Thailand Quantification of Macrofauna
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Transcript of Thailand Quantification of Macrofauna
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Quantification of variability in marcofauna
of pre-tsunami sedimentary tropical shores
of SW Thailand
By James Fay
MSci Marine Biology
2012
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Abstract
This report aimed to assess the variability of macrofaunal species at the sites: LSon = Laem
Son; TND = Thung Nang Dam; KRa = Ko Ra; Kb = Krabi. Off of the coast of SW Thailand
where it then quantified this variability by analysing the data using MDS plots, CLUSTER
plots of abundances of the macrofauna at each station first with singleton results and then
without singleton results. This showed that the removal of singletons decreased the similarity
between the sites most likely due to the removal of a species that was common at another site.
It also showed that from the MDS plots the site Kb was particularly dissimilar to the other
three sites TND, LSon and KRa. The results then looked at the feeding mechanisms of the
species to find a small variation between the sites which was attributed to each site having a
different habitat. This was also seen in the last result which showed the sites were variable
with regards to having vegetation present as only some sites had vegetation present. This was
identified to be sea grass. However further analysis showed that the habitats varied even more
due to physical factors where internal waves were present and the possibility of patchiness of
the vegetation. Furthermore different levels of nutrient inputs influenced the productivity of
each site causing more variation. These contributing factors lead to unique habitats at each
site which was found to be the main cause in the variation as the habitat influences the
species present at the site.
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Introduction
The importance of quantifying variability of an ecological system is an important study
which is needed to understand processes which are occurring that cause various patterns to
arise. By quantifying this variability it is possible to construct models which can predict
patterns and responses of various anthropogenic and natural inputs to a system. From these
models it is also therefore possible to form new hypotheses (Ysebaert & Herman, 2002). By
quantifying variations it is possible to construct food webs by looking at the interactions
between different sites. This also makes it possible to implement management protocols in
order to maintain and sustain ecosystemsbiodiversitys which are of growing interest with
the potential to discover new patterns (Landres et al. 1999 & Barrio Frojan et al. 2005).
Within this study the area to be studied is a series of sites located off of the coast of SW-
Thailand within the Andaman Sea shown by (figure 1). The reason for choosing this site for
quantifying variability is because there is minimal previous work been carried out on this area
before (Barrio Frojan et al. 2006). Where understanding the variability of a system is
important in understanding its processes and makes it a scientifically important site (Ysebaert
& Herman 2002). Furthermore it is an important location for this study to be carried out
seeing as it is an important fishing ground and undergoes a biannual monsoon season creating
a unique ecosystem through large seasonal variations (Buranapratheprat et al. 2002 &
Nielsen et al. 2004). Other reasons for studying the SW Thailand coast is due to its strong
tidal actions which makes suspended particulate matter available causing high productivity
and a site of biological interest (Umezawa et al. 2009).
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Figure 1. Map to show study area where data was collected at the stations, LSon, KRa, TND
and Kb where LSon = Laem Son; TND = Thung Nang Dam; KRa = Ko Ra; Kb = Krabi
(Barrio Frojan et al. 2006).
From (figure 1) you can see the locations of the sites where the data was collected the sites
are spread over 200km of coastline and are geographically separated as a result of this. Along
the coastline mangroves and sea grass are present which provide sediment stability and help
dampen the effect of tsunamis. All of the sites within the study have a semi-diurnal tidal
cycle (Barrio Frojan et al. 2006).
The reason for quantifying macrofauna off of the coast of Thailand is because they are a very
important part of marine food webs. Where monitoring them is important for monitoring a
system (Ysebaert & Herman, 2002). Macrofauna also make good indicator species of changes
to a system due to their constant presence within the system due to various macrofaunal
species having sedentary lifestyles. Therefore by studying the macrofauna of Thailand it is a
good indicator towards changes occurring such as pollution and will also give an idea what
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will be happening to the ecosystem as a whole which will aid in management (Ababio et al.
1999). Macrofauna are also have important ecological effects on the environment through
their sediment interactions due to some species having burrowing lifestyles as burrows
increase microbial productivity (Kristensen and Kostka 2004). Furthermore macrofauna can
also be classified into bio-turbators and bio-stabilisers where they either weaken or strengthen
the sediment respectively via burrowing or foraging motions, this has a major impact
ecologically as it influences the habitat they live in (Volkenborn et al. 2009). For these
reasons this study will concentrate on the variability of macrofauna as they are of important
ecological significance.
