Figure 2 The figure depicts temporal effects of network structure on species diversity of communities. The trends about the effects of the short network (blue line) and the nested network (red line) on the alpha diversity (a), the gamma diversity (b), species colonization (c) and species emigration (d) are given. The independent sample T-test is used to test whether there are significant differences in the effects of the two structures on the community attributes over years. Note: *< 0.05, **< 0.01, ***<0.001.
The effects of short network and nested network on community species diversity were significantly different in various scales. In terms of the small-scale alpha diversity, although affected by abiotic factors, the effects of the two kinds of networks basically showed an increasing trend. Species richness in the nested network is always significantly higher than that in the short network (in Fig. 2a). The nested network was significantly more conducive to maintain of the alpha diversity (\(T_{\text{test}}=-5.568,\ \ P<0.001\)). For the large-scale gamma diversity, the community diversity increased significantly over time under the regulation of nested network (\(T_{\text{test}}=2.6075,\ \ P<0.005\), in Fig. 2b). Nested network is more conducive to the colonization of new species at the later stage of the experiment (in Fig. 2c). The effects of the two kinds of networks on species emigration has no significant rule, so the environmental factor such as draught and precipitation maybe play more role (in Fig. 2d).

3.2 Network structure affects species attributes