The South American giant rodents have already established themselves in many European waters and that was apparently just the beginning: The nutrias will probably spread more and more, according to a study. Accordingly, there are still many potential habitats for the problematic exotic species, which are not afraid of being close to humans. In addition, the north is increasingly becoming a suitable habitat for the invasive species as a result of climate change, the researchers report.
Too big for a rat, but it can’t be a beaver either – if you see a strange rodent on a European waterfront, you are probably dealing with a nutria (Myocastor coypus). At first glance, these animals resemble our largest native rodent, but their tails are round and do not form a flattened oar. Instead, they have webbed feet that make them easy to move about in the water. The relatives of the guinea pig, which are up to 70 centimeters long and weigh nine kilograms, originally come from South America.
Furry South Americans in their sights
There the Nutrias colonize the bank areas of waters in the subtropical and temperate climate zones. They feed mainly on plants, but also do not disdain small aquatic animals. Rodents came to Europe as early as the end of the 19th century: They were bred in fur farms for their fur. Liberated or escaped animals then proved to be able to survive in European nature and were able to form colonies in many places.
Today nutrias are already widespread in many European countries. So also in Germany, where they can be found in all federal states. Depending on the local conditions, the Nutrias live in reed nests or dig caves in the embankments. Since they are hardly shy of people, they have also been able to establish themselves in urban areas. The nutria is already on the list of invasive species in Europe with the aim of preventing further spread. However, so far there have been hardly any systematic studies of their occurrence and further spread potential.
Researchers at the University of Vienna have now devoted themselves to this topic. To this end, they collected information on the occurrence of the species from all over Europe and, based on the characteristics of the habitats, identified the conditions in which the nutrias can hold up particularly well. Then they recorded where the rodents could find these conditions, but not yet exist – i.e. the spread potential of the invasive species.
Great potential for spreading
“It was shown that the currently known occurrences do not even cover half of the potentially suitable area in Europe and that a further significant spread can therefore be expected in the next few years”, co-author Franz Essl sums up the result of the study. “In the course of climate change and milder winters, northern regions are also becoming increasingly nutria-friendly. How the species will react to drier and hotter conditions in the south, however, should be researched in more detail, ”says the first author of the study Anna Schertler. It seems clear, however, that nutrias will hardly be able to be driven out of Europe and could increasingly become a problem. “With high population densities, considerable damage occurs to bank reinforcements and in agriculture, for example in corn fields. Natural habitats and rare plant species can also be damaged, ”says Schertler. Nutrias are also potential carriers of various diseases, such as toxoplasmosis.
It therefore makes sense to focus on reducing population densities and the associated spread and damage, say the scientists.
According to them, awareness-raising work is particularly important in urban areas. Because there the cute rodents are apparently also fed by animal lovers, which leads to a strong increase in the population. “There are also many cross-border deposits, for example along border rivers. Coordinated international cooperation is essential here, ”says Anna Schertler.
Anyone who comes across the furry exotic while taking a walk can also make a contribution to further research into the distribution of nutria in Europe, say the scientists: Via the smartphone app “NaturaList“You can easily report a sighting with the appropriate location information.
Source: University of Vienna, specialist article: NeoBiota, doi: 10.3897 / neobiota.58.33118