The aims of this study is therefore to look at the variability of macrofaunal species between
the sites Kb, LSon, KRa and TND with an emphasis on polychaete species where it is then to
identify any variabilitys and differences found between these sites using statistical analysis.
The aim is to then quantify the variability in order to understand why these sites differ from
each other in order to understand any patterns that may occur. To hypothesis the sites will be
varied from one another as they are located within different areas and will have different
processes acting upon them. On the other hand the stations within the sites will be less varied
as they will have the same processes acting upon them.
Methods
The data was collected from the methods of (Barrio Frojan et al. 2006).
This data was then analysed using Primer where MDS plots and CLUSTER plots were
constructed to look at the similarities between each station of the study area. The data was
also re-analysed after removing species that only appeared once at a station so the more
abundant species could be compared more closely. Furthermore as polychaetes were the
primary subject of the study and also most abundantly found the results were also analysed
without the other species found so the stations variability can be compared with respect to
just polychaetes. Whilst constructing graphs for where singleton species had been removed
for polychaete and crustacean species the stress level of the graphs were too high and
therefore not reliable enough to be used as a result. In addition to looking at the variability of
species found. The feeding mechanisms of each species found were identified and compared
using MDS and CLUSTER plots and a stacked bar graph to look at breakdown of feeding
types at each station which would reveal variations attributed to feeding. Lastly the seabed
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habitat was identified for each station and compared comparatively within a table in order to
identify variation at a habitat level.
Results
After analysing the results collected off the coast of Thailand the graphs showed the
following variations between the different sites of macrofaunal species:
Figure 2. MDS plot of polychaete and crustacean species abundances at each site including
singleton species with similarity rings in (%) to show how similar each site are from each
other.
From (figure 2) the variation between different sites is very high as they are only 24% similar
and there is a larger variation between Kb and the other sites TND, LSon and KRa, therefore
a larger difference between them. However the stations at each site were more closely related
as they have a higher similarity shown by the 40% similarity ring. This shows that there is
still a high amount of variation within each site of the study area. As a result when
quantifying the variation there are site specific and station specific variables that need to be
explained.
Speci es_Ab undance
Transform: Log(X+1)
Resemblance: S17 Bray Curtis similarity
SiteTND(N)
TND(S)
KRa(N)
KRa(S)LSon1
LSon2
Kb1a
Kb1b
Kb2a
Kb2b
Similarity24
40
60
TND(N)_A3TND(N)_B1
TND(N)_B3TND(N)_B4
TND(N)_C1
TND(N)_C3
TND(S)_A1
TND(S)_A2
TND(S)_B1
TND(S)_B3TND(S)_B4
TND(S)_C2
KRa(N)_A1
KRa(N)_A3
KRa(N)_B1KRa(N)_C1
KRa(N)_C3KRa(N)_C4
KRa(S)_A2KRa(S)_A3KRa(S)_B2
KRa(S)_B3
KRa(S)_C1KRa(S)_C4
LSon1_A4
LSon1_B2LSon1)_B3
LSon1_C1
LSon1_C3
LSon1_C4
LSon2_A1
LSon2_B1LSon2_B4
LSon2_C1
LSon2_C2
LSon2_C3
Kb1a_A1
Kb1a_A2Kb1a_B1
Kb1a_B2
Kb1a_C1Kb1a_C2
Kb1b_A3
Kb1b_A4Kb1b_B3
Kb1b_B4
Kb1b_C3
Kb1b_C4
Kb2a_A1
Kb2a_A2
Kb2a_B1
Kb2a_B2Kb2a_C1
Kb2a_C2Kb2b_A3
Kb2b_A4
Kb2b_B3
Kb2b_B4
Kb2b_C3
Kb2b_C4
2D Stress: 0.24
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Figure 3. MDS plot of just polychaetes at each station including singleton species with
similarity rings in (%) to show how similar each site are from each other.
Within (figure 3) where crustacean species have been removed when comparing to (figure 2)
it shows a similar pattern of variation between sites at 24% similarity and also between
stations at 40% similarity. However it has also increased similarity between some stations for
example station LSon2_A1 is now more similar to its surrounding stations, yet it has also
decreased similarity between other LSon stations. This indicates that there is a strong
crustacean presence at LSon which is causing variation between the sites and stations.
