Wetlands in a dry land: Understanding for management
Workshop held in Albury, New South Wales, 29-30 September 1997
- 1. Opening Address - Senator Ian Macdonald
- 2. The management of Australia 's wetlands
- 3. National Wetlands R&D Program: LWRRDC Scoping Review
- 4. Australian wetland policies, research and management
- 5. Wetland Research, Development and Extension: the Murray-Darling Basin context
- 6. Billabongs: management issues for floodplain wetlands
- 7. Issues in wetland management
- 8. Wetland R&D requirements in Western Australia
- 9. Issues for Western Australian wetlands
- 10. Managing wetlands on private land in the lake Eyre Basin
- 11. Wetland management in arid Australia: the Lake Eyre Basin as an example
- 12. Issues in the management of estuarine wetlands, north eastern Australia
- 13. Management of wetlands for waterbirds
- 14. Spatial and temporal variation in inundation of wetlands in the Paroo catchment of the Murray-Darling
- 15. Understanding plant germination, establishment and reproduction for wetland revegetation
- 16. Flood regimes and invertebrate communities in floodplain wetlands
- 17. The effects of drying and reflooding on nutrient release from wetland sediments
- 18. Melaleuca wetlands - wastelands or wonderlands: their benefits, threats and management
- 19. Creation of lagoons or wetlands in a tropical agricultural setting
- 20. Management issues associated with constructed wetlands in urban areas of Australia
- 21. The role of constructed wetlands for ecologically sustainable development in urban water management
- 22. The effect of livestock on wetlands
- 23. Floodplain-wetlands: Transient storage areas of sediments and pollutants
- 24. Anthropogenic threats to the viability of wetlands in northern Australia
- 25. Implications of nutrient enrichment for management of primary productivity in wetlands
- 26. Weed management in tropical wetlands of the Northern Territory, Australia
- 27. Carp: Sifting through the issues
- 28. Common carp in natural wetlands: impacts and management
- 29. Monitoring wetlands in northern Australia using RADARSAT
- 30. Can AusRivAS be adopted for monitoring and assessing Australian wetlands?
- 31. Valuing wetlands
- 32. Australian wetlands: community experiences and perceptions
- 33. Local communities and wetland management in the Australian wet-dry tropics
- 34. Issues in the transfer of R&D outcomes to wetland management
- 35. Bridging the gap: scientists, managers and community groups working together to improve a wetland
I am pleased to be able to support the publication of these proceedings from the workshop Wetlands in a Dry Land: understanding for management
The Government believes that research and development can, and must, add value to our efforts to conserve and reinstate environment values and the productive capacity of our natural resources. With this in mind ensuring a sound scientific and technological basis for the wise use of wetlands is a major objective of the Wetlands Policy of the Commonwealth Government of Australia as well as the Natural Heritage Trust, of which the National Wetlands Program is an important component.
The National Wetlands Research & Development Program was established in 1996 to support the conservation, restoration and long term sustainable management of wetlands by the Government and private sectors in Australia through targeted research and development.
Research and development on wetlands is critical to underpin the Natural Heritage Trust. While the Trust has a focus on on-ground outcomes and practical solutions to Australia 's environmental problems it also recognises the need to invest in strategic research and development. There is considerable scope for research to be an integral component of projects funded through the Natural Heritage Trust where research outputs are continually feeding into program and project design and management. This kind of research activity demands productive relationships between researchers and stakeholders; researchers need to be able to demonstrate that they can add value to other activities and communities and other stakeholders must also be able to identify their information needs and approach researchers.
The workshop, Wetlands in a Dry Land: Understanding for Management has promoted dialogue between public and private sector wetland managers and wetland researchers to translate wetland research into better on ground-management of wetlands.
I am confident that these proceedings will heighten awareness of the critical issues relating to our varied wetlands and contribute to widening the information base from which decisions and actions affecting wetlands are made.
I also hope that this document will inspire the further protection, study of, and wise use of Australia 's wetlands.
1. Opening Address - Senator Ian Macdonald
The Parliamentary Secretary to the
Minister for the Environment
Parliament House, Canberra
It gives me great pleasure to be here today at this workshop which brings together wetlands researchers and the community to tackle the question of understanding wetlands to improve their management.
One of the really important features of this workshop is the mix and diversity of participants I see around me. Among you are world class scientists in wetlands research, State policy makers, local government officers, water resource managers, landholders, industry representatives, indigenous people, representatives of community groups and probably other groups I have overlooked. This cross-section of the Australian community emphasises two things I think. Firstly, it says that wetlands conservation and management is an issue for all of us, right across the community. Secondly, it says that the answer to best practice management of our wetlands lies in effective partnerships between all the players.
We are slowly coming to realise what a priceless national asset our wetlands really are. Wetlands are the vital link between land and water. They are essential to the healthy functioning of our catchments and aquatic systems; they support an enormous biodiversity; they contribute to water quality; and they provide a multitude of benefits to society, which we are only just beginning to acknowledge. It is estimated that less than 50% of the wetlands which existed at the time of European settlement still remain. If we allow the degradation of our wetlands resources to continue, we shall see water quality continue to decline, species will disappear for ever, our economy will suffer, and our way of life will decline.
