Chytrid fungus in threatened Brazilian amphibians: A focus on island populations

Abstract

The chytrid fungus Batrachochytrium dendrobatidis (Bd) poses a serious threat to amphibians worldwide, with itsemergence linked to population declines across numerous species. Thus, detecting Bd infection and understandingthe patterns within different hosts are essential for evaluating risks, particularly for endemic andthreatened species. Therefore, we reviewed and provided novel information on Bd infections in endangeredBrazilian amphibians, focusing on three island-endemic species. Additionally, we analyzed Bd occurrence datafrom studies conducted in the past 20 years on threatened Brazilian amphibians and supplemented these findingswith additional records from museum specimens. Our results indicate that Bd is widespread among Brazil’sthreatened amphibian species but exhibits varied infection patterns. Among the threatened island species, whileCycloramphus faustoi and Ololygon alcatraz exhibited no detectable infections in our fresh samples, Ololygonfaivovichi showed high prevalence and infection loads. The detection of Bd in endemic species, particularly invulnerable island populations with restricted distribution, highlights the urgent need for continued monitoringand proactive conservation actions. These findings are critical for informing the development of long-termmanagement strategies that integrate Bd detection, treatment, and eradication into conservation planning tosafeguard Brazil’s endangered amphibians and ecosystems.