Are Antarctic visitors introducing invasive alien plant species?

by British Antarctic Survey on 19 Mar 2012 Seeds attached to visitors’ (including sailors') clothing and bags may introduce invasive alien plant species that could damage the Antarctic continent’s ecosystems, according to information published in the journal Proceedings of the National Academy of Science (PNAS) this week.

An international team of scientists, including environmental scientist Dr. Kevin A. Hughes from the British Antarctic Survey (BAS), sampled, identified and mapped the sources and destinations of more than 2,600 plant propagules—structures like seeds or plant fragments that allow plant to establish—hitching a ride to Antarctica on scientists and tourists during 2007-2008.

The researchers assessed the likelihood that these alien species would survive and establish in Antarctica, both now and by the year 2100, using current climate data and projections based on emission scenarios from the Intergovernmental Panel on Climate Change (IPCC).

Invasive alien species are among the primary causes of biodiversity change worldwide. Lead author Prof. Steven Chown, Director of the DST-NRF Centre of Excellence for Invasion Biology based at Stellenbosch University in South Africa said, 'We wanted to assess the risks for Antarctica as a whole, by finding out which seeds are being brought in, where they originate from and where they are most likely to establish.'

Although the authors found that the average visitor carries less than ten seeds to the Antarctic, several alien species have already become established on the Western Antarctic Peninsula, in a region where future climate-related changes along the coast are likely to aid the plants’ survival. Furthermore, because travellers often visit other cold places prior to arriving in Antarctica, as many as half of the alien propagules that reach the continent are from cold-adapted species that could withstand conditions at some Antarctic destinations.

The findings, along with others in the study, represent a comprehensive risk assessment of invasive species in Antarctica and a blueprint to mitigate future threats. The study highlights the risks posed by invasive species, even in remote areas, and how these risks may grow with climate change.

Dr. Kevin A. Hughes, at BAS says, 'Crucially, the data in this study will inform management decisions aimed at conserving Antarctica’s biodiversity from invasive alien species. In the future, increased numbers of tourists and scientists are expected to visit the continent, so as a community we need to implement effective practices to reduce the number of alien species getting there.'

The study was a consortium effort of the International Polar Year (IPY 2007–9) ‘Aliens in Antarctica’ project. In practical terms, about 2% of the 33,000 tourists and 7,000 scientific team members who visited Antarctica in 2007 during the first season of IPY were sampled and asked questions about their previous travel. The process included the fine-combing and vacuuming of camera bags, outer clothing and other baggage.