The distribution of soil fungal communities along an altitudinal gradient in an alpine meadow

Altitude can drive the distribution of living organisms through effects on both soil properties and plant-fungi interactions. We examined how altitude influenced soil fungal communities (including three ecological groups), directly and indirectly through variation in soil properties and/or plant communities, by sampling along an altitudinal gradient from 1300 to 4200 m a.s.l. in an alpine meadow in Western China. We found that soil properties (r = 0.401; P = 0.001) and plant communities (r = 0.332; P = 0.001) significantly affected soil fungal community composition. Soil nitrogen content, altitude and nitrate nitrogen content were the best predictors of saprophytic, symbiotic and biotrophic fungi, respectively. Altitude increased the relative abundance (standard coefficient = 0.385) and richness (standard coefficient = 0.689) of soil saprophytic fungi by promoting soil nitrogen content (standard coefficient = 0.574). Altitude directly increased soil symbiotic fungi (standard coefficient = 0.811), while nitrate nitrogen content promoted the richness and abundance of plant fungal pathogens. Our results shed light on drivers of soil fungi community composition and the distribution of different ecological groups along an altitudinal gradient in an alpine meadow.