The Spread of Batrachochytrium dendrobatidis Throughout the Americas and its Impact on Anuran Populations

Indianapolis, IN

Worldwide declines in amphibian populations have been attributed to such factors as habitat loss and deterioration. Batrachochytrium dendrobatidis (Bd), the chytrid fungus causing chytridiomycosis in amphibians, has also been implicated in the widespread decline of amphibians. Some studies suggest that Bd originated in Africa but quickly spread through the trade of infected anurans. Once introduced in an area, Bd's ability to live freely in water allows it to rapidly infect ecosystems via waterways. Using spatial analysis, we investigated the spread of Bd and its impact on native populations of Anurans in the Americas. We found that the fundamental niche of Bd spans almost the entirety of the Americas, appearing to be limited by cold temperatures and, to a lesser extent, high precipitation. The realized niche of the fungus has also rapidly increased in recent decades. Furthermore, our study indicates that the spread of Bd in the Americas began in large coastal cities and continued spreading inland, potentially aided by human transportation vectors such as roadways. As arguably one of the most virulent and catastrophic pathogens today, action and awareness about Bd is critical to the survival of today's amphibians.