The Nungara flatworm has gained a foothold in this country and is threatening our ecosystem. But what is even more worrying is that it is multiplying inexorably.
It came to Europe from South America via the soil of potted plants - hopefully not to stay: the Nungara flatworm (Obama nungara) has the best conditions to develop into an invasive species without predators in Germany. The carnivorous predator feeds on earthworms, snails and other flatworms, among other things. This could be dangerous for native species and therefore also beneficial insects, so you have to keep an eye on the species and it is best to report a find in your own garden or on another green area.
If the flatworm spreads, native earthworms are at risk
As the Federal Agency for Nature Conservation explains in a script, a Nungara flatworm was detected in Germany for the first time in 2019 - in a potted plant in the Munich-Nymphenburg Botanical Garden. Outdoor discoveries in public green spaces in Bavaria and Baden-Württemberg followed in the years that followed. The worm is already very widespread in France. Since it can also reproduce asexually via division, the genus does not even depend on a conspecific.
Some hobby gardeners may be happy about the prospect of Obama now getting rid of the snails in the bed. But these could also include the useful tiger snail or protected species such as the Roman snail. The impact could be even greater on native earthworms, which are very important for good soil quality. Since the flatworm tastes too bitter even for predators such as birds or hedgehogs, it can reproduce particularly well.
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How to recognize and report the flatworm
The worm, which is around seven centimeters long and up to five millimeters wide, has a golden yellow basic color with numerous brown dots. The abdomen of the very flat worm is white-gray. Even though the worm has a slimy back and likes moist habitats, unlike the similar leech, it is clearly a land animal, according to a research report in the science magazine
Biology in Our Time.
Since the risk posed by the flatworm cannot yet be fully assessed, you should check the root ball of purchased plants. In the garden, like snails, it could hide in the compost and under dead wood, leaves, flower pots or covers - anywhere it is dark and damp. It also feels very comfortable in greenhouses. Anyone who finds such a brown flat worm should capture the animal with tweezers, photograph it and kill it in a container with soapy water. You should also report the animal to the German Nature Conservation Association or via the specialist portal “iNaturalist”.