Environment - Tropical Shelf Seas and Shores
Building with Nature BwN Guideline Environments Project phases Governance BwN Knowledge base
Sandy Shores
Estuaries
Delta Lakes
Shelf Seas and Shores
LogTropical
in
Coastal Seas
General
General
Nearshore estuarine and marine ecosystems, such as seagrass
meadows, marshes, mangrove forests and coral reefs serve many
important functions in tropical coastal waters. These ecosystems
have a high primary and secondary productivity and support a great
abundance and diversity of fish and invertebrates (Blaber et al.,
2000, Beck et al., 2001).
The seabed of tropical coastal waters can be rocky, sandy, muddy or a
mixture of these. Depending on the bed composition, mangrove forests,
seagrass meadows and coral reef ecosystems can be found. These
fragile, biologically diverse ecosystems thrive in the warm, wet tropics. Up
welling of nutrient-rich waters supports large populations of microscopic
plants and animals, resp. called phytoplankton and zooplankton.
Plankton, in turn, feeds many species of fish and other marine life. People
in turn depend on harvesting this flora and fauna.
In this part we describe tropical shelf seas and shores. For information on
temperate coastal seas see here and for temperate sandy shores see her
e.
Mangroves
Seagrass meadows
Within the Building with Nature sub-program on tropical coastal shelf seas
Coral
and shores we focus on the coast of Singapore and its neighbouring
countries Malaysia, Thailand and Indonesia. These waters are confronted
with increased turbidity levels and coastal erosion, due to river inputs and anthropogenic activities. This may affect coastal ecosystems and
habitats.
System Description
System description
Although the tropics are formally defined by their latitude (between Cancer and Capricorn), it is more convenient from a physical
point of view to define tropical seas by their physical characteristics (temperature and precipitation) and ecological properties
(reflected in the occurrence of e.g. corals, mangroves and seagrasses). This means that some coastal seas and shorelines partly
located in the subtropics can be regarded as tropical systems.
Ecological system
Three types of ecological communities are
specifically found in tropical shelf seas and
shores, viz. seagrasses, mangroves and coral
reefs.
Seagrasses comprise a functional group of about
60 to 70 species of underwater marine flowering
plants worldwide. They grow primarily on soft
substrates from the intertidal area down to
maximum depths of around 70 m. In shallow
(coastal) waters, they can form dense meadows
that constitute valuable and often overlooked
habitats that provide important ecological (and
economical) functions and services, for example
breeding habitats of fish and turtles, shelter for
hundreds of marine fish species against their
predators and food for mega-herbivores such as
green sea turtles, dugongs and manatees.
Seagrasses often occur in proximity to coral
reefs, mangroves, shellfish reefs and other
marine ecosystems, with which there can be
significant ecological interactions.
Mangroves are forests growing in tropical and
sub-tropical tidal areas. The forest consists of
tree species that can tolerate regular flooding by
saline seawater. This tolerance is due to one of
the most distinct characteristics of the mangrove
trees: aerial roots which are exposed to air part of
the day. These enable them to survive in anoxic
sediments.
Coral reefs a are well-recognized feature of
tropical oceans. The seas surrounding tropical
islands and low-latitude continental shelves away
from major river deltas are ideal for coral reef
formation. Over millennia, very large reefs have
formed in the Caribbean Sea, and especially in
the southwest Pacific Ocean. Coral reefs are
impressive three-dimensional structures built up
over many centuries by small, coral polyps that
live in symbiosis (mutual beneficiary relationship)
with microscopic algae, called zooxanthellae.
These algae require light to grow, so coral reefs
only occur in areas that receive enough light. The
depth to which coral reefs can occur therefore
depends on the interplay of depth and the
transparency of the water. The coral polyps
protect the algae against predators; the algae
provide the coral with excessive sugars. Together
they can extract calcium carbonate from
seawater to build their limestone skeleton as the
coral polyps bud and grow. Over time massive
coral reefs structures are formed by these reef
builders which create habitat for many other
species.
Physical drivers
Global distributions of mangrove, seagrass meadows and coral
reefs
Seagrass
Mangroves
Corals
Global sea surface temperature
Annual discharge of suspended sediment and sediment yield
Important physical drivers of the tropical coastal system differ from their temperate counterparts in a number of aspects:
1. The weather system is monsoon-dominated, which results in a seasonally varying precipitation and wind climate. This seasonal
variation is more pronounced than in temperate zones. Precipitation variation is reflected in fluvial water and sediment supply, wind
climate variation yields varying residual currents.
