FIGURE 4.

Comparison of ecological and phylogenetic similarity. (A) Phylogenetic strength (PS) estimated independently by Blomberg’s K and phylogenetic eigenvector regression. For all tested environmental variables, the strength of the phylogenetic signal was significant (Blomberg’s K always < 1; p < 0.001). By convention, the area under the phylogenetic-signal-representation curve (PSR area) is considered negative if the phylogenetic signal is smaller than expected under Brownian motion. Black line shows the regression line. (B) Maximum Likelihood tree of 4,154 full length 16S sequences. Subdivisions are colored. The color code of the outer ring indicates to which of the 13 ecological groups (Figure 2) the tips belong to, otherwise the tips are not colored. See “Results” section for further figure elements such as arrows.