Open Access

Dietmar Brandes, Meike Müller

• Artemisia annua ist ein gutes Beispiel für eine invasive Art in Mitteleuropa, die sich nach einer längeren Lag-Phase plötzlich ausbreitet. Die Art stammt aus der temperaten Zone Asiens, wo sie ihre natürlichen Vorkommen an sandigen Fluß- und Seeufern sowie Wadis der Halbwüsten und Steppen besitzt. Synanthrope Vorkommen finden sich heute in Zentralrussland, Zentral- und Südeuropa sowie in Nordamerika. Wie auch bei anderen invasiven Arten ist auch hier die erfolgreiche Ausbreitung eng mit instabilen Habitaten verbunden. So nischt sich Artemisia annua in Ruderalgeseilschaften ± trockener Böden ein; ebenso werden sandige und kiesige Flußufer besiedelt. Eine Übersichtstabelle der bislang aus Mitteleuropa bekannten Aufnahmen wird präsentiert.
• Artemisia annua is a good example of an invasive species in Central Europe, which after a long lag phase has suddenly begun to spread. The species is native to the temperate zone of Asia, where its natural habitats are sandy river banks and lakeshores as well as wadis in the steppe and semidesert. Invaded areas are central Russia, central and southern Europe and North America. The successful spread of Artemisia annua is closely linked to unstable habitats. It finds a niche in ruderal plant communities of dry soils as well as sandy or gravelly river banks. We studied both the population biology and ecology of the species. The most important reasons for the success in its spread are extremely high diaspore production, low requirements for the germinating temperature as well as high germination capacity. The requirements for nutrient richness are low. Nitrogen fertilizing, however, leads to increased diaspore production. Artemisia annua reacts to increasing interspecific competition with plasticity instead of mortality. A survey of the phytosociological behaviour of Artemisia annua in Central Europe is also presented. What effects on other species may be linked to the spread of Artemisia annua? Until now, there has been no evidence that other species may be endangered by its spread. However, the species may cause severe allergies in humans.