‘Alien’ fungus threatens European salamanders
Europe’s salamanders could be decimated by a flesh-eating alien species that has already wreaked havoc in some parts of the continent, scientists said in a study published Wednesday.
Researchers who examined the impact of the alien invader — a fungus native to Asia — on fire salamanders in Belgium and the Netherlands found it to be lethal to the amphibians and almost impossible to eradicate.
The study published in the journal Nature Research provides a drastic warning to North America, where the fungus hasn’t yet taken hold.
“Prevention of introduction is the most important control measure available against the disease,” said An Martel, a scientist at the University of Ghent, Belgium, who co-authored the study.
The B. salamandrivorans fungus, which likely was imported to Europe by the pet trade — causes skin ulcers, effectively eating the salamander’s hide and making it susceptible to secondary bacterial infections.
Martel and her colleagues began studying the effect of the fungus in early 2014, four years after it was first recorded in Europe.
Within six months, the population of fire salamanders at the site in Robertville, Belgium, had shrunk to one-tenth of its original size. Two years later, less than one per cent of the distinctive yellow-and-black patterned amphibians had survived, according to the study.
Sexually mature salamanders appeared to be particularly prone to becoming infected with the fungus due to their contact with other individuals, preventing them from producing new generations. Furthermore, researchers found the fungus was able to form spores with thick walls that allowed it to survive for longer and spread further, including on the feet of water birds. Other amphibian species, including newts and toads, were also susceptible, either making them carriers of the fungus or ill themselves.
Finally, infected animals failed to develop an immune response that might allow some of the salamander population to survive and ultimately prevail against its new foe, which has already been detected in 12 populations in the Netherlands, Belgium and Germany. Conservationists in the United States are already monitoring wetlands for signs of the fungus.
“For highly susceptible species like fire salamanders, there are no available mitigation measures,” said Martel. “Classical measures to control animal diseases such as vaccination and repopulation will not be successful since there is no immunity buildup in these species and eradication of the fungus from the ecosystem is unlikely.”
In a separate comment published by Nature, Matthew C. Fisher, an expert in fungal epidemiology at Imperial College London who wasn’t involved in the study, backed the researchers’ suggestion that the only way to save Europe’s salamanders may be to keep a healthy population in captivity — at least until a cure is found. “It is currently unclear how (the fungus) can be combated in the wild beyond establishing ‘amphibian arks’ to safeguard susceptible species as the infection marches relentlessly onwards,” said Fisher.