Theme 5: Foodwebs and biodiversity

Theme Leader: 
Stuart Bunn

Stuart Bunn

Foodwebs describe ‘who eats who’ in ecosystems.  Many human activities affect aquatic food web structure and hence important ecosystem processes.  In tropical aquatic systems, the sources of organic matter that drive the foodwebs are largely unknown.  In Theme 5 we are:

  • identifying sources of organic matter
  • developing models that predict the effects of land use change on foodwebs and aquatic biodiversity
  • developing tools for determining environmental flows and monitoring biodiversity and ecological condition

Projects

5.1: Bottom up and top down control of tropical river food webs
Michael Douglas

The food webs of Australia's tropical rivers are poorly understood yet provide the foundation for healthy rivers.  This project will explore how these food webs are structured to support complex river ecosystems.  Using a variety of experiments scientists will identify the sources of organic matter which kick-start tropical river food webs, which animals exert a strong control in the food chain and how land and water based food webs relate to one another.

5.2: Refugial Pools. Importance of waterholes as aquatic refugia and the biophysical processes that sustain them
Stuart Bunn

River waterholes are a critical refuge for aquatic plants and animals when rivers stop flowing and are also highly valued by local communities.  Unfortunately waterholes are also vulnerable to increasing water demands, uncontrolled stock access, fishing pressure and the effects of climate change.  This study seeks to understand how waterholes in northern Australia respond to such pressures.

5.3: River-floodplain food web subsidies
Stuart Bunn

As the wet season flows overtop river banks, fish and other animals make the most of expanded feeding grounds, moving out onto the floodplains.  As the floodwaters recede, these animals take the nutrients and energy obtained from the floodplain, back to the river channel.  This project will describe floodplain food webs, quantify the contribution of subsidies to, and from the floodplain, and determine how some current land management practices are affecting the floodplain food webs of northern rivers.

5.4: Assessing the effect of urbanisation and catchment development on ecosystem health in estuaries
Michele Burford

This project will assess the effects of different land-based development pressures on the assets and values of northern estuarine ecosystems.  Research will first focus on the effects of urban development in Darwin Harbour.  The second part of the project will focus on the effects of agriculture and potential water resource development in the southern estuaries of the Gulf of Carpentaria.  In particular, young prawns living in the estuary will be studied.

5.5: Flow-ecology relationships for biodiversity and ecosystem processes
Peter Davies

Water managed and 'allocated' to the environment is commonly known as 'environmental flows'.  The critical step in determining appropriate environmental flows is predicting how particular changes in river flows might affect natural ecological assets.  This project will investigate the relationships between flow and several specific assets of tropical rivers.

5.6: Flow impacts on estuarine finfish of the Gulf of Carpentaria
Ian Halliday

Our current knowledge suggests that flows of freshwater into estuaries play a significant role in determining the numbers of fish that live there.  This project aims to increase our detailed understanding of how freshwater flows affect some key estuarine species.  This is crucial if we are to manage water resources in a manner that minimizes negative impacts on estuaries.

5.7: Environmental flow tools for northern rivers (synthesis project)
Peter Davies

There is growing interest in developing and allocating the water resources of tropical Australia.  The big question is how much water  can we extract for water development and how much do we need to retain to sustainably manage the ecological health of aquatic systems?  This project will derive a set of 'rules' for people managing tropical rivers that help them decide on how to allocate water to the environment.

5.8: Biodiversity and HCVAE. Bioregionalisation conservation priorities and predictive models of aquatic biodiversity
Jane Hughes

Biodiversity is a feature of aquatic ecosystems that is often valued by different members of the community.  To effectively manage aquatic biodiversity, we need to know where the areas of high biodiversity are.  It is also useful to know what causes some areas to have high biodiversity and others not.  This project aims to answer these questions and so define biologically unique regions (bioregions) within northern Australia, based on patterns of aquatic biodiversity.

