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Water for the environment: wetlands |
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The Location and Extent of Wetlands in NSW Threats to the Wetlands of NSW
Wetlands of International and National Importance Summary of Wetland Fact Sheets References and Further Reading
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Why are Wetlands so important?
Wetlands are ecologically, economically and socially important (NSW Government, 1996). They are often cited as among the most productive ecosystems on Earth, existing as multiple value systems. The functions and services provided by wetlands are many and varied. So whether you’re an irrigator, a farmer, a city slicker, a greenie, a member of a community group, or government employee and you live in a catchment, which we all do, then wetlands are important to you! Please read on to discover some of the reasons why wetlands are so important. [ TOP ]
Wetlands are the habitat for a diverse range of animals including waterbirds, frogs, invertebrates and fish species, as well as water-loving plants such as sedges, rushes and various tree species like river red gum. Some wetlands in NSW like the Macquarie Marshes, Yantabulla Swamp (on the Upper Paroo River), the Paroo River Overflow Lakes and the Bulloo Overflow, regularly support more than 50,000 birds, (DLWC, 1996). Please click here for more information on the amazing array of Plants and Animals commonly found in NSW Wetlands. [ TOP ]
Wetlands are the border between terrestrial and aquatic environments. They become strategic refuge areas in times of drought, often supporting plants and animals that are found nowhere else. It is estimated that around 550 native plant species, 52 fish species and 194 bird, amphibian and reptile species are found in NSW wetlands. Several of these plants and animals are listed as threatened or endangered under the NSW Threatened Species Conservation Act, 1995. Migratory bird species listed under international conservation agreements with Australia (JAMBA and CAMBA) are found in wetlands (DLWC, 1996). Please click here for more information on the amazing array of Plants and Animals commonly found in NSW Wetlands. [ TOP ]
Click here to down-load an A4 sized Fact Sheet on Wetland Fauna in NSW [ TOP ]
Wetlands provide important breeding and nursery areas for a large range of animals including birds, fish and invertebrates. Estuarine wetlands, which support vegetation such as mangroves and salt marsh, have a well recognised link with the productivity of estuarine and offshore fisheries. It is estimated that two-thirds of the fish caught off the NSW coast spend some part of their life cycle in wetlands and estuaries. Many seasonally flooded inland wetlands are also highly significant for waterbird breeding (DLWC, 1996). [ TOP ]
Wetlands often form significant buffer zones and visual screens between different landscapes and waterways. Buffer zones can be used to reduce a number of effects including runoff from surrounding land, the amount of sediments, nutrients and contaminants entering wetlands, the effects of browsing animals, the degree of invasion by pest plant species and the impacts of drainage. Buffer zones also act as habitat corridors for native fauna. The shape of the buffer zone should as far as possible coincide with the shape of the wetland (Buxton, 1991). The width and length of buffer zones depends on location, slope, soil type, substrate, vegetation and their purpose. [ TOP ]
Wetlands improve water quality downstream. As water passes through the wetland it slows down, allowing sediment to settle. Many nutrients and other pollutants in the water or attached to the sediment, are removed as the water passes through the wetland. It has been estimated that the natural wetland on the Crackenback River near Thredbo removes up to 44 per cent of incoming phosphorus and 66 per cent of nitrogen. By removing nutrients, wetlands decrease the likelihood of algal blooms forming further downstream. The quality of both surface and groundwater may be improved as it flows through wetlands (DLWC, 1996). [ TOP ]
Many wetlands are highly productive ecosystems because of their ability to recycle nutrients. Fungi and bacteria break down dead plants and animals for other plants and animals to use. The nutrients are captured by the wetland plants from the water column and sediments, and are recycled through the wetland and associated aquatic ecosystems. During this process a gas called hydrogen sulphide (otherwise known as rotten egg gas) and methane are produced. See "Wetland Plants and Animals" for more information on Microbes. Many wetlands in NSW are adapted to dry out periodically. This is critical for nutrient cycling because during the drying period the accumulated matter is exposed to the air starting the decomposition process. When water returns to the wetland, a sudden burst of nutrients becomes available for plants, and, animals. The result is a highly diverse and productive system bringing about seasonal changes in plant mix and animal feeding patterns, including waterbirds, fish, native mammals and cattle. See "Wetland Plants and Animals" for more (DLWC, 1996). [ TOP ]
Wetlands detain floodwaters or runoff, reducing downstream flood peaks which could otherwise cause erosion and flood damage in the catchment. For example, the Millewa/ Barmah red gum forests on the Murray River reduce flood peaks by 40 to 50 per cent during moderate to major floods (DLWC, 1996). [ TOP ]
Wetlands are storehouses of knowledge about past ecological communities and climatic sequences. Analysis of sediments, such as looking at pollen records, make wetlands valuable places for scientific research. Much of the scientific work, however, is looking at present conditions in order to gain a better understanding of how wetlands function. Studies are conducted on the ecology and behaviour of waterbirds, fish, frogs and insects, as well as plant ecology (DLWC, 1996).
