Article title: Contagious seed dispersal and the spread of avian-dispersed exotic plants
Journal: Biological Invasions
Authors: N. Omar Bonilla & Elizabeth G. Pringle
Affiliations:
N. O. Bonilla, E. G. Pringle
Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI
48109
E. G. Pringle
Michigan Society of Fellows, School of Natural Resources and Environment, University of
Michigan, Ann Arbor, Michigan 48109
Corresponding author:
N. O. Bonilla. Email: omi.bonilla@gmail.com; Tel: 787-410-4614
Article type: Appendices for original research article
Appendix 1
Total seeds collected from 6 m2 of total trap sampling area beneath each of the focal native
tree species (N = 12 individuals per species) after eight weeks of sampling
Species
C. florida
Total
J. virginiana
A. rubrum
A. saccharum
29a
0
1
0
1
1
4
0
709a
0
1
0
2
1
7
1
97
2
0
6
18
0
2
0
0
0
0
1
105
20
Sassafras albidum
1
0
0
1
2
Toxicodendron radicans
0
1
1
0
2
Native taxa
Cornus florida
Cornus racemosa
Juniperus virginiana
Lindera benzoin
Parthenocissus spp.
Phytolacca americana
Vitis spp.
Total native seeds
56
6
6
1
69
162
31
11
4
208
9
1
0
0
10
12
1
0
0
13
Exotic taxa
Ampelopsis brevipendiculata
Berberis thunbergii
Celastrus orbiculatus
1
0
0
0
1
Elaeagnus umbellata
6
37
0
1
44
Lonicera maackii
0
3
0
0
3
Rosa multiflora
0
4
4
2
10
Solanum dulcamara
0
12
0
0
12
28
58
4
3
93
Total exotic seeds
Unknown
Malus spp.
Total
a
6
4
0
0
10
196
93
15
7
311
Conspecific seeds beneath C. florida and J. virginiana were not included in the analyses.
Appendix 2
Results of the selected two-way GLM comparing the relative influences of dispersal syndrome
and the local density of fleshy-fruited plants. The intercept of the model is the seed rain beneath C. florida. The
table shows all estimated coefficients and their associated p-values (see also Fig 1, Table 1)
Comparison
All tree species
All-species seed rain
Intercept
Tree sp.
J. virginiana
A. rubrum
A. saccharum
FF plant density
Tree sp. x FF plant density
J. virginiana
A. rubrum
A. saccharum
Exotic seed rain
Intercept
Tree sp.
J. virginiana
A. rubrum
A. saccharum
FF plant density
Tree sp. x FF plant density
J. virginiana
A. rubrum
A. saccharum
Tree species in forest
All-species seed rain
Intercept
Tree sp.
A. rubrum
A. saccharum
FF plant density
Tree sp. x FF plant density
A. rubrum
A. saccharum
Exotic seed rain
Intercept
Tree sp.
A. rubrum
A. saccharum
FF plant density
Tree sp. x FF plant density
A. rubrum
A. saccharum
a
Estimate
SE
2
P
-0.832
0.183
20.752
<0.0001
-1.488
-4.546
-1155.972
4.847
2.109
1.757
2.455
1.971
0.498
6.695
221680.790
6.047
0.48
<0.01
<0.0001
<0.014
-4.227
-1.795
-1130.193
1.935
1.434
~0a
4.770
1.567
>1E10a
<0.03
0.21
<0.0001
-2.144
0.341
39.445
<0.0001
5.445
-1.971
-1104.938
7.531
3.177
3.910
4.095
3.050
2.937
0.254
72816.360
6.098
<0.09
0.61
<0.0001
<0.02
-4.720
-7.604
-1086.706
2.355
5.072
~0a
4.014
2.247
>1E10a
<0.05
0.13
<0.0001
-1.733
0.227
58.169
<0.0001
-4.550
-1223.705
4.684
1.657
2.375
1.967
7.541
265417.160
5.672
<0.006
<0.0001
<0.02
-1.809
-1199.56
1.474
~0 a
1.506
>1E10 a
0.22
<0.0001
-3.333
0.498
44.867
<0.0001
-3.313
-1159.843
7.232
4.669
4.305
3.399
0.504
72588.816
4.527
0.48
<0.0001
<0.034
-8.223
-1146.943
6.086
~0a
1.826
>1E10a
0.18
<0.0001
Traps beneath A. saccharum received very few seeds (Appendix 1) and had near-zero surrounding fleshy-
fruited plant densities (Appendix 2), which generated extremely small SEs and extremely large 2 values for the
interaction effects.
