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黄土高原腹地人工林下草本层群落构建机制
施晶晶1,2,赵鸣飞1,2,王宇航1,2,薛峰1,2,康慕谊3,1,江源1,2,3,*()
Community assembly of herbaceous layer of the planted forests in the central Loess Plateau, China
SHI Jing-Jing1,2,ZHAO Ming-Fei1,2,WANG Yu-Hang1,2,XUE Feng1,2,KANG Mu-Yi3,1,JIANG Yuan1,2,3,*()

图2. 随机森林模型(RF)和基于距离矩阵的多元回归方法(MRM)结果。A1, A2, 分别为生态因子的重要性大小及显著性检验的结果。B, β多样性与地理距离的关系。C, β多样性与环境距离的关系。AP, 年降水量; Asp, 坡向; BA, 胸高断面积和; Den, 立木密度; DeltaH, 冠层厚度; Ele, 海拔; Geo, 地理距离; HC, 草本层盖度; MAT, 年均气温; Slo, 坡度; TC, 乔木层盖度; TH, 乔木高。虚线为Lowess拟合线, 实线为线性拟合回归线。

Fig. 2. Results of random forest (RF) model and multiple regression method (MRM) based on distance matrices. The importance of the ecological factors and the test results of significance are shown in A1 and A2, respectively; B and C respectively shows the relationship between dissimilarity of species composition with increasing geographical and environmental distance. AP, annual precipitation; Asp, aspect; BA, basal area; Den, density; DeltaH, delta height; Ele, elevation; Geo, geographical distance; HC, herbaceous coverage; MAT, mean annual temperature; Slo, slope; TC, tree coverage; TH, tree height. Dashed line represents Lowess line, solid for linear fitted regression line.