Xuan Liu
(Ed.)
Aim: Amphibian populations are threatened globally by anthropogenic change and
Batrachochytrium dendrobatidis (Bd), a fungal pathogen causing chytridiomycosis disease to varying degrees of severity. A closely related new fungal pathogen,
Batrachochytrium salamandrivorans (Bsal), has recently left its supposed native range
in Asia and decimated some salamander populations in Europe. Despite being noticed
initially for causing chytridiomycosis-related population declines in salamanders, Bsal
can also infect anurans and cause non-lethal chytridiomycosis or asymptomatic infections in salamanders. Bsal has not yet been detected in the United States, but given
the United States has the highest salamander biodiversity on Earth, predictive assessments of salamander risk to Bsal infection will enable proactive allocation of research and conservation efforts into disease prevention and mitigation.
Location: The United States, Europe and Asia.
Methods: We first predicted the environmental suitability for the Bsal pathogen in
the United States through an ecological niche model based on the pathogen's known
native range in Asia, validated on the observed invasive range in Europe using bioclimatic, land cover, elevation, soil characteristics and human modification variables.
Second, we predicted the susceptibility of salamander species to Bsal infection using
a machine-learning model that correlated life history traits with published data on
confirmed species infections. Finally, we mapped the geographic ranges of the subset
of species that were predicted to be susceptible to Bsal infection.
Results: In the United States, the overlap of environmental suitability and susceptible
salamander species was greatest in the Pacific Northwest, near the Gulf of Mexico,
and along the Atlantic coast, and in inland states east of the Plains region.
Main Conclusions: The overlap of these metrics identify salamander populations that
may be at risk of developing Bsal infection and suggests priorities for pre-emptive
research and conservation measures to protect at-risk salamander species from an
additional pathogenic threat.
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