Grassland Agri-Husbandry Research Center, College of Grassland Science, Qingdao Agricultural University, Qingdao, 266109, China.
Sci Rep. 2021 Jun 2;11(1):11538. doi: 10.1038/s41598-021-91182-7.
Over half of the alpine meadows in the Qinghai-Tibet Plateau (QTP) are degraded due to human activities. Soil degradation from overgrazing is the most direct cause of grassland degradation. It is thus important to synthesize the effects of multiple soil degradation indicators on the belowground biomass of plants and soil microorganisms in the degraded QTP. We studied the diversities and structures of soil bacterial and fungal communities using soil bacterial 16S rRNA and the fungal ITS gene under four degradation gradients, D1: lightly degraded, D2: moderately degraded, D3: highly degraded, and a non-degraded control site (CK). The bacterial Shannon diversity in D3 was significantly lower than that in D1 (p < 0.001), and the bacterial richness index in D3 was significantly lower than that in D1 (p < 0.001). There was no difference in soil fungal diversity among the different degradation levels; however, soil fungal richness decreased significantly from CK to D3. The phyla Actinobacteria, Acidobacteria and the genus Mortierella were differed significantly under the four degradation gradients. Plant litter mass and root C/N ratio were important factors associated with bacterial and fungal diversity and richness. These results indicated that alpine meadow degradation can lead to variations in both microbial diversity and the potential functioning of micro-organisms in the QTP.
青藏高原（QTP）超过一半的高山草甸由于人类活动而退化。过度放牧导致的土壤退化是草原退化的最直接原因。因此，综合多种土壤退化指标对退化 QTP 地下生物量和土壤微生物的影响非常重要。我们研究了土壤细菌 16S rRNA 和真菌 ITS 基因在四个退化梯度（D1：轻度退化、D2：中度退化、D3：高度退化和非退化对照点（CK））下土壤细菌和真菌群落的多样性和结构。D3 中的细菌 Shannon 多样性明显低于 D1（p<0.001），D3 中的细菌丰富度指数明显低于 D1（p<0.001）。不同退化水平之间土壤真菌多样性没有差异；然而，土壤真菌丰富度从 CK 到 D3 显著下降。放线菌门、酸杆菌门和 Mortierella 属在四个退化梯度下差异显著。植物凋落物质量和根 C/N 比是与细菌和真菌多样性和丰富度相关的重要因素。这些结果表明，高山草甸退化会导致 QTP 中微生物多样性和微生物潜在功能的变化。
