1
Supporting Information
2
Table S1 Selected treatments from the full IMGRE experiment. “×” indicates the removal of a plant
3
functional group (PFG). PFGs: PB, perennial bunchgrasses; PR, perennial rhizomes; PF, perennial forbs;
4
AB, annuals/biennials.
Treatment number
Number of PFGs removed
1
0
2
1
3
1
4
1
5
1
6
2
×
7
2
×
8
2
×
9
2
×
10
2
×
11
2
12
3
×
×
13
3
×
×
14
3
×
15
3
16
4
Total number of plots
5
AB
PF
PR
PB
Replicates
5
×
5
×
5
×
5
×
×
5
×
5
×
×
×
×
5
5
5
×
5
×
5
×
5
×
5
×
×
5
×
×
×
5
×
×
×
5
80
1
Table S2 Treatments for detecting the effects of plant functional group (PFG) identity on
2
above-ground plant biomass, soil properties, and the characteristics of soil microbial and nematode
3
communities. PFGs: PB, perennial bunchgrasses; PR, perennial rhizomes; PF, perennial forbs; AB,
4
annuals/biennials.
PB identity
PF identity
AB identity
Absence
Presence
Absence
Presence
Absence
Presence
Absence
Presence
PR
PR+PB
PB
PR+PB
AB
PF+AB
PF
PF+AB
PF
PR+PF
PF
PB+PF
PR
PR+PF
PR
PR+AB
AB
PR+AB
AB
PB+AB
PB
PB+PF
PB
PB+AB
PB+PF
PR+PB+PF
PR+PF
PR+PB+PF
PR+AB
PR+PF+AB
PR+PF
PR+PF+AB
PB+AB
PR+PB+AB
PR+AB
PR+PB+AB
PB+AB
PB+PF+AB
PB+PF
PB+PF+AB
PF+AB
PR+PF+AB
PF+AB
PB+PF+AB
PR+PB
PR+PB+PF
PR+PB
PR+PB+AB
PB+PF+AB PR+PB+PF+AB
5
PR identity
PR+PF+AB PR+PB+PF+AB
PR+PB+AB PR+PB+PF+AB
PR+PB+PF PR+PB+PF+AB
1
Table S3 Soil nematode food resources for nematode trophic groups and variables of below-ground
2
communities used to explain variation in net ecosystem exchange (NEE). BF, bacterial-feeding
3
nematodes; FF, fungal-feeding nematode; PF, plant-feeding nematodes; OC, omnivorous +
4
carnivorous nematodes; FF:BF ratio, ratio of FF to BF nematodes; Ba PLFAs, bacterial PLFAs; Fu PLFAs,
5
fungal PLFAs; F:B ratio, ratio of Fu to Ba PLFAs.
Variables
Nematode food resources
Total nematode abundance (ind. g-1) Total PLFA abundance (nmol g-1)
BF abundance (ind. g-1)
Ba PLFA abundance (nmol g-1)
FF abundance (ind. g-1)
Fu PLFA abundance (nmol g-1)
PF abundance (ind. g-1)
Above-ground plant biomass (g m-2)
OC abundance (ind. g-1)
Ba PLFA abundance (nmol g-1), Fu PLFA abundance (nmol g-1),
BF abundance (ind. g-1), FF abundance (ind. g-1), PF abundance (ind. g-1)
FF:BF ratio
F:B ratio
BF relative abundance (%)
Ba PLFA relative abundance (mol%)
FF relative abundance (%)
Fu PLFA relative abundance (mol%)
PF relative abundance (%)
Above-ground plant biomass (g m-2)
OC relative abundance (%)
NEE (μmol m-2 s-1)
6
7
Ba PLFA relative abundance (mol%), Fu PLFA relative abundance (mol%), BF
relative abundance (%), FF relative abundance (%), PF abundance (ind. g-1)
Total PLFA abundance (nmol g-1), F:B ratio,
Total nematode abundance (ind. g-1), FF:BF ratio
1
Table S4 Simplified results of the effect of PFG identity or PFGs removal on below-ground
2
communities, above-ground plant biomass, soil factors, and NEE using mixed linear models with loss
3
of a specific number of PFGs or individual PFGs (absent or present) as fixed factors and block as a
4
random factor. PFGs: PB, perennial bunchgrasses; PR, perennial rhizomes; PF, perennial forbs; AB,
5
annuals/biennials. Microbes: Ba PLFAs, bacterial PLFAs; Fu PLFAs, fungal PLFAs; F:B ratio, ratio of Fu to
6
Ba PLFAs; Nematodes: BF, bacterial-feeding nematodes; FF, fungal-feeding nematode; PF,
7
plant-feeding nematodes; OC, omnivorous + carnivorous nematodes; FF:BF ratio, ratio of FF to BF
8
nematodes;. NEE, net ecosystem exchange; Soil factors: SOC, soil organic C; TSN, total soil N; PC,
9
principal components. Differences between loss of a specific number of PFGs or the absence and
10
presence of individual PFGs are indicated (*, P<0.05; **, P<0.01; ***, P<0.001).
