Fig. 2: Tree-driven differences in soil microbial communities and soil chemistry.

a Mean bacterial community turnover for diversity orders q = 0–2 (when turnover/β-diversity = 0 tree and interspace communities are identical; when turnover/β-diversity = 1 tree and interspace communities did not share any members). b Mean fungal community turnover for diversity orders q = 0–2. c Mean differences in soil carbon (C), soil nitrogen (N), and soil pH between each tree-interspace pair. Error bars in each panel represent 95% confidence interval of the mean. d Population-level differences in bacterial community turnover (q = 2; 1/γ (reciprocal of Simpson’s γ)) between tree-interspace pairs. e Population-level differences in fungal community turnover (q = 2) between tree-interspace pairs. P. angustifolia populations across the 15 watersheds are arranged from coolest to warmest. Center line in each boxplot represents the median turnover for each tree population, end lines represent lower and upper quartiles, and whiskers represent the minimum and maximum turnover estimates within each tree population. Blue and red boxplots match Fig. 1 and represent populations re-sampled in 2015 for soil inoculation experiment. *The soil microbiome was not sequenced for the Gros Ventre River population but was included in the inoculation experiment.