Speci es_Ab undance
Transform: Log(X+1)
Resemblance: S17 Bray Curtis similarity
SiteTND(N)
TND(S)
KRa(N)KRa(S)
LSon1
LSon2
Kb1a
Kb1b
Kb2a
Kb2b
Similarity24
40
60
TND(N)_A3TND(N)_B1
TND(N)_B3TND(N)_B4
TND(N)_C1
TND(N)_C3
TND(S)_A1
TND(S)_A2
TND(S)_B1
TND(S)_B3TND(S)_B4
TND(S)_C2
KRa(N)_A1
KRa(N)_A3
KRa(N)_B1
KRa(N)_C1
KRa(N)_C3KRa(N)_C4
KRa(S)_A2KRa(S)_A3KRa(S)_B2
KRa(S)_B3
KRa(S)_C1KRa(S)_C4
LSon1_A4
LSon1_B2LSon1)_B3
LSon1_C1
LSon1_C3LSon1_C4
LSon2_A1
LSon2_B1LSon2_B4
LSon2_C1
LSon2_C2
LSon2_C3
Kb1a_A1
Kb1a_A2
Kb1a_B1
Kb1a_B2Kb1a_C1
Kb1a_C2
Kb1b_A3
Kb1b_A4
Kb1b_B3
Kb1b_B4
Kb1b_C3
Kb1b_C4
Kb2a_A1
Kb2a_A2Kb2a_B1
Kb2a_B2Kb2a_C1
Kb2a_C2
Kb2b_A3Kb2b_A4
Kb2b_B3
Kb2b_B4
Kb2b_C3
Kb2b_C4
2D Stress: 0.23
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Figure 5. CLUSTER plot of site total abundances of polychaetes with singleton species with
a 50% slice.
The similarity between each site shown in (figure 5) also shows the differences between the
Northern, Central and Southern sites as shown in (figure 4). The TND and KRa Central sites
are more closely related together, the Southern Krabi sites are more closely related to each
other and the Northern LSon sites. From the above figures it shows that there are clear site
specific variables causing variation.
Adundance
Group average
Kb1b
Kb1a
Kb2a
Kb2b
KRa(N)
KRa(S)
KRa
TND(N)
TND(S)
TND
LSon2
LSon1
Samples
100 80 60 40 20
Similarity
Transform: Log(X+1)
Resemblance: S17 Bray Curtis similarity
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Figure 6. MDS plot of polychaete abundances at each station without singleton species with
similarity rings in (%) to show how similar each site are from each other.
By removing species that only appeared once at a site or station the species that form themajority of a sites population can be compared and as a result can be more closely compared.
from (figure 6) looking at polychaete species by removing the singletons it has decreased the
similarity between sites as the Northern, Central and Southern sites have decreased similarity
between each other. Furthermore comparing between stations at each site their similarity has
also decreased. This shows that the addition of singleton species causes less variation
between sites and stations, but also that the majority of the population present at each site is
more varied between each other which by removing the singleton results have revealed this
result.
AbundanceTransform: Log(X+1)
Resemblance: S17 Bray Curtis similarity
Site
TND(N)
TND(S)
KRa(N)
KRa(S)
LSon1
LSon2
Krabi 1a
Krabi 1b
Krabi 2a
Krabi 2b
Similarity
20
50
2D Stress: 0.22
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Figure 7. The percentage of each feeding type found at each site shown comparatively
against other stations (Fauchald & Jumars, 1979).
Analysing the feeding type (figure 7) shows that there is some variation with feeding type at
each site as the Central cites TND and KRa have a higher percentage of deposit feeders than
the other stations. However they vary from each other as TND has a larger percentage of
carnivores than KRa. Yet KRa has a higher percentage of surface deposit feeders than TND.
When looking at the LSon Northern sites has the largest percentage of carnivores present and
has low percentages of other feeding type species. It also has a small percentage of filter
feeders present as well. And lastly the Krabi Southern sites have a consistent carnivore
percentage but have a high percentage of surface deposit feeders and deposit feeders. From
these variations in feeding type between each site this could explain some of the variation
between the sites. However as they are still very similar as shown by (figure 8) it cannot
account for all of the variation and there are other factors causing the variation between the
sites.