Variable
PFG richness effects
PFG present or absent effects
Df
F value
Df
PB
PR
PF
AB
F value
F value
F value
F value
Microbes
Total PLFA abundance (nmol g-1)
4
6.272***
1
20.46*** 37.94*** 0.002
0.237
Ba PLFA abundance (nmol
g-1)
4
1.173
1
20.61*** 10.22*** 3.767*
4.451*
Fu PLFA abundance (nmol
g-1)
4
5.439***
1
24.11*** 25.02*** 0.046
0.28
Act PLFA abundance (nmol g-1)
4
8.055***
1
16.61*** 19.87*** 0.822
0.09
Ba PLFA relative abundance (mol%)
4
9.528***
1
5.408*
22.86*** 2.717
1.325
Fu PLFA relative abundance (mol%)
4
0.562
1
0.323
0.085
0.002
0.005
Act PLFA relative abundance (mol%)
4
3.138*
1
0.240
1.679
0.585
0.234
F:B ratio
4
7.518***
1
7.024**
13.14*** 3.43.
1.233
Nematodes
Total nematode abundance (ind. g-1)
4
4.759**
1
24.47*** 16.49*** 0.033
1.032
g-1)
4
4.787*
1
17.04*** 22.75*** 0.375
8.004**
FF abundance (ind. g-1)
4
7.941***
1
20.02*** 4.212*.
1.386
1.467
PF abundance (ind. g-1)
4
4.03**
1
7.042**
3.441*
0.334
4.833*
OC abundance (ind. g-1)
4
4.926**
1
10.34**
4.359*
1.487
0.408
BF relative abundance (%)
4
2.265
1
0.144
1.7
2.494
27.04***
FF relative abundance (%)
4
4.311*
1
0.528
1.974
3.216.
15.46***
PF relative abundance (%)
4
1.676
1
0.147
0.872
0.114
16.32***
OC relative abundance (%)
4
2.128
1
0.162
0.056
1.169
3.886*
BF abundance (ind.
FF:BF ratio
4
5.212*
1
0.422
4.111*
3.920*
24.91***
Above-ground plant biomass and soil factors
Above-ground plant biomass (g m-2)
4
9.942***
1
34.55*** 13.01*** 0.321
0.022
Soil moisture (%)
4
12.78***
1
17.05*** 15.42*** 3.940*
1.212
NO3--N (mg kg-1)
4
7.479***
1
0.628
NH4+-N
4
5.793***
1
18.65*** 0.976
2.527
4.134*
Soil pH
4
0.08
1
3.265
1.133
1.004
0.057
SOC (g kg-1)
4
0.511
1
0.882
1.58
1.933
1.501
TSN (mg kg-1)
4
3.002
1
3.913
0.092
2.243
1.244
SOC:TSN ratio
4
0.374
1
0.185
0.001
1.394
0.019
PC1 of soil factors
4
8.986***
1
8.433**
2.425
11.3**
1.987
PC2 of soil factors
4
5.035**
1
0.987
16.13*** 4.154*
0.478
4
16.68***
1
12.81*** 12.92*** 3.191
(mg
kg-1)
NEE (μmol m-2 s-1)
1
9.419**
8.746** 0.002
1.325
1
Table S5 Results of principal components analysis (PCA) of soil properties. SOC, soil organic C; TSN,
2
total soil N. Statistics (r and P values) for linear relationships between variable and principal
3
components are indicated (*, P<0.05; **, P<0.01; ***, P<0.001).
