Selective logging alters soil microbial communities and supresses biogeochemical cycling in Bornean tropical forest
Rainforests provide vital ecosystem services that are underpinned by plant-soil interactions. The forests of Borneo are globally important reservoirs of biodiversity and carbon, but most of the forest that remains after large-scale agricultural conversion has been extensively degraded for timber.  We have limited understanding of how selective logging affects ecosystem biogeochemical cycles driven by soil microbes. In this study we sampled soil from logging gaps and co-located intact lowland Dipterocarp rainforest in Borneo. We characterised soil bacterial and fungal communities and physicochemical properties, and determined carbon and nutrient cycling rates. Logging significantly altered bacterial and fungal communities and soil properties, reducing the abundance of ectomycorrhizal and increasing arbuscular mycorrhizal fungi. We found lower nitrate supply rates, less inorganic phosphorous and reduced heterotrophic respiration in logged soils, suggesting overall down-regulation of microbial activity and nutrient cycling. Within gaps, logging intensity drove ectomycorrhizal abundance and phosphomonoesterase activity (negatively related) and ammonium supply rates (positively related), suggesting control on soil phosphorus and nitrogen cycling via functional shifts in fungal communities. Overall, our results demonstrate that selective logging  of tropical forest significantly impacts key soil microbial groups linked to regulation of vital carbon and nutrient cycles, with implications for landscape scale ecosystem functioning.