Between 1986 and 2020, imported amphibians and reptiles have burdened the global economy with a cost of approximately 16.5 billion euros. As an international working group led by Phillip Haubrock from the Senckenberg Research Institute and Nature Museum Frankfurt reports in the journal "Scientific Reports", there are mainly two species that cause the mentioned costs: the Brown Night tree snake (Boiga irregularis) and the North American bull frog (Lithobates catesbeianus). The animals decimate native species, which in turn destabilizes ecosystems, leads to the spread of diseases among animal species and causes crop losses.
For their analysis, the researchers have evaluated information from the Invacost database, which contains scientific studies and documents from governments, universities and NGOs. Haubrock and his team came to several results: With a financial loss of around 16.5 billion euros, around 6.1 billion euros are eliminated to invasive amphibians and around 10.1 billion euros on limited reptiles. A good 200 million euros go back to both groups of animals. For frogs, toads or amphibians, the costs arise from combating the animals. However, reptiles are increasingly causing damage, for example on fields.
The distribution of costs varies worldwide. Oceania and the islands in the Pacific carry about 63 percent, Europe about 35 percent and North America two percent.
Where the ox frog and the night tree snake were brought in
On the Western Pacific island of Guam, for example, there are more than 10,000 specimens of the Brown Night Tree snake per square kilometer. During the Second World War, US troops had brought in the reptile. After a few years, the snakes ate numerous native bird species, which are now extremely reduced or even extinct. In addition, the vipers on Guam cause a number of power outages, which in turn generates repair costs. In Europe, on the other hand, amphibians are more likely to be recorded. The fight against the North American bullfrog alone consumes 95 percent of all spending there.
According to a press release, Haubrock emphasizes that the calculations of his team would show "for the first time the worldwide costs through the herpeto sauna". However, the biologist assumes more damage than is previously recorded. "We also assume that the invasion rates will increase in the future-an increase in economic costs will follow," says the Senckenberg researcher. In his opinion, the expenditure could be reduced if the transport of amphibians and reptiles were more limited and prevented worldwide.
