Chytridiomycosis in Sri Lanka: Predicting the future of a global amphibian hotspot

Chytridiomycosis, caused by Batrachochytrium dendrobatidis (Bd), constitutes a major threat to many amphibian species worldwide. Predicting the species and regions of highest geographical risk is critical for the early detection and mitigation of chytrid emergence.In this study, using a niche modelling approach, the most conducive habitat for Bd within Sri Lanka (a high-risk zone) was modelled. The distribution of 69 amphibian species was then modelled and their overlap with the high-risk zone (area(Bd)) was calculated.Using area(Bd) and a biotic index (BI), created using ecological traits of each species, a risk index (RI) was calculated. Using this RI, a high-risk species index (HRSI) was developed to identify the species most at risk.The results indicate that the high elevations of Sri Lanka (>600 m a.s.l.) are highly conducive for Bd. The HRSI includes 35 species, with Minervarya greenii being the species most at risk. All species in the HRSI are globally Critically Endangered (n = 14) or Endangered (n = 21).We propose active conservation measures such as the routine monitoring of HRSI species and other proactive measures to identify and prevent the spread of Bd. We believe our findings would promote the establishment of pre-emptive mitigation measures both within Sri Lanka and elsewhere, to counter the threat of chytridiomycosis and to conserve amphibian species.