Publications

Type: Presentation
Titlesort icon Type
08/2008 Age and Growth Patterns of the bull (Carcharhinus leucas) and pigeye (C. amboinensis) sharks in NT waters, Coast 2 Coast Conference, Darwin 2008 Presentation
08/2008 Conceptualising the natural flux regime in wet dry tropical rivers, Coast 2 Coast Conference, Darwin 2008 Presentation
June 2009 Daly River fish and flows: summary of key findings Presentation
09/2009 Ecological watering requirements in northern Australia Presentation
12/2008 Environmental flows for northern Australian river and estuaries, Coast 2 Coast Conference, 2008 Presentation
October 2008 Environmental flows for northern Australian rivers and estuaries Presentation
2008 Linking catchments to the coast – can the development of northern Australia negatively impact on the health and productivity of estuaries? Coast 2 Coast Conference, 2008 Presentation
08/2008 Seasonal contrasts in carbon budgets and ecological processes on a tropical floodplain river in Northern Australia, Coast 2 Coast Conference, 2008 Presentation
July 2009 Seasonal contrasts in carbon budgets on a tropical river floodplain Presentation
July 2009 Spatial variation in aquatic food web structure across tropical riverine landscapes Presentation
09/2009 The significance of water flows for estuaries Presentation
Type: Report
Titlesort icon Type
09/2009 Biogeochemical processes and sewage markers in Buffalo Creek, Darwin Report
Type: Newsletter
Titlesort icon Type
05/2007 Daly River fish and flows project: an environmental flows study, May 2007 Newsletter
09/2007 Daly River fish and flows project: an environmental flows study, September 2007 Newsletter
Type: Conference Participation
Titlesort icon Type
09/2009 Do food chain lengths in tropical floodplain rivers of northern Australia fit with expectations? Conference Participation
09/2009 Environmental flows case study in the Daly River Conference Participation
07/2009 Fine sediment sources in the largely undisturbed, tropical, low relief catchment of Darwin Harbour, Australia Conference Participation
09/2009 Fine-scale prioritization of fish persistence in the Daly River, NT: Condition and conservation re-revisited Conference Participation
09/2009 Food, flows and feathers: Riparian bird assemblages of Australia’s wet-dry tropics Conference Participation
09/2009 Impact of seasonal freshwater inflow on a benthic estuarine community Conference Participation
09/2009 Impacts of fish and nutrients on riverine primary production in a split stream experiment Conference Participation
05/2008 Isotopic fractionation and implications for stable isotope analysis of aquatic food webs. Conference Participation
05/2009 Landscape evolution and monsoonal ecology as drivers of phylogeographic patterns in north Australian freshwater fish Conference Participation
09/2009 Linking catchments to the coast - can the development of northern Australia negatively impact on the health and productivity of estuaries? Conference Participation
06/2009 Mercury in Northern Australian aquatic ecosystems Conference Participation
10/2008 Sources and fate of organic carbon in Australian streams and rivers. Conference Participation
09/2009 Spatial and temporal variation in density and diversity of flying aquatic and terrestrial insects Conference Participation
08/2009 Systematic conservation planning of eastern Australian rivers to manage and maintain bioregional variation in fish biodiversity Conference Participation
09/2009 The benefits of collaborative approaches to river research: Observations from the Daly River Fish and Flows project Conference Participation
09/2009 The evolutionary role of dendritic systems in structuring the fish populations of Australia’s northern rivers Conference Participation
09/2009 Two tales of fish: the value of multiple sources of knowledge for the assessment of environmental flow requirements of fish in the Daly River Conference Participation
2009 Urban-based nutrient inputs to Darwin Harbour - impacts on ecosystem functioning: AMSA Conference, Adelaide 2009 Conference Participation
Type: Book Chapter
Titlesort icon Type
Floodplains: Critically threatened ecosystems Book Chapter
Primary production in tropical rivers Book Chapter
Type: Magazine Article
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01/2010 Ground-breaking study into aquatic food web of our tropical river systems Magazine Article
01/2010 Ground-breaking study into aquatic food web of our tropical river systems Magazine Article
09/2009 The role of sediments in nutrient cycling in the tidal creeks of Darwin Harbour Magazine Article
Type: Journal Article
Titlesort icon Type
2008 Primary production and nutrients in a tropical macrotidal estuary, Darwin Harbour, Australia. Journal Article

 

our research themes

Theme 1: Scenario EvaluationTheme 2: Assets and ValuesTheme 3: River and Coastal SettingsTheme 4: Material BudgetsTheme 5: Foodwebs and BiodiversityTheme 6: Sustainable enterprisesTheme 7: Knowedge and Adoption

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