Download influence of live coral cover and additional habitat factors on

INFLUENCE OF LIVE CORAL COVER AND ADDITIONAL
HABITAT FACTORS ON INVERTEBRATE AND FISH
COMMUNITIES IN MOOREA, FRENCH POLYNESIA
DORIANE WEILER
Integrative Biology, University of California, Berkeley, California 94720 USA
Abstract.
As the global climate changes, it is important to understand how
corresponding habitat shifts will affect organisms in many environments. Stress on coral
reefs, which foster high diversity, has the potential to cause major changes in the resident
invertebrate and fish communities. This study aimed to characterize the interactions
between invertebrates, fish, and coral reef habitat, focusing on live coral cover, habitat
heterogeneity, and coral head size. While invertebrates showed no patterns of richness
and diversity relative to live coral cover, fish richness and abundance peaked within the
>50-75% live coral range, then declined at the highest percent live coral levels. Habitat
heterogeneity was found to be the strongest factor structuring organism richness and
abundance when compared to live coral cover and coral head size. No clustering of
organisms around specific ranges of live coral cover was seen, although some evidence of
diet preferences influencing communities was present. These results demonstrated how
many habitat factors in addition to live coral can structure communities in tropical reefs,
which is important to consider for future conservation efforts.
Key words: Moorea; climate change; live coral; habitat heterogeneity; invertebrate diversity;
fish diversity; intermediate disturbance hypothesis
INTRODUCTION
Changing global climate has had
widespread
impacts
on
ecosystems
throughout the world (Walther et al. 2002). As
temperatures warm and habitats change,
organisms must either adapt or migrate to a
more suitable environment in order to survive
(Hughes 2000). Marine ecosystems are
particularly vulnerable to climate change,
especially coral reefs (Hoegh-Guldberg and
Bruno 2010, Doney et al. 2012). Rising ocean
temperatures are leading to increased coral
bleaching
and
disease,
while
ocean
acidification weakens the calcium carbonate
skeletons that provide structural integrity for
reefs (Hughes et al. 2003). In the Indo-Pacific,
which contains an estimated 75% of the
world’s coral reefs, live coral cover has
declined to an average of only 22.1% recently,
as compared to around 50% when adequate
sampling began in the 1980s (Bruno and Selig
2007). The loss of live coral is often
accompanied by a decrease in the structural
complexity and heterogeneity of the reef,
representing a dramatic change in the habitat
for associated organisms (Graham et al. 2006).
These environmental transformations are
having pervasive impacts on the organisms
present in coral reefs. Previous studies
throughout the Indo-Pacific have shown
Temae
Beach
MOOREA
N
0
1
2
FIG. 1. Site sampled in this study.
strong positive correlations between the
percent of live coral on a reef and the number
of fish species present (Bell and Galzin 1984).
Some juvenile reef fish use olfactory cues to
avoid dead coral and demonstrate stark
preferences for live coral (Coppock et al. 2013).
Additionally, Feary et al. (2008) found that
juvenile fish exhibit growth rates proportional
to the percent of live coral present, with high
live coral cover corresponding to faster
growth.
Changes
in
reef
structural
heterogeneity corresponding to a decrease in
live coral cover have also been shown to
decrease fish species richness (Luckhurst and
Luckhurst 1978). While most studies focus on
fish diversity, other studies have found a
relationship between the presence of specific
invertebrates and percent live coral cover as
well (Coles 1980).
Although decreases in diversity of some
organisms are clearly evident as the percent
live coral and habitat heterogeneity decreases
in the surrounding reef, it may be possible
that a larger shift in community structure is
occurring as new organisms occupy the niche
created by dead coral (Bruno and Selig 2007,
Done 1992). When coral dies, the remaining
carbonate structure is quickly overgrown by
algae, forming a distinct habitat (Baker et al.
2008, Fong and Paul 2010). Some species of
fish have even been found to cultivate this
algae growth and defend their territory,
creating unique communities unlike those
surrounding live coral (Hata and Kato 2006).
While currently, herbivorous fishes occupy
only 15-25% of fish species diversity and
biomass in coral reefs (Bakus 1964), this
percentage may increase in reefs dominated
by coral rubble as algae-consuming fish thrive
(Ledlie et al. 2007). Similar shifts could also
emerge
in
invertebrate
community
composition as herbivorous invertebrates such
as urchins increase in abundance with
increased algae growth (Sammarco 1982,
Ogden and Lobel 1978).
