Supplementary material
Schuldt et al. - Woody plant phylogenetic diversity mediates bottom-up control of arthropod
biomass in species-rich forests
Methods sampling design
A funnel-shaped beating sheet (70 cm diameter) was placed at the base of the sampled tree
and arthropods were dislodged and knocked down from the tree onto the sheet by sharply
hitting the tree seven times with a beating stick. In each study plot, 25 tree and shrub saplings
were sampled along a transect running diagonally through the plot. Every two meters, the
sapling growing closest to the transect line was selected, resulting in a random selection of
tree and shrub species in each plot.
To assess the degree to which the 25 randomly selected tree and shrub saplings reflect
the differences in the community composition among plots of the overall woody plant
communities, we compared the sapling and overall plant communities with Procrustes
analysis. For this analysis, we calculated community dissimilarities among plots for sampled
saplings and overall woody plant data with nonmetric multidimensional scaling (NMDS)
analysis. Abundance data in both species sets were square root transformed and the MorisitaHorn index was used as a dissimilarity metric. NMDS were based on two-dimensional
analyses (k = 2), with stress values < 0.2 indicating appropriate fit. Procrustes analysis of the
sapling and overall plant NMDS objects (symmetric Procrustes rotation) was conducted with
the protest function in the vegan package in R (Oksanen et al. 2013), with P values estimated
based on 999 permutations.
As with most sampling methods, a few of the arthropod individuals sampled with the
beating method might belong to vagrant species not necessarily directly associated with the
plant individual they were collected from. However, as we focused on plot-level data
(arthropod data were averaged across all individuals per plot, see ‘Statistical analysis’) rather
than individual plants or plant species, and many of the abundant taxa such as lepidopteran
caterpillars are not highly mobile, the potential occurrence of such vagrants can be assumed to
have little effect on our analyses. Moreover, although interspecific differences in the precision
of these equations necessarily include a certain extent of estimation error, the equations
represent average estimates derived from a wide range of different species in a given taxon
and have been shown to adequately capture taxon-specific biomass patterns of arthropod
assemblages that are comparable in complexity to those of our study (Lampert and Tlusty
2013; Wardhaugh 2013).
Lampert A, Tlusty T (2013) Resonance-induced multimodal body-size distributions in
ecosystems. Proceedings of the National Academy of Sciences USA 110:205-209
Oksanen J, Blanchet FG, Kindt R, Legendre P, Minchin PR, O'Hara RB, Simpson GL,
Solymos P, Henry M, Stevens H, Wagner H (2013). vegan: Community Ecology
Package. R package version 2.0-10. http://CRAN.R-project.org/package=vegan. Last
accesssed 31 May 2014
Wardhaugh CW (2013) Estimation of biomass from body length and width for tropical
rainforest canopy invertebrates. Australian Journal of Entomology 52:291-29
1
Table S1. Overview of the higher taxa sampled, their functional group identity, and total
number of individuals and overall biomass per taxon for beating samples from 27 forest plots
in subtropical China
Taxon
Araneae
Opiliones
Coleoptera - Cantharidae
Coleoptera - Carabidae
Coleoptera - Chrysomeloidea
Coleoptera - Coccinelidae
Coleoptera - Curculionidea
Coleoptera - Scarabaeidae
Coleoptera - Staphylinidae
Dermaptera
Hemiptera - Aphidina
Hemiptera - Auchenorrhyncha
Hemiptera - Heteroptera
Hemiptera - Heteroptera - Reduviidae
Hemiptera - Sternorrhyncha - Other
Hymenoptera - Formicidae
Lepidoptera - larvae
Mantodea
Neuroptera
Orthoptera
Phasmatodea
Thysanoptera
Total
Functional group
Individuals
Total biomass [mg]
Predator
3732
6191
Predator
205
1379
Predator
20
684
Predator
10
215
Leaf-chewing herbivore
131
783
Predator
20
38
Leaf-chewing herbivore
111
723
Leaf-chewing herbivore
29
739
Predator
9
12
Predator
26
174
Sap-sucking herbivore
94
13
Sap-sucking herbivore
693
2512
Sap-sucking herbivore
100
508
Predator
12
273
Sap-sucking herbivore
25
16
Predator
686
399
Leaf-chewing herbivore
522
6226
Predator
8
5
Predator
9
17
Leaf-chewing herbivore
408
7065
Leaf-chewing herbivore
81
1194
Sap-sucking herbivore
19
1
6950
29167
2
Table S2. Mixed-effects models for the abundance of leaf chewing herbivores, sap-sucking herbivores, predators, and the abundance ratio of
predators to herbivores across 27 forest stands in subtropical China. Parameter estimates (with standard errors, degrees of freedom, t and P values)
are shown for the variables retained in the minimal models
Predator : Herbivore
ratio
Herbivores: Leaf chewers
Herbivores: Suckers
Fixed effectsa,b
Intercept
Time 2-1c
Time 3-1c
Elevation
Plot age
Qphyl s.e.s.
