Under the Tundra’s Spell

The Arctic tundra is not only a place of untouched nature, but also a hotspot for ecological change. Researchers studying the fragile balance of the tundra are uncovering alarming signs: the disappearance of lichens and the increase in fires mark the start of a chain reaction with potential global consequences. Join ISTA PhD student Evgeniya Pravdolyubova and Ramona Heim from the University of Münster as they explore the shifting Siberian landscape.

“Whup-whup-whup,” the helicopter’s rotor blades roar. The wind lashes across Evgeniya Pravdolyubova’s face as the chopper prepares to land. Through the swirling dust stirred up by the rotors, researchers emerge, carrying big backpacks and duffels.

Not long ago, Evgeniya was a biology teacher; now she finds herself amidst the expansive Arctic tundra of the Russian Yamal Peninsula in northwestern Siberia. Boundless, untouched nature instead of classrooms. The sweet scent of rhododendrons and persistent mosquitoes instead of grading exams.

Into the wild

After landing, the researchers set up their base camp: a small tent city equipped with electric generators, microscopes, and mobile ovens, surrounded by steppes and trails. A few days later, they pack it up again and hop on the choppers to move deeper into the wild.

“The summer of 2018 was extremely hot,” Evgeniya recalled, which is why the new camp is set up a little closer to a lake. With special filters, the scientists prepare the water from the lake for drinking. When the filters become clogged, they switch to their hiking socks to drain the water through.

In the evenings, when it gets cold, the group gathers together. Over homemade tea made from fermented willow herb leaves, the scientists delve into the data they have collected to evaluate the reindeer’s grazing land.