2. Diurnal tides tend to be more pronounced in tropical than in temperate coastal seas (Hoitink et al., 2003). This yields relatively
variable tides, often displaying a pronounced seasonal variation and low-frequency currents (van Maren & Gerritsen, 2012).
3. Solar irradiation, and therefore sea surface temperature, is higher and more constant than in temperate regions. This promotes
ecosystems that are typical for the tropics, with little or no seasonal variation in vegetation.
4. The sediment yield in the tropics is larger than in temperate regions (Milliman & Meade, 1983). This is the result of strong weathering,
in Asia also combined with a relative abundance of mountainous islands and the Himalayas.
As a combined result, tropical coastal seas show a strong seasonality in water levels, current patterns, discharge and sediment load, whereas
water temperature and vegetation exhibit a weak or even zero seasonal variation.
Governance system
Besides coastal protection important issues in the environment of tropical shelf seas and shores are often the provision of food or earnings by
tourism from the sensitive ecosystems such as coral reefs. Local communities are key stakeholders as they heavily depend on the services
that these ecosystems provide. Also many different (worldwide) organizations and NGO’s such as the WWF are important actors, as they put
their focus on the protection of the tropical environment.
Results of the efforts of the NGO’s and organizations that act on an international level are the presence of Marine Protected Areas and the
enforcement of international guidelines. In case of the development of marine infrastructure projects these guidelines can for example dictate
the relocation of ecosystems or the compensation of their loss. The Worldbank has its own guidelines regarding the environment and if a
development is undertaken with a loan, it imposes its rules and regulations. Local regulation however, if any, usually overrules the Worldbank
regulation.
For more information on governance processes see Governance.
Ecosystem services
Ecosystem services
Natural ecosystems in general provide a multitude of resources and services to mankind. Collectively, these benefits are known as ecosyste
m services. The issue of ecosystem services has been discussed for decades. In 2004, the United Nations Millennium Ecosystem
Assessment (MEA), and more recently 'The Economics of Ecosystems and Biodiversity' (TEEB) studies, divided the ecosystem services into
four categories:
provision, such as the production of food and water, or the availability of mineable resources;
regulation, such as the control of climate and disease;
cultural, such as spiritual and recreational benefits; and
support, such as nutrient cycles and crop pollination.
Provision services
150 types of coral in
Singapore
The ecosystem services provided by tropical coastal ecosystems are described below.
This category concerns the products to be obtained from ecosystems. Examples of products provided by tropical coastal ecosystems are
listed below.
Food i.e. fish, shellfish, invertebrates. Mangrove forests, seagrass meadows and coral reefs provide habitat for a diverse flora and
fauna, which constitute an important food source.
Biodiversity and genetic resources. Mangrove forests, seagrass meadows and coral reefs support a great abundance and diversity of
fish and invertebrates.
Materials i.e. charcoal, coral mining. Mangrove forests are source of wood (e.g. for fuel), while coral reefs have been mined to extract
lime for building construction. Seagrass may be used for preserving (moistening) fisheries products such as crabs.
Regulation services
Benefits that arise from how a system regulates processes, resources and its own properties are called regulation services. Benefits obtained
from regulation by tropical coastal ecosystems are the following.
Erosion control/stabilization of sediment. Mangrove forests and seagrass meadows retain soil between their root structures and
provide sediment stabilization, thus preventing or mitigating the loss of soil (erosion) by erosive processes caused by wind, river
run-off or wave energy.
Coastal protection. Mangrove forests, seagrass meadows and coral reefs dissipate hydrodynamic energy, such as wave energy, and
thereby protect their hinterland.
Disruption of fresh water discharge. Mangrove forest slows down the fresh water flow to sea, therewith increasing the fresh water
availability in inland areas.
Nutrient filter. Mangrove forests and seagrass meadows act as nutrient filters for terrestrial waters flowing through them. Nutrients
are absorbed in the system, thus preventing them to fertilize the sea.
Nitrogen fixation. Coral reefs can fixate nitrogen in nutrient-starved environments, where nitrogen may be of major importance to
primary production.
Pollution fixation. Mangrove forests and seagrass meadows fixate pollutants.
Re-mineralization of in-organic and organic materials.
Supply of organic material to surrounding ecosystems.
Oxygen production. Mangrove forests and seagrass meadows convert CO2 into O2.