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
TND(N) TND(S) TND KRa(N) KRa(S) KRa LSon2 LSon1 Kb1a Kb1b Kb2a Kb2b
surface deposit feeder carnivore deposit feeder filter feeder carrion feeder
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Figure 8. MDS plot to show how similar the variation in feeding types between stations is
using similarity rings in (%) to show how similar each site are from each other (Fauchald &
Jumars, 1979).
Within (figure 8) it shows the similarity of each site with regards to each feeding type found
at each site for polychaete species which shows that the sites are very similar with similarity
between all sites above 80% as shown by (figure 9). It also shows there is still a larger
difference between the Southern Krabi sites and the other Northern LSon and Central TND
and KRa sites. This could account for some of the large species variations between Kb and
the other three sites TND, KRa and LSon.
Abundance
Transform: Log(X+1)
Resemblance: S17 Bray Curtis similarity
TND(N)
TND(S)
TND
KRa(N)KRa(S)
KRa
LSon2
LSon1
Kb1a
Kb1b
Kb2a
Kb2b
Similarity85
9095
TND(N)
TND(S)
TNDKRa(N)
KRa(S)
KRa
LSon2
LSon1
Kb1a
Kb1b
Kb2a
Kb2b
2D Stress: 0.11
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Figure 9. CLUSTER plot showing the similarity of different feeding types at each station
(Fauchald & Jumars, 1979).
From (figure 9) it further reinforces the high similarity shown by (figure 8) and that there is a
site variation with regards to feeding type which could account for some of the variation of
the study area of Thailand. It also shows that the variation between the Northern, Central,Southern site is the greatest. Also as the similarity of the feeding types is very high it means
that the feeding type does not explain all of the variation between the sites and is therefore
only a contributing factor.
Abundance
Group average
Kb1a
Kb1b
Kb2b
TND(N)
TND(S)
TND
KRa(S)
Kb2a
LSon2
LSon1
KRa(N)
KRa
Samples
100 95 90 85 80
Similarity
Transform: Log(X+1)
Resemblance: S17 Bray Curtis similarity
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Station Habitat Sand (%)
TND (N) Vegetated 71
TND (S) Vegetated 62
KRa (N) Non-Vegetated 60KRa (S) Non-Vegetated 64
LSon1 Non-Vegetated 55
LSon2 Vegetated 41
Kb1a Vegetated 60
Kb1b Non-Vegetated 93
Kb2a Vegetated 60
Kb2b Non-Vegetated 56Table 1. Habitat state and sand coverage at each station (Barrio Frojan et al. 2006).
Within (Table 1) it shows what type of habitat is present at each site and the sand coverage of
the seabed. From which you can see that the habitat state is variable as Vegetative state is
regardless of sand coverage for example KRa (N) is not vegetated but Kb2a is vegetated
where both have a sand coverage of 60%. However as the habitat state is variable between
sites this could explain some variation in species found. The habitat state variation is most
likely due to some other variable acting upon the system. Also when comparing the
vegetative state against feeding type. Sites that have vegetation have a larger percentage of
the more dominant feeding type and seem to account for a larger percentage of the feeding
types present at a station.
To summarise the results there is a large difference between the sites particularly between Kb
and the other three sites TND, KRa and LSon. Also by removing the crustaceans it decreasesthe variation as and the sites become more similar. But removing the singletons increases
variation between the sites. The stations within each site are also more similar to each other
than compared to other station from other sites. There is also a variation of feeding type
between the sites but are still very similar. And lastly the vegetative state varies from site to
site with different coverages of sand. Furthermore the most common species of polychaetes
to be found are from the families: Nereididae, Spionidae, Capitellidae and Paraonidae (Barrio
Frojan et al. 2006).
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Discussion
Analysing the results there are many different potential causes to the large variation between
each site seen within the results which could be attributed to physical, chemical or biological
factors. Furthermore there may be some anthropogenic influences that could cause these
variations. In addition interactions between all these may produce further variations.
Firstly possible variations that may be quantified by physical processes could be the presence
of solitons caused when the waves hit the Nicobar Islands causing internal waves which
allow the potential for high productivity. This causes turbulence and shear which has a
potential of mixing and exposure to strong wave action which is documented on nearby
beaches of Phuket Island (Dexter, 1996). However due being on the other side of Phuket
island Krabi is sheltered from this and therefore is not exposed to these unlike LSon, TND
and KRa. This therefore allows for some potential variation between these stations.
