Figure 3: Major clade habitat distribution maps.

Maps of the sequence relative abundance as predicted by habitat distribution models for the three most abundant clades with a strong correlation with environmental variables. Each relative abundance map is depicted with four dimensions, the length and width representing geographical space, the vertical dimension representing forb abundance for the upper two maps and soil pH for the bottom map (hash mark scale on the right) and colour representing the relative abundance of each of the clades (scale on left, red=high; blue=low). The clades are (a) Rhizobiales, (b) Rhodospirillales and (c) Acidobacteria G4. The clade with the fourth highest relative abundance, the Saprospirales, had a distribution very similar to that of the Acidobacteria G4 and is not shown. The maps were created by cokriging²⁵, an interpolation method that uses the 85 relative abundance measurements in combination with the environmental predictors from our model at all 160 sample locations to create a continuous map of relative abundance in the sampling area. The bottom topographic map shows the two-dimensional extent of the landscape.