Carbon sequestration. Mangrove forests, seagrass meadows and coral reefs act as a carbon dioxide sink and capture carbon dioxide
through biogeochemical activity, sedimentation and biological activity.
Water catchment and groundwater re-charge by mangrove forests.
Cultural services
These are non-material benefits people obtain from ecosystems.
Education and scientific resources. Mangrove forests, seagrass meadows and coral reefs are important subjects of scientific
research and education.
Climate change record. Coral reefs are slowly growing structures, taking many years to gain large proportions. Therefore, their
internal structure can serve as a proxy for climate changes in the past.
Possibilities for recreation such as fishing, scuba-diving, etc. Especially seagrass meadows and coral reefs provide many
opportunities for recreational activities.
Cultural, spiritual and artisan values. Mangrove forests and coral reefs are of importance as spiritual locations and as inspiration for
artistic activities.
Aesthetic values. Mangrove forests, seagrass meadows and coral reefs provide scenery that is often appreciated for its beauty.
Supporting services
Some services are necessary for the production of all other ecosystem services, without yielding direct benefits to humans. Examples from
tropical coastal ecosystems are:
Nursery habitat; mangrove forests, seagrass meadows and coral reefs provide feeding and breeding grounds to a large number of
species, including many of economic importance.
Resilience to human impact and natural hazards: mangrove forests, seagrass meadows and coral reefs may assist in recovery after
natural or human-induced disasters.
Top soil formation: Mangroves aid soil formation by trapping sediment and debris. Also their roots and pneumatophores accumulate
sediments.
Refuge area: mangrove forests, seagrass meadows and coral reefs provide multiple species with shelter.
Cross-ecosystem nutrient transfer by coral reefs.
Ecosystem values
The table below (Modified after Barbier et al., 2011) gives an impression of the monetary value of some of these ecosystem services. The
original valuation estimates are not expressed in standardized units because of possible misinterpretation.
Ecosystem
Service
Ecosystem service value examples
Location
Coral reef
Coastal
protection
US$1,74.ha-1.yr-1
for Indian Ocean based on impacts from 1998
bleaching event on property values
Fisheries
US$15-45.000.km-2.yr-1 in sustainable fishing for
local consumption and
US$5-10.000 for live-fish export
The Philippines
Tourism
US$88.000 total consumer surplus for 40.000
tourists to marine parks
Seychelles
Seagrass
beds
Maintenance
of Fisheries
loss of 12.700ha of seagrasses; associated with
lost fishery production of AU$235.000
Australia
Mangrove
forest
Raw materials US$484-585.ha-1.yr-1 capitalized value of
and food
collected products
Thailand
Coastal
protection
US$8.966-10.821 ha-1 capaitalized value for storm Thailand
protection
Erosion
control
US$3.679.ha-1.yr-1 annualized replacement costs
Thailand
Maintenance
of Fisheries
US$708-987.ha-1 capitalized value of increased
offshore fishery production
Thailand
Carbon
Sequestration
US$30.50.ha-1.yr-1
World wide
BwN opportunities
BwN opportunities
In tropical environments, the livelihoods of communities often depend strongly on ecosystem services. Understandably the focus in less
developed areas is on socio-economic developments, but these are not always realised in a sustainable manner.
The Building with Nature approach aims at realising socio-economic developments paying full attention to environmental processes in order
to achieve sustainability. Additionally, the Building with Nature approach looks for opportunities to optimize natural processes and enhance
ecosystem services.
Large-scale civil engineering infrastructure developments are essential for economic growth and safety in deltas and coastal areas. Extensive
land reclamations continue to provide new land needed to sustain the anticipated growth of population and economy in the region. It is a
major challenge to develop of an area and at the same time increase or maintain the ecosystem services of the environment. The Building
with Nature sub-program for tropical shelf seas and shores focuses on two themes:
1. Ecosystem-based management of dredging operations; and
2. Eco-dynamic design of coastal protection systems.
Ecosystem based management of dredging operations
Traditional approach
Marine infrastructure development projects (involving dredging, reclamation and construction works) are crucial for coastal protection and
economic development of delta and coastal regions, including harbours and industrial activities. In tropical regions, these infrastructure
development activities often take place in the vicinity of valuable and vulnerable marine nature. Dredging activities, for instance, may cause
sediment stress that affects sensitive marine ecosystems such as coral reefs and seagrass meadows.
