Danube-Auen National Park on both land and water, and other invertebrates, the total number of species in Donau-Auen National Park is estimated to be at least 5,000. Danube-Auen National Park Donau-Auen National Park () covers 93 square kilometres in Vienna and Lower Austria and is one of the largest remaining floodplains of the Danube in Middle Europe. The German word Aue (variant Au) means "river island, wetland, floodplain, riparian woodland", i.e. a cultivated landscape in a riparian zone. The words Aue and Au occur in a large number of German place names—including Donau, the German word for the Danube River—and refer to forests,
Source of the Danube springs which differed in size or the starting point of a certain headwater also had a mythological meaning. This was reflected in holy springs/ water sanctuaries or in the worship of Naiads. This was also the case with the source of the mightiest river in the Roman Empire. The Danube river emanating from the Abnoba mountains was considered to be a river or spring goddess. In contrast to the more mythological role, the hydrological significance of the source of the Danube is uncommonly small. This is because the Danube gives an important part of its water to the Rhine both