PRESENT STATE REGARDING THE DISTRIBUTION OF GASTROPODS FROM THE DANUBE, THE DANUBE DELTA AND THE RIVERS OF ROMANIA

The Danube, the Danube Delta and the rivers of Romania represent a geographical space displaying a gastropod fauna specific to the area located between the Carpathians and the Danube. There are 83 species characteristic to each sector of the Danube: upper (51 species), intermediary (51 species), and lower (64 species). Thus, gastropod populations reflect the ecological conditions of their life environment. The Danube Delta, with a great diversity of aquatic ecosystems, displays the same wide range of gastropods (54 species). Due to their physiological and hydrological features, there can be identified gastropod populations specific to each sector of the Romanian rivers (135 species): 14 species in the mountain torrents and streams, 6 species in the sub-mountain and hill sectors of the rivers, 5 species in the plain rivers, 1 species in the glacial lakes and alpine marshes, 3 species in the lakes and pools from the hilly region, 13 species in the lakes and pools from the plain region, 18 species in the salty and brackish lake ecosystems. According to the ecological character of the rivers, the species Lithoglyphus apertus, Radix ampla, Radix balthica, Stagnicola palustris appear more often within the mountain and hilly area; Bythinella austriaca, Amphimelania holandri, Ancylus fluviatilis mostly populate the mountain torrents and rivulets; Theodoxus fluviatilis, Viviparus viviparus, Lithoglyphus naticoides, Esperiana esperi, E. (Microcolpia) acicularis daudebardii are characteristic to the rivers from the plain area. The global evaluation of the gastropods populations from the Danube, the Danube Delta, and the other rivers from Romania represents an important part of the European malacofauna. The synthesis we made may represent a parameter in evaluating the distribution of the gastropods populations within the Danube basin.