Burrowing-mammal-induced Enhanced Soil Multifunctionality is Associated with Higher Microbial Network Complexity in Alpine Meadows

The Plateau pika, a native burrowing mammal in alpine ecosystems, induces significant alterations in both the diversity and functions of the above-ground plant community; however, their effects on the below-ground soil microbial community and its multifunctionality remain unclear. Here, we examined the impact of plateau pika disturbance on soil microbial diversity, composition, and network patterns and assessed the relationships of this microbial response with soil multifunctionality, including soil carbon, nitrogen, and phosphorus cycling, based on a field investigation of alpine grassland in the Qinghai-Tibetan Plateau. Results showed that as the distance from the pika holes decreased, moisture, soil organic carbon, dissolved organic carbon, and C:N ratios significantly decreased, while available potassium and phosphorus, nitrate contents, and soil multifunctionality increased. Pika disturbance increased soil bacterial and fungal diversity (e.g., Chao estimator, richness, and Shannon index), and altered the community composition, with a higher relative abundance of Actinobacterial and a lower relative abundance of Acidobacterial in disturbed habitats than in undisturbed habitats. The bacterial and fungal network complexity (including the node and edge numbers, linkage density, and average clustering coefficient) increased as the distance from the pika holes decreased. Network complexity explained most variations of soil multifunctionality, although there were significant linear positive relationships between microbial diversity, network complexity, and soil multifunctionality. These results indicated that plateau pika activity benefits the below-ground community diversity and soil multifunctionality of alpine grassland. This highlights the importance of microbial network complexity in linking the microbial community with soil multifunctionality.