Feedbacks between vegetation and soil in global Forest degradation: a meta-analysis

Forest degradation represents a major global environmental challenge, yet its impacts on both aboveground vegetation and belowground soil properties remain insufficiently understood. Using a meta-analysis of 440 cases from 148 studies, this study systematically evaluated the effects of forest degradation on forest structure, plant diversity, and soil properties, and elucidated the synergistic response mechanisms between aboveground and belowground components. Our results indicate that forest degradation markedly decreased aboveground biomass (−132%), basal area (−91%), stand density (−58%), plant diversity (−36%, −14%, and − 40% for Shannon-Wiener diversity index, Pilou evenness index, and species richness), reduced soil organic carbon (−34%), total nitrogen (−34%), microbial biomass carbon (−47%) and microbial biomass nitrogen (−60%). Significant negative effects were observed in all disturbance types, with agricultural expansion associated with the most pronounced impacts. Aboveground vegetation declines were significantly and positively correlated with the decrease in soil carbon and nitrogen indicators, suggesting synergistic degradation dynamics between aboveground and belowground processes. This study reveals through global meta-analysis that effective management of forest degradation must integrate aboveground vegetation reconstruction with belowground soil restoration and employ systematic interventions to mitigate degradation effects, thereby providing empirical support for ecological management of degraded forests worldwide. • Forest degradation significantly alters forest structure, plant diversity, and soil health. • Agricultural expansion causes the greatest structural damage among disturbance types. • Aboveground biomass loss is tightly coupled with declines in soil carbon and nitrogen. • Integrated restoration of vegetation and soil is critical for degraded forest recovery.