Intertidal Wetlands – A Case Study

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					Ecosystems at Risk – Case Study 2 – Intertidal Wetlands
By Tenille Brown
Holy Spirit College Bellambi

             Intertidal Wetlands – A Case Study

Spatial patterns and dimensions of intertidal wetlands
Intertidal wetlands develop in coastal areas subject to periodic inundation by salty
water. They are the breeding grounds and habitats for a variety of wildlife. They also
protect the quality of coastal waters by diluting, filtering and settling sediments, excess
nutrients and pollutants.
Mangrove wetlands are found in the intertidal zone along tropical and subtropical
coastlines. Mangrove wetlands help to protect the coastline from erosion; reduce damage
from storms; trap sediments washed off the land; and provide breeding, nursery, and
feeding grounds for thousands of species of fish, invertebrate and plants.
In temperate areas, coastal wetlands usually contain salt marshes, in which salt-
tolerant sedges are the dominant vegetation type. These highly productive ecosystems
serve as nurseries and habitats for prawns and many other aquatic animals.
In many parts of the world, intertidal wetlands are under assault. The worst
destruction is taking place in Asia, especially in the Philippines, Thailand, Bangladesh,
Indonesia and Java. Large areas have been cleared for timber, fuel wood and woodchips;
to create aquaculture ponds for rasing fish and shellfish; and to extend agricultural land
and urban areas. The sediment contained in runoff has inundated some. Pesticides washed
off agricultural fields have been poisoned some wetlands.
This destruction is not limited to the countries of the developing world. The US, for
example, has lost half of its wetlands over the last 200 years. Wetland reclamation for
urban, industrial and recreational land uses accounts for much of this loss, as does the
damming of rivers and the use of wetlands as landfill sites. In Australia, the draining of
wetlands – particularly shallow swamps and marshes for agricultural, urban and
industrial development, and the construction of ports, flood-control and tourism-related
industries – has had an impact on native flora and fauna; 5% of Australia’s endangered
plant species come from wetland habitats. Outside the large metropolitan areas, most of
Australia’s mangrove wetlands remain relatively intact. It has been estimated that 50% of
the world’s wetlands have been destroyed since 1900.

A mangrove is a salt-tolerant plant or plant community that grows between the land and
the sea where the mud is regularly covered and uncovered by the ebb and flow of the tide.
They grow successfully on mud flats, which is a difficult environment because of the
high salinity and low oxygen. Some species have special roots, called
pneumatophores, projecting up out of the mud to get oxygen from the air and water.
The richest mangrove communities occur in areas where the water temperature is greater
that 24ºC in the warmest month and where annual rainfall exceeds 1250mm. They also
need protection from high-energy waves, which can erode the shore and prevent
seedlings from becoming established.
Worldwide, there are some 181,000km² of mangroves. Approximately 43% of the world’s
mangroves are located in just four countries: Indonesia (42,550km²), Brazil (13,400km²),

Ecosystems at Risk – Case Study 2 – Intertidal Wetlands
By Tenille Brown
Holy Spirit College Bellambi

Australia (11,500km²) and Nigeria (10,515km²). Management decisions taken in these
countries will have a significant effect on the global status of mangrove ecosystems in the
Being salt-tolerant allows mangroves to dominate in a saline environment free of
competition. The characteristics that enable mangroves to tolerate high levels of salinity
                       ~ The ability to secret salt. This occurs through special glands,
                          which are usually found on the leaves, where tiny white flecks of
                           salt are frequently visible.
                       ~ The ability to exclude salts. This is achieved by root-based cells
                          that prevent the larger salt ions from entering, and takes in the
                          smaller water molecules.
                       ~ The ability to store or concentrate salt. This is usually done in
                          the bark or older leaves, which are an ‘expendable’ part of the
                          mangrove plant. Eventually, the leaves and bark fall off, taking
                          the excess salt with them.
In addition, mangroves have a number of features that help to minimise water loss from
the plant. These include thick, waxy leaves or dense hairs that reduce transpiration.
Mangroves have adapted to the anoxic (oxygen-deficient) soil conditions by developing
alternative ways to obtain the oxygen necessary for root metabolism. These include:
                       ~ Pneumatophores. These are a special type of root. They grow
                         upwards from the main root system. They absorb oxygen from
                         the air at low tide via special tissue called lenticels. When the
                         roots are submerged in water, the pressure within the tissue falls
                         as the stored oxygen is used by the plant. As the root is exposed
                         at low tide, more air is drawn in through the lenticels.
                       ~ Stilt or prop roots. These are another type of aerial root. They
                         grow from the trunk and lower branches. These lenticel-covered
                         roots enable the mangrove to absorb oxygen, with the added
                         bonus of supporting the mangrove in unstable sediments.
Mangroves have also developed specialised forms of reproduction. In common with
many terrestrial plants, mangroves reproduce by producing flowers and relying on
pollination by bees and insects. Once pollinated, however, the seed remains on the parent
plant where it germinates and grows stems and roots before being dislodged. Once in the
water they travel horizontally. On reaching brackish water they turn vertically, making it
easier for them to lodge in the mud. Once lodged in the mud they quickly produce
additional roots and begin to grow.

