Krebsschere (Stratiotes aloides) in Naturschutzweihern der Schweiz

Abstract

Water Soldier (Stratiotes aloides) is an aquatic macrophyte which colonizes shallow water zones of meso- to eutrophic lakes, lowland rivers and ditches. It is distributed in northern and eastern parts of Central Europe as well as in southern Scandinavia. In the past it has been introduced in other regions of Europe like France and Switzerland. Since several years Stratiotes aloides has been planted. out in newly created ponds where it had rapidly overgrown most of the water surface. By introducing this neophyte conservationists intend to foster the pond fauna. However, the consequences for the pond ecosystem are disadvantageous. Allelopathic effects inhibit the growth of other hydrophytes and planktic algae. In consequence, faunistic diversity decreases and over-growing increases. The man- agement of ponds should aim at creating habitats similar to the stagnant waters which existed more than 150 years ago, when the floodplains were still natural landscapes.