eBay Aiding Invasive Plants? It's Worse Than We Thought

Contemporary gardening has evolved far beyond quiet rural neighborhoods with white picket fences. A global phenomenon, green-thumbed enthusiasts can fuel their hobby by ordering almost any kind of plant over the internet. Unfortunately, new research shows that this could be spreading more invasive species than experts ever expected.

That's at least according to a study recently published in the journal Conservation Biology, which details how an auction platform like eBay can help spread invasive species to parts of the world they may never would have reached otherwise.

And it's not just eBay. Christoph Kueffer of the Institute of Integrative Biology at ETH Zurich led a team of researchers in tracking the internet sales of about two thirds of the world's flora over 10 well-known online trading sites.

Using a program that automatically searches for plant species by their scientific names, they determined which plants were offered from where and how often. And even not knowing the destination of the purchased plants (largely due to privacy policies enforced by the auctioneers) the team was still able to reveal an alarming trend.

"We didn't expect the global trade in plants that are known to be invasive to be so extensive," study author Franziska Humair said in a statement.

Specifically, the researchers identified a whopping 510 plant species that are known to be invasive in at least one region of the world. Of that group 35 were identified as members of the top 100 most invasive plants, according to the International Union for Conservation of Nature (IUCN). (Scroll to read on...)

So what's the most popular invasive plant on global internet markets? According to the study, gardeners are very passionate about passion fruit. Dealers in 17 countries in five very different geographical regions offer the aggressively invasive plant, with sales occurring just about 90 times a day.

The second most frequently offered plant is the cornflower Centaurea cyanus, which is put up for sale more than 80 times a day by dealers in 10 countries.

Overall, from a total of 65 countries, 55 had dealers offering some sort of invasive species for sale. Kueffer was quick to note that a surprising number of those invasive dealers wound up being in Australia. (Scroll to read on...)

"That was unexpected, since the Australians don't allow you to bring any invasive plants across their borders," he explained. "But surprisingly, there are apparently no controls in place to make sure potentially harmful plants don't leave the continent."

Still, the researchers emphasize that the dealers are not to blame. For most of the species offered, they are native to the seller or coming from a region where their introduction has been harmless. And since it's hard to determine if a plant will become invasive until after it already crosses new boarders, regulating plant trade is tricky business.

"To put it briefly, the vast majority of invasive species can be easily obtained with just a click of the mouse," Humair said. Plant trade, as it is now, might just be too quick to keep tabs on.

Additionally, the researchers found one more worrying revalation. While the most popular plant sold on the internet - an African desert rose called Adenium obesum (pictured top) offered more than 3,100 times a day - has so-far never bullied out local fauna in a new region, other African plants are making their global debut through these online auctions.

"South Africa is now showing up on our map," Kueffer warned. "We have no idea whether the plants that are being put on the global market from this corner of world will prove to be invasive species."

"The only way to contain invasions is by limiting the trade in potential invaders," he added. "As online trade blossoms, it makes it even more urgent for the authorities to take action or for responsible large commercial nurseries to adjust their product ranges."

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