Abstract: To understand the distribution pattern of soil fungal communities along an elevation gradient at small scale, the high-throughput sequencing technology was used to explore the diversity and composition of soil fungal communities in different soil layers (topsoil, 0-5 cm; subsoil, 5-20 cm) at three elevations (4902, 4944, 4989 m) in an alpine meadow of Noijin Kangsang Peak, Qinghai-Tibet Plateau, and the influencing factors were examined. Results showed that there was no significant difference in fungal diversity in the topsoil and the subsoil along the small scale elevation gradient, but community composition changed significantly (P<0.05). Moreover, soil fungal community composition in the topsoil was mainly affected by soil water content (SWC), carbon-nitrogen ratio (C/N), nitrogen-phosphorus ratio (N/P), carbon-phosphorus ratio (C/P), and plant diversity. With increasing elevation, SWC, N/P, C/P, and plant diversity increased, while C/N decreased, resulting in much higher relative abundance of Ascomycota_unclassified in low elevation (4902 m) than that in middle elevation (4944 m) and high elevation (4989 m). The difference in soil fungal community composition in the subsoil layer across the altitudinal gradient was mainly affected by belowground biomass and plant diversity. Both belowground biomass and plant diversity increased with elevation, resulting in higher relative abundance of Leotiomycetes at the low elevation than that in middle and high elevations. The Ascomycota_unclassified and Hymenochaetales were the indicator taxa in the topsoil at the class level and the order level, respectively. The Microbotryomycetes_unclassified and Helotiales were the indicator taxa in the subsoil at the order level. By exploring the distribution pattern and influencing factors of soil fungal community across a small-scale elevation gradient in alpine grasslands, our results provide great significance for understanding the driving mechanism of soil fungal community change.

Key words: altitudinal gradient, soil fungi, community structure, Qinghai-Tibet Plateau