World’s rarest macadamia close to extinction after Australian bushfires

A group of dedicated enthusiasts recently braved the fire ravaged landscape in central Queensland’s remote Bulburin rainforest to establish how Macadamia jansenii, a species as rare as the country’s Wollemi Pine, had fared during the blaze which left vast tracks of Australia in ashes following the worst bushfire season in living memory according to reports.

Field naturalist and retired sugarcane farmer, Keith Sarnadsky, a member of the inspection team to visit the park for the first time following a massive clean up operation which involved clearing fallen trees on the roads, said it appeared a low intensity fire was enough to kill the rare Macadamia jansenii. “Almost all of the small M. jansenii trees touched by the fire appeared to be dead. Some of the larger plants may have died due to their own stumps burning, although some suckers have appeared on some of the stumps, also, most of the dead plants didn’t appear to have an extremely hot fire burning around them,” Sarnadsky said.

The discovery of about 150 trees in 2018 had trebled Australia’s known population of M. jansenii, or the “Mj”, a species first recognised by the modern scientific community in 1992. Macadamia nut trees are indigenous to Australia have been harvested by  Aboriginal Australians for thousands of years. 

The rare M. jansenii are restricted to this one small catchment in the Bulburin National Park and was believed to hold the key to climate change resilience research in macadamia trees as they were able to survive hotter and drier conditions.

Sarnadsky who found the new trees over several expeditions in the spring of 2018, was also on the 1983 expedition when cane farmer Ray Jansen initially discovered the Macadamia jansenii species, the first new macadamia in 120 years.

Macadamia Conservation Trust executive officer, Denise Bond, said the existence of the new trees was unknown until the Foundation for Australia’s Most Endangered Species provided funding to allow Sarnadsky the opportunity to widen the search for the newly discovered sub-species.

 “We were thrilled when Keith discovered these new trees to add to the tiny original population of 60 individuals, but that same year wildfire came within 10km of the habitat, and now our fears have been realised with the December 2019 fires burning at least a third of the new trees,” Bond said.

“We hoped they were safe, nestled in sub-tropical rainforest, but we have been proved wrong. Luckily, we have a small but dedicated team of traditional owners, the Gidarjil Rangers, amateur and professional botanists, researchers and park rangers who are passionate about protecting this endangered macadamia and the subtropical rainforest where they grow. We’re applying for funding to increase fire and weed management across the Bulburin landscape,” she said.

A conservation trust founding member, Ian McConachie said as the M. jansenii grew in an area much hotter than where commercial macadamias were produce, it was possible its genes could be used in the future to mitigate the effects of global warming on macadamia crops.

Leaf samples taken from the newly discovered M. jansenii are currently under analysis to establish how the genetic diversity of the population is distributed across its habitat. The 43 original trees have meanwhile been cloned, with new trees planted in botanic gardens across Australia as part of an “insurance population”.

The trust aims to learn more about the ecology and genetics of M. jansenii and preserve its genetic diversity in ex-situ plantings as well as increasing the range of its current habitat, particularly in anticipation of the impacts of climate change, Bond said

The Australian non-profit is the world’s only charity devoted to conserving macadamias and in a previous article published in The Macadamia, the trust made an appeal to South Africa’s macadamia farmers to support their work in protecting the world’s original wild macadamia trees.

Denise Bond can be contacted on her email at denise.bond@macadamias.org or visit wwwmacadamias.org.au.