Electronic supplementary material
Table S1 Plant functional traits of different abundance classes.
See separate document.
Table S2 Repeated measures analysis with mixed linear model (PROC MIXED) for
species richness response ratio using N-treatment (N), year (Y) and the interaction as
fixed effects.
Response
Term
All species
N
Y
N×Y
N
Y
N×Y
N
Y
N×Y
Common species
Rare species
F
P
39.97
9.56
1.87
25.88
14.54
2.79
26.81
7.13
2.20
<0.0001
<0.0001
0.0176
<0.0001
<0.0001
0.0002
<0.0001
0.0003
0.0037
Table S3 Comparisons of trait value and trait plasticity between species with positive and negative response of relative biomass to N.
Trait value
Trait plasticity
Species
Nmass
C:N
SLR
Pn
RSR
SRL2
SRL3
RA
Life
history
Nmass
Narea
Positive response
A. amaranthoides
C. glaucum
L. chinensis
Mean
Negative response
A. sibiricum
A. cristatum
C. korshinskyi
S. grandis
Mean
34.39
41.01
25.07
33.49
13.47
11.63
19.22
14.78
4.35
6.10
0.65
3.70
25.67
29.04
16.50
23.74
0.11
0.09
0.28
0.16
117.38
121.32
113.47
117.39
32.17
34.51
23.38
30.02
22.96
25.72
21.36
22.62
23.16
20.24
17.82
21.04
21.50
20.15
1.85
0.44
0.24
0.42
0.74
13.33
9.14
11.72
7.50
10.42
0.32 93.44
0.35 109.09
0.75 107.24
0.68 90.27
0.53 100.01
18.55
16.42
20.26
19.55
18.70
2.42
5.56
0.00
3.04
2.76
P
0.05
0.05
0.09
0.01
0.01
0.05
0.05
0.03
49.72 Annual
38.41 Annual
0.25† Perennial
29.46
0.12
0.15
0.20
0.16
0.15
0.18
0.12
0.15
Perennial
Perennial
Perennial
Perennial
0.22
0.21
0.23
0.21
0.22
0.21
0.24
0.26
0.16
0.22
0.09
0.03
0.07
Note: General linear model (GLM) was used to compare continuous traits between species with positive and negative responses, and
the Chi-square test was used for the categorical traits. RSR= root: shoot biomass ratio, SRL2= specific root length (second order),
SRL3= specific root length (third order), SLR = stem: leaf biomass ratio, RA = reproductive allocation, Pn = net photosynthetic rate,
Nmass = mass based leaf N content. †: L. chinensis is a perennial rhizome grass, and the dominant dispersal mode is rhizome with
rhizome biomass accounting for 30% of the total plant biomass (unpublished data).
Trait plasticity index (TPI) was calculated as in Godoy et al [1].
1
Godoy, O., Valladares, F. & Castro-Díez, P. 2011 Multispecies comparison reveals
that invasive and native plants differ in their traits but not in their plasticity. Funct.
Ecol. 25, 1248-1259. (doi:10.1111/j.1365-2435.2011.01886.x)
Supplementary Figures
Figure S1 Effects of N addition on total community aboveground biomass during 2005 to
2009 (error bars denote SEM). Bars with the same letter were not significantly different
in Duncan’s multiple range tests reported from one-way ANOVA. Regression parameters
were estimated each year using linear model with N treatment as a continuous predictor,
i.e., Aboveground biomass = Intercept+ Slope × N. Slopes were further tested across five
years (inset), and bars with the same letters were not significantly different in Ordinary
Least Square (OLS) test (P > 0.05).
100
Slope
A
A
50
B
BC
C
2009
2008
a
300
200
b
ab
bc
b
ab
d cd
c
a
b
cd
d
d
2005
2006
2007
Year
2008
28.00
1.75
10.50
28.00
Control
1.75
10.50
Control
28.00
10.50
1.75
Control
28.00
10.50
1.75
Control
0
abc
abc
bc
c
Control
bc
100
bc
2009
28.00
ab
ab
a
1.75
ab
a
a
10.50
2005
2007
0
400
2006
500
-2
Aboveground biomass (g m )
600
Figure S2 Responses of common species to N addition (error bars denote SEM). Bars
with the same letter were not significantly different in Duncan’s multiple range tests
reported from one-way ANOVA. For each species, aboveground biomass for each
treatment was the average of nine replicates during 2007 to 2009. Species abbreviations:
Ac, Agropyron cristatum; Sg, Stipa grandis; As, Archnasrum sibiricum; Ck, Carex
korshinskyi; Aa, Axyris amaranthoides; Cg, Chenopodium glaucum; and Lc, Leymus
chinensis.
(a) 80
60
a
40
a
a
a
ab
abc abc
20
b
b
a
b
ab
c bc
ab
b
(b) 0
A. cristatum
S. grandis
A. sibiricum
200
b
C. korshinskyi
a
150
100
a
50
b
a
ab
bc
c
bc
c
1.75
10.50
28.00
ab
Control
b
b
C. glaucum
A. amaranthoides
L. chinensis
N addition rate (g N m-2 yr-1)
1.75
10.50
28.00
Control
28.00
1.75
10.50
Control
1.75
10.50
28.00
0
Control
Aboveground biomass (g m-2)
a