A new national recovery plan has been adopted to help save the world’s only wild macadamia plants from extinction.
- Macadamias are a native Australian plant
- They are endangered in the wild
- The future of the global macadamia crop could rely on wild plants
The origin of the global $1.58 billion macadamia nut industry, Australia’s wild population has been decimated by clearing, with three species listed as vulnerable and a fourth critically endangered.
The Macadamia Conservation Trust estimates as few as 8,800 wild trees remain in small pockets of remnant sub-tropical rainforest in a thin strip along the east coast from Gladstone in central Queensland to northern New South Wales.
Trust founder Ian McConachie said he doubted many Australians understood the native plant’s precarious position in the wild.
“At least 80 per cent of the wild macadamias that existed when European settlement started have been lost, and we’re continuing to lose wild trees, and we’re losing their specific genetics,” Mr McConachie said.
“The easiest way to think about it is that macadamias love to live where people live, so they like rich red soils, ideally within 50 kilometres of the sea, with a view, if you like,” Macadamia Conservation Trust executive officer Denise Bond said.
“That’s the area between Northern Rivers and Brisbane and the Sunshine Coast that has been very heavily cleared for people to live and grow crops.
“The result is that less than 20 per cent of macadamia habitat remains.”
In 2019, Queensland researchers were shocked to discover the global macadamia industry may have originated from nuts from a single tree or a small number of trees taken from Queensland to Hawaii in the 19th century.
Given the lack of genetic diversity in the farmed crop, the race is on to preserve wild macadamia trees to improve traits like disease resistance, size and climate adaptability.
“We feel that we’ve still got a big job to do in just letting Australians know that macadamias come from here, and we’re their guardians. If we don’t protect them, no one will,” Ms Bond said.
“Every country that owns the ‘crop wild’ relatives of an important plant species has an obligation to the rest of the world to preserve that genetic diversity.
“Otherwise, a disease could go through and wipe out an important food crop.”
Recovery plans outline the research and management actions necessary to stop the decline of a species and guide plan ways to coordinate and implement programs that are expected to improve the plight of the threatened species.
Ms Bond said getting federal approval on the new national recovery plan for macadamia species had been a “long, drawn-out process.”
She said the first plan, adopted in 2012, was well overdue for an update.
“Every five years, they get reviewed. We reviewed the plan, and then it just got stuck in politics, and we’ve been anxiously lobbying to get the new plan approved because it really does guide our actions for conserving wild macadamias,” Ms Bond said.
“Wild macadamias are threatened by clearing, habitat fragmentation, weeds and fire, and vulnerable to extinction if their remaining habitat is not carefully managed.”
Four threatened species
Queensland’s Nature Conservation Act lists Macadamia jansenii as critically endangered, while Macadamia integrifolia, Macadamia ternifolia, and Macadamia tetraphylla are recognised as vulnerable.
Jansenii was only recognised by the modern scientific community in 1992 after being identified 150 kilometres north of the closest macadamia population.
Ms Bond said it was one of Australia’s most endangered species, with less than 120 known trees remaining in a 6,000 square metre area of natural habitat in the Bulburin National Park, south-west of Miriam Vale.
“It’s as rare as the Wollemi pine,” Mr McConachie said.
“In December 2019, a major bushfire came through that area, and about 30 per cent of the wild trees were burned. Some have recovered, some have not recovered.”
Mr McConachie, who was instrumental in developing Queensland’s commercial industry, said macadamias were probably the only new food source in the world that has been domesticated in the last 1,000 years.
“Macadamias are Australia’s gift to the world, they’re the finest nut in the world and we’re in a position to be able to do something to conserve them for all time,” Mr McConachie said.
Horticulture Innovation Australia has a strategic investment plan to assist with a breeding program for the conservation of wild Macadamia and support the work of the Macadamia Conservation Trust.
The recovery plan notes that populations of wild macadamias on private land in Queensland are generally located where protective fencing and weed control would have little or no negative economic impact on the viability of farm enterprises.
It found a lack of protection of wild Macadamia populations may have significant economic impacts on the long-term viability of the Macadamia nut industry globally through a reduction in genetic diversity.
“It’s really important that we protect what remains and make sure that macadamias can keep evolving into the future,” Ms Bond said.
Key stories of the day for Australian primary producers, delivered each weekday afternoon.