Soil property
4
5
PC1
PC2
Soil moisture (%)
-0.276*
-0.614***
NO3--N (mg kg-1)
0.468***
0.627***
NH4+-N (mg kg-1)
0.313**
0.069
Soil pH
-0.083
0.570***
SOC (g kg-1)
0.949***
-0.188
TSN (mg kg-1)
0.828***
-0.347**
SOC:TSN ratio
0.477***
0.059
Cumulative (%)
32
18
1
Table S6 Simplified results of the effect of plant functional group (PFG) richness, above-ground plant biomass, PFG component, nematode food resource
2
(soil microbes), and soil factors on below-ground communities using mixed linear models with loss of a specific number of PFGs or individual PFGs
3
(absent or present) as fixed factors and block as a random factor. PFGs: PB, perennial bunchgrasses; PR, perennial rhizomes; PF, perennial forbs; AB,
4
annuals/biennials. Microbes: Ba PLFAs, bacterial PLFAs; Fu PLFAs, fungal PLFAs; F:B ratio, ratio of Fu to Ba PLFAs; Nematodes: BF, bacterial-feeding
5
nematodes; FF, fungal-feeding nematode; PF, plant-feeding nematodes; OC, omnivorous + carnivorous nematodes; FF:BF ratio, ratio of FF to BF
6
nematodes;. NEE, net ecosystem exchange; Soil factors: SOC, soil organic C; TSN, total soil N; PC, principal components. Significant P values are indicated
7
(*, P<0.05; **, P<0.01; ***, P<0.001). Variables in the brackets in the nematodes indicate the potential nematode foods. #, above-ground plant biomass
8
was an indicator of the food resources of plant-feeding nematodes.
Variable
PFG richness
Above-ground plant
biomass (g m-2)
PFG component
PC1 of soil factors
PC2 of soil factors Food resources
df
1
1
14
1
1
Total PLFA abundance (nmol g-1)
49.76***
30.66***
6.48***
1.27
0.95
Ba PLFA abundance (nmol g-1)
5.63*
42.39***
10.16***
4.7*
1.23
46.08***
41.67***
5.52***
0.02
0.37
36.14***
13.54***
4.14***
0.46
0.01
Ba PLFA relative abundance (mol%)
32.44***
5.74*
1.71
0.07
0.22
Fu PLFA relative abundance (mol%)
0.05
0.54
0.88
0.71
1.52
Act PLFA relative abundance (mol%)
0.02
1.35
3.07***
0.49
1.55
F:B ratio
39.81***
8.21**
3.47***
1.29
2.57
Microbes
Fu PLFA abundance (nmol
g-1)
Act PLFA abundance (nmol
Nematodes
g-1)
Total nematode abundance (ind. g-1)
5.97*
25.42***
5.67***
0.01
0.07
83.77***(Total PLFA abundance)
9.38**
23.5***
9.87***
0.49
2.85
101.15***(Ba PLFA abundance)
FF abundance (ind. g-1)
20.28***
6.32*
5.15***
2.38
0.5
33.13***(Fu PLFA abundance)
PF abundance (ind. g-1)
19.33***
20.9***
2.42**
0.01
1.72
20.9***(Above-ground plant biomass)#
BF abundance (ind.
g-1)
OC abundance (ind. g-1)
2.69
0.54
0.57
0.95
0.36
10.18**(Ba PLFA abundance)
4.94*(Fu PLFA abundance)
14.29***(BF abundance)
10.76**(FF abundance)
4.39*(PF abundance)
BF relative abundance (%)
25.36***
0.25
5.56***
0.06
6.23*
0.32(Ba PLFA relative abundance)
FF relative abundance (%)
12.13***
5.99*
4.4***
4.06
1.26
6.15*(Fu PLFA relative abundance)
PF relative abundance (%)
3.3
0.46
3.84***
0.09
4.3*
0.46(Above-ground plant biomass)#
OC relative abundance (%)
0.79
3.2
1.09
0.60
1.71
9.1***(Ba PLFA relative abundance)
11.1**(Fu PLFA relative abundance)
9.06**(BF relative abundance)
7.45**(FF relative abundance)
9.99**(PF relative abundance)
FF:BF ratio
23.4***
0.9
7.05***
0.47
6.62*
0.03(F:B ratio)
1
Table S7 Bivariate correlations between below-ground communities or NEE with soil factors.