Appendix 3
Total density of fruit-bearing fleshy-fruited plants per m2 in the quadrats surrounding the four
focal native tree species a
Species
C. florida
J. virginiana
A. rubrum
A. saccharum
Cornus florida
0.01
0
0.008
0
Juniperus communis
Prunus serotina
0
0.01
0.003
0.0008
0
0.0008
0
0
Rosa palustris
Sassafras albidum
Native density
0
0.002
0.0022
0.002
0
0.006
0
0.0008
0.01
0
0
0
Berberis thunbergii
0.24
0
0.08
0
Elaeagnus umbellata
0.02
0.07
0.03
0.003
Rosa multiflora
0.01
0.003
0
0
Exotic density
0.27
0.073
0.11
0.003
0
0.0008
0
0
0.292
0.0798
0.12
0.003
Native taxa
Exotic taxa
Unknown
Malus spp.
Total
a
Individuals of P. serotina and S. albidum were included automatically when individuals had a DBH > 10 cm
(see Methods).
Appendix 4
Results of the GLM examining the effect of focal native tree species, and the nested effect of
plot, on fleshy-fruited plant density in the quadrat surrounding each focal native individual. The intercept of the
model is the fleshy-fruited plant density surrounding C. florida individuals. The table shows all estimated
coefficients and their associated p-valuesa (see also Fig 2)
Comparison
Fleshy-fruited plant density
Intercept
Tree sp.
J. virginiana
A. rubrum
A. saccharum
plot[Tree sp.]
J. virginiana
A. rubrum
A. saccharum
C. florida
a
Estimate
SE
2
P
0.125
0.009
197.954
<0.0001
-0.885
-0.405
-1.118
0.130
0.130
0.130
46.246
9.685
73.737
<0.0001
<0.002
<0.0001
0.038
-0.067
-0.330
-0.316
-0.005
-0.005
-0.479
0.010
0.083
0.083
0.083
0.083
0.083
0.083
0.083
0.083
0.213
0.651
15.813
14.468
0.003
0.003
33.213
0.013
0.64
0.42
<0.0001
0.0001
0.9540
0.9540
<0.0001
0.91
Comparisons for which P < 0.05 are in bold.
Appendix 5
GLM comparisons of seed rain and plant density per m2 between the two native fleshy-fruited
focal trees, C. florida and J. virginiana a
Speciesb
Estimate
SE
2
df
P
Seed rain
A. brevipendiculata
B. thunbergii
5.382
6.087
3.040
3.269
1
1
3.14
3.50
E. umbellata
Parthenocissus spp.
-4.456
6.817
1.383
2.089
1
1
10.40
10.65
<0.08
<0.07
<0.002
0.001
P. americana
Vitis spp.
-5.382
5.471
2.205
1.628
1
1
5.96
11.30
<0.02
0.0008
Density (plants/m2)
B. thunbergii
E. umbellata
0.588
-0.112
0.125
0.036
1
1
22.18
9.73
<0.0001
<0.002
a
Comparisons for which P < 0.05 are in bold.
b
Tests for L. maackii , R. multiflora, S. dulcamara are not shown because the data were highly skewed. The
number of traps with non-zero seed rain were ≤ 3 and only beneath J. virginiana (see Fig 4).