In karst fragile habitats, abiotic factors, particularly soil organic carbon, dominate over microbial communities in determining soil multifunctionality.
Description
Karst ecosystem is a typical vulnerable habitat globally, facing severe soil degradation and rocky desertification.. Revealing how different restoration approaches and disturbance intensities affect soil properties and microbial community characteristics, and clarifying the resulting differences in soil multifunctionality, is of great significance for ecological management in this region. To this end, in areas of severe rocky desertification in Southwest China, we investigated five typical land-use types to represent varying disturbance intensities and restoration approaches, mainly including: farmland (high-intensity disturbance), grassland (moderate disturbance/grassland restoration), shrubland (low disturbance/shrub restoration), plantation forest (artificially assisted restoration), and secondary forest (natural restoration). Soil samples were collected from three depths (0–10, 10–20, 20–30 cm) to assess five key soil functions: nutrient provisioning, microbial growth efficiency, soil organic matter decomposition, nutrient cycling, and plant-microbe symbiosis. We found that microbial growth efficiency, SOM decomposition capacity, and soil multifunctionality in farmland and grassland were significantly lower than those in forests. Surface soil (0–10 cm) in shrubland exhibited the highest soil multifunctionality, with significant functional variation across soil depths. In addition, farmland and grassland had higher bacterial α-diversity, and both showed significant differences from forests in the structure of bacterial and fungal communities. Shrubland exhibited higher bacterial community stability and network complexity, while plantation forests had the highest network complexity. Driving factor analysis revealed that while microbial network properties influenced multifunctionality, abiotic factors had a stronger independent explanatory power.. Structural equation modeling further identified that SOC as the key variable linking different restoration/disturbance approaches and soil layer depths, as well as enhancing soil multifunctionality. This study emphasizes the importance of adopting shrubland restoration to improve soil multifunctionality in rocky desertification areas, which not only helps to enhance the specificity and effectiveness of rocky desertification management, but also promotes the transformation of regional ecosystems from “degradation remediation” to “functional enhancement.”
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The study was supported by the National Natural Science Foundation of China (42467043), the Guizhou Provincial High-Level Innovative Talents Project (QKHPTRC-GCC[2023]015), the Basic Research Project of Guizhou University (GDJ [2024]23), and the Guizhou Provincial Young Elite Scientist Sponsorship Program.