Description of solution
Like hardly any other plant species, the tamarisk (Myricaria germanica) characterizes the dynamics of a wild river. This is because the plant can only settle where gravel banks newly emerge during floods. After only a few years, willows and grasses displace the pioneer species. Every river engineering measure such as head storage, bedload barriers, hydroelectric power plants, bank protection or gravel extraction leads to a bedload deficit. The river deepens and narrows, gravel banks can no longer establish themselves. The still existing, higher gravel banks become overgrown with bushes and are no longer subject to the natural dynamics of erosion and restocking. In order to promote the tamarisk under these circumstances, the Bund Naturschutz extracts seeds from the few plants remaining at the Ammer river and rears about 250 plants. At the age of three to four years, they are planted in suitable locations and kept free from competition. A self-sustaining population is to be established from these mother plants. The conditions for this are still good at the Ammer river. The success of this measure is supported by a reduced gravel extraction, the allowing of bank breakages and a redynamization of the Ammer river. Several other wild river species, such as the common sandpiper, the little ringed plover or the gravel-bed grasshopper, all of which are Red List species in endangered wild river habitats, also benefit from this. The measure is part of the project Alpenfluss Landschaften.