| Summary: | The chytrid fungal pathogens <i>Batrachochytrium salamandrivorans</i> (<i>Bsal</i>) and <i>B. dendrobatidis</i> (<i>Bd</i>) are driving amphibian extinctions and population declines worldwide. As their origins are believed to be in East/Southeast Asia, this region is crucial for understanding their ecology. However, <i>Bsal</i> screening is relatively limited in this region, particularly in hotspots where <i>Bd</i> lineage diversity is high. To address this gap, we conducted an extensive <i>Bsal</i> screening involving 1101 individuals from 36 amphibian species, spanning 17 natural locations and four captive facilities in the biodiversity-rich Guangxi Zhuang Autonomous Region (GAR). Our PCR assays yielded unexpected results, revealing the complete absence of <i>Bsal</i> in all tested samples including 51 individuals with <i>Bd</i> presence. To understand the potential distribution of <i>Bsal</i>, we created niche models, utilizing existing occurrence records from both Asia and Europe. These models estimated potential suitable habitats for <i>Bsal</i> largely in the northern and southwestern parts of the GAR. Although <i>Bsal</i> was absent in our samples, the niche models identified 10 study sites as being potentially suitable for this pathogen. Interestingly, out of these 10 sites, <i>Bd</i> was detected at 8. This suggests that <i>Bsal</i> and <i>Bd</i> could possibly co-exist in these habitats, if <i>Bsal</i> were present. Several factors seem to influence the distribution of <i>Bsal</i> in Asia, including variations in temperature, local caudate species diversity, elevation, and human population density. However, it is climate-related factors that hold the greatest significance, accounting for a notable 60% contribution. The models propose that the specific climatic conditions of arid regions, primarily seen in the GAR, play a major role in the distribution of <i>Bsal</i>. Considering the increased pathogenicity of <i>Bsal</i> at stable and cooler temperatures (10–15 °C), species-dependent variations, and the potential for seasonal <i>Bd</i>-<i>Bsal</i> interactions, we emphasize the importance of periodic monitoring for <i>Bsal</i> within its projected range in the GAR. Our study provides deeper insights into <i>Bsal</i>’s ecological niche and the knowledge generated will facilitate conservation efforts in amphibian populations devastated by chytrid pathogens across other regions of the world.
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