Table S1. The five ecological traits used to determine functional groups used in this study that are
considered the most relevant to competition in benthic communities (modified from Wahl 2009).
Body Size
S
(<1mm)
M
(1 mm - <10 mm)
L
(10 mm - <100 mm)
X
(100 mm - 1000 mm)
XX
(>1000 mm)
Growth
form
B
(bushy)
E
(encrusting)
F
(filamentous)
M
(massive)
Trophic Type
Modularity
Motility
A
(autotroph)
D
(deposit feeder)
G
(grazers)
P
(predator)
S
(suspension feeder)
C
(colonial)
S
(solitary)
A
(attached)
B
(burrowing)
C
(crawling)
D
(drifting)
S
(swimming)
Table S2. Mean cumulative abundance ± SE separated by species or taxa sampled from replicate quarts during summer 2011. Data are
separated by the four stages along the bait box pathway (Maine field, Maine distributor, Mid-Atlantic distributor, and Mid-Atlantic retailer).
For each species or taxa, abundance is separated by whether the individual was collected live or dead; abundances of dead individuals are
denoted within parentheses. Plantae and algae species or taxa are recorded as present (+) or absent (-). Bolded species indicate those that are
known successful invaders. The functional group for each species or taxa is composed of the five ecological traits considered the most
relevant to competition in benthic communities (see Table S2 for more description). Reproductive mode is denoted by D (direct
development) or indirect development (S= spawning; B= brooder; E= egg laying; A= sexual and asexual).
Taxa group
Species or Taxa
Functional
group
Reproductive mode
Amphipoda
Gammarus oceanicus
MMGSC
D
Hyale nilssoni
MMGSC
D
Orchestia grillus
MMGSC
D
Americorchestia megalophthalma
MMGSC
D
Corophium sp.
MMGSC
D
Gammarus tigrinus
MMGSC
D
Gammarus mucronatus
MMGSC
D
Gammarus palustris
MMGSC
D
Gammarus duebeni
MMGSC
D
Gammarus finmarchicus
MMGSC
D
Ampithoe valida
MMGSC
D
Gammarus sp.
MMGSC
D
Unknown Gammarid
MMGSC
D
Mytilus spp.
LMSSA
S
Mysella planulata
LMSSB
B
Lasaea adansoni
MMSSA
D
Bivalvia
Maine field
0.5 ± 0.3
(0.1 ± 0.1)
5.2 ± 3.1
(0.7 ± 0.4)
0.2 ± 0.2
(0.1 ± 0.1)
0
(0)
0.1 ± 0.1
(0)
0.3 ± 0.3
(0)
1.5 ± 1.0
(0.3 ± 0.2)
0.1 ± 0.1
(0)
2.2 ± 1.4
(0)
5.4 ± 3.2
(0)
0
(0)
0.1 ± 0.1
(0.1± 0.1)
8.9 ± 3.0
(2.0 ± 1.1)
0.7 ± 0.4
(0)
0.1 ± 0.1
(0)
0.1 ± 0.1
Maine
distributor
2.3 ± 4.2
(4.5 ± 2.1)
15.6 ± 20.3
(3.7 ± 0.8)
0.1 ± 0.3
(0.1 ± 0.0)
0.1 ± 0.2
(0.1 ± 0.0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0.0 ± 0.2
(0)
0.0 ± 0.2
(0.4 ± 0.2)
2.0 ± 3.8
(2.2 ± 0.5)
3.9 ± 4.7
(1.5 ± 0.4)
0.3 ± 0.8
(0)
0.2 ± 0.4
Mid-Atlantic
distributor
3.7 ± 7.8
(4.0 ± 1.3)
5.7 ± 10.3
(4.9 ± 1.2)
0.1 ± 0.2
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0.5 ± 0.2)
1.3 ± 2.8
(4.4 ± 1.2)
5.4 ± 7.2
(1.3 ± 0.3)
0
(0)
0
Mid-Atlantic
retailer
1.6 ± 0.8
(1.0 ± 0.5)
3.8 ± 1.4
(2.9 ± 0.9)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0.4 ± 0.2)
0.5 ± 0.2
(1.0 ± 0.5)
3.7 ± 1.0
(1.1 ± 0.6)
0.1 ± 0.1
(0)
0
Isopoda
Gastropoda
Arachnida
Crustacea
Mya arenaria
MMSSA
S
Veneridae
-
-
Jaera albifrons
MMGSC
D
Idotea baltica
MMGSC
D
Littorina saxatilis
MMGSC
D
Littorina littorea
MMGSC
S
Littorina obtusata
MMGSC
D
Littorina sp.