This study aimed to investigate shifts in
community structure as the percent live coral
on a coral head decreases by considering the
following questions: (1) Is there a difference in
invertebrate and fish abundance and richness
as percent live coral decreases? (2) What
habitat characteristics– including live coral
cover, habitat heterogeneity, and coral head
size– are most important in structuring the
invertebrate and fish assemblages that interact
with a coral head? (3) Are specific
assemblages of fish and invertebrates more
inclined to interact with coral heads with a
low or high percent of live coral cover? I
hypothesized that patterns of richness and
abundance will follow results of previous
studies, with higher percent live coral cover
corresponding to a more diverse community. I
expected habitat heterogeneity to be the
primary factor influencing community
composition, since more unique niches are
available for settlement. I also predicted that
two distinct communities emerge, live-coraldominated coral heads and dead-coraldominated coral heads, and expect to see more
herbivorous fish and invertebrates on deadcoral-dominated coral heads.
METHODS
Study site and coral selection
This study was conducted at Temae public
beach on the northeast side of Moorea, French
Polynesia (-17.485192, -149.764024) (Fig. 1).
Moorean coral reefs are high disturbance
communities, with cyclones, Acanthaster planci
invasions, and coral bleaching events leaving
high levels of dead coral on the reefs
(Beruman and Pratchett 2006). To guide coral
head selection, a 50 meter transect was
deployed parallel to the shoreline and 10 m
quadrats were measured on each side of the
quadrat at ten meter intervals. Appropriately
sized coral heads (between 0.4 and 0.75 m )
within the quadrats were individually labeled
using flagging tape. 69 total coral heads were
analyzed.
2
2
Habitat characteristics
Each coral head was photographed on 4
sides, separated by a 90-degree angle, and a
fifth photograph was taken from above. Total
coral area as well as the area of live coral for
each coral head was estimated using ImageJ
(Rasband 1997-2012). To calculate total percent
live cover on the entire coral head, the sum of
live coral surface area on each side of the coral
head was divided by the total surface area of
the entire coral head. Three live coral types
were found– Porites spp., Montipora spp., and
TABLE 1. Patterns of invertebrate and fish richness and abundance within each percent live
coral category. Standard deviations are in parenthesis.
Live coral
percent cover
Coral heads
found
Average invert.
richness
Average invert.
abundance
Average
fish richness
Average fish
abundance
0-25%
14
3.7 (1.28)
25.2 (10.66)
3.58 (1.5)
5 (2.37)
>25-50%
25
3.6 (1.19)
31.6 (19.70)
3.56 (1.41)
5.8 (2.25)
>50-75%
21
3.7 (1.06)
35.0 (15.80)
4.62 (1.54)
7.4 (3.14)
>75-100%
9
3.8 (0.08)
33.3 (15.31)
2.78 (1.48)
3.78 (1.86)
(a)
Invertebrate and fish surveys
In the field, each coral head was visually
surveyed for invertebrates for 3 minutes.
Organisms that could not be identified in the
field were photographed and later identified
using Humann and DeLoach (2010).
Fish surveys occurred on separate days
from invertebrate surveys and took place
between 8:30 am and 4:30 pm. The order of
surveys was generated randomly to minimize
influences of fish swimming to adjacent coral
heads. A 2 minute acclimation period allowed
for organisms to adjust to observer presence.
Acclimation was followed by a 2 minute and
30 second observation period from at least 2
meters away, then a 2 minute and 30 second
observation of organisms at a distance of less
than a meter in order to characterize and
count smaller organisms within the coral
head. Only fish that were feeding on, living
within, or hovering directly above the coral
head were counted in the survey. Unknown
fish were photographed and later identified
using available field guides (Allen et al. 2003,
Bacchet et al. 2006). Invertebrate and fish
richness and abundance were calculated using
Microsoft Excel.
Data analysis
For comparisons of percent live coral
cover, coral heads were split into 4 categories–
0-25%, >25-50%, >50-75%, and >75-100% live
coral cover. A Kruskal-Wallis test was used to
determine differences in organism richness
and abundance. If significant differences were
found, a pairwise Wilcoxon Rank Sum test
was used to determine which percent cover
categories differed from each other.
Invertebrate Richness
2
6
5
4
3
2
1
0-25%
>25-50%
>50-75%
>75-100%
Percent Live Coral
(b)
Invertebrate Abundance
Pocillopora verrucosa (Appendix A).
To estimate habitat heterogeneity on the
surface of and directly beneath each coral
head, a 50 cm grid was superimposed on the
largest coral head side using ImageJ. Each grid
intersection was counted as either dead coral,
cave, coral head overhang, live coral-Porites
spp., live coral-Montipora spp., or live coralPocillopora verrucosa.
