Introduced species often threaten native fauna and flora. A study now shows how the pet trade is fueling this process. An underestimated problem: ants.

The international trade in ants as pets has been booming for years. A research team from Switzerland is now warning that this could threaten biodiversity in many places. Because those potentially invasive species that spread easily in non-native regions are more frequently traded globally with success, the scientists write in the journal »PNAS« .

Cleo Bertelsmeier and Jérôme Gippet from the Institute for Ecology and Evolution in Lausanne wanted to work out in a meta-analysis how often invasive species are offered and sold in the animal trade worldwide. They have listed thousands of different species, from mammals to fish to insects. They calculate that more than twelve percent of the species traded are invasive species. The problem becomes clear, among other things, with the ants: Invasive species are not only sold more often than others, they are also represented more than six times more frequently in the pet trade than corresponds to the natural proportionate distribution.

"Our analysis shows an emerging and rapidly growing invasion path for ants," the researchers write: "We assume that the pet trade in ants will contribute to the spread of invasive species in the future." Their analysis shows that the sales success and robustness as a commodity correlate with the ability to survive in foreign habitats: Here, for example, there are larger generalists with larger workers and several queens in the nest. Of the 57 species of ants found by researchers on trading platforms, 13 of the 19 most invasively threatening species of ants identified by the International Union for Conservation of Nature (IUCN) are. Species like the red fire ant (Solenopsis invicta) , for example, are becoming a notorious invader, gladly sold by dealers.

The problem with the animal trade goes beyond ants: Invasive species are also clearly overrepresented in mammals, birds, reptiles, amphibians and fish. "Our results underline the urgent need to regulate the global trade in living animals - including invertebrates - internationally," the scientists write. The current rules are inadequate.

According to the Federal Agency for Nature Conservation (BfN), invasive species are those that spread through human influence in regions in which they were not previously native, be it in luggage and goods, for example on board ships or through the animal trade. They would often have undesirable effects on other species, communities or biotopes because they compete with native species for habitat and resources and can also displace them.

In general, species with large areas of distribution and few special demands on their environment spread more often where they are not actually native, as the Lausanne study says. The fact that they are above average in the pet trade could be due, on the one hand, to the fact that traders can get hold of these species more easily because they are widespread. On the other hand, they may also be more attractive for buyers because they are easier to care for than species with special needs.

Source: spektrum