Supplementary materials
(a)
(b)
Exclusion Cage
Go Pro camera
20cm
Screw to
attach algae
Surfboard Mount
Dive Weight
Fencing Wire
100cm
Fig S1 Standardised assay setup used to quantify herbivory on six macroalgal species. (a)
photo of an assay in place on the reef crest showing the position of the algae relative to the
video camera. Note: the exclusion cage is not attached; (b) schematic diagram of the assay
apparatus. Length of fishing line not to scale
Loffler, Bellwood and Hoey
5
-1
Algal mass removed (g 4 h ; + SE)
6
4
3
2
1
0
1
2
6
5
4
3
Site
Fig S2 Variation in macroalgal removal (g) among sites on Orpheus Island. Algal biomass
removed is the total biomass removed from the six macroalgal species
2D Stress: 0.08
4C
5S
2C
P latax spp.
6S
Other s iganids
1C
Scarus
K yphosspp.
us cineras cens
3C
4S
6C
5C
Nas o1S
unicornis
S iganus doliatus
Acanthurus s pp.
P omacanthus s exs triatus
3S
2S
Loffler, Bellwood and Hoey
Fig. S3 Non-metric multidimensional scaling analysis showing variation in herbivorous fish
assemblages among twelve locations (six sites and two habitats) around Orpheus Island. The
analysis was based on Bray-Curtis similarities of the fourth-root transformed biomass data.
Numbers 1-6 indicate sites, with ‘1’ being the northernmost site and ‘6’ being the
southernmost site. ‘C’ denotes the reef crest; ‘S’ denotes the reef slope.
A two factor ANOSIM revealed that herbivorous fish assemblages differed between locations
(ANOSIM Global R = 0.250, p = 0.001), with sites 1 and 2 differing from the remaining four
sites (Fig. S2). There was also some variation in fish assemblages between habitats (Global R
= 0.259, p = 0.015).
30
25
20
Massive Porites sp.
Turf Algae/EAM
15
6C
1C
3C
10
Factor 2: 32.56%
4C
5
4S
2S
0
Soft Coral
3S
2C
1S
-5
Acropora sp.
-10
5C
6S
Other Hard Coral
-15
Rubble
5S
-20
-25
-30
-30
-25
-20
-15
-10
-5
0
5
10
15
20
25
30
Factor 1: 39.99%
Fig S4 Principal component analysis showing variation in benthic composition across twelve
locations (six sites and two habitats) on Orpheus Island. The analysis was based on the
Loffler, Bellwood and Hoey
covariance matrix of the mean of three transects within each habitat at each site. Numbers 1-6
indicate sites, with ‘1’ being the northernmost site and ‘6’ being the southernmost site. ‘C’
denotes the reef crest; ‘S’ denotes the reef slope.
50
Algal mass removed (% 4h -1)
45
40
35
30
25
20
15
10
-30
-20
-10
0
10
20
30
Benthic PC1
Fig S5 Relationship between benthic composition and consumption of macroalgae across
twelve locations (six sites and two habitats) on Orpheus Island. The benthic composition is
represented by the scores along the first axis of the PCA. Algal biomass removed is the total
biomass removed from the six macroalgal species.
Loffler, Bellwood and Hoey
(a)
400
Kyphosus vaigiensis
Siganus doliatus
Siganus canaliculatus
Pomacanthus sexstriatus
Chaetodontoplus duboulay i
Other siganids
Naso spp.
Scarus spp.
200
-1
Sum of mass-standardised bites (4h + SE)
300
100
0
(b)
400
300
200
100
0
1
2
3
4
5
6
Site
Fig S6 Variation in the feeding rates of herbivorous fishes among 6 sites on the (a) reef crest,
and (b) reef slope of Orpheus Island. Feeding rates are mean mass standardised bites (total
bites × body mass in kg) summed across the six macroalgal species.
Loffler, Bellwood and Hoey
Table S1 Relative palatability of each species of algae used in the study
Algal species
Taxonomic
classification
Functional classification
(Steneck 1988)
Defence
Acanthophora sp.
