keep non-native species out of Antarctica

In 2012, a group of scientists conducted a study in which they vacuumed the clothing and equipment of visitors to Antarctica – tourists, boat crews, researchers and others – before they disembarked from their planes or ships. .

The debris was then combed through for seeds and plant parts that could grow in the soil, revealing that participants were unwittingly carrying an average of 9.5 seeds and plant parts on their clothing and gear. Researchers bound for Antarctica tended to be bigger offenders than tourists, accounting for twice as many seeds on average.

“Oh my God, that was disgusting,” laughs Dana Bergstrom, an applied ecologist and senior researcher at the Australian Antarctic Program who took part in the study. “You don’t want to know what people put in their pockets!

The study highlights the role of humans in the spread of biological entities alongside our own movements: microbes on our skin, seeds stuck to our clothes, bedbugs in our food, barnacles on the hulls of boats. Many of these micro-travelers will not survive the journey or be able to thrive in the new environments they find themselves in. But some will take off and take over, claiming the niches of native species and altering ecosystems, often irreversibly.

For the most isolated continent and one of Earth’s most fragile ecosystems – Antarctica – this is beginning to pose major threats.

So far, Antarctica has seen few such invasions, thanks in large part to its extremely cold temperatures, lack of a resident human population, and accessibility – as well as careful monitoring by the through the Protocol on Environmental Protection to the Antarctic Treaty, which fully protects the continent as a natural site. Reserve. So far, only 11 non-native invertebrates and one grass have established themselves on Antarctic lands. Scientists have also seen non-native species in the marine environment but have yet to observe their full establishment, likely because it is too cold for them to survive and thrive.

This is fortunate: Antarctica’s native species are particularly unique, having adapted over millennia to survive in harsh conditions, and many are still unknown. Last year, scientists from Australia’s Monash University discovered a type of bacteria that derives its energy from hydrogen and is able to make its own water.

But as the planet warms – and Antarctica gets busier with more tourism, new research stations and reconstruction projects – there’s a growing chance that rogue species will find a foot and surpass their endemic counterparts. “Antarctica is lucky that not much has happened yet,” says Bergstrom.

Port Lockroy on the Antarctic Peninsula, a popular tourist destination. Paul Balfe, Flickr

However, things are changing very quickly, especially on the Antarctic Peninsula – the northernmost corner of the continent, which draws an elongated ‘S’ shape towards South America’s Tierra del Fuego. Sea temperatures now hover above zero degrees centigrade for around three months of the year, increasing the chance that a non-native species will complete its life cycle and become established.

“As climate change combines with non-native species, these biological barriers are starting to fray around the edges,” says Bergstrom. “We can see it, so can we prepare to stop it?” If these barriers no longer work, what else can we do? »

Map and mitigate incursion risks

One element of protection is to assess the likely origins of non-native species. In a just-published study, researchers from the University of Cambridge mapped shipping traffic to Antarctica from 2014 to 2018, which included tourist, fishing, research and supply vessels. They found that shipping connected the continent directly to all parts of the world, meaning that non-native marine species could potentially arrive from any part of the world.

Since most ships only visit Antarctica during the summer season, they therefore spend a lot of time elsewhere the rest of the year, picking up organisms like barnacles, mussels and algae on their hulls. Knowing where these ships are going can help with monitoring and risk assessment, says Arlie McCarthy, lead author of the study and a PhD student at the British Antarctic Survey. “If a ship has spent the last three years in the tropics and then makes a trip to Antarctica, its biofouling will likely be mostly tropical species, which are unlikely to survive the trip,” she says. “But if it’s a vessel that spends most of its time in cold water, like in the Arctic or southern South America, that poses more risk.”

Bergstrom calls for collective action by Antarctic Treaty member states to ensure that all vessels traveling to Antarctica are biologically safe. One way to do this, she says, is to run ships through the five main “gateway” cities to Antarctica – Christchurch, New Zealand; Hobart, Australia; Cape Town, South Africa; Punto Arenas, Chile; and Ushuaia, Argentina – where they can be cleaned, rather than relying on sea ice to scrape their hulls. “There have been quantum leaps in technologies for cleaning ship hulls, and ship design is improving, although we still have a lot of old ships,” she says.

Invasive species could even harm larger wildlife in the Antarctic region.  Long stem, Unsplash
Invasive species could even harm larger wildlife in the Antarctic region. Long stem, Unsplash

On land, his suggestions are similar: design studies that identify pathways through which species enter and create barriers preventing them from doing so. Since the aspiration study mentioned at the beginning of this article was conducted, several countries with Antarctic research programs, such as Australia and New Zealand, have established mitigation, for example by issuing designated Antarctic clothing and equipment that is not worn or used anywhere. other.

Once these types of barriers are in place, monitoring and early intervention mechanisms are essential to ensure that species that slip through the cracks cannot become established. winter grass, Annual poa, an invasive European weed that plagues golf courses around the world, has established itself on a number of sub-Antarctic islands and has traveled to the Antarctic Peninsula several times. “And every time, the international programs hammer it home,” says Bergstrom. “You can’t do this unless you have long-term monitoring programs backed up by rapid action.”

To Antarctica: Invasion or Evolution?

All ecosystems change over time and some newcomers will make it to the continent without human assistance. “We don’t want to stop the evolutionary process,” says Bergstrom. “But if you’re not sure it looks like a natural arrival, my argument is to take it out, because if it’s [natural], it will happen again. It’s better to be wrong on that side and have no regrets.

Germs are another matter: we all bring multitudes of them with us, and they are quite difficult to eradicate. Even COVID-19 arrived in Antarctica last year. ‘Reverse zoonosis’, where humans transmit diseases to animals, is a huge concern: penguin and seal populations could be particularly vulnerable to human-borne diseases.

“Right now there’s heightened focus: we have this precise moment to really protect Antarctica, and if we don’t get it right, it will follow the rest of the planet into homogenization,” Bergstrom says.

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