I believe, though, that the tide has turned, to use a maritime metaphor, and as a community we are slowly awakening to the need do something about our wetlands. Over the past twenty years, Australia and the world has come to appreciate the importance of wetlands. In 1971, Australia became the first nation to join the Ramsar Wetlands Convention. I 'm sure many, or most of you will know a lot about the Ramsar Convention. It was one of the earliest of the “contemporary” environment conventions, but it remains clearly relevant today because its essential theme was conservation of wetlands through wise use. The Ramsar Conference of Parties in Brisbane last year did a great deal to stimulate interest in wetlands conservation, especially in Australia, and the Ramsar Convention provides an excellent framework to start from.
That framework is picked up through the Commonwealth Government 's National Wetlands Program. The aims of the National Wetlands Program are that Australia should meet its obligations under the Ramsar Convention, and promote the conservation of Australia 's wetlands through support for activities such as management-oriented research, surveys, management planning, training programs and awareness-raising that will lead to “wise use” of wetlands by all levels of government and the general community.
The National Wetlands Program, which will work in partnership with the National Rivercare Initiative, has been enormously successful in supporting State and Territory Governments to prepare management plans to ensure that their internationally important Ramsar wetlands are appropriately managed. Through the resources of the Natural Heritage Trust, the Wetlands Program will receive additional funding of $11 million over the next 4 years and this funding will enhance the Wetlands Program 's resources for responding to current and emerging wetland management issues around the country. Importantly, for the first time, the Wetlands Program this year will support community-based projects, projects to research, survey, conserve, repair, rehabilitate, and manage wetlands, involving people right across the community.
The Commonwealth Government 's Wetlands Policy has been a major step forward. Through it, the community has a clear statement that the Commonwealth Government is committed to the care of wetlands. Among the six major priority areas identified in the Commonwealth Wetland Policy one is to ensure “a sound scientific basis for policy and management”. The Policy goes on to list strategies for achieving this, including “Developing and supporting a strategic and coordinated wetlands research effort” and “Supporting mechanisms to encourage the understanding and application of research findings”.
In 1996, the Land and Water Research and Development Corporation (LWRRDC) funded a Scoping Review to assess the potential for developing a National Wetlands Research and Development Program. The Review looked into wetland management issues and Research and Development needs across Australia, keeping in mind other major wetlands policy and management initiatives such as the Wetlands Policy of the Australian Government and the Murray-Darling Basin Commission Wetlands Management Strategy. Following the development of the Scoping Review, in September last year, Environment Australia and LWRRDC entered into a three year Agreement to deliver the National Wetlands Research and Development Program.
Senator Hill has particularly requested that I make clear just what the Wetlands Research and Development Program is and what the Commonwealth wants to achieve through it. The R&D Program represents an important component of Environment Australia 's National Wetlands Program. Environment Australia administers the R&D Program in close liaison with LWRRDC. That partnership approach ensures that both conservation and sustainable development issues are addressed - very important to the Commonwealth.
The R&D Program was established to support the conservation and sustainable management of wetlands in Australia through targeted research and development. I emphasise the word “targeted” because R&D must be focussed on key issues - issues like the role of water regimes in the biology of wetlands and the consequences of modifying those regimes. The impacts of contaminants and feral pests are other key issues, and there is also an urgent need to find ways of placing appropriate values on wetlands. Finally, there is the need to develop our capacity to monitor the health of our wetlands, to detect problems as well as successes. This focus on key issues is also very important to the Commonwealth.
The R&D Program must look to generating outcomes that are nationally applicable; once again, a priority for Commonwealth programs. And finally, the outcomes must be ones that can be applied to real, on-ground management. To be effective, those outcomes must be widely accessible and useable, particularly for community landholders. This workshop provides a chance to consider how to make that happen. The central theme for today and tomorrow is, I believe, one of finding ways of turning research resources and results into better wetlands management.
I think we are on the right track. We all have information to exchange and we must build on each others ' ideas. It 's called value-adding and we need to do it if we want to make real advances in wetland conservation. This workshop will give you an important opportunity to express your views, share, and importantly, to listen to the views, experiences and needs of other participants. I encourage you all to participate fully in the dialogue that will occur throughout this workshop. I hope that that dialogue will be a continuing one, lasting well beyond the life of this workshop.
Through the Natural Heritage Trust we are seeking to promote partnerships with the States and the community that will lead to better wetlands conservation and management and I would like to stress the importance of these partnerships.
Beyond those partnerships though, there need to be links and networks between government, researchers, private landholders, industry, conservation groups, primary producers, and the community that will foster the exchange of information and development of expertise and capacity essential if we are to achieve better environmental outcomes through the uptake and application of research results. A recent example comes to mind. In the north of Australia, we have a further exciting and even innovative initiative for wetlands involving the Commonwealth and three universities. The Environmental Research Institute of the Supervising Scientist, the Science Faculties at the Northern Territory University, James Cook University and the University of Western Australia have formed an alliance to develop cooperatively wetland and coastal environmental science, particularly for wetlands and coastal ecosystems. Importantly, it will strengthen existing efforts to link our scientific resources with those of the local communities who manage and own many of the wetlands.
In closing, I would like to return to a theme I have touched on several times already, and that is the community-wide nature of wetlands conservation and management. I do so, because in my view, that is where the best chance for our wetlands lies - with the empowerment of the community and the tapping of their enthusiasm and knowledge. The Government recognises that the Australian people, both as individuals and through their various affiliations, have a crucial role in managing wetlands.
