Below Peißenberg, the connections of the old arms and flood channels with the river Ammer were interrupted. The resulting siltation tendencies at the dry falling old waters as well as the missing flooding of the alluvial forest lead to a creeping deterioration of the natural habitats. Only a few remnants of alluvial forest are preserved at the Ammer. Due to the prevented flooding, the tree species composition changes from the original grey alder forest to ash silver willow communities. By diverting several spring streams and connecting them to a system of former flood channels and still existing old waters of the Ammer, the WWF Germany wants to reactivate and "redynamize" small streams. As a result, the adjacent alluvial forest will also be flooded at higher water levels and can thus develop naturally again.