How eBay helps non-native species invade new lands

You can buy just about any plant in the world with nothing more than a laptop or smartphone and an internet connection. E-commerce platforms like eBay allow individuals and businesses to buy and sell just about anything, at extremely low cost. All a merchant needs is inventory and the ability to send mail and ship packages. Want some golden bamboo? A live plant can be yours for just $17. Be careful though. If it spreads beyond your yard, it could build up dense stands that crowd out important native species. Moving live plants, even invasive ones like golden bamboo, around the world is easy. Too easy.

Franziska Humair studies consumer behavior as it relates to environmental problems at ETH Zurich in Switzerland, and she’s interested in how to prevent the introduction of invasive species. “Conservationists,” she writes in the journal Conservation Biology, “hope to prevent future invasions by anticipating and preventing the introduction of potentially invasive species through species risk assessments and international trade regulations.” In some places, regulations seem to be working. Biosecurity efforts in Australia and New Zealand, for example, seem to be paying off. But in the EU and the US, introduction rates of new non-native species continue to rise. And the problem with sites like eBay is that it’s too easy to move potentially invasive species around the world through the mail system, bypassing border controls and other regulations.

eBay isn’t the only online e-commerce platform, but it’s one of the largest. And US-based eBay users engage in a variety of international transactions, which is why the researchers chose to focus on eBay’s US market. Humair and her colleagues wrote a piece of software to search eBay listings in the “Flowers, Trees, & Plants” category and looked for 153,394 different plant species. (To be sure that eBay offered a representative sample, the team compared the species offered on eBay to those offered on an additional nine smaller online platforms.)

Over 50 days of searching, they found listings for 2,625 plant species. Forty-one of the most-offered species were classified as invasive, and of 35 plant species on the IUCN’s “100 of the World’s Worst Invasive Alien Species” list, 13 were on sale.

Compared to a list of global flora, invasive species were disproportionately available on eBay. For example, fewer than 5% of the 1,786 species in the Apocynaceae, or dogbane family, were listed for sale – but more than 80% of invasive dogbane species could be purchased.

The researchers acknowledge that the movement of plants around the planet through sites like eBay makes up only a small proportion of the global annual horticulture trade, but they suggest that it’s a particularly uncontrolled market. “About 40% of the studied invasive species were offered on,” they warn, “many on a daily basis, and from numerous countries and different world regions.” A longer search period would likely turn up many more species (some species are seasonal), suggesting that their results perhaps underestimate the true scale of the problem.

Humair notes that most assumptions in biosecurity – that transport of problematic materials can be intercepted at national borders – doesn’t hold up when non-native species can be traded even within national or regional borders. A seller in Florida, for example, can ship an invasive plant originally from Thailand and it can wind up in Montana. Monitoring of selected online platforms would be fairly easy to implement, write the researchers, but attempting to monitor online commerce more broadly is more computationally challenging. And such efforts would need to do more than just monitor species already known to be invasive; they would have account for potential new invasions from parts of the world only recently beginning to participate in e-commerce. They say that monitoring social media could help identify changing tastes in consumer plant purchasing, and that could help researchers and governments with the early detection of new invaders. – Jason G. Goldman | 25 November 2015

Source: Humair, F., Humair, L., Kuhn, F., & Kueffer, C. (2015). E-commerce trade in invasive plants. Conservation Biology 29(6), 1658–1665. DOI: 10.1111/cobi.12579.

Header image: Golden bamboo, via