Wetlands represent a valuable and to date diminishing resource, under pressure from such diverse interests as tourism and recreation, food and fibre production, regulation of water quality, mining, and of course the needs of the natural environment. Increasingly, governments and managers need to be aware of all stakeholders and their needs when making decisions about our wetlands. Management of wetlands and waterways must be planned for long-term sustainable wise use and this is why the National Wetlands R&D Program is so valuable.
This workshop is an important element in the process of awareness raising. Ours truly are wetlands in a dry land. Our understanding of those wetlands determines how well we will manage them for future generations.
2. The management of Australia 's wetlands
To maintain, restore and enhance the many values of Australian wetlands on a sustainable basis requires informed, soundly-based management. The general aim of the National Wetland R&D Program is to provide the knowledge on which this management is predicated. The more particular aims of the present workshop are to contribute to the development of this knowledge in two ways. Firstly, the workshop will provide stakeholders (owners of land on which wetlands occur, wetland managers, the wetland research community, and others) with an opportunity both to receive information about wetland management and the nature of the National Wetland R&D Program and contribute to and comment on the program and on wetland management issues generally. Secondly, the information given and generated at the workshop will be used in the development of a strategy for determining the future direction of the program; that is, it will be used in providing a more rigorous definition of how to achieve informed, soundly-based management.
The series of papers in the workshop program provide most of the more formal information to participants; other sources of information are informal contacts made during the course of the workshop and a series of invited written papers that, together with those presented orally, will be published as part of the proceedings of the workshop. Opportunities to contribute to the proceedings are provided by the series of open forums and by the provision of comment sheets.
Given the wide distribution of wetlands in Australia, their considerable diversity, and their many values, the development of a strategy for their more effective management is both timely and urgent. Many hazards threaten the viability of large numbers of Australian wetlands (drainage, pollution, exotic introductions, salinity, etc) and a response to these is needed now before further damage is sustained. The nature of this response, moreover, has global implications: some 80% of the land area of the world is more like Australia in general climatic terms (semi-arid, arid, subtropical, tropical) than like the temperate regions on whose wetlands most published work on wetland management is based. Clearly, the principles of management of Australia 's wetlands are of interest to wetland managers in many places elsewhere.
3. National Wetlands R&D Program: LWRRDC Scoping Review
S.E. Bunn and N. Schofield
The Land and Water Resources Research and Development Corporation (LWRRDC) conducted a Scoping Review in 1995/96 to evaluate the potential for developing a National Wetlands R&D Program. The objectives of the review were: (i) to summarise wetland resources in general terms in Australia using existing information, and identify where information required for ecologically sustainable development is lacking; (ii) to identify the key issues for wetlands management, within the context of overall natural resources management; (iii) to identify and prioritise the generic, national or regional issues for which R&D investment could bring the greatest returns in terms of maximising national benefits; (iv) to describe the current state of knowledge of the priority issues in a concise, well referenced format including the scale, impact, significance, costs, threats and opportunities; (v) to propose specific R&D requirements for each issue that will be sufficient to resolve the technical components of the problem; and (vi) to identify social, economic and policy impediments or constraints to resolving the priority issues and propose R&D or other projects that might assist in overcoming these impediments. This paper outlines the contribution of the Scoping Review to the development of the LWRRDC National Wetland R&D Program, and provides a brief description of the review process which ultimately led to the identification of priority R&D issues.
4. Australian wetland policies, research and management
Protection, maintenance and management of wetlands as a key habitat type in Australia is currently inconsistent and ineffective on the broad scale. Only two States have any direct legislative protection for wetlands, and this is limited to specific wetland types or regions. Representation within the formal conservation system is far from complete and most of the wetlands listed in the National Directory of Important Wetlands do not have formal protected status. Only two States and the Commonwealth government have wetland policies, and these are non-legislative instruments relying on cooperative compliance for their implementation.
However, there is currently an opportunity to upgrade the coverage of wetland policies across Australia. In response to the requirements of the Ramsar convention, the Commonwealth government has provided a framework for cooperative development of a national wetlands policy which will consist of the package of the policies of the States, Territories and the Commonwealth. All States and Territories without policies are required to develop a policy as part of this package.
Issues already highlighted in the Commonwealth policy include the need to develop effective incentives to encourage broadscale private conservation of wetlands, since many of Australia's key wetland types occur on private property. The lack of a sound database to evaluate the wetland resource and set priorities for future management is identified as a significant hindrance and funding has been allocated for a national inventory.
- As concern about the effectiveness of protection and management of Australian wetlands rises, areas of gaps in knowledge have been highlighted in many wetland-oriented forums. The top priorities which have been identified for management-oriented research include:
- definition of environmental water requirements for specific wetlands and river systems
- establishment of tools for rapid monitoring and evaluation of the effectiveness of management measures
- identification of environmental performance indicators
- case studies in trade-off processes to balance biodiversity conservation against economic and social demands (e.g. environmental flows)
- evaluation of the rate of loss of wetland habitat and the consequences to the community
- development of monitoring protocols and cooperative databases
- development of practical tools for assessing and demonstrating the values of wetlands to the community.For meaningful protection of wetland habitats on a broad scale across Australia, an integrated partnership package is needed that brings together policy makers, managers, communities, landholders and researchers to find a mix of solutions which target wetland conservation directly and effectively.
