Long-term study in Australian wetlands

Long-term study of Murray-Darling Basin and Lake Eyre Basin wetlands

reveals severe impact of dams and water diversions

A landmark 30-year-long UNSW study of wetlands in eastern Australia found that construction of dams and diversion of water from the Murray-Darling Basin have led to a more than 70 per cent decline in waterbird numbers. This was primarily due to severe degradation in the basin resulting from reduced water flow. The study is published in the journal Global Change Biology.

For 32 years (1983-2014), the survey team analysed data from annual aerial surveys of waterbirds in an area covering almost a third of the continent (see map). They surveyed up to nearly a thousand wetlands, along each of 30km wide survey bands (see map) every October counting individual species.

Outcomes

Waterbirds declined at all spatial scales in the Murray-Darling Basin: the basin scale, the river scale and the wetland scale. In stark contrast, there were no trends at any of these scales in the Lake Eyre Basin. They found that about a quarter of all species of waterbirds declined in the Murray-Darling Basin. This decline was reflected in reductions in numbers of fish-eating, plant eating and invertebrate feeding waterbirds, reflecting major declines in river ecosystems. The team also showed that waterbird numbers were directly related to reduced river flows and inundation of wetlands. This directly linked the long-term decline to the development of the rivers of the Murray-Darling Basin, with its more than 240 dams that store almost 30,000 gigalitres of water, compared to minimal development in the Lake Eyre Basin. This development has impacted severely on natural flooding of wetlands.

Recommendations

The study has significant implications for environmental flow management in the Murray-Darling Basin. It also showed the importance of environmental flows for the restoration or rivers and wetland health. The team showed there was nearly a 20% bounce back in numbers of waterbirds if the current environmental flow target is met, but this could easily be lost without policies that adequately manage impacts of climate change. There are also major warning signs for the development of the rivers of northern Australia and other rivers around the world. Development of rivers has major impacts on environmental values which also translate into effects on fish species, estuaries, values of traditional owners and floodplain grazing communities.

 

Full details of the study

Kingsford, R.T., Bino, G. and Porter, J.L. (2017). Continental impacts of water development on waterbirds, contrasting two Australian river basins: Global implications for sustainable water use. Global Change Biology, http://onlinelibrary.wiley.com/doi/10.1111/gcb.13743/epdf

Also check out the recent media coverage: http://www.abc.net.au/news/2017-06-05/murray-darling-basin-waterbirds-population-declining/8587720 

Project: 
Waterbirds of the Macquarie Marshes
Waterbirds - Sentinels of environmental flow in the Murray-Darling Basin?
Eastern Australian Waterbird Survey
Research Programs: 
Waterbirds
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