Theme 5: Foodwebs and biodiversity

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

Leader:

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

Leader:

Prof 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

Leader:

Prof 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

Leader:

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

Leader:

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

Leader:

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)

Leader:

Peter Davies

Brad Pusey

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

Leader:

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.

5.9: Northern Australia Aquatic Ecological Assets

Leader:

Mark Kennard

The Northern Australia Water Futures Assessment (NAWFA) is an Australian Government initiative to provide the science needed for sustainable development and protection of Northern Australia’s water resources. One project being undertaken as part of the NAWFA Ecological Program is the TRaCK Northern Australia Ecological Assets Project.

Publications

Corporate publication
	Title
	A bibliography of material dealing with the aquatic biodiversity of northern Australia, threats and impacts, and management	Corporate publication
10/2009	Aquatic ecosystems in northern Australia	Corporate publication
01/2011	Bibliography of source material concerning freshwater fish distributions across northern Australia	Corporate publication
11/2011	Field Manual - Including protocols for quantitative sampling of fish assemblages, habitat, water quality and sample preservation.	Corporate publication

Journal Article
	Title
01/2011	A non-lethal sampling method for stable carbon and nitrogen isotope studies of tropical fishes	Journal Article
07/2010	An integrated risk assessment for climate change: analysing the vulnerability of sharks and rays on Australia's Great Barrier Reef.	Journal Article
	Bayesian network models for environmental flow decision making in the Daly River, Northern Territory, Australia	Journal Article
12/2010	Biogeochemical implications of climate change for tropical rivers and floodplains	Journal Article
02/2011	Challenges and Opportunities in Implementing Managed Relocation for Conservation of Freshwater Species	Journal Article
03/2010	Climate Change Implications for River Restoration in Global Biodiversity Hotspots	Journal Article
05/2010	Conservation biogeography of freshwater fishes: recent progress and future challenges	Journal Article
09/2010	Historical population connectivity and fragmentation in a tropical freshwater fish with a disjunct distribution (pennyfish, Denariusa bandata).	Journal Article
	Landscape genetic analysis of the tropical freshwater fish Mogurnda mogurnda (Eleotridae) in a monsoonal river basin: importance of hydrographic factors and population history	Journal Article
04/2010	Northern Australia, whither the mercury?	Journal Article
2008	Primary production and nutrients in a tropical macrotidal estuary, Darwin Harbour, Australia.	Journal Article
11/2011	The “wet-dry” in the wet-dry tropics drives river ecosystem structure and processes in northern Australia.	Journal Article

Presentation
	Title
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 - (Project Workshop, Darwin, June 2008)	Presentation
09/2009	Ecological watering requirements in northern Australia, Riversymposium Conference, Brisbane 2009	Presentation
12/2008	Environmental flows for northern Australian river and estuaries, Coast 2 Coast Conference, Darwin 2008	Presentation
October 2008	Environmental flows for northern Australian rivers and estuaries, ASL Conference, 2008	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, Darwin 2008	Presentation
08/2008	Seasonal contrasts in carbon budgets and ecological processes on a tropical floodplain river in Northern Australia, Coast 2 Coast Conference, Darwin 2008	Presentation
July 2009	Seasonal contrasts in carbon budgets on a tropical river floodplain, International Society for River Science Congress, Florida USA, July 2009	Presentation
July 2009	Spatial variation in aquatic food web structure across tropical riverine landscapes, International Society of River Science Congress, Florida USA, July 2009	Presentation
09/2009	The significance of water flows for estuaries, Riversymposium Conference, Brisbane 2009	Presentation

Book
	Title
	Aquatic Biodiversity in Northern Australia: patterns, threats and future	Book

Magazine Article
	Title
11/2010	Big Floods = Big Barras	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

Report
	Title
09/2009	Biogeochemical processes and sewage markers in Buffalo Creek, Darwin	Report
12/2010	Flow and fisheries: River impacts on estuarine prawns in the Gulf of Carpentaria	Report
07/2010	Identifying high conservation value aquatic ecosystems in northern Australia	Report
02/2011	Priorities for identification and sustainable management of high conservation value aquatic ecosystems in northern Australia	Report

Conference Participation
	Title
06/2010	Colonization and Use of Dry Stream Beds by Terrestrial Invertebrates	Conference Participation
06/2010	Context Dependency in Periphton and Invertebrates: Interactions between Velocity and Nutrients in the Australian Wet-Dry Tropics	Conference Participation
09/2009	Do food chain lengths in tropical floodplain rivers of northern Australia fit with expectations?	Conference Participation
07/2010	Dynamics of Aggregated River Wood and Importance as Fish Habitat in a Tropical Australian River	Conference Participation
07/2010	Environmental Filters Determine Strong Spatial Concordance among Multiple Species in Tropical Australian Riverscapes	Conference Participation
09/2009	Environmental flows case study in the Daly River	Conference Participation
07/2010	Extreme conditions structure meiofauna communities in the arid tropics of Australia	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
06/2010	How are biogeochemical processes differentially affected by nutrient loading?	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
06/2010	Key drivers of river and wetland food webs in Australia’s Wet Dry Tropics	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
06/2010	Major Solute Chemistry as an Indicator of Hydrology in Tropical Floodplains	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
06/2010	The Rainbow Connection: An integrative approach to identifying melanotaeniid (Melanotaenia splendida inornata) dispersal in response to flooding.	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

Newsletter
	Title
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

Book Chapter
	Title
	Floodplains: Critically threatened ecosystems	Book Chapter
	Primary production in tropical rivers	Book Chapter

Artwork
	Title
	Majalin Guwardagan-guna (Lahan Wagiman). Fish from Daly River (Wagiman country)	Artwork

Audiovisual
	Title
	TRaCK researchers contribute to the ABC Rivers project	Audiovisual

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Theme 5: Foodwebs and biodiversity

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