Furthermore LSon is more exposed as it is not as sheltered as TND or KRa which are more
sheltered by the island Ko Phra Thong (Nielsen et al. 2004). Furthermore Krabi is within a
mangrove area which reduces water currents making it a sheltered area which is also similar
for TND which has allowed the growth of sea grass and vegetation which may quantify for
variation between the sites (Chansang and Poovachiranon 1994 & Cochard et al. 2008). Due
to the sheltered nature of Krabi compared to the other stations which are more exposed via
the internal waves this has implications towards larval dispersal as the larvae will not disperse
as well compared to the other stations and therefore species at Krabi may be different
compared to the other stations as they become more isolated (Beu and Kitamura, 1998). This
could explain why the other sites are more similar compared to Krabi.
Chemical processes could also quantify some of the variation between the sites as Thailand
has a large amount of pig, poultry farm, fish ponds and paddy fields which causes a high
amount of nutrients to run-off into the estuaries of Thailand which pollute the surrounding
areas (Buranapratheprat et al. 2002). Where also industrialisation and use of pesticides has
caused an increase in mercury contamination within the Andaman sea (Cheevaporn and
Menasveta, 2003). Through different levels of nutrient inputs from different estuaries can
cause variation between the sites through different levels of productivity. The different levels
of nutrients available to the sites are also different if vegetation is present as the bioavailable
carbon is much higher where vegetation is present compared to sites where no vegetation is
present. As a result of sites with vegetation present more nutrients are available and therefore
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have a higher productivity allowing a larger carrying capacity for that site which will allow
more species to exist and as a result have a higher diversity. This higher diversity will cause
variation between the sites and could be a possible reason for the large difference seen
between the sites (Duarte et al. 2005). Furthermore because Krabi is more sheltered it could
cause eutrophication through high residence times and poor tidal flushing (Cheevaporn and
Menasveta, 2003). In addition to that there is also a large amount of sewage discharge from
Phuket which would fuel eutrophication (Reopanichkul et al. 2010). In addition due to the
other sites being more exposed to wave action and in a tsunami vulnerable area they are
prone to backwash where sediment is transported via tsunamis and causes large amounts of
Suspended particulate matter to become available (Sugawara et al. 2009).
In addition potential biological influences that could cause the large variations observed
could be due to different predators present at different site which would cause different food
webs to emerge and as a result cause different species to occur at different sites causing
variation between the sites. This would arise through a variation of habitat caused by the
above physical and chemical factors which cause different habitats to occur. For example the
sheltered nature of Krabi surrounded by mangroves and some of the stations vegetated by sea
grass provide a more complex habitat allowing prey items to hide more efficiently as a result
predators adapted to hunting in vegetation would arise here. This would also be similar atTND but because it is more exposed a different predator adapted to hunting in more exposed
conditions would arise here. Then compared to the sites like LSon and KRa which are
exposed and low in vegetation predators adapted to catching prey items that dont have the
option of hiding in vegetation would be found here as the habitat complexity would be lower.
Through different levels of habitat complexity i.e. vegetated with sea grasses or non-
vegetated will cause different predators which causes variations between the sites (Beukers &
Jones, 1997).
In addition the variation in habitat makes different niche environments available where
different species will arise suited to their surrounding environment for example the presence
of vegetation at the sites which is known to be sea grass (Barrio Frojan et al. 2006). The
presence of sea grass provides a three dimensional habitat for macrofauna as they can feed
amongst the sea grass and not just on the sediment as a result it provides a larger habitable
environment for species to live in which will increase the diversity of the site containing sea
grass. On the other hand the sites without sea grass will be restricted to feeding on the
sediment and therefore be less diverse as the habitable environment is less without sea grass
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(Ansari etal. 1991). Which as shown within the results there are sites with sea grass and
without sea grass present. Through the presence of different habitats this therefore causes
variation between the sites. Furthermore from the seabed coverage of sand all sites had sand
present which would indicate that the sea grass is most likely patchy which could explain the
variation between the stations of sites that contained sea grass (Wiens, 1997). Furthermore
patchiness also creates two habitats within the same area which would increase diversity
further and allow new species that can utilise both the sea grass habitat and the exposed
seabed environment which would cause greater variation between the sites depending on the
patchiness of sea grass (Wiens, 1997). This could account for the differences between the
Northern, Central and Southern areas. Where the Northern site is non-vegetated and exposed.