Current environmental legislation typically focuses on the potential adverse impacts of such development projects. Dredging operations often
have to observe rigid limits on dredging-induced turbidity to protect the marine ecosystems, limits that have been copied from elsewhere or
presume long-term exposure. It is quite possible, however, that exceeding such limits temporarily is not harmful to the ecosystem, as long as
it does not continue for too long. On the other hand, if the ecosystem is exposed to sediment concentrations below the limit for an extended
period of time, this can have disproportionate effects and may even alter the system’s sensitivity to short-term ‘storm-like’ pulses.
Insights into the site-specific responses and thresholds of corals and seagrass in relation to sediment stress, including the effects of earlier
sensitization and the ability to recover, offer opportunities to shift from the current emission-based norms towards impact-based norms. An
impact-based approach will result in lower costs for mitigation as system knowledge increases and 'worst-case' assumptions can be avoided.
Building with Nature approach
As mentioned before, increased turbidity and sedimentation as a result of anthropogenic activities can be a significant threat to tropical
marine ecosystems such as coral reefs and seagrass meadows. In some regions with a high background turbidity and sedimentation
however, these ecosystems show a certain degree of tolerance and resilience to such stress events. This leads to the hypothesis that coral
and seagrass ecosystems will be able to tolerate anthropogenic sediment stress to an extent that falls within the range and frequency of the
natural variability of these parameters.
In order to realise the shift from an emission-based to an impact-based approach, it is important:
to generate knowledge on the critical thresholds of these marine ecosystems and the factors that contribute to their recovery
potential. Such knowledge is essential to better predict the effects of dredging and marine infrastructure development, to set realistic
and ecologically meaningful indicators and norms for marine construction operations and for a sustainable management of these
sensitive ecosystems.
to integrate knowledge and models into a generic rapid assessment tool that quantifies the cause-effect chain, in support of the
ecodynamic design process, the sustainable execution of marine construction operations and the communication thereof. This rapid
assessment tool can also serve as a tool for adaptive management of dredging operations.
Eco-dynamic design for coastal protection
Traditional approach
The traditional design of coastal protection primarily focuses on protection of the land against flooding and retention of beach sediments for
recreation purposes. Besides these primary goals, limited attention is paid to accompanying coastal aspects, such as the preservation or
development of ecological value. This often results in hard, steep (often vertical) structures on the interface between water and land, leaving
hardly any space for natural processes to play a role in local habitat development. Under natural circumstances, the transition between land
and water is a bio-diverse area providing a suite of ecosystem services. This transition zone would require a wider stretch of coast than the
traditional hard structures, which is not always plainly ideal to the coastal managers because of the space requirement. Coastal land is
extremely valuable, thus the traditional train of thought is that it is more ideal to implement a coastal protection solution which utilizes the least
amount of space, thus maximizing the remaining coastal space for community use.
Building with Nature approach
Many coastal ecosystems in the tropics (mangroves, sea grass meadows and reefs) are known to contribute significantly
Opportunities
to coastal protection and to provide many valuable ecosystem services. For example, some experiments in Singapore ha
ve showed that it is possible to improve biodiversity on hard coastal infrastructural works while maintaining the primary functionality. Hence,
coastal ecosystems could benefit greatly from infrastructural works that enhance local biodiversity. Alternatively, soft solutions can also be
employed to address coastal protection needs, such as have been implemented along the dutch coast (Case - Sand Engine Delfland). In this
transitioning time period from traditional solutions to eco-dynamic solutions, hybrid solutions are likely the most common way forward. A good
example of a hybrid solution in a tropical environment is that which has been proposed for East Coast Park, on the southwestern shores of
Singapore (Case - East Coast Park (ECP) Design Pilot). In this proposed conceptual design (Tutorial - Building with Nature Design), a suite of
Eco-Dynamic Design (a.k.a. Building with Nature Design) components have been integrated to obtain a possible solution which addresses
the structural erosion in combination with enhancing both the recreation and ecological value of this highly utilized public park.
An eco-friendly design requires integrating ecosystem requirements from the start of the design process. This creates opportunities to
‘improve’ (i.e. to enhance functionality and/or diversity) and extend coastal ecosystems while realizing engineering objectives. As many of
these ecosystems offer valuable ecosystem services (e.g. wave attenuation, food production, etc.), such a design may be economically more
attractive than a traditional design.
To seize the opportunities for ecodynamic designs for coastal protection:
Use existing and newly developed knowledge on the habitat requirements of the ecosystems involved.
