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Wetlands
Bioregion: All Terrestrial
Relationships with the Landscape
The Natural Capital of Wetlands
Management Themes
Biodiversity Condition
International and National Policy Setting
Management Responses
Tables and Charts for the Wetlands
Relationships with the Landscape
Wetlands are a unique part of Victoria’s landscape, supporting distinctive communities of plants and animals. They range widely in character including such diverse areas as alpine bogs, floodplain billabongs, River Red Gum forests, Coastal Tea-tree swamps, large open lakes, shallow seasonal swamps, estuaries, intertidal mudflats and inland hypersaline lakes.Victoria’s 13 114 wetlands now occupy 535 453 hectares or two per cent of the State and are distributed unevenly across the landscape. Not surprisingly, the greatest concentrations of wetlands are in the lowland plains and in the Victorian Embayments marine bioregion. Wetlands are much less common in bioregions of higher relief, for example the Victorian Alps, and in the dunefields of the Victorian Mallee.
Wetlands are difficult to define and classify. The definition used by the Convention on Wetlands of International Importance, also known as the Ramsar Convention, is very broad; it includes natural lakes, swamps and estuaries, rivers and streams, shallow marine areas (including beaches and rocky shores), and artificial wetlands such as reservoirs, sewage farms, irrigated agricultural land and farm dams. This section focuses primarily on natural inland lakes, swamps, estuaries and intertidal mudflats. It does not cover artificial wetlands. Instream habitats and bays, inlets and estuaries are dealt with under different sections.
The wetlands discussed in this section are those naturally occurring depressions or floodplains which are covered temporarily or permanently by fresh, brackish or saline water.
They are classified into six categories.
- Freshwater meadows — shallow freshwater wetlands holding water for less than four months of the year.
- Shallow freshwater marshes — shallow freshwater wetlands that usually dry out in mid-summer and refill with the onset of winter rains.
- Deep freshwater marshes — deep freshwater wetlands that remain flooded for most of the year but may dry out occasionally.
- Permanent open freshwater wetlands — deep freshwater wetlands that hold water permanently.
- Semi-permanent saline wetlands — saline wetlands flooded for less than eight months of the year, including salt pans and salt meadows.
- Permanent saline wetlands — saline wetlands that rarely dry out, including tidal areas and saline inland lakes.
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The Natural Capital of Wetlands
Wetland ecosystems are highly productive and characterised by a high rate of nutrient recycling. Nutrients enter wetlands from their catchments and are trapped and stored in wetland sediments. Nutrients in sediments, those captured by microscopic phytoplankton in the water column or those released from decaying wetland vegetation, form the basis of the nutrient cycle in wetlands. Organic plant matter broken down into detritus by bacteria and fungi is consumed by organisms such as snails, crustaceans, insect larvae and worms. Phytoplankton are eaten by zooplankton and these and other invertebrates form the diet of the larger vertebrates such as fish, frogs, reptiles and birds.Wetland flora is distinctive and varied. It typically includes several different plant forms including algae; floating plants such as the tiny fern Azolla and duckweed Lemna; benthic plants which are attached to the bottom but grow submerged such as seagrasses and pond weeds; emergent macrophytes such as reeds, rushes, sedges, herbs, grasses, trees and shrubs. Trees and shrubs characteristic of wetlands include paperbark and tea-tree species, Lignum, glasswort species, River Red Gum, Black Box and White Mangrove.
The distinct communities of wetland species that are a feature of different wetland types in different regions are the result of individual species’ responses to a suite of factors such as climate, altitude, geomorphology, soil type, water regime, nutrient status and water chemistry. Examples of distinctive wetland communities include sphagnum bogs in alpine regions, coastal salt marshes dominated by species of glassworts, River Red Gum forests and reed swamps dominated by the Common Reed or Cumbungi, and seagrass beds typical of estuaries, inlets and bays. Plants in wetlands respond to factors such as water depth, period of inundation and light penetration, resulting in vegetation zones within many wetlands. Some wetlands are densely vegetated while others have areas of open water or are devoid of larger plants except around their margins.
