Insects and other invertebrates thought to go extinct at a rate of one to three species every week in Australia
By ABC environment reporter Peter de Kruijff
10 December 2024
In short:
Invertebrates are creatures without a backbone — like insects, worms, snails, arachnids, freshwater crayfish and mussels — and make up 95 per cent of the animal world.
Scientists say more than 9,000 non-marine invertebrate species have gone extinct in Australia since European arrival in 1788.
What’s next?
Up to 148 species are expected to go extinct in 2024. Researchers want to see more invertebrate habitats recognised by the federal government for conservation.
abc.net.au/news/insects-invertebrates-going-extinct-australia/104560142
Michael Lun, 17, never thought he’d be able to see a creature as stunning as a peacock spider in his Perth backyard.
But the macro photographer was surprised to spot a vibrant male only a few millimetres in size on his fence a few years ago.
“He looked so different to all the other jumping spiders I’d seen before because his abdomen had this beautiful red and blue colouring,” Michael said.
“I’d seen videos of peacock spiders before but I always assumed they lived in rainforests far, far away in some remote area of the world.”
Ever since the encounter, the now Year 12 student has been hooked on documenting the arachnid and helping describe new species.
But he’s worried that many species may disappear before they’re discovered.
New research suggests that Australian invertebrate species — animals without a backbone like arachnids but also insects, snails, crayfish and mussels — are winking out of existence every week.
A study published in Cambridge Prisms: Extinction today estimates about 9,111 species of endemic non-marine invertebrates have gone extinct since European colonisation, although the true figure may be between 1,465 and 56,828.
Whatever the total is, the study’s lead author John Woinarski, from the Biodiversity Council and Charles Darwin University, says it is predicted to keep rising with an estimated one to three extinctions currently occurring every week.
Calculating extinction
The extinction figures in the new study were calculated by comparing the number of native invertebrate species with the average rate of extinction of Australian vertebrates and the global rate of extinction of invertebrates.
Many of these extinctions are assumed to be animals that have never even seen or scientifically described, a phenomenon the study authors called “ghost extinctions”.
Australian National Insect Collection director and systematic entomologist David Yeates, who was not involved in the study, said the new research contained reasonable assumptions for its estimated rates of extinction.
“They certainly shine a light on the plight of many invertebrates in Australia, and add an alarming dimension to the documented extinctions in vertebrates and plants,” he said.
“I do not doubt that we have lost, and are losing, many species every year.”
Entomologist and arachnologist Andrew Mitchell from the Australian Museum, who also was not involved in the study, said the proposed extinction numbers were plausible and perhaps even conservative.
“Many invertebrates have very restricted ranges or have their lives tied to a single other species,” he said.
“For example a particular plant they feed on, which increases their vulnerability to extinction.”
The federal government has set a goal to prevent any new extinctions of Australian wildlife.
When asked about the study’s estimates compared to its pledge, a spokesperson for the Department of Climate Change, Energy, the Environment and Water said “the Australian Government was committed to its target of zero new extinctions.”
“The Australian Government is supporting landscape-scale conservation efforts as well as species-by-species action,” they said.
Why don’t we know much about invertebrates?
Invertebrates make up 95 per cent of the world’s described species.
In Australia there are roughly 320,000 non-marine invertebrates both described and yet to be named.
That compares to 240,000 marine invertebrates and 8000 vertebrates (all the larger animals like mammals, fish, reptiles and birds).
Arachnologist Jess Marsh, from University of Adelaide and a co-author on the new study, said only a third of Australia’s non-marine invertebrates were known to Western science.
“Which means that most invertebrate species are not named and are unrecorded,” she said.
“So that creates huge problems trying to work out what is happening with those species.
“Even for the species that have been named, huge knowledge gaps mean that we don’t know where they are, we often don’t know what’s threatening them, and we don’t know which are at most risk of extinction.”
https://public.flourish.studio/visualisation/20120186/embed?abcnewsembedheight=800&abcnewsembedheightmobile=600
Out of the 67 modern fauna extinctions recognised by the federal government in Australia, only one is for an invertebrate; the Lake Pedder earthworm.