SE DF t
P
Est.
-0.52 0.04 54 -13.5 <0.001
0.10 0.04 25 2.5
0.018
Est.
-0.94
0.39
-0.87
-
AICc full modeld
AICc min.
modeld
83.4
201.8
73.9
97.5
63.6
172.7
43.4
74.7
SE
0.13
0.16
0.16
-
DF
52
52
52
-
t
-7.0
2.5
-5.4
-
Predators
P
<0.001
0.018
<0.001
-
Est.
1.05
-0.21
-0.67
0.13
0.11
-
SE
0.06
0.07
0.07
0.04
0.04
-
DF
52
52
52
24
24
-
t
17.8
-3.0
-9.4
3.1
2.6
-
P
<0.001
0.004
<0.001
0.005
0.015
-
Est.
1.05
-0.43
-0.51
0.19
0.12
-
SE
0.07
0.09
0.09
0.05
0.05
-
DF
52
52
52
24
24
-
t
15.0
-4.8
-5.7
3.8
2.5
-
P
<0.001
<0.001
<0.001
0.001
0.019
-
a
Sapling height, tree species richness and the interactions richness : Qphyl s.e.s. (standardized effect size of Qphyl), richness : plot age, time : Qphyl
s.e.s., and time : richness were included in the full models but not retained in any of the minimal models
b
Italics denote data for non-significant terms retained in the minimal models
c
Contrasts between sampling time 1 (fall) and the successive sampling times 2 and 3 (spring and summer); the intercept is the overall mean
d
Akaike information criterion (corrected for small sample sizes) of the full model (containing all predictors) and the minimal adequate model
(simplified model with lowest AICc)
3
Table S3. Mixed-effects models for the biomass and abundance of leaf chewing herbivores and the biomass ratio of predators to herbivores across
27 forest stands in subtropical China. Parameter estimates (with standard errors, degrees of freedom, t and P values) are shown for the variables
retained in the minimal models. Woody plant species richness and phylogenetic diversity (Qphyl s.e.s.) in the initial, full models were replaced by a
plot-level primary productivity measure to test whether observed plant diversity effects can be explained by plant productivity
Leaf chewers: Biomass
Fixed
effectsa,b
Leaf chewers: Abundance
Est.
SE
DF t
P
Est.
Intercept
1.41
0.15
48
9.7
<0.001
-0.53 0.04 50 -13.7
Time 2-1c
0.77
0.19
48
4.0
<0.001
-
-
-
-
3-1c
0.36
0.19
48
1.9
0.064
-
-
-
-
-
-
-
-
0.10
23
2.2
0.038
Time
Elevation
-
SE
DF t
P
-0.09 0.04 23 -2.2
-
-
-
Predator : Herbivore biomass ratio
-
Est.
SE
DF t
P
<0.001
-0.40
0.17
48
-2.4
0.020
-
-0.52
0.23
48
-2.2
0.031
-
-0.08
0.23
48
-0.3
0.736
-
-
-
-
-
-
-
-
-
-
0.034
Plot age
0.21
-
AICc full modeld
AICc min.
modeld
188.8
68.8
207.4
173.3
55.5
192.7
a
Sapling height, primary productivity and the interactions productivity : plot age, time : plot age, and time : productivity were included in the full
models but not retained in any of the minimal models
b-d
see Table S2
4
Table S4. Mixed-effects models for the functional dispersion (QBio) of the biomass of leaf chewer, sap-sucker and predator individuals per plot
across 27 forest stands in subtropical China. Parameter estimates (with standard errors, degrees of freedom, t and P values) are shown for the
variables retained in the minimal models. Woody plant species richness and phylogenetic diversity (Qphyl) in the initial, full models were replaced
by a plot-level primary productivity measure to test whether observed plant diversity effects can be explained by plant productivity
Herbivores: Leaf chewers
Fixed
effectsa,b
Est.
SE
DF
Herbivores: Sap suckers
t P
Est.
SE
DF t
Predators
P
Est.
SE
DF t
P
Intercept
-
-
-
-
-
-4.24
0.23 48 -18.5 <0.001
-3.72
0.06 48 -63.1
<0.001
Time 2-1c
-
-
-
-
-
0.78
0.32 48 2.4
0.020
-0.18
0.08 48 -2.2
0.035
3-1c
-
-
-
-
-
0.40
0.32 48 1.2
0.218
0.20
0.08 48 2.4
0.021
Time
AICc full model
114.7
AICc min. model 91.9
a-d
257.0
52.5
240.8
37.5
see Table S3
5
Table S5. Mixed-effects models for the biomass of leaf-chewing herbivores, sap-sucking herbivores, predators, and the biomass ratio of predators to
herbivores across 27 forest stands in subtropical China, based on observed Qphyl instead of standardized effect sizes of Qphyl. Parameter estimates
(with standard errors, degrees of freedom, t and P values) are shown for the variables retained in the minimal models
Herbivores: leaf chewers
Herbivores: suckers
Predators
Predator—herbivore ratio
Fixed effectsa,b
Est.