MMGSC
-
Melampus bidentatus
MMGSC
E
Hydrobia
MMGSC
E
Costoanachis sp.
MMGSC
-
Crepidula sp.
LMGSC
-
Skeneopsis planorbis
SMSSC
D
Boonea bisuturalis
MMGSC
E
Oribatida
SMGSC
E
Bdellidae
SMGSC
D
Halacaridae
SMGSC
D
Balanus crenatus
LMSSA
B
Unknown Cirripedia
LMSSA
B
Praunus flexuosus
MMPSS
B
Carcinus maenas
LMPSC
B
(0)
0.8 ± 0.6
(0)
0
(0)
196.9 ± 67.1
(36.7 ± 18.1)
0
(0)
90.7 ± 34.0
(0.3 ± 0.2)
15.4 ± 5.1
(0.1 ± 0.1)
23.7 ± 7.9
(0)
0.3 ± 0.2
(0)
0
(0)
1.0 ± 0.6
(0.1 ± 0.1)
0
(0)
0
(0)
0.1 ± 0.1
(0)
0
(0)
9.4 ± 5.6
(0.4 ± 0.4)
0.2 ± 0.1
(0)
84.3 ± 36.4
(0)
0.1 ± 0.1
(0)
0.1 ± 0.1
(0)
0
(0)
0.3 ± 0.1
(0.03 ± 0.03)
1.3 ± 2.3
(0.9 ± 0.3)
0
(0.03 ± 0.01)
94.9 ± 169.7
(51.4 ± 11.9)
0
(0)
8.4 ± 13.9
(1.3 ± 0.4)
2.3 ± 5.5
(0.5 ± 0.1)
2.2 ± 2.1
(0.9 ± 0.2)
0.0 ± 0.1
(0.5 ± 0.1)
0
(0)
1.0 ± 2.9
(0.4 ± 0.2)
0
(0)
0
(0.03 ± 0.03)
0.1 ± 0.4
(0.03 ± 0.03)
0.8 ± 2.3
(0.3 ± 0.1)
3.0 ± 5.0
(3.3 ± 1.3)
0.4 ± 1.0
(0.2 ± 0.1)
2.0 ± 2.5
(0.2 ± 0.1)
0
(0)
0
(0)
0
(0.03 ± 0.01)
0
(0)
0.9 ± 2.1
(0.5 ± 0.2)
0
(0)
2.8 ± 5.0
(4.9 ± 1.2)
0
(0.1 ± 0.0)
3.4 ± 6.5
(0.8 ± 0.2)
2.4 ± 3.7
(0.6 ± 0.1)
4.8 ± 4.3
(1.8 ± 0.3)
0.0 ± 0.2
(0.6 ± 0.2)
0.5 ± 1.3
(0.3 ± 0.2)
0.8 ± 2.9
(0.2 ± 0.1)
0
(0.02 ± 0.01)
0
(0)
0
(0)
1.0 ± 2.5
(0.2 ± 0.1)
0.5 ± 0.2
(0.1 ± 0.1)
0.0 ± 0.2
(0.02 ± 0.02)
0.7 ± 2.2
(0.1 ± 0.0)
0
(0)
0
(0.02 ± 0.02)
0
(0)
0
(0)
0.5 ± 0.3
(0.1 ± 0.1)
0
(0)
22.9 ± 15.4
(23.8 ± 9.5)
0
(0.05 ± 0.03)
3.9 ± 2.7
(1.0 ± 0.5)
1.3 ± 0.3
(0.2 ± 0.1)
2.5 ± 0.6
(1.3 ± 0.3)
0.1 ± 0.1
(0.2 ± 0.1)
0.1± 0.1
(0.1 ± 0.1)
0.04 ± 0.04
(0)
0
(0)
0
(0)
0
(0.04 ± 0.04)
0.2 ± 0.1
(0.1 ± 0.1)
0.2 ± 0.2
(0.5 ± 0.4)
0.1 ± 0.1
(0)
0.2 ± 0.1
(0)
0
(0)
0
(0)
0
(0)
0
Bryozoa
Alcyonidium
LMSCA
B
Flustrellidra hispida
XMSCA
B
Ostracoda
Ostracoda
SMSSC
D
Cnidaria
Metridium senile
XMSSA
A
Polychaeta
Unknown
-
-
Spionidae
MMDSB
E
Opheliidae
MMDSB
S
Sabellidae : Fabricia sp.
