The waterbird population across eastern Australia has plunged dramatically, with recent reports indicating a startling 50.4% decline within just one year. According to the University of New South Wales (UNSW), the latest annual survey conducted from August to October 2024 identified only 287,231 waterbirds, significantly down from 579,641 birds recorded in the previous year.
This annual survey, which has been carried out since 1983, provides one of the most important insights available on the health of biodiversity across the river and wetland ecosystems. Covering approximately one-third of the Australian mainland, the data collected is invaluable for assessing not only the numbers of waterbirds but also the overall health of their habitats.
Professor Richard Kingsford, who leads the survey, explained the worrying trend, linking the drastic reduction of waterbirds to the increasingly dry conditions affecting breeding success. "We know when it starts to dry up, the floodplains dry up and waterbirds do not have the food to breed in large numbers..." he stated. The scarcity of adequate breeding conditions results from the natural drying out of habitats following two years of unprecedented floods experienced throughout 2021 and 2022.
After the advantageous breeding cycles triggered by wet years, Kingsford noted, "We had a good bounce in numbers after good breeding... but numbers have now dipped below the long-term average again..." The results reflect long-term declines, with overall breeding numbers reducing sharply since 2023.
The survey also revealed concerning indicators related to the size and health of wetlands, reporting the overall wetland area to be just 122,283 hectares—significantly below the long-term average for the region. Key wetland areas such as the Georgina-Diamantina River system exhibited the highest abundances, yet still saw worrying reductions.
These changes cannot be separated from the broader climatic conditions affecting eastern Australia. Increasingly dry weather patterns driven by climate change have resulted in "a decrease in April to October rainfall of around 9% since 1994," as Kingsford explained. Such shifts have had serious ramifications for water flows across the entire nation, particularly visible within the critically important Murray-Darling Basin.
Dr. John Porter, Senior Scientist at DCCEEW, confirmed the negative impact these drier conditions continue to have on waterbird populations, noting, "These drier conditions always affect breeding of waterbirds..." The continued decline of breeding figures signals the need for urgent remediation efforts aimed at preserving these natural ecosystems.
While this year's numbers place the data roughly at the midpoint of the survey's 42-year history, the findings still warrant caution. This year, only sporadic breeding efforts were recorded across the surveyed areas, including just some rookeries belonging to species such as the cattle egret and Australian white ibis. This decline indicates not just short-term repercussions but also potential long-term effects on the ecological balance within these environments.
The findings from this survey are particularly alarming as the changing conditions denote not just the peril facing waterbirds but also signal broader ecological distress within Australia's wetlands. With waterbird populations serving as important indicators of ecological health, the trends observed provide valuable insight and call for proactive measures to be enacted.
Waterbird health is intricately linked to the condition of wetlands, which are susceptible to both climatic shifts and human impacts. Understanding this interdependence is necessary for protection and mitigation strategies as scientists continue to track these populations.
Ongoing assessments will be key to grasping the full scope of the challenges facing waterbirds and their habitats. Without intervention and recognition of these trends, Australia's unique biodiversity could face dire consequences—further emphasizing the necessity for sustainable and adaptive management practices aimed at preserving these fragile ecosystems.
