Research Stories: The hunt for arctic aliens

Authors Ronja Wedegärtner and Jesamine Bartlett recall their team’s expedition in the high-Arctic Svalbard to monitor alien flora and publish their latest research which presents the most comprehensive survey of alien vascular species in the archipelago to date.

Whilst we do not hunt for extra-terrestrial aliens that may or may not be hidden under the ice (as some on the more unbridled sections of the internet would rather we did), hunting for terrestrial aliens is exactly what we do. And now, our team has developed a systematic method for just such a hunt in the Arctic.

Even at the height of summer, the Arctic is still a challenging place to live and work: as an icy wind is cutting through the derelict coal town of Pyramiden, we are slowly making our way over the rubble. Looking comically round in our layers, one would hardly think that it is August.

Summers in Svalbard are short, with often only one hundred days without snow. This leaves little time for plants to develop and little time for our field crew to map and find species that are alien to the windswept Svalbard archipelago at 74° North. But how did alien plants come here, to these arctic islands?

feature_high res_compressed — Virve Ravolainen (right) with Isabell Eischeid surveying the vegetation on Svalbard © Lawrence Hislop, Norsk Polarinstitutt

After centuries as a base for whalers and hunters, permanent settlements were established in the beginning of the 20^th century to mine for coal, and with the humans came animals and plants that are not part of this high-arctic ecosystem.

Locating and mapping alien plants requires us to move through a patchwork of abandoned houses and industrial sites, with more tactical thinking than you would ever expect of a biologist. A polar bear has been seen close to where we are mapping, so we keep our warning flares close, and a rifle loaded (as an absolute last resort).

At 20m in length, we can map each of these pixels in ten transects, but it takes three of us: two of us are walking with our eyes fixed on the ground, scanning for invaders, whilst another is standing guard, on the lookout for bears.

After an exhausting morning of combing through refuse behind the workshops of an old mine, we find the first colony of aliens in a former yard. It is the same in all the settlements, strikingly green lawns of foreign grasses, sometimes imported to make the otherwise brown and barren natural landscape feel more like home for its new human occupants, patches of meadow species around abandoned agricultural sites. In some places yellow carpets of dandelions trace the main routes taken by humans through the town centre.

P1040364 — A bank of non-native species established in disturbed soils in Barentsburg © Kristine Westergaard, NINA

All these locations are highly disturbed through trampling, traffic, and construction work that destroys the slow-growing native vegetation, reducing competition for establishing alien species. If an alien plant found their way North either through deliberate import, or stuck in the tread of a hiking boat, the settlements of Svalbard are primed to accommodate their colonization through such disturbances.

Sites we consider of high risk to establishment exist not only in settlements, but also in the seabird cliffs along Svalbard’s coast.

Nutrient rich guano, combined with increasing cruise tourists who come to observe the birdlife, makes this another scene for our alien hunt: as our Zodiac approaches the shore, we jump out in our dry-suits, wading to land with boxes of equipment, trying to keep our guns dry. Searching for alien species below the cliffs of Alkhornet the view takes our breath away, as lush green moss tundra and nitrogen rich meadows skirt the outcrops. It looks like there is potential.

Ossian Sars, Kongsfjorden – the soil found in these bird cliffs is rich in nutrients, and the conditions are well suited for alien plants to take hold. Many of the bird cliffs are also popular landing areas for cruise tourists © Kristine Westergaard, NINA

Yet so far, alien plants have not established themselves here. By systematically surveying both settlements and bird cliffs, we found 36 invasive plant species in total, but only in the settlements. And now that we have a repeatable baseline survey completed, we will know when any have established in the visited sites beyond the towns.

In ecosystems with such few species as the Arctic, alien plants compete with rare local flora and can change these unique ecosystems. Whilst many plants from the warmer South will not survive the harsh Arctic winters, global warming is happening twice as fast in the Arctic and so the probability of alien plants taking root here is constantly increasing.

It may take decades before the consequences of introduced species are detectable, and it is hard to say what effects these may take in the long term. But with all the pressures the Arctic already faces from climate change, increasing human activity, and associated biodiversity loss, we don’t want to take any chances by allowing invasive species to take hold. We have a window of opportunity to eradicate introduced species before they spread beyond control, but to do this we must evaluate our vulnerable landscapes on a regular basis.

Our study is the most comprehensive survey to date of alien vascular plants on Svalbard, and the method we propose for mapping and monitoring can be included in a regular evaluation that is useful for many Arctic areas. This is a job that is likely never over, or ever fully solved – we just need to keep hunting!

Currently there are no measures that prevent alien species from entering polar regions, so as visitors we must take responsibility and avoid becoming part of the problem. In the “Stop Arctic Aliens” and “Polar Alien Hunters” campaigns, researchers, the tourism industry and local governments have joined forces to inform people about what they should do before traveling to the Arctic and Antarctic. If you are visiting the polar regions, make sure you don’t bring any stowaways with you. Brush, vacuum and wash your bags, clothes, shoes and equipment before leaving home. Spread the word – and not the seeds!