Guided tour to the National Park Donau-Auen

The Donau Auen National Park ... a world of its own

"The lower Austrian Danube floodplains are a world of their own. Those who only know the forests, the mountains and the plains of this land do not realize that close to the city a rather solitary and distinctive wilderness exists." Crown Prince Rudolf of Austria, 1888.

The Donau-Auen National Park is protecting one of the last large unbuilt floodplain areas in Europe. Here the dynamics of the flowing stream are still active. The rise and fall of the water levels define life rhythms in the floodplain. The river shaped this landscape with its floods and still nurtures today a large diversity of plants and animals. In the National Park nature can develop free from economic restrictions.

The danube flood plain National Park...

• is a green ribbon between the conurbations of Vienna and Bratislava,
• protects the largest natural riparian wetlands in Central Europe, which are still to a high degree ecologically intact,
• is vitally influenced by the practically free-flowing stretch of the River Danube, which in this area still has the characteristic phenomena of an alpine stream,
• represents a complexity of ecosystems with an enormous diversity of habitats, plant and animal species,
• offers home and refuge to many endangered plants and animals,
• deeply impresses visitors with the particular beauty of its landscape,
• provides a natural overflow for floods,
• guarantees high-quality drinking-water,
• acts as filter and climate regulator for the whole region and
• serves as a recreation area for people living in the surrounding region.

Total area at present: 9,300 hectares owned by the Austrian Federal Forests, the Republic of Austria (Directorate of Inland Waterways), the Municipality of Vienna, and the Municipality of Hainburg. About 60% of this area are forests, approximately 25% are covered by water.

The River Danube forms part of the National Park over a distance of about 36km. Its waters flood the riverine land and thereby determine the natural rhythm of the riparian wetlands. The ecosystem is very dynamic. The highs and lows of water levels (which can vary by as much as 7 metres) show the extreme range of conditions to which the riparian wetlands are subjected.

These varying conditions lead to a diversity of habitats. Major habitats are:

• the River Danube,
• canals and former tributaries of the Danube, all sorts of marshy pools and sloughs,
• gravel banks on islands and riverbanks,
• flat banks with siltation and wetlands,
• steep riverbanks,
• riverine forests (wet and moist wetlands) as well as forests on steep slopes,
• meadows and well drained, dry ground where the vegetation reminds one of savannahs.

Obviously this great range of habitats is the basis for an outstanding diversity of species. There is evidence of

• more than 700 species of vascular plants,
• more than 30 mammal and 100 breeding bird species, 8 reptile and 13 amphibian species and more than 50 different species of fish,
• an abundance of terrestrial and aquatic invertebrates.

Alien species in the National Park ...

Alien plant species play a significant role in the national park. The most recent forest inventory revealed that about 25% of regeneration of woody plants consists of alien species.

Of particular conservational concern is Acer negundo, which forms a dense understorey in willow forests. Fraxinus pennsylvanica spreads in floodplain forests and outcompetes the rare native Fraxinus angustifolia.

Populus x canadensis has formerly been widely planted in the floodplain forest for pulp production. It includes various hybrids of a North American (P. deltoides) and a European (P. nigra) poplar species, cultivated for their fast growth. Molecular studies show that up to 10% of poplar regeneration in the national park consists of back crosses between P. x canadensis and P. nigra.

Robinia pseudacacia and more rarely Ailanthus altissima have invaded dry meadows and dry forests in rarely flooded areas of the national park, with detrimental effects on these habitats of high conservation value.

Most of the more important alien animal species are difficult to see, because living in the water (e.g. Neogobius spp., Lepomis gibbosus, Trachemys scripta elegans) or in other organisms (e.g. the large american liver fluke Fascioloides magna) or simply hidden in more or less remote places.

Thus, the national park management has implemented eradication measures to minimize the negative impacts of invasive alien species.

Tour programme

The guided tour will bring us into the heart of the National Park, where we will find a great variety of habitats, encompassing the Danube river, pioneer vegetation on gravel banks, oxbow lakes, water vegetation, tall herb vegetation, floodplain forests and semi-dry meadows. We will present alien species and will visit reference sites, where problems and success of eradication measures will be shown and discussed.

Further, we will visit the project areas of two large-scale LIFE-projects, which aim to induce increase natural sedimentation and erosion processes by connecting former canals to the main river channel.

The guided tour is organised in collaboration with the national park management. Lunch will be included in the guided tour.