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SUPPORTING INFORMATION
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Table S1. Characterization of different ecosystem types
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Characterization of different ecosystem types considered for the study of the links between plant functional diversity and C storage in
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the semiarid Chaco of central Argentina, including soil (30 cm depth) and general vegetation structure. Values represent mean and
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standard deviation (in braquets) for each ecosystem type. Values followed by the same letter in a given row are not significantly
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different at P ≤ 0.05 (LSD Fisher), number or replicates was 4 in all cases.
Primary forest
No significant logging or
livestock grazing in the
past 7 and 5 decades,
respectively
Land-use regime
Secondary forest
Current light selective
logging and low cow and
goat stocking rate
Closed species-rich
shrubland
Current moderate to
heavy logging and
moderate-high cow and
goat stocking rate
Open Larrea shrubland
Heavy logging and high
cow and goat stocking
rate during past decades,
now decreasing due to
declining productivity
Soil properties
pH
6.99 ± 0.19a
6.98 ± 0.80a
7.33 ± 0.43a
7.20 ± 0.25a
Sand (%)
61.55 ± 2.02a
60.48 ± 1.44a
57.21 ± 6.40a
56.97 ± 8.09a
Silt (%)
29.27 ± 2.33a
28.04 ± 2.16a
30.61 ± 4.90a
32.83 ± 6.92a
Clay (%)
9.56 ± 0.71ab
11.23 ± 1.05bc
11.44 ± 1.13c
9.09 ± 1.57a
Bulk density (g cm-3)
1.38 ± 0.10a
1.52 ± 0.04b
1.54 ± 0.07b
1.56 ± 0.10b
Vegetation structure
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43.7 ± 11.1ab
50 ± 18.3a
27.5 ± 15.0bc
16.2 ± 2.5c
Shrub cover (%)
78.7 ± 6.3a
68.7 ± 10.3ab
71.2 ± 8.5ab
60.0 ± 17.8b
Herbaceous cover (%)
70.0 ± 4.0ab
60.0 ± 7.1ab
72.5 ± 5.0a
56.2 ± 17.0b
Bare soil (%)
30.0 ± 4.1ab
40.0 ± 7.1b
20 ± 7.1a
43.7 ± 17.0b
Maximum tree height (cm)
1263 ± 50a
1232 ± 93a
761 ± 199b
518 ± 65c
Maximum tree DBH (cm)
54.3 ± 4.7a
37.7 ± 3.4b
33.0 ± 7.1bc
25.6 ± 4.4c
37 ± 3a
30 ± 4a
33 ± 8a
37 ± 8a
Herbaceous biomass (Mg ha-1)**
0.94 ± 0.28a
0.52 ± 0.32a
1.64 ± 1.56ab
2.9 ± 0.3b
Shrub biomass (Mg ha-1)**
25.6 ± 4.0a
20.4 ± 5.4ab
19.2 ± 4.8ab
15.8 ± 9b
Tree biomass (Mg ha-1)**
77.9 ± 15.5a
67.66 ± 27.4a
22.24 ± 11.68b
Tree cover (%)
Species number*
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20.02
12.24b
* See Table S4 for list of dominant species.
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** Biomass variables showed here were estimated on the basis of basal area (tree biomass), crown area (shrub biomass) and direct weighting of
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plant material (herbaceous biomass) and are presented a part of the general characterization. They were not used in the calculation of species
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abundance for the calculation functional diversity indices.
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Table S2. Summary of predictor and response variables
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deviation; N = number of replicates
Summary of variables used in the quantification of functional diversity and carbon storage, in alphabetical order. SD = standard
Variables
Units
N
Mean
SD
Height (H)
cm
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197.97
74.41
Leaf dry matter content (LDMC)
mg g-1
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477.87
25.54
Leaf nitrogen concentration (LNC)
mg g-1
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2.51
0.19
Leaf toughness (LT)
N mm-1
16
1.6
0.42
Specific leaf area (SLA)
mm2 mg-1
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10.32
1.45
Wood specific gravity (WSG)
g cm-3
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0.62
0.12
Height (H)
unitless
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0.85
0.09
Leaf dry matter content (LDMC)
unitless
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0.27
0.15
Leaf nitrogen concentration (LNC)
unitless
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0.28
0.12
Leaf toughness (LT)
unitless
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0.76
0.16
Specific leaf area (SLA)
unitless
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0.57
0.15
Wood specific gravity (WSG)
unitless
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0.61
0.2
unitless
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0.81
0.06
C in aboveground standing biomass (AGB)
Mg C ha-1
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19.51
7.36
C in aboveground litter (AL)
Mg C ha-1
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3.25
2.24
Community weighted means (CWM)
Single-trait functional divergence indices (FDvar)
Multi-trait functional divergence index
FDiv
C stocks
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Soil organic carbon (SOC)
Mg C ha-1
15*
37.87
10.32
Total ecosystem carbon (TEC)
Mg C ha-1
15*
60.84
18.41
*soil sample for one site was misplaced during the laboratory procedure
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Figure S1. Comparison of tree aboveground dry biomass estimates
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dotted gray line represents a 1:1 theoretical relationship; the dotted black line represents the observed relationship. * Model proposed
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by Chave et al. (2005) for dry forests; ** model proposed by Brown (1997) for dry climatic zones.
