Watering floodplain wetlands in the Murray-Darling Basin for native fish
Waterlines report 56 - September 2011
The Watering floodplain wetlands in the Murray-Darling Basin for native fish Waterlines report was launched at the Commission's Managing Wetlands Workshop held in Canberra on Tuesday 6 September 2011.
The research, which was undertaken by the Murray-Darling Freshwater Research Centre (MDFRC) in collaboration with the Arthur Rylah Institute (ARI), delivered the following products to assist wetland managers, water planners and policy makers in making decisions on water regimes that will benefit native fish populations:
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Waterlines report: The Watering floodplain wetlands in the Murray-Darling Basin for native fish (Beesley L, Price A, King A, Gawne B, Nielsen D, Koehn J, Meredith S, Vilizzi L, Ning N, Hladyz S) report presents a summary of key findings, key messages, recommendations and science from the project work. It also includes monitoring protocols that could be used by those undertaking environmental watering.
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Decision Support Tool: The Fish-in-Wetlands Decision Support Tool (FWDST) using Bayesian network models for three native species-golden perch, Australian smelt and carp gudgeon-and one alien fish, common carp. The tool helps managers to compare the likely outcomes of different watering scenarios for the four species based on attributes of watering and wetland characteristics. By considering a range of native and alien fish species, the FWDST aims to provide managers with a probabilistic assessment of fish population responses to a number of different wetland watering strategies so that they may be compared. This tool is available on the MDFRC website: www.mdfrc.org.au
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Demonstration wetland: The MDFRC and ARI have worked with all relevant stakeholders including the NSW Office of Environment and Heritage, the NSW Department of Industry and Investment (Fisheries), NSW State Water, the Murrumbidgee CMA, and the Wiradjuri people to develop Coonancoocabil lagoon on the lower Murrumbidgee River, NSW as a demonstration site. This demonstration site will facilitate the ongoing development and refinement of the decision support tool.
This three-year project is one of only a few studies that have investigated the fine-scale relationships between the application of environmental water (i.e. timing, magnitude, duration, method of delivery, and frequency of delivery), wetland habitat characteristics, and the fish community. This project examined the water needs of fish in off-river wetlands for four typical fish species, (three native species-golden perch, Australian smelt and carp gudgeon-and one alien fish, common carp) and how to deliver the water to maximise species management.
Early and on-going collaboration with stakeholders to help shape and inform the design of science and the project outputs was critical to the success of this project.
Coonancoocabil Lagoon NSW. Photo A. Brecknell (National Water Commission).
Key findings are:
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Watering 'attributes' are critical to optimising fish abundance in wetlands because they affect the colonising potential of fish (method of water delivery, source water) and their ability to successfully spawn and recruit (timing of watering).
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The delivery of environmental water should be a focus of restoration efforts aimed at improving native fish outcomes in floodplain wetlands. The role of habitat in influencing fish community response assumes more importance when wetlands are watered naturally (i.e. not through artificial management infrastructure)
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Fish-related targets for wetland watering need however to be carefully defined since the importance of watering and habitat attributes to fish abundance varies among species. If the target is specifically aimed at an individual species, managers will need an awareness of its species biology and ecological requirements.
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The inherent variability of wetlands and watering events means that fish-related targets for wetland watering should be reviewed, and adapted if required, before each artificial watering event to ensure that the target is achievable.
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If a target of wetland watering is to increase long-term native fish abundance, fish need a secondary watering event (eg top-up watering) to move into the river. Severe wetland shrinkage post-watering should be avoided.
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The fish communities inhabiting floodplain wetlands are spatially and temporally diverse - with this in mind managers may want to minimise reliance on a limited number of iconic wetlands to achieve conservation goals.
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Scientist/water manager collaboration is important to maximise native fish benefits from environmental watering.
Documents for download
Watering floodplain wetlands in the Murray-Darling Basin for native fish PDF (3.89MB)