Ocean & Coastal Management 103 (2015) 78e85
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Ocean & Coastal Management
journal homepage: www.elsevier.com/locate/ocecoaman
The effects of urbanisation on coastal habitats and the potential for
ecological engineering: A Singapore case study
Samantha Lai a, Lynette H.L. Loke a, Michael J. Hilton b, Tjeerd J. Bouma c, Peter A. Todd a, *
a
Experimental Marine Ecology Laboratory, Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Block S3, Level 2,
Singapore 117543, Singapore
b
Geography Department, University of Otago, New Zealand
c
Department of Spatial Ecology, Royal Netherlands Institute for Sea Research, The Netherlands
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 15 May 2014
Accepted 7 November 2014
Available online 22 November 2014
Habitat loss associated with land reclamation and shoreline development is becoming increasingly
prevalent as coastal cities expand. The majority of Singapore's mangrove forests, coral reefs and sand/
mudflats disappeared between the 1920s and 1990s. Our study quantifies additional coastal transformations during the subsequent two decades, analyses the potential impact of future development
plans, and synthesises the mitigation options available. Comparisons of topographical maps between
1993 and 2011 reveals declines in total cover of intertidal coral reef flats (from 17.0 km2 to 9.5 km2) and
sand/mudflats has (from 8.0 km2 to 5.0 km2), largely because of extensive land reclamation. Conversely,
mangrove forests have increased (from 4.8 km2 to 6.4 km2) due to restoration efforts and greater regulatory protection. However, 15 and 50-year projections based on Singapore's 2008 Master Plan and 2011
Concept Plan show that all habitats are predicted to shrink further as new reclamations are completed.
Such decline may be counteracted, at least in part, if ecological engineering is used to help conserve
biodiversity. The problems exemplified by Singapore, and the potential future solutions discussed in our
paper, provide guidance for urban marine conservation in coastal cities that are experiencing rapid
development and land use change.
© 2014 Elsevier Ltd. All rights reserved.
Keywords:
Coastal change
Coastal management
Ecological engineering
Intertidal habitats
Land reclamation
Seawalls
Singapore
1. Introduction
In 2003, approximately 3 billion people lived within 200 km of
the seada number that is predicted to double by 2025 (Creel,
2003). As coastal cities expand, land reclamation is one of the
few options available to provide space and counteract erosion
(Small and Nicholls, 2003; Charlier et al., 2005), as evidenced by
huge projects in the Netherlands, Tokyo, Taipei, Mumbai, Bahrain,
New Orleans, Macau and Hong Kong (Craig et al., 1979; Al-Madany,
1991; Glaser et al., 1991; Luo, 1997; Yokohari et al., 2000; Murthy
et al., 2001; Charlier et al., 2005; Hoeksema, 2007). Coastal
armouring to protect newly-created shorelines is also increasing,
with addition impetus provided by the threat of sea level rise and
more frequent storms as a consequence of global climate change
(Moschella et al., 2005). The resulting loss of natural shoresdand
gain in artificial onesdhas profound implications for the conservation of marine ecosystems and species in urban settings. The
* Corresponding author.
E-mail address: dbspat@nus.edu.sg (P.A. Todd).
http://dx.doi.org/10.1016/j.ocecoaman.2014.11.006
0964-5691/© 2014 Elsevier Ltd. All rights reserved.
highly urban environment represented by Singapore serves as an
illustrative case study of the ecological future that many coastal
cities, especially those in rapidly developing countries, may eventually face.
Singapore's coastal landscape has been altered extensively,
starting with British colonial establishment in 1819. In parallel with
its rapid development, its shoreline has been shifting seawards via
land reclamation to accommodate ports, industries, infrastructure,
parks, and homes. Hilton and Manning (1995) documented historical shoreline changes in Singapore up to 1993. From 1922 to
1993, areas of mangroves (75 km2 reduced to 5 km2), coral reefs
(32 km2 reduced to 17 km2) and intertidal sand/mudflats (33 km2
reduced to 8 km2) shrunk dramatically. During this time, the percentage of natural coastline dropped from 96% to 40%. Hilton and
Manning (1995) projected that by 2030 land reclamation would
eventually increase the coastline to 532 km. They concluded that
local resources could be better managed to protect biodiversity and
achieve sustainable development.