The Ramsar Convention
The Ramsar convention was initiated at a meeting in the small Iranian town of Ramsar in
1971. The convention provides a framework for international corporation in the
conservation and sustainable use of wetlands. Ramsar was the first of the modern
global treaties dedicated to the conservation of a particular ecosystem.

Ecosystems at Risk – Case Study 2 – Intertidal Wetlands
By Tenille Brown
Holy Spirit College Bellambi

The convention’s mission is the conservation and wise use of wetlands by national action
and international-corporation as a means to achieving sustainable development
throughout the world.
The obligations of countries party to the agreement are:
                      ~ The nomination of suitable sites as ‘wetlands of international
                         importance’ and thereafter ensuring that they are managed in
                         ways that maintain their ecological character.
                      ~ The formulation and implementation of national land use
                        planning that includes wetland conservation considerations and,
                        promotes the wise use of wetlands within their territory.
                      ~ The development of national systems of wetland reserves,
                         facilitating the exchange of data and publications, and the
                         promotion of training in wetlands research and management.
                      ~ To cooperate with other countries in promoting the wise use of
                         wetlands where wetlands and their resources.

Salt Marshes
Along intertidal shores in middle and high latitudes throughout the world, salt marshes
replace the mangrove swamps as the dominant type of coastal wetland.
Salt marshes are extremely productive ecosystems, but they are not very diverse.
Diversity within the marsh tends to increase with distance from the zone of inundation.
The global extent of salt marshes is still unknown. At 8,000km², Europe’s Wadden Sea
salt marshes are the world’s largest. In North America some of the most extensive salt
marshes lie along the 800km shoreline of the Alaskan Yukon-Kuskokwim Delta, one of
the largest deltas in the world. Over time, large areas of salt marsh have been drained for
agriculture and urban land uses.

The intertidal wetlands of Sydney’s Bicentennial Park
Sydney’s Bicentennial Park wetlands at Homebush Bay are located approximately
12km west of Sydney’s CBD, on the southern bank of the Parramatta River. The
wetlands cover an area of 58ha. The size, shape and continuity of the wetlands have
been defined by the activities of people. The northern boundary of the wetlands is
determined by the presence of bund walls, built during the 1950s to facilitate the
reclamation of the wetlands. On the eastern side, Powells Creek has been straightened to
maximise storm-water discharge and facilitate land reclamation. On the western side of
the wetlands lies a heavy traffic roadway. On the southern side of the former landfill site
has been transformed into formal parkland: Bicentennial Park.
Bicentennial Park’s 58ha of wetland consist of approximately:
                      ~ 40ha of mangrove forest.
                      ~ 10ha of open, shallow water – the waterbird refuge.
                      ~ 8ha of salt marsh.
Although the original wetlands of Homebush Bay have been greatly reduced in extent
and fragmented by a variety of industrial land uses, strategies have been developed to
re-establish ecological links to nearby sites. The area’s land use is now defined as nature
conservation, passive recreation and research.

