Reductions in microbial biomass along disturbance gradients in a semi-natural grassland

► Disturbance in sandy grassland may lead to increased pH and plant available N. ► Signature fatty acids of AM fungi, saprotrophic fungi and bacteria showed that these were reduced with increasing disturbance. ► The bacterial community composition was regulated by the disturbance, and in particular the lowest level of disturbance had a specific community composition. ► We conclude that soil disturbance disfavours AM fungi due to mechanical interruption of hyphae and through reduced plant biomass.