New Study Finds Deadly Fungal Disease in California Salamanders

SAN FRANCISCO— A scientific study published today revealed the emergence of a deadly fungus in two terrestrial salamander species in California, signaling a need to end the dangerous wildlife trade. This is the first study to document the disease in these species.

The findings, published in the academic journal Frontiers in Veterinary Science, showed that arboreal salamanders and Santa Lucia Mountains slender salamanders suffered high mortality rates when infected with the chytrid fungal pathogen Batrachochytrium dendrobatidis, or Bd. The authors found that social group size and interactions between species may contribute to disease spread.

“These findings are a grim reminder that the wildlife trade is extremely dangerous because it can spread deadly diseases far and wide,” said Tiffany Yap, D.Env/Ph.D., coauthor of the study and a senior scientist at the Center for Biological Diversity. “Amphibians already face numerous threats, from roads and habitat loss to disease and climate change. We need stronger policies to protect California’s native amphibian biodiversity against invasive species and disease spread.”

Spread through the wildlife trade, Bd is linked to the declines and extinctions of more than 200 amphibian species worldwide.

In California, mass die-offs due to Bd have been reported in frogs. But Bd’s threats to salamanders are less understood; salamanders are less visible because they’re nocturnal and live in burrows and under logs and rocks. Scientists worry that the full extent of Bd’s impacts on native salamanders is not known.

“I’ve personally witnessed local extinctions of mountain yellow-legged frog populations in the Sierra Nevada due to Bd. I lose sleep at night thinking salamanders could suffer the same fate without us even knowing,” said Vance Vredenburg, Ph.D., study coauthor and a professor at San Francisco State University. “We must do more to protect these populations before it’s too late.”

In 2015 the scientists and the Center called for action to protect North American salamanders from another deadly fungal pathogen, Batrachochytrium salamandrivorans, or Bsal, which has been devastating wild populations of fire salamanders in Europe. In response, the U.S. Fish and Wildlife Service placed temporary restrictions on salamander imports, though these restrictions do not encompass all disease threats.

The presence of Bd and Bsal in the pet trade is cause for concern in North America, where almost half of all salamander species live. Appalachia and the West Coast are salamander diversity hotspots. The introduction of disease adds to the many stressors amphibians already face and could cause serious harm to native biodiversity.

Amphibians are the most threatened vertebrate group, with more than 40% of species considered vulnerable, endangered or critically endangered by the International Union for Conservation of Nature. Researchers at the U.S. Geological Survey have found that amphibian populations in the United States are declining at an alarming rate of almost 4% per year.

The Center has worked to protect imperiled amphibians and reptiles throughout the United States and internationally. Read more about its campaign to address the amphibian and reptile extinction crisis.