Ecosystems at Risk – Case Study 2 – Intertidal Wetlands
By Tenille Brown
Holy Spirit College Bellambi

Biophysical interactions – Atmosphere
The interactions of the atmosphere with other spheres in the intertidal wetlands include,
the hydrosphere’s contribution via high humidity levels; the lithosphere’s soil profile
contributing to the creation of gasses; and the biosphere’s contribution of bacteria that are
integral to the processes of hydrogen sulphide gas creation in the soils of the mangrove

Biophysical interactions – Hydrosphere
The interactions of the hydrosphere with other components of the biophysical
environment in intertidal wetlands include, the atmosphere’s contribution to gases that
are found in water, especially high dissolved oxygen levels; the lithosphere’s soil
movements, which contribute to the often high turbidity present in the water coming into
the wetland; and the biosphere’s contribution of organic material, which adds to the store
of nutrients.

Biophysical interactions – Lithosphere
The interactions of the lithosphere with the other components of the biophysical
environment in intertidal wetlands include, the atmosphere’s contribution to rainfall,
which can alter the salinity level of the wetland soil; the hydrosphere’s contribution to
soil moisture, especially in the mangroves where it is necessary for plant growth; and the
biosphere’s organisms, such as mangrove air-breathing snails, which recycle nutrients.

Biophysical interactions – Biosphere
The interactions of the biosphere with other components of the biophysical environment
in intertidal wetlands include, the atmosphere’s contribution to the climatic conditions
required to support intertidal wetlands, the hydrosphere’s contribution to the slightly
alkaline conditions necessary for some plants and animals; and the lithosphere’s
waterlogged characteristics, which are necessary for the distinctive flora and fauna of the
intertidal wetlands.
A range of plant species is found in the Bicentennial Park wetlands. Over 140 species of
bird have been recorded in the park, including migratory and endangered species.

Biophysical interactions – Types of interaction – The dynamics of weather and
The distribution of mangrove and salt marsh species is largely determined by
temperature and rainfall. The natural stress of high rainfall can create the necessary
conditions for the rejuvenation, recolonisation and spread of intertidal wetlands.
The migratory and sedentary terrestrial fauna of intertidal wetlands is also affected by
variations in rainfall and other factors that determine the availability of fresh water.

Biophysical interactions – Types of interaction – Geomorphological and
hydrological processes
The Geomorphological and hydrological processes combine to create intertidal wetlands.
The deposition of 8m of silt in the lower reaches of the Parramatta River provided the
conditions necessary for the development of intertidal wetlands.

Ecosystems at Risk – Case Study 2 – Intertidal Wetlands
By Tenille Brown
Holy Spirit College Bellambi

Changes in geomorphological and hydrological processes can result in ecosystems
being placed at risk. The rate of deposition is increased to a harmful level if soils are left
exposed, especially during periods of heavy rainfall. Increased levels of turbidity can lead
to deterioration in the health of the wetlands. In the case of Bicentennial Park wetlands,
the straightening of Powells Creek directed a large proportion of the runoff away from
the mangrove forests. On the other hand, it significantly reduced the natural deposition of
soil on the floor of the mangrove forest. Overall, this ‘shielding effect’ can have a
detrimental impact on the mangroves as it interferes with the processes of intertidal
wetland succession.

Biophysical interactions – Types of interaction – Geomorphological and
hydrological processes – Rising Sea level
In some cases, the present distribution of plant species owes more to past environmental
conditions than it does to the conditions that exist today. For example the distribution of
mangrove and associated plant species in northeastern Australia has been attributed to,
among other factors, the land connections with Southeast Asia during past changes in sae

Biophysical interactions – Types of interaction – Geomorphological and
hydrological processes – Weathering
The intertidal wetland is where large amounts of weathered material accumulate. This
alluvial material, together with the large amount of organic material produced by the
mangrove vegetation, results in the formation of soils that are nutrient rich. This
organic matter is transferred to the soil, where it provides valuable nutrients and provides
a buffer against stress events.

Biophysical interactions – Types of interaction – Geomorphological and
hydrological processes – Erosion
The location of intertidal wetlands is sheltered embayments makes them places
characterised by an accumulation of sediments rather than erosion. The role of wetlands
as flood mitigators means that they are able to absorb floodwaters and release them
slowly to minimise erosion. Some erosion may occur during storm events, with the
erosive power of the storm over-whelming the protective capacity of the vegetation. The
highly saline nature of the wetlands, especially salt marshes, means that the bonds
between soil particles are vulnerable to breakage. This makes the soil susceptible to
erosion resulting from physical pressures created by wind, water or trampling.