As coastlines continue to be altered, both in Singapore and
around the world, there is a need for paradigm shift in the way
artificial habitats are perceived and designed. Internationally,
S. Lai et al. / Ocean & Coastal Management 103 (2015) 78e85
79
there is growing interest in the potential to engineer these
structures to improve their capacity to support more bio-diverse
communities while still retaining their engineering function
€ hler, 2008; Chapman and
(Mitsch and Jørgensen, 2003; Ko
Underwood, 2011; Francis and Lorimer, 2011). This process of
combining engineering and ecological principles to reduce the
negative effects of artificial structures is an established form of
ecological engineering (Bergen et al., 2001; Borsje et al., 2011) and
has been applied to seawalls and other coastal infrastructure to
mitigate their ecological impacts (Chapman and Blockley, 2009;
Browne and Chapman, 2011). Ecological engineering of shorelines can broadly be categorised into “soft” and “hard” approaches
(Charlier et al., 2005; Chapman and Underwood, 2011). Soft engineering employs the inclusion of natural elements such as
marshes, mangroves, and sand dunes for coastal defence (Morris,
2007; Bouma et al., 2009). For instance, removing or rearranging sections of seawalls while adding natural vegetation
(Chapman and Underwood, 2011). Soft engineering approaches
often result in the presence of both hard armament and natural
habitatsdsometimes called the “hybrid approach”dreflecting a
gradient in the amount of natural habitat added (where the
extreme end point would be complete restoration of the natural
shore). The hard approach, on the other hand, involves the physical manipulation of artificial structures such as seawalls, usually
by changing their slope angle or altering their topographic
complexity (e.g. Martins et al., 2010; Loke et al., 2014). Even
though both soft and hard ecological engineering have the same
practical goals, they are not universal solutions that will work
equally well in all situations. Soft and hard ecological engineering
strategies are therefore context-dependent and lead to alternate
outcomes as the resulting habitats usually support different assemblages of species. Creating a hybrid environment, e.g.
combining natural vegetation with seawalls, might be feasible in
certain cases (Chapman and Underwood, 2011) but not in others,
for instance, in highly exposed shores.
It has been almost two decades since Hilton and Manning's
(1995) paper was published, during which time Singapore's
physical as well as social landscape has changed significantly. The
resident population has swelled by over 40% to 3.8 million and the
land area has increased by 14% to 714 km2 (Singapore Department
of Statistics, 2013). The length of Singapore's artificial coastlines
has concomitantly increased, while natural shoreline has further
decreased. Reclamation is so extensive along the southern coast of
Singapore that the only remaining natural stretch is a 300 m long
rocky shore (Todd and Chou, 2005), yet little research has been
conducted to quantify these changes and their impacts. By
designing future seawalls or modifying existing ones according to
ecological principles, these structures may eventually host a
greater diversity of native coastal species and hence contribute to
the conservation management plans of this tropical city-state. The
present paper aims to quantify the transformations of Singapore's
coastline since 1993, as well as predict future changes based on
the Singapore Government's 2008 Master Plan and 2011 Concept
Plan (URA, 2008). We also evaluate the environmental problems
arising from shoreline development, and highlight the potential to
incorporate ecological engineering in the design of seawalls.
using the squares method, but differences between the two techniques are likely to be minor. Areas of remaining mangroves
marked on the topographic maps include remnant patches that
once lined two estuaries along the northern coastline, both of
which have now been converted into freshwater reservoirs. These
remnants are no longer connected to the marine environment, and
were therefore not calculated within the total area of mangroves.
