Parched waterways, dead fish and trees ready to give up: historic big dry grips South Australia

The Guardian

15-04-2025

Usually hardy trees and shrubs are dying, waterways have turned to dust and ecologists fear local freshwater fish extinctions could be coming as historic dry conditions grip parts of South Australia.
Large swathes of the state – including the Adelaide Plains, the Fleurieu, Yorke and Eyre peninsulas and upper south-east – have seen the lowest rainfall on record in the 14 months since February 2024, according to the Bureau of Meteorology.
'The one thing we need more than anything else is rain,' the state premier, Peter Malinauskas, said last week.
Off the back of the state's driest summer since 2018-19, this year weather stations across Adelaide, Mount Barker and Mount Lofty have recorded just 20% of their usual rain.
Adelaide typically gets 64mm from January to March, but this year only 14mm fell. Mount Barker, 33km to the city's south-east, saw only 15mm compared to its average 83mm.
Angus Hines, a senior meteorologist at the BoM, says even though several weather patterns over recent months dragged moisture over the continent from the north-east, 'by the time that airflow reaches South Australia, it's more or less bone dry'.
Adelaide's desalination plant has at times been running at capacity, pumping out 300 million litres of drinking water a day to keep the city's residents off water restrictions.
Outside Adelaide, deep and usually permanent pools and waterways are parched, leaving freshwater fish stranded and dead.
Luke Price, an ecologist for the regional landscape body Landscapes Hills and Fleurieu, says 'we're definitely seeing local extinctions of small populations of fish that usually sought refuge in those pools'.
Together with environment organisation Nature Glenelg Trust, the landscape board has bought tens of thousands of litres of water – along with aerators and filtration systems – to replenish one pool, home to an isolated population of river blackfish.
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Farm dams that acted as refuges for threatened species, like yarra pygmy perch, purple-spotted gudgeon and Murray hardyhead, are also drying out.
'We're looking at having to cart water into those sites just to keep them topped up and keep those fish going,' Price says. 'We really just have to keep persevering until we get a decent break to the season.'
Brenton Grear, the director of Green Adelaide, says water that remained in waterways across metropolitan Adelaide was providing a valuable refuge for freshwater fish and various aquatic invertebrates. But without significant rainfall, some species may need to be rescued.
Wattles and eucalypts, particularly messmate stringybarks, have been dying throughout the Adelaide Hills, while along coastal dunes and clifftops, shrubs like coast daisy bush and coast beard-heath are suffering.
Dr Stefan Caddy-Retalic, an ecologist at the University of Adelaide, says many tree species were showing signs of deterioration and stress such as dead limbs, excessive leaf scorching or sprouting new shoots from the base due to the 'ratcheting' effects of lower rainfall, higher temperatures and development that encroached on tree roots.
As the city's climate continued to shift from warm mediterranean to semi-arid due to global heating, a lot of the introduced trees people associated with Adelaide – like jacarandas, plane trees and oaks – and some natives, such as grey box, will continue to struggle, he says, with potentially devastating consequences for the animals that rely on them for food and habitat.
The ecologist Derek Sandow, of the Northern and Yorke Landscape Board, who manages the Marna Banggara project to rewild southern parts of the peninsula, says even usually hardy native trees looked almost ready to give up.
'You walk through the bush and you see the bigger gum trees are dropping everything, bark, twigs, anything they don't need to keep growing.'
Sandow thinks the endangered brush-tailed bettongs reintroduced to the peninsula are surviving but says like many other macropods – the marsupial family that includes wallabies and kangaroos – they have likely put their reproduction on pause.
'I think it's almost unprecedented what people are seeing here. We are seeing kangaroos grazing in people's lawns. They're looking for anything green they can get.'
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On Kangaroo Island, 110km south-west of the state capital, Dr Jess Marsh, an invertebrate conservation biologist at the University of Adelaide, worries about the island's critically endangered assassin spiders that are only known in one north-west patch where rainfall is also at a record low.
The spiders live along creek lines, and need a moist environment for nesting in elevated clumps of leaf litter. The habitat has already been devastated by bushfire that scorched half the island in 2019 and 2020, she says, as well as the dieback of native plants caused by a root fungus.
'I'm really concerned for that whole population,' Marsh says. 'They need complex vegetation and healthy eucalypts. It's getting hotter and drier, and species like the KI assassin spider are on a knife edge. We are going to lose species.'
In Mount Gambier towards the Victorian border, Bryan Haywood, a senior ecologist at Nature Glenelg Trust, is seeing dramatically low numbers of some butterflies, and hardy banksia shrubs are dying – scenes reminiscent of the millennium drought.
'To see those banksias dead means it's another resource for insects, birds and small mammals that's being lost,' he says.
At one of the trust's properties at Mount Burr Swamp, a 50-hectare wetland which Haywood thought would 'never dry out' can now be walked across 'without getting soggy feet'. Flowering eucalypts were producing scant blossoms, which were dry and without nectar.
Dr Katja Hogendoorn, an expert in native and introduced honeybees at the University of Adelaide, says there were about 150 native bee species across greater Adelaide, and all needed nectar to fly.
'If a bee cannot find nectar, it cannot fly, it cannot produce offspring,' Hogendoorn says. Native bees like the blue-banded bee, which hovered and buzzed around cottage gardens, disappeared after the drought in 2019, and she expects a similar crash to come.
'This issue doesn't only affect bees,' Hogendoorn says. 'It affects all flying insects.'
'When you see a reduction in flying insects, you will see a reduction in birds that rely on flying insects,' she said. 'If we want to save our biodiversity, we have to do something about climate change.'
As the planet warms in the future, the Mediterranean climate of the state's south is expected to become drier. Time spent in drought is projected to nearly double across the Hills and Fleurieu, Eyre Peninsula, Kangaroo Island and northern and Yorke landscape regions by 2030, according to the state government.
Matt Grant is a climate researcher at the University of New South Wales Climate Change Research Centre looking at drought. He says his own research shows parts of South Australia has seen a trend of about one extra month of drought for every five years from 1971 to 2020.
Grant says the observed shifts were not clear enough yet to attribute to climate change, and this was down to the complexity of weather systems. 'There seems to be a turning point around 1950 and, from 1970, you see this trend across a lot of the country,' he says.
Even with possible showers forecast later this week, it could take months or even years for ecosystems to recover, according to Green Adelaide's Grear.
'These conditions highlight the potential future impacts of climate change. Understanding the issues facing species now can help us better identify which aspects of biodiversity are most at risk for the future.'