In the region of Dietikon-Spreitenbach-Heitersberg (Limmat Valley), invasive neophytes were analyzed and measures for dealing were proposed. For this purpose populations of invasive neophytes and phe- nomenologically defined habitats were mapped at a scale 1:10 000 in 2007. The map shows a strong concentration of invasive neophytes in the areas of settlement. 12 species that occur in the study area are from the Black List, 3 from the Watch List. The following plant species are the most widely spread in the study area and appear dominant in one third of the habitats: Butterfly Bush, Giant Goldenrod and Himalayan Blackberry. Typical spreading sources of inva- sive plant species are residential areas. The spreading itself occurs mainly along rivers or traffic ways. The comparison between the Limmat Valley and the Upper Rhine/Domleschg Valley shows that there occur nearly the same species. But their occurrence is smaller in the Grisons Alps. The sources of expansions and the ways of proliferation are the same.
Areas with prior need for action are proposed because of evaluations, additional collecting of vegetation data that show the impact of Japanese Knotweed on biodiversity and a priority list.