天山北坡3种草地类型植物群落特征及土壤养分化学计量特征OA

This study aimed to investigate the differences in plant community characteristics and soil nutrient stoichiometry among three grassland types:temperate desert,temperate steppe,and mountain meadow on the northern slope of the Tianshan Mountains in Xinjiang,China,as well as the relationships between them.Field sampling and laboratory analysis were conducted to determine plant community traits,soil carbon(C),nitrogen(N),and phosphorus(P)contents,microbial biomass carbon,nitrogen,and phosphorus(M BC,M BN,M BP)contents,and soil enzyme activities.Redundancy analysis(RDA)was used to identify the key environmental factors driving plant community composition.The results showed that:From temperate desert to mountain meadow,plant community height decreased significantly(P<0.05),while the coverage,density,and diversity indices(except for evenness)increased.The highest contents of soil organic carbon,total nitrogen,total phosphorus,MBC,MBN,and MBP were found in mountain meadow,whereas the soil N∶P ratio was lowest in temperate desert.The activities of β-glucosi-dase and alkaline phosphatase were highest in mountain meadow,while the activities leucine aminopepti-dase and N-acetyl-β-D-glucosaminidase were highest in temperate steppe.From temperate desert to moun-tain meadow,soil nutrients accumulated,and vegetation trended to be shorter and denser.Among three types,temperate desert grasslands were nitrogen-limited.RDA indicated that MBC∶MBN ratio and MBP were key factors driving plant community characteristics(cumulative explanation rate:66.7%).In conclu-sion,this study provides a theoretical basis for understanding of nutrient cycling and guiding the restoration of degraded grasslands in arid ecosystems.