Shannon’s index of
diversity was used to characterize habitat
heterogeneity based on these counts (Tews et
al. 2004).
Coral head size was estimated by
multiplying the top area by the height of the
coral head, which was also measured using
ImageJ.
60
40
20
0
0-25%
>25-50%
>50-75%
>75-100%
Percent Live Coral
FIG. 2. Boxplot of percent live coral cover
versus invertebrate richness (a) and abundance
(b).
The most significant habitat characteristics
structuring organism richness and abundance
were determined using general linear
modeling and stepwise variable selection,
similar to the methods used in Planes et al.
(2012). AIC scores were used to rank the
influence of percent live coral cover, habitat
heterogeneity, and coral head size. General
linear regression used on character traits
included in the strongest models to determine
significance.
Ordination analysis was performed to
determine whether unique communities
clustered on each of the four percent live coral
cover categories. Invertebrate species were
analyzed, as well as fish families. Ordination
was also used to compare percent live coral
and fish diet preferences (Appendix C) to
target whether clustering was occurring
behaviorally, rather than taxonomically. As
another method to target specific behaviors,
abundance data was standardized using the
following formula:
x =x–!
σ
new
(a)
7
6
Fish Richness
A Kruskal-Wallis test was performed on the
standardized data to compare herbivorous
and corallivorous fish abundances with
percent live coral category. A pairwise
Wilcoxon Rank Sum test was again used if
differences were found. All statistical analyses
were completed using Microsoft Excel and RStudio (R Development Core Team 2013).
5
4
3
2
RESULTS
1
Coral Cover
Live coral cover and organism richness and
abundance
Patterns of invertebrate and fish richness
and abundance across percent live coral
categories can be seen in Table 1. 14 different
invertebrates across 4 phyla were found
(Appendix B). Spearman’s rank correlation
revealed no relationship between the percent
live coral cover category and invertebrate
richness (p=0.912) or invertebrate abundance
(p=0.302) (Fig. 2).
40 fish species from 13 phyla were
recorded on the site (Appendix C).
Spearman’s
rank
correlation
revealed
significant differences between percent live
coral cover category and fish richness (p<0.05)
and abundance (p<0.01) (Fig. 3). A pairwise
Wilcoxon Rank Sum test showed richness
increased between >25-50% and >50-75% live
coral cover (p<0.05). However, fish richness
decreased between >50-75% and >75-100%
0-25%
>25-50%
>50-75%
>75-100%
Percent Live Coral
(b)
15
Fish Abundance
Three coral types were found– Porites
spp., Montipora spp., and Pocillopora verrucosa.
Montipora spp. was found on 48 coral heads
and was the most abundant coral type found,
while 41 coral heads had Porites spp. and 5
had Pocillopora verrucosa. Percent live coral
cover ranged from 0 to 100%, with an average
of 47% and standard deviation of 26%.
0
10
5
0
0-25%
>25-50%
>50-75%
>75-100%
Percent Live Coral
FIG. 3. Boxplot of percent live coral cover
versus fish richness (a) and abundance (b).
live coral cover (p<0.01). A second Wilcoxon
Rank Sum test revealed that abundance was
significantly lower at >75-100% live coral
cover compared to >25-50% (p<0.05) and >5075% (p<0.01). The category with >50-75% live
coral had the highest median fish richness and
abundance, while the category with >75-100%
live coral had the lowest median fish richness
and abundance.
TABLE 2. Akaike information criterion (AIC) values for modeling the influences of three
habitat characteristics–percent live coral, habitat heterogeneity, and coral head size– on
invertebrate and fish richness and abundance. Model 1 represents the full model with all three
characteristics, model 2 includes only habitat heterogeneity and size, and model 3 includes
habitat heterogeneity only.
Invert. richness
Invert. abundance
Fish richness
Fish abundance
Model 1
216.62
585.33
342.42
268.88
Model 2
214.78
583.81*
340.42
266.9
Model 3
212.99
NA**
338.83
265.07
*Model 2 for invertebrate richness included SDI and percent live coral, not SDI and size.
