Weeds are plants that grow where they are not wanted and cause harm to the environment, agriculture, or human health.
Some weeds are introduced to new places through the trade of ornamental plants, the kind grown in homes and gardens, while some can escape cultivation and become invasive, spreading rapidly and displacing native species.
Australia has a list of prohibited weeds that are banned from importation, sale, and movement within the country.
These weeds are considered to pose a serious threat to Australia's biodiversity, economy, and society.
However, despite the strict regulations, some people still trade these weeds online, either knowingly or unknowingly.
How Researchers Uncovered the Online Trade of Illegal Weeds in Australia
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The study was conducted by a team of researchers from the University of Adelaide, led by Jacob Maher. They used specialized software called 'web scrapers' to monitor trade on a public online marketplace in Australia.
Web scrapers are programs that automate the collection of online data, such as advertisements, prices, images, and descriptions.
The researchers collected data from over 300,000 advertisements for plants posted on the marketplace over a 12-month period, and then compared the advertised plants with the list of prohibited weeds in Australia and identified hundreds of matches.
They also analyzed the characteristics and uses of the advertised weeds, as well as their geographic distribution across the country.
The results showed that 517 advertisements for 285 different weed species were found on the marketplace.
These included cacti, succulents, pond plants, grasses, shrubs, trees, and vines. Some of the most frequently advertised weeds were prickly pear cactus (Opuntia spp.), water hyacinth (Eichhornia crassipes), salvinia (Salvinia spp.), and fountain grass (Pennisetum setaceum).
Theresearchers found that some of the advertised weeds were associated with specific uses by traders, such as food, medicine, craft, or decoration.
For example, some cacti were sold as edible fruits or medicinal plants.
Some pond plants were sold as water filters or fish habitats. Some grasses were sold as lawn alternatives or ornamental plants.
The researchers also found that the illegal trade of weeds was widespread across Australia. The advertisements were posted from all states and territories, except for Tasmania.
The highest number of advertisements was from New South Wales (157), followed by Queensland (132) and Victoria (97). The lowest number was from Northern Territory (4).
According to Maher, these weeds have the potential to invade natural areas, reduce agricultural productivity, increase fire risk, degrade water quality, and threaten native biodiversity.
He added that some of these weeds are also known to be toxic or allergenic to humans and animals.
The researchers suggested that governments adopt web scraping technology to assist in regulating the online trade of plants.
They also recommended increasing public awareness and seeking cooperation from online marketplaces as solutions to this growing problem.
Maher said that currently, these online marketplaces allow people to advertise and purchase invasive species, whether they are aware of it or not.
He said that regulation is needed, but we also need to cultivate awareness among plant growers of this issue and we need help from marketplaces to regulate trade on their end.
The technology developed in this study is now being used by biosecurity agencies in Australia to monitor and regulate the illegal trade of plants and animals online.
