Brown rat, ragweed and the Asian ash splendor beetle have one thing in common: they are all not originally native to Europe – and they are among the five most expensive invasive species in Europe. Since 1960, such non-native species have caused costs of more than 116 billion euros in Europe, in Germany it is more than eight billion euros, according to researchers.
Many animals and plants are now spreading where they were not previously native. Most of them are harmless and pose no threat to humans or native ecosystems. Others, however, are more problematic in terms of immigration or introduction. These so-called invasive species have no natural enemies in their new habitat and are often superior to their domestic competitors. Therefore, they are spreading rapidly and displacing other species.
Studies show that the number of these bio-invaders is increasing rapidly – for a variety of reasons. “There are many reasons for the immigration and introduction of invasive species: tourism, global warming, trade, traffic. In its central location, Germany, for example, operates an intensive trade in goods with other countries, which is certainly one of the main reasons for the spread and introduction of alien species, ”explains Phillip Haubrock from the Gelnhausen branch at the Senckenberg Research Institute and Nature Museum in Frankfurt.
More than 116 billion euros in damage since 1960
Haubrock and his team have now investigated in more detail what damage and thus also the costs this bioinvasion and its consequences entail for Europe and Germany. To do this, they evaluated the entries in the global InvaCost database, a central platform that records economic damage caused by alien species from all over the world. “For the first time, we have quantified the costs that have arisen from invasive species in European countries in a comprehensive and detailed manner, and have observed their trends over a period of 60 years,” explains Haubrock.
The result: In the period from 1960 to 2020 in European countries alone, damage worth more than 116.61 billion euros was caused by non-native species. The invasive species caused most of the costs in agriculture and forestry, with Great Britain, Spain, France and Germany being hardest hit, as the team reports. The brown rats, the ragweed (Ambrosia artemisiifolia), the wild rabbit, the Asian ash beetle and the flatworm Gyrodactylus salaris are among the most serious bio-invaders. “The brown rat alone has owed costs of around 5.5 billion euros in Europe within 60 years,” says Haubrock.
Germany is also badly affected
In Germany, too, the damage caused by non-native species is considerable: Overall, the economic costs between 1960 and 2020 are estimated at 8.21 billion euros. A large part of this sum is based on estimates for a few species such as the American bullfrog, the late blooming bird cherry (Prunus serotina) as well as the muskrat and the American mink. However, the actual damage caused by invasive species could be significantly higher for us, as the scientists explain.
“In Germany, according to the current data situation, of the almost 200 species listed as invasive, only 28 species cause the corresponding costs. Species such as the North American raccoon – which has been proven to have already caused damage in Germany – are not yet included in the bill at all, ”says Haubrock. In addition, it is difficult to quantify indirect costs, for example due to the impairment of human health or the displacement of native species. “Not all invasive species cause economic damage, but the resulting costs are probably extremely underestimated and are probably many times higher,” says the researcher. “The invasion rates continue to rise and we have to assume that the economic costs will also follow this trend.” The team has already found that the costs of invasive species have increased tenfold per decade.
Source: Senckenberg Research Institute and Nature Museums; Technical article: NeoBiota