退化高寒草甸植物功能群与土壤因子关系的冗余分析

Redundancy Analysis of the Relationship Between Plant Functional Groups and Soil Factors in the Degraded Alpine Meadow

在退化高寒草甸设置研究样地,观测植物群落特征,采集土样并分析理化性质,利用植物功能群与土壤因子数据矩阵进行冗余分析,探讨退化高寒草甸植物功能群与土壤因子间的关系。结果表明:随退化程度加剧,植物功能群中莎草科、禾本科重要值减小,杂类草重要值增大,植物功能群由莎草科、禾本科向豆科、杂类草演替;随退化程度加剧,土壤有机碳、氮含量等下降,土壤温度、容重等增大;冗余分析第1、第2排序轴解释了97.1%的植物功能群变化和99.6%的植物功能群与土壤因子关系;土壤含水量、全氮含量等与第1排序轴正相关,土壤容重、土壤温度等与第1排序轴负相关,不同土壤因子的边际作用不同,土壤含水量、全氮含量等对植物功能群分布的影响极显著(P<0.01);莎草科重要值与土壤全氮含量、含水量等的相关系数为0.960、0.959(P<0.01),禾本科重要值与土壤含水量、有机碳含量等的相关系数为0.937、0.929(P<0.01);豆科、杂类草受土壤容重、含水量等影响更大。退化高寒草甸植物功能群与土壤因子间存在相关关系,不同土壤因子对植物功能群的影响不同,植物功能群对土壤全氮含量、土壤含水量等因子的变化更敏感。

To explore the relationship between soil factors and plant functional groups(PFGs),research sample plots were set up under the degraded alpine meadow.Plant community characteristics and soil physic-chemical properties as well as their redundancy analysis(RDA)were determined.The results showed that with the aggravation of degradation,the important values of cyperaceae and gramineae PFGs tended to decrease,while forbs PFGs increase;PFGs succession was from cyperaceae and gramineae to leguminosae and forbs;Further,soil organic carbon and nitrogen tended to decrease,while soil temperature and bulk density tended to increase.From RDA,the first and second axises explained the 97.1%of PFGs variation and the relationship of 99.6%between PFGs and soil factors.Soil water content and total nitrogen showed positive correlation with the first axis,while soil bulk density and soil temperature showed negative correlation with the first axis,which indicate that various soil factors have different marginal effects.Soil water and total nitrogen contents had significant effects on the distribution of PFGs(P<0.01).The correlation coefficients between cyperaceae important value and soil total nitrogen as well as soil water content were 0.960 and 0.959,respectively(P<0.01).The correlation coefficients between gramineae important value and soil water content as well as organic carbon were 0.937 and 0.929,respectively(P<0.01).Soil bulk density and water content had important effects in leguminosae and forbs PFGs.In conclusion,there existed correlation between PFGs and soil factors in degraded alpine meadows,and various soil factors showed different effects on PFGs,which were more sensitive to the changes of soil total nitrogen and soil water content.