退化高寒草甸不同斑块的植被和土壤微生物特性研究OA

Alpine meadow is the predominant grassland type on the Qinghai-Xizang Plateau,and grass-land patchiness is a key indicator of moderate to severe degradation.To elucidate the restoration process and its driving mechanisms,this study was conducted in a typical alpine meadow region of the Qinghai-Xizang Plateau.Vegetation characteristics and soil microbial community structure across three slope gradi-ents(flat,gentle,and steep)and three patch types(active patches,inactive patches,and restored patches)were compared.The results showed that the vegetation cover,aboveground biomass,and Shannon index of restored patches were significantly higher than those of inactive patches(P<0.05).The plant community exhibited a clear successional trajectory,from bare ground in active patches,to dominance by annual and biennial plants in inactive patches,and finally to a community dominated by perennial Asteraceae and Cyperaceae species in restored patches(on steep slopes,by plants such as Lancea tibetica and associated forbs).In the soil bacterial community,Solirubrobacter was the most abundant dominant taxon;the rela-tive abundances of Solirubrobacter,Pseudonocardia,and Nocardioides did not differ significantly among the three patch types at any slope position,whereas the BIrii41 was significantly more abundant in inactive than in active patches on gentle and steep slopes(P<0.05),with no significant difference on flat ground.In the fungal community,Kernia was dominant in active patches,and its relative abundance decreased sig-nificantly with restoration on flat ground(P<0.05);the relative abundance of Alternaria increased mark-edly in restored patches,being approximately 77.48%higher on flat ground than in active patches.PCoA showed that bacterial communities differentiated mainly along the patch restoration stage,whereas fungal communities diverged clearly between flat ground and sloped terrain;numerically,the abundance of Pseudonocardia was slightly higher in steep-slope than in flat-ground patches.Correlation analysis showed that the plant Pielou index was significantly positively correlated with Solirubrobacter abundance,and plant cover,aboveground biomass,and the Simpson index were significantly positively correlated with Alternaria abundance(P<0.05);in contrast,plant cover,aboveground biomass,and the Shannon,Simpson diversity index,and Pielou indices were all significantly negatively correlated with Kernia abundance(P<0.05).Therefore,the patch restoration process in degraded alpine meadows is accompanied by synergistic improvements in vegetation and soil microbial communities,and restoration measures should be imple-mented precisely based on the restoration stage and topographical factors.