Arctic Alien Species Could Survive in Today’s Climate

Invasive species do not have to arrive in large numbers to create serious problems. In some cases, a single resilient newcomer can encounter suitable conditions, spread unnoticed and begin displacing native plants that cannot compete.

For this reason, the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) identifies non-native species as a significant danger to biodiversity worldwide.

A research team has now examined a straightforward but important question: if alien plant species were to arrive in the Arctic, which could survive under its current conditions? Their findings were striking, with many more potential survivors than most people might anticipate.

“We found a total of 2,554 species that would find a suitable climatic niche in today’s Arctic,” said Kristine Bakke Westergaard, an associate professor at the Norwegian University of Science and Technology (NTNU) University Museum.

Put simply, thousands of non-native plant species could potentially establish themselves in Arctic climates if they are transported to the region.

How plants could reach the Arctic

The Arctic’s isolation once provided a degree of protection, effectively acting as a natural quarantine. However, that barrier is rapidly becoming less effective.

Growing shipping activity, tourism, research and infrastructure development all raise the likelihood that seeds and plant material will be carried north on footwear, vehicles, freight or soil attached to equipment.

“Our results show that alien species from virtually all over the world can find a niche in the Arctic. And with all the human activity in the Arctic now, there are lots of opportunities to get there,” Westergaard said.

The concern is not merely that a plant arrives. What matters most is when it is detected. New species that establish themselves before being noticed can become invasive - spreading and damaging ecosystems - while officials may still regard them as little more than a novelty.

The search for likely invaders

Rather than concentrating on a single nation or habitat type, the researchers conducted a horizon scan. This forward-looking assessment is designed to identify threats before they become real-world problems.

“We looked at roughly 14,000 known alien plant species that can spread to places where they do not originally belong,” Westergaard noted.

The work brought together a vast range of evidence, including biodiversity database records, published studies and data from GBIF (Global Biodiversity Information Facility).

These occurrence records enabled the team to compare the locations where species currently grow with climatic conditions throughout the Arctic.

A plant that already persists in areas with comparable temperatures and seasonal patterns is more likely to cope with Arctic conditions, particularly as the region becomes warmer.

Where the Arctic looks most vulnerable

Mapping the findings revealed patterns that are relevant to land managers. The climates of certain Arctic locations could support considerably more potential invaders than others.

“Our map shows hotspot areas in the Arctic where many alien species can tolerate the climate. The highest number of species are found in the north of Norway,” said study lead author Tor Henrik Ulsted, a master’s student at NTNU Museum.

This does not mean that other parts of the Arctic are free from concern. The research indicates that there are few genuinely “safe” areas, only places where the risk is comparatively lower.

Even the high Arctic is not exempt. Svalbard, frequently viewed as an exceptionally remote outpost, was still identified as vulnerable in the scan.

“Even in Svalbard, 86 alien species can find a climatic niche,” Westergaard said.

Warming temperatures widen the door

The issue is particularly pressing because conditions in the Arctic are changing rapidly. Higher temperatures, extended growing seasons and altered precipitation patterns can shift a species from being unlikely to survive to having the potential to spread.

The researchers say that if the present-day Arctic can already sustain thousands of possible newcomers, an increasingly warm Arctic may be able to support still more. It is comparable to enlarging the guest list while also opening additional entrances to the house.

A central feature of the study is its practical value. It is one thing to state that invasive species pose a threat, but quite another to show people which species to monitor, where they may appear and why they present a concern.

The Norwegian Biodiversity Information Center has expert committees that evaluate risks in Norway and Svalbard. Yet compiling a useful shortlist of new potential invaders has proved difficult.

“These committees have long found it to be very laborious, almost impossible, to make a list of relevant species that should be assessed as possible new alien species,” Westergaard said.

Tools for assessing the threat

The new approach is intended to reduce that burden by supplying experts with a climate-based list of candidate species, allowing them to direct attention where it is most likely to be useful.

The next stage involves the detailed assessment: evaluating ecological effects, the likelihood of spread and the potential cost of taking action or doing nothing.

“Our long-term goal is to help identify alien species before they become invasive and problematic,” Ulsted said.

This emphasis on early action is important, as invasive species are famously difficult to manage once they have become established.

Prevention, early detection and a swift response generally prove more effective - and less expensive - than attempting to tackle a fully developed invasion later.

A looming policy deadline

The research also aligns with wider international ambitions. Westergaard highlights targets such as the Kunming–Montreal Global Biodiversity Framework, which calls for reductions in the introduction and establishment of alien species.

Norway has also adopted its own action plan intended to limit damage caused by alien organisms.

However, the main point is not administrative. The Arctic is no longer too isolated for invasion, while its climate is becoming increasingly hospitable.

Identifying the species most capable of thriving there is one of the few ways to stay ahead of the issue - before a “possible future invader” becomes a “permanent resident.”