On the other hand, some fragments not recorded in the topographic
maps were included based on a contemporary publication by Yee
et al. (2010) which documented the extent of mangroves in 2010.
Accessible areas were ground-truthed by the first author to confirm
their presence in 2013. Our estimates of the intertidal coral reef and
sand/mudflat areas were based solely on the topographic maps. The
coral reef areas marked out on the topographic maps used here
represented intertidal reef flats only. The sub-tidal reef slopes were
excluded, as they were in Hilton and Manning (1995).
The present (i.e. 2012) length of seawalls was determined based
on satellite images from Google Earth (Google, 2009), data collected
from ground-truthing, and observations from various researchers
who have conducted studies around Singapore's coasts. Seawalls
were traced onto the 2011 topographic map using ArcGis 10.0
(ESRI®, 2012) and grouped into three categories: sloping and ungrouted, sloping and grouted, and vertical. Sloping walls generally
have a slope between 14 and 35 (Lee and Tan, 2009) and consist of
granite rip rap that is often grouted with mortar to fill in the
crevices between rocks. Vertical walls are typically made of concrete and are usually found in port areas. Categorisation was based
on the satellite images (the resolution was high enough to discern
between sloping and vertical walls), personal observations, or
inferred from the use of the area (e.g. walls in docks were assumed
to be vertical). The total area covered by sloping seawalls was obtained by multiplying the total length by 10.54 m, i.e. the average
width of seawalls calculated from seawall measurements derived
from Lee and Tan (2009). It was not possible to calculate the average
width of vertical seawalls as these data are not published and the
ports and docks where they are found have restricted access. The
total length of the coastline around Singapore (combining both
mainland and offshore islands) was obtained by adding the nonarmoured and natural lengths of the coastline (the latter was also
digitised using ArcGis 10.0, ESRI®, 2012).
The predicted conversion of coastal habitats over the next
decade, including changes in mangrove, coral reef and sand/
mudflat areas, as well as seawall length, were determined using the
2008 Singapore Urban Redevelopment Authority's (URA) Master
Plan and 2011 Concept Plan. The Master Plan is a statutory land use
plan that directs development over the subsequent 10e15 years
while the longer-termed Concept Plan guides development over
the subsequent 40e50 years (URA, 2008). Natural habitats in areas
that are marked for development were considered to be built over,
and the new resultant coastlines were assumed to be protected
with seawalls. Habitats not directly affected by the developments
were presumed not to have increased or decreased in area.
2. Materials and methods
Our estimates from the 2002 topographical map showed that
total mangrove area in Singapore increased to 6.26 km2 relative to
the 4.87 km2 recorded in 1993 (Hilton and Manning, 1995).
Comparing the distributions of mangroves in Hilton and Manning's
(1995) 1993 map (Fig. 1), it is clear that the bulk of the increase has
occurred at S. Buloh and P. Ubin. Mangroves in areas that remained
undisturbed also expanded, such as on the military training islands
of P. Pawai (0.26 km2 in 1993 to 0.48 km2 in 2002), P. Tekong
Estimates of mangrove, coral reef and intertidal sand/mudflats
were obtained from the 2002 and 2011 1:50,000 topographic maps
published by the Singapore Armed Forces Mapping Unit. The
boundaries of each fragment of habitat were traced in ArcGis 10.0
(ESRI®, 2012) which was also used to calculate planar areas. The
original 1993 estimates by Hilton and Manning (1995) were made
3. Results
3.1. Mangrove forests
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S. Lai et al. / Ocean & Coastal Management 103 (2015) 78e85
(0.73 km2 to 1.62 km2) and P. Senang (0.15 km2 to 0.17 km2). Based
on the 2011 map the total area of mangroves increased marginally
further to 6.44 km2. According to the 2008 Master Plan, however,
more than 33% of this existing mangrove forest is at risk of being
lost. The mangroves in S. Khatib Bongsu/Simpang (0.23 km2), P.