Aquatic invertebrates are a notable component of the wetland biota. In many inland temporary wetlands the cycle of drying and refilling is important in driving pulses of invertebrate productivity. During dry periods, organic matter accumulates in wetlands. When these flood, the detritus quickly gives rise to very high numbers of invertebrates, which are an important factor in stimulating breeding in many fish and waterbird species.
More than 100 species of waterbirds use Victorian wetlands. Intertidal habitats, such as those in Corner Inlet, provide essential habitat for large numbers of migratory waders. Wetlands are important breeding areas for waterbirds. Some colonially nesting species, such as terns, ibis, pelicans, spoonbills, egrets and cormorants, form breeding colonies when conditions are right at certain wetlands. Appropriate management and conservation of these key wetlands and also the shallow seasonal wetlands used for feeding at breeding time are critical to the breeding success of these species. The large open permanent saline lakes in the Colac area are important sites for waterfowl to take refuge in during moulting when they are temporarily flightless.
Reptiles, amphibians and fish play a major role in wetland food webs. Estuaries and mangrove areas are particularly important habitats for the juveniles of many commercial fish species.
There has been a dramatic reduction in natural wetland area since European settlement. Thirty-seven per cent of Victoria’s wetland area has been lost, primarily as a result of drainage. The greatest losses of original wetland area have been in the freshwater meadow (43 per cent), shallow freshwater marsh (60 per cent) and deep freshwater marsh (70 per cent) categories. The majority of decline has been on private land. The map above illustrates the extent of wetlands before European settlement. Of particular note is the original extent of Koo Wee Rup Swamp to the north of Western Port, which has since been almost totally drained. Wetland loss has also been significant in the Riverina and the south-west of the State.
The number of artificial wetlands has increased since European settlement, but the vast majority of these are farm dams of less than one hectare in area. Artificial wetlands provide habitat for some wetland flora and fauna species but are often of low ecological value as they have unnatural water regimes and lack the habitat diversity of natural wetlands. Few artificial wetlands have been constructed with the purpose of enhancing biodiversity values.
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Management Themes
Wetlands are valuable to the Victorian community for conservation, aesthetic and economic reasons. Their value and proper functioning as flora and fauna habitat is important not only for biodiversity conservation but also as the basis for many of their other values. Healthy functioning wetlands maintain water quality by trapping sediments and utilising and storing nutrients. They also assist in flood protection by storing floodwater and releasing it slowly. Many commercial and recreational fish species depend on wetlands for at least some part of their life cycle. Forestry and recreation are significant economic uses of the River Red Gum forests along the Murray River. Wetlands are important to agriculture in supporting waterbirds that feed on insect pests, in providing sources of water for stock and in providing opportunities for grazing and for aquaculture.Recreational uses of wetlands are also highly valued by the community. Activities such as recreational fishing, boating, swimming, duck hunting, birdwatching and bushwalking attract many people to wetlands and, in places such as the Gippsland Lakes, provide the basis for tourist industries. Wetlands are valuable as areas for study and education and as sites of archaeological and cultural significance.
They also contribute to the scenic quality of the landscape throughout Victoria.
Three-quarters of the wetland area in Victoria is on public land but this is only 20 per cent of the total number of wetlands. Wetlands on public land are generally larger and more permanent while those on private land tend to be smaller and less permanent. Many wetlands on public land are managed to protect biodiversity as part of the protected area network; some are managed for multiple uses, including forestry (for example, some River Red Gum forests along the Murray); and some as part of irrigation water supply and wastewater disposal systems or for recreation. Wetlands on private land are most often managed within the context of broader agricultural land use.
