Action Plan to Combat Ambrosia | Umweltbundesamt

The project refers to no specific climate scenario.

It is known that, due to its late flowering, Ambrosia artemisiifolia will not develop mature seeds in colder climates, so that the species cannot establish itself there. However, reliable information on the precise climatic conditions under which seed maturation does occur is missing. This information is important for pinpointing current habitat boundaries, as well as for predicting the future development of these boundaries in the course of the climate change. We are also missing information on the adaptability of the species to other climates.

The spread of Ambrosia artemisiifolia along roadways and through earth transport during construction work is a further problem that needs to be addressed. Populations recently observed in the Lower Lausitz that have exhibited a change in the phenology of the plant give rise to a concern that Ambrosia may be adaptable enough to be able to establish itself in less congenial climates. This shifts the focus of the plan onto the prevention of the introduction and spread of the plant.

Measures to limit the further spread of ragweed should include the measures to combat its further introduction and dissemination, for example in bird seed and other unground grain feed, or by agricultural machinery and contaminated soil.

Measures to combat existing populations, with the aim of preventing or reducing the further propagation of the plant, are carried out in varying degrees in different regions. It has been shown that the success of these actions depends less on the choice of method than on the consistent implementation of a chosen measure. As ragweed occurs in most German states on roadsides, in private and public greens and in ruderal areas (disturbed lands), mechanical methods such as uprooting and mowing are applied for the most part.