Invasive fungus expected to arrive in North America via global trade
Global trade in salamanders is seen as a big threat to wild salamanders in the United States, according to the U.S. Geological Survey.
The agency highlighted the potential risks in a recent report, highlighting that cooperative research and management efforts are needed to develop and implement effective pre-invasion and post-invasion disease-management strategies if Batrachochytrium salamandrivorans (Bsal) enters and affects salamanders within the United States.
The deadly fungus has already caused population crashes in wild European salamanders could emerge in the United States and threaten already declining amphibians here, according to the report. Bsal is just one of the many emerging invasive species threats in the era of globalization, and the USGS report helps how preventive strategies may be able to at least slow the spread of new pathogens.
“Based on the kinds of species affected and the fact that the United States has the highest salamander diversity in the world, this new pathogen is a major threat with the potential to exacerbate already severe amphibian declines,” said Evan Grant, a USGS wildlife biologist and lead author of the USGS report. “We have the unusual opportunity to develop and apply preventative management actions in advance.”
A new rule, authorized under the Lacey Act, listing 201 salamander species as injurious, could help reduce the likelihood of introduction of Bsal into the country. So far, the deadly fungus hasn’t been found in wild U.S. salamander populations, but scientists caution it is likely to emerge here because of the popularity of captive salamanders as household pets, in classrooms and in zoos. The captive amphibian trade is a known source of salamanders afflicted with the fungus.
Amphibians are the most endangered groups of vertebrates worldwide, with another fungus closely related to Bsal (Bd) contributing to amphibian die-offs and extinctions global over the last two decades.
Bsal was first identified in 2013 as the cause of mass wild salamander die-offs in the Netherlands and Belgium. Captive salamander die-offs due to Bsal have occurred in the United Kingdom and Germany. Scientists believe Bsal originated in Asia and spread to wild European populations through the import and export of salamanders.
The USGS brought together scientists and managers from federal and state agencies that oversee resource conservation and management to identify research needs and management responses before Bsal arrives and becomes entrenched in the country. USGS, the USFWS, U.S. Forest Service, U.S. Department of Defense, National Park Service, zoos, and U.S. and international universities participated in the Bsal workshop.
Key findings in the report include:
- Bsal is highly likely to emerge in U.S. populations of wild salamanders through imports of potentially infected salamanders.
- Management actions targeted at Bsal containment after arrival in the United States may be relatively ineffective in reducing its spread.
- A coordinated response, including rapid information sharing, is necessary to plan and respond to this potential crisis.
- Early detection of Bsal at key amphibian import locations, in high-risk wild populations, and in field-collected samples is necessary to quickly and effectively implement management responses.
“The increasing pace of global commerce and emergence of new infectious diseases put vulnerable native wildlife populations at risk for extinction,” said Grant. “Managing disease threats to the 191 species of U.S. salamanders is essential for the global conservation of salamanders.”
Grant said the process by which Bsal research and management needs were identified could be adapted for future infectious disease threats to wildlife.