Comparison of the individual tree biomass estimated with Brown’s (1997) equation and Chave et al.’s (2005) dry forest equation. The
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Table S4. Dominant species and their trait values used to calculate community functional indices
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(FDvar and FDiv). Species are listed in decreasing order of abundance (% cover, see main text) across the whole study area. H:
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height, LDMC: leaf dry matter content, LNC: leaf nitrogen concentration, LT: leaf toughness, SLA: specific leaf area, and WSG: wood
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specific content. Letters in bracket next to growth forms indicate leaf periodicity, D: deciduous; E: evergreen; SE: semi-deciduous;
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non-woody species are absent (annuals) or die back (perennials) during the dry season. Nomenclature followed Zuloaga & Morrone
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(1996; 1999) and their regular on-line updates at http://www2.darwin.edu.ar/Proyectos/FloraArgentina/FA.asp
List of dominant species and their trait values used to calculate community weighted mean (CWM) and functional divergence indices
Family name
Growth form
H
(cm)
LDMC
(mg g-1)
LNC
(mg g-1)
WSG*
(g cm-3)
Mean % cover
and SD
Zygophyllaceae
Shrub (E)
167
600
22.95
0.9
5.93
0.9
17.29 (11.56)
Mimozyganthus carinatus
Fabaceae
Shrub (E)
154
587
19.59
0.5
9.66
0.96
11.08 (6.44)
Aspidosperma quebrachoblanco
Apocynaceae
Tree (E-SD)
700
569
16.71
4.98
5.09
0.78
8.10 (8.09)
Acacia gilliesii
Fabaceae
Shrub (D)
169
419
43
0.44
15.03
0.78
6.73 (6.0)
Prosopis flexuosa
Fabaceae
Tree (D)
414
397
32.77
1.26
14.63
0.8
4.98 (3.53)
Celtidaceae
Shrub (D)
153
341
33.9
0.43
14.43
0.64
4.77 (5.19)
Selaginella sellowii
Selaginellaceae
Fern
5
410
30.8
3.29
9.32
0
4.72 (6.24)
Cordobia argentea
Malpighiaceae
Climber (D)
117
371
27.9
0.41
13.45
0
3.28 (4.65)
Poaceae
Grass
55
462
18.87
1.73
12.97
0
2.82 (4.80)
Capparis atamisquea
Capparaceae
Shrub (D)
178
529
25.81
1.03
7.44
0.85
2.21 (2.62)
Justicia squarrosa
Acanthaceae
Forb (E)
32
228
35.1
0.49
28.92
0
2.19 (3.99)
Species name
Larrea divaricata
Celtis erhembergiana
Trichloris crinita
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LT
SLA
(N mm-1) (mm2 mg-1)
Tricomaria usillo
Malpighiaceae
Shrub (D)
82
250
18.8
1
16.77
0.7
2.03 (3.92)
Setaria pampeana
Poaceae
Grass
38
261
23.6
2.85
21.62
0
2.02 (1.53)
Bouteloua aristidoides
Poaceae
Grass
4
491
15.93
2.76
13.98
0
1.83 (5.48)
Celastraceae
Shrub (E-SD)
161
525
25.3
0.71
5.3
0.73
1.77 (2.10)
Pappohorum caespitosum
Poaceae
Grass
42
351
15.2
5.12
10.15
0
1.75 (1.98)
Gouinia paraguayensis
Poaceae
Grass
47
401
23.1
3.41
19.71
0
1.51 (2.79)
Condalia microphylla
Rhamnaceae
Shrub (E-SD)
137
450
32.6
0.31
10.81
0.97
1.49 (2.34)
Bromelia urbaniana
Bromeliaceae
Bromelioid (E)
22
277
9.15
5.89
1.98
0
1.41 (2.38)
Geoffroea decorticans
Fabaceae
Tree (D)
424
390
25.1
1.37
11.18
0.52
1.24 (2.06)
Neobouteloua lophostachia
Poaceae
Grass
9
345
28.9
2.87
13.24
0
1.12 (1.66)
Cercidium praecox
Fabaceae
Tree (D)
323
348
39.9
0.66
13.14
0.54
0.92 (1.58)
Aristida mendocina
Poaceae
Grass
47
452
23.9
4.91
12.66
0
0.80 (1.42)
Opuntia sulphurea
Cactaceae
Stem
Succulent (E)
38
125
11.8
2.16
2.88
0
0.70 (1.31)
Tephrocactus articulatus
Cactaceae
Stem
Succulent (E)
30
195
14
1.86
3.38
0
0.61 (1.55)
Portulaca oleraceae
Portulacaceae
Leaf
succulent forb
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75
29.9
0.42
15.31
0
0.55 (1.52)
Aloysia gratissima
Verbenaceae
Shrub (D)
93
364
38.3
0.45
14.76
0.79
0.26 (0.54)
Moya spinosa
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*Because zero values preclude the calculation of the functional divergence index (FDvar), a very small conventional value of WSG (0.2 g cm -3) was
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assigned to all herbaceous species in order to calculate the FDvar WSG of the plant communities.
