Antarctic invasive plants: why rapid action matters

At the close of 2025, researchers discovered a lone clump of tussock grass growing where it should not have been in Antarctica. Within weeks, they had pulled it out and regarded the matter as settled. Antarctica’s environmental rules were intended to deliver exactly that sort of swift, straightforward response.

Those rules have been in force since 1991. Yet elsewhere on the continent, a scruffy lawn weed has grown near a research station since 1984, and attempts to eradicate it continue. A new study set out to understand the difference between the two outcomes.

Antarctic stowaways

Non-native plants arrive in Antarctica much like other unwanted travellers: they hitch a lift. Mud on a boot, a seed caught in Velcro or soil stuck to a shipping container can all transport life from one hemisphere to the bottom of the world.

Once they arrive, a handful of hardy species can gain a foothold in the relatively warm coastal pockets.

Kevin A. Hughes of the British Antarctic Survey (BAS), a co-author of the study, has followed the issue for decades.

His previous research recorded hundreds of introduction events across the region, involving more than a hundred species. Most arrivals were spotted early and removed by hand, or died in the cold.

Around 20 non-native species have established themselves and survived, almost all of them small invertebrates rather than plants.

They are concentrated on the Antarctic Peninsula and nearby islands, the mildest part of an otherwise harsh continent.

Antarctic grass under scrutiny

Annual meadow grass, the tenacious lawn weed scientists call Poa annua, is the plant that repeatedly appears in the Antarctic record.

It is the sort of undemanding grass that grows in pavement cracks at home and spreads quickly, qualities that make it troublesome on fragile polar ground.

At a Polish Antarctic research base on King George Island, the invasive grass entered a protected area and became established. Teams first noticed it in the mid-1980s, but a slow response allowed it to settle. Decades later, eradication work continues, with no clear end in sight.

By contrast, a single clump of tussock grass discovered on sub-Antarctic Signy Island in late 2025 was removed within weeks of being noticed.

Speed makes all the difference. Removing one clump can take an afternoon; leave it too long and the plant can become a permanent resident.

Warming creates opportunities

Climate change is quietly changing the odds.

As coastal Antarctica becomes warmer and wetter, conditions that once killed most stowaway seeds on arrival may allow more of them to establish themselves.

Almost two-thirds of the experts interviewed for the study identified warming as a force likely to make the problem worse.

More visitors, greater risk

Increasing visitor numbers add to the danger. Scientists, support staff and a growing flow of tourists can all carry seeds unintentionally.

One recent paper found that introduction rates had not risen as quickly as visitor numbers, suggesting biosecurity checks have some effect. Even so, new arrivals continue to increase.

Researchers regard plant management as urgent rather than hypothetical because of that combination of a thawing coastline and sustained human traffic.

The plants present today are the relatively easy things to remove. What may follow is a greater concern: invertebrates spread faster and are much harder to eradicate than grass.

Policy meets reality

To explore why responses are often slow, the study’s lead author, Ondrej Gomola of Lund University in Sweden, joined Hughes in interviewing seventeen Antarctic specialists.

They spoke to policymakers, field scientists and people who had personally removed plants on the ground.

Antarctica has no single government. It operates under the Antarctic Treaty, a 1959 agreement now binding nearly 60 countries, and major decisions require agreement from everyone at the table. That consensus principle protects the continent, but it can also slow action to a crawl.

The interviews revealed a system sustained by a small group of dedicated people. Working between science and policy, these experts can recognise a new plant and know whom to contact.

The difficulty is that there are so few of them, and their knowledge is distributed unevenly among countries with very different budgets.

Countries take different approaches

Nations do not all view non-native plants in the same way. One interviewee divided them into three groups: those that recognise the problem and act, those unaware of it, and those that know about it but are not particularly concerned. That difference in attention influences everything that follows.

Funding and staff account for much of the variation. A large national programme may deploy specialists able to recognise an unfamiliar seedling on sight, whereas a smaller programme may have people juggling wide-ranging duties and nobody specifically watching for invaders. Smaller operations also face a greater risk of an accidental slip.

The study identifies a more uncomfortable pattern as well. Some countries favour conspicuous gestures that benefit their reputations while overlooking the unglamorous but essential work of inspecting cargo and surveying the ground around their stations.

As the researchers point out, signing up to a rule on paper is not the same as putting it into practice.

Acting alone and quickly

One result challenged the researchers’ expectations. In most international systems, a country acting alone is a sign that something is wrong.

In this case, unilateral action proves to be an advantage rather than a defect, at least when grass plants must be removed in Antarctica.

Waiting for complete agreement can waste the crucial early window, so the Treaty quietly permits an individual country to remove a non-native plant on its own.

As one policy expert put it, “I doubt that any Parties would be concerned if another Party had taken [non-native plant removal] action without consultation.” When a clump is spreading, speed can matter more than coordination.

That flexibility has delivered tangible successes, including the removal of meadow grass at Cierva Point on the Peninsula after years of neglect.

The more fundamental gap concerns information. Countries seldom report their actions, leaving nobody with a clear account of what works and what is left undone.

Common ground on the ice

Before this study, nobody had mapped out precisely why Antarctic plant control falters and where it succeeds in the words of those doing the work.

The interviews uncovered a hopeful point within a tense system: non-native plants are among the few issues over which almost no country argues.

That shared concern is rare in a treaty system strained by geopolitics, with members increasingly divided over fishing, tourism and territory. It is also useful.

The researchers suggest it could provide a starting point for rebuilding cooperation: a technical problem countries can address together while larger disputes remain frozen.

The task is now being framed differently. Pulling weeds at the bottom of the world may seem minor, but acting early through better reporting, shared training and reliable funding is how a thin green threat can be kept thin.

There are still few plants. For now, the opportunity to keep their numbers down remains open.