Synergistic adaptation strategies involving aboveground vegetation and the soil seed bank in the Gurbantunggut Desert

Abstract

The sustainability of desert ecology depends on synergistic changes in the aboveground and soil seed banks. To explain this process, we undertook fieldwork in the largest fixed-semifixed desert in China, the Gurbantunggut Desert. Sample quadrats were examined on three types of dunes (fixed, semifixed, and mobile) for a total of 270. We studied their adaptive collaborative patterns using TWINSPAN classification, diversity analysis, and structural equation modeling. The findings revealed that the communities of plants associated with aboveground vegetation and the soil seed bank each consisted of 13 community types. The aboveground vegetation was dominated by shrubs such as Haloxylon ammodendron and Haloxylon persicum, whereas the soil seed bank was primarily composed of herbaceous species such as Alhagi sparsifolia and Salsola nitraria. The diversity of the shrub communities in the aboveground vegetation significantly exceeded that in the herbaceous communities, whereas no significant differences in the diversity of the soil seed bank were detected among the communities. The storage effect and bet-hedging strategies of these components formed spatiotemporal complementarity, thereby enhancing the ecosystem’s resilience to disturbance. The similarity between the aboveground vegetation and the soil seed bank was greatest in the shrub communities (e.g., H. ammodendron) and lowest in the herbaceous communities (e.g., S. nitraria). Soil organic carbon (SOC) and pH were identified as core drivers, with pH directly influencing seed bank diversity and SOC directly regulating aboveground vegetation diversity. Furthermore, the soil seed bank exerted a significant direct effect on the aboveground vegetation. This study demonstrated that the stability of desert ecosystems arises from functional complementarity and strategic coordination between aboveground and belowground regenerative niches, providing critical theoretical support for desertification control and vegetation restoration in arid regions.