For the Tyrolean Lech Nature Park, the survival of the natterjack toad(Epidalea calamita) has become a matter of the heart. For several years, a species protection program for the natterjack toad has been implemented to secure the population of Austria's rarest amphibian. The main aim of the measures is to preserve or restore suitable natural habitat. Natterjack toads need open, sandy areas in floodplain forests and suitable water bodies where they can spawn.
To stabilize the natterjack toad population, new spawning pools have been constructed based on a scientific survey of population size, migration routes, and terrestrial habitats.
In the floodplain forest area of the Tyrolean Lech near Oberpinswang lies one of the last three nationwide occurrences of the Natterjack Toad. As an acutely endangered, strictly protected species, it is the special focus of the project "River morphological redynamization of the forelands to promote selected flagship species".
At Oberpinswang, local bank obstructions have caused the Lech to deepen by about three to four meters. With annually recurring water levels, it therefore no longer reaches the floodplain forest in this area. The floodplain forest area is no longer flooded and is becoming increasingly overgrown. Where there were sparse floodplain forests with sandy bottom areas a few years ago, there are now dense forests that make survival impossible for the natterjack toad, among others.
Two major construction measures were carried out torevitalize the Lechau near Oberpinswang from October 2013 to April 2015. Firstly, a 60 m wide and 12 - 25 m long invert ramp was constructed in the riverbed. At the same time, the orographic right bank of the river was deliberately lowered in some places to restore the natural dynamics. In the floodplain forest itself, clearing work was carried out on an area of approximately 2.3 ha and the soil structures were opened up, so that a 660 m long flood channel was created, which will be flooded during recurring higher water levels.
But it is not only for the natterjack toad that the implementation of this project creates a basis for life. Other key species for dynamic river systems, such as the German tamarisk and the dwarf bulrush, now also have a chance to survive here again and increase their populations. The redynamization in Oberpinswanger Au creates retention areas and therefore contributes significantly to flood protection.