**Strongest model was produced using two independent variables, rather than only one.
Invertebrate Abundance
Invertebrate Richness
6
5
4
3
2
1
60
40
20
0
0.2
(a)
0.4
0.6
0.8
1.0
1.2
0.2
0.4
0.6
0.8
1.0
1.2
1.4
Shannon Diversity Index (Habitat Heterogeneity)
1.4
(b)
Shannon Diversity Index (Habitat Heterogeneity)
6
60
Fish Richness
Invertebrate Abundance
7
40
4
3
20
2
1
0
0
(c)
5
20%
40%
60%
Percent Live Coral
80%
0.2
100%
0.4
0.6
0.8
1.0
1.2
1.4
Shannon Diversity Index (Habitat Heterogeneity)
(d)
Fish Abundance
14
12
10
8
6
4
2
0.2
0.4
0.6
0.8
1.0
1.2
1.4
Shannon Diversity Index (Habitat Heterogeneity)
(e)
FIG. 4. Regressions for the most influential habitat characteristics structuring invertebrate
and fish richness and abundance. The only significant relationship is between habitat
heterogeneity and fish abundance (e) (p<0.05).
Integrated habitat characteristics
Community clustering and habitat preference
Akaike information criterion (AIC) values
produced using stepwise multiple regression
showed that habitat heterogeneity was the
strongest factor in determining invertebrate
richness, fish abundance, and fish richness
(Table 2). The strongest model for invertebrate
abundance
included
both
habitat
heterogeneity and the size of the coral head,
although neither had significant effects
(p=0.053, p=0.111). General linear regression
showed the effect of habitat heterogeneity was
only significant regarding fish abundance
(P<0.05), and not for invertebrate richness
(p=0.079), or fish richness (p=0.072). Graphs of
regressions can be found in Fig. 4.
Ordination showed no evidence of
discrete clustering of invertebrate species by
percent live coral cover category (Fig. 5).
Additionally, neither ordination by fish family
nor ordination by fish diet preference revealed
a unique clustering pattern based on live coral
cover (Fig. 6).
Variations in the abundance of organisms
by diet preference can be seen in Fig. 7.
Carnivores represented the largest proportion
of organisms in all groups. Corallivores were
found in all percent live coral cover categories
except for the >75-100% range. A KruskallWallis test on standardized abundance data
revealed significant differences between
and abundance decreased at the highest levels
of live coral cover.
The patterns of invertebrate distribution
seen here are unusual, considering many
invertebrates directly depend on live coral
throughout their life histories. Some
invertebrates found in this study, such as
Coralliophila violacea and Culcita novaeguineae,
consume live coral (Baums 2003, Glynn and
Krupp 1986), while others use live coral as a
settlement cue (Marsden 1987). It may be
possible that live coral cover did not affect
invertebrate richness and abundance because
invertebrates found have limited mobility and
cannot always exhibit active habitat choice
(Stella et al. 2011). In Moorea, coral reefs are
subject to high levels of disturbance that can
cause large changes in habitat over the course
of an organism’s lifespan (Trapon et al. 2011).
For sessile organisms, the original settlement
habitat may be altered as the organism
matures, eliminating evidence of habitat
preferences when settlement occurred.
Additionally, invertebrate migration from one
coral head to another presents a high
predation risk that may outweigh the benefits
of the preferred habitat (Jones et al. 1991,
Southwood 1977). The relationship between
invertebrates and live coral is highly
dependent on the life histories of individual
species, and thus may be better examined in
more specific studies that consider each
organism independently, rather than as a
combined invertebrate community.
Unlike invertebrates, fish are highly
mobile and can exhibit habitat preferences
within coral reefs (Feary et al. 2007). However,
the role of live coral in fish habitat choice has
been largely unresolved. Past studies have
provided evidence of live coral as a strong
indicator of fish richness and abundance (Bell
and Galzin 1984, Luckhurst and Luckhurst
1978), while others have found little or no
relationship between live coral cover and fish
NMDS2
1.0
Legend
0.5
0-25%
>25-50%
0.0
>50-75%
>75-100%
-0.5
-1.5
-1.0
-0.5
0.0
NMDS1
0.5
1.0
1.5
FIG. 5. Ordination with percent live coral
cover categories and invertebrate species.
percent cover categories in herbivores only
(p<0.05), although differences in corallivores
were nearly significant (p=0.068). A pairwise
Wilcoxon Rank Sum test showed herbivore
abundance was greater in the >25-50% live
coral category (p<0.05) and the >50-75%
(p<0.05) category compared to the 0-25%
category.
DISCUSSION
Live coral cover
While live coral cover is traditionally
considered one of the most important habitat
factors structuring reef communities, the
results of this study indicated that the
relationship between live coral cover and the
surrounding organisms is more complex.
