The trade-offs among fungal guilds are associated with soil organic carbon dynamics in alpine ecosystems

Alpine ecosystems have vast amount of soil organic carbon (SOC) and are highly sensitive to climate change. Soil fungi play a crucial role in SOC cycling as decomposers but their contribution to alpine SOC dynamics across high elevation gradients remain poorly understood. Here, we explored fungal communities and their relationships with SOC content across an elevational gradient from 3,994 to 5,120 m on the Tibetan Plateau. We found that SOC content decreased by 28.3% from low to high elevation caused by the trade-offs between ectomycorrhizal fungi and non-ligninolytic saprotrophs. Higher elevation soils, with colder, wetter conditions and lower fertility, were dominated by ectomycorrhizal fungi at the expense of non-ligninolytic saprotrophic fungal species through environmental filtering and nutrient competition. Furthermore, ectomycorrhizal fungi are positively correlated with peroxidative enzyme activities, suggesting enhanced SOC turnover. Our work provides new evidence of, and insights into, the potential role of specific fungal guild trade-offs in shaping SOC fate in fragile alpine ecosystems.