Tekong (0.76 km2) and other small patches along the northern
coast are all slated to be reclaimed, while future development on P.
Ubin threatens another 0.82 km2. If these losses are realised,
Singapore will only retain 5.64% (4.23 km2) of its original 75 km2
mangrove area by the end of 2030.
3.2. Intertidal reef flats
The period between 1993 and 2002 was marked by several
large reclamation projects, by the end of which the area of
intertidal coral reef habitat was just 10.13 km2. The most prominent changes included: 1) the reclamation and combining of the
Ayer group of islands and their fringing reefs into Jurong Island
for the petrochemical industry; 2) the expansion of Sentosa Island to create land for a marina and exclusive residences
(Ramcharan, 2002); and 3) the construction of the bund around
Semakau landfill (Chou et al., 2004), covering the fringing reef of
a neighbouring island, the eastern shore of P. Semakau and the
patch reefs in between. The remaining reef along the coast of P.
Semakau was protected during the reclamation process (Chou
and Tun, 2007) and an extensive 1.23 km2 of reef flat was still
present in 2002.
A total of 9.51 km2 of coral reef remained as of 2011 (Fig. 2). This
additional decline (much smaller, however, than during the 1993 to
2002 period) was due to reclamation works to connect and extend
P. Seringat and Lazarus Island, which resulted in the loss of the
fringing reefs and two small patch reefs northwest of P. Seringat.
Furthermore, the P. Bukom petrochemical complex was expanded
to encompass its neighbouring islands. Three patch reefs currently
present in the unused cell of P. Semakau, totalling 0.39 km2, will
eventually be covered by landfill. Several other reefs are expected
to be lost in the years to come. The small island of P. Tekukor and a
patch reef east of it are slated for reclamation in the 2008 Master
Plan. In the 2011 Concept Plan, two large areas around P. Bukom
and P. Semakau (Fig. 2) are marked out for ‘possible reclamation’,
which could result in the loss of many of the large patch reefs
(totalling 0.59 km2).
3.3. Sand and mudflats
In the decade between 1993 and 2002, the total area of sand/
mudflats in Singapore dropped only slightly to 7.63 km2, mostly
due to small losses along the northern coast of P. Tekong (0.33 km2)
and the eastern coast of P. Ubin (0.21 km2). However, by 2011,
reclamation at P. Tekong encompassed several neighbouring
islands and their sand and mudflats, after which the country-wide
total of this habitat was 5.00 km2 (Fig. 2).
Future estimates based on the Master Plan show that the area of
sand/mudflats will decline to 2.65 km2 within 10e15 years from
2008. The bulk of the loss will come from the completion of the P.
Tekong reclamation (which is currently underway) (1.28 km2) and
from the eastern coast of P. Ubin, where approximately 1 km2 of
sand flats is to be reclaimed.
3.4. Present coastline and seawall distribution
The length of the Singapore coast has increased significantly
over the past two decades as a result of reclamation, following the
trend predicted by Hilton and Manning (1995). Based on the 2011
map, the total length of coastline is 505 km (compared to 480 km in
1993), and this figure will continue to climb with the completion of
the reclamation works in P. Tekong and Tuas Industrial Estate.
Currently, the total length of seawalls is 319 km, constituting 63.3%
of the coastline. Of these, 5.5% are sloping and grouted, 41.0% are
sloping and un-grouted, 26.9% are vertical (26.6% could not be
verified from satellite images and/or were not accessible for
ground-truthing). The estimated total area of the sloping seawalls is
1.85 km2. Unsurprisingly, the locations with the most seawalls are
those that have undergone the most reclamation work, e.g. Tuas
(59 km), Jurong Island (47 km) and Changi (19 km) (Fig. 3).