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Biodiversity Condition
The impact of European settlement on Victoria’s wetlands has been severe. Some wetlands have been totally lost and many that remain have been affected by one or more degrading processes. The main process contributing to wetland loss and degradation in Victoria has been total or partial drainage. Thirty-seven per cent of the State’s natural wetland area has been lost in this way. About half of this consists of wetlands which were totally destroyed, while the other half of the lost area involves the reduction in size of many wetlands. An additional 30 per cent of the original area of wetland in Victoria has been degraded through partial drainage or changes in water regime. Although the rate has slowed since early this century, wetland drainage still continues. Over 90 per cent of the area lost has been on private land. Areas most affected by drainage are south-western Victoria and the irrigation areas around Kerang and Shepparton.Another critical issue in wetland conservation is the maintenance of appropriate water regimes. Changes in water regime can drastically change wetland appearance and functioning, disrupting natural productivity cycles, causing changes in vegetation, including loss of existing species, and changes in habitat. Altered water regimes have many causes including wetland drainage, lowered or raised water tables, construction of levee banks, the use of wetlands for water storage or wastewater disposal associated with irrigation and drainage schemes, and urban development. Altered water regimes are responsible for a significant proportion of wetland change. Almost all wetlands with less permanent water regimes are on private land, while about one-third with more permanent water regimes are on public land. A significant factor affecting the water regime of floodplain wetlands is river regulation, which has reduced the exchange of nutrients and organic matter between rivers and floodplains and led to changes in the flooding regime, the community structure of billabongs, fish movement and fish and waterbird recruitment.
The extent of wetland change due to increasing salinity is less significant at a state-wide level than the effects of drainage and changed water regimes, but is still important in some Victorian bioregions. Wetlands may become saline due to rising water tables bringing saline water to the surface or by the disposal of saline irrigation tailwaters. Native vegetation clearing and irrigation practices have contributed to salinity problems in many agricultural areas of Victoria and many wetlands in these areas, particularly in north central Victoria, are affected by salinisation. Some coastal wetlands, such as the Gippsland Lakes, are becoming more saline because estuaries are now open to the sea more often than they were prior to European settlement.
Grazing livestock in wetlands often contributes to degradation through such effects as soil compaction, increased nutrient input, changes in turbidity, spread of weeds, selective grazing and trampling of indigenous wetland vegetation and erosion. However, light grazing can sometimes be a suitable tool in controlling weeds or reducing fire hazard in wetlands. Grazing in wetlands occurs mainly on private land but also on some public land. The strategic management of stocking rates, duration and timing of grazing and type of stock can lessen the impact of grazing on wetland ecosystems.
Runoff with an increased nutrient load from rural and urban catchments may result in algal blooms and eutrophication in wetlands which may then be closed to recreation in summer. Other issues affecting wetlands include pollution, sedimentation, dredging to improve navigation in coastal wetlands and land filling (usually in conjunction with urban expansion). Wetland pest plants, such as Spartina, and pest animals, such as European Carp, can be very invasive and difficult to control once they have entered wetland systems. Issues associated with recreational use include the poisoning of waterbirds from ingesting spent lead shot discharged by duck hunters and stocking wetlands with introduced fish to support recreational fishing.
At least nine potentially threatening processes listed under the Flora and Fauna Guarantee Act 1988 affect wetlands. As a result of the threats to wetland ecosystems, many species that depend on wetlands are now threatened with extinction. Five wetland communities have been listed under the Act.
Fifteen Action Statements under the Flora and Fauna Guarantee Act 1988 have been prepared for species and potentially threatening processes associated with wetlands.
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International and National Policy Setting
Australia is a signatory to the Ramsar Convention, which imposes obligations to include wetland conservation considerations in land use planning and promote the wise use of all wetlands; to list at least one site of international significance and maintain the ecological character of listed sites; to establish nature reserves based on wetlands; and to promote training in the fields of wetland research and management. Victoria, together with the other States and Territories, administers the obligations of the Convention in relation to its jurisdiction in partnership with the Commonwealth. Victoria has ten sites of international significance listed on the Ramsar Convention and has, to date, identified 161 wetlands for inclusion in A Directory of Important Wetlands in Australia (Second Edition).Australia is also party to the Japan-Australia Migratory Bird Agreement (JAMBA) and the China-Australia Migratory Bird Agreement (CAMBA). These bilateral agreements, also administered in partnership with other States and Territories and the Commonwealth, call for the protection of the habitats of the migratory bird species listed in the agreements. Many of these species frequent Victorian wetlands, most notably migratory waders. Seven of the 30 most important Australian sites for migratory waders are in Victoria. In 1996, a program was launched in response to the need for international action to protect migratory shorebirds along the East Asian–Australasian Flyway. The East Asian–Australasian Shorebird Reserve Network links wetlands that are internationally important for shorebirds. To date, 19 sites have joined the Network from eight countries. The Shorebird Reserve Network highlights the importance of wetland areas for shorebirds and promotes activities for their conservation. Victoria has nominated Corner Inlet to the network. The Commonwealth Government released a Wetlands Policy in January 1997. A key strategy is for the Commonwealth to work in partnership with State and Territory governments to promote wetlands conservation. Mechanisms for this include the development of complementary wetland policies, ongoing identification of nationally important wetlands, strengthening links between the Commonwealth and States on shared wetlands issues, and instituting formal partnership agreements in relation to specific wetland issues.
