We tend to think of Antarctica as remote and remote – biologically speaking, that’s true. But the continent is busier than you probably imagine, with many national programs and tour operators criss-crossing the globe to get there.
And every ship, every cargo, and every person could harbor non-native species, hitchhiking to head south. This threat to Antarctica’s fragile ecosystem is what our new assessment, published today, addresses.
We’ve mapped the past five years of planes and ships visiting the continent, shedding light for the first time on the extent of travel across the hemispheres and potential sources of non-native species, as shown in the map below. We have found that fortunately, while some have broken through to Antarctica, they have generally not yet taken over, leaving the continent still relatively pristine.
But Antarctica is getting busier, with new research stations, reconstructions and more tourist activities planned. Our challenge is to keep it intact in the face of this increasing human activity and the threat of climate change.
Author provided
Life evolved in isolation
From a biodiversity perspective, much of the planet is mixed. The scientific term is homogenization, where species, such as weeds, pests and diseases, from one place are transported to another and become established. This means that they begin to reproduce and influence the ecosystem, often to the detriment of the inhabitants.
Most life in Antarctica is stuck on tiny, ice-free coastal swathes, and that’s where most research stations, ships, and people are.
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This includes unique animals (think Adelie penguins, Weddell seals, and snow petrels), mosses and lichens that harbor tiny invertebrates (such as mites, water bears, and springtails), and a array of microbes such as cyanobacteria. The adjacent coast and the ocean are also teaming with life.
The more we learn about them, the more exceptional life at the end of the planetary spectrum becomes. Just this week, new scientific findings have identified that certain Antarctic bacteria live in the air and make their own water using hydrogen as fuel.
EPA/YONHAP
When the Southern Ocean formed around 30 million years ago, natural barriers were created with the rest of the world. This includes the Antarctic Circumpolar Current, the strongest ocean current on the planet, and associated strong westerly surface winds, freezing air and ocean temperatures.
This means that life in Antarctica has evolved in isolation, with flora and fauna that usually exist nowhere else and can cope with freezing conditions. But the simplicity of Antarctic food webs can often mean that there are gaps in the ecosystem that other species around the world can fill.
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In May 2014, for example, routine biosecurity monitoring detected non-native springtails (tiny insect-like invertebrates) in a hydroponic setup at an Australian Antarctic station.
This station, an ice-free oasis, previously lacked these intruders, and they had the potential to permanently alter the local fragile ecosystem. Fortunately, a quick and effective response succeeded in eradicating them.
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Climate change pressures are exacerbating the challenges for human activity in Antarctica, as climate change brings milder conditions to these wildlife-rich areas, both on land and at sea.
As glaciers melt, new areas are exposed, giving non-Antarctic species a greater opportunity to establish themselves and eventually compete with locals for resources, such as nutrients and valuable space. and no ice cream.
So far we’ve been lucky
Our past research has focused on non-native propagules – things that spread like microbes, viruses, seeds, spores, insects and pregnant rats – and how they get carried away in Antarctica.
They can be easily caught on people’s clothing and equipment, fresh food, cargo and machinery. In fact, research over the past decade found that visitors who hadn’t cleaned their clothes and gear carried an average of nine seeds each.
Dana M Bergstrom
But few non-native species have established themselves in Antarctica, despite their best efforts.
To date, only 11 species of non-native invertebrates – including springtails, mites, a gnat and an earthworm – have established themselves in various locations in the warmer regions of Antarctica, including Signy Island and the Antarctic Peninsula. In the marine realm, some non-native species have been observed, but none are thought to have survived and become established.
Germs are another matter. Each visitor to Antarctica carries millions of microbial passengers, and many of these microbes are left behind. Around most research stations, human gut microbes from sewage have mixed with native microbes, including exchanging antibiotic resistance genes.
Read more: COVID has reached Antarctica. Scientists are extremely concerned about its wildlife
Last year, for example, a rare harmful bacterium, pathogenic for humans and birds, was detected in the guano (poo) of Adélie and gentoo penguin colonies at sites with high human traffic. COVID-19 also made its way to Antarctica last December.
Both of these cases risk what’s known as “reverse zoonosis,” where humans spread the disease to local wildlife.
Jonny Stark / AAD
What do we do about it?
Three factors have helped maintain Antarctica’s near-pristine status: physical isolation, cold conditions, and cooperation between nations under the Antarctic Treaty. The Treaty is underpinned by the Environmental Protocol, which aims to prevent and respond to threats and pressures on the continent.
The Antarctic Treaty countries are unanimously committed to preventing the establishment of non-native species. This includes adopting a non-native species science handbook, which provides guidance on how to prevent, monitor and respond to non-native species introductions.
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But time is running out. We need to better prepare for the inevitable arrival of more non-native species to prevent them from becoming established, as we continue to break down the barriers protecting Antarctica. One approach is to adapt the new 3A approach to environmental management: Awareness of values, Anticipation of pressures, Action to contain pressures.
This means stepping up surveillance, taking note of predictions about non-native species that might sneak through biosecurity and establishing themselves under new conditions, and putting in place pre-determined response plans to act quickly when they do. .
