The flatworms of the Obama nungara species, which live in Argentina, have spread almost throughout France, becoming the most dangerous representative of this category of invertebrates introduced to Europe by humans.
“These worms are now found in 72 out of 96 French departments, especially on the Atlantic coast, near the border with Spain and the Mediterranean Sea. Our observations indicate that Obama nungara can be classified as an extremely invasive worm species that will soon become the most significant threat to the soil fauna of Europe, "the researchers write.
The so-called invasive species of animals, penetrating new territories and continents thanks to humans, several decades ago became one of the main problems for the environment.
In particular, the penetration of Brazilian fire ants into the United States in the middle of the last century led to the fact that several species of snails disappeared from the face of the Earth, and the number of other species of invertebrates and even mammals decreased significantly. In turn, the African fungus Batrachochytrium dendrobatidis, which has penetrated Europe, America and Asia, has destroyed 90 species and millions of amphibians over the past two decades.
Representatives of the flora are also affected by similar problems. For example, the spread of the East Asian bacteria Candidatus liberibacter now threatens the extinction of citrus plants around the world, and the Colorado beetles that entered Europe in the 1960s have become one of the main problems for collective farmers in the Soviet Union and farmers in Western countries.
Invertebrate colonizers
A group of biologists led by Jessica Thevenot discovered another new threat of this type, studying the regions of France where the Obama nungara worm, introduced to Europe in 2013 from Argentina, is found.
To carry out these observations, the scientists gathered a group of several dozen volunteers who lived in different regions of the country and told them what kind of flatworms they saw during their hikes in nature or inside the cities and villages where they lived.
In total, amateur naturalists collected over five hundred photographs and tissue samples of the Obama nungara, allowing Theveno and her team to accurately map the range of these invertebrate predators and estimate their population density.
As it turned out, these flatworms were found in virtually all low-lying areas of France and were absent only in those regions whose height above sea level exceeded 500 meters. In addition, in recent years they have managed to penetrate the territory of Spain, Switzerland, Belgium and some other countries.
The researchers estimate that the Obama nungara significantly outnumbered other invasive flatworms, Platydemus manokwari and giant hammerheads, brought to France along with plants from Papua New Guinea and East Asia.
The high numbers of these worms, their lack of natural enemies, and their large appetites, according to Theveno and her colleagues, will make Obama nungara one of the main threats to European soil ecosystems in the coming years.