A sodden baby koala had been found alone near the flooded Brisbane River with experts saying others are sure to have perished in Queensland and NSW.
The floods have also raised fears about longer-term threats to the endangered species, including the loss of food trees and stress, which could hit breeding rates down the track.
It was Saturday when Darcy Modina and her family realised they would have to evacuate their home on 10 acres of riverfront land at Wivenhoe Pocket, just below south east Queensland's largest dam.
They'd been watching the baby and its mother for months, enjoying the process of watching it grow.
But on Saturday, as the waters rose, the mother was no where to be seen and the wet and shivering joey was clearly in trouble. The family knew they couldn't leave it behind.
"As soon as we wrapped the towel around her she was open to being warm and letting us hold her. She wasn't scared at all, just exhausted," Ms Modina said.
The baby was carefully placed inside a green shopping bag and they headed to an evacuation point at the Wivenhoe Pocket Rural Fire Brigade.
But the dramas didn't end there. Flooding meant they were cut off from koala carers but them someone remembered the nearby Somerset Sanctuary, and owner Petrina Paidel took the baby in.
"A truck pulled up and handed me a green bag with a koala in it. She was still soaking wet. I decided to call her Raine for obvious reasons," she said.
"I dried her off and collected some leaf and prepared special milk formula and she ate non-stop for days."
Raine is now in the care of Koala Protection Society vice president Marilyn Splette, who has hand-reared more than 120 baby koalas.
"These floods have left many animals stranded and wildlife carers and vets in desperate need of help," said
Dr Prishani Vengetas coordinates WWF-Australia's wildlife recovery project and says adequate resourcing for carers like Ms Paidel and Ms Splette will be crucial in the months ahead to limit flood impacts on koalas.
"Orphans like Raine will require specialist care if they're going to survive," the veterinarian said, in appealing for people to give to WWF's new wildlife flood appeal.
Beyond that, habitat recovery and tree planting projects will be needed.
Dr Vengetas is particularly concerned about what stress from the floods will mean for koalas already suffering from chlamydia, which affects their kidneys, urinary tracts and hurts their ability to breed.
"When they are stressed by anything it can decrease their immune system even further. The flood is a very stressful event and so the increased stress will lead to higher incidents of disease in them," she says.
"That will in turn decrease their ability to reproduce and we will potentially lose more koala joeys.
"That makes it really important that our wildlife response is coordinated, and that our responders and rescuers and vets are well resourced to provide the care needed to get them warm, healthy and stable, and then back out into the wild."
Last month, the federal government acknowledged koalas had slid further towards extinction by changing their status from vulnerable to endangered.
Land clearing, climate change and disease have sparked concerns the marsupial could be extinct before the middle of the century.
