Biocrusts occupy the surface of soils, house key microbes and non-vascular plants, and further provide other vital ecological functions in oligotrophic drylands. However, little is known about the impact of trampling on fragile biocrusts in temperate deserts, particularly changes to soil microbial communities. To examine this, fresh soils from three trampled intensities to biocrusts were sampled in vegetation areas of the Tennger Desert. Soil microbial biomass carbon and nitrogen, and microbial communities were studied using chloroform fumigation and Illumina sequencing, respectively. The results collected 2050 OTUs and 393 species of bacterial communities and 1124 OTUs and 135 species of fungal communities. Severe trampling of biocrusts resulted in a reduction in soil microbial biomass carbon and nitrogen, and soil microbial abundance and diversity; changed the relative abundance of microbial taxa; altered the soil microbial community structures of cyanobacteria-dominated crusts, and further affected microbial community functions. Reduced soil moisture and nutrients and enhanced pH were the factors which caused alteration in soil microbial communities after trampled biocrusts. In addition, there was a negative correlation between trampling intensity with soil nutrient content, soil microbial biomass carbon and nitrogen, and microbial abundance. After similar trampling intensity, later-succession moss-dominated crusts were significantly higher in soil nutrients, soil microbial biomass carbon and nitrogen, soil fungal abundance and diversity, and more distinctive microbial community structures compared to early-succession cyanobacteria-dominated crusts. This suggests that there is a positive correlation between biocrust tolerance to trampling and the successional stages of biocrusts. Therefore, severe trampling of biocrusts could modify biocrust fragile structures and functions, which in turn, altered soil microbial community compositions and structures, and discouraged their function, leading to a degradation process of surface soils in temperate desert ecosystems.

Dryland area accounts for approximately 40% of worldwide land area, which plays a significant role in regulating the carbon sequestration capacity of land. Vegetation restoration in drylands adopted to prevent land degradation, and may also serve as a carbon sink in the earlier stage. However, the persistence of the carbon sink for the revegetated ecosystem in drylands is still unknown. Can the well-established restoration vegetation in dryland areas serve as a carbon sink in long-run? To address this question, we investigated the carbon sequestration capacity of planted vegetation in dryland areas with 13 years of observation (2009–2021) for established vegetation restoration, which began in 1989. We found that the revegetation area serves as a carbon sink in all years. The mean annual net ecosystem productivity (NEP) is 91.61 ± 36.17 gC m−2 yr−1 (mean ± standard deviation). Annual NEP showed a significant increasing trend over the study period with a rate of 5.65 gC m−2 yr−1 yr−1 (p<0.05). The increase in spring temperature, the earlier start of net carbon uptake, and the longer duration of net carbon uptake contribute to the gradual trend of NEP. The amount of annual NEP is predominantly determined by summer precipitation. Meanwhile, our results revealed that the increase in net carbon uptake by revegetation did not lead to excessive consumption of water resources. Our results have suggested that appropriate vegetation restoration in arid areas can increase ecosystem carbon sequestration over longer timescales and mitigate climate change, with relatively low environmental consequences and risks. Considering the vast area of degraded land in the global drylands, the carbon sequestration effect of this model should be given more attention .