By 2030, it is expected that Singapore's coastline will exceed
600 km (Fig. 4), surpassing Hilton and Manning's (1995) estimate of
531 km for the same date. The ratio of artificial to natural coastline
Fig. 1. 2011 distribution of mangroves in Singapore (from present study, in red) with the 1993, 1975 and 1953 distributions (from Hilton and Manning, 1995, in black) for comparison. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
S. Lai et al. / Ocean & Coastal Management 103 (2015) 78e85
81
Fig. 2. 2011 distribution of coral reefs (in blue) around Singapore's Southern Islands and sand/mudflats (in pink) around P. Ubin and P. Tekong. (For interpretation of the references
to colour in this figure legend, the reader is referred to the web version of this article.)
will change, with seawalls and created beaches increasing from 83%
(2011) to 86% (2030) of total coastline length. If all the land reclamation efforts proposed in the 2011 Concept Plan are carried out
(including the “possible future reclamation” areas near P. Semakau
and P. Bukom), an additional 125 km of seawalls can be expected to
be constructed within the next fifty years.
4. Discussion
It is apparent that many of the natural coastal habitats in
Singapore face similar fates, viz. (1) shrinking area, (2) increasing
fragmentation, and (3) encroachment by urban expansion. These
processes commonly degrade ecosystems found within or near
highly urbanised areas (Chapman and Underwood, 2011). The results of our study show that mangrove forest areas increased between 1993 and 2011, due to improved environmental protection
and various reforestation efforts (Yee et al., 2010). However, if the
2008 Master Plan is fully executed, more mangrove patches will be
reclaimed to create land for development, reversing this positive
trend and causing the mangroves to be further fragmented. This
may interfere with propagule import and export, and eventually
lead to genetic isolation. Disturbance from industrial areas in the
north of Singapore near many of the mangrove patches could
further compound the negative effects of fragmentation (Friess
et al., 2012).
Intertidal coral reefs have experienced reductions in area since
1993 due to reclamation projects, which have resulted in loss of
coral diversity and abundance over the past two decades. Two
species of corals, Stylophora pistillata and Seriatopora hystrix have
not been seen in recent years (Chou, 2006) and coral cover has
declined at numerous sites, for example, as much as 73% was lost at
a reef off P. Hantu between 1986 and 2003 (Chou, 2006). Several
studies have indicated that the reefs and their associated fauna are
in decline due to sedimentation and turbidity caused by on-going
land reclamation and dredging operations (Chou et al., 2004;
Dikou and van Woesik, 2006; Hoeksema and Koh, 2009). Similar
anthropogenic effects on natural systems have been recorded in
major coastal cities worldwide (Hodgson, 1997; Santos, 2000;
Yeung, 2001), and will likely increase in extent and intensity as
they expand.
The extent and effects of habitat loss may not always be quantifiable because of the paucity of historical information on species
distributions. Intertidal sand and mudflats in Singapore have
declined substantially during the past two decades; however, information regarding the ecological impact of these reductions is
limited, in part due to the lack of previous surveys. Contemporary
studies indicate that diverse communities thrive in the remaining
patches, and we assume that similar communities have been lost at
sites where sand and mudflats were reclaimed. For example, initial
reports from the Comprehensive Marine Biodiversity Surveyda
consolidated effort by government agencies, academics, and
volunteer groups to document Singapore's marine biodiversitydrevealed that biodiversity in the country's mudflats is
relatively high with 77 fish species, 62 snail species and 37 crab
species recorded (National Parks Board, 2012). Monitoring by local
groups has also determined that seagrass meadows on sandflats are
diverse and not declining (Yaakub et al., 2013, 2014). Continuous
monitoring of the health of remaining natural habitats improves
environmental awareness, and allows for more informed management decisions. For these reasons, it is important that coastal
cities in the early stages of expansion quickly establish monitoring
efforts to establish baselines and track changes.