Biophysical interactions – Types of interaction – Geomorphological and
hydrological processes – Transport and deposition
The sediment deposited in coastal wetlands tends to be very fine. As the river
approaches the coast its velocity and carrying capacity declines. Often only the finest
sediment makes it to the estuarine environment.
The deposition of sediment in the intertidal wetlands ultimately results in the creation of
new land.

Ecosystems at Risk – Case Study 2 – Intertidal Wetlands
By Tenille Brown
Holy Spirit College Bellambi

The straightening of Powells Creek changed because the pattern of sediment transport
and the deposition in the vicinity of the Bicentennial Park wetlands. The dominance of
hard surfaces within the catchment are presence of drainage infrastructure greatly
increases the sped at which runoff is expelled from the catchment. As a result, less silt is
deposited in the mangroves and more on the mud flats of Homebush Bay. The long-term
outcome of this change is unknown but may include the partial ‘infilling’ of Homebush

Biophysical interactions – Types of interaction – Geomorphological and
hydrological processes – Soil formation
The specific type of soil found in intertidal wetlands reflects the nature of the parent
material from which it is derived and the topography, climate and vegetation found in the
The soils of mangroves are often quite unstable; they are constantly shifted and sorted
by water movements. Mangroves cope with this by having shallow, widespread root

Biogeographical processes
Intertidal wetlands provide an excellent example of invasion, modification and
succession. There is a succession both within and between each of the seagrass,
mangrove and salt marsh of the intertidal wetland.
The diversity and number of species using the intertidal area change. The succession of
intertidal areas to one of the later stages of the salt marsh is validated by the fact that
there is greater species diversity, nutrient recycling and niche specialisation in this area.
Because of its high level of nutrient recycling, salt marshes are described as one of the
most productive ecosystems on earth.

Adjustments to natural stress and the nature and rate of change – Salinity
Intertidal wetlands are located in parts of the coastal environment that receive both
fresh and salt water. They must, therefore, be able to survive extreme conditions. The
saline water is very difficult condition for plants to survive in. The grey mangrove is
able to do this because its rot structure allows salt to be excluded.
The plants of the salt marsh must be able to survive within a range of salinity levels in
both the water and soil. Plants on lower slopes of the marsh must be able to cope with
saline water. This area is inundated during higher tides. As a result, however, it is
vulnerable to the stress factors associated with pollution because it can accumulate
pollutants along with the water.

Adjustments to natural stress and the nature and rate of change – Tidal movements
Intertidal wetlands are an example of an ecosystem that the stress-dependent organisms
and processes. The change and stress caused by tidal movement are significant and the
intertidal wetland has very specific responses.
The grey mangrove has a root system that includes pneumatophores. However, this
natural response to the stress of tidal inundation can fail if the magnitude or frequency of
inundation is changed by increased runoff or altered drainage, and the roots are

Ecosystems at Risk – Case Study 2 – Intertidal Wetlands
By Tenille Brown
Holy Spirit College Bellambi

submerged for too long. The mangrove tree can be pushed beyond its threshold level if
the water quality is changed and substances such as oil cover the root’s lenticels because
this impedes their ability to take in air.
The locations of intertidal wetlands mean that even healthy ecosystems are vulnerable to
changes within the catchment. Vulnerable components include, but are not limited to,
humidity, phosphate concentrations, soil pH and the existence of a monoculture.
It must be remembered that the intensity and duration of stress is important when
assessing its impact on the ecosystem. The intertidal wetland is both aquatic and
terrestrial systems. The sensitive indicators – species composition and the demographics
of the aquatic system – must be considered. Oysters and molluscs, for example, have
often been used as indicator species, with any decline in their numbers being an indicator
that the ecosystem is under stress. Nutrient levels are an important indicator of ecosystem
resilience. Decline in primary productivity may be reflected in a decline in nutrients.