Gain insight into how the relative physical, ecological and socio-economic systems behave; why are certain ecosystem
characteristics absent / present and how can the system be stimulated to provide the necessary services?
Herewith, eco-designs for soft and hard coastlines in tropical environments can be developed that enhance the ecological potential of the
system while realising the functionality required for the area (i.e. recreation, shipping, industry, safety, etc.). More a practical example of how
this works, please refer to the East Coast Park Design Pilot (East Coast Park (ECP) Design Pilot)
Case examples
Case examples
Within the Building with Nature research program, the regional coastal waters around Singapore were the focus of one of the case studies.
The tropical coastal waters around Singapore are turbid, thus providing an ideal environment for a specific component of these studies, viz.
the ecosystem’s potential to deal with turbidity. For comparison, also clearer tropical shelf seas and shorelines were investigated in the region
(e.g. Indonesia, Malaysia and Thailand).
Ecological System of Singapore Marine Waters
Like elsewhere, seagrass meadows in Singapore play a vital role in supporting
coastal and marine communities and in maintaining a diverse flora and fauna.
They are important to fish productivity and play an important role in maintaining
coastal water quality and clarity. The seagrasses of Singapore are also
important food for marine green turtles and dugongs. To date, a total of 12
different seagrass species have been recorded in Singapore (Yaakub, 2008;
McKenzie et al., 2009).
The foundation tree species (i.e. the most abundant species building the
system) in the mangroves around Singapore typically follow a clear zonation
along the elevation gradient, going from the sea-side towards the higher and
less inundated areas. Mangroves around Singapore contain several flagship
species (i.e. species appealing to the broad public and/or of particular interest
to conservation). The most appealing is probably the long-tailed macaque
monkeys ( Macaca fascicularis ) that live by digging up mud crabs. Another of
the most characteristic species is the mudskipper, which is an early
evolutionary species reflecting the transition from sea to land. Mudlobsters ( Th
allasia anomala ) are remarkable because of the large mounds they can create.
Map SE Asia
Male fiddler crabs ( Uca spp.) can not be missed on the mudflats, waving their
one large claw to court females. The spitting archerfish (Toxotes jaculatrix) is remarkable in that it ‘hunts’ insect by shooting them using a jet
of water. Bats living in the mangroves (e.g. lesser dog-faced fruit bat, Cynopterus brachyotis and long-tongued nectar bat ( Macroglossus
minimus ) are highly important for pollination of some of the mangrove tree species like sonneratia.
Despite major losses in the last half century, the coral reefs of Singapore still have high species richness: more than 250 species of hard or
"stony" corals from 55 genera, providing habitat for more than 120 reef fish species from 30 families.Within Case Singapore, a coral breeding
workshop was carried out at the Tropical Marine Science Institute, on Saint John's Island (off the southern coast of Singapore). The workshop
was led by SECORE, where over the course of one week the participants were taught essential hands-on techniques, such as the collection
of coral gametes during spawning events, fertilization techniques in the lab, rearing of embryos, maintenance of larval cultures, and about the
settlement and transport of larvae.
For additional information on the Singapore ecological system, please refer to Singapore QuickScan
Physical System of Singapore Marine Waters
The physical dynamics of the coastal waters around Singapore are dominated by the tidal regime and the wind patterns of the South China
Sea, as well as by the local river discharges The wave climate is relatively mild (wave heights < 1m). The large-scale currents in the South
China Sea are generated by the annual variation of the monsoon winds
and by tides with a pronounced spatially varying dominance of
semi-diurnal and diurnal tidal constituents. This may lead to very strong
current anomalies in Singapore Strait.
Several small rivers drain into the coastal waters around Singapore. The
largest of these is the Johor River, flowing into the Johor Estuary, a
drowned river valley. Several smaller river systems flow into the Johor
Strait from Malaysia. From Singapore, the Punggol, the Sungei Buloh, the
Sungei Kranji, the Sungei Seletar, the Sungei Serangoon flow into the
Johor Strait while the Sungei Kallang drains into Singapore Strait. The
discharges of the smaller rivers are poorly known, but the discharge of the
Johor River has a long-term mean value of 37.5 m3/s and varies between
70 m3/s in December to around 30 m3/s from February to October. The
sediment load of these rivers is hardly known, though one study gave an
average sediment concentration for the Johor River of 79.8 mg/l, with
minimum and maximum values of 35 mg/l and 164 mg/l, respectively.
