Re-naturalisation of lakeshore and creation of protected zones - LIFE+ Alte Donau

Some 1,500 metres of the Alte Donau lakeshore have undergone substantial structural improvement as a result of the LIFE+ project.

Densely vegetated shoreline of the Alte Donau

The Alte Donau needs bulrushes, bur-reed and iris as well as reed beds, varied shoreline structures and trees and shrubs typical of riparian woodland.

In heavily used bodies of water, near-natural refuge zones are especially important in maintaining ecological function. The shoreline zones, in particular, provide shelter for animals and plants. The long-term goal of the City of Vienna is to increase the proportion of near-natural stretches of lakeshore to at least one third of the perimeter of the Alte Donau.

Status quo before the LIFE+ project

The shores of the Alte Donau were last assessed according to ecological criteria in 2015. The assessment showed that some 25 percent of the lakeshore was near-natural in character (for example with reed beds), while 15 per cent was well structured. The major proportion of 60 percent, however, consisted of walled banks and had no typical lakeshore vegetation.

Measures implemented under LIFE+

Within the framework of the LIFE+ project, two stretches of lakeshore on the upper section of the Alte Donau were chosen as pilot zones for re-naturalisation. In addition, a large number of individual measures were also implemented to safeguard the ecological function of the Alte Donau and improve biodiversity on land and in the water. Reed beds in danger of drying out were rejuvenated, for example, and deadwood was introduced at various points around the lake to provide shelter for fish. Planting of wildflower strips in several less frequented areas close to the lakeshore has improved biodiversity on land.

In addition, the number of near-natural stretches of lakeshore has also been substantially increased by means of natural succession, i.e. as a result of deliberate less intensive management of the shoreline vegetation. Encouragingly, a review of overall progress shows that the share of near-natural reed beds has risen by approximately 30 percent as a result of measures implemented under the LIFE+ project.

Pilot projects

New lakeshore vegetation

On the 450 metre stretch of lakeshore between Drygalskiweg and Mühlschüttelgasse, stones and pebbles were piled up on the lakebed and then planted with various types of reeds. The second stretch of lakeshore to be re-naturalised in this way is in the northern section of the Alte Donau at Broßmannplatz. Here, bundles of branches were fixed to the lakebed and planted with reeds, and a waterlily zone was planted in the water.

Reeds and trees at the ArbeiterInnenstrand

The new ArbeiterInnenstrand sunbathing lawn borders another near-natural stretch of lakeshore. The existing stands of reeds were extended when the premises were regenerated and opened to the public as a sunbathing lawn. Over 60 new trees of native species such as poplars, willows and limes have been planted.

Habitat for young fish and amphibians

Sheltered new ponds for amphibians and shallow pools for juvenile fish with access to the open water have been dug on several stretches of shoreline with existing reed beds. These new pools and ponds can be found on the western shore of the Kaiserwasser arm, alongside Wagramer Straße and around the southernmost tip of the Alte Donau.

Refuge zones in the water

In little-used zones of water close to the lakeshore, a number of permanent refuge zones were created in which the submerged aquatic vegetation is left unmown. These zones serve as undisturbed spawning grounds and areas of shelter, chiefly for fish.

Planting of young trees around the Alte Donau

Mighty old black poplars and willows characterise the typical landscape around the Alte Donau. Close to 1,200 trees line the grassy areas around the lakeshore. Many of these huge and impressive old trees have now reached their natural age limit. In order to ensure the long-term preservation of the typical tree species around the Alte Donau, a total of 245 new saplings of habitat-appropriate species were planted or left in place under the auspices of the LIFE+ project, and invasive, non-native species (neophytes) such as ailanthus and robinia were removed.

Living with beavers

Conservation of the heavily protected European beaver also played a role in the LIFE project. After a number of years, some of the recently planted willow saplings will thus be given over to the three resident beaver families on the Alte Donau for use as a winter food supply.

Logo of the LIFE+ Programme of the European Union: The word "Life" in yellow, surrounded by yellow stars

The LIFE+ Alte Donau project was funded under the LIFE+ Programme of the European Union as part of the "Environment Policy and Governance" strand.

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City of Vienna | Water Management
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