First Report on the Non-Indigenous Triclad Girardia tigrina (Girard, 1850) (Tricladida, Dugesiidae) in Serbia, with Notes on its Ecology and Distribution

Girardia tigrina (Girard, 1850) (Turbellaria, Tricladida, Dugesiidae), a native freshwater triclad of North America, is a widespread species, which has been introduced by human activities into various parts of the world, including Europe. The aim of this paper is to contribute to the knowledge of this species by presenting its first record and recent distribution in Serbia. Girardia tigrina was recorded in Serbia in 2008 in the lower stretch of the Kolubara River. After this initial finding, the species was identified only a few more times, but with low abundance. Its presence only in the northern part of Serbia, in the Danube River and in its proximity, points to the Danube River and its larger tributaries (the South invasive corridor) as the main route of its spread in the country. Our data suggest that G. tigrina should not be considered an invasive species but as an alien species with a minor impact on native communities.