Antarctica Visitors Unwittingly Bring Invasive Species The far reaches of Antarctica are no longer visited only by scientists and their support staff. Adventure tourists and curiosity seekers from Europe, North America and beyond now come by the boatful — and they're bringing some souvenirs from home. Ecologist Steven Chown tells Robert Siegel that visitors unknowingly carry seeds on their clothes and bags. He says they've helped spread dozens of invasive plant species on the continent and risk permanently changing Antarctica's ecology.
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Antarctica Visitors Unwittingly Bring Invasive Species

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Antarctica Visitors Unwittingly Bring Invasive Species

Antarctica Visitors Unwittingly Bring Invasive Species

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Antarctica is remote and vast, much of it covered with ice and thought to be largely inhospitable to non-native species. An international treaty signed back in 1959 was intended to maintain that inhospitality. Antarctica was set aside as a scientific preserve. But the number of visitors has gradually increased over the years. And it's getting harder to keep plant seeds from hitching a ride on the boots of scientists and tourists alike.

Ecologist Steven Chown has been studying this problem and his findings were published in the proceedings of the National Academy of Sciences. He is professor at the University of Stellenbosch and he joins us now from his home in Somerset West, South Africa.

Welcome to the program.

PROFESSOR STEVEN CHOWN: Thanks very much, an honor to good to be talking to you.

SIEGEL: And you've written that 70,000 seeds were tracked into Antarctica in one recent year. How do they get there and how did you come up with that number?

CHOWN: They arrived on the clothing, boots, and in the day packs and camera bags of scientists, tourists and support personnel. We simply had a look at what was in their gear and these visitors have plenty of seeds coming in on them.

SIEGEL: Now, it would seem to a layman that if you tried purposely to plant seeds in Antarctica, good luck - the area doesn't seem hospitable to planting. How successful are these seeds in growing in that environment?

CHOWN: So, the large majority of Antarctica is covered in ice and in some places a very deep set of ice, indeed. But on the fringes of the continent, there, ice-free ground does occur. And in that area especially it's warm enough for seeds to establish. And a separate study undertaken by a different group had shown that what you would call in the U.S. annual bluegrass, or perhaps in the U.K. annual meadow grass, had in fact already established there on King George Island and elsewhere on the margins of the western side of the peninsula.

SIEGEL: When you say established there, do you mean that if we went around looking for it we might find some? Or it's very evident and you'd see patches of grass?

CHOWN: If you went to a couple of places at King George Island, you would see more than a few patches. You would think that perhaps you'd stumbled across a small lawn.

SIEGEL: Now, apart from altering or, from a scientific standpoint, contaminating the laboratory that is Antarctica, what danger is there in invasive species growing in Antarctica?

CHOWN: Well, currently the patches are small. But if you look just a small distance to the north, species that have been brought in by humans have not only managed to establish and grow, but they've also managed to spread tremendously. So, instead of having what you might expect as Antarctica or sub-Antarctic island, you have something that's more akin to a European grassland.

SIEGEL: Upon hearing the phrase invasive species in Antarctica, one reaction is - well, the most obvious invasive species there is us, it's human beings and the rest are just hitchhiking. Can we really have people going to Antarctica and expect there not to be a lot of other species that come along for the ride?

CHOWN: I think that you've identified the point quite clearly. As soon as humans are active in the area they have a chance of establishing other species. And that's true of all areas, not just Antarctica. Of course, it seems entirely unlikely that humans are going to stop their endeavors on this planet. So, given that, we have to look into methods to reduce the risks associated with our activities.

SIEGEL: Well, Steven Chown, thank you very much for talking with us about it today.

CHOWN: It's a great pleasure, Robert.

SIEGEL: Steven Chown is professor of Ecology at the University of Stellenbosch in South Africa, where he directs the Center for Invasion Biology.

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