Synthesis of Batrachochytrium dendrobatidis infection in South America reveals patterns of host taxonomic and geographic risk
Claudio Soto-AzatMuseo del Jade
Claudio Soto-Azat, Mario Alvarado-Rybak, Ismael Barria-Oyarzo, Pablo Gonzalez, Andres Valenzuela-Sánchez, Sandra V. Flechas, Alexandra Peñafiel-Ricaurte, Andrew A. Cunningham, Leonardo D. Bacigalupe
The fungus Batrachochytrium dendrobatidis (Bd),which is a cause of amphibian chytridiomycosis, has been associated with alarming population declines and extinctions of amphibians worldwide. With its high amphibian species richness, South America has experienced devastating effects from this emerging disease. Here we provide a synthesis on the extent of Bdinfection across South America based on ~20,000 Bd-specific molecular diagnostic assays. We explored potential signatures of Bdoccurrence associated with amphibian taxonomy, country of origin and species conservation status. We show that Bdis widespread in South America, with a continental prevalence of 20.8%. Among the taxa exhibiting the highest Bdprevalence are amphibians in the families Ranidae, Telmatobiidae, Calyptocephalellidae, Cycloramphidae and Pipidae (range: 31.453.3%), reflecting their close association with aquatic environments and therefore higher contact with the infective stage of Bd. Low Bd occurrence in terrestrial amphibians, however, does not necessarily indicate protection, as groups of amphibians exhibiting unusually low Bdprevalence are also among the amphibians in which lethal chytridiomycosis has been described in the literature (e.g. Atelopus, Rhinodermaand Eleutherodactylus) (07.5%). Among the countries showing higher than expected occurrence of Bdwere Bolivia and Brazil (39.5 and 64.0%, respectively), reflecting Bdhighly favorable habitats in the high Andes and the Atlantic forest. Many widespread and abundant species exhibited highBdprevalence (e.g. the invasive Lithobates catesbeianusand Xenopus laevis) and we propose that these could be used as sentinels for Bdmonitoring. Also, is essential to understand the potential role of these species as reservoirs, vectors or spreaders, that can be subjected to management. Our results inform guidance on the prioritization of conservation actions to prevent further biodiversity loss due to chytridiomycosis in the worlds most amphibian diverse region.