Vegetation and Soil Recovery in Restored Grasslands Relative to Reference Ecosystems: A Meta‐Analysis

ABSTRACT Grassland restoration is widely implemented to reverse degradation and sustain ecosystem services, yet reported outcomes vary considerably. A meta‐analysis of 25 studies (63 effect sizes) compared restored and reference grasslands, with responses quantified using log response ratios under a random‐effects framework. Subgroup and temporal analyses evaluated variation by restoration method, ecosystem type, and years since intervention. The pooled effect size was near zero (lnRR = −0.03, 95% CI: −0.19 to 0.13), with wide prediction intervals (−0.82 to 0.76) indicating substantial context dependence. Restoration consistently enhanced aboveground biomass through vegetation regrowth and canopy development, increased soil organic carbon via litter accumulation and root turnover, and reduced bulk density through aggregate formation. In contrast, total nitrogen and soil pH showed negligible effects, highlighting the slower recovery of microbial processes, nutrient cycling, and chemical equilibria. Temporal analysis revealed strong age dependence: during the first decade, ecosystem functioning lagged behind references due to low vegetation cover and soil disturbance; between 10 and 20 years, biomass accumulation improved soil structure and carbon storage; after > 20 years, restored sites partially converged with reference conditions, though full equivalence remained rare. Subgroup analyses showed reseeding accelerated vegetation establishment (25%), while grasslands recovered more rapidly (18%) than forests and wetlands, which required longer periods for canopy closure or hydrological stabilization. Findings demonstrate that vegetation and carbon pools recover first, whereas nutrient cycles and soil chemistry lag. Long‐term, ecosystem‐specific monitoring is essential for guiding sustainable restoration strategies.