Large-scale studies investigating the effects of
live coral habitat on reef communities indicate
increased fish abundance and richness (Bell
and Galzin 1984, Luckhurst and Luckhurst
1978), as well as increased invertebrate
abundance (Mortensen and Fossa 2006) with
increases in live coral cover. In contrast, this
study showed no relationship between
invertebrate richness and abundance with
changes in live coral cover, while fish richness
1.0
NMDS2
NMDS2
1.0
0.0
Legend
0-25%
0.0
>25-50%
>50-75%
>75-100%
-1.0
-1.0
-1
(a)
0
1
NMDS1
2
(b)
-1
0
1
2
NMDS1
FIG. 6. Ordination using percent live coral and fish families (a) and percent live coral and fish
diet preference (b).
abundance or richness (Roberts and Ormond
1987, Planes et al. 2012). In this study, the
lowest fish richness and abundance was found
on coral heads with the highest live coral
cover. This may be explained by the variation
in coral species composition within each live
coral cover category. At the highest level of
percent cover, Porites was the dominant
genera found on all coral heads. Porites corals
have massive structures that provide less
habitat than other coral genera and are often
avoided by fish (Pratchett et al. 2011).
Although a statistical analysis relating percent
cover of each coral species to fish richness and
abundance was not performed in this study,
future research may consider this important
factor.
The intermediate disturbance hypothesis
may also provide explanations for patterns of
fish richness and abundance seen in this
study, particularly why the highest levels of
fish richness and abundance were found at
intermediate levels of live coral cover. The
intermediate disturbance hypothesis states
that moderate levels of disturbance create the
most diverse habitats and can support more
diverse communities over time (Aronson and
Precht 1995). Without disturbance, habitats
may become homogenous and a single species
may dominate, excluding competitors and
decreasing community diversity (Petraitis et
al. 1989). At intermediate levels of live coral
cover, it is less likely that a single fish species
can dominate, thus promoting greater fish
richness and abundance.
Integrated habitat characteristics
In considering the effects of habitat on
community composition, previous research
has incorporated many coral reef habitat
characteristics, rather than focusing on a
single one, such as percent live coral cover.
For example, a study by Planes et al. (2012)
included 11 habitat descriptors and 13
geomorphologic descriptors to test the relative
importance of environmental characteristics in
structuring coral reef fish diversity. Although
this study considered only 3 habitat
characteristics– percent live coral, habitat
heterogeneity, and coral head size– patterns of
relative significance emerged for both
invertebrate and fish species. Habitat
heterogeneity was consistently the most
influential factor structuring coral head
invertebrate and fish communities.
The habitat heterogeneity hypothesis, in
combination with niche theory, provides an
0-25% Live Coral
>25-50% Live Coral
Legend
Corallivores
Herbivores
>50-75% Live Coral
>75-100% Live Coral
Omnivores
Carnivores
FIG. 7. Variation in the proportion of fish
by diet preferences per percent live coral
category.
explanation for this pattern. Together, these
concepts suggest that complex habitats
provide more unique niches for organisms,
thus promoting greater diversity (Vandermeer
1972).
The
significance
of
habitat
heterogeneity in supporting community
diversity has been studied in many
ecosystems, from deciduous forests to
farmlands (Bazzaz 1975, Weibull et al. 2000,
MacArthur and MacArthur 1961, Tews et al.
2004). In marine habitats, support for this
theory emerged in the work of Luckhurst and
Luckhurst (1978) and Sano et al. (1984), who
found that increased substrate complexity was
correlated with increased fish richness. Both
studies suggested that the observed patterns
were due to the available niche space for fish
to use as shelter in more heterogeneous
habitats.
Despite the abundance of evidence for
habitat heterogeneity supporting vertebrate
diversity, studies about the effects of habitat
heterogeneity on invertebrates are largely
neglected, according to an extensive review of
habitat heterogeneity literature by Tews et al.
(2004). Although habitat heterogeneity had the
strongest influence on invertebrate richness
and abundance in this study, the effects were
statistically insignificant. Similarly, previous
research
has
shown
that
increased
invertebrate richness could be partially
explained by habitat heterogeneity, but 45% of
the variation in richness remained inexplicable
(Idjadi and Edmunds 2006). It is also possible
that the most important habitat characteristics
determining
invertebrate
community
dynamics have yet to be studied, or that the
six coral head traits used in this particular
study were insufficient to properly capture the
heterogeneity of a coral head.
In analyzing the significance of habitat
heterogeneity for determining the diversity of
organisms, Tews et al. (2004) highlighted the
significance of “keystone structures,” specific
aspects of a habitat that provide an important
service necessary for organism survival. For
fish, holes in reefs represent a keystone
structure by providing shelter, and the
abundance of holes has been correlated with
fish abundance (Roberts 1987). Holes may also
represent
a
keystone
structure
for
invertebrates, although more research is
needed. Future studies may consider looking
at habitat factors independently, rather than as
a combined heterogeneity score, to uncover
the critical habitat structures that support
greater organism richness and abundance.
