FIGURE 2.

Simulated data. Log‐ratio PCA and diagnostics (columns) for three levels of library size variability (rows: ${\sigma }_a$=0, ${\sigma }_a$=0.5, ${\sigma }_a$=1). The first column (a, d, g) displays the simulated observations on the 1st and 2nd principal axes, and colours indicate treatment groups. The second column (b, e, h) displays the correlation between S (clr‐transformed abundances) and $\mathrm{r}$, and the third column (c, f, i) displays the contribution of a taxon versus its log mean abundance. For ${\sigma }_a=1$, the 1st axis contains the effect of $\mathrm{r}$ and the effect of $\mathrm{x}$ is pushed to the 2nd axis