贺兰山东坡典型植物群落多样性垂直分布特征与土壤因子的关系

深入探究山地生态系统植物群落多样性与关键土壤因子的关系及土壤因子在植物群落构建与多样性维持中的重要作用是区域生物多样性保护和生态系统服务功能综合提升的基础。本文采用冗余分析（Redundancy analysis，RDA）和相关分析揭示了贺兰山东坡典型植物群落多样性垂直分布格局与土壤因子的关系。结果表明：（1）贺兰山东坡植物群落多样性具有明显的垂直分布格局，针阔叶混交林植物物种组成最为丰富，中域效应明显；不同层次植物多样性随海拔升高变化趋势不一致且各自在不同海拔间差异显著（P<0.05），植物多样性大体表现为草本层 > 灌木层 > 乔木层。（2）研究区土壤因子沿海拔梯度变化趋势不同，均存在显著差异（P<0.05），其中土壤含水量（SM）、有机碳（SOC）和全氮（TN）含量空间变异性较大；高山灌丛草甸土壤养分含量最高，高海拔区土壤P限制高。（3）9个土壤因子解释了研究区总体植物多样性89.68%的生态信息，与植物多样性具有较强的相关性，影响不同层次植物多样性垂直分异的关键土壤因子略有不同。综上，土壤有机碳、pH、碳磷比、含水量是影响贺兰山东坡植物多样性空间分布的主要驱动因子。

Relationship between altitudinal distribution characteristics of typical plant community diversity and soil factors on the eastern slope of the Helan Mountains

To deeply explore the relationship between altitudinal distribution characteristics of typical plant community diversity and the key soil factors in mountain ecosystems, and to disclose the important role of soil factors in plant community construction and diversity maintenance are the basis of regional biodiversity protection and the comprehensive improvement of the ecosystem service function. In the present study, redundancy analysis (RDA) and correlation analysis were applied to reveal the relationship between the vertical distribution pattern of typical plant community diversity and soil factors on the eastern slope of the Helan Mountains. It was found that the plant community diversity had an obviously vertical distribution pattern. The plant species of mixed broadleaf-conifer forest were the most abundant, with an obvious mid-domain effect. The plant diversity at different layers showed different trends with the increase of altitude and each of them showed significant differences between different altitudes (P<0.05), and the general expression was herb layer > shrub layer > arbor layer. Changes in soil factors along the altitudinal gradient were different, each of which showed significant difference (P<0.05). Among them, soil moisture content (SM), soil organic carbon (SOC), and soil total nitrogen (TN) had the largely spatial variability. The soil nutrient content of alpine shrub meadow was the highest, and there was high soil P limit in high altitude areas. Nine soil factors were strongly correlated with the plant community diversity and explained 89.68% of its ecological information. The key soil factors that impact the vertical distribution of plant diversity for different plant layers were different. In conclusion, the SOC, pH, C/P ratio, and SM were the dominant factors affecting the spatial distribution of plant community diversity on the eastern slope of the Helan Mountains.