Vegetation restoration patterns and soil properties jointly affected the ecosystem multifunctionality in the karst region

Large-scale vegetation restoration has the potential to profoundly impact the ecosystem functions of the Karst region in southwest China. However, most existing studies primarily focused on individual aspects such as nutrient dynamics, water availability, biomass production, lacking comprehensive research on ecosystem multifunctionality (EMF). We collected 60 soil samples from three typical forest and grassland restoration patterns to investigate how plant restoration patterns influence EMF and soil microbial diversity. Based on correlation analysis and structural equation modeling, we explored the relationships between soil properties (e.g. soil pH, moisture, and microbial diversity in different soil layers) and EMF. The results demonstrate that, compared with the single forest and grass restoration models, the combined forest-grass model enhanced both EMF and the topsoil bacterial diversity. Across the three restoration models, microbial diversity decreased significantly with increasing soil depth, whereas fungal co-occurrence network complexity increased. Structural equation modeling identified soil bacterial co-occurrence network complexity as the key determinant of EMF in both top and subsurface soil layers. Moreover, soil pH, moisture, and microbial diversity affected EMF primarily through their effects on soil bacterial co-occurrence network complexity. Notably, subsurface soil properties explained a greater proportion of the variance in EMF (40%) than did topsoil properties (31%). These findings highlight the importance of multi-species integrated forest-grass restoration in enhancing EMF, while also emphasizing the crucial roles of bacterial co-occurrence network complexity and deeper soil layers in maintaining EMF.