With a bright yellow stripe stretching from their nose to the tip of their tail, these striking turtles are hard to miss.
The Manning River turtle is found nowhere else on earth except for the few coastal rivers in New South Wales’ Manning River region. Known as Guraa in the Gathang language of the Traditional Custodians of Birpai-Barray, this ancient turtle has a lineage dating back 55 million years.
However, this ancient species faces a very modern crisis. The Manning River turtle is listed as endangered and is being pushed towards extinction by the pressures of habitat clearing, the illegal pet trade and invasive predators that prey on adult female turtles and their eggs.
But as our new study reveals, this species faces an even more urgent, and perhaps unexpected, threat: another native but locally-introduced turtle.
The Macquarie River turtle (Emydura macquarii), also known as the Murray River turtle, is native to several river systems snaking across Australia. It is also listed as critically endangered in Victoria and vulnerable in South Australia.
However, this species is spreading beyond its natural range. Macquarie River turtles were first found in NSW’s Manning River catchment in 2007, and were possibly introduced by people releasing their pet turtles into the river. These turtles have now been detected across nine different tributaries in the Manning River and are continuing to spread.
Macquarie River turtles are a threat to populations of the critically endangered Bellinger River turtle (Myuchelys georgesi) and the endangered Manning River turtle. These two species are only found in two coastal river systems in eastern Australia. Macquarie River turtles compete with these native species for resources such as food. They can also harbour disease such as the Bellinger River virus.
Hybridisation is perhaps the most pressing threat. Hybridisation occurs when different species breed and produce hybrid offspring. Research suggests it is not a new phenomenon among Australia’s freshwater turtles. However, hybridisation can lead to the loss of distinct species, when hybrid animals rapidly reproduce and eventually replace the endangered population.
Current evidence suggests hybridisation is already occurring in the Bellinger and Kalang Rivers, where the Macquarie River turtle was introduced in the 1990s.
The native Macquarie River turtle (Emydura macquarii) is now found in the Manning, Bellinger and Kalang Rivers.Ricky Spencer/1 Million Turtles
All in a drop of water
Thankfully, Macquarie River turtles have not yet expanded across the entire Manning River. So tracking their spread is vital to protecting other native turtles.
Currently, turtle ecologists can detect turtles by snorkelling or trapping. They can also observe their behaviour through underwater video surveys. However, these methods can be time consuming and costly, and in some cases mean turtles are handled by humans.
Our new study investigated how else we could monitor the presence of Macquarie River turtles, particularly as they encroach on the Manning River turtle’s habitat.
Specifically, we developed highly sensitive and species-specific environmental DNA tests. When turtles swim through rivers they leave behind traces of their DNA – known as eDNA – that scientists can detect using eDNA tests.
We designed these turtle tests in the lab. We then compared the DNA sequences of our target turtle species with other turtle species that are closely related or live in the same habitat. This ensured our tests were specific to the Manning River and Macquarie River turtles. This matters because river water can contain the DNA of hundreds or even thousands of different species.
We then took water samples from five locations across the Manning River catchment over a period of three days. We did this to see if the eDNA tests could detect the DNA turtles shed into river water. Using a portable eDNA backpack – which filters water from the river to capture DNA – we were able to sample litres of water in minutes while preserving the DNA we collected.
Meanwhile, turtle ecologists from the Redleaf Group, an Australian environmental company, took to the river with mask and snorkel. They physically captured turtles present in the river and recorded important population data.
Results from the snorkelling surveys and our eDNA tests were consistent. Both methods detected Manning River turtles at all five locations but no introduced Macquarie River turtles. However, more research is needed before we can conclusively say Macquarie River turtles were not present at these sites.
We hope these eDNA tests will help researchers accurately track the spread of turtle species outside their natural ranges.
eDNA tests are valuable because of their versatility. They can be used to pinpoint areas where a target species is present, allowing ecologists to then gather population data using traditional survey methods like trapping and snorkeling. They can also be used to identify broader trends about the distribution of a target species.
Dr Jessica Tout-Lyon with an eDNA backpack, sampling river water in the Manning River catchment.Aunty Yvonne Harvey
eDNA surveys can act as a powerful citizen science tool. Their straightforward application allows members of the community to collect water samples and contribute to local conservation efforts. These surveys can complement other citizen science projects such as 1 Million Turtles and TurtleSAT, which allow the public to record turtle sightings.
Australians are accustomed to the threats of introduced species from overseas. But as the Macquarie River turtle shows, native species in the wrong locations can also put additional pressure on our already endangered species.
Jessica Tout-Lyon receives funding from the MidCoast Council and the New South Wales Department of Climate Change, Energy, the Environment and Water. She is affiliated with the Manning River Helmeted Turtle Steering Committee.
Elise Furlan is Director of Science and Research at NatureDNA. She receives funding from the MidCoast Council and New South Wales Department of Climate Change, Energy, the Environment and Water.
Louise Streeting is affiliated with the University of New England and is involved in the Turtles Forever conservation program funded by Local Land Services.
Mathew Bell is employed by MidCoast Council, which receives grant funding from external sources including from the New South Wales and Commonwealth governments. He is affiliated with the Manning River Helmeted Turtle Steering Committee.