5. Wetland Research, Development and Extension: the Murray-Darling Basin context
This paper outlines the strategic context of wetland research, development and extension (RD&E) under the Murray-Darling Basin Commission 's Strategic Investigations and Educations funding program. It identifies the Commission 's priorities for the next three years and presents the wetlands program in the context of the Commission 's overall RD&E effort with particular reference to strategic planning initiatives currently underway.
6. Billabongs: management issues for floodplain wetlands
Billabongs exhibit the ecological features of other wetlands. They have the added characteristic of being part of the floodplain river ecosystem. As such, they have additional functions relating to their interactions with the parent river and the terrestrial riparian system. Their hydrology is determined by that of the parent river but because they are morphologically variable there is significant hydrological variability between billabongs in space and time. The ecological mosaic thus created contributes substantially to biodiversity in lowland river ecosystems. Management of rivers as human resources impinges significantly on the ecology of billabongs by effecting the temporal pattern of inundation thus (potentially) changing their seasonal hydrology, the ratio of temporary to permanent wetlands, and the biological interaction between river and billabong, thought to be important in providing resources to river biota. With increasing knowledge of billabong ecology it may be possible to restore at least some of their ecological function, without diminishing the utility of the river as a human resource, through 'benign ' changes to flow patterns in regulated floodplain rivers.
7. Issues in wetland management
A number of general issues relevant to management of natural areas is discussed. The importance of clearly stating aims and objectives is stressed, and the need for on-going assessment and adaptive management is emphasised. Matters specifically relevant to wetlands are identified. It is suggested that the most important management issues for many types of wetland are the provision and maintenance of an appropriate hydrological regime. The need to develop measures to support management by private landholders is identified as a major challenge if Australia 's obligations under the Ramsar Convention are to be met.
8. Wetland R&D requirements in Western Australia
The usefulness of wetland research to managers can be improved by better integration, at both individual and agency level, as well as through the development of R&D strategies. Matching research to the scales and measurement units used by management is important. Six research areas that provide important information for wetland management in Western Australia are listed, reference is made to some current research in these areas, and additional research topics are suggested.
9. Issues for Western Australian wetlands
Wetlands in Western Australia are diverse and unique. Once abundant in many areas, their numbers have been greatly reduced by drainage for agricultural purposes. In addition, many remaining wetlands have been severely degraded. The paper discusses several issues: Environmental Protection Authority initiatives; other initiatives from both the private and public sector of the community; statutory Environmental Protection Policies (Environmental Protection Authority); recent governmental initiatives of relevance to wetlands; Western Australian Ramsar sites; northern and south-western rivers; the Swan-Canning estuarine system; and other issues which threaten the conservation and management of wetlands (e.g. canal development, fire-fighting capabilities).
10. Managing wetlands on private land in the lake Eyre Basin
The arid river-floodplain systems of the Lake Eyre Basin are geomorphologically, hydrologically, and ecologically complex, and might be described as series of extensive and widely dispersed, predominantly ephemeral wetlands, rather than as rivers in the conventional sense. These systems comprise geographically vast assemblies of channels, waterholes, swamps, claypans and shallow lakes. They exhibit a pulsed ecology driven by irregular, variable and unpredictable flood events. Large waterholes comprising the major permanent aquatic features of these systems provide refuges for biodiversity within a very arid landscape. The major proportions of these wetlands lie within “private” pastoral lease ownership.
Very significant natural heritage values, recognised at both national and international levels, exist in the Lake Eyre Basin wetlands. Historically, the major industry impacting directly on these wetlands has been pastoralism, but in recent times additional impacts have resulted from petroleum exploration and production and tourism. Adverse impacts of these industries on arid zone landscapes and biodiversity have been documented. Management of these industries will increasingly need to focus on the protection of biodiversity and ecological integrity to safeguard the superlative natural values of these wetlands. Recent proposals to introduce irrigated agriculture to Cooper 's Creek have revealed the potential vulnerability of arid zone rivers and wetland systems to degradation from inappropriate development in the absence of ecologically sound catchment management policies.
Future management will be assisted by fundamental research on the relationship of hydrological events (both flooding and drought) to ecological pattern and process in these wetland systems. Guidelines for ecologically sustainable pastoralism in the arid zone and its wetlands need further development.
11. Wetland management in arid Australia: the Lake Eyre Basin as an example
Arid zone wetlands differ markedly from those in humid zones, particularly in the unpredictable variability of their climatic and hydrological regimes, and in the physical, chemical and biological characteristics which depend on these regimes. The wetlands of arid Australia, and particularly those of the Lake Eyre Basin, demonstrate these characteristics in an extreme form. Scientific understanding of the nature of these wetlands and general recognition of their value are both just beginning.
The Lake Eyre Basin wetlands have been subject to the impacts of stock grazing since the mid-nineteenth century, but development pressures have increased recently with new proposals for irrigation and mining. These proposals have highlighted the vulnerability of the unregulated and unpolluted state of these wetland systems, and the inadequacies in the information, resources, public awareness, policies, procedures and management structures for a river basin covering one seventh of the continent.
