Ecologist David Paton has been counting bird numbers annually since 1985 in the lagoons and wetlands that make up the Coorong system in South Australia, and his latest count concerns him.
His summer survey has confirmed a finding the Murray-Darling Basin Authority came up with last year — that international migratory shorebird numbers in the Coorong and Lower Lakes at the mouth of the Murray are at their lowest recorded levels.
The Associate Professor from the University of Adelaide said dense algae had made it difficult for shorebirds and for the vegetation they normally fed on to grow.
“Filamentous green algae has never been here except for the last few years,” Dr Paton said.
“That’s now so abundant it’s causing problems for some of those migratory shorebirds and their food supply.”
Black-winged stilts, sharp-tailed sandpipers and red-capped plovers are among species which migrate many thousands of kilometres from China, Korea and Japan to their summer home in Australian wetlands.
The Coorong is an internationally recognised Ramsar site, which legally obliges Australia to maintain the habitat.
It is five years since the introduction of the Murray-Darling Basin Plan, which is aimed to overcoming decades of mismanagement and reduced water flows down the Murray.
“China and Japan and Republic of Korea would be horrified to think that Australia is just ignoring these international agreements that we’ve signed with them saying we’ll look after the habitats of these shorebirds,” Dr Paton said.
“The damage might well have been done to this international wetland.
“This might not be able to be removed now and it’s a great shame. We have these so-called pieces of legislation and both state and federal governments ignore it when it comes to looking after an asset that’s this important for migratory shorebirds.”
Dr Paton is also pointing the finger at the South East Flows Restoration Project, funded with $60 million of state and federal money, which is channelling drainage water from farms into the southern Coorong.
Science ‘rejects’ nutrients concern
SA Environment Department head of River Murray operations Andrew Beal said scientific evidence discounted Dr Paton’s theory which blamed nutrients from the drains.
“Recent findings by the Adelaide University have concluded that there’s a net export of nutrients by introducing that water — it has both a diluting and exporting effect, which in the total scheme of things is a positive thing,” Mr Beal said.
He said the project was importantly keeping Coorong salinity levels in check and boosting the system when flows from the Murray became too low.
“It will never go back to its original pristine condition, but I think we can have a very healthy Coorong and Lower Lakes, albeit it’s going to take time because the condition that the system was in at the end of the millennium drought was severely degraded,” Mr Beal said.
The Murray-Darling Basin Authority told the ABC tthe Basin Plan was never going to deliver overnight results, but it remained confident conditions would improve in the Coorong in the years ahead.
“It will take time to turn around long-term trends like this, but the Basin Plan remains our best chance of securing a sustainable future for the Murray-Darling Basin’s diverse flora and fauna,” an authority spokesperson said.
“By 2019, we are aiming to see populations of key shorebird species maintained.”
Dr Paton will return to count the birds again next year.
“If there’s no way of removing this algae from the system and no way of fixing that water level then I think we seriously have to think about alternative ways in which we can serve our obligation, our international obligation, to migratory shorebirds that come to this country [and] depend on this place for their summer.”