Photo by Jamie Craggs
The seafloor in most of Singapore's coastal waters is covered with unconsolidated sand and mud. Mudflats and mangrove forests border the
estuaries draining into Singapore's coastal waters from Malaysia, especially along the Johor Estuary. Measurements show that sedimentation
rates in the Strait of Johor and the Johor estuary vary from around 20 (Johor estuary and parts of the Straits) to several thousands of mg/cm2/
year (Johor Strait). Around Singapore, turbidity was not measured until recently, and therefore its apparent increase is mainly based on
qualitative or semi-quantitative observations. The maximum water depth at which coral reefs and seagrass meadows occur, for instance, has
decreased over the last few decades (i.e. since 1965). The present-day suspended sediment concentration along the west coast of the
southern islands of Singapore is typically between 5 and 20 mg/l.
For additional information on the Singapore physical system, please refer to Singapore QuickScan
Case Study Singapore
The high population density and rapid socio-economic development of Singapore in the last decades has led to extensive land reclamation
works. New beaches, industrial parks, commercial and housing development, port and airport facilities, and other important infrastructures
have increased the surface area with nearly 20%. These reclamation works strongly influence the hydrodynamics and sediment dynamics
around Singapore, by modifying residual currents and maximum flow velocities, and by creating low-energy sheltered areas. The construction
phase, with extensive dredging activities, has had a temporary environmental effect. Forest clearance enhancing upland erosion and
catchment urbanisation enhancing flash floods have both increased the sediment input into the sea.
The Singapore sub-program focuses on two themes, viz.:
1. prediction and monitoring of species response to sedimentation and turbidity;
2. guidelines, knowledge and designs for bio-diverse coastal protection.
Prediction and monitoring of species response to sedimentation and turbidity
Impact assessment studies typically focus on the prevention of adverse impacts of Marine Infrastructure Development (MID) projects,
including the construction and operation phase. Often this is done by limiting measurable physical parameters such as turbidity, overflow
volume or sedimentation. Unfortunately, the criteria and the associated restrictive measures often lack local ecological meaning and are
scientifically poorly underpinned. The Singapore sub-program aims at filling up this knowledge gap as much as possible.
The main objectives of the sub-program are:
(1) to develop so-called species response curves for coral and seagrass in Singaporean waters;
(2) to develop a prototype numerical tool for rapid assessment of species response to the effects of dredging operations;
(3) to identify early warning indicators for negative species response during these activities.
The program involves the following activities:
Mesocosm experiments in which corals and seagrass are subjected to variable levels of shading- and sedimentation. In the
experiments, not only the magnitude, but also the duration of the stress factor is manipulated, and the responses of tolerant and
sensitive species are compared. Post-stress recovery and the effect of repetitive stress events on sea grass are also examined by
monitoring recovery in experimental (man-made) gaps and artificially buried plots in the field.
Monitoring at three coral reefs in Singapore to assess the natural variability in Suspended Particulate Matter (SPM) concentrations,
light exposure, sedimentation and coral response. These data are used to develop species and community response curves, to be
included in the relevant modules of the interactive dredging design tool.
Development of an Interactive Dredge Planning Tool, a rapid assessment tool to determine dredging-induced stressor intensity levels
in an area and to generate maps of the predicted ecological effect. This tool can also be used to generate dredging suitability maps,
which indicate where and when dredging is possible without unacceptable environmental effects. The setup of the Interactive Dredge
Planning Tool and an illustrative showcase are presented here.
Eco-dynamic design for coastal protection
Many coastal ecosystems are known to contribute significantly to coastal protection and to provide many valuable ecosystem services. Yet,
the design of most present-day coastal protection structures ignores this ability of ecosystems or has not been optimized to facilitate
ecological functions. Both these structures and the ecosystem in which they are embedded can greatly profit from applying ecodynamic
design principles.
In the Singapore case, we assess how large-scale marine infrastructure projects, existing as well as envisaged, may be used to extend and
strengthen local ecosystems. This represents a paradigm shift from a technical functionality-based approach with ecosystem impact reduction
towards an ecosystem-based approach. Integrating the ecosystem functioning and its potential from the start into the design may offer
opportunities to strengthen (i.e. enhance functionality and/or diversity) Opportunities by using ecosystem connectivity or diversity) and extend
coastal ecosystems while at the same time achieving the infrastructural functionality targets. Moreover, as many ecosystems offer valuable
ecosystem services the economical benefits of such an approach may well exceed the extra costs.