2
Microbial community: Ba PLFAs, bacterial PLFAs; Fu PLFAs, fungal PLFAs; Act PLFAs, actinobacterial
3
PLFAs; F:B ratio, ratio of Fu to Ba PLFAs. Nematode community: BF, bacterial-feeding nematodes; FF,
4
fungal-feeding nematode; PF, plant-feeding nematodes; OC, omnivorous + carnivorous nematodes;
5
FF:BF ratio, ratio of FF to BF nematodes; NEE, net ecosystem exchange. Asterisks indicate the strength
6
of linear relationships for pairwise comparisons (*, P<0.05; **, P < 0.01; ***, P < 0.001).
Soil
moisture Soil pH
(%)
Soil
Soil
Soil NO3--N
Total soil SOC:TSN
+-N
NH
organic C
4
(mg kg-1)
N (g kg-1) ratio
-1
-1
(mg kg ) (g kg )
Total PLFA abundance (nmol g-1)
0.318**
-0.021
-0.129
-0.306** -0.098
-0.104
-0.039
Ba PLFA abundance (nmol g-1)
0.162
0.025
-0.046
-0.120
-0.084
-0.061
-0.049
Fu PLFA abundance (nmol g-1)
0.357**
0.142
-0.018
-0.200
-0.017
-0.006
-0.134
Act PLFA abundance (nmol g-1)
0.459*** 0.211
-0.152
-0.213
-0.072
-0.144
0.062
F:B ratio
0.337**
0.161
0.028
-0.263*
0.045
0.020
-0.105
Ba PLFA relative abundance (mol%)
-0.322** 0.071
0.143
0.320**
0.039
0.082
-0.031
Fu PLFA relative abundance (mol%)
0.085
0.232*
0.157
0.140
0.083
0.128
-0.139
Act PLFA relative abundance (mol%)
0.107
0.268*
0.036
0.127
0.019
-0.021
0.095
Total nematode abundance (ind. g-1) 0.362*** 0.117
-0.094
-0.185
-0.094
-0.053
0.001
BF abundance (ind. g-1)
0.296**
0.103
-0.089
-0.136
-0.028
0.055
-0.044
FF abundance (ind. g-1)
0.364*** 0.097
-0.119
-0.204
-0.198
-0.273*
0.044
PF abundance (ind. g-1)
0.221*
0.023
0.048
-0.082
-0.220*
-0.101
0.023
OC abundance (ind. g-1)
0.273*
0.140
-0.084
-0.207
0.063
-0.007
0.085
FF:BF ratio
0.129
-0.020
-0.018
-0.027
-0.207
-0.298** 0.031
BF relative abundance (%)
-0.119
-0.017
-0.030
0.018
0.188
0.250*
FF relative abundance (%)
0.146
-0.016
-0.080
-0.026
-0.247*
-0.365*** 0.000
PF relative abundance (%)
0.004
-0.062
0.153
0.055
-0.226*
-0.115
0.011
OC relative abundance (%)
0.090
0.134
0.004
-0.072
0.133
0.012
0.122
NEE (μmol m-2 s-1)
-0.475**
-0.057
0.075
0.227
-0.058
0.002
0.007
Variables
Microbes
Nematodes
7
-0.055
2
-1
-1
Soil NH4 -N (mg kg )
12
15
18
+
-
8
Soil NO3 -N (mg kg )
2
Soil pH
7
Soil moisture (%)
12
16
-2
4
Aboveground biomass (g m )
70
140
(d)
(i)
Control
PB
PR
PF
AB
PR+PB
PF+PB
AB+PB
PF+PR
AB+PR
AB+PF
PF+PR+PB
AB+PR+PB
AB+PF+PR
AB+PF+PB
PF+PR+PB+AB
PC2 of soil factors
0
(h)
-2
2 0
6
3 8
0
(c)
Control
PB
PR
PF
AB
PR+PB
PF+PB
AB+PB
PF+PR
AB+PR
AB+PF
PF+PR+PB
AB+PR+PB
AB+PF+PR
AB+PF+PB
PF+PR+PB+AB
PC1 of soil factors
0
(g)
-2
SOC:TSN ratio
8
10
-1
Total soil nitrogen (g kg )
2
-1
Soil organic carbon (g kg )
18
27
(b)
Control
PB
PR
PF
AB
PR+PB
PF+PB
AB+PB
PF+PR
AB+PR
AB+PF
PF+PR+PB
AB+PR+PB
AB+PF+PR
AB+PF+PB
PF+PR+PB+AB
6
1
9
(f)
Control
PB
PR
PF
AB
PR+PB
PF+PB
AB+PB
PF+PR
AB+PR
AB+PF
PF+PR+PB
AB+PR+PB
AB+PF+PR
AB+PF+PB
PF+PR+PB+AB
Control
PB
PR
PF
AB
PR+PB
PF+PB
AB+PB
PF+PR
AB+PR
AB+PF
PF+PR+PB
AB+PR+PB
AB+PF+PR
AB+PF+PB
PF+PR+PB+AB
1
(a)
(e)
(j)
2
Fig. S1 Responses of above-ground plant biomass and soil properties to removal of plant functional groups (PFGs). SOC:TSN ratio, ratio of soil organic C
3
to total soil N; PC, principal components. PFGs: PB, perennial bunchgrasses; PR, perennial rhizomes; PF, perennial forbs; AB, annuals/biennials. Bars
4
represent the means (+ SE).
