photographer CHRIS FERNANCE
What if trees could walk? In a changing climate, some forms of life are moving poleward to cooler, wetter conditions. Yet our native plants are firmly rooted in place.
In winter 2022, the critically endangered Morrisby’s gum (Eucalyptus morrisbyi) is getting a helping hand to shift its range. Unique to Tasmania, there are only 43 mature trees of this species left in the wild, split across two locations on Hobart’s eastern shore. It is a talismanic species for the people of Cremorne and the Clarence area.
It is also well-known among the University of Tasmania’s plant science graduates as researchers and teachers have focused on this species for decades. Yet it is too late for Morrisby’s gum to save itself through setting seed and natural migration.
Several organisations, led by NRM South and Enviro-dynamics, are collaborating to bring the species back from the brink of extinction. Dr Magali Wright from Enviro-dynamics, described Morrisby’s ideal habitat.
“The places they’re surviving – and where older plantings are doing well – is where there is a lot of soil moisture, such as in a gully or at the base of a dam wall.”
Through winter and spring this year 4,164 Morrisby’s gum seedlings will be planted – both within the species’ current range and in new, future climate proof sites.
I visited one of the conservation plantings along the Risdon Vale Creek. Tasflora contractors Duncan Marshall and Jamie McLeod were planting seedlings grown by the Royal Tasmanian Botanical Garden’s nursery for Clarence City Council. The six-month-old seedlings were carefully planted and protected with a tree guard to prevent possums or pademelons from nibbling the palatable leaves.
As site manager Duncan Marshall watered in a seedling, he explained, “The plantings are done in winter so the trees can get established and send their roots out for water before summer, the driest time of year.”
Getting more seedlings into the ground raises community awareness as people walk and cycle past this species. It also creates stepping stones for future animal pollination among remnant stands.
The other tactic is to plant seedlings in areas that will be wet enough in a future climate. Dr Peter Harrison, from the University of Tasmania, has developed a model to identify the species’ future climate range.
“The climate modelling done by the university allowed us to choose four sites on private agricultural land between Orford and up towards Swansea,” said Magali Wright.
Yet planning for future climate conditions while experiencing current ones involves trial and error. “Some previous plantings were killed due to frost so we removed inland sites from the model as they might be too cold to get plants established under current climate conditions,” Wright said.
Climate change and drier conditions are just one challenge facing Morrisby’s gum. It must also combat munching from native mammals, insect attack and a limited amount of seed produced by wild trees.
This barrage of challenges has made Morrisby’s gum one of Australia’s most threatened eucalypts. It will take many helping hands to overcome these threats.
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In 2018, a conservation action plan was developed by a partnership of local government agencies, researchers and conservation groups. The 20-year plan aims to bring Morrisby’s gum back from the brink of extinction. NRM South and Enviro-dynamics have received funding from the federal government to carry out the plan’s top priorities.
Their many-pronged defences include protecting existing adult and juvenile plants from browsing mammals and insects. They are also enlisting the help of landowners to plant Morrisby’s gums on their properties, to improve connectivity between wild remnant populations.
“Around Cremorne, there are some beautiful specimens,” Magali Wright said. “When plants are grown on private property, they are well cared for and watered, so they grow really well and produce seed.”
Urban areas also have a higher number of pets, such as dogs, which deter possums from creeping into the backyard and nibbling seedlings.
Previous recovery efforts established seed orchards about 25 years ago. These “orchards” of Morrisby’s gum are genetically diverse as they were grown from material collected before the species declined in number. These orchards supply seed in quantities which the wild trees cannot produce, which allows for larger, more genetically diverse conservation plantings.
In addition to growing new plants, seed for this gum is also banked for safe keeping, with 165,000 Morrisby’s gum seeds banked at the Tasmanian Seed Conservation Centre.
Dr Rebecca Jones and her students from the University of Tasmania have studied the genetic makeup of the Morrisby’s gum seed store. Their findings ensure the seeds used to grow plants for the conservation plantings and future proof sites represent as much genetic diversity as possible to maximise the species’ ability to cope with future climate change.
Back at Risdon Vale Creek, the final seedling has gone into the ground. Only time will tell if Morrisby’s gum is part of our future landscape. The ongoing hard work of local partnerships has given the recovery of this species a strong head start.
Chris Fernance is a photographer and writer based in Blackmans Bay, Tasmania. She has a background in marine science and science communication. She moved to Tasmania in 2021 which allowed her to be closer to the ocean and pursue her passions for scuba diving, photography and storytelling. More of her photography can be seen at www.chrisfernance.com.
