Electronic Supplemental Material
# of Sites
Longitude
Latitude
Designation
~Population per km2 reef
Island Abbreviation
Island
Archipelago
Table S1. Details of islands used in the present analysis including abbreviations for island names used in Figure 1.
Archipelago abbreviations are as follows: AMSAM: American Samoa, MAR: the Mariana Islands, HI: the Hawaiian
Islands, LI: the Line and Pacific Remote Island Areas and, PI: the Phoenix Islands.
AMSAM
Ofu & Olosega
OFU
140.28
INHABITED
-14.18
-169.62
7
AMSAM
Ta'u
TAU
100
INHABITED
-14.23
-169.45
8
AMSAM
Tutuila
TUT
1560.78
INHABITED
-14.30
-170.70
22
AMSAM
Rose
ROS
0
UNINHABITED
-14.55
-168.14
10
AMSAM
Swains
SWA
15.42
UNINHABITED
-11.06
-171.08
8
MAR
Guam
GUA
1695.56
INHABITED
13.47
144.78
9
MAR
Rota
ROT
271.32
INHABITED
14.15
145.20
5
MAR
Saipan
SAI
1098.45
INHABITED
15.18
145.76
3
MAR
Tinian
TIN
240.82
INHABITED
15.00
145.63
3
MAR
Agrigan
AGR
0
UNINHABITED
18.77
145.67
6
MAR
Aguijan
AGU
0
UNINHABITED
14.85
145.56
3
MAR
Alamagan
ALA
1.88
UNINHABITED
17.36
145.50
3
MAR
Asuncion
ASU
0
UNINHABITED
19.67
145.42
3
MAR
Guguan
GUG
0
UNINHABITED
17.31
145.85
3
MAR
Maug
MAU
0
UNINHABITED
20.02
145.22
8
MAR
Pagan
PAG
0
UNINHABITED
18.10
145.76
8
MAR
Sarigan
SAR
0
UNINHABITED
16.72
145.78
3
MAR
Uracas
URA
0
UNINHABITED
20.56
144.90
4
HI
Hawaii
HAW
767.56
INHABITED
19.57
-155.50
18
HI
Kauai
KAU
326.08
INHABITED
22.08
-159.50
11
HI
Lanai
LAN
68.96
INHABITED
20.83
-156.93
6
HI
Maui
MAI
714.73
INHABITED
20.80
-156.33
9
HI
Molokai
MOK
45.82
INHABITED
21.13
-157.03
4
HI
Niihau
NII
23.88
INHABITED
21.90
-160.17
6
HI
Oahu
OAH
2337.65
INHABITED
21.47
-157.98
11
HI
French Frigate Shoals
FFS
0
UNINHABITED
23.75
-166.15
28
HI
Gardner
GAR
0
UNINHABITED
25.02
-167.98
3
HI
Kure
KUR
0
UNINHABITED
28.42
-178.33
5
1
HI
Laysan
LAY
0
UNINHABITED
25.77
-171.74
3
HI
Lisianski
LIS
0
UNINHABITED
26.06
-173.97
7
HI
Maro
MAR
0
UNINHABITED
25.42
-170.58
5
HI
Midway
MID
0.7
UNINHABITED
28.20
-177.38
7
HI
Molokini
MOL
0
UNINHABITED
20.63
-156.50
3
HI
Necker
NEC
0
UNINHABITED
23.57
-164.70
3
HI
Pearl and Hermes
PHR
0
UNINHABITED
27.80
-175.85
33
LI
Tabuaeran
TAB
273.01
INHABITED
3.86
-159.36
11
LI
Kiritimati
KIR
152.23
INHABITED
1.88
-157.40
10
LI
Teraina
TER
203.36
INHABITED
4.68
-160.38
3
LI
Caroline
CAR
0
UNINHABITED
-9.95
-150.22
11
LI
Flint
FLI
0
UNINHABITED
-11.43
-151.80
8
LI
Jarvis
JAR
0
UNINHABITED
-0.37
-160.05
6
LI
Johnston
JOH
0
UNINHABITED
16.76
-169.52
12
LI
Kingman
KIN
0
UNINHABITED
6.38
-162.42
15
LI
Malden
MAL
0
UNINHABITED
-4.02
-154.98
14
LI
Palmyra
PAL
0.32
UNINHABITED
5.87
-162.10
20
LI
Starbuck
STA
0
UNINHABITED
-5.62
-155.93
9
LI
Vostok
VOS
0
UNINHABITED
-10.10
-152.42
6
LI
Wake
WAK
4.37
UNINHABITED
19.30
166.63
13
PI
Baker
BAK
0
UNINHABITED
0.19
-176.48
6
PI
Enderbury
END
0
UNINHABITED
-3.13
-171.08
3
PI
Howland
HOW
0
UNINHABITED
0.80
-176.63
4
PI
Kanton
KAN
0
UNINHABITED
-2.83
-171.72
6
PI
McKean
MCK
0
UNINHABITED
-3.58
-174.03
3
PI
Nikumaroro
NIK
0
UNINHABITED
-4.67
-174.52
5
PI
Orona
ORO
0
UNINHABITED
-4.50
-172.17
6
PI
Rawaki
RAW
0
UNINHABITED
-3.72
-170.72
3
2
Table S2. Results of 2 way fixed effects analysis of covariance (ANOVA) using a General Linear Model (GLM) with
latitude as a covariate on different benthic groups. Because the Phoenix Islands do not contain any inhabited
islands we treated these islands as members of the nearby Line Islands group (results are not changed if the
Phoenix Islands are left out altogether). Reef builders include both coral and CCA while fleshy algae includes turf
algae and fleshy macroalgae.
