Aliens In Antarctica!

When researchers noticed two unusual plants growing along the shores of Whalers Bay on Antarctica’s Deception Island in January, 2009, the discovery posed a perplexing problem: Were they newly-noticed natives to be cataloged and celebrated – or potentially damaging invaders to be quickly exterminated? Now, a new study is offering a roadmap for distinguishing Antarctica’s native species from newcomers, and keeping the coldest continent free of alien invasions.

Antarctica’s “terrestrial and freshwater environments currently have few established non-native species compared to the sub-Antarctic islands and other terrestrial ecosystems on Earth,” Kevin A. Hughes and Peter Convey of the British Antarctic Survey note in the Journal of Environmental Management. “This is due to a unique combination of factors, including Antarctica’s remoteness, harsh climate, physical geography and brief history of human activity.” Indeed, just a handful of non-native grasses or insects are known to have become established in Antarctica – often in and around research bases – and many were quickly exterminated.

But the arrival of thousands of researchers and tourists – and a warming climate – are making it more likely that non-native organisms could gain a toehold, warn Hughes and Convey. And that poses “a dilemma for scientists and environmental managers,” who will need to determine whether a newly-noted species is: “(a) a previously undiscovered long-term native species, (b) a recent natural colonist or (c) a human-mediated introduction. A correct diagnosis is crucial,” they add, since the Antarctic Treaty requires conserving natives or “natural colonists,” but eradicating species carried in by human visitors.

To tell the difference, the two researchers suggest systematically considering a range of biological and historical evidence. Fossils, for instance, might reveal if an organism is a long-term resident, while historical surveys might turn up sightings by early explorers. Careful study of habitats, reproductive strategies and genetic diversity might also help separate old timers from newcomers. Answering “many of the questions will require input from specialists,” they note.

But what if even the experts can’t be sure? “Where doubt remains, a precautionary approach should be applied, but only after considering any implications for the colonized terrestrial and freshwater Antarctic ecosystem,” they write.

That’s exactly what happened along Whaler’s Bay. In January 2010, Hughes and Convey were called in to determine if the two unusual plant species deserved protection or extermination. By the time they arrived, however, one of the species was gone – “probably having been washed away by a nearby meltwater stream.” And they were unable to decide if the other had arrived by itself – or with some help. So “the precautionary principle was adopted… and all visible plant material was dug up and either destroyed or removed” — and added to the Antarctic Survey’s Herbarium.

“It is to be hoped,” the authors conclude, “that the Antarctic community as a whole can appreciate the serious threat to Antarctic ecosystems posed by invasive species and act together to take appropriate and effective mitigating action.” David Malakoff | September 25, 2011

Source: Hughes, K., & Convey, P. (2012). Determining the native/non-native status of newly discovered terrestrial and freshwater species in Antarctica – Current knowledge, methodology and management action. Journal of Environmental Management, 93 (1), 52-66 DOI: 10.1016/j.jenvman.2011.08.017

Image © Yan Keung Lee |