MMDSB
-
Phyllodocidae
MMDSB
-
Nereididae
MMDSB
-
Capitellidae
MMDSB
-
Nemertea
MMDSB
-
Platyhelminthes
Platyhelminthes
MMDSB
-
Nematoda
Nematoda
MMDSB
-
Hydrozoa
Sertulariidae A
LBSCA
A
Sertulariidae B
LBSCA
A
Chironomidae larvae
Terrestrial
-
Neuroptera
Terrestrial
-
Aranea
Terrestrial
-
Hydrophiliidae
Terrestrial
-
Cyclorrhapha : Sphaeroceridae
Terrestrial
-
Terrestrial
(0)
0
(0)
0
(0)
9.9 ± 5.3
(0)
0
(0)
0.9 ± 0.7
(0)
0.1 ± 0.1
(0)
0.1 ± 0.1
(0)
0.3 ± 0.2
(0.1 ± 0.1)
0
(0)
0.1 ± 0.1
(0)
5.1 ± 2.1
(60.7 ± 46.2)
0.1 ± 0.1
(0.1 ± 0.1)
27.9 ± 24.2
(0)
69.9 ± 46.8
(3.6 ± 2.0)
0
(0.5 ± 0.5)
0
(0.1 ± 0.1)
1.0 ± 0.7
(0)
0
(0)
0.1 ± 0.1
(0)
0
(0)
0.1 ± 0.1
(0)
0.0 ± 0.2
(0)
0.5 ± 0.3
(0)
0.1 ± 0.4
(0.05 ± 0.05)
0
(0)
0
(0.09 ± 0.06)
0.1 ± 0.2
(0)
0
(0)
0.2 ± 0.4
(0.03 ± 0.03)
0
(0.03 ± 0.03)
0.1 ± 0.3
(0)
1.3 ± 2.1
(0.1 ± 0.0)
0.3 ± 0.6
(0)
2.0 ± 5.0
(0)
1.8 ± 3.1
(0.3 ± 0.1)
0
(0)
0
(0)
0
(0.03 ± 0.03)
0.2 ± 0.5
(0)
0.1 ± 0.3
(0.03 ± 0.01)
0.0 ± 0.2
(0)
0.1 ± 0.2
(0)
0
(0)
0
(0)
0.1 ± 0.4
(0.1 ± 0.1)
0.1 ± 0.3
(0)
0.0 ± 0.1
(0.1 ± 0.1)
0
(0)
0
(0)
0.0 ± 0.1
(0.02 ± 0.02)
0
(0)
0
(0)
0.4 ± 1.0
(0.2 ± 0.0)
0.1 ± 0.4
(0)
0.1 ± 0.4
(0.02 ± 0.02)
0.6 ± 1.1
(0.1 ± 0.1)
0.0 ± 0.1
(0.1 ± 0.0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0.1 ± 0.1)
0
(0)
0
(0)
0.1 ± 0.1
(0.4 ± 0.3)
0
(0)
0
(0.1 ± 0.1)
0
(0)
0
(0)
0.3 ± 0.1
(0)
0
(0)
0
(0)
0.2 ± 0.1
(0.1 ± 0.1)
0.5 ± 0.4
(0.1 ± 0.1)
0.7 ± 0.4
(0.1 ± 0.1)
18.4 ± 16.2
(1.0 ± 0.7)
0
(0)
0
(0)
0.04 ± 0.04
(0.04 ± 0.04)
0
(0)
0
(0)
0
(0)
0.3 ± 0.2
Algae
Marsh Plants
Seagrass
Scathophagidae : Scathophaga
Terrestrial
-
Heleomyzidae
Terrestrial
-
Anthomyiidae : Fucellia
Terrestrial
-
Hymenoptera : Formicidae
Terrestrial
-
Hymenoptera : Cercopidae
Terrestrial
-
Unknown
Terrestrial
-
Gryllidae
Terrestrial
-
Figitidae : Eucoilinae : Hexacola
Terrestrial
-
Anurida maritima
MMGSC
E
Ceratopogonidae
Terrestrial
-
Collembola
Terrestrial
-
Ascophyllum nodosum
A. nodosum ecad scorpioides
Fucus vesiculosus
Fucus distichus
Fucus spiralis
Fucus spp.
