Alien invasions are being made easier through a click of a button. Researchers at the Federal Institute of Technology in Zurich monitored plants sold on eBay over 50 days and found 40% of species sold online globally were listed on an invasive species list. To be listed, plants have to be deemed invasive in at least one country.The researchers said "horticultural e-commerce of invasive species was not effectively regulated".Invasive plants are not indigenous and are thus without natural enemies, which can result in their growing out of control, displacing animals, using too much water or posing fire risks.For example, invasive plants in Cape Town are more likely to burn in a veld fire than Fynbos.The Swiss researchers found a total of 421 plants species from South Africa were on sale on eBay, but only 4% sold were listed on the invasive species list.One researcher, Professor Christoph Kueffer, said: "South Africa is now showing up on our map. We have no idea whether the plants that are being put on the global market from this corner of the world will prove invasive."The only way to contain invasions is by limiting the trade in potential invaders.""Online plants sales are a huge drama globally," said Kay Montgomery, Head of SA's Biosecurity Advocacy Programme. "South Africa is very concerned about it."A few years ago people doing research with Montgomery contacted 50 international plant traders and at least 20% were willing to sell plants [seeds] listed as invasive to South Africa.She said the Department of Environmental Affairs had set up a bio-security department which was installing huge X-ray machines at OR Tambo International Airport from next year. These will be used to scan incoming post and luggage for plant material from next year.Wits professor from the School of Animal, Plant and Environmental Sciences, Marcus Byrne, urged South Africans to buy plants at nurseries rather than online."It can take 100 years for a plant brought to a country to become invasive. We can't take that risk."..