A further decrease in extent and quality of Singapore's coastal
habitats seems inevitable if the reclamation efforts proposed in the
2011 Concept Plan are fully realised. Nevertheless, the anthropogenic structures that take their place can potentially serve as habitats for coastal species. Furthermore, given that the majority of
Singapore's coastline is already artificial, it is crucial to see beyond
the negative impacts of such structures, and recognise their latent
role in the conservation of coastal biodiversity. As Chapman and
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S. Lai et al. / Ocean & Coastal Management 103 (2015) 78e85
Fig. 3. 2011 distribution of seawalls (in orange) around Singapore. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of
this article.)
Fig. 4. Singapore's coastline changes proposed in the 2008 Master Plan (blue) and 2011 Concept Plan (red dotted line). (For interpretation of the references to colour in this figure
legend, the reader is referred to the web version of this article.)
Underwood (2011: 303) emphasise: “now is the time to stop
wringing our hands in dismay that little can be done about the
problem and to be pro-active in attempting to build shorelines in a
manner that will meet societal needs, constraints of engineering
and costs and which will also cause less impact and/or provide
improved habitat for species other than humankind.” Despite the
huge quantity of seawalls in Singapore, few studies have attempted
to document the type of assemblages that live on them. The limited
research conducted to date has, nevertheless, shown that a variety
of intertidal and sub-tidal communities occupy these structures. An
island-wide survey of twelve seawalls revealed 30 marine
autotrophic taxa and 66 invertebrate taxa (Lee and Tan, 2009), as
well as several new records of algae (Lee et al., 2009). In addition,
coral assemblages were discovered on seawalls in a yacht club, with
over 1700 colonies from 37 genera recorded (Tan et al., 2012), while
sub-tidal portions of seawalls in the Southern Islands have been
found to host coral communities with densities averaging 17 colonies per m2 (Ng et al., 2012). These findings suggest that armoured
coasts could serve as a refuge for some species when their natural
habitats are removed. More research, however, is required to better
understand the processes that shape and maintain the communities on such structures, so as to make useful predictions regarding
S. Lai et al. / Ocean & Coastal Management 103 (2015) 78e85
the assemblages that will likely result from different engineering
scenarios, and offer scientifically grounded advice on the construction of new coastal defences.
Awareness of the potential for ecologically engineering the
marine environment is still at an early stage, and much more
needs to be done before it can be applied practically on a large
scale (Bouma et al., 2009). A flow-diagram of possible mitigation
measures for Singapore's various coastal environments are presented in Fig. 5, where both the ‘hard’ and ‘soft’ approaches to
ecologically engineer coastal defences are highlighted and summarised based on the current state of knowledge regarding
feasibility. Soft engineering using coastal vegetation such as
Spartina sp. has been attempted along the coasts of Tianjin, Fujian
and Guangdong in China, and New England in USA, and improvements to shoreline stabilisation, sedimentation control, and
faunal abundance have been reported (Bruno, 2000; Chung, 2006).
For sites that already have existing seawall protection, the “hard”
approach is a more feasible alternative. The great majority of attempts at enhancing seawalls can be categorised into one of two
strategies: either decreasing the slope or manipulating the surface
of the substrate (Chapman, 2003; Chapman and Underwood,
2011). Steep or vertical seawalls reduce the available area for organisms and increases the interactions (and competition) among
species living at different tidal heights (Bulleri and Chapman,
83
2010; Klein et al., 2011). Reducing the slope of the wall can
counteract this and improve species abundance and richness.
However, past studies have shown that this is also dependent on
the environmental conditions of the site, and may not be a viable
solution for all locations (Chapman and Underwood, 2011).
Manipulation of the substrate, on the other hand, is more widely
applicable, and less costly to implement. It could range from
increasing substrate complexity, to introducing novel habitats (e.g.
rock pools, large crevices) to suit the ecological niches of the target
intertidal organisms (Chapman, 2003; Moreira et al., 2007;
Chapman and Blockley, 2009; Firth et al., 2013; Loke et al., 2014).