The next few months will help determine whether New Zealand has successfully eradicated the yellow-legged hornet, one of the world’s most damaging invasive pests.
The government invested more than NZ$12 million in the effort to find and destroy every last hornet.
Encouragingly, the last known nest was detected in late March and extensive winter surveillance, including trapping, and the monitoring of beehives failed to find any evidence that hornets remain.
There is cautious optimism at the Ministry of Primary Industries (MPI) and members of the technical advisory group that eradication was successful.
But the real test of success is about to begin, and it depends on ensuring no queens that may have survived the winter escape detection.
As our research shows, honey bees were a major component of the yellow-legged hornets’ diet and even a single surviving queen could set off a new incursion, with potentially devastating consequences for beekeepers.
Any surviving queens will be emerging now
If any queens survived the winter undetected, they are likely to start waking from hibernation now.
This is a critical stage in the hornet’s life cycle. Each autumn, a nest produces new queens that mate, store sperm and spend winter hidden away in sheltered locations. In spring, those queens emerge alone and begin the task of building a new nest.
At first, the nest is surprisingly small. Often hidden under house eaves, in hedges or among shrubs, an embryo nest may be no larger than a tennis ball. The queen must do everything herself – collecting food, building the nest and raising the first generation of young.
For a brief window, the future of an entire colony depends on this single insect.
If the queen succeeds, her first workers take over foraging duties and the colony begins to grow rapidly. The nest may reach the size of a coconut before the hornets relocate to a much larger nest, often high in the canopy of a tree. By late summer, a mature colony can contain thousands of hornets.
This is why spring is such an important time for surveillance. A single survivor could allow hornets to establish and become widespread in New Zealand.
Hornets eat a lot of honey bees
We’ve recently completed a preliminary analysis of what yellow-legged hornets were eating in Auckland, and the results highlight why eradication is so important.
Each and every hornet larva we analysed was fed honey bees. The adult hornets that feed the larvae were not occasional bee predators – they were regular bee hunters. Overall, almost one-third (31%) of the hornet diet appeared to consist of honey bees.
If these hornets had established across New Zealand, beekeepers would have faced a very different future. That future would not only affect beekeepers but have consequences for pollination of crops such as kiwifruit, avocados and many other horticultural and agricultural products.
To understand what the hornets were eating, we analysed DNA found in hornet larval faeces. The larvae deposit their waste in the base of the nest cells, creating a biological record of what the adult hornets had been hunting and feeding to their young.
The results revealed a remarkably broad diet. In total, we detected evidence of 77 different animal taxa. Alongside honey bees, the hornets regularly preyed on flies, cicadas and even common and German wasps.
We also found DNA from blackbirds, mice and sheep. These species were unlikely to have been hunted and were probably scavenged from carcasses.
The hornets also made extensive use of New Zealand plants. We found evidence they collected nectar from a wide range of species, including m?nuka and camellia.
DNA recovered from nest material suggests they were constructing nests using fibres from plants such as k?nuka, t?tara and poplar, among many others.
77 queens captured
The early discovery and quick action to destroy the yellow-legged hornet nests in Auckland may have prevented a widespread population explosion that would have been extremely difficult to reverse.
Between October 2025 and March 2026, a total of 77 queens were captured. We believe those queens were likely the offspring of a single nest that had survived from the previous season.
At first glance, 77 queens may not sound like many. But if those 77 queens had survived, established nests and each produced 77 more queens, by now there could be almost 6,000 new queens waking from hibernation. Eradication would have been near impossible.
If they had established throughout New Zealand, I have no doubt honey bees and beekeepers would have suffered significant impacts. Since honey bees are important pollinators, protecting them means protecting the infrastructure that underpins New Zealand’s food production.
One of the most important lessons from hornet incursions elsewhere is that the public can play a crucial role in finding and eliminating invasive pests. Overseas eradication programmes sometimes encourage “spring queening” to catch queens before they can establish a colony.
If any queens survived the winter, finding them now could prevent a new generation of hornet nests from becoming established and spreading across New Zealand.
Over the past year, MPI received more than 18,200 suspected hornet reports from members of the public. That extraordinary response helped define the boundaries of the infestation, supported surveillance efforts and contributed to the search for nests.
MPI is asking people who sees anything that looks even remotely like a yellow-legged hornet to report it immediately to 0800 809 966 or via the online reporting form. Beekeepers and members of the public can find more information and guidance on hornet surveillance and trapping on the MPI website.
Phil Lester serves on the Technical Advisory Group for the Ministry for Primary Industries' hornet response.
Irrigators and One Nation are calling for environmental water in the Murray-Darling Basin to be made available for agricultural production this season.
More than half the wood removed under WA’s trial of ecological thinning is being chipped, burned or exported overseas, according to information revealed in state parliament.
Prime ministers of Australia and Iceland discuss effects on their countries even as some shy away in face of war and inflation
World political leaders are descending on New York for the UN general assembly and some of them are putting the climate crisis on the agenda as they spoke on Monday at the start of the city’s annual Climate Week.
This year’s Climate Week – which runs alongside UNGA – comes after months of extreme heat in large parts of the world including Europe and the US, wildfires in Africa, flash flooding in Asia and a record-breaking El Niño.
