Waterbirds in eastern Australia at lowest breeding level on record

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Waterbirds in eastern Australia at lowest breeding level on record

The annual aerial survey, conducted by the Centre for Ecosystem Science at the University of NSW, confirmed a dramatic long-term decline in the number of waterbirds

Director Richard Kingsford said that over 33 years of counting, average numbers had fallen more than 60 per cent.

The trend continued in 2015 with a further drop compared to the previous three-to-five-year period.

"This is the second lowest number of waterbirds we've seen in that 33-year period and it's symptomatic of the real impacts of this drought that's occurring across the eastern half of the continent," Professor Kingsford said.

The survey covered all the major rivers, lakes and wetlands from Queensland down through New South Wales, Victoria and South Australia, including the Murray-Darling Basin and the Riverina.

Birds unable to thrive

The team found the Macquarie Marshes and Lowbidgee wetlands were only partially filled, most rivers in the Murray-Darling Basin were also relatively dry, with little wetland habitat on their floodplains, and all the large lakes in the Menindee system were dry.

The Lake Eyre and Cooper Creek wetlands were mostly dry except for a small area to their east, while important wetlands in the Lake Eyre Basin including Lakes Galilee, Yamma Yamma, Torquinnie and Mumbleberry were dry.

Waterbirds were concentrated in relatively few important sites, with only four wetland systems holding more than 5,000 birds: Lake Killapaninna, Lake Allallina, Paroo overflow Lakes and Coolmunda Dam.

Most alarmingly, the total breeding index of all 50 species combined was the lowest on record and well below the long-term average.

Research fellow Kate Brandis said that without water swelling the wetlands, the birds were unable to thrive.

"Many of the waterbird species actually breed on vegetation that's been inundated by the water and so if there's not that nesting habitat where they feel safe then they don't breed," Dr Brandis said.

In fact, significant breeding was recorded in just one location.

Breeding species richness was also the lowest on record, with only black swans producing young, in low numbers.

"As we've seen over the long term with the aerial survey, we have a decline in waterbird numbers across the Basin and eastern half of Australia, so fewer breeding opportunities will only increase that decline," Dr Brandis said.

According to Professor Kingsford, it was not only the drought affecting water availability.

"The long-term decline in waterbird numbers we primarily see in the Murray-Darling is symptomatic of the over-allocation and river regulation, the building of dams and diversion of water that's occurred over that period," he said.

"Very often in the past we've considered our rivers as just pipes for delivering water for agricultural communities."

Source: ABC

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