They are poisonous or voracious: THESE pests annoy Berlin
Many of them have come a long way. The animal and plant immigrants that are spreading more and more in Berlin. Not all newcomers are as harmless as they first appear. With their great hunger they destroy ecosystems. With their gifts they can be a danger to humans.
Berliners became really aware of the animal immigrants when, in 2017, American swamp crayfish were sighted on meadows and paths in the Tiergarten for the first time. The American cancer, as it has been popularly known since then, has caused a lot of excitement.
Presumably, the offspring of abandoned animals had multiplied unnoticed before hunger or lack of space drove them out of the park waters. Every summer, the crab invaders, which are actually native to the southern United States and northern Mexico, are caught. A further spread should be prevented and the multiplication should be slowed down. Because the voracious and migratory animals are a threat to native species and ecosystems.
Pests in Berlin: The giant hogweed is even poisonous
According to the Federal Agency for Nature Conservation, around 900 foreign species have settled and spread permanently in Germany. Also in Berlin, where some foreign species are spreading, especially from the plant kingdom, which are dangerous for humans.
For example, the giant hogweed: its juice contains the toxin furocoumarin, which triggers allergic reactions even in small amounts. Depending on the intensity of the contact and personal constitution, the symptoms range from reddening of the skin and itching to swelling, fever and circulatory problems. You should look carefully when walking through parks and looking for a spot to sunbathe.
The tree of heaven, which comes from Asia and spreads out in green areas, is not entirely without. It crowds out other plant species. It also gets stuck in every crack in the concrete, making streets and walls dangerous. Touching it can cause allergies in people. In contrast, the narrow-leaved waterweed is still harmless. The plant, popular with aquarium owners, quickly spreads in the subsoil of the lakes, forming quasi-underwater forests there.
Egyptian goose displaces native species
Also on the list of animal invaders is the Egyptian goose, which is actually in Egypt. Nabu experts suspect: These geese come from breeds in Great Britain and Holland that escaped from their captivity or were abandoned. Experts fear that the Egyptian geese could displace native wild bird species.
Real animal tormentors in the capital region are raccoons and coypu. They don’t just rummage around in our garbage cans or nest on house roofs and cause chaos there. Raccoons and Co. also spread diseases that are dangerous for domestic animals (rabbit plague, distemper).
The American raccoon feels really at home in Berlin. More than 800 families live mainly in the outskirts of Spandau, Reinickendorf, Marzahn, Treptow and Köpenick.
66 animal and plant species are on a list drawn up by the EU Commission, the so-called Union list of invasive species. The member countries must prevent the introduction of these species and stop their unchecked spread once they have arrived. That also applies to Berlin.
“In the case of species that are not yet native here, you have a very good chance of keeping them away,” says Ingolf Kühn from the Helmholtz Center for Environmental Research (UFZ). “In the case of species that are already established, such as the swamp crabs or the giant hogweed, it can no longer be determined. Then it is particularly important to contain the stocks and keep the species away from sensitive areas such as nature reserves.”
Fighting the pests is a Sisyphus task
In Berlin, the senate administration has commissioned a fisherman who empties the traps laid out at least twice a week during the high season and sells the animals to restaurateurs, among others.
However, it is rarely possible to use a knife and fork to combat invasive species – and combating them is often tantamount to a Sisyphus task. “Often there is not enough capacity for this,” says Sebastian Kolberg, consultant for species protection at Nabu. “The lower nature conservation authorities simply lack the financial and human resources.”
“Relying uncompromisingly on the expulsion of an invasive species is often not effective,” says Kolberg. Putting all households on the management of one type of conflict is not a sustainable strategy. It often makes more sense to strengthen the health of the ecosystem as a whole.
“Especially with the plants, many of the neophytes do not cause any problems, on the contrary,” says wildlife expert Derk Ehlert from the environmental administration. “Our parks would probably have far fewer species if there were no neophytes.” In general, nature is constantly changing – and so is the assessment of animal and plant species.
“The tree of heaven, which originated in China, has been planted here for around 250 years and has been cherished and cared for as a beautiful city tree for a long time,” says Ehlert. “For about 80 years, the species has been spreading massively because the winters have become warmer and the young trees, which are sensitive to frost, are increasingly surviving.” Today, the plant, as described, is a problem and officially undesirable.
Pests: Once wanted, now unwanted
Many of the species considered problematic today were once deliberately introduced: the raccoon, for example, as a source of fur, the Asian ladybird for biological control of pests. Today they are one of the species that can no longer be driven out.
The situation is unlikely to improve with climate change. According to UFZ researcher Kühn, frost-loving species could become fewer. However, the majority of the introduced species come from warmer countries and will benefit from the expected changes.
“Fend off the beginnings,” says wildlife expert Ehlert. “Once a species has established itself, there is often little opportunity to get rid of it.”