The Microbial Network Stability in Cyanobacterial and Moss Biocrusts Respond Differently to Climate Warming.

Climate warming-a key driver of global change-significantly affects soil microbial communities and network stability. Biological soil crusts (biocrusts) help mitigate these impacts while maintaining soil ecological functions and biodiversity. However, how microbial networks and community dynamics respond to warming remains poorly understood between biocrust types, namely cyanobacterial and moss biocrust. In this study, we investigated the effect of warming on microbial communities and network stability in these biocrusts within the Mu Us Sandland, China. Using structural equation modeling (SEM), we found that warming altered microbial network properties: compared to the control, warming increased network vulnerability and decreased robustness specifically in cyanobacterial biocrusts. Warming and decreased soil moisture acted as strong filtering factors, resulting in lower microbial network stability. Although overall network complexity remained unchanged, warming reduced connectivity in cyanobacterial biocrusts, thus undermining network stability. Moreover, under both warming and control conditions, moss biocrusts exhibited lower robustness but higher vulnerability than cyanobacterial biocrusts, indicating cyanobacterial biocrusts displayed greater microbial network stability in comparison. Additionally, warming reduced the number of module hubs and keystone phyla in both biocrust types, decreasing key taxa abundance and weakening direct microbial interactions. We concluded that warming impaired microbial network stability by reducing connectivity in cyanobacterial biocrusts. These findings highlight the superior capacity of cyanobacterial biocrusts to sustain soil microbial network stability under climate warming and identify shifts in network connectivity as a central mechanism driving biocrust responses to environmental stress.