Rhodophyta
Corticated
None
Caulerpa sp.
Chlorophyta
Corticated
Chemical
Galaxaura sp.
Rhodophyta
Calcified
Calcified,
chemical
Turbinaria sp.
Phaeophyceae
Leathery
Leathery
Laurencia sp.
Rhodophyta
Corticated
Chemical
Sargassum sp.
Phaeophyceae
Leathery
Leathery,
chemical
Palatability
References
Readily consumed in macroalgal
feeding trials
Possesses toxic terpenoid,
caulerpenyne which acts as a
deterrent to herbivory
Calcification and
allelochemicals dissuade
predation
Tough, leathery morphology,
making predation by many fish
species difficult
One of the first algae removed
when used in macroalgal
feeding trials
A dominant macroalgal species
after the occurrence of phase
shifts. Readily eaten in feeding
trials
Littler et al. 1986; Reinthal
and Macintyre 1994
Erickson et al. 2006;
Raniello et al. 2007
Paul and Hay 1986; Rasher
et al. 2011; Rasher et al.
2013
Littler et al. 1983
Reinthal and Macintyre
1994; Mantyka and
Bellwood 2007
Hughes et al. 2007; Fox
and Bellwood 2008;
Cvitanovic and Bellwood
2009
Loffler, Bellwood and Hoey
Table S2 ANOVA comparing loss of algal biomass (g) among sites, habitats and algal species.
Data was square-root transformed to improve normality and homoscedasticity.
Site
Habitat
Algal species
Site x Habitat
Site x Species
Habitat x Species
Site x Habitat x Species
F
df
p
5.34
3.21
33.94
0.99
1.52
0.52
0.80
5
1
5
5
25
5
25
< 0.001
0.075
< 0.001
0.429
0.067
0.757
0.732
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Erickson AA, Paul VJ, Van Alstyne KL, Kwiatkowski LM (2006) Palatability of macroalgae that use different types of chemical defenses. J Exp
Mar Biol Ecol 32:1883-1895
Fox RJ, Bellwood DR (2008) Remote video bioassays reveal the potential feeding impact of the rabbitfish Siganus canaliculatus (f: Siganidae)
on an inner-shelf reef of the Great Barrier Reef. Coral Reefs 27:605-615
Hughes TP, Rodrigues MJ, Bellwood DR, Ceccarelli D, Hoegh-Guldberg O, McCook L, Moltschaniwskyj N, Pratchett MS, Steneck RS, Willis
B (2007) Phase shifts, herbivory and the resilience of coral reefs to climate change. Curr Biol 17:360-365
Littler MM, Taylor, PR, Littler DS (1983) Algal resistance to herbivory on a Caribbean barrier reef. Coral Reefs 2:111-118.
Littler MM, Taylor PR, Littler DS (1986) Plant defense associations in the marine environment. Coral Reefs 5:63-71
Mantyka CS, Bellwood DR (2007) Macroalgal grazing selectivity among herbivorous coral reef fishes. Mar Ecol Prog Ser 352:177-185
Paul VJ, Hay ME (1986) Seaweed susceptibility to herbivory: chemical and morphological correlates. Mar Ecol Prog Ser 33:255-264
Raniello R, Mollo E, Lorenti M, Gavagnin M, Buia MC (2007) Phytotoxic activity of caulerpenyne from the Mediterranean invasive variety of
Caulerpa racemosa: a potential allelochemical. Biol Invasions 9:361-368
Loffler, Bellwood and Hoey
Rasher DB, Stout EP, Engel S, Kubanek J, Hay ME (2011) Macroalgal terpenes function as allelopathic agents against reef corals. Proc Natl
Acad Sci U S A 108:17726-17731
Rasher DB, Hoey AS, Hay ME (2013) Consumer diversity interacts with prey defenses to drive ecosystem function. Ecology 94:1347-1358
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Loffler, Bellwood and Hoey