Community clustering and habitat preferences
No ecologically similar clusters were
evident for invertebrates or fish in relation to
percent live coral cover in this study,
indicating no distinct coral-determined
communities
structured
by
organism
preference. This result contrasted directly with
the original hypothesis predicting that
differences in percent live coral cover would
result in distinct communities partitioned
based on organism diets. Previous studies of
coral reefs provide evidence of habitat shifts
from live-coral-dominated to dead-coral- and
algae-dominated reefs (Done 1992), followed
by invertebrate community shifts (Coles 1980)
and fish community shifts (Munday 2004).
However, these shifts integrated temporal
aspects, rather than studying the reef at a
snapshot in time, which may explain why
distinct groupings could be seen. When fish
habitat partitioning was examined over a
shorter time interval, no microscale habitat
discrimination was evident (Sale and Dybdahl
1978). This may explain why no partitioned
groupings were apparent in this study, since
organism sampling took place over a few
months, rather than a few years.
Despite the lack of ecological clusters,
differences in fish by diet preferences could be
seen as the percent live coral varied. Again,
this did not follow predicted patterns– no
corallivores were found within the highest
percent live coral category, and algae-grazing
herbivorous fish were most abundant in
intermediate levels of live coral cover, rather
than the lowest levels where dead coral area
could provide space for abundant algae
growth. Patterns of corallivore presence may
again be affected by the dominant coral
genera found at the highest level of percent
live coral cover, Porites, as was mentioned
previously.
Corallivores
such
as
the
Chaetodintidae
(butterflyfishes)
exhibit
preferences for some coral species over others,
and Porites are often avoided (Beruman and
Pratchett 2008). Additionally, corallivore
habitat preferences may be affected more by
the availability of shelter rather than food, and
Porites coral heads lack sufficient structure for
fish to hide (Pratchett et al. 2011). Regarding
herbivore abundance and live coral cover,
previous studies have indicated that algae
growing on dead coral heads may be
inadequate to sustain herbivorous fish (Sano et
al. 1984). Since algae growth was not
measured in this study, the relationship
between dead coral, algae growth, and
herbivorous fish abundance cannot be
verified.
Conclusion
Examining how organisms partition
within their environment is a challenging
problem within the field of ecology. While this
study considered habitat aspects, it did not
consider temporal variation, interactions
between species, or any other factors that may
have significant influence on organism
richness and abundance. Additionally, the
small sample size and lack of sampling
repetition prevent the results of this study
from being generalized to the coral reef
communities as whole.
Despite these limitations, many useful
conclusions about coral reef fish and
invertebrates can be drawn from this study.
While percent live coral cover is traditionally
used as a primary indicator of coral reef health
(Coker et al. 2014), other aspects of reef
habitats, such as habitat heterogeneity, may
play a more important role in determining
macrofaunal
community
characteristics.
Additionally, organisms such as corallivores
that have been recommended as reef health
indicators may not correlate as directly with
live coral cover as was previously believed
(Hourigan et al. 1988). Overall, this study
highlights the complex interactions between
coral reef organisms and their habitat, which
may need to be considered in more specific
species-oriented investigations rather than
generalized studies.
As coral reef habitats continue to decline
due to anthropogenic influences, the effects of
habitat on fish and invertebrate richness and
abundance may play an important role in
future conservation efforts. While trajectories
of the future of coral reefs predict increased
degradation (Pandolfi et al. 2003), continued
research on reef habitat is necessary to ensure
optimized protection strategies are employed
to preserve the diverse, yet delicate ecosystem.
ACKNOWLEDGMENTS
I would like to thank my professors, Brent
Mishler, Stephanie Carlson, Jonathan Stillman,
and Vince Resh, for their guidance throughout
the project. I am also thankful for the
assistance of Jason Hwan, Seth Kauppinen,
and Jenna Judge. This project would not have
been possible without the Gump Research
Station staff. Finally, thanks to the Moorea
class of 2014 for an amazing semester.
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APPENDIX A
Corals identified in this study. All photographs taken by the author.
!
Porites spp.
Montipora spp.
!
Pocillopora verrucosa
!
APPENDIX B
Invertebrates identified in this study. Organisms not pictured include Cypraeidae 1 (identified to family
only), Diadema spp., Holothuria atra, Patellidae 1 (identified to family only). All photographs taken by the
author.
Calcinus latens
Coralliophila violacea
Culcita novaeguineae
Dendropoma maxima
Echinometra mathaei
Mitra mitra
Morula uva
Spirobranchus giganteus
Tridacna maxima
Calcinus spp.