Despite a recent in-principle agreement between the State and Federal Governments for catchment management in the Lake Eyre Basin, there is a present and foreseeable poverty of government resourcing of research and management in the region. This places the onus for innovative assessment, management and even research initiatives onto community groups with interests in these wetlands. Two recent workshops on the implications of irrigation proposals for the Cooper and Paroo wetlands have demonstrated the value of collaboration between local and non-local interest groups in empowering local communities, informing debate, establishing and enhancing shared values, enlisting national public support, and applying pressure for political change. A substantial outcome of this process to date has been a Queensland Government veto on the Currareva irrigation project for Cooper Creek. Prospects include the development of alliances between scientists, local communities and conservation groups, leading to collaborative research and management.
12. Issues in the management of estuarine wetlands, north eastern Australia
G.P. Lukacs and C.M. Ludescher
An introduction to estuaries in north-eastern Australia is presented which discusses their types, and briefly, their role in hydrological and biological processes. Issues which affect the sustainability of the resource, together with a discussion of both direct and catchment based impacts, are presented. Research priorities for the region are also suggested.
13. Management of wetlands for waterbirds
Nearly 20% of Australia 's bird species depend on wetlands. Waterbirds are highly mobile fauna sometimes relying on different wetlands for breeding and feeding. A suite of waterbird species (mainly Charadriiformes) migrate from the Northern Hemisphere each year after breeding so Australia also has some international responsibilities for these fauna. The most significant challenge for waterbird management in Australia is loss of habitat. Wetland loss on the continent has contributed to declines in the populations of many waterbird species. Possibly the most significant cause is diversion of water from rivers which supply wetlands. Downstream wetlands receive less water which means they flood less area and do not hold water for as long as they used to. The Macquarie Marshes is now at least 40-50% smaller than it used to be. Areas of wetland vegetation are reduced. Numbers of waterbirds, diversity and the sizes of breeding colonies have all declined. Similar trends are apparent on other wetlands such as the Gwydir wetlands. There are also other significant threats to habitat: weed invasion (e.g. Mimosa pigra), grazing, and pollution. Traditional forms of conservation such as reserves, listing of wetlands under international agreements do not effectively deal with many of these threats to wetlands. Critical research and management issues should concentrate on determining impacts of diversion of water from wetlands on the viability of wetland habitat in relation to threatening processes. The catchment is often the most critical scale for management and research.
14. Spatial and temporal variation in inundation of wetlands in the Paroo catchment of the Murray-Darling
Wetlands are diverse and abundant, though generally intermittent or episodic in the Paroo catchment of the Murray-Darling. The salient limnological features and the temporal variation of six major types of wetlands (saline lakes, small freshwater lakes, large terminal freshwater lakes, riverine waterholes, pans of various types and lignum swamps) are presented. Many are threatened by reduction in flows of the Paroo river due to water abstraction for irrigation, while some are sedimented, and others suffer damage by exotic fish, feral pigs and human recreation. Numerous and sometimes dubious management and conservation reports on the area almost outnumber papers on its basic science. It is time there was more attention to field research and less to bureaucracy. Management reports might then be written intelligently.
15. Understanding plant germination, establishment and reproduction for wetland revegetation
This contribution discusses how plants, both as individuals and in communities, function as components and in processes in wetland systems. It reviews what we know and what we need to know about how the various stages of plant life cycles respond to natural and human induced changes in environmental conditions, in particular water regime. If we understand how the essential stages of a plant's life cycle, germination, establishment and reproduction, respond to environmental change we will be in a better position to predict the consequences of changes and to use these predictions for managing wetlands. If the needs for understanding of plant responses are defined in both scientific and management terms, scientists can focus on designing and delivering the best scientific information for use in managing wetlands.
16. Flood regimes and invertebrate communities in floodplain wetlands
A.J. Boulton and K.M. Jenkins
The assemblage composition of aquatic invertebrate communities in all floodplain wetlands is influenced by the regime of flooding, including the duration, timing, frequency, and intensity of flooding and the source of water (including connectivity with the main river channel). To invertebrates with seasonal life cycles (e.g., aerial insects), timing of flooding is important. If the duration of flooding is too short, aquatic stages may not be completed, reducing recruitment. When the frequency of flooding is reduced, emergence from resting stages of invertebrates in floodplain sediments declines, leading to lower biodiversity. Conversely, an increase in flooding frequency or duration may permanently inundate wetlands that usually dry, favouring establishment and spread of exotic predators (e.g., carp) and leading to local extinction of invertebrates that occur only in temporary waters. Floodwater from different sources varies in water quality (i.e., nutrients, dissolved carbon, turbidity) and biota (e.g., zooplankton, aquatic invertebrates, plants). Depending on the source, the composition of a wetland may vary because of the different colonists or the different ambient conditions that favour particular taxa. Spatial patterns of flooding and connectivity to the main river or its anabranches largely determine the composition and establishment of the colonists. These spatial patterns are determined by floodplain topography, patterns of rainfall and wind in the catchment, and the flood regime.
