Overview of chytrid emergence and impacts on amphibians

Abstract

Chytridiomycosis is an emerging infectious disease of amphibians that affects over 700 species on all continents where amphibians occur. The amphibian-chytridiomycosis system is complex, and the response of any amphibian species to chytrid depends on many aspects of the ecology and evolutionary history of the amphibian, the genotype and phenotype of the fungus, and how the biological and physical environment can mediate that interaction. Impacts of chytridiomycosis on amphibians are varied; some species have been driven extinct, populations of others have declined severely, whereas still others have not obviously declined. Understanding patterns and mechanisms of amphibian responses to chytrids is critical for conservation and management. Robust estimates of population numbers are needed to identify species at risk, prioritize taxa for conservation actions, design management strategies for managing populations and species, and to develop effective measures to reduce impacts of chytrids on amphibians.This article is part of the themed issue 'Tackling emerging fungal threats to animal health, food security and ecosystem resilience'.

Keywords: amphibians; biodiversity; chytrid fungi; disease; populations.

Figure 1.

The interaction of host ecology and evolution, fungal genotype and phenotype, and environmental conditions are thought to be key drivers of disease intensity, which ultimately determines individual mortality and host response to infection. (Online version in colour.)

Figure 2.

The evolving view of amphibian–chytrid interactions that includes responses of the entire amphibian community, multiple pathogens infecting a host community, and the effects of both abiotic environment and microbiome on host response. (Online version in colour.)