Niche evolution
The results of phylogenetic signal test based on Blomberg’s K show values in PC1 and PC2 are less than 1, best-fitted to WN model, which suggests that PC1 and PC2 dimension climate changes independence of phylogenetic relationships (data with no covariance structure among clades); but more than 1 in PC3, PC4 and PC5 indicate PC3, PC4 and PC5 dimension changes have closely related phylogenetic relationships (Table 4). The comparisons of model fit based on the AICc value and AICc weights (ω) indicate that the WN model is preferred in PC1 and PC2, where climatic components change in PC1 and PC2 regardless of shared ancestry between clades. Although niche conservatism is maintained in some clades for PC1 and PC2 (Figure 2c and Table 4), our tests of PC3, PC4 and PC5 fitted to a BM model, suggesting that following a divergence event along these climate PCs, clades branches may be subject to these variable environmental conditions, such as promoting the evolution of different climatic tolerances, which may be accumulated independently from ancestral ones.