The Danube river and its floodplains have little of their original ecological characteristics still intact due to river regulation, low-water regulation and the construction of an almost uninterrupted chain of power plants along the main river. Floodplain habitats have also been strongly affected by damming and river regulation. The project area, the Tullnerfelder Donau-Auen, contains 42 species protected under the EUs Birds Directive and Annex II of the Habitats Directive. The majority of species are aquatic or prefer wetland habitats, and the bulk of habitat types listed are either aquatic or depend on hydrological dynamics. In the Danube and its floodplains, a key missing habitat type is permanently connected side arms, which provide spawning grounds and nurseries for rheophilic fish species (i.e. preferring swiftly-flowing water) and shelter from ship-induced waves.
LIFE Network Danube+ will create around 35 ha of these urgently needed habitats, permanently connected side arms. A large natural sidearm and several newly created fishways will allow fish to migrate without barriers to one of the last free-flowing sections in the Upper Danube, as well as to several tributaries and floodplain waters. Restoration measures within the floodplains and tributaries will create key habitats such as spawning grounds and nurseries, so enhancing fish production. The project is predominantly targeted at the protected rheophilic fish species of the Danube and its floodplains, but also at the other (semi) aquatic species.
Its specific objectives are: improving habitat conditions by creating new habitats that are no longer abundant in the Danube and its floodplains but necessary for the survival of the majority of the endangered species. These include: - flowing water habitats such as shallow banks, riffles and steep erosional banks necessary for the rheophilic fauna and the kingfisher (Alcedo atthis); and - shallow floodplain habitats necessary for the typical wetland fauna; improving habitat conditions by interlinking existing or newly created habitats, thus making them accessible, by: - reconnecting Danube river sections to allow rheophilic fish access to free-flowing stretches; - reconnecting tributaries with suitable spawning grounds; and - interlinking highly productive floodplain habitats. demonstrating the suitability of a targeted stepwise approach for achieving the goals of the Habitats and Birds directives and the EU Water Framework Directive on a large spatial scale; and demonstrating the positive impact of a constructed wetland on the water quality and lifetime of a large floodplain water body.
Expected results: interlinking of Danube river sections: by the end of the project, unhindered fish migration will be possible between the Iron Gates gorge in Serbia and the Ybbs-Persenbeug hydropower plant in Austria (over 1 100 km) including the two last free-flowing stretches of the Austrian Danube; unhindered fish passage in a large part (more than 10 km) of the floodplain through the construction of five fishways; unhindered fish passage to several tributaries, including Krems, Kamp, Mhlkamp, Schmida and Gllersbach, making a total of over 150 km of riverine habitat accessible; interlinking of three Natura 2000 sites through blue corridors; creation of new fluvial habitats through the construction of a 13-km bypass; creation of gravel and sand banks in the floodplains (around 150 000m); creation of 5 ha of semi-aquatic habitats in the floodplains; preservation of 28 (semi) aquatic species and five wetland-dependent species, as well as seven aquatic habitat types and three dependent on fluvial dynamics; significant expansion in the habitat range of one of the most threatened bivalve species, the thick shelled river mussel (Unio crassus), and the bitterling (Rhodeus amarus) - potential of 13 km in the newly created side channel and 5 ha in the floodplain; increase in habitats for the kingfisher, which will benefit from steep erosional banks within the 13 km-long side channel, leading to higher numbers of breeding pairs; and improvement in the water quality and potential lifetime of a large floodplain water body due to reduced sediment and nutrient input.