Food imports bring aliens to Antarctica
11 April 2011, by Sara Coelho
Regular shipments of fresh meat, vegetables and other goodies are a godsend for all the scientists holed up in Antarctica's research stations, sometimes for months on end. But what's good news for the researchers very far away from home also means potential danger for frail ecosystems, as a new study finds.
Rothera Research Station, British Antarctic Survey.
The report, published in the journal Biological Conservation, shows that fresh food imports, with attached soil, seeds, microorganisms, insects and other invertebrates, can act as a highway into Antarctica for alien invaders.
The shipments come from all over the world, with transport times lasting from a few days to several weeks. 'Nations often source unwashed vegetables as they tend to keep longer than washed veg, so soil is often found on imported produce,' explains Kevin Hughes, an environmental scientist from the British Antarctic Survey and lead author of the report.
Hughes and his international team of scientists from the project 'Aliens in Antarctica' (part of the International Polar Year) set out to quantify how many alien species make their way to Antarctica hidden in the groceries.
The team examined more than 11,250 fruit and vegetables sent to nine research stations in Antarctica and the surrounding islands, including the UK's Rothera Research Station, Japan's Syowa Station and the South African SANAE IV. They measured the amount of soil present in each shipment, analysed the fruit and veg for fungal infections and looked out for alien invertebrates.
They found soil on 12 per cent of food items, and about 56 alien invertebrates including slugs, spiders, weevils and caterpillars. Many were still alive. The team also found 19 species of mould, including fungi known to have caused plant diseases elsewhere – although currently there is no evidence that they will cause similar harm to Antarctic species.
'The important outcome from this work is that we've shown fresh foods present a real risk and we now know the likely levels of alien species input by this pathway' says Hughes, stressing that his team only sampled a fraction of the fresh produce entering the region. By scaling up the results to all of the groceries imported to Antarctic research stations, 'we find we are importing a lot of soil, invertebrates and microorganisms, with broader biodiversity, from all over the world,' he adds.
Trying not to soil Antarctica
This is not the first time soil has been implicated in introducing alien species to the Antarctic. Back in the 1960s, a vegetation transplant experiment on Signy Island led to the establishment of a colony of the flightless midge Eretmoptera murphyi.
More recently, annual meadow grass (Poa annua) has gained a foothold on King George Island, at the northern tip of the Antarctic Peninsula. The islands around Antarctica have already over 200 alien plants and animals, including rats, cats and mice, although the continent itself has been colonised by fewer than ten alien species.
Hughes wants to reduce further the risk of species introductions: 'We want to keep Antarctica as a pristine area, unimpacted by human activities, including introduction of alien species,' he says.
This is particularly important given the frailty of Antarctica's ecosystem. The region has very low biodiversity, although some areas, particularly on the northern Antarctic Peninsula, are rich in mosses, lichens, and invertebrates. The lack of predators and competition mean that the local plants and animals are ill-equipped to deal with invasive species.
The current trend of climate change towards warmer temperatures is not encouraging either. 'The Antarctic Peninsula is heating up at one of the fastest rates globally,' says Hughes. With warmer temperatures and greater water availability Antarctica becomes less extreme and as a result introduced alien species may find it easier to survive and become established. 'Unless we take practical action now, Antarctica's unique ecosystems may be damaged irretrievably,' he adds.
Hughes, K.A., et al. Food for thought: Risks of non-native species transfer to the Antarctic region with fresh produce. Biological Conservation (2011), doi:10.1016/j.biocon.2011.03.001
The paper includes a list of recommended measures to reduce the risk of introduction of non-native species associated with fresh food imports.
Interesting? Spread the word using the 'share' menu on the top right.