Figure 4.

The environmental factors that predict the overall similarity of leaf epiphytes. The results from PCA of (a, b) fungi and (c, d) bacteria on the leaves of (a, c) North American and (b, d) European samples. Each PCA was performed with the top 250 taxa within each community. The green dashed lines indicate the environmental variables identified using a forward selection procedure (n = 99,999 permutations; FDR q ≤ 0.10) [Colour figure can be viewed at wileyonlinelibrary.com]