How the weather can influence a deadly frog fungus

The chytrid fungus has devastated amphibian populations worldwide, causing the decline of at least 500 species. While some Australian frog species have been impacted heavily by this disease, others, like Western Australia’s motorbike frog, appear to have fared better.

To investigate the prevalence of the chytrid fungus in populations of motorbike frogs, researchers from the CAUL and TSR Hubs studied environmental conditions at 45 wetlands on the Swan Coastal Plain and swabbed almost 1200 frogs.

The results, published in a new report, show that the chytrid fungus is widespread and infects motorbike frogs throughout the area. However, the prevalence of the chytrid fungus in frog populations varies spatially and temporally with variation in environmental conditions at a site and across seasons. During the winter, 57% of the frogs sampled were infected with chytrid, but in the summer this dropped to only 4%. Hot weather (above 28 oC) was strongly linked with low infection rates, and the salinity of wetlands was also found to inhibit chytrid.

Further research is needed to understand why motorbike frogs are still thriving while two closely related species (growling grass frog and green and golden bell frog) are declining, when all three species are exposed to the chytrid fungus, habitat loss and other threats.

Photo by Kirsten Parris

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