As 2022 has unfolded, repeated flood events have proved devastating for scores of communities in the eastern states — destroying lives and livelihoods.
But for nature, floods are a good thing, a critical life-giving force. Right?
It's a comforting silver lining in the face of a devastating natural disaster.
But like floodwaters themselves, the reality is far more murky.
Warning: this story contains information some readers may find distressing.
Scientists say back-to-back extreme events are complicating and compounding the environmental outcomes of floods.
So while many species are surviving and thriving because of the floods, others are now struggling due to starvation and displacement.
While some turtle species do well in floods, ecologists are worried about endangered endemic species such as the Mary River turtle, which is likely to have lost many nests of eggs during the breeding season. Supplied: Marilyn Connell
Silt washed out of inland rivers has settled onto vast seagrass beds along Queensland's Fraser Coast, killing off the main food source for dugongs. Supplied: Great Barrier Reef Marine Park Authority
Marine ecologists say there's been an increase in green sea turtles with soft shell disease and they're investigating if it's related to flood events. ABC Capricornia: Erin Semmler
When blackwater events sucked the oxygen from the water in some parts of flooded rivers, freshwater crayfish were seen crawling up trees and out of the water to breathe. Supplied: Nick Whiterod
Straw-necked ibises are among the waterbirds that boom during floods. Ecologists say the birds love to eat locusts and so the environmental benefits spread beyond river systems. Supplied: Heather McGuinness, CSIRO
Scientists think platypuses can escape the force of floods by sheltering along the edges of rivers. But their nests can be ruined when floods happen during the breeding season. Supplied
Wildlife carers say floods can inundate burrows and displace wombats. Carers have received call-outs to help native animals such as wombats during the floods. ABC Open
Wildlife rescue volunteers say eastern grey kangaroos can swim if caught in floodwaters, but some drown. After the floods, the boom in plant growth could benefit the roo population, ecologists say. Unsplash: John Torcasio
Possums rely on big, old trees for places to make their nests. Many species of important habitat trees get the water they need to survive during floods. Supplied: Brisbane City Council
Red gums, coolibah and blackbox are all eucalyptus trees that rely on floods for a periodic influx of water. Supplied: Richard Kingsford
Flourishing in the floods
When rivers flood, the torrent of nutrients sets off a boom in the food chain, from algae and plants to insects and other invertebrates, frogs, fish, turtles and birds.
Waterbirds in particular flourish in floods.They flock, they feast and they breed.
River ecologist Richard Kingsford says it's a welcome boost to their declining numbers.
"It's in times like this that we get these phenomenal colonies of waterbirds, which are the flagship for what's happening," Professor Kingsford says.
"It's that vast expanse, that smorgasbord of food that's out there which really caters for every different species.
"It's incredible, particularly in the Murray Darling at the moment, because all of the rivers pretty much are in flood."
Trees like river red gums get the drink they need and underground aquifers are recharged in preparation for dry times.
"[It] keeps the health of the whole river system going for probably years, maybe even decades afterwards," Professor Kingsford says.
Dugong population devastated
For dugongs inhabiting the waters off some parts of Queensland's south-east coast, it's a devastatingly different story.
These huge marine mammals have been washing up sick or dead along the Fraser Coast because silt washed downstream through the flooded inland river system and out to sea has killed most of the seagrass they rely on for food.
"We've seen a massive increase in the number of strandings," says animal ecologist Kathy Townsend.
"We've seen 10 times the numbers than we were seeing in say, 2019, so basically starvation is an issue."
It isn't just dugongs that need the seagrass, but a whole array of species.
Scientists are also investigating whether the number of green sea turtles washing up unwell with soft shell disease is also linked to flooding.
"Australia is a land of booms and busts, that's how Australia has been for centuries," Associate Professor Townsend says.
"But when you pressure it to the point where it goes over the other side of that tipping point … that's what we're seeing for seagrasses in these flood events."
Good floods and bad floods
Burra McHughes is a Ngemba and Muruwarri man from Brewarrina in north-west New South Wales, an area that has been inundated by floodwaters.
He says this year's floods have been too big.
"You need the right floods … that the environment needs, the plants, the animals, us as people, you know, to survive again."
Mr McHughes works with fire services and is passionate about bringing First Nations wisdom back to land management.
He says the cycle of life needs to follow a pattern of good fire, good rain and good flood.
"We can't have the bad floods like we have now," he says.
"Just like good fire and bad fire, there's a big difference."
Many ecologists agree.
Senior researcher with CSIRO Simon Linke says floods are critical for the life cycle of many native fish species.
They sweep material from land into water and turn it into fish food, allowing fish to move between habitats, to shelter from predators, and breed and mature.
But, he says, these benefits are at their best in moderate floods.