Polysiphonia lanosa
Ulva sp.
Spartina alterniflora
Zostera marina
Algae
Algae
Algae
Algae
Algae
Algae
Algae
Algae
Plantae
Plantae
-
(0)
1.7 ± 1.1
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
3.1 ± 1.5
(0.1 ± 0.1)
0.2 ± 0.2
(0.1 ± 0.1)
0.3 ± 0.3
(0)
+
+
+
+
+
+
+
+
(0.3 ± 0.1)
0
(0.1 ± 0.1)
0
(0)
0
(0)
0.0 ± 0.2
(0)
0.0 ± 0.1
(0)
0.0 ± 0.1
(0.03 ± 0.03)
0.0 ± 0.2
(0)
0
(0.03 ± 0.01)
0
(0)
0
(0)
0
(0)
+
+
+
+
+
+
+
+
(0)
0
(0)
0.0 ± 0.2
(0)
0.0 ± 0.2
(0)
0
(0)
0
(0.02 ± 0.02)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
+
+
+
+
+
+
+
+
+
+
(0.04 ± 0.04)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
+
+
+
+
+
+
+
+
Table S3. Diversity measures (abundance, taxonomic richness, and functional richness) ± SE, where applicable, and observed/expected
values, calculated using species accumulation curves, separated by all taxa (algae, Plantae, marine invertebrates, and terrestrial insects) and
marine invertebrates sampled from replicate quarts during summer 2011. For each grouping, diversity measures are separated by whether the
individual was collected live or dead; data on dead individuals are denoted within parentheses. Data are separated by the four stages along the
bait box pathway (Maine field, Maine distributor, Mid-Atlantic distributor, and Mid-Atlantic retailer). Haplotype richness is also shown for
two marine snails (Littorina littorea and Littorina saxatilis) under marine invertebrates only.
Taxa group
Diversity measure
Marine
Invertebrates Only
Abundance
Maine distributor
Mid-Atlantic
distributor
Mid-Atlantic
retailer
5856
(2906)
158.3 ± 29.9
(78.5 ± 12.5)
33
(29)
36
11.0 ± 0.4
(7.4 ± 0.5)
8
(8)
9
4.2 ± 0.2
(2.7 ± 0.2)
4
1530
(1128)
34.8 ± 3.8
(25.6 ± 4.1)
26
(28)
31
7.0 ± 0.4
(7.0 ± 0.3)
8
(8)
10
3.1 ± 0.2
(2.4 ± 0.1)
3
1792
(1028)
61.8 ± 25.9
(35.5 ± 10.9)
23
(23)
27
5.8 ± 0.6
(4.3 ± 0.5)
6
(7)
6
2.6 ± 0.2
(1.8 ± 0.2)
-
Haplotype Richness
Observed
8445
(1587)
563.0 ± 97.6
(105.8 ± 49.0)
38
(17)
57
11.9 ± 0.6
(3.3 ± 0.5)
8
(4)
10
4.3 ± 0.3
(1.5 ± 0.2)
13
(Littorina saxatilis)
Expected
48
4
3
-
Average ± SE
3.5 ± 0.9
1.8 ± 0.5
2.0 ± 0.3
-
Haplotype Richness
Observed
11
-
7
-
(Littorina littorea)
Expected
28
-
11
-
Average ± SE
5.3 ± 0.5
-
3.3 ± 0.8
-
Total
8542
(1590)
5873
(2923)
1532
(1129)
1801
(1030)
Average ± SE
569.5 ± 98.0
(106.0 ± 48.9)
158.7 ± 29.9
(79.0 ± 12.5)
34.8 ± 3.8
(25.7 ± 4.1)
62.1 ± 26.1
(35.5 ± 10.9)
Observed
53
(19)
48
(35)
38
(29)
33
(25)
Total
Average ± SE
Taxonomic Richness
Observed
Expected
Average ± SE
Functional Richness
Observed
Expected
Average ± SE
All Taxa
Maine field