Our knowledge of the mechanisms by which the flood regime influences the invertebrate assemblage composition of floodplain wetlands is poor and fragmented, and only recently have models been proposed to explain how floodplain wetlands might function. These models were developed for wetlands in more temperate parts of the River Murray floodplain and may not be totally appropriate for wetlands in more arid areas (e.g., Paroo River or Cooper Creek floodplains) or the wet-dry tropics. We urge coordinated research into the way flood regime influences the quantity and quality of water entering floodplain wetlands and how these influence invertebrate habitat diversity and assemblage composition as well as other wetland ecosystem components. Variability is the key. We suggest that the history of flooding at several temporal scales (years to decades) is also important despite the fact that most invertebrate life cycles seldom exceed one year. This is because resting stages may persist for much longer periods and because habitats created by aquatic plants and woody debris are essential for maintaining invertebrate biodiversity. We have too few long-term data on floodplain wetlands in different parts of Australia and we are missing key information on lag effects and longer-term repercussions of extreme floods and droughts.
17. The effects of drying and reflooding on nutrient release from wetland sediments
A. McComb and Song Qiu
This paper discusses the implications of drying and flooding effects on nutrient release from sediments in wetlands. It discusses the role of sediment properties, phosphorus and nitrogen transformations, carbon cycling, drawdown and macrophyte control, and modelling. Finally, comments on management issues are made. In summary: Drying and refilling cause substantial changes in water quality. The effect depends on (a) sediment properties (sediment composition; nutrient and organic content); (b) type of drawdown (gravity or evaporative); (c) severity of drying (proportion of drying area, rate of drawdown, degree of dewatering, temperature and time of sediment drying and weathering); (d) conditions of refilling (origin of water, degree of sediment disturbance). Sediment properties are the key to physical, chemical and biological changes during drying and reflooding, as they affect nutrient transformations and exchange between sediment and water. Changes may include particle aggregation and sediment consolidation, phosphorus adsorption and desorption; organic degradation, nitrogen transformation, and stimulation of microbial processes. Phosphorus transformations in sediments during drawdown depend on many factors. There is a higher probability of stimulating phosphorus release than of reducing phosphorus concentration during the reflooding of dried sediments, particularly in organic-rich wetlands. Stimulation of phosphorus release and algal production is most likely to result from an evaporative drawdown event. Concentrations of inorganic nitrogen (ammonia and nitrate) often increase during or after drawdown, although the effect may be short-term. Such release has the potential to stimulate N-limited algal blooms. Drawdown has been used effectively in controlling macrophytes. The levels of sediment dewatering, freezing or hot climate conditions generally determine the levels of macrophyte reduction. However, control of macrophytes is often species specific. The elimination of macrophytes may increase the probability of algal blooms.
18. Melaleuca wetlands - wastelands or wonderlands: their benefits, threats and management
Melaleuca wetlands or “tea tree swamps” are regarded by many as unattractive, unproductive, boggy, mosquito breeding wastelands. This misconception has consequently resulted in extensive clearing, drainage and filling of Melaleuca wetlands. In South-eastern Queensland alone, it has been estimated that 90% of Melaleuca forests have been lost to agriculture and urban development. Melaleuca wetlands however provide protective buffer zones between our shorelines, estuaries and river systems, protecting these waterways from siltation and nutrient runoff. Removal of these buffers causes increased runoff, increased sediment load and nutrient concentrations, acid sulphate soils, deterioration of aquatic ecosystems and loss of wildlife habitats and biodiversity. Melaleuca wetlands are in fact one of natures wonderlands and are vital for ecological sustainability. To preserve our remaining Melaleuca wetlands, State and local governments and private landholders need to recognise the values and benefits of these wetlands and adopt greater responsibilities for sustainable management. Community involvement in projects is vital to increase public awareness of the significance of Melaleuca wetlands.
19. Creation of lagoons or wetlands in a tropical agricultural setting
Details are given of the construction of a lagoon in northern Queensland. The costs and benefits are outlined. The benefits greatly outweighed the costs.
20. Management issues associated with constructed wetlands in urban areas of Australia
W.D. Williams, I. Pettman, P. Manning and I. Falconer
In many urban areas of Australia, artificially constructed wetlands are a significant feature of the environment. They have been constructed for several reasons: to mitigate flooding, to improve water quality, to decrease sediment loads in urban runoff, to offer visual relief in the urban landscape, and to give opportunities for various forms of both passive and active recreation. However, notwithstanding the greater recognition now accorded wetlands values, rather little attention has been given to the several difficulties associated with their development, construction and management. In their development, for example, significant sociological, political and economic difficulties often intrude. Their construction often involves the resolution of several locally important problems such as where to dispose of excavated material, what form should the wetland take, and can dust and noise of construction be minimised. Their management usually involves many ongoing issues of a biological sort.
The most important biological issues involved include plant nutrient management (to avoid excessive algal and macrophyte growth), the potential presence of blue-green algal toxins, nuisance insect control (especially of those species which serve as vectors of arboviral and other human diseases), and restricting the growth of noxious plant and animal species (often including exotic species). The nature and severity of these issues varies geographically but in all cases there remains a need for ongoing wetland management that includes prophylactic, monitoring and remedial activities to ensure that perceived wetland values continue to be maintained. Unfortunately, activities of this sort are often assigned a lower priority than is required for effective management; it is easier to obtain short-term capital funding for projects of clear community benefit and visible political advantage than it is to obtain long-term recurrent costs for proper maintenance of a wetland.