ns
ns
7.7
***
6.3
**
ns
ns
***
*
ns
ns
AB
PF
PB
PR
AB
PF
PB
PR
AB
PF
PB
PR
6.0
PF
AB
PR
PB
PC2 of soil factors
0.0
0.5
(j)
***
-0.5
ns ns ns ns
PC1 of soil factors
0.0
0.5
(i)
-0.5
SOC:TSN ratio
7.5
9.0
ns ns ns ns
0.9
PF
AB
PR
PB
0
8
1.5
(h)
(g)
-1
Total soil nitrogen (g kg )
1.8
2.7
ns ns ns ns
ns ns ns ns
ns ns *
Soil pH
7.0
-1
** **
(e)
+
* ns
Soil NH4 -N (mg kg )
12
16
15
2.5
-1
*** ***
0
-1
Soil organic carbon (g kg )
10
20
(f)
1
(d)
(c)
-
ns ns
Soil NO3 -N (mg kg )
2.0
***
(b)
9
***
Soil moisture (%)
12
-2
Aboveground bomass (g m )
50
100
+
(a)
2
Fig. S2 Responses of above-ground plant biomass and soil properties to removal of individual plant
3
functional groups (PFGs). -, absence of PFG; +, presence of PFG. SOC:TSN ratio, ratio of soil organic C
4
to total soil N; PC, principal components. PFGs: PB, perennial bunchgrasses; PR, perennial rhizomes;
5
PF, perennial forbs; AB, annuals/biennials. Bars represent the means (+ SE). Differences between the
6
absence and presence of individual PFGs are indicated (ns, P>0.05; *, P<0.05; **, P<0.01; ***,
7
P<0.001).
(d)
20
3.0
8
20
(c)
(b)
-2
Aboveground biomass (g m )
60
120
(a)
6
SOC:TSN ratio
8
-1
1
0 1 2 3 4
1
0 1 2 3 4
-1
Soil NH4 -N (mg kg )
10
0 1 2 3 4
ab
b ab
+
0
b
ab
1.2
(i)
PC1 of soil factors
-1.2
0.0
Total soil nitrogen (g kg )
2
10
(h)
a
(j)
b
PC2 of soil factors
-1.2
0.0
1.2 0.0
6
(g)
a
-
Soil pH
7
a
3 0
0
(f)
b
-1
Soil moisture (%)
10
b
a
-1
Soil organic carbon (g kg )
12
18
24
Soil NO3 -N (mg kg )
1.5
c
b
(e)
a
a
0 1 2 3 4
0 1 2 3 4
PFG richness loss
2
Fig. S3 Responses of above-ground plant biomass and soil factors to the removal of plant functional
3
groups (PFGs). SOC:TSN ratio, ratio of soil organic C to total soil N; PC, principal components. Bars
4
represent the means (+ SE). Different letters indicate significant differences among the richness of
5
plant functional groups (one-way ANOVA, P<0.05).
