Soil seed banks mediate soil–vegetation coupling in mining-induced fissure landscapes

Abstract

Mining-induced ground fissures in coal-mining subsidence landscapes disrupt soil structure and near-surface hydrology, creating fine-scale habitat heterogeneity that can impede natural vegetation recovery. Soil seed banks represent a critical propagule reservoir, yet their spatial dynamics, governing drivers, and coupling with aboveground vegetation remain insufficiently quantified in fissure-affected systems. Soil seed banks were assessed at four distance classes (0–1 m, 1–2 m, 2–5 m, and a non-subsided control) and two soil layers (0–10 cm and 10–20 cm) using germination assays, together with vegetation surveys and soil physicochemical measurements. Mantel tests and structural equation modeling (SEM) were applied to identify dominant drivers and pathways. Soil seed bank density and diversity declined sharply within 0–2 m of fissures, with the strongest reductions in the surface layer, indicating a spatially bounded disturbance footprint. Soil moisture and soil organic matter exerted positive influences on soil seed bank size and composition, whereas crust thickness imposed consistent negative effects, supporting a barrier-mediated constraint on seed retention and emergence. SEM further showed that soil conditions affected vegetation density and richness largely through indirect pathways mediated by soil seed bank traits, highlighting the soil seed bank as a key intermediary linking soil degradation to vegetation outcomes. Species similarity between the soil seed bank and aboveground vegetation increased with distance from fissures; 68 species were shared overall and 16 taxa formed a core pool shared across all zones. These findings provide a mechanistic basis for distance-based, differentiated restoration in mining subsidence areas, prioritizing microsite amelioration and propagule supplementation near fissures and assisted natural regeneration in less impacted zones.