21. The role of constructed wetlands for ecologically sustainable development in urban water management
Most urban infrastructure concerned with the disposal of wastewater is not designed in an ecologically sustainable way. It is possible, however, to restructure existing infrastructure or develop new strategies of water management which do support the notion of ecologically sustainable development. This concept is considered with particular reference to Adelaide. The Government of South Australia, through its former MFP Development Corporation (MFPDC) has taken a leading role in this matter. The paper discusses MFPDC initiatives, MFPDC wetlands, a wetlands monitoring and research program, and better models for urban water resource management.
22. The effect of livestock on wetlands
Grazing by domestic livestock has a major impact on wetlands in Australia. This paper describes what these effects are, sources of variance in these effects, relationships with other factors, and the management of livestock in and around wetlands.
23. Floodplain-wetlands: Transient storage areas of sediments and pollutants
Two examples of sediment and pollutant storage in floodplain–wetland systems are presented. These examples highlight that: 1), the distribution of sediment and pollutants within these systems is highly variable and distinct morphological units (ie. wetlands) appear to be a foci for pollutant accumulation; 2), high rates of sediment and pollutant accumulation do occur in association with catchment disturbance; and 3), floodplain–wetlands are both a sink and source of sediment and pollutants. Effective management of these systems requires an integrated approach in which all land and water issues are considered.
24. Anthropogenic threats to the viability of wetlands in northern Australia
The significance of pastoral and mining to northern Australia 's wetlands is introduced with emphasis on mining activities. In particular, open pit mining often leaves water-filled voids which in some areas may seasonally overflow and drain into coastal wetlands. Many of these voids, for example the defunct copper/uranium mine at Rum Jungle, contain water with low pH and high dissolved metals concentrations due to the process known as 'acid mine drainage '. In the Rum Jungle voids, mid-year seasonal mixing affects the water quality of overflow which exits the voids some months later in the wet season. As with other mining voids in the region, soluble (and particulate) metals in the overflow may gravitate into coastal floodplains and wetlands. Long-term deposition of metals in these environments will inevitably affect their viability. Detailed modelling of these voids to asses the likelihood of acid (and soluble heavy metals) generation is now possible. This, in conjunction with astute engineering design, can reduce the likelihood of damage to tropical wetland ecosystems. Recent research into the modelling of open-pit voids is described.
25. Implications of nutrient enrichment for management of primary productivity in wetlands
P.I. Boon and P.C.E. Bailey
Australian wetlands are commonly subjected to nutrient enrichment. The effects of cultural eutrophication on the wetland biota are not known in sufficient detail for land and water managers to be able to predict accurately the ecological consequences of nutrient enrichment. Indeed, even fundamental information on wetland vegetation dynamics, such as whether nutrients are the factor limiting biomass accumulation, are lacking. Moreover, if nutrient limitation exists, it is not known whether nitrogen or phosphorus is the element of concern. Overseas studies have shown a general tendency for macrophytes to be lost from wetlands that have been subjected to nutrient enrichment, and have demonstrated a sequential replacement of emergent and submerged macrophytes by attached macroalgae and, eventually, phytoplankton. It is not clear whether the patterns of vegetation shift reported for temperate northern- hemisphere wetlands occur in Australian wetlands.
26. Weed management in tropical wetlands of the Northern Territory, Australia
M. Douglas, M. Finlayson and M.J. Storrs
This article addresses the issue of weed management in wetlands of tropical northern Australia. Several descriptions of the major weed species are given (Acacia nilotica, Brachiaria mutica, Echinochloa polystachya, Hymenachne amplexicaulis, Eichhornia crassipes, Mimosa pigra, Parkinsonia aculeata, Pistia stratiotes, Prosopsis limensis, Salvinia molesta and Tamarix aphylla). Ecological impacts are discussed together with the causes of weed problems, weed control and land-use. Recommendations for future R&D are given.
27. Carp: Sifting through the issues
Carp are an introduced fish, distributed through the Murray-Darling Basin, with the potential to colonise other catchments. Carp are a threat to wetland values, but they are only one of many threatening factors. There is a need to distinguish between the most conspicuous and recent factor and other pre-disposing or well-established factors, as this increases management options. A similar re-evaluation needs to be applied to introduced species which are socially acceptable, unlike carp.
28. Common carp in natural wetlands: impacts and management
F. Rechnagel, F. March, S. Matthews and N. Schiller
A comparative limnological study is described of two Lower Murray Wetlands with different abundances of carp. The wetlands studied were Pilby Creek and Lock 6. The latter wetland had abundant carp, the former fewer. Management of carp abundance led to wetland recovery.
29. Monitoring wetlands in northern Australia using RADARSAT
This research is based on radar 's unique ability to detect and image water under trees. RADARSAT data will be used sequentially over a period of three years to map the pattern and changing distribution of flooding in the wetlands of the Alligator Rivers region of Kakadu National Park occasioned by seasonal climatic conditions and human impact. While many wetlands in Northern Australia have been relatively undisturbed by human activities in the past, increasingly they are coming under threat from saltwater intrusions, invasion by exotic weeds, degradation by feral animals, increased pollution from agriculture and recreational use. This baseline study will provide the environmental knowledge and methodologies for assessing and monitoring other wetlands in Australia.
