Land use and soil texture drive shifts in communities of soil biota across natural and anthropogenic tropical ecosystems

Abstract

Tropical ecosystems host immense aboveground biodiversity, but the diversity and dynamics of soil biota across different habitats and land-use types remain largely unexplored. We conducted a comprehensive field study of soil bacteria, fungi, and meso- and macrofauna across natural and anthropogenic sites along the eastern coast of Peninsular Malaysia. Natural sites included primary and secondary forest, peat forest, and tropical wetland, while anthropogenic sites included paddy field, oil palm plantation, durian orchard, and urban park with different anthropogenic pressure. Alpha diversity of soil biota differed significantly across various sampling sites, but no significant pattern was found between natural and anthropogenic land uses. Primary forests showed the highest Shannon-Wiener index for bacteria (11.1 ± 0.1), fungi (7.3 ± 0.3), and fauna (2.0 ± 0.2), while other sites showed a lower Shannon-Wiener index. Soil texture influenced bacterial and fungal diversity, while soil fauna was also shaped by pH and salinity. Beta diversity of soil microbiota was influenced mainly by soil texture and pH, while beta diversity of soil fauna was driven primarily by soil texture. Anthropogenic sites exhibited higher beta diversity than natural sites. Natural and anthropogenic networks differed in connectivity, with natural systems exhibiting more balanced and modular associations, while anthropogenic sites displayed denser but less cohesive linkages. Volatile organic compound (VOCs) and greenhouse gas (GHG) fluxes also varied significantly across different sampling locations and land uses. The GHG fluxes were shaped by soil texture and soil chemistry. Bacterial and fungal VOCs positively correlated with beta diversity of bacterial and fungal communities. Overall, land use and soil texture were key drivers of the diversity and composition of soil biota and ecosystem functions.