长期氮添加对典型草原植物多样性与初级生产力的影响及途径
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Effects and pathways of long-term nitrogen addition on plant diversity and primary productivity in a typical steppe
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图6. 氮添加对典型草原净初级生产力(ANPP)影响途径的结构方程模型(SEM)分析结果。c2 = 3.611, p = 0.89, df = 8, n = 13, RMSEA < 0.001, AIC = 29.61, CFI = 1.000。实线和虚线分别表示变量之间作用关系显著(p < 0.05)和不显著(p > 0.05)。正负数值表示标准化回归系数(β); *, p < 0.05; **, p < 0.01; ***, p < 0.001; r2值表示某一变量被其他变量的方差解释量。 |
Fig. 6. Structural equation model (SEM) analyses of pathways of N addition on aboveground net primary productivity (ANPP). Results of SEM fitting: c2 = 3.611, p = 0.89, df = 8, n = 13, RMSEA < 0.001, AIC = 29.61, CFI = 1.000. ANPP, aboveground net primary productivity; CWM, community-weighted mean traits; FAD, functional attribute diversity; PR/PB, biomass ratio of perennial rhizome grass to perennial bunchgrass, indicating a shift in functional group composition. Solid and dashed arrows indicate significant (p < 0.05) and non-significant (p > 0.05) effects, respectively. Values associated with solid arrows represent standardized path coefficients (β); *, p < 0.05; **, p < 0.01; ***, p < 0.001. r2 values associated with response variables indicate the proportion of variation explained by relationships with other variables. |
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