A similar major status check was done for species after the Black Summer bushfires and led to invertebrates like the Kangaroo Island assassin spider, which Dr Marsh studies, being added to the national threatened species list.
The spider, which comes from an ancient lineage spanning millions of years, was only found in a small area in the north-west of the island that was devastated by fire.
“It is likely that some of the species that we don’t have enough data to list have been as badly impacted as the Kangaroo Island assassin spider,” Dr Marsh said.
“The fact that that one was listed as critically endangered indicates that other species that are in the same habitat and have the same restrictions to those areas are likely just as at risk of extinction.”
Dr Mitchell said there were simply too few researchers and not enough funding to cover more than a handful of species when it came to threatened listings.
“The little funding that is available also tends to be awarded to the study of more charismatic species,” he said.
Dr Yeates said criteria used to assign species to rare and threatened status were developed for larger an more well known groups like vertebrates.
“They require a level of certainty about species habits, distribution and abundance that we generally can’t achieve for invertebrate species,” he said.
“In many cases larger, less common organisms that we know well have a much smaller functional impact on our environments than the numerous, diverse invertebrates.”
Invertebrates may be small but provide essential ecosystem services, including pollinating flowers, maintaining soil health and being a food source to larger creatures.
Megan Head, an evolutionary biologist at Australian National University who was not involved in the study, said invertebrates played an important role in maintaining ecosystems and removing them could make those systems more fragile.
“You just never know when you’re going to lose the species that is kind of the linchpin in the system,” she said.
“I sometimes equate it to this analogy where you might remove a screw from an airplane and you might notice no difference.
“But just how many of these screws are you happy removing and still feel feel safe flying in the plane?”
What are the solutions?
The extinction study suggests more investment is needed to increase knowledge of species and to help monitor populations and identify the threats facing them.
It also calls for Australian invertebrates specialists to create a list of species that have not been seen for decades and a greater focus on checking the status of individual species.
Dr Head says the advocacy group Invertebrates Australia, which she is a program manager with, is trying to map out areas containing multiple short-range endemic species.
“These are species that are found only in a very small area and don’t move very far,” she said.
“Often these species kind of co-occur, so you can identify areas that have lots of these species and their potential areas that you could protect, knowing that you’re going to protect lots of species.”
Dr Yeates said modelling invertebrate diversity at a landscape scale could provide a framework for acquisitions into the national reserve system.
“We need to think outside the box using genomics, artificial intelligence and machine learning tools to speed up the way we sample and recognise invertebrate species,” he said.
“This inevitably means applying more resources to the challenge.”
The battle to save Maratus yanchep, a rare peacock spider, illustrates the challenges of arachnid conservation.
The spider, which was described in 2022, has only been found so far in a three hectare patch of coastal dunes in Yanchep, a coastal suburb north of Perth.
Most of these dunes is set to be replaced by a seaside housing estate.
Now the race is on to find if the species lives outside the development area or if it can be put onto a threatened species list.
Invertebrates Australia is working on a threatened species bid for the spider but there are concerns it will come too late.
Alex Barlow, an invertebrate zoologist from Perth, said even without a listing the developers could get volunteers or a professional team to relocate some of the spiders.
“There’s millions [of dollars] in these projects; there’s no reason for it not to happen,” he said.
“Also they could just as easy relocate 10 to 20 plants [with the spiders] from the area to a forever bushland so that they’re preserved.”Artistic arachnids a photographer’s dream
Photo shows Photo of spider next to painting.
Akin to the famous Van Gogh painting, the starry night peacock spider highlights the rare species’ beauty. But some people are concerned not enough is being done to protect the arachnids.
The developer, Peet, did not say whether it would survey or undertake any relocations of the species.
The project was approved before state environmental guidelines on short-range species surveys was published.
A spokesperson for the company said it was meeting all required government and regulatory approvals.
Michael Lun hopes something can be done for the peacock spiders but also has restless nights over other potential ghost extinctions.
“The question keeps me up at night a lot,” he said.
“How many species have we already lost to stuff like this [development] that I will never ever get to see in my lifetime?
“And how many more species are going to get lost that we’ll never even get to see that still are around to this day?”