-1
**
* ns *
0.0
ns ns ns
(f)
+
***
ns ns ns
ns ns ns *
PF
AB
PR
PB
PF
AB
PR
PB
0
PF
AB
PR
PB
PF abundance (ind. g )
0.6
1.2
ns
0
ns ns
PF relative abundance (%)
8
16
-1
OC abundance (ind. g )
0.6
1.2
** *
(c)
+
(e)
(d)
0.0
1
(b)
OC relative abundance (%)
8
16
ns ns
Act PLFA relative abundance (mol%)
5
6
7
*** ***
1.0
-1
Act PLFA abundance (nmol g )
1.5
2.0
+
(a)
2
Fig. S4 Responses of below-ground communities (a-b, microbes; c-f, nematodes) to the removal of
3
individual plant functional groups (PFGs). -, absence of the indicated PFG; +, presence of the
4
indicated PFG. Act PLFAs, actinobacterial PLFAs; PF, plant-feeding nematodes; OC, omnivorous +
5
carnivorous nematodes. PFGs: PB, perennial bunchgrasses; PR, perennial rhizomes; PF, perennial
6
forbs; AB, annuals/biennials. Bars represent the means (+ SE). Differences between the absence and
7
presence of individual PFG are indicated (ns, P>0.05; *, P<0.05; **, P<0.01; ***, P<0.001).
-1
Ba PLFA abundance (nmol g )
12
16
20
-1
Fu PLFA abundance (nmol g )
Fu PLFA relative abundance (mol%)
0.0
0.6
1.2
1.8
2.7
3.6
(f)
Act PLFA relative abundance (mol%)
Act PLFA abundance (nmol g )
0
5
10
0.9
1.8
2.7
(g)
-1
(c)
Control
PB
PR
PF
AB
PR+PB
PF+PB
AB+PB
PF+PR
AB+PR
AB+PF
PF+PR+PB
AB+PR+PB
AB+PF+PR
AB+PF+PB
PF+PR+PB+AB
0.06
-1
Total PLFA abundance (nmol g )
0
20
40
(b)
Control
PB
PR
PF
AB
PR+PB
PF+PB
AB+PB
PF+PR
AB+PR
AB+PF
PF+PR+PB
AB+PR+PB
AB+PF+PR
AB+PF+PB
PF+PR+PB+AB
Control
PB
PR
PF
AB
PR+PB
PF+PB
AB+PB
PF+PR
AB+PR
AB+PF
PF+PR+PB
AB+PR+PB
AB+PF+PR
AB+PF+PB
PF+PR+PB+AB
F:B ratio
0.04
(e)
Ba PLFA relative abundance (mol%)
40
60
80
0.02
Control
PB
PR
PF
AB
PR+PB
PF+PB
AB+PB
PF+PR
AB+PR
AB+PF
PF+PR+PB
AB+PR+PB
AB+PF+PR
AB+PF+PB
PF+PR+PB+AB
1
(a)
(d)
(h)
2
Fig. S5 Response of soil microbes to the removal of plant functional groups (PFGs). Microbial community: Ba PLFAs, bacterial PLFAs; Fu PLFAs, fungal
3
PLFAs; Act PLFAs, actinobacterial PLFAs; F:B ratio, ratio of Fu to Ba PLFAs. Bars represent the means (+ SE).
0
OC relative abundance (%)
10
20
0.0
0.0
PF abundance (ind. g-1)
0.9
1.8
OC abundance (ind. g-1)
0.8
1.6
(d)
(i)
Control
PB
PR
PF
AB
PR+PB
PF+PB
AB+PB
PF+PR
AB+PR
AB+PF
PF+PR+PB
AB+PR+PB
AB+PF+PR
AB+PF+PB
PF+PR+PB+AB
(h)
PF relative abundance (%)
15
30
FF abundance (ind. g-1)
2
BF abundance (ind. g-1)
5
(c)
Control
PB
PR
PF
AB
PR+PB
PF+PB
AB+PB
PF+PR
AB+PR
AB+PF
PF+PR+PB
AB+PR+PB
AB+PF+PR
AB+PF+PB
PF+PR+PB+AB
0
4
10
Total nematode abundance (ind. g-1)
0
5
10
FF relative abundance (%)
20
40 0
(g)
0
0
1.0
BF relative abundance (%)
50
75
FF:BF ratio
0.5
(b)
Control
PB
PR
PF
AB
PR+PB
PF+PB
AB+PB
PF+PR
AB+PR
AB+PF
PF+PR+PB
AB+PR+PB
AB+PF+PR
AB+PF+PB
PF+PR+PB+AB
25
0.0
(f)
Control
PB
PR
PF
AB
PR+PB
PF+PB
AB+PB
PF+PR
AB+PR
AB+PF
PF+PR+PB
AB+PR+PB
AB+PF+PR
AB+PF+PB
PF+PR+PB+AB
Control
PB
PR
PF
AB
PR+PB
PF+PB
AB+PB
PF+PR
AB+PR
AB+PF
PF+PR+PB
AB+PR+PB
AB+PF+PR
AB+PF+PB
PF+PR+PB+AB
1
(a)
(e)
(j)
2
Fig. S6 Response of soil nematodes to the removal of plant functional groups (PFGs). Nematode community: BF, bacterial-feeding nematodes; FF,
3
fungal-feeding nematode; PF, plant-feeding nematodes; OC, omnivorous + carnivorous nematodes; FF:BF ratio, ratio of FF to BF nematodes. Bars
4
represent the means (+ SE).
