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High up in an ancient conifer rainforest, at what was once the largest Indigenous gathering place in eastern Australia, there is sunlight where there shouldn’t be.
Among the eponymous pine trees of the Bunya Mountains, in south-east Queensland, a deadly disease has taken root. Walking through the forest, Adrian Bauwens, a Wakka Wakka man, says pockets of sunlight have replaced what is “usually quite a dense canopy where’s it’s quite heavily shaded”.
The towering bunya pines are afflicted by a plant pathogen known as dieback and becoming skeletal, dropping their leaves and limbs. The culprit is Phytophthora, a type of water mould that spreads through soil and attaches itself to the roots of trees, cutting off nutrient and water supply.
Bunya dieback has been an issue over the past decade, but its spread is being worsened by a porcine threat. Feral pigs are “running quite wild”, Bauwens says; “trotting around in dieback areas … spreading it through the mountain by digging it up”.
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The destructive invasive species use walking tracks and bike trials in the national park as “highways”, attracted by the promise of food in the bunya’s large nut-filled pine cones. “The major draw card for them is when the nuts are fruiting,” Bauwen says. “They pretty much hit every tree they can.”
A forest health officer at the Bunya Peoples’ Aboriginal Corporation, Bauwen is concerned for the fate of trees, which have been described as “living fossils” and are thought to date back 145m years to the Jurassic period.
“[It] is a culturally significant tree to us,” he says. Thousands of Indigenous Australians of different tribes once travelled long distances to converge on the Bunya Mountains, to visit and celebrate the pines. “It acted as a bit of a parliament house, where tribal disputes, marriages and ceremonies took place,” Bauwen says.
Feral pigs, Sus scrofa, originate from the arrival of the First Fleet and have since spread across 45% of Australia, with higher concentration in the country’s north-east. According to a 2020 estimate, the pests numbered between 2.4 and 4 million nationally, though experts say the true number is likely far higher now. Three years of favourable weather have resulted in booming pig populations, which has conservationists and Indigenous traditional custodians sounding the alarm to avoid further damage to ecologically and culturally significant sites.
‘Severe ecological imbalances’
Because of heavy rainfall that has yielded high nutrient loads, the scale of the feral pig problem is “much higher than what has been experienced at any point before”, says Reece Pianta, advocacy director at the Invasive Species Council. “Australian landscapes didn’t evolve for hard-hoofed animals and aggressive foragers with the mass of a feral pig … we are seeing severe ecological imbalances starting to occur.”
Pianta says the council is increasingly receiving reports of pigs foraging at sea turtle nesting grounds – in places such as western Cape York and Bribie Island – and eating eggs and hatchlings.
In the Northern Territory, feral pigs have become a staple part of the diet of the saltwater crocodile, helping to drive a rebound in the reptile’s population over the last 50 years. The Top End croc population consumes about six feral pigs per sq km of wetland floodplain annually, research estimates.
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But Euan Ritchie, a professor of wildlife ecology and conservation at Deakin University, says it is unclear whether crocodiles can have a meaningful effect on keeping pig numbers down. “The problem with pigs is … they’re really widespread, they’re quite adaptable animals and they can breed really rapidly,” he says.
Their threats are myriad. By digging up soil while searching for food, pigs contribute carbon dioxide emissions and spread diseases and weeds. They can wreak havoc in ephemeral wetlands and waterways, resulting in erosion and water quality issues.
Alfred Hunter, a Djabugay Bulmba ranger in far north Queensland, has noted feral pig damage to platypus habitat. In a project with WWF Australia earlier this year, rangers identified platypuses in waterways near the town of Kuranda for the first time in decades, after fears the monotremes had become locally extinct.
But they were concerned about the presence of feral pigs, which “dig along the sides of the riverbanks and creekbanks” and had been spotted on trail cameras, Hunter says. “Platypuses normally nest underneath the bank.”
“It’s not just the river systems,” he says. Parks, campgrounds and sacred sites are “getting ripped to shreds”.
Farther north, the devastating impacts of feral pigs have long been obvious to Trevor Meldrum, a Kuuku Yalangi man and an environmental operations manager at Cape York Weeds and Feral Animals. “You’ve got our rock art painting sites that are being rubbed right through – the paint’s gone. Their excrement and the salts in their skin erode a lot of those sacred places,” he says.
“We’ve got wetlands … that used to be waste deep when we were kids. Some of them will only come up to your ankles now”. The pigs, he says, are “the main destroyers.”
Ritchie believes it is “probably unrealistic, unfortunately” to expect that pigs can be eradicated from large areas. “What we’ll have to do is be more strategic about areas that might be of particular concern.”
Control methods include shooting, trapping, and targeted poisoning. While private hunting can also remove pigs from the population – donations of carcasses to crocodile farms have occurred in the past – in the US, bounty programs have not helped eradicate the animals.
“Effective feral pig control needs to be professional and humane and done at a landscape scale,” Pianta says. “We know that to achieve pig population reduction, you need to remove greater than 70% of their number each year.” He points to a $2m Queensland government investment in addressing the state’s feral pig problem as a step in the right direction.
But Meldrum would like to see urgent investment in the northernmost part of the country, to equip Indigenous owners on the Cape York peninsula with the resources to tackle the invasive pig issue before it worsens. “We care about our country,” Meldrum says. “Prevention is better than cure any day.”
