What are visitors bringing to Antarctica on their shoes?

When tourists and scientists visit Antarctica, they bring along all kinds of field gear. But hidden in their shoes, jackets, and bags is more insidious cargo: plant seeds that could lead to damaging biological invasions.

Antarctica may seem remote, but more and more people are visiting the continent for vacations or research. The study authors used vacuum cleaners to take samples from 853 visitors in 2007 and 2008 who arrived by ship or plane. These travellers included scientists, tourists, national program staff, and crew members.

The team then analyzed seeds and other plant fragments collected from the visitors and tried to identify the species. The researchers also gave questionnaires to 5,869 people who had visited Antarctica in 2007-08, collecting information on which locations they had visited before arriving and how they had used their gear.

Fifty-eight percent of national program staff members who had been to parks, reserves, or botanical gardens before their Antarctica trip were carrying seeds, compared to only 23 percent of those who hadn’t visited such locations. Similarly, visiting a farm or rural area increased the likelihood that a tourist was carrying moss or lichen.

Overall, the sampled visitors were toting 2,686 seeds and 535 bryophyte and lichen fragments. One visitor carried a whopping 472 seeds from 86 species. During the 2007-08 season, the team estimates, people probably brought a total of about 74,000 seeds and 17,000 bryophyte and lichen fragments to Antarctica.

Seeds were the most likely to be found on shoes, bags, and pants, the researchers report. Ideally, they say, people should use new clothes and gear every time they visit Antarctica. But a less costly solution might be to provide visitors with these items only once they’re on their way to the continent or have already arrived. Washing and vacuuming is “less effective, but still more efficacious than no treatment at all,” the team writes. Roberta Kwok | 10 March 2014

Source: Huiskes, A.H.L. et al. 2014. Aliens in Antarctica: Assessing transfer of plant propagules by human visitors to reduce invasion risk. Biological Conservation doi: 10.1016/j.biocon.2014.01.038.

Image © Alexey Laputin | Shutterstock