Denise Cullen
The clock is ticking for dozens of undescribed species – those lacking formal scientific names – living in and around remote outback springs fed by the Great Artesian Basin (GAB).
Researchers conservatively estimate that there are at least 30 unnamed critters – crustaceans, molluscs, arachnids, and insects – all living a precarious existence in South Australian springs.
Dr Perry Beasley-Hall, an entomologist and evolutionary biologist at The University of Adelaide, says there are around 6,300 GAB-fed springs spread across the country’s arid interior.
This vast aquifer contains enough water to fill the Sydney Harbour 130,000 times.
Around 80% of the springs are in South Australia; the rest are in Queensland and New South Wales.
Beasley-Hall says that these “islands in the desert” support extraordinary numbers of endemic species not found anywhere else.
“The fact that there are thousands of these springs scattered across Australia tells us we probably have a massive amount of undescribed, or unknown, biodiversity,” she says.
But the springs are threatened by industrial activity such as pastoralism, agriculture, and mining – which means many of the creatures which live within them are at risk of extinction before they’ve even been identified or named.
“Until we give something a name, we can’t adequately conserve it,” Beasley-Hall explains.
“The fact that there are thousands of these springs scattered across Australia tells us we probably have a massive amount of undescribed, or unknown, biodiversity.”
Perry Beasley-Hall
Part of the problem is that the taxonomic expertise required to identify these animals is thin on the ground, both within Australia and globally.
“Taxonomic research, the act of discovering and naming species, is fundamental to our understanding of Australian biodiversity,” Beasley-Hall explains.
“Unfortunately, it isn’t viewed in this foundational light by most funding agencies, potentially because the returns of such work aren’t immediately apparent,” Beasley-Hall explains.
The absence of formal names and identification methods means that the fauna cannot effectively protected by environmental legislation such as the Environment Protection and Biodiversity Conservation Act 1999.
According to the Australian Academy of Science, around 70% of Australian and New Zealand species are thought to yet be discovered, formally described, or documented.
“Until we give something a name, we can’t adequately conserve it.”
Perry Beasley-Hall
To date, identification of species has largely relied upon an examination of their morphology (external appearance).
Beasley-Hall and her colleagues at The University of Adelaide are calling for the uptake of new technologies, such as next-generation DNA sequencing, to help identify “cryptic” species – those that are indistinguishable based upon their morphology, but which genetics might tell apart.
This is despite a 2021 report by Deloitte Access Economics, which found that every $1 invested in discovering all remaining Australian species could potentially bring $35 of economic benefits to the nation, in the form of agricultural advances, reduced biosecurity threats, discoveries for human health and biodiversity conservation.
The vast distances between individual springs mean that the species that evolved over millions of years in one location may not be found anywhere else.
“Due to the extent of this isolation, in the event of local extinction particular sites might represent complete species extinction in certain cases,” Beasley-Hall writes in a forthcoming paper to be published in Frontiers in Environmental Science.
Even vertebrates in the springs, which are often better studied compared to invertebrate species, remain at risk. For example, three fish – the Dalhousie goby, hardyhead and gudgeon – are listed as critically endangered.
The Great Artesian Basin and its springs have come under the spotlight recently due to the success of a decades-long nation-wide rehabilitation project designed to ameliorate water wastage through unregulated bore drilling.
The vast distances between individual springs mean that the species that evolved over millions of years in one location may not be found anywhere else.
The capping of more than 700 bores in recent years has resulted in water pressure increasing and natural springs re-emerging.
For example, in Queensland, 19 emerging springs have been identified within a 1,200-hectare area, according to Natalie Pearce, a Senior Project Officer with Desert Channels Group, a community-based natural resource management body.
Pearce says the Desert Channels Emerging Springs project (2020-2022) which was funded by the Queensland Government under the Natural Resources Investment Program, determined that it was important to control weeds at these sites, because they appeared to be acting as pumps to maintain water levels at depth.
“Weed control activities reduced the extent of rubber vine infestations in the area by 72 per cent which allowed greater surface expression of artesian water,” she explains.
“Restriction of livestock access and reduction in feral pig populations reduced the impacts of pugging (the churning up and pushing down of soil) at emerging springs sites.”
The group also undertook monitoring to assess improvements in the condition of emerging springs by measuring changes in macroinvertebrate diversity.
“During the project, there was an increase of 20 species to a total of 79 macroinvertebrate species,” she says.
Further monitoring after the conclusion of the project indicated a further increase to a total of 106 species.
“Of this number, four species were conservation-significant spring endemic species and two are undergoing further study to determine whether they represent previously undescribed species,” she says.
However, Beasley-Hall points out that one-third of bores still flow uncontrolled, while other threats, such as the continuing extraction for pastoral, agricultural and mining practices, demanded attention.
Unsurprisingly, climate change is also likely to impact these “time capsules of biodiversity” through rising temperatures and changing rainfall patterns.
“At present, the volume of stock-accessible water across the GAB is not formally metered and (is) generally estimated based on regional characteristics such as stocking rates,” she writes.
The mining industry is also a significant user of water extracted from the GAB in South Australia, while the extraction of coal seam gas presents a fresh challenge, according to the Great Artesian Basin Coordinating Committee.
The grazing and trampling of wetlands by livestock, along with the presence of invasive (or overabundant native) fauna and flora also threaten the springs and may have already led to local extinctions of fish, spiders and other fauna.
Unsurprisingly, climate change is also likely to impact these “time capsules of biodiversity” through rising temperatures and changing rainfall patterns.
Increasing levels of tourist activity at natural springs also requires careful management to avoid compaction of soil, disturbance of sediment and changes to the water chemistry.
For example, swimming in the Main Pool at Dalhousie Springs in the Witjira National Park is a major drawcard for the area, but a 2003 survey found that visitor activity had eroded the spring banks and negatively impacted resident populations of spike-rush plants.
A spokesman for the South Australian Department for Environment and Water said that entrances to the springs were subsequently modified, with a ladder being removed and stairs installed to ensure people stepped, rather than jumped, into the waters.
Further monitoring had seen no significant damage to the banks since these improvements were made, he says.
Concerns were also raised about how swimmers may affect water chemistry.
“These springs represent an underutilised resource for the development of a roadmap ahead to conserve and characterise groundwater-dependent ecosystems across the country.”
Perry Beasley-Hall
However, hydrogeological work undertaken between 2008 and 2013 indicated that high volumes of groundwater flows into the Main Pool meant the impacts of chemicals from insect repellent and sunscreen from the skin of bathers were negligible, due to the dilution factor.
Beasley-Hall is keen to see a unified mechanism by which GAB spring biodiversity value can be assessed and monitored across the country – and is hopeful that South Australia may lead the way.
For, despite the paucity of data generally, the springs in South Australia are some of the best-studied from biodiversity and taxonomic viewpoints.
“These springs represent an underutilised resource for the development of a roadmap ahead to conserve and characterise groundwater-dependent ecosystems across the country,” she says.