ELECTRONIC SUPPLEMENTARY MATERIAL
Manuscript title: A negative heterogeneity diversity relationship found in experimental
grassland communities
Authors: Antonio Gazol, Riin Tamme, Jodi N. Price, Inga Hiiesalu, Lauri Laanisto and Meelis
Pärtel
Corresponding author: Antonio Gazol
e-mail: Antonio.Gazol@ut.ee
Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, 51005 Tartu, Estonia
Online Resource 1. Figure showing the initial plant diversity in the different treatments.
Online Resource 2. Figure showing the root:shoot biomass ratio in the different
treatments.
Online Resource 3. Summary of the SEM performed to study the influence of
heterogeneity on plant diversity, relative light and biomass.
Negative Heterogeneity Diversity Relationship in experimental grassland communities
Gazol et al.
Online Resource 1. Figure showing the initial plant diversity in the different treatments.
Fig. S1 Treatment effect on plant diversity (Inverse of the Simpson´s dominance index) one
month after starting the experiment at the box level (25 x 25 cm). Values are mean ±SE for
homogeneous low fertility (Low), homogeneous medium fertility (Med), heterogeneous large
scale (HetL), heterogeneous small scale (HetS) and homogeneous high fertility (High). Dashed
lines connect treatments Low, High and two heterogeneous treatments (HetL and HetS); solid
lines connect Low, Med and High treatments. Statistics are for treatment effects
2
Negative Heterogeneity Diversity Relationship in experimental grassland communities
Gazol et al.
Online Resource 2. Figure showing the root:shoot biomass ratio in the different
treatments.
Fig. S2 Treatment effect on root:shoot biomass ratio at the box level (25 x 25 cm). Values are
mean ±SE for homogeneous low fertility (Low), homogeneous medium fertility (Med),
heterogeneous large scale (HetL), heterogeneous small scale (HetS) and homogeneous high
fertility (High). Dashed lines connect treatments Low, High and two heterogeneous treatments
(HetL and HetS); solid lines connect Low, Med and High treatments. Statistics are for treatment
effects
3
Negative Heterogeneity Diversity Relationship in experimental grassland communities
Gazol et al.
Online Resource 3. Summary of the SEM performed to study the influence of soil heterogeneity
on plant diversity, relative light and biomass.
Table 1. Coefficients associated with SEM created to study the influence of heterogeneity on
plant diversity, relative light and shoot biomass (Fig. 4). The coefficient of each pathway (raw
and standardized), its corresponding standard error (S.E.) and associated probability (P) are
shown.
coefficient
standardized S.E.
HetL  treatment
0.98
0.99
HetS  treatment
1.00
1.01
treatment  shoot biomass
12.83
shoot biomass  relative light
P
0.27
<0.01
0.60
3.58
<0.01
-.028
-0.90
0.01
<0.01
relative light (log)  shoot biomass
1.90
0.58
0.61
<0.01
treatment  plant diversity
0.19
0.09
0.41
<0.01
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Negative Heterogeneity Diversity Relationship in experimental grassland communities
Gazol et al.
Table 2. Total, direct and indirect effects of the different variables on each other according to the
SEM. Raw and standardized values are shown separated by “/”.
Total
Direct
Indirect
HetL  shoot biomass
12.55 / 0.60
-
12.55 / 0.60
HetL  relative light
-0.36 / -0.54
-
-0.36 / -0.54
HetL  plant diversity
-0.49 / -0.22
-
-0.49 / -0.22
HetS  shoot biomass
12.83 / 0.61
-
12.83 / 0.61
HetS  relative light
-0.36 / -0.55
-
-0.36 / -0.55
HetS  plant diversity
-0.50 / -0.23
-
-0.50 / -0.23
shoot diversity  relative light
-0.03 / -0.90
-0.03 / -0.90
-
shoot diversity  plant diversity
-0.05 / -0.52
-
-0.05 / -0.52
relative light  plant diversity
1.90 / 0.58
1.90 / 0.58
-
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