30. Can AusRivAS be adopted for monitoring and assessing Australian wetlands?
Current research in south-western Australia indicates that a predictive modelling technique used for the assessment of the biological quality of rivers in Australia (AusRivAS) and the United Kingdom (RIVPACS) may also be usefully applied to the monitoring and assessment of wetland ecosystems. The River InVertebrate Prediction and Classification System (RIVPACS) was developed by the Institute of Freshwater Ecology to generate predictions of the macroinvertebrate fauna to be expected at a river site in the absence of disturbance by human impacts. Each prediction is based on a small number of environmental variables used to characterise the site. The fauna predicted can then be compared with the actual fauna present at the site. Differences between observed and expected values provide a measure of the biological quality of the site. A similar approach, AusRivAS, based on 1,500 Australian stream and river sites, has been implemented as part of the National River Health Program.
This approach has value not only as a technique for assessing wetland quality as part of environmental monitoring programs but also provides a means of assessing the effectiveness of wetland creation and restoration projects. Results from research in progress suggest that the AusRivAS methodology is applicable to wetlands, but the question remains as to whether the needs and the resources exist to adopt this approach on an Australia-wide basis.
31. Valuing wetlands
Wetlands are valuable to the community as protected areas. They harbour endangered species, they act as water filters, they are used for recreation, etc. However, the resources which constitute wetlands can also be valuable to society in other, developmental uses. When drained, the land may be valuable for agricultural or residential purposes. The water can be diverted to support the production of irrigated crops. Whilst there are strong incentives through markets for the developmental values of wetland resources to be secured for society, many of the conservation values of wetlands are not marketed and hence do not offer a profit motive for their provision. This skewed incentive structure creates pressure for too few wetlands to be retained in a protected state unless corrective measures are put in place. These could include public sector intervention in the form of direct ownership of protected wetlands, the regulation of wetland resource use, the installation of incentives for private owners to protect wetlands or adjustments to private property institution to balance the incentive structure between protective and exploitative uses of wetlands. However, before such measures can be set up, it is important that their development be informed regarding the extent to which the community values the alternative uses of the wetland resources. It is through the estimation of values that the balance of resource usage which provides maximum community well-being can be assessed. However, estimating the values of non-marketed benefits in dollar terms so that comparison between alternatives is facilitated provides some particular challenges to economics.
32. Australian wetlands: community experiences and perceptions
Dirty, stinking, useless, mosquito-ridden wastelands or places of great beauty, diversity, productivity and spirituality that are essential components of the riverine environment and the Australian landscape? Community perceptions of just what wetlands are and their value in the natural environment depend largely on individual experience, knowledge and ability to 'read ' the land. Like our wetlands, community perceptions and values are dynamic and changing as we learn more about how these complex ecosystems function and interact with the rest of the environment.
The fate of our wetlands has and will continue to be determined by the human values placed on them and the environment of which they are but one element. The majority of Australian wetlands is in private ownership and used and destroyed for a multitude of purposes. Increasingly, communities are questioning the management and use of floodplain wetlands in arid Australia in particular. Greed and ignorance of the impacts of development have been features of modern agriculture that have galvanised the broader community to demand that we develop a new value system to protect our natural environment.
Fortunately, understanding of the benefits of healthy wetlands is increasing and some of this new understanding is being used by communities and individuals to determine appropriate management arrangements that can satisfy a range of social, economic and environmental objectives.
Debate and conflict over water resource management and therefore wetland management/use will not diminish with time. Resolution of conflict is complex, difficult and reliant on the availability of good biophysical data and an integrated and credible research effort that involves the stakeholders and management agencies. We need less environmental and irrigation industry fundamentalism and hysteria, and more focus on the provision of high quality science and innovation and enabling reasoned debate to achieve acceptable outcomes.
Conflicts that arise over wetland management can only be resolved by the provision of data and credible science in a way that the community can test against their own experience in their own time. This is essential if we are to sustain the use and conservation value of these special wet lands in our dry land.
33. Local communities and wetland management in the Australian wet-dry tropics
M. Finlayson, L. Thurtell, M. Storrs, R. Applegate, P. Barrow and P. Welling
This article addresses the issue of weed management in wetlands of tropical northern Australia. Several descriptions of the major weed species are given (Acacia nilotica, Brachiaria mutica, Echinochloa polystachya, Hymenachne amplexicaulis, Eichhornia crassipes, Mimosa pigra, Parkinsonia aculeata, Pistia stratiotes, Prosopsis limensis, Salvinia molesta and Tamarix aphylla). Ecological impacts are discussed together with the causes of weed problems, weed control and land-use. Recommendations for future R&D are given.
34. Issues in the transfer of R&D outcomes to wetland management
This paper discusses a number of issues involved in the transfer of knowledge concerning R&D in wetland management to those who need such information. Among issues discussed are the knowledge base, pressures on scientists to communicate, models of communication, and implications for distributing knowledge.
35. Bridging the gap: scientists, managers and community groups working together to improve a wetland
R. Lyall and W. Wright
Lake Guthridge is a small artificial wetland near Sale, Victoria. A number of management problems has arisen. This paper discusses these problems and how they are perceived by the community. Possible resolutions are discussed. The main thread of the paper involves a description of how the local community has kept informed and provides a model for possible resolutions of management problems.