Bidens pilosa und ihre Einbürgerungschancen in den Ländern der Europäischen Union

Abstract

Bidens pilosa, assumed to originate from tropical parts of America, is nowadays in more than 40 countries all over the worid one the worst weeds. On the other hand the species is of interest not only for its natural substances but also as a potential drug against malaria. In parts of Africa the leaves are eaten like spinach. Spreading is at the moment first of all recognized on the Canary Islands. Because of this in-vading and establishing have been investigated taking as examples La Palma, the most humide island situated farest in the west, and Fuerteventura, the most „African' island situated farest in the east. The ecological amplitude of Bidens pilosa is very large also on both islands, therefore the species is not suitable as a character species. Because Bidens pilosa is spreading to Europe, this paper discusses the investigations carried out on germinating and chances for establishing of Bidens pilosa taking in account the published knowledge of its biology and ecology. Our own experiments demonstrate that Bidens pilosa is also able in Central Europe to complete its life cycle during one Vegetation period, that the achanes have high germinating capacity over years, even under water. It is shown that also in Germany, small populations may survive at favourable habitats for several years. The chances for establishing of this alien are therefore estimated as relatively good.