Within the Building with Nature program, the following aspects are studied in relation to eco-dynamic design for coastal protection in tropical
environments.
Habitat requirements of the tropical ecosystems, coral reefs, seagrass meadows and mangrove forests. To stimulate the
development or to rehabilitate these ecosystems requires insight into the conditions under which they can develop and thrive. In this
wiki, the Building Block - Development of Mangroves as ecosystem engineer gives a concise overview of these requirements for
mangroves. Similar building blocks provide an overview for coral and seagrass. The knowledge page of opportunities offered by
ecosystem connectivity summarizes results of related scientific research on the establishment of mangroves and ecosystem services
they provide, and on integrated perspectives on tropical coastal ecosystems and ecosystem resilience.
Design pilot East Coast Park: Development of four conceptual designs and one detailed design, following the BwN steps and
tutorials: Conceptual eco-dynamic design tutorial and Detailed Building with Nature design tutorial. The Building Block - Perched
beaches is elaborated as part of the detailed design. The Tool - Visual Thinking resulted from an eco-engineering course organized
in Singapore. Visualization is the process of transferring a concept or design to an image on paper. This tool can be utilized
particularly during concept development, brainstorming sessions and work sessions focusing on the generation of conceptual
designs.
The Building Block - Biodiverse Hard substrates: Increasing urbanisation has resulted in extensive replacement of natural habitats by
man-made protective structures, for example an artificial seawall. Being vertically steep and structurally quite simple, this
compressed intertidal region typically does not represent a shoreline habitat that can support the kind of biodiversity expected in this
otherwise unique-,- land-sea environment. This building block shows how the limited small-scale habitat structure of seawalls around
Singapore may be engineered to enhance their biodiversity without bringing back diseases such as malaria. Understanding how to
improve the value of seawalls as surrogates of natural habitats is important for intertidal biodiversity conservation on modified
shorelines.
Lessons learned
Lessons learned
This section gives an overview of generic lessons learned so far from the Singapore sub-program. Project specific lessons learned can be
found in the various wiki-deliverables from this sub-program (also see the links above).
Physical processes
When planning to develop a prototype eco-dynamic design for coastal protection works, about 80% of the time is needed to obtain
the necessary insight into the functioning of the local environmental en administrative systems. The remaining time needs to be
reserved for the first design detailing phase.
When sufficient data on the physical system (e.g. water levels, bathymetric maps) are not readily available, a literature survey
combined with sensitivity analyses using numerical models may prove to be a useful approach to gaining insight into the local
physical system behaviour.
Spatial patterns in the occurrence of seagrass meadows, coral reefs and mangrove forest provide qualitative information on the
physical system’s state.
Any dredge plume dispersal study needs to take due account of residual current patterns at the relevant spatial and temporal scales
as they largely determine the fate and transport of suspended sediments.
Ecological processes
It is difficult, if not impossible, to translate ecological thresholds derived from monitoring and manipulative lab and field experiments to
universally applicable criteria, standards and restrictions for dredging operations, as the results of the experiments are species- and
location- specific.
For this reason it is also not possible to derive these threshold and criteria from literature or other projects.
Guidelines can be given on how site-specific ecological thresholds and criteria can be determined using manipulative laboratory
experiments, field experiments and/or monitoring campaigns.
Governance processes
Different countries have different habits and different procedures. What might work in one area, might not work in another setting.
Presenting courses, seminars on opportunities, if not readily perceived, can work positively in spreading the philosophy behind BwN.
Be aware that other countries might have other interests and priorities than sustainability.
References
References
Literature
Barbier, E., 2000. Valuing the environment as input: review of applications to mangrove-fishery linkages.Ecological Economics 35:
pp. 47-61.
Barbier, E.B., 2007. Valuing ecosystem services as productive inputs.Economic Policy 22: pp. 177-229.
Barbier EB, S.D. Hacker, C. Kennedy, E.W. Koch, A.C. Stier, B.R. Silliman, 2011. The value of estuarine and coastal ecosystem
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Images
Tropical waters
Seagrass meadows
Corals
Mangroves in General, Wikimedia Commons
Seagrass
Mangroves
Corals
Southeast Asia
Global sea surface temperature. From aquarius.nasa.gov.
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150 types of coral in Singapore
Dredging plume
Opportunities