Wetlands provide excellent sites for the study of biology and ecology. For example, each year, about 10,000 school students and a further 20,000 members of the general public visit the Wetlands Centre, Australia (formerly the Shortland Wetlands Centre) at Hexham Swamp near Newcastle (DLWC, 1996). [ TOP ]
Wetlands can be sites of groundwater recharge. This is particularly the case in an elevated landscape where the wetland is able to retain surface waters. Unlike a creek which tends to dry out quickly, a wetland drains slowly and hence retains waters that would otherwise flow away. For example, a chain of wetlands found in Centennial Park, Sydney that discharge to Botany, are groundwater fed in the upper reaches and act as a filter for highly polluted surface waters (DLWC, 1996). Please click here for more information on Wetlands and Groundwater. [ TOP ]
Many wetlands are important sites for bird watching, canoeing, duck hunting, fishing and other recreational pursuits (DLWC, 1996). [ TOP ]
Wetland vegetation growing along the foreshores of lakes, estuaries and river banks helps to protect them from erosion. Common species include Cumbungi, Common Spike Rush and Common Reed (DLWC, 1996). [ TOP ]
Wetlands are an important feature in the landscape, becoming a focal point for the community, particularly in inland NSW where they might be the only water body in the local region. This is the case with many tableland wetlands such as Polblue Swamp within the Barrington Tops National Park. Wetlands may be particularly significant to Aboriginal people as a traditional and important source of food and water, as well as being a site of cultural ceremony. For example, the recent discovery of an Aboriginal burial ground within Lake Victoria shows that the area was a centre of vast activity and holds deep cultural significance (DLWC, 1996). [ TOP ]
The Aboriginal Heritage of New South Wales encompasses a wide range of elements, all of which are important to contemporary Aboriginal people as a manifestation of their long cultural history and association with the land. Aboriginal heritage forms an integral part of a living and dynamic culture. It is also significant to Australia's non-indigenous society, as it represents a part of the cultural history of this continent.1 The principal State legislation dealing with the management of Aboriginal heritage is the National Parks and Wildlife Act 1974. This Act provides for the protection, preservation and management of all Aboriginal relics throughout NSW, irrespective of land tenure, and administered by NPWS. Aboriginal heritage issues that are specifically dealt with by the legislation include artefacts (relics), sites and places of ceremonial significance. Further information on Aboriginal heritage and other heritage can be found on the Heritage pages of the NSW National Parks and Wildlife website. 1 Young, R, Hawkesbury Nepean Catchment Trust, Hartman, R., Radcliffe, M., Grose, J. and English, T. (1999). "Legislative Framework". Chapter 5 in The Constructed Wetlands Manual. Volume 1. Department of Land and Water Conservation, Sydney.[ TOP ]
Wetlands provide valuable grazing for cattle and sheep. During droughts, wetlands provide feed when other areas are depleted. The challenge is to use the grazing benefit without permanently degrading its ecological values. It is estimated that the wetlands in the Lower Gwydir Valley can carry double the number of stock per hectare than the surrounding dryland pastures. Prolonged intensive grazing on some properties may have adversely affected the ecology of these wetlands. Unfortunately the impact of domestic livestock on the ecological processes in wetlands is poorly understood (DLWC, 1996).
With proper management, forestry can be carried out without significantly degrading the other values of wetlands. The river red gum forests of the Murray River floodplain provide valuable timber resources, worth about $26 million annually to the regional economy (DLWC, 1996). [ TOP ]
In some of the more ephemeral (or transitory) wetlands, it may be possible to undertake limited cropping, providing that it does not interfere with the natural flooding and drying cycle, or contaminate the surface or groundwater through the use of pesticides, herbicides or fertilisers (DLWC, 1996).
Wetlands may be significant areas for mineral deposits such as gold, as well as important sites for sand and peat mining (DLWC, 1996). [ TOP ]
Some wetlands may be regarded as more valuable than others due to their location, size, species composition and other attributes that are locally or regionally significant (DLWC, 1996). Please click here for more information on Wetlands of International and National Importance in New South Wales.
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