The populations of the Australian crane (Antigone rubicunda) in the southern and northern parts of Australia show significant genetic differences, and the population in Victoria, in the country’s southeast, faces an increased risk of loss of genetic diversity. The conclusion results from a study led by Macquarie University, which used feather samples collected by citizen scientists and researchers.
The team analyzed DNA from feathers collected between 2009 and 2023 and identified two distinct genetic groups. One corresponded to the birds from Victoria, while the other brought together individuals from New South Wales, Queensland and the Northern Territory.
According to the researchers, this differentiation results from lower gene flow between the Victoria populations and the more northern regions. One reason is related to the different breeding periods: the birds begin nesting after rains fill the wetlands, which happens in winter and spring in the temperate southern regions and in summer and autumn in the tropical northern regions.
The difference in breeding periods reduces opportunities for interbreeding between the populations. The effect is particularly relevant for the southern population, which is much smaller. Recent estimates point to fewer than a thousand adults in that population, while the northern population, distributed across Queensland, the Northern Territory and Western Australia, may number between 50,000 and 100,000 individuals.
The researchers simulated different scenarios of population decline and concluded that the southern genetic group, concentrated mainly in the western part of Victoria, faces a greater risk of losing genetic diversity.
Nevertheless, the analysis indicates that the northern population, although much larger, also remains vulnerable to threats such as habitat degradation.
Australian cranes depend on wetlands to nest and rest during the breeding periods and outside of them, although they also seek food in other habitats. In Australia, urban expansion, agriculture and climate change have contributed to the degradation and loss of wetlands.
Field observations and follow-up studies conducted in Victoria also show that these birds tend to return to the same wetlands to breed and to form flocks year after year.
“The tendency of Australian cranes to return to the same wetlands to breed demonstrates the importance of protecting and restoring these wetlands and maintaining connectivity among them, in order to help preserve the species’ genetic diversity,” says Abby Bryce, a doctoral researcher and the study’s lead author.
The researcher warns that a new loss of wetlands could have lasting consequences for the Australian cranes in western Victoria.
The study, published in the journal Conservation Genetics, also drew on contributions from citizens who participated in the Feather Map of Australia project, through feather collection and submission and the identification of locations used by the birds for feeding and flock formation.
