Alpine Planaria

The Alpine Planaria (Crenobia alpina), which grows up to 1.5 cm, is considered to be a relict of the Ice Ages. In the saprobic index of water quality, it indicates absolutely clean water. Its distribution area encompasses large parts of Europa and Sibiria. In the Alpine region, it inhabits mountain brooks. North of the Alps, Crenobia alpina has retreated into the ground water after the last Ice Age.

In the high altitude springs of the Rhön mountains, Crenobia alpina is found only in undisturbed, subnatural forest springs. Main threats to this species are the leaching of nitrates into the springs in agricultural areas and the acidification in the coniferous forests.