Results from recent studies on enhancing seawalls have been
promising. The addition of small pits ~12 mm in diameter to basalt
rock walls in the Azores archipelago, Portugal, significantly
increased the abundance of the limpet Patella candei d’Orbigny via
immigration and recruitment (Martins et al., 2010). The authors
hypothesised that small limpets experienced lower mortality when
after finding refuge in the pits (Martins et al., 2010). Another
experiment conducted in the United Kingdom showed that concrete blocks with small pits and larger crevices had a significantly
higher diversity than blocks that were completely smooth
(Moschella et al., 2005). Rock pools created at the bottom of the
seawalls also had double the number of species on average
compared to parts of the wall which drained freely. Many of these
Fig. 5. Potential mitigation options/measures for the different types of coastal habitats in Singapore (in blue). The ecological engineering of shorelines is split into ‘hard’ (in orange)
and ‘soft’ (in green) approaches; based on either approaches, coastal defence could either be constructured de novo or by making alterations to existing armour. (For interpretation
of the references to colour in this figure legend, the reader is referred to the web version of this article.)
84
S. Lai et al. / Ocean & Coastal Management 103 (2015) 78e85
species were desiccation-sensitive, and would not have been able
to exist on the seawall without the microenvironment created by
the rock pools (Moschella et al., 2005). Researchers in Singapore are
currently experimenting with cement tiles moulded with various
patterns to increase the complexity of the seawall surfaces (Loke
et al., 2014). Community comparisons between local seawalls and
rocky shores have indicated that low primary-productivity is
limiting trophic complexitydand consequently the diversitydthat
can be supported on these artificial structures around Singapore's
shores (Lai, 2013). Future efforts should focus on removing this
constraint to increase the carrying capacity of seawalls. Advances in
engineering seawalls to increase the number of species they are
able to support may help maintain the biodiversity of coastal cities
worldwide.
Ecological engineering has the potential to be a powerful instrument in urban conservation. The most efficacious way to achieve implementation is via a top-down approach to ensure
coordination among the various agencies that are involved in
coastal planning. In Singapore, awareness of marine environmental
issues has increased, and attitudes towards them have become
more positive over the last two decades. One notable example of
the commitment to marine conservation is the case of Chek Jawa,
an intertidal sand flat with rich biodiversity. The site was slated for
reclamation in 2001, but a surge of public interest and subsequent
outcry eventually culminated in the deferment of the project (Wee
and Hale, 2008; Geh and Sharp, 2008). More recently, public
funding has also been allocated for research into small scale applications of ecological engineering in Singapore (Low, 2012; Loke
et al., 2014), as well as for detailed studies of a range of coastal
marine organisms such as hard corals (Huang et al., 2009), sea
anemones (Fautin et al., 2009) and giant clams (Neo and Todd,
2012).
Singapore's marine management challenges illustrated in the
present paper are by no means unique. As cities expand and their
coastlines develop, the loss of natural habitats and their associated
biodiversity is likely to accelerate. While conservation of original
habitats is clearly desirable, this is not always viable. Thus, it is
becoming increasingly necessary for coastal cities to invest in
research, development and implementation of alternate strategies
for biodiversity conservation. Ecological engineering is an attractive
option that strives to provide opportunities for marine conservation where development is both intensive and inevitable. In
Singapore, converting the ubiquitous seawalls into surrogate habitats for coastal species is still at a nascent stage. However, Singapore's endeavours, and solutions, to finding a balance between
conservation of its shores and development can help inform urban
marine sustainability planning in other coastal cities facing similar
challenges.
Acknowledgements
This research was carried out as part of the Singapore Delft
Water Alliance JBE-B project: “Towards designing innovative
coastal protection using ecosystem-based approaches; deriving
underlying ecological knowledge” (grant number R-303-001-021414). The authors would like to thank the SAF Mapping Unit for
permitting the use of their topographical maps for this study.
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