Responses of soil microbial diversity, network complexity and multifunctionality to environments changes in volcanic ecosystems

Volcanic ecosystems with unique and reduced-complexity environments are distributed globally, providing a platform for analysing the structure and function of natural microbial communities. This study aimed to explore the responses of soil microbial diversity, network complexity, and multifunctionality to environments changes in volcanic ecosystems. Actinobacteria (26.00-46.26 %), Acidobacteriota (5.68-19.10 %), and Crenarchaeota (4.71-18.65 %) were the dominant prokaryotic phyla. Furthermore, bacterial community was dominant over archaeal community. Among the fungal phyla, Ascomycota accounted for 60.30-94.45 % of the relative abundance. Fungal communities were more sensitive to the changes in biogeographical patterns in volcanic soils, while the prokaryotic community was more diverse. There were more biomarkers and functional compositions at the bottom of volcano sites than at the top (biomarkers: 85 vs. 39; functional group: 18 vs. 2; ecological guild: 8:1). The networks at the bottom of volcano had an increased complexity and connectivity (higher avgK and avgCC; shorter GD). The network in the top volcano was highly modularised. Three keystone species were observed only in this network. Soil chemical factors, directly and indirectly, influenced microbial structure and multifunctionality. Therefore, this study may provide key insights into understanding the assemblage of soil microbial communities in extreme environments, such as volcanic areas.