The situation is different with another species that researchers investigated more closely. The Oregon grape (Mahonia aquifolium) originates from the West of the USA. In Oregon, the evergreen bush with its salient yellow blooms is even the official plant of the US Federal State and is therefore also known as "Oregon grape". In Europe the Oregon grape has a similar relative: the European Barberry (Berberis vulgaris). Native insects had millions of years time to adapt to the European Barberry and could now comparatively easily "switch" to the Oregon grape. The Oregon grape on the other hand could not develop any defence mechanisms against its herbivores.
Nevertheless, it prospers so well in Central Europe that the Swiss Commission for the preservation of wild plants requests owners of gardens to do without the cultivation of Oregon grape as a preventative measure: "Should one already have this species in one's garden, one must absolutely prevent any further propagation, on the one hand by removing the infructescence, and on the other hand by constantly removing any young shoots." In spite of herbivores, the Oregon grape is able to flourish, cover forest floors comp
|Contact: Tilo Arnhold|
Helmholtz Association of German Research Centres