"These large floods can bring too much energy into a river," Dr Linke says.
"It's a bit like having a veggie patch. Some water and some fertiliser is awesome. Too much water and too much fertiliser can kill things."
And that is exactly what has happened in some parts of the Murray Darling river systems during this year's floods.
So much organic matter has been washed into the water, the decomposition process has sucked up all the oxygen.
This has created "blackwater", which has killed large numbers of native fish, including iconic species such as the Murray cod.
Too much, too often
Ecologists say blackwater events can be within the realm of normal natural processes.
But they start to worry when it happens off the back of similar fish kills during the recent drought.
Integrative ecologist Dana Bergstrom is leading a study on multiple extreme events from Australia to Antarctica.
"We expect blackwater events in floods, but if you keep having drought, flood, drought, flood, then ultimately your ecosystems get degraded if there's not enough time in between those events to repair," Professor Bergstrom says.
"Floods are rejuvenating, but they can have a sting in the tail."
Professor Bergstrom says the environmental effects of floods can't be looked at in isolation; they must be examined in the context of back-to-back extremes such as fire, drought and heat waves.
"The climate scientists call them compound events, which means one event after another," she says.
"If you keep having rapid or multiple events, it's basically chipping away at the backbones of your ecosystem."
Professor Bergstrom says this leads to weaknesses in the system and, ultimately, tipping points.
"And you may not notice them … people may not see the process of collapse because there's just a little bit here and a little bit there and then all of a sudden, bang, how did that happen."
Above the waterline
Many of the native animals that work hard to survive big floods are land dwelling.
Everything from kangaroos and wombats to lizards, bandicoots and dunnarts will flee, seeking higher ground, with varying degrees of success.
Wildlife rescue groups have fielded big increases in call-outs for animals in distress.
Tania Begg, an ecologist who runs a wildlife shelter near Rushworth, in north-central Victoria, says many wild animals have not survived this year's flood events.
She says animals such as kangaroos can hit strife when they are washed up against fences or are stranded on islands where they suffer from exposure and a lack of food.
"A lot of the youngsters will have drowned, particularly in mums that have been swimming in water … they have drowned in pouches."
Ms Begg says animals are also displaced. Habitats, burrows and shelters are inundated and destroyed, leaving animals competing for resources, out of their normal environment, and vulnerable.
"They're ending up in weird places and they're also being hit by vehicles on roads," she says
Ms Begg says those that endure will often be stressed and prone to parasites and disease.
"Once the water starts to recede, any that have survived are going to be highly stressed."
High and dry
While some kangaroos and wombats will die in floods, the waters will also result in great surges of plant growth that may help fuel their populations when the disaster is over.
Wildlife ecologist Euan Ritchie says it's very difficult to balance the loss of individual animals with how the overall populations will cope in the longer term.
"Some animals will be winners and some animals will be losers," Professor Ritchie says.
"As sad as it is losing some kangaroos, it's probably not going to have a big effect on their population."
But, he says, no-one can be entirely sure because too little is known about how large-scale flooding affects Australia's wildlife.
"We should be looking at what may or may not have happened to plants and animals and other species as a result of these floods," Professor Ritchie says.
"We went looking for information on how species might be affected by flooding and there's very little."
Fires and floods
After the unprecedented Black Summer fires of 2019-2020, it was estimated that more than 3 billion native animals had died.
Ecologists expressed concern for the future of vulnerable plant and animal species.
"There seems to be far less coverage of the impact on animals as a result of floods than there was with fires," Professor Ritchie says.
While both fire and flood are critical for growth and regeneration, he believes that too much of either has the potential to tip the balance.
"Floods happen, fires happen. They've been happening since day dot.
"So they are normal, but when you have these frequent events stacked on top of each other, that is not normal. And that's what we're seeing more and more of."
This frequency, Professor Ritchie says, has been predicted by climate scientists for decades.
"As troubling as this is, it's not too late. We have the ability to turn things around," he says.
"And we have an obligation to protect and sustain communities and the environment.
"A major way of achieving that will be people putting pressure on governments to reduce greenhouse gas emissions."
Turtling forwards
While scientists strive to catch up with how climate change is impacting on the way floods affect the natural environment, animals that we still know little about are quietly doing their thing.
Conservation biologist Deborah Bower says turtle species come in to clean up the mess during floods.
"They are the garbage collectors," Associate Professor Bower says.
"When you have a system with lots of dead carrion, turtles can come along and clean that up."
But in huge flooding events turtles can also get knocked around.
It's currently turtle breeding season, and nests can be inundated and washed away.
But Associate Professor Bower's hope is that overall, they are making the best of things.
"I think that there are overwhelming benefits to turtles when floods happen because they can respond to really productive environments."
