Response of plant communities and soil characteristics to topography in three meadow habitats in a basin unit of the Yellow River source zone

This study aims to determine how plant communities and soil characteristics respond to topography in three habitats in the basin unit of the Yellow River source zone. Based on the data of field plant community species and soil factors investigated in a typical alpine meadow, we established the relationship between plant community, soil characteristics and typical topographic habitats via correlation analysis, redundancy analysis (RDA), and structural equation modelling. The results showed that: (1) Shannon‐Wiener diversity index and Pielou evenness index of the alpine meadow plant community are the highest in marshland habitat, which significantly increased by 44.97% and 48.34% over those of sunny habitat ( P < 0.05); (2) Soil water content (SWC) and organic carbon (SOC) content in different habitats were the highest in marshland habitat, which were 87.05% and 155.31 g/kg, respectively, significantly higher than in sunny habitat ( P < 0.05); (3) A large number of significant correlations ( P < 0.05) exist between community characteristics and their stoichiometric ratios, soil physical and chemical properties and soil enzyme activity. RDA analysis revealed that the hydrogen (H) content of aboveground parts of plants, carbon‐nitrogen ratio (C/N) of underground parts of plants, nitrogen‐phosphorus ratio (N/P) of soil, the nitrate nitrogen (NH 4 + ‐N) content of soil and N‐acetyl‐glucosaminidase (NAG) enzyme activity exhibit the greatest influences on community characteristics, with a contribution rate of 70.0%, 51.4%, 79.4%, 72.2% and 91.3%, respectively, all reaching the significant level ( P < 0.05). Soil nutrients affect plant diversity and productivity by affecting the nutrients and stoichiometry of aboveground and underground plants. This study shows that the change in topographic position can lead to differences in plant community characteristics and soil physical and chemical properties and has an important impact on the changes in extracellular enzyme activity and the eco‐stoichiometric ratio.