Europe’s largest and best known salamander species, the fire salamander, is falling victim to a deadly fungus, and new research is making scientists more pessimistic about its future. A 2-year study of a population in Belgium, now entirely wiped out, has revealed that these amphibians can’t develop immunity to the fungus, as was hoped. To make matters worse, it turns out the fungus creates a hardy spore that can survive in water for months and also stick to birds’ feet, offering a way for it to spread rapidly across the continent. Two other kinds of amphibians, both resistant to the disease, also act as carriers for the highly infectious spores.
“This is terrible news,” says geneticist Matthew Fisher of Imperial College London, who studies the fungus but was not involved in the new research. “This isn’t a problem that’s going to go away. It’s a problem that’s going to get worse.”
The pathogen, Batrachochytrium salamandrivorans (Bsal), is a chytrid fungus, a type that lives in damp or wet environments and typically consumes dead organic matter. Bsal infects and eats the skin of salamanders, causing lesions, apathy, loss of appetite, and eventually death. Over the past few decades, a related fungus, B. dendrobatidis (Bd), has struck hard at amphibian populations around the world, particularly in the Americas, Australia, Spain, and Portugal. More than 200 species of frogs and toads are thought to have gone extinct, including many kinds of Costa Rica’s striking stream-breeding toads.
Bsal was identified in a nature reserve in the Netherlands in 2013 after fire salamanders started dying with ulcers and sores similar to those caused by Bd. Fire salamanders (Salamandra salamandra) grow up to 35 centimeters long, can live more than 40 years, and hunt insects and other small prey in forest streams. Their bright yellow spots warn predators of poison around their head and back. In the Dutch nature reserve, the population plummeted 99.9%. The fungus is thought to have arrived in Europe via salamanders or newts imported from Asia for the pet trade. Bsal has since been found in Belgium and Germany in both fire salamanders and alpine newts.
As soon as Bsal was spotted in Belgium in April 2014, veterinarian An Martel of Ghent University in Merelbeke, Belgium, and her colleagues began visiting every month to track the population. About 90% of the fire salamanders died within 6 months, and after 2 years all were gone. The fieldwork revealed that adult animals were more likely to get infected, which makes sense because they are in closer contact with each other—through fighting for mating and breeding, for example—than are juveniles. But the death of these adults means that the population…