Figure 1
From: Species richness both impedes and promotes alien plant invasions in the Brazilian Cerrado
Structural equation model (SEM) showing direct (blue arrow) and indirect (orange arrow) connections between plant species richness and the abundance of alien plants in the Cerrado. The possible connection between species richness and soil phosphatase activity (PME) follows results obtained in the Jena Biodiversity Experiment29. Also connections between the total soil P and soil extractable P (Mehlich) pools on soil phosphatase activity, as well as a direct connection between soil extractable P and abundance of alien plants are included in the SEM. Plant variables are recorded on 334-m2 plots using the Braun–Blanquet scale, soil parameters are from the top 10-cm soil. Numbers associated with paths between variables are path coefficients presented as standardized values (scaled by the standard deviations of the variables). Solid arrows show significant connections (*p < 0.05, ***p < 0.001), dashed arrows show insignificant connections (p > 0.05). Goodness of fit of the SEM: p χ2 = 0.452 (a good model fit indicating that the fit is clearly not significantly different from the theoretical model).
