Variations in species and function diversity of soil fungal community along a desertification gradient in an alpine steppe

•Glomeromycota and Zygomycota can indicate desertification conditions.•Symbiotroph and Pathotroph-Saprotroph can indicate desertification conditions.•Species composition had stronger variations along the desertification gradient.•Combination of species and function composition as indicators may be better. Desertification can pose threats to global socioeconomic development, ecological and environmental safety, human health and survival. Species and function diversity are two aspects of biodiversity, and soil fungal community are important decomposers, playing important roles in element cycling. A field experiment was performed along a desertification gradient in an alpine steppe, the Northern Tibet to investigate how can the species α-diversity and composition, function α-diversity and composition change. No significant differences of species α-diversity were observed among the five desertification treatments. A significant difference of the function α-diversity was only observed between the light and severely heavy desertification treatments. Significant differences of species composition were observed between any two of the five desertification treatments. Function composition between not all any two treatments had significant differences. The changes of species and function composition along the desertification gradient were mainly attributed to BGB:AGB, 0.15–2 mm and