APPENDIX C
Fish identifications used in this study. Fish species with an asterisk (*) have different characteristic traits in other life
stages (Eg. initial phase, juvenile phase, terminal phase). All photographs taken by the author.
Family
Species
Acanthuride
Convict surgeonfish, Acanthurus triostegus
Acanthuridae
Lined bristletooth, Ctenochaetus striatus
Apogonidae
Apogonidae
Characteristic
traits
Oval-shaped,
thin black vertical
bars on white
body
Diet
Source
Herbivore
Hiatt and
Strasburg
1960
Oval-shaped,
dark brown with
lighter lines on
body and small
orange spots on
head
Herbivore
Hiatt and
Strasburg
1960
Sevenstripe cardinalfish, Apogon novemfasciatus
Black and white
horizontal
stripes, two
widely separated
dorsal fins,
stripes extend
slightly onto
caudal fin,
(compare to
Chlorurus sordidus
juvenile, Apogon
nigrofasciatus)
Carnivore
Hiatt and
Strasburg
1960
Narrowstripe cardinalfish, Pristiapogon exostigma
[No image available]
White body with
one black
horizontal stripe
from mouth to
base of caudal
fin, some have
dark spot on base
of caudal fin, two
widely separated
dorsal fins
Carnivore
Allen et
al. 2003
Balistidae
Orange-lined triggerfish, Balistapus undulatus
Football-shaped
body, dark green
to brown with
orange curved
patterning, black
spot on base of
caudal fin,
anterior dorsal
fin with spine
may be
depressed, as is
pictured here
Facultative
corallivore
Cole et al.
2008
Balistidae
Picasso triggerfish, Rhinecanthus aculeatus
Football-shaped
body, tan with
lighter ventral
side, orange
stripe from
mouth to beneath
eye, blue stripes
across eyes,
central black
patch with black
bands extending
to anal fin
Facultative
corallivore
Cole et al.
2008
Blennidae
Red-spotted blenny, Blenniella chrysospilos
Elongate body,
green to tan body
with dark
banding, small
orange-red spots
on head, one
continuous
dorsal fin,
usually rest with
body curved
(compare to
Gobiidae)
Herbivore
Allen et
al. 2003
Chaetodontidae
Speckled butterflyfish, Chaetodon citrinellus
Yellow body with
many small dark
speckles, black
bar across eye,
black edge on
anal fin
Facultative
corallivore
Cole et al.
2008
Chaetodontidae
Redfin butterflyfish, Chaetodon lunulatus
Yellow body
with light
purple stripes,
black bar across
eye with dark
snout, purple
base of caudal
fin, dark red
anal fin
Obligate
corallivores
Cole et al.
2008
Chaetodontidae
Teardrop butterflyfish, Chaetodon unimaculatus
White body
with yellow
dorsal side and
yellow anal fin,
upside-down
black teardrop
in center, black
bar across eye
Facultative
corallivore
Cole et al.
2008
Chaetodontidae
Vagabond butterflyfish, Chaetodon vagabundus
White body
with grey
chevron
patterning,
black band
across eyes and
caudal fin,
yellow dorsal,
anal, and caudal
fins
Facultative
corallivore
Cole et al.
2008
Gobiidae
Eyebar goby, Gnatholepis anjerensis
White body
with brown
spots on both
body and fins,
thin bar across
eye, two distinct
dorsal fins,
usually rest with
body straight
(compare to
Blennidae)
Omnivore
Hiatt and
Strasburg
1960
Gobiidae
Goldenspot goby, Coryphopterus aureus
White or
translucent with
small orange
spots, first
dorsal fin is
triangular with
small black dash
on front
Carnivore
Allen et
al. 2003
Gobiidae
Unknown gobies 1-4
[No image available]
Carnivore
Allen et
al. 2003
Holocentridae
Smallmouth squirrelfish, Sarcocentron microstoma
[No image available]
Carnivore
Allen et
al. 2003
Labridae
Floral wrasse, Cheilinus chlorourus*
Elongate bodies,
two separate
dorsal fins, and
straight resting
position. Unique
species 1-4
identified using
unique body,
fin, and eye
markings
Red and white
striped body
with large eyes,
white tips on
dorsal fin
spines, black
spot on front of
first dorsal fin,
long white
stripe on anal
fin
Dark brown
body with white
spots in
horizontal rows,
large white
blotch on caudal
fin, red or pink
markings on
face
Carnivore
Hiatt and
Strasburg
