Structural characteristics and spatial heterogeneity of vegetation and below-ground habitat during the long-term succession of ecosystems in mining areas

Mining activities can cause significant disturbances to ecosystems. To investigate the long-term impacts of mining and ecological restoration on vegetation communities and their below-ground habitat structure in mining areas, this study aims to reveal the relationship between aboveground and underground vegetation structures and explore the spatial heterogeneity of vegetation root systems and soil properties across different soil layers. This study uses the natural background area as a reference ecosystem and selects the mining disturbance area, mining restoration area, and natural background area in the southern Taihang Mountains as the research sites. Field surveys and laboratory analyses of plant communities and their below-ground habitats were conducted using ecological geology theories and methods. This mainly included plant species, height, and cover, as well as the distribution of fine roots and soil physicochemical properties within soil profiles (0–100 cm). Firstly, mining activities impose long-term adverse impacts on vegetation diversity and growth, resulting in a “patchy” distribution of vegetation and soil that disrupts the synergistic interactions between vegetation and soil systems. However, mine restoration gradually re-establishes the coordination between vegetation and soil systems. Secondly, there is a strong correlation between the aboveground and underground structures of vegetation. Both the aboveground and underground components of vegetation exhibit a layered structure. The distribution range of root systems varies across different plant species. Significant differences in the frequency of fine roots are observed in the soil surface layer (0–20 cm) between different ecosystems, with overlap occurring in the 20–40 cm layer, and minimal differences found in the 40–100 cm layer. Finally, the contents of soil available N, available P, and organic matter exhibit a decreasing trend with increasing soil depth, with distribution curves resembling an “S” shape. Nutrient levels are higher in the surface soil, where fine plant roots are concentrated. A layered pattern exists in the spatial heterogeneity of plant root systems and soil available N, available K, available P, and organic matter. It is suggested that the relationship between plant diversity and soil spatial heterogeneity should consider the below-ground habitat range associated with the survival of tree, shrub, and grass vegetation. This study is of significant importance for scientifically guiding the ecological environment protection and restoration of mining areas.