Effect
Latitude
Archipelago
Habitation
Archipelago x
Habitation
df
1
3
1
3
Coral
F
p
4.23
0.045
2.17
0.104
1.10
0.300
0.22
0.885
Macroalgae
F
P
0.93
0.339
4.84
0.005
0.80
0.375
4.82
0.005
3
Reef Builders
F
P
10.49
0.002
0.50
0.684
10.61
0.002
0.86
0.469
Fleshy Algae
F
P
3.44
0.070
3.22
0.031
6.77
0.012
0.23
0.874
Table S3. Results of the two-way multivariate permutation-based analysis of variance (PERMNAOVA) of the BrayCurtis similarity of the untransformed percent cover data of the entire benthos (among islands). Both archipelago
and habitation were treated as fixed effects and latitude was treated as a covariate. The following functional
groups were used in this analysis: hard coral, CCA, calcified invertebrates, turf algae, fleshy macroalgae, fleshy
invertebrates and non-biological substrata. A total of 99,999 permutations were used in this analysis.
Effect
Latitude
Archipelago
Habitation
Archipelago x
Habitation
df
1
4
1
MS
22735
2442.4
2920.7
Pseudo-F
53.821
5.782
6.915
P (permutation)
0.0001
0.0001
0.0002
3
574.39
1.360
0.2082
4
Table S4. Results of the Similarities Percentages (SIMPER) analysis which identifies the taxonomic functional
groups that contribute to the dissimilarity between inhabited and uninhabited islands. From this analysis turf algae
explain the greatest differences between islands with and without local human populations followed by hard coral,
CCA and finally fleshy and calcified macroalgae. These 5 groups explain 97.23% of the dissimilarity across all of the
inhabited and uninhabited islands in our data set.
Taxonomic
Group
Average Cover
on Inhabited
Islands
Average Cover
on Uninhabited
Islands
Average
Dissimilarity
Percent
Contribution to
Dissimilarity
Turf Algae
Hard Coral
CCA
Fleshy
Macroalgae
Calcified
Macroalgae
56.04
14.87
12.4
3.24
37.32
23.89
20.48
6.27
9.7
6.66
5.14
3.26
34.10
23.40
18.05
11.44
Cumulative
Percent
Contribution to
Dissimilarity
34.10
57.49
75.54
86.98
4.54
4.76
2.92
10.25
97.23
5
Table S5. Pearson’s correlation coefficients and associated p values between all benthic functional groups analyzed
in this study across 56 islands in the central Pacific. Significant correlations at alpha < 0.05 are indicated in bold and
significant correlations with a Bonferroni correction for multiple tests (p<0.002) are indicated in bold and gray
shading.
CCA
Calcified
Macroalgae
Calcified
Invertebrate
Turf Algae
Fleshy
Macroalgae
Fleshy
Invertebrate
Coral
CCA
R=0.162,
p=0.232
R=0.094,
p=0.492
R=0.040,
p=0.773
R=-0.708,
p<0.001
-0.128,
0.348
-0.053,
0.697
R=0.206,
p=0.128
R=0.204,
p=0.132
R=-0.686,
p<0.001
R=0.166,
p=0.220
R=-0.054,
p=0.690
Calcified
Macroalgae
Calcified
Invertebrate
Turf
Algae
Fleshy
Macroalgae
R=-0.027,
p=0.845
R=-0.389,
p=0.003
R=-0.032,
p=0.815
R=0.333,
p=0.012
R=-0.126,
p=0.354
R=-0.070,
p=0.608
R=-0.061,
p=0.6556
R=-0.245,
p=0.069
R=-0.121,
p=0.374
R=0.118,
p=0.388
6
Figure S1. Relationships between the abundance of A) coral, B) macroalgae, C) active reef builders (corals and
crustose coralline algae) and, D) fleshy turf and macroalgae with latitude. Each point represents the mean of an
island. Circles with black fills represent uninhabited islands while circles without black fills represent islands that
are inhabited. Colors correspond to the archipelago specified in the legend and in Figure 1.
7
Figure S2. Mean percent cover of all benthic functional groups used in this analysis by island, archipelago and
habitation (gray shaded islands are inhabited while non-shaded islands are uninhabited). The lighter pastel colored
functional groups are all of the calcifying organisms while the darker colored functional groups are all fleshy, noncalcified taxa. The purple bar indicates non-living material such as sand and basalt. Samoa only includes islands in
American Samoa and the Line Islands include the US islands and atolls in the Pacific Remote Island Area (PRIA)
Marine National Monument of Wake and Johnston which are nearby but not technically part of any archipelago as
well as the Kiribati islands and atolls.
8