The Central sites are both vegetated and non-vegetated and semi-exposed and the Southern
Krabi site is both non-vegetated and vegetated but sheltered. With different habitats present at
each location different species will occur and cause variation between the sites and could be
the reason why the sites are so different from each other.
One potential cause of variation between the sites could be due to the presence or absence of
mangroves at a station as it is documented that mangroves are along the coast line (Barrio
Frojan et al. 2006) which provide a different habitat for species to thrive in. however near
Ranong the mangroves have been commercially exploited which is near the site LSon whichis an exposed area. The removal of the mangroves from this area may have caused variation
of LSon from the other sites by removing a habitat for prey items to hide amongst. This could
explain why LSon has a large proportion of carnivores present compared to the other sites
(Macintosh et al. 2002).
Another biological influence that could be a contributing factor towards the the large
variation between the sites is the feeding type of the species found at the sites. Due to the
different habitats different food sources are available and therefore different feeding methods
are used in order to obtain that food which causes variation as shown in the results. These
different feeding mechanisms arise as a result of the habitats being different which as a result
mean different species are present (Fauchald and Jumars, 1979 & Gutierrez and Iribarne,
2004).
Looking at the results section other potential reasons for the large variability between stations
could be due to the presence of crustaceans as well as polychaetes. As within the singleton
section where crustaceans have been added the sites become more dissimilar from each other
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but when removed become more similar to each other. This shows that basing the similarity
of a site based on just polychaetes is not enough to quantify the full extent of variability at a
site as when adding other classes of species the variation increases between the sites as
interactions between different species becomes more noticeable as species that are usually
associated with another species will occur near them. After taking into account all the species
that appear at each site there will be even more variation as it cascades through different
trophic levels (Southwood, 1977).
When the singleton species were removed it showed that the sites became more dissimilar
indicating that the singletons reduced variability. This is most likely due to the singletons
being present at more than one site and therefore by removing them it removes a common
factor between sites and therefore decreasing similarity. Also it was documented from
previous studies using the same dataset that only one species occurred at all stations and that
33% of the species found only occurred at one site therefore by removing singletons it would
mean that there would not be the same species present at every station and unlikely that 1
species would appear at multiple stations as a result removing singletons causes more
variability between the sites (Barrio Frojan et al. 2006). The possibility why the removal of a
singleton species may decrease similarity is because if at one site a species is abundant but at
another site it is a singleton, the presence of that singleton makes it more similar to the sitewhere the same species is abundant. By removing it removes the link between the sites and
makes them more dissimilar. On the other hand it would improve similarity if rare species
were removed that only occurred at one site as it would remove a difference between sites.
However as similarity decreased it would imply that singletons found and removed were
most likely present in more abundance at other sites rather than being rare. This has most
likely occurred due to larval dispersal where a few larvae have left the Krabi site and become
singletons at other sites or vice versa where larvae have been carried into Krabi this would
explain how you could have an abundant species at one site and then a singleton species at
another site (Beu & Kitamura, 1998).
Another source of potential variability is the genetics of species at each site. Where Krabi is
more isolated there is the potential for limitation in the gene pool as conditions are more
stable due to being sheltered. This would impact the site by reducing the fitness of individuals
and whilst having a large species diversity there may be a low genetic diversity as a result of
low larval dispersion. As a result at the other stations there may be smaller species diversity
due to more exposed conditions but a greater genetic diversity and therefore a higher
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individual fitness due to a greater larval dispersal potential (Bell and Okamura, 2005 &
Bulleri and Chapman, 2010). However this has not been tested and would be ideal for future
study in order to test this as a hypothesis. Another potential topic for future study would be to
look at the larval dispersal from each site as this data would reinforce or disprove the gene
pool limitation hypothesis. Furthermore it would also further investigate the presence of
singletons and their implications on variation between the sites.
To conclude the main variation between the sites can be attributed to different habitats at
each site which allow different species to occur as they occupy different niches created by the
habitat causing the variation. However the variation in habitats is caused by variation of
various contributing factors such as physical, chemical and biological interactions and
anthropogenic inputs which create these different habitats and allow the wide variation of
macrofaunal species to occur.
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