1960
Labridae
Tripletail wrasse, Cheilinus trilobatus*
[No image available]
Dark body with
complex pink
patterning, but
with two white
bars across
caudal fin
(compare to
Cheilinus
chlorourus)
Carnivore
Hiatt and
Strasburg
1960
Labridae
Checkerboard wrasse, Halichoeres hortulanus*
White with dark
blue checkered
pattern, green
and pink
markings on
head, yellow on
dorsal and
caudal fin
Carnivore
Hiatt and
Strasburg
1960
Labridae
Threespot wrasse, Halichoeres trimaculatus*
White body,
green and
yellow face with
pink markings,
black spot on
base of caudal
fin
Carnivore
Hiatt and
Strasburg
1960
Labridae
Redshoulder wrasse,
Stethojulis bandanensis*
Grey with white
speckles on
dorsal side and
diamonds on
ventral side,
long white
horizontal stripe
from head to
caudal fin,
bright red spot
above pectoral
fin
Carnivore
Allen et
al. 2003
Labridae
Sixbar wrasse, Thalassoma hardwicke
Light green
body with six
black bars that
decrease in
length toward
posterior end,
pink markings
on face
Carnivore
Hiatt and
Strasburg
1960
Mullidae
Sidespot goatfish, Parupeneus pleurostigma
Tan elongate
body with
barbels on
mouth, black
and white patch
on side beneath
dorsal fin
Carnivore
Sorden
1982
Muraenidae
Snowflake moray, Echidna nebulosa
White with
irregular black
splotches across
entire body
Carnivore
Allen et
al. 2003
Penguipedidae
Speckled sandperch, Parapercis millipunctata
Pale with two
horizontal rows
of brown spots,
no large dark
spot on tail
(compare to
Parapercis
hexophtalma)
Carnivore
Hiatt and
Strasburg
1960
Pomacanthidae
Lemonpeel angelfish, Centropyge flavissimus
Yellow body
with neon blue
marking on
operculum and
encircling eyes
Herbivore
Hiatt and
Strasburg
1960
Pomacentridae
Surge demoiselle, Chrysiptera brownriggii
Yellow with
neon blue stripe
across dorsal
side, black spot
near back of
stripe
Omnivore
Hiatt and
Strasburg
1960
Pomacentridae
Humbug dascyllus, Dascyllus aruanus
White body
with three black
horizontal bars,
black pelvic fin,
white spot on
nose (compare
to Chrysiptera
tricincta)
Omnivore
Hiatt and
Strasburg
1960
Pomacentridae
Peacock damselfish, Pomacentrus pavo
Blue body with
light blue
markings on
face, yellow
caudal fin,
yellow tips on
dorsal and
pelvic fin
Carnivore
Hiatt and
Strasburg
1960
Pomacentridae
Dusky gregory, Stegastes nigricans
Brown body
with purple
streak below
eye, dark spot
on base of
dorsal fin, often
found farming
algae
Herbivore
Hiatt and
Strasburg
1960
Scaridae
Bullethead parrotfish (juvenile), Chlorurus sordidus*
Black and white
horizontal
stripes from
head to caudal
fin, one long
dorsal fin
(compare to
Apogon
novemfasciatus)
Herbivore
Bellwood
and
Choat
1990
Scaridae
Violet-lined parrotfish, Scarus globiceps*
Light gray with
light stripes on
belly
Herbivore
Bellwood
and
Choat
1990
Scaridae
Palenose parrotfish, Scarus psittacus*
Dark reddishbrown with
lighter mouth
Herbivore
Bellwood
and
Choat
1990
Serranidae
Peacock grouper, Cephalopholis argus
[No image available]
Brown with
light-blue spots
lined in dark
blue ring, dark
blue on caudal,
dorsal, pectoral,
and anal fins
Carnivore
Hiatt and
Strasburg
1960
Serranidae
Honeycomb grouper, Epinephelus merra
[No image available]
Light tan to
white body with
dark brown
hexagonal-like
spots
Carnivore
Hiatt and
Strasburg
1960
Serranidae
Greasy grouper, Epinephelus tauvina
Tan and brown
alternating
splotches on
body with
hexagonal
pattern
superimposed,
small brown
spots on fins
Carnivore
Allen et
al. 2003
Tetraodontidae
Blue-spotted toby, Canthigaster solandri
Dark body with
light blue spots,
light blue lines
radiating from
eyes, translucent
fins
Facultative
corallivore
Cole et al.
2008
Tetraodontidae
Whitebelly toby, Canthigaster bennetti
Tan dorsal side
separated from
white ventral
side by dark
stripe, covered
with small
orange and blue
spots, blue and
orange lines
radiate from eye
Herbivore
De Troch
et al. 1998