Fig. 5.

Structural equation models. In (a) the exogenous variable is the phylogenetic distance (PD), whilst in (b) the exogenous variable is differences in size (∆ size). Species coexistence is present as the endogenous variable, and niche differences (ND) and relative fitness differences (RFD) are mediator variables. β indicates unstandardized regression coefficients. Arrows indicate the direction of the interactions between variables, pointing towards endogenous variables. The weight of the arrows is proportional to the regression coefficients, with dashed lines representing no significant relationships between variables. The overall goodness-of-fit test (χ², CFI, TLI) and the regression coefficient R² for each variable introduced are given. CFI, comparative fit index; LTI, Tucker-Lewis index