SE
DF t
P
Est.
SE
DF t
P
Est.
SE
Interceptc
1.30
0.14
50
9.4
<0.001
-0.64
0.23
52
-2.8
0.007
1.40
0.06 54
Time 2-1c
0.61
0.18
50
3.3
0.002
1.40
0.32
52
4.3
<0.001
-
-
-
-
Time 3-1c
0.26
0.18
50
1.4
0.160
-0.51
0.32
52
-1.6
0.122
-
-
-
-
Plot age
0.17
0.09
23
1.8
0.079
-
-
-
-
-
0.06 25
2.8
Qphyl
-0.09
0.14
23
-0.7 0.522
-
-
-
-
-
-
-
-
-
Plot age : Qphyl
0.41
0.09
23
4.6
<0.001
-
-
-
-
-
-
-
-
Time 2 : Qphyl
0.29
0.18
50
1.6
0.117
-
-
-
-
-
-
-
Time 3 : Qphyl
0.46
0.18
50
2.5
0.015
-
-
-
-
-
-
-
AICc full modeld
200.1
300.3
153.1
224.5
180.3
266.0
127.5
201.3
AICc min.
modeld
0.17
DF
P
Est.
SE
DF t
P
23.0 <0.001
-0.27
0.16
52
-1.7
0.102
-
-0.47
0.21
52
-2.2
0.033
-
-0.05
0.21
52
-0.2
0.822
0.05
0.11
23
0.4
0.661
-
-0.22
0.11
23
-2.0
0.061
-
-
-0.38
0.10
23
-3.7
0.001
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
t
0.009
a
Sapling height, elevation, tree species richness and the interactions richness : Qphyl, richness : plot age, time : plot age, and time : richness were
included in the full models but not retained in any of the minimal models
b
Italics denote data for non-significant terms retained in the minimal models
c
Contrasts between sampling time 1 (fall) and the successive sampling times 2 and 3 (spring and summer); if time included in the minimal model,
the intercept is the overall mean
d
Akaike information criterion (corrected for small sample sizes) of the full model (containing all predictors) and the minimal adequate model
(simplified model with lowest AICc)
6
Table S6. Mixed-effects models for the functional dispersion (QBio) of the biomass of leaf chewer, sap-sucker, and predator individuals per plot
across 27 forest stands in subtropical China, based on observed Qphyl instead of standardized effect sizes of Qphyl. Parameter estimates (with
standard errors, degrees of freedom, t and P values) are shown for the variables retained in the minimal models
Herbivores: Leaf chewers
Fixed effectsa,b
Est.
SE
Interceptc
-3.61
0.06 54
P
Predators
-63.0
<0.001
-4.25
0.21
52
-19.8 <0.001
-3.72
0.05
50
P
t
67.9 <0.001
Time 2-1c
-
-
-
-
-
0.73
0.30
52
2.4
0.019
-0.16
0.08
50
-2.1
0.038
3-1c
-
-
-
-
-
0.43
0.30
52
1.4
0.163
0.19
0.08
50
2.5
0.016
-
-
-
Time
DF t
Herbivores: Suckers
Est.
SE
DF
t
P
Est.
SE
DF
Plot age
0.06
0.06 23
1.0
0.330
-
-
-
-
-
-
Qphyl
0.14
0.06 23
2.2
0.040
-
-
-
-
-
0.06
25
1.0
Plot age : Qphyl
0.13
0.06 23
2.4
0.027
-
-
-
-
-
-
-
-
-
0.05
0.331
-
Time 2 : Qphyl
-
-
-
-
-
-
-
-
-
-
-0.18
0.08
50
-2.3
0.028
Time 3 : Qphyl
-
-
-
-
-
-
-
-
-
-
-0.04
0.08
50
-0.5
0.641
AICc full modeld
114.7
289.5
63.5
91.0
254.9
38.1
AICc min.
a-d
modeld
see Table S5
7
Fig. S1. Relationships between plot age, observed woody plant phylogenetic diversity
(Qphyl) and the biomass of a) leaf chewers, and b) the ratio of predators to herbivores across 27
forest plots in subtropical China. Note the inverted orientation of the x-axis (plot age) in b) for
better visual representation. All relationships are significant at P < 0.05 (see Table 1 for
details). All relationships significant at P < 0.05 (see Table S2 for details).
8