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,
Commissions of the Danube River it lasted eighty-two years. A separate commission, the International Danube Commission, or IDC, was authorized to control commerce and improvements upriver beyond the Danube Delta and was supposed to be permanent, but it was not formally organized until after 1918. The European Commission of the Danube was the first — and for a long time the only — international body to have serious police and juridical powers over private vessels and individual people, and it was seen in 1930, for example, by history professor Glen A. Blackburn of the United States as a "unique" organization. Without territorial possessions, it is