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Table S5. Pairwise associations between C stocks and functional diversity components
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Pairwise associations between the magnitude of C stocks and functional diversity
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components in different ecosystems of the semiarid Chaco of central Argentina. Values
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indicate the regression coefficients (R2) from simple linear regression analysis, indicated
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with asterisks if statistically significant (*: P < 0.05; **: P < 0.01; ***: P < 0.001, ns: not
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significant). Relationships showing a negative slope are indicated with negative signs. H:
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height, LDMC: leaf dry matter content, LNC: leaf nitrogen concentration, LT: leaf
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toughness, SLA: specific leaf area, WSG: wood specific content, AGB: aboveground
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standing carbon biomass, AL: aboveground carbon litter, SOC: soil organic carbon and
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TEC: total ecosystem carbon
AGB
AL
SOC
TEC
0.64***
0.35*
0.49**
0.64***
LDMC
0.0ns
0.04ns
0.04ns
0.02ns
LNC
0.0ns
0.0ns
0.0ns
0.0ns
LT
0.05ns
0.0ns
0.06ns
0.05ns
SLA
0.0ns
0.01ns
0.05ns
0.03ns
WSG
0.57***
0.57***
0.23ns
0.45**
H
0.17ns
-0.46**
0.24ns
-0.28*
LDMC
0.03ns
0.01ns
0.13ns
0.09ns
LNC
0.21ns
0.46**
0.29*
0.33*
LT
0.17ns
0.12ns
0.37*
0.31*
SLA
0.01ns
0.07ns
0.0ns
0.01ns
WSG
-0.62***
-0.71***
-0.46**
-0.65***
Weighted means (CWM)
H
Single-trait dissimilarity
measures (FDvar)
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Multi-trait dissimilarity
measure
FDiv
-0.16ns
-0.48**
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53
54
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9
-0.6***
-0.5**
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Table S6. Multivariate analysis of trait community weighted mean (CWM) of different sites,
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and their association with carbon storage.
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Principal components analysis (PCA) of 16 sites on the basis of their trait community
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weighted means (CWM). Values in parentheses indicate the variance (%) accounted for by
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each axis. Values in the top section of the table indicate the eigenvector scores of each of
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the CWMs on the two PCA axes. The bottom section of the table shows the regression
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coefficients (R2) obtained from simple linear regression analyses between the C stocks of
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the sites and their scores on PC 1 and 2, indicated with asterisks if statistically significant.
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*: P < 0.05; **: P < 0.01; ***: P < 0.001, ns: not significant).
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PC 1
PC 2
(32.1%)
(28.9%)
Height
0.30
0.63
Leaf dry matter content
0.33
-0.31
Leaf nitrogen concentration
-0.48
0.43
Leaf toughness
0.53
-0.03
Specific leaf area
-0.45
0.08
Wood specific gravity
0.29
0.56
Aboveground standing biomass
0.14ns
0.53**
Aboveground litter
0.03ns
0.45**
Soil organic C
0.05ns
0.35*
Total ecosystem C
0.09ns
0.51**
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Eigenvector scores of CWM
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Carbon stocks (regression coefficients)
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References
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Brown, S. (1997) Estimating Biomass and Biomass Change of Tropical Forests: a Primer.
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Chave, J., Andalo, C., Brown, S., Cairns, M.A., Chambers, J.Q., Eamus, D., Fölster, H.,
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Fromard, F., Higuchi, N., Kira, T., J-P., L., Nelson, B.W., Ogawa, H., Puig, H., Riéra,
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B. & Yamakura, T. (2005) Tree allometry and improved estimation of carbon stocks
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and balance in tropical forests. Oecologia, 145, 87-99.
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Zuloaga, F.O. & Morrone, O. (1996) Catálogo de las Plantas Vasculares de la República
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Argentina I. Monographs in Systematic Botany from the Missouri Botanical Garden,
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60, 1:323.
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Zuloaga, F.O. & Morrone, O. (1999) Catálogo de las Plantas Vasculares de la República
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Argentina II. Monographs in Systematic Botany from the Missouri Botanical Garden,
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74.
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