Figure 1.
Hierarchical nested sampling design used for data collection.
The hierarchical sampling system included 4 levels (corresponding to spatial scales): 270 sampling units at the plot scale were nested within 54 sampling units at the slope position scale; 54 sampling units at the slope position scale were nested within 18 sampling units of slope scale, and 18 sampling units at the slope scale were nested within 9 sampling units at the watershed scale. For the 9 watersheds, 3 watersheds were planted in pine forest, 3 in larch forest, and 3 were natural secondary broad-leaved forest.
Figure 2.
Hierarchical levels in the additive partitioning of diversity used in the study: the diversity of each scale was linked additively to form the diversity of the next higher scale (adapted from Wagner et al., 2000; Gering et al., 2003; Chávez and Macdonald, 2012).
Table 1.
Model information of the mixed-effects models used for different diversity components.
Figure 3.
Components of woody species diversity (mean alpha diversity at the plot scale, beta diversity at the plot, slope position, and slope exposure scales, and gamma diversity at the watershed scale) in the tree, shrub, and regeneration layers for different forest types.
PF-planted pine forest; LF-planted larch forest; BF-natural secondary broadleaf forest.
Table 2.
Best-fit linear mixed-effect models testing the effects of forest type, slope, slope position, and first-order interactions on alpha diversity and gamma diversity components.
Figure 4.
Box plots of alpha diversity (alpha1, alpha2, and alpha3) and gamma diversity components measured by species richness of the tree, shrub, and regeneration layers in different forest types.
The center lines represent medians, and the outer lines represent the inter-quartile range. Whisker lines represent the whole range of data that lie within one and a half times the inter-quartile range (1.5×IQR). PF, LF, BF: see Fig. 3.
Table 3.
Best-fit linear mixed-effect models testing the effects of forest type, slope, slope position, and first-order interactions on beta diversity components.
Figure 5.
Box plots of alpha diversity (alpha1, alpha2, and alpha3) and gamma diversity components measured by Simpson's diversity of the tree, shrub, and regeneration layers in different forest types.
The center lines represent medians, and the outer lines represent the inter-quartile range. Whisker lines represent the whole range of data that lie within one-and-a-half times the inter-quartile range (1.5×IQR). PF, LF, BF: see Fig. 3.
Figure 6.
Box plots of beta diversity components (beta1, beta2, and beta3) measured by species richness of the tree, shrub, and regeneration layers in different forest types.
The center lines represent medians, and the outer lines represent the inter-quartile range. Whisker lines represent the whole range of data that lie within one and a half times the inter-quartile range (1.5×IQR). PF, LF, BF: see Fig. 3.
Figure 7.
Box plots of beta diversity components (beta1, beta2, and beta3) measured by Simpson's diversity of the tree, shrub, and regeneration layers in different forest types.
The center lines represent medians, and the outer lines represent the inter-quartile range. Whisker lines represent the whole range of data that lie within one-and-a-half times the inter-quartile range (1.5×IQR). PF, LF, BF: see Fig. 3.