Substrate and spatial variables are major determinants of fungal community in karst caves in Southwest China

Aim Previous studies primarily based on the culture method have revealed that caves host a high fungal diversity and that exogenous carbon sources influence fungal communities. Here, we assess the fungal diversity and distribution patterns in karst caves in Southwest China and reveal the major factors that shape the fungal communities. Location Southwest China. Methods Samples of air, rock, sediment and water were collected from eight caves in Southwest China. Using high‐throughput sequencing of the internal transcribed spacer 1 region of fungal rDNA, we examined the cave fungal communities in Southwest China and studied their correlations with potentially influential factors, such as substrate, cave, location and environmental variables. Results Approximately 10,000 fungal operational taxonomic units (OTUs) spanning 15 phyla were obtained. The highest diversity genus was Penicillium, while Mortierella had the highest relative abundance. Compared with air and rock samples, sediment and water samples harboured higher diversity and distinct communities. Substrate and cave were revealed to be the key determinants of the fungal communities in caves. Sample location and sampling distance from the entrance had more significant impacts on rock and sediment communities than on air and water assemblages. The fungal assemblages in air and water samples from the cave and outside cave environments were similar, while those of rock and sediment samples were significantly different. Main conclusions Our results indicate that sediment and water harboured higher fungal diversity than air and rock, and substrate and spatial variables are key determinants of fungal communities in caves.