Supplementary Information
Table S4: Mean site characteristics.
Site Biome Separation MAT MAP time (y)
(°C)
(mm) pH SOC (% Texture dry wt soil)
(Sand/
(Silt+Clay))
11.34 3.13 AND Temperate 150 8.5 2257 5.15
BNZ Boreal 30
CDR Temperate 4
CWT Temperate 100
HBR Temperate 36
-2.94
6.7
13.3
5.6
269
269
1000
1400
5.42
5.32
5.08
4.84
HFR Temperate 54
KBS Temperate 120
7.1
8.8
1066
890
5.52
5.90
KNZ Temperate Natural 12.9 847 6.88
7.67
1.39
5.1
12.7
11.57 8.30
3.16 0.95
6.75 0.70
0.41
3.86
2.08
6.30
LUQ Tropical 80
NWT Boreal Natural
22.8
-3.2
1100
1000
5.93
4.79
HAW Tropical 150 15 1618 4.79
5.34
11.18
12.71
0.34
1.19
5.41
Environmental/abiotic characteristics (including MAT (mean annual temperature),
MAP (mean annual precipitation) and SOC (soil organic carbon concentration)) of each site. Sites included10 Long Term Ecological Research stations (Andrews
Experimental Forest, Oregon (AND), Bonanza Creek, Alaska (BNZ), Cedar Creek,
Minnesota (CDR), Coweeta, North Carolina (CWT), Hubbard Brook, New
Hampshire, (HBR), Harvard Forest, Massachusetts (HFR), Kellogg Biological
Station, Michigan, (KBS), Konza Prairie Biological Station, Kansas (KNZ), Luquillo,

Puerto Rico (LUQ), Niwot Ridge, Colorado (NWT)) and the Hawaii Experimental
Tropical Forest, Hawaii (HAW). Each consisted of a natural forest and a grassland maintained by minimal management.
Table S2: Effect of sample time and location on microbial community attributes.
Bacterial biomass
Fungal biomass
Test
Cover
Site
GLM
Time 0.96
Cover*Site 7.86 ***
GLM
39.74 *** 11.78 ***
16.85 *** 37.43 ***
1.18
7.47 ***
Bacterial richness
GLM
56.14 ***
9.06 ***
3.49
4.49 *
Fungal richness
GLM
29.27 ***
5.69 ***
1.48
0.85
Bacterial community composition
PERMANOVA
5.37 ***
8.01 ***
0.94
4.19 **
Fungal community composition
PERMANOVA
4.13 **
13.36 ***
1.93
4.83 **
F-values for GLMs (biomass and Shannon diversity) and pseudo-F values for
PERMANOVAs (for community composition). Stars indicate significant (* P < 0.05,
** P < 0.01, *** P < 0.001) overall effects, showing that community attributes do not change over time, but they vary between sites and cover types (first order effects) and the effect of cover type varies between sites (Cover*Site interaction)

Table S3: Factors affecting microbial susceptibility to deforestation.
Bacterial biomass
Fungal biomass
MAT
MAP
0.01
4.48
0.10
4.51 pH 1.27 0.42
Sand:(Silt+Clay) 26.24 *** 21.38 ***
% C
C:N
Time since conversion
0.47
2.90
0.90
0.01
0.74
0.24
Bacterial richness
0.51
0.08
0.18
8.41 *
<0.01
0.08
0.15
Fungal richness
0.94
3.34
0.05
4.93 *
1.83
1.85
0.24
Bacterial community Fungal community composition composition
1.13
2.14
0.18
8.10 *
<0.01
1.16
0.01
52.98 ***
1.53
1.48
11.31 **
6.95
1.97
5.98
F-values for GLMMs comparing effects of abiotic conditions (Mean Annual
Temperature, % Moisture, pH), soil texture (best representative variable: sand:(clay+silt)) and organic matter concentrations (best representative variable: % C) and macronutrient stoichiometry (C:N) on the dissimilarity between microbial community attributes in forest and grassland soil. Stars indicate significant (* P <
0.05, ** P < 0.01, *** P < 0.001) overall effects.

Table S4: Effect of sample time and location on the carbon mineralization indices.
Test
Cover
Site
Time
Cover*Site
CRP dissimilarity
PERMANOVA
1.89
2.87 ***
3.41 **
2.32 **
Respiration
GLM
4.49 *
0.21
0.89
0.61
F-values for GLMs (respiration) and pseudo-F values for PERMANOVAs (CRP dissimilarity). Stars indicate significant (* P < 0.05, ** P < 0.01, *** P < 0.001) overall effects. The catabolic response profile (CRP) of each soil was calculated by estimating the relative mineralization of eight common organic compounds, each expressed per unit microbial biomass. Respiration was estimated using the mineralization rates of carbon from non-amended soil.
Figure S1:
Map displaying the locations and the forest characteristics of each site.
Figure S2:
Bacterial (A) and fungal (B) community composition in 66 soil samples collected from 22 sites across 3 years. Figures show PCoA plots of microbial OTU composition based on the Bray-Curtis metric of dissimilarity. These plots capture 29.9% and 7.8% of the dissimilarity in bacterial and fungal community dissimilarity, respectively.
Cover type is indicated by shape (forest and herb are circles and triangles, respectively) and site is indicated by color. ‘Cover type’ and ‘site’ significantly
(PERMANOVA; P
≤
0.05) affected fungal and bacterial community composition at

the continent-scale.