Natural forest conversion profoundly alters soil respiration, yet its differential effects on autotrophic and heterotrophic components and their temperature sensitivity (Q10) remain unresolved globally. Here we synthesize 452 paired observations from 164 field studies, showing that soil respiration declines by 7.0% following forest conversion, primarily driven by a pronounced reduction in autotrophic respiration (−26.8%), whereas heterotrophic respiration exhibits no consistent response. Although Q10 does not shift significantly across all conversions, it increases markedly following conversion to agriculture (+8.8%) and grassland (+11.8%). Both soil respiration suppression and Q10 elevation are transient, converging toward adjacent forest levels within approximately 30 years. Variations in soil respiration reflect the opposing influences of soil organic carbon loss and post-conversion soil warming, whereas Q10 responses are strongly modulated by initial soil clay content and pH. Our findings underscore the need to incorporate component-resolved and context-dependent soil respiration and Q10 into Earth system models to improve projections of long-term carbon–climate feedbacks under land-use change. Natural forest conversion reduces soil respiration by 7% through strong declines in autotrophic respiration and raises temperature sensitivity after conversion to agriculture and grassland, with both responses returning to forest levels within 30 years, based on 452 paired observations.
Fan et al. (Wed,) studied this question.