a
b
ab
a
0 1 2 3 4
1
-1
b ab
a
(e)
0
0.0
-1
OC abundance (ind. g )
0.7
1.4
(d) r2=0.147***
b
ab
b
ab
a
0 1 2 3 4
(f) r2=0.076*
0
ab
PF abundance (ind. g )
0.6
1.2
b bc
(c) r2=0.141***
(b)
OC relative abundance (%)
10
20 0.0
c
PF relative abundance (%)
Act PLFA relative abundance (mol%)
5
10
10
20 0
-1
Act PLFA abundance (nmol g )
0.0
1.5
3.0
(a) r2=0.210***
0 1 2 3 4
0 1 2 3 4
PFG richness loss
2
Fig. S7 Responses of below-ground communities (a-b, microbes; c-f, nematodes) to the removal of
3
plant functional groups (PFGs). Act PLFAs, actinobacterial PLFAs; PF, plant-feeding nematodes; OC,
4
omnivorous + carnivorous nematodes. Bars represent the means (+ SE). Different letters indicate
5
significant differences among the richness of plant functional groups (One-way ANOVA, P<0.05).
0
50 100 150
-1
PF abundance (ind. g )
0.9
1.8
(c) r2=0.271***
(f)
0
0
0.0
OC relative abundance (%)
12
24 0.0
Act PLFA relative abundance (mol%)
4
8
12
PF relative abundance (%)
12
24
-1
Act PLFA abundance (nmol g )
1
2
3
(b)
(e)
(d) r2=0.218***
-1
OC abundance (ind. g )
0.9
1.8
(a) r2=0.228***
0
50 100 150
0
50 100 150
-2
Aboveground plant biomass (g m )
1
2
Fig. S8 Relationships between below-ground communities (a-b, microbes; c-f, nematodes) and
3
above-ground plant biomass. Act PLFAs, actinobacterial PLFAs; PF, plant-feeding nematodes; OC,
4
omnivorous + carnivorous nematodes. Regression was estimated using a linear or quadratic model
5
with above-ground plant biomass as a continuous predictor. Statistics (r2 and P values) for regression
6
are indicated (***, P<0.001).
7
9
(b) r2=0.304***
(c) r2=0.154***
0.0
-1
-1
FF abundance (ind. g )
1.5
3.0
BF abundance (ind. g )
3
6
-1
Total nematode abundance (ind. g )
5
10
15
(a) r2=0.331***
0
-1
0
0
70
140
-2
Aboveground plant biomass (g m )
OC abundance (ind. g )
1
OC abundance (ind. g )
1
-1
0.0
-1
PF abundance (ind. g )
0.9
1.8
(f) r2=0.293***
(e) r2=0.256***
(d) r2=0.271***
1
2
2
10
15
20
0.6
0.9
24
36
-1
Total PLFA abundance (nmol g ) Ba PLFA abundance (nmol g-1) Fu PLFA abundance (nmol g-1)
0
4
8
-1
BF abundance (ind. g )
0.0
1.5
3.0
-1
FF abundance (ind. g )
2
Fig. S9 Relationships between nematode abundance and nematode resources (soil microbes). PLFA,
3
phospholipid fatty acid; Ba PLFAs, bacterial PLFAs; Fu PLFAs, fungal PLFAs; BF, bacterial-feeding
4
nematodes; FF, fungal-feeding nematode; PF, plant-feeding nematodes; OC, omnivorous +
5
carnivorous nematodes. Regressions are based on linear or quadratic models. Statistics (r2 and P
6
values) for regression are indicated (***, P<0.001).