With nearly every nook and cranny of the earth now accessible to humans, the world’s largest desert, Antarctica, is no exception. Statistics from the International Association of Antarctic Tour Operators (IAATO) show that over 50,000 people visited the frigid but warming area over the 2010-2011 time period. Of the many impacts that increasing numbers of tourists have on the area, the proliferation of plants on the continent is often not thought of as a major one. However, as a recent BBC articles points out, each visitor carries an average of 7.5 seeds to Antarctica. Scientists carry more, presumably because they have been out interacting with nature and picking up various seeds and tiny animals. Ideal places where the seeds attach are the tongues of boots, but they have also been found in and attached to bags and on clothing.
Only about 1% of Antarctica is ice free (that percentage is increasing as the climate warms) but tourists tend to make stops at some of the more ice free and warmer spots, thereby giving the seeds they carry with them a nice place to get settled. These invasive species are already getting a foothold in these warmer spots, competing with local species. As the BBC article points out, the seeds are from various regions of the world and many can survive in the colder climate at the south pole.
The researchers found that although many of the seeds originated in South America, a large number came from the Northern Hemisphere. About half of them came from cold regions and would probably be viable in the warmer bits of Antarctica. The researchers also collated evidence from other scientists on organisms that have already established themselves. Deception Island, 100km north-west of the peninsula, has already been colonised by two grass species and two springtails – tiny animals that live in topsoil and leaf litter. On the western slopes of the peninsula itself, the grass species Poa annua has established itself close to four research stations – implying that it has probably been brought, inadvertently, by visiting scientists. Poa annua has already taken over several sub-Antarctic islands where it dominates vegetation.
All this begs the question that surrounds our daily actions and interactions with the planet we live on: are humans the most invasive species?