One of Australia's most important wetlands is at serious risk, according to leading environmental scientist and Earthwatch principal investigator, Dr. David Paton, senior lecturer in the School of Environmental Sciences at the University of Adelaide. For over two decades, Paton has been monitoring waterbirds in the Coorong wetlands, at the mouth of the Murray River, South Australia; data collected in January 2004 by Earthwatch volunteers indicates that bird populations there are plummeting.
"Numbers are down for all bird species from last year, with three species of real concern," said Paton. "Fairy tern numbers this year were 150 compared with 400 last year and over 1,500 in the 1980s. Curlew sandpipers were less than 2,000, slightly down on last year but in the 1980s they numbered 40,000. There were less than 1,000 red-capped plovers, for the second time in the last three years."
The cause of the population crash is clear: reduced and altered flows in the Murray-Darling River system. Less than 27 percent of the Murray's water now reaches the river mouth, due to diversions for agriculture and other uses upstream. With less water reaching the river's mouth, some areas are blocked and must be dredged to keep them open. Overall, there is less mixing of tidal ocean waters and river water, and the area of wetlands and tidal flats has decreased dramatically.
For wetland birds, this means less food, in the form of worms, molluscs, and other wetland invertebrates, reflected by decreasing numbers of birds using the northern Coorong. The area can no longer support the approximately 100,000 birds that flocked to this area in the 1980s, some of them migrating thousands of miles each year from breeding grounds in the northern hemisphere.
"While environmental flows of water down the river continue to be compromised by human use of the water, the northern Coorong is likely to continue to deteriorate," said Paton.
Another major impact on the Coorong system is the release of large volumes of "fresh" water as part of a massive regional drainage scheme to alleviate the impacts of dry land salinization on agricultural production in eastern South Australia. The added water tends to further reduce the extent of tidal mudflats so important to wading birds.
"This will change the hyper-marine nature of the southern Coorong, potentially creating an estuarine lagoon, further impacting bird populations, and will embarrass Australia internationally," said Paton. The Coorong wetands are supposed to be protected under an international treaty, the Convention on Wetlands, also known as the Ramsar Convention, to which Australia was the first signatory in 1971. "Australia has an international obligation to manage this wetland system wisely," added Paton.
"There is an opportunity for Australia to listen to the science and to take positive action to reverse habitat declines to ensure a future for our coastal wetlands and for the birds that are dependent on them," says Earthwatch Australia Executive Director Dr. Jane Gilmour.
For information on volunteering on the Waterbirds of the Coorong project, click here
Earthwatch Institute is an international nonprofit organization which supports scientific field research worldwide by offering members of the public unique opportunities to work alongside leading field scientists and researchers. The Institute's mission is to engage people worldwide in scientific field research and education to promote the understanding and action necessary for a sustainable environment.