Abundance
(Algae, Plants, Marine
Invertebrates, and
Terrestrial Insects)
Taxonomic Richness
Expected
80
54
49
38
16.3 ± 1.0
(3.5 ± 0.5)
10
(5)
15.1 ± 0.5
(8.0 ± 0.5)
10
(9)
11.5 ± 0.4
(7.0 ± 0.3)
10
(9)
9.4 ± 0.6
(4.4 ± 0.5)
8
(8)
Expected
12
11
11
8
Average ± SE
6.0 ± 0.3
(1.7 ± 0.3)
5.7 ± 0.2
(3.1 ± 0.2)
4.2 ± 0.2
(2.4 ± 0.1)
3.7 ± 0.2
(1.9 ± 0.2)
Average ± SE
Functional Richness
Observed
Stages
Compared
MEd
vs
MAd
MEf
vs
MAd
MEf
vs
MEd
MAd
vs
MAr
MEd
vs
MAr
MEf
vs
MAr
ABUNDANCE
Mean
Dissimilarity
69.12
82.32
70.53
69.30
71.74
82.38
Jaera albifrons
20.09 (-)
FUNCTIONAL RICHNESS
Mean
Functional
Contribution
Dissimilarity
group
MMGSC
43.86 (-)
Hyale nilssoni
9.51 (-)
SMGSC
14.13 (-)
Littorina saxatilis
7.77 (-)
LMSSA
13.44 (+)
Mytilus spp.
6.45 (+)
MMDSB
13.23 (-)
Littorina obtusata
5.71 (+)
LMSSB
9.43 (-)
Jaera albifrons
21.19 (-)
MMGSC
44.68 (-)
Halacaridae
10.44 (-)
SMGSC
20.91 (-)
Littorina saxatilis
10.32 (-)
MMDSB
17.76 (-)
Nematoda
8.77 (-)
LMSSA
6.42 (+)
Littorina obtusata
5.88 (-)
SMSSC
5.63 (-)
Jaera albifrons
18.4 (-)
MMGSC
42.24 (-)
Littorina saxatilis
10.5 (-)
SMGSC
20.70 (-)
Halacaridae
9.75 (-)
MMDSB
17.49 (-)
Nematoda
7.96 (-)
SMSSC
6.38 (-)
Littorina obtusata
5.92 (-)
LMSSA
6.02 (+)
Mytilus spp.
12.37 (-)
MMGSC
37.86 (+)
Jaera albifrons
11.51 (+)
LMSSA
24.46 (-)
Littorina obtusata
10.63 (-)
MMDSB
16.45 (+)
Hyale nilssoni
9.52 (+)
LMSSB
7.27 (-)
Littorina saxatilis
8.02 (-)
SMGSC
6.64 (+)
Jaera albifrons
21.51 (-)
MMGSC
44.97 (-)
Hyale nilssoni
9.56 (-)
MMDSB
16.10 (-)
Littorina saxatilis
7.71 (-)
LMSSA
13.26 (-)
Taxa
Contribution
50.98
71.67
54.43
49.18
56.57
Mytilus spp.
6.94 (-)
SMGSC
12.59 (-)
Nematoda
6.07 (+)
LMSSB
8.82 (-)
Jaera albifrons
20.64 (-)
MMGSC
46.25 (-)
Halacaridae
10.61 (-)
SMGSC
20.45 (-)
Littorina saxatilis
10.46 (-)
MMDSB
19.08 (-)
Nematoda
9.74 (-)
SMSSC
5.61 (-)
Littorina obtusata
6.43 (-)
-
-
73.17
Table S4. SIMPER analysis for live marine invertebrates collected from replicate quarts over the four
stages of the live bait pathway during the summer of 2011. Abbreviations: MEf = Maine field sites;
MEd = Maine distributors; MAd = Mid-Atlantic distributors; MAr = Mid-Atlantic retailers. Average
dissimilarity is shown between all combinations of the stages and those taxa or functional groupings
contributing the most to the dissimilarity between stages. Values are reported as percentages and
whether their contribution to dissimilarity increased (+) or decreased (-) between the two stages.
Functional grouping codes can be found in Table S2, and the codes for each species are shown in Table
S1.