Successional changes of fungal communities along the biocrust development stages

Abstract

Fungal communities play critical roles in maintaining the structure and function of biocrust in desert ecosystems. However, the successional changes of fungal communities along the biocrust development stages are not fully understood. In this study, we investigated the fungal community compositions inhabiting different biocrust successional stages (bare sand, algal crusts, lichen crusts, and moss crusts) and their relationships with environmental factors in the Gurbantunggut Desert of Northwestern China. Our results showed that fungal diversity did not change significantly along the successional stages. However, fungal biomass in lichen and moss crusts was significantly higher than those in bare sand and algal crusts. Fungal communities also showed significant successional changes with biocrust development from bare sand, algal crusts, lichen crusts, to moss crusts. At the class level, algal and lichen crusts were dominated by Dothideomycetes, Eurotiomycetes, and Lecanoromycetes, while moss crusts were dominated by unidentified Ascomycota, Eurotiomycetes, and Dothideomycetes. Successional changes also occurred at genera level. The dominant OTUs were affiliated to unknown genera in Pleosporales, Humicola, and unknown genera in Chaetomiaceae in bare sand; Endocarpon, unknown genera in Pleosporaceae, and Humicola in algal crusts; Endocarpon, Heteroplacidium, and unknown genera in Lecanorales in lichen crusts; and Heteroplacidium, Endocarpon and unknown genera in Pleosporales in moss crusts. Changes in soil organic C, conductivity, and soil bulk density were associated to the shifts in fungal community compositions, suggesting that the accumulations of soil nutrients and salts may drive the changes in biocrust fungal compositions.