Aliens in Antarctica?

In the news last week–a disturbing report on the number of seeds being brought into Antarctica by tourists, scientists and support staff.  Why is this a problem?  Let’s look at page 5 of the Google results to find out.

ImageOn Blogrunner we find that the average person carried around 10 seeds with them to Antarctica, but scientists usually had more than tourists!  Given that tens of thousands of people visit Antarctica each year, that adds up to a lot of foreign invaders.

The Japan Times tells of an invasive grass species called Poa annua which is colonizing the coastal ice free areas of Antarctica.  This grass could upset the ecological balance and dominate the native species.

The Global Invasive Species Database provides an extensive list of alien species found on the Malvinas, which are considered sub-Antarctic islands.  The list includes Ammophila arenaria or Marram grass and Berberis buxifolia (Darwin’s Barberry.) Both these plants are also considered noxious weeds in New Zealand, by the way.

DVice tells us that the largest number of incoming seeds found were from the colder regions of the Northern Hemisphere and South America.  That means the seeds would have little trouble becoming established in Antarctica, especially with the effects of climate change.

And seeds are not the only invaders.  John Priscu, quoted in National Geographic News tells us that the McMurdo Dry Valleys are being contaminated with human bacteria and bacteria from other regions of Antarctica.  Seals and penguins have been infected with human bacteria from the McMurdo Base sewage treatment plant! Some people are arguing for stricter controls on ice-covered lake drilling because of the danger of bacterial contamination.  While some scientists are unconcerned due to the likelihood that any introduced bacteria would not thrive in such a harsh environment,  Priscu  warns, “The thing is, we’re finding more and more extremophiles out there.”

And finally, from the Scar (Scientific Committee on Antarctic Research) Biodiversity in the Antarctic report: “From a terrestrial and freshwater perspective, the low energy environment and isolation of Antarctica mean that it is species poor. Indeed, terrestrial and freshwater systems of Antarctica represent the endpoint of the global gradient in diversity. Where life can exist, richness is typically low, and continental Antarctic systems represent some of the simplest in the world.”

Invasive species may destroy that simplicity once and for all.

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2 comments

  1. Interesting – I have always wondered about the ethics behind visiting such remote environments. On the one hand, it exposes people to them and helps them to appreciate the environments for what they are, but on the other the threat of invasive species is a big risk! Would be interesting to hear how some eco-tourism ventures go about preventing such colonisations. I know Heritage Expeditions have a very rigorous quarantine procedure, but how good are the larger vessels at keeping foreign invaders contained?

  2. The abstract of the orginal study by Chown et al says: “Visitors carrying seeds average 9.5 seeds per person, although as vectors, scientists carry greater propagule loads than tourists. Annual tourist numbers (∼33,054) are higher than those of scientists (∼7,085), thus tempering these differences in propagule load.” The article based on the study gives some strategies for preventing the transport of alien species, but just like NZ and the spread of didymo, it doesn’t take too many people who can’t be bothered before there is a real problem.

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