新疆高寒草原围封恢复过程植物、土壤与菌根真菌群落的响应特征OA

Fencing enclosure serves as a critical strategy for the restoration of degraded grassland.It promotes the restoration of ecosystem functions by regulating vegetation community characteristics and soil physical and chemical properties,thereby reshaping the structure and function of microbial communities.However,current research mostly focuses on the impact of fencing duration on vegetation and soil properties,while the dynamic response and influencing factors of the arbuscular mycorrhizal fungi(AMF)community have not been fully explored.Taking the Bayanbulak alpine grassland in Xinjiang as the study area,treatments were established:free grazing,short-term(3 years),medium-term(13 years),and long-term(40 years)fencing enclosure.By combining field surveys with Illumina MiSeq High-throughput sequencing technology in the laboratory,the changes and driving factors of the AMF community during the coordinated evolution of the soil-plant system were investigated.The results indicated that,with increasing fencing duration,aboveground plant biomass and vegetation coverage continued to rise,and the plant species richness reached its peak under medium-term fencing.The soil pH significantly decreased(free grazing vs.long-term fencing,Δ=0.30).The soil nutrients initially increased and then decreased,and their content was the highest under medium-term fencing.The AMF hyphal length density and spore density in soils under long-term fencing were 1.25 times and 3.34 times those of free grazing,respectively.Compared with free grazing,although fencing did not significantly change the AMF community alpha diversity,it significantly changed the AMF community composition.Specifically,long-term fencing significantly increased the relative abundance of the dominant genus Glomus by 117.17％compared with free grazing,while the relative abundance of Diversispora significantly decreased by 76.48％.Correlation analysis showed that the AMF community diversity was jointly affected by plant species richness and soil nutrients.Redundancy analysis further revealed that soil pH was the key factor driving the AMF community composition.Hierarchical partitioning analysis then indicated that soil chemical factors(pH,nitrate nitrogen,and ammonium nitrogen)and plant species richness acted synergistically and together explained 55.80％of AMF community composition variation.Among them,soil ammonium nitrogen and plant species richness contributed the most significantly,followed by soil pH and nitrate nitrogen.In summary,fencing enclosure regulates the AMF community composition by driving the coordinated evolution of the vegetation-soil system,and reveals the key influencing factors of the mycorrhizal symbiotic system in grassland restoration.Ultimately,this study provides a new theoretical perspective and scientific basis for understanding the restoration processes of degraded grassland ecosystems.