Several Victorian wetlands are included on the Register of the National Estate. The Commonwealth is required to consider the effects on listed areas of proposals for which the Commonwealth has a decision-making role and not to take action that adversely affects a listed site unless there is no feasible or prudent alternative.
The Murray-Darling Basin Ministerial Council is developing a Floodplain Wetlands Management Strategy which will focus on issues in the management of floodplain wetlands in the basin, including those along the northern flowing rivers north of the Great Dividing Range in Victoria.
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Management Responses
The vision for wetlands is to protect Victoria’s wetland biodiversity by promoting the conservation and wise use of all wetlands. The principal outcomes sought are:- maximum retention and restoration of existing wetlands, as far as practicable;
- viable wild populations of native wetland-dependent flora, fauna and ecological communities;
- a representative selection of Victoria’s wetland environments afforded protection in the State’s protected area network of parks and reserves;
- a strong partnership between owners of wetlands on private land, catchment and coastal authorities and local and State government agencies that encourages wetland owners to use wetlands wisely and sustainably, restore degraded wetlands and protect wetland biodiversity;
- an increased awareness and appreciation of wetlands by the community leading to a higher level of active participation in wetland conservation and monitoring.
Changes in wetland water regimes can be tackled at the local level by individual land owners. At a regional level this issue is best addressed by Catchment Management Authorities via the implementation of salinity plans, wetland management plans and watering strategies. Water authorities and irrigators are also important stakeholders. The bulk water entitlement processes are a key to addressing water regime issues in floodplain wetlands. Along the coast, the Victorian Coastal Council and Regional Coastal Boards will play a leading role in co-ordinating the actions of the many stakeholders and agencies in implementing strategies to protect coastal wetlands such as estuaries and intertidal areas.
The priority management responses for land and water managers and planners are to:
- Work in conjunction with the Commonwealth and other States and Territories to implement the Ramsar Convention and to secure the best possible outcomes for wetland biodiversity through the Natural Heritage Trust and forums such as ANZECC (replaced by Natural Resource Management Ministerial Council (NRMMC)) and the Murray-Darling Basin Ministerial Council.
- Complete integrated management planning for the ten Ramsar sites in Victoria and investigate potential new sites.
- Protect important habitat of migratory waders and species listed on JAMBA and CAMBA with a focus on investigating the addition of significant sites to the East Asian–Australasian Shorebird Reserve Network.
- Ensure wetland water regimes are considered in the bulk water entitlement conversion and new allocation processes. As part of the Government’s water reform package, investigate new strategies for the effective use of environmental water on floodplains, use savings in irrigation systems for environmental purposes and improve and maintain habitat where environmental water is provided.
- Develop management agreements to encourage water authorities to take account of the environmental values of those wetlands that are part of the water distribution system.
- Implement the State Environmental Protection Policy Waters of Victoria as it relates to water quality in wetlands.
- Phase out the use of lead shot for hunting of waterfowl, in consultation with hunting organisations.
- Complete the process of identifying important and representative wetlands in Victoria and contribute to a third edition of A Directory of Important Wetlands in Australia and a national wetlands inventory.
- Promote recognition of important wetlands and encourage actions leading to their improved management.
- Promote World Wetlands Day and World Wetlands Week in Victoria as a focus for increasing community awareness of the importance of wetlands.
- In conjunction with the Commonwealth Asia-Pacific Wetlands Management Training Program, develop and implement a training program for wetland managers.
- Make information about wetlands more accessible to the community, wetland managers, students and planners through Land for Wildlife and other extension programs and by establishing a Victorian Wetlands Home Page on the internet and promoting useful publications and interpretive material.
- Improve environmental monitoring programs in wetlands with particular emphasis on Ramsar sites and encourage the community to adopt new wetland sites for monitoring through the Waterwatch Program.
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