An incredibly rare eucalyptus tree found in some of Sydney’s most densely developed areas has been confirmed as a new species.
- Scientists use genomic sequencing to confirm eucalyptus is a separate species
- There are only 700 individual trees left in the Hills district of north-west Sydney
- Seedlings to be planted in a secret place
The species which has yet to be officially named is a type of shrubby eucalyptus with cup-shaped fruits and is found in the Hills district, northwest of Sydney.
“It’s an unassuming eucalypt,” said Australian Institute of Botanical Science scientist Trevor Wilson.
“It’s not too tall, it’s actually a mallee, which means it doesn’t have a main trunk system, it looks very shrubby.”
It was first spotted in the suburbs in the 1990s, but only now can scientists say with certainty that it is a distinctive new species.
“It’s been a long time coming,” Dr. Wilson said.
To answer this question, the Australian Institute of Botanical Sciences used genomic sequencing to identify key differences from other types of eucalyptus and better understand its evolutionary history.
Dr Wilson said the results showed that not only was it not a hybrid of two other species, but that it was further apart than expected.
“That means we’ve identified quite a distinct and more unexpected amount of biodiversity right on Sydneysiders’ doorstep.”
Seedlings to plant in secret places
It is estimated that only 14 populations consisting of 700 individual specimens remain in Sydney.
“He has never been seen anywhere else outside of Sydney,” Dr Wilson said.
“Being close to a lot of urban development and land clearing puts something like this in extreme danger.”
The species, currently known as Eucalyptus sp. Cattai, was first classified as endangered in 1999 before being classified as critically endangered in 2005.
Now it will have its own official name and description, which scientists hope will boost conservation efforts.
At the Mount Annan Australian Botanic Garden, seedlings are grown to be planted in secret locations.
But many of the seedlings grown from seeds collected from the “Cattai” species turned out to be hybrids.
Given the low number of specimens in the wild, Dr Wilson says it’s no wonder many trees have become “frozen” with other species to survive.
Hybridization is rare in the animal world, but it is quite common between close plant species.
“Eucalyptus trees are known to be crowded and easily receive pollen from other eucalyptus species.
Although it is a natural phenomenon, scientists want to increase the number of original species.
They are now using genomic sequencing to identify genetically “pure” seedlings to transfer to suitable nearby habitat.
“It’s a way to improve the resilience of some of these populations to maximize their survival in the wild,” Dr Wilson said.
The institute partnered with Jiangsu University in China and the NSW government’s Saving our Species program to undertake the project.
Dr Samantha Yap, from the Institute’s Center for Ecosystem Resilience Research, said confirmation that it was a separate species was important.
She said genetic studies are increasingly being used to overcome some of the barriers to species discovery.
“For effective conservation, the first step should be to assess what is a rare species and what is not, and a genetic study presents a very effective approach,” she said.