Invasive plant species can flourish better in their new homes than in their place of origin. The reasons for this can be genetic changes or the lack of herbivores such as insects that first have to adapt to the newcomers. These are the conclusions of researchers from the Helmholtz Centre for Environmental Research (UFZ) from their research on Buddleia or the Butterfly bush (Buddleja davidii) and Oregon grape (Mahonia aquifolium). Due to this, invasive plant species would have an advantage over other native plant species and could therefore pose a threat to the ecological balance, as researchers have written in the scientific journal Diversity and Distributions.
It blossoms in blue, white or lilac in many gardens.
Buddleia was introduced to Europe about one hundred years ago from China and has been cultivated since then. The ornamental shrub soon became popular, but not only in gardens. In post-war Germany the shrub was also able to spread on the rubble of bombed inner cities and in the meantime Buddleia grows wild in large parts of West and South West Germany. Only in the continental East of the country, propagation is hindered by winter frosts. Although the blossoms of the Buddleia are aesthetically pleasing and provide a food source for butterflies, this beauty has a dark side to it however. This immigrant also known as the butterfly bush can easily go to seed and form dense populations. Thus it has the potential to displace native species and becomes a safety risk along railway embankments because it rampantly grows there. Switzerland, Spain and France are trying to combat Buddleia, while in the USA its propagation is being observed critically and in New Zealand Buddleia is causing economic problems because it suppresses native vegetation.
In order to improve knowledge about the mechanisms responsible for the spread of invasive species, UFZ researchers compared ten populations of Buddleia in Germany with ten populations in its original homeland, the south west Chinese province Yunnan. Although the climatic conditions are more favourable in China, the bushes were larger in Germany and produced more and heavier seeds. "From the plants in the Chinese homeland, 15 percent of the leaves had been eaten by insects. By comparison, in Germany only 0.5 percent", reports Susan Ebeling from the UFZ. "The intruder is not yet on the menu for our insects. Because there are no relatives of Buddleia in Central Europe, the insects need longer to adapt." The two Asian insect species that were used in an attempt to control the bushes in New Zealand, are not yet present in Europe.
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 ones 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 completely and consequently become a problem.
"Its success obviously lies in cultivation. Through selection and hybridization it came to a genetic change, enabling the Oregon grape to grow larger in Europe than in its American homeland ", Dr. Harald Auge of the UFZ explains the research results. The biologist and his colleagues from Halle had collected seeds from Oregon grape plants in the USA, Canada, Germany and the Czech republic and had grown the plants under controlled conditions in a greenhouse.
Ornamental shrubs and cultivated plants constitute a majority of the alien plant species that have become a problem and are therefore referred to as biological invaders by specialists. Biological invasions caused by humans are one of the causes of the dramatic world-wide decrease in animal and plant species. According to a study conducted by the Federal Environment Agency, the economic costs of 20 alien species investigated, amounted to approximately 167 million Euros in the year 2002 in Germany. More recent figures are not yet available. In the near future, health care costs caused by the highly allergenic Ragweed are to be investigated by the UFZ and financed by the Federal Ministry of Research.Tilo Arnhold
Publications: Ebeling, S. K., Hensen, I., Auge, H. (2008): The invasive shrub Buddleja davidii performs better in its introduced range Diversity Distrib. 14 (2), 225-233 http://www.blackwell-synergy.com/doi/pdf/10.1111/j.1472-4642.2007.00422.x
Ross, C. A., Auge, H. (2008): Invasive Mahonia plants outgrow their native relatives. Plant Ecology (online first): DOI 10.1007/s11258-008-9408-z http://www.springerlink.com/content/j7q5304562j54674/
Ross, C. A., Faust, D., Auge, H. (2008): Mahonia invasions in different habitats: local adaptation or general-purpose genotypes? Biological Invasions (online first) DOI 10.1007/s10530-008-9261-y http://www.springerlink.com/content/y7002j2414271347/
Further information from:Helmholtz Centre for Environmental Research (UFZ) Dr. Harald Auge
Tilo Arnhold | UFZ Leipzig-Halle
The big clean up after stress
25.05.2018 | Julius-Maximilians-Universität Würzburg
Complementing conventional antibiotics
24.05.2018 | Goethe-Universität Frankfurt am Main
A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.
The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
24.05.2018 | Ecology, The Environment and Conservation
24.05.2018 | Medical Engineering
24.05.2018 | Physics and Astronomy