Humans are polluting Antarctica with alien seeds

New Scientist : In a study published online yesterday in Proceedings of the National Academy of Sciences, Steven Chown of Stellenbosch University in South Africa and colleagues discuss the potential risks for Antarctica’s plant biodiversity as more people visit the continent. During the International Polar Year’s first season, 2007–08, the researchers examined the clothing and bags of some 33 000 tourists and 7100 scientists who passed through. They found that, on average, each person imported about 10 plant seeds. And because many of the people had visited other cold places, many of the species of seeds they accumulated could easily survive Antarctica’s cold climate. “Invasive alien species are among the primary causes of biodiversity change globally,” writes Chown and colleagues. The group’s report highlights which parts of Antarctica are most at risk and suggests ways to mitigate the threat both now and as the continent’s climate changes due to global warming.