Why citizen scientists are key in the fight against invasive species

By  Geoff Egan 16 January 2025 6 min read

Creating a biosecurity crisis is shockingly simple.

In the 1850s, Jane Paterson, a settler near Albury planted seeds of a European plant with an attractive purple flower in her garden. She had no way of knowing that plant would spread across southern Australia and become known as Paterson’s Curse (Echium plantagineum), a weed that’s since infested plenty of previously productive grazing pastures.

About 150 years later, an unknown shipping container from the United States arrived in the Port of Brisbane. It had on board a colony of Red Imported Fire Ants (Solenopsis invicta). They had hitchhiked across an ocean before settling in Queensland. In the years since, fire ant nests have been found in an area spanning an estimated 600,000 hectares in southern Queensland, and are at risk of spreading into other states.

Australia receives a huge volume of imports every year, each of which poses a risk of bringing invasive species into Australia. While a complex biosecurity system is in place at the border that blocks most invasive species, early detection of invasive pests, weeds, and fungi in the environment can further protect Australia’s biodiversity and secure important industries.

Sounding the alarm

Luckily, the Atlas of Living Australia’s (ALA) Biosecurity Alerts Service allows anyone with a smartphone to report sightings of invasive species, with the service providing a mechanism to alert management authorities when a species of interest is detected.

This service has already helped detect multiple locally significant biosecurity discoveries, including one of the first discoveries of the Freshwater Gold Clam (Corbicula fluminea) in Queensland.

ALA Biosecurity Lead Dr Erin Roger said recent research also revealed how citizen scientists could deliver biosecurity surveillance through the ALA’s Biosecurity Alerts.

“The ALA Biosecurity Alerts Service connects citizen scientists with biosecurity authorities,” Erin said.

“About 99% of the alerts we have issued have come from citizen scientist sightings. That is thanks to both the volume of records we receive from citizen scientists and the frequency of the data loads that make citizen science such a useful tool for biosecurity surveillance.”

According to Erin, invasive species could impact vulnerable industries like agriculture as well as native species.

"Invasive species – including pests, weeds, and diseases – are a major driver of biodiversity loss and pose significant threats to the national economy and community,” Erin said.

“Some biosecurity threats, like rabbits, and lantana, were intentionally introduced to Australia.

“But more recent incursions – like Red Imported Fire Ants – are accidental introductions that hitched a ride on traded goods. These pests, weeds, and diseases are extremely difficult to eradicate unless detected early.”

To ensure management authorities are notified swiftly of new incursions, we partnered with the ALA and the Australian Department of Agriculture, Fisheries and Forestry (DAFF) through the Catalysing Australia’s Biosecurity initiative to develop the Biosecurity Alerts Service.

Calling in the cavalry

Every week, researchers, government, industry, and citizen scientists submit thousands of sightings of plants, animals, and diseases to the ALA, including invasive species. The ALA aggregates this biodiversity data to make species occurrence information available to governments, landholders, policymakers, researchers, and the public, for open-access use. This includes a wealth of invasive species information, which has been used in Australia’s State of the Environment reports to quantify trends in the abundance of invasive species.

“To make the most out of this invasive species data, the ALA and DAFF devised a system that would provide regular updates, and near real-time alerts, for biosecurity authorities,” Erin said.

“The ALA used the national list of exotic environmental invasive species in the first instance and then a list of plant pests from DAFF to build and test the pest alert system. As the product developed, the ALA improved functionality, adding features like alerts for specific locations; like a national park or a local government area.”

Additional functionality built through CSIRO's investment includes sending an alert for a species only when it is recorded outside of its known distribution (like cane toads) and excluding native species from alerts of invasive species in the same genus. As a result, the Biosecurity Alerts Service now warns subscribed users when a specified invasive species is recorded and loaded into the ALA.

“This allows local, state, or federal management authorities to take early action to minimise possible outbreaks,” Erin said.

(Un)happy as a clam

Until 2023, only two continents were thought to be free from the highly invasive Freshwater Gold Clam (Corbicula fluminea); Antarctica and Australia. But in September 2023, a citizen scientist near Ipswich in Queensland uploaded pictures of an unusual gold-coloured clam to iNaturalist; a citizen science platform that feeds species observations data into the ALA.

This occurrence was subsequently shared with the ALA, which triggered the Biosecurity Alerts Service to notify DAFF of a potential environmental biosecurity threat. The Freshwater Gold Clam can displace native clams and reduce water quality. Following an investigation, Biosecurity Queensland have since confirmed an incursion of Freshwater Gold Clam at Colleges Crossing and other locations on the Brisbane River. The Biosecurity Alert for this occurrence was the first verifiable report of the clam's incursion into Australia. Early detection of this threat has allowed authorities to set up a national surveillance and preparedness strategy to manage the its spread and impact.

A prickly situation

The alerts service has made authorities aware of multiple significant outbreaks of known invasive species, which could have gone undetected without the work of the public.

In October 2023, a member of the public using iNaturalist uploaded an observation of the prohibited cactus Blind Prickly Pear (Opuntia puberula) into the ALA. This observation triggered the alert system to notify the state’s biosecurity authorities.

They inspected the site and found two plants in the area, which the Queensland Herbarium identified as Blind Prickly Pear. One of the plants had a container underneath it suggesting it had been illegally kept as an ornamental plant before being dumped. The plants were removed, and the area was monitored to ensure no further infestations.

One month later, the ALA Biosecurity Alerts Service notified NSW biosecurity authorities that the cactus Rope Pear (Cylindropuntia imbricata) had been found on the boundary of a national park. Rope Pear is listed for eradication on the state’s weed management plan. Local authorities are now working with nearby landowners to mitigate the threat and stop the cactus from spreading into the park.

While the national park is monitored for invasive species, private areas are not. Without the Rope Pear being uploaded to iNaturalist and the ALA alerting authorities, it may have spread before it was discovered.

Far from home

One of the ALA Biosecurity Alerts Service’s most powerful tools is its ability to only send an alert when something is recorded outside of its known distribution in Australia. Authorities can use this alert to triage records for anomalies quickly.

Management authorities are using this service to track the possible spread of invasive species moving down the east coast of Australia, like Cane Toads and fire ants. Following the ALA’s 2024 Myrtle Rust campaign, several reports of Myrtle Rust were recorded well south of where the invasive pathogen (Austropuccinia psidii) was thought to have arrived. This information provides researchers and governments with valuable data to better manage and potentially eradicate invasive species.

Many hands make light work

With many federal and state government-run biosecurity agencies and several local governments now using the service for pest detection, Erin said land managers had a better chance of managing and eradicating invasive species.

“If left unchecked, exotic species can spread rapidly and compete with native flora and fauna.

“By providing a bridge between biodiversity data collectors and biosecurity authorities, the ALA’s Biosecurity Alerts Service is a key part of managing biosecurity threats, which is a huge step in helping protect our beloved Australian species, and vulnerable industries like agriculture.”