Grazing greatly reduces the temporal stability of soil cellulolytic fungal community in a steppe on the Tibetan Plateau

Excessive livestock grazing degrades grasslands ecosystem stability and sustainability by reducing soil organic matter and plant productivity. However, the effects of grazing on soil cellulolytic fungi, an important indicator of the degradation process for soil organic matter,remain less well understood. Using T-RFLP and sequencing methods, we investigated the effects of grazing on the temporal changes of cellulolytic fungal abundance and community structure in dry steppe soils during the growing months from May to September, on the Tibetan Plateau using T-RFLP and sequencing methods. The results demonstrated that the abundance of soil cellulolytic fungi under grazing treatment changed significantly from month to month, and was positively correlated with dissolved organic carbon(DOC) and soil temperature, but negatively correlated with soil p H. Contrastingly, cellulolytic fungal abundance did not change within the fencing treatment(ungrazed conditions). Cellulolytic fungal community structure changed significantly in the growing months in grazed soils,but did not change in fenced soils. Grazing played a key role in determining the community structure of soil cellulolytic fungi by explaining 8.1% of the variation, while p H and DOC explained 4.1% and 4.0%, respectively. Phylogenetically, the cellulolytic fungi were primarily affiliated with Ascomycota(69.65% in relative abundance) and Basidiomycota(30.35%).Therefore, grazing substantially reduced the stability of soil cellulolytic fungal abundance and community structure, as compared with the fencing treatment. Our finding provides a new insight into the responses of organic matter-decomposing microbes for grassland managements.

Disparity in soil bacterial community succession along a short time-scale deglaciation chronosequence on the Tibetan Plateau

Global warming leads to deglaciations in high-elevation regions,which exposes deglaciated soils to microbial colonization.Disparity in year-to-year successional patterns of bacterial community and influencing factors in freshly deglaciated soils remain unclear.We explored the abundance of bacterial 16S rRNA gene and community succession in deglaciated soils along a 14-year chronosequence after deglaciation using qPCR and Illumina sequencing on the Tibetan Plateau.The results showed that the abundance of bacterial 16S rRNA gene gradually increased with increasing deglaciation age.Soil bacterial community succession was clustered into three deglaciation stages,which were the early(zero-year old),transitional(1-7 years old)and late(8-14 years old)stages.A significantly abrupt bacterial community succession occurred from the early to the transitional stage(P<0.01),while a mild succession(P=0.078)occurred from the transitional to the late stage.The bacterial community at the early and transitional stages were dominated by Proteobacteria,while the late stage was dominated by Actinobacteria.Less abundant(<10%)Acidobacteria,Gemmatimonadetes,Verrucomicrobia,Chloroflexi,Planctomycetes,unclassified bacteria dominantly occurred in the transition and late stage and Cyanobacteria in the early stage.Total organic carbon(24.7%),post deglaciation age(21%),pH(16.5%)and moisture(10.1%)significantly contributed(P<0.05)to the variation of bacterial community succession.Our findings provided a new insight that short time-scale chronosequence is a good model to study yearly resolution of microbial community succession.

Disparity in soil bacterial community succession along a short time-scale deglaciation chronosequence on the Tibetan Plateau

Erratum to Soil Ecol.Lett.Doi:10.1007/s42832-020-0027-5 The original version of this article unfortunately contained a mistake.The author Yue Xie should be changed to Ying Xie.The online versin of the original article can be found at https://doi.org/10.1007/s42832-020-0027-5.