The boom-and-bust nature of much of Australia that is west of the Great Divide has never been more apparent than in the current conditions being experienced in the Murrumbidgee and Lachlan valleys in NSW.
Commonwealth Environmental Water Holder (CEWH) Dr Simon Banks said the wetter conditions parts of the country have experienced have seen waterbird populations boom, a positive response after their decline over the last 40 years. These wetter conditions enable waterbirds to breed up in large numbers and provide the next generation.
“Over 14 different waterbird species nested in the past 12 months, including all three ibis species, spoonbills, egrets, darters, cormorants and the Australian pelican,” Dr Banks said.
“Scientists and environmental water managers estimated that a total of more than 50,000 waterbirds nested in the Murrumbidgee valley and over 84,000 waterbirds in the Lachlan valley.
“An added bonus of increasing waterbird numbers is that these birds also feast on carp, which have also taken advantage of wetter conditions and have been causing damage to the local environment.”
Environmental water managers, such as the CEWH and NSW Department of Planning and Environment (DPE), worked with scientists to monitor the many breeding colonies that occurred in the Murrumbidgee and Lachlan valleys last summer. The period of 2021–22 was a very successful season for the Murray-Darling Basin’s feathered friends.
There are definite signs of even bigger breeding events occurring again this year, with waterbirds gathering in large numbers in local wetlands and on the floodplain.
Dr Kate Brandis from the University of New South Wales, who heads up the CEWH’s colonial waterbird monitoring program for the Murrumbidgee region, said abundant food and water since the wet period started in 2020, is the reason for this explosion of waterbird breeding.
“With lots of water everywhere, the boom-bust cued waterbirds know the wetlands of the Murrumbidgee and Lachlan valleys will supply enough food to hatch and fledge their chicks,” Dr Brandis said.
“Waterbird surveys over the last 40 years have shown an alarming decline in bird numbers. The prolonged wetter conditions we have been experiencing over the last two years has been a timely reprieve for Australian waterbirds populations.”
Protecting and restoring the natural environment involves collaboration and engagement from all sectors.
Dr Banks said environmental water managers, scientists and landholders work hard to protect and maintain suitable nesting habitats between and during natural flooding to maximise waterbird breeding success, maintain populations and conserve biodiversity.
“Water for the environment can be used to ‘top-up’ wetlands, maintain a steady water level and provide feeding areas to help sustain breeding conditions long enough for chicks to complete their growth stages, and finish what nature has begun,” Dr Banks said.
“Our native plants and animals have adapted to the boom-bust of Australia’s inland ecosystems. When times are good, and for waterbirds that’s during times of natural flooding or lots of water in the landscape, populations of plants and animals make the most of the increased resources.
“In dry times there isn’t enough food or water around, so these big breeding events that we are witnessing now just don’t occur.”
