This aggressive strain of the fungus has been detected in Serra da Estrela and elsewhere across the Iberian Peninsula.
Since the 1990s the link between chrysoid (Batrachochytrium dendrobatidis), a microscopic fungus, and the decline of several amphibian species worldwide has been debated.
The fungus infests the skin of frogs, toads and other amphibians causing a disease called chytridiomycosis.
In more susceptible species, this fungus has been responsible for numerous episodes of mass mortality.
However, it was not known where and when this fungus and its more aggressive lineage originated.
The results of the now-published study, which involved an international team of more than 50 researchers from 38 institutions, reveal that the strain emerged in Southeast Asia, namely on the Korean peninsula.
“This is an issue that has been at the centre of staggering debates over the last two decades, with diverse suggestions on the table such as South Africa, North and South America or even Japan”, explains Gonçalo M. Rosa, researcher of the cE3c - Centre for Ecology, Evolution and Environmental Change (Lisbon University’s Faculty of Sciences) and the Zoology Institute of London (UK).
In Portugal, the fungus was associated with mass losses for the first time in 2009, in Serra da Estrela, where Gonçalo M. Rosa has since established a monitoring programme.
“Toad populations were the most affected, especially in the higher areas of Serra da Estrela where, in some ponds and lakes, they were simply no longer seen or heard”, the researcher explains.
The results of this study, coordinated by Imperial College London, indicate that the movement of amphibians caused by human activity - for example through pet trade or for gastronomic purposes - will have made a significant contribution to the global spread of this strain.
The authors recommend greater control over trade in amphibians from Asia, as well as greater attention to hygiene and biosafety measures in their transport, due to the high risk of export of previously unknown strains outside the region.