Unterfamilie Hydrobiinae Peringia (Mudflat snails) Unterfamilie Pyrgulinae Pyrgula Family Bythinellidae Bythinella Family Moitessieridae Bythiospeum Family Amnicolidae Marstoniopsis Family Lithoglyphidae Lithoglyphus Family Tateidae Potamopyrgus Family Emmericiidae Emmericia Family Bithyniidae Bithynia Source: WoRMS: MolluscaBase eds. (2025): Truncatelloidea J.E. GRAY, 1840.

Spring snails are minute freshwater gastropods that often occur in only a single spring or a small group of nearby springs – some even inhabit groundwater systems. As a result, they are extremely sensitive to water pollution and falling groundwater levels. Taxonomically, they belong to several families of freshwater snails, most notably the mud snails (Hydrobiidae) and true spring snails (Bythinellidae).

One example is the Klagenfurt spring snail (Graziana klagenfurtensis, family Hydrobiidae). This tiny species grows to just about 1.5 mm in size and was first described in 1994 from a single spring near Klagenfurt (Carinthia, Austria). At the time, it was thought to occur in six closely spaced springs in the Sattnitz region south of Klagenfurt, although more recent assessments suggest a more cautious estimate of just five springs.

All five (or six) of these springs have been negatively affected by environmental pollution and groundwater extraction.

The Klagenfurt spring snail (an unofficial common name) is an endemic species, known only from these few springs in a small area south of Klagenfurt. However, these springs were captured decades ago for water use, and the snails now survive only in the overflow channels. If these overflows were to dry up – either during drought years or due to increased water withdrawal – the population in that spring would be lost. In one case, a gravel road runs directly past a spring, allowing fine sediment to be washed into the water during heavy rain.

To date, no specific protection measures or spring management plans have been put in place for this critically endangered snail species or for the springs it inhabits.

Graziana klagenfurtensis is listed on the Red List of Threatened Species. Due to the precarious state of its habitat and its highly restricted distribution, the species is considered Critically Endangered (cf. IUCN threat categories).

IUCN Threat Categories

Systematik:

Ordnung: Littorinimorpha
Überfamilie: Truncatelloidea
Familie: Hydrobiidae
Unterfamilie: Belgrandiellinae
Graziana klagenfurtensis

Fauna Europaea.
WoRMS: MolluscaBase eds. (2025): Graziana klagenfurtensis HAASE, 1994.

Quelle:

REISCHÜTZ, P. 2009. Graziana klagenfurtensis. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.1.

Literatur:

HAASE, M., MILDNER, P. (1996): Hydrobiidae (Gastropoda, Prosobranchia) Kärntens: Zur Verbreitung der Gattung Graziana. Carinthia II 186 (106): S. 571 - 574. ( PDF).