Human impacts positive and negative – Atmosphere
Human modification of the atmosphere in the intertidal wetlands includes the changing of
wind patterns caused by the inappropriate location and design of buildings adjacent to the
wetlands and walkways within them. The implementation of policies that regulate
construction near a wetland is a positive step in the management of this problem.
The construction of walkways must be carefully managed to avoid altering wind patterns
within the wetlands. The use of non-linear walkways minimises the disruption to the
canopy and avoids the wind-channelling effects associated with linear walkways.
The high level of humidity found within wetlands is an example of the interaction
between the atmosphere and hydrosphere. Any alteration to water flows will affect
humidity levels. The changes to drainage patterns brought about by the rerouting of
Powells Creek in the 1950s had a detrimental impact on the Bicentennial Park wetlands.

Human impacts both positive and negative – Hydrosphere
Urban and industrial land uses within the Powells Creek catchment have contributed to
increased levels of turbidity. Toxic chemicals – the accumulated legacy of decades of
industrial activity in the area surrounding Bicentennial Park – also pose a threat to the
health of the ecosystem.
Oil spills from vessels using Sydney Harbour are another constant threat. Oil can
smother the grey mangrove’s pneumatophores, denying the plant oxygen essential
to its survival.
Because the Powells Creek catchment has been extensively modified by the activities of
people, it is unlikely that the creek transports natural levels of organic material into the
Bicentennial Park’s intertidal wetlands. Increased concentrations of phosphates –
derived from detergents and garden fertilisers – have been identified as a concern.

Human impacts both positive and negative – Lithosphere
The construction of bund walls has changed hydrology of the site by modifying
(reducing and redirecting) the flow of water. The reduction in flow has affected soil
moisture in the mangroves. This has the potential to elevate levels of acid sulphate,

Ecosystems at Risk – Case Study 2 – Intertidal Wetlands
By Tenille Brown
Holy Spirit College Bellambi

damaging the health of the mangroves and adversely affecting the decomposer organisms
that recycle minerals essential to the functioning of the ecosystem.

Human impacts both positive and negative – Biosphere
The widespread death of marine organisms within these wetlands has been associated
with the dumping of toxic chemicals in the catchment’s waterways.
The alteration of the lithosphere, especially the construction of rock and dirt bund walls,
not only altered the pattern of tidal flow it introduced weeds into the intertidal wetland

Human impacts positive and negative – Human modification of intertidal wetland
The use of intertidal wetland ecosystems by humans can be described by degrees of
modification to natural vegetation.
                      ~ Removal. Areas of intertidal wetlands have been cleared to
                         accommodate residential and industrial land uses, transport
                         facilities and waste-disposal sites.
                      ~ Replacement. Areas of intertidal vegetation have been replaced
                         with a managed system of pasture. Homebush Bay was the site of
                         the State Abattoir for most of the 20th century.
                      ~ Utilisation. Salt marshes were modified and exploited as salt
                          pans in the early 1880s, and for recreation in contemporary times
                      ~ Conservation. The remnant natural vegetation of intertidal
                          wetland ecosystem has been preserved for conservation and
                          scientific purposes. The deliberate modification of natural
                          processes has been minimised, but there may be indirect impacts
                          from the land use activities on adjacent or nearby sites.
Known human disturbances to the energy and nutrient cycles of the intertidal
wetland include the introduction of feral animals, such as foxes and cats. Carnivorous
species are not common natural intertidal wetlands and thus severely disrupt the food and
nutrient cycles by significantly affecting bird populations.
Other charges to the natural processes of the intertidal wetlands include the impact of
chemicals and altered pH on the organisms and bacteria responsible for nitrogen fixing
and recycling, as well as the strengthening of the bonds between soil particles.

Human impacts positive and negative – Positive impacts – Exclusion
Those responsible for the management of wetland areas often facilitate public access to a
small, designated area while restricting access to other areas. In the Bicentennial Park
wetlands, access has been controlled by the provision of defined walkways and

Human impacts positive and negative – Positive impacts – Education
In the past, intertidal wetlands have often been regarded as smelly, mosquito-ridden
wastelands. Education campaigns have helped to change public perceptions and

Ecosystems at Risk – Case Study 2 – Intertidal Wetlands
By Tenille Brown
Holy Spirit College Bellambi

create public support for the protection of these highly productive yet threatened
Because intertidal wetlands are located in the lower reaches of catchments, education
programs need to embrace a total catchment management approach. This is needed
to prevent potentially harmful human activities occurring elsewhere in the catchment,
from impacting on the wetland ecosystem.
Bicentennial Park’s education program includes guided tours for the general public,
school visits and field studies centre, media liaison, conference presentations,
interpretive signage, publications and fact sheets.

Human impacts positive and negative – Positive impacts – Action
Too little is known about the intertidal wetland ecosystem to successfully reinstate all
natural conditions. The management of the Bicentennial Park wetlands has focused on
the rehabilitation of the site and the removal of some of the human-induced stress factors.
For example, some bund walls have been removed to restore tidal flushings.

Human impacts positive and negative – Positive impacts – Design
Design interventions have proved successful in minimising sources of environmental
stress. Hydrologists, for example, have designed structures that maximise tidal flows and
maintain the health of the ecosystem.

Human impacts positive and negative – Positive impacts – Legislation
Regulatory frameworks impacting on the management of wetlands include legislation
dealing with threatened species, river foreshores, soil conservation and catchment
The regulations governing the Bicentennial Park wetlands are contained in the
Bicentennial Park Act (1987).

Why protect intertidal wetland ecosystems – Maintaining genetic diversity
Although we know that each of the organisms plays an important role in nutrient
recycling, the exact nature of this role, and the interactions between species, is still not
fully understood. What is known is that the genetic diversity is a result of convergent
evolution: a process brining together many different plant families, all of which have a
similar response to the prevailing environmental conditions.
The animals that use the wetlands are, for the most part, visitors from other ecosystems.
Therefore, the maintenance of wetland ecosystems is inextricably linked to that of
many other ecosystems. From a human point of view, we must acknowledge that
intertidal wetlands provide the filtered water, gases, fish and marine life on which we all
depend. What is still to be fully realised is the medical and scientific value of this

Why protect intertidal wetland ecosystems – Utility value
The wetlands have been used in Australia’s past (and are still being used in many
developing countries) for the productions of wood for construction and heating purposes

Ecosystems at Risk – Case Study 2 – Intertidal Wetlands
By Tenille Brown
Holy Spirit College Bellambi

and the harvesting of marine life. Once these resources have been used, the land is often
reclaimed for agricultural, industrial and residential purposes.
The land of the intertidal wetlands of Homebush Bay have been used in the past for salt
extraction, chemical industries, public utilities such as radio towers and gas lines, and as
a rubbish dump.

Why protect intertidal wetland ecosystems – Intrinsic value
The intrinsic value of wetlands has often been ignored in the human-orientated
exploitation of these ecosystems for economic returns. Today, wetlands such as those at
Homebush Bay are being protected for their intrinsic value and uses are limited to those
that do not exploit or disrupt the components of the ecosystem.

Why protect intertidal wetland ecosystems – Heritage values
Natural areas, including wetlands, are an important part of our natural heritage and can
provide an insight into the ways people lived in the past especially their historical or
cultural significance to past communities. The wetlands of Bicentennial Park have been
acknowledged as such and are officially recognised as part of the National Estate.

Why protect intertidal wetland ecosystems – The need to allow processes of
selection. Evolution and change to continue
The area protected must be large enough to allow evolutionary processes to operate as
they would in nature.
Although Bicentennial Park preserved the largest standing mangrove stand on the
Parramatta River, it is still to be seen whether its size and linkages, modified prior to
management, will be large enough to support natural change.

Traditional and contemporary management practices – Identify management goals
and objectives
The traditional objectives for the management of the Homebush Bay site were built
around the sustainable use of wetland resources for food, shelter and tools. The
Europeans’ use of the wetlands, until relatively recent times, was consistent with the
objective of resource exploitation for economic gain. From the late 1700s to mid-1900s
the intertidal wetlands of Sydney were cleared and the land reclaimed so that it could be
used for agricultural, industrial and residential purposes. For much of the 1900s the
wetlands of Homebush Bay were used for industry and waste disposal. Today the
management goals and objectives for the Bicentennial Park wetlands focus on
preservation of the site recreation, education and conservation purposes.

Traditional and contemporary management practices – Define the management unit
and boundaries
The ‘management unit’ for the intertidal wetland is difficult to define because of the large
number of stakeholders – especially when you take into account the nature and
movement of some on the integral components of the wetland, such as water.
The boundaries for the management of these wetlands are also difficult to establish
because they can be based on ecosystem, lower-catchment or full-catchment guidelines.

Ecosystems at Risk – Case Study 2 – Intertidal Wetlands
By Tenille Brown
Holy Spirit College Bellambi

The wider the boundary, the greater the control of the components of the wetland; the
greater the demand on economic and human resources.

Traditional and contemporary management practices – Develop and implement
management plans
Care has been taken to develop management plans that are both realistic and flexible.
This enables these plans to accommodate scientific and technological advances, changing
social and political attitudes and variations in the level of funding. Thus, they can also
take into account the experience and education of those responsible for managing
Management plans also need to be consistent with Australia’s international obligations as
defined by various international treaties and conventions. Plan should also reflect the
various legislative requirements enacted by the Federal Government and the various state
and territory parliaments.

Traditional and contemporary management practices – Select and utilise ecosystem
management tools and technologies
Indigenous Australians managed wetlands in ways that acknowledged the unique nature
of the ecosystem. They used the wetlands as a source of food and, in doing so, took only
what was needed to meet their immediate needs.
Contemporary approaches to the management of intertidal wetlands have benefited from
a growing body of international research. This knowledge has been applied to the
management of particular wetland ecosystems.

Traditional and contemporary management practices – Clearly identify ecological
constraints or limitations
Despite the growing body of international research, our knowledge of intertidal
wetland ecosystems remains limited. This is perhaps understandable given our concern
for the survival of wetlands has only recently been rekindled. Indigenous Australians had
a close affiliation with, and knowledge of, this area, but has been largely lost. Today, too
little is known of the ecological constraints or limitations of the ecosystem.

Traditional and contemporary management practices – Involve stakeholders in
decision-making processes
Effective management demands that adjacent landowners, resource users and other
institutions or agencies that have an interest in, or jurisdiction over, the site should be
involved in decision-making processes.
The location of the intertidal wetlands means that it is vulnerable to the disruptions
caused by the activities of people throughout the surrounding catchment. The Homebush
Bay wetland lies at the heart of a vast metropolitan area of more than 40,000 people.

Traditional and contemporary management practices – Be ecologically sustainable
To be effective, the management of intertidal wetlands should conform to
ecologically sustainable ideals.

Ecosystems at Risk – Case Study 2 – Intertidal Wetlands
By Tenille Brown
Holy Spirit College Bellambi

Increasing awareness of the role of wetlands in the life cycle of marine and terrestrial
organisms has led to a recognition that intertidal wetlands need to me managed in an
ecologically sustainable manner.
The strategies used to minimise the human-induced impacts on wetlands focus on the
health of the particular intertidal wetland ecosystem: its community of pants and animals.
Decision-making processes effectively integrate both long- and short-term economic,
environmental, social and equity considerations through their flexibility.
Where there is a threat or serious or irreversible environmental damage, a lack of full
scientific certainty should never be used as an excuse for postponing measures that
prevent or minimise environmental degradation. The management of the Bicentennial
Park wetlands features a ‘precautionary approach’ to environmental management.
Practices such as unrestricted public access, fishing, boating and the collecting of flora
and fauna, which may prove detrimental to the long-term health of the wetland
ecosystem, are thus subject to bans and restrictions.
Increased environmental monitoring and the sharing of data have increased our
understanding of international processes affecting intertidal wetlands, including ocean
currents, global warming and bird migrations. Global processes significant to the
Bicentennial Park site include the migration of birds from the wetlands of China and
Scarce resources such as wilderness and endangered species need to be conserved.
While some aspects of wetland ecosystems are resilient and able to cope with change (for
example the potential for a mangrove area to re-establish a canopy and subsequently
some of its microclimate conditions), other areas are not as resilient (for example the re-
establishment of bonds between the particles of the soil in salt marshes).
Strategies that minimise human-induced change and allow for natural evolutionary
processes to proceed need to be implemented. Only then will long-term health of
ecosystems be secured.
Ultimately, all wetland sites will benefit from greater interaction between the public and
those responsible for their management.
Any proposed development must be assessed in terms of its potential impact on the
wetlands – Environmental Impact Statements (EIS).