Preliminary monitoring of vegetation in Schwalbeninsel completed

News

The LIFE WILDisland project aims to protect and revitalize the last remaining wild islands along the Danube. The planned measures aim to redynamize the hydrological regimes and remove some physical obstacles, such as groynes and sedimentation to also improve the conservation status of the valuable softwood forests along the banks.

In order to assess and document the effect of the project activities, local monitoring programmes will take place at each of the project sites. In Austria, considerable river restoration measures will be carried out below the Abwinden-Asten Hydropower Plant near Linz as well as in the Donau-Auen National Park, Lower Austria.

An external expert was hired to study the vegetation cover at the two project sites to be able to later compare sample plots before and after the restoration measures.

Following an extensive field work on 78 ha that took place from August to November 2023, we are happy to announce we have some preliminary results from the area below the Schwalbeninsel, Donau-Auen NP.

The survey used sixteen different habitat types to characterize the area. Two large areas could be determined. The northern area, which makes up around 3/4 of the study area, is characterized by a few large polygons. Most of it is covered by hardwood riparian forests. In addition, there is an area close to the Danube where an ageing softwood floodplain with a separated ditch system can be found. The remaining areas are characterized by anthropogenic habitat types (forest edge and scrub vegetation; meadows, fallow land, or other open areas; (overprinted) forestry; paved/ unpaved paths). The separation of the area from the dynamics of the watercourse due to the bank protection does not allow for any development potential. In the southern section, a small-structured island landscape developed before the bank stabilization. Pioneer areas and young succession stages can be found here. In addition, there are permanent and temporary (flowing) waters, silted-up ditch systems, and more or less established softwood riparian forests. The areas in front of the bank stabilization were assigned medium to high development potential.

The expert suggests that the planned revitalization measures will decrease the anthropogenic habitat types and improve the connectivity of the northern alluvial forest areas with the watercourse, through a natural succession of habitats due to the natural development of the banks, as well as through the improved hydrological connectivity of the groundwater with the Danube. The newly created shoreline and the general dynamization of the area are expected to lead to an increase in pioneer and early succession sites. Natural regeneration of the priority FFH habitat type 91E0* softwood meadow is possible on these sites. We can therefore expect significant ecological improvement in the area.

The technical plans for the restoration measures have already been submitted for approvals and we hope to be able to start the practical work by the end of 2024.

Photo credit: Valerie Christ

In the front pioneer vegetation and a shallow, calm water area can be recognized. In the background, an over-aged alluvial forest on the actual Swallow Island is fixed by boulder throw
Alluvial forest with a silting ditch
Abandoned meadow in the dammed area of the floodplain
Small gravel island with pioneer vegetation in front of the block throw
In the front pioneer vegetation and a shallow, calm water area can be recognized. Behind it, the boulder throw and the clearly recognizable groyne separate the old willow forest from the dynamics of the river
Willow bushes on the Schwalbeninsel in a dynamic area
Herbaceous pioneer vegetation on a gravel island. Old riparian forest to the left and right, which is separated from the dynamics of the river by block throw
In the front pioneer vegetation and a shallow, calm water area can be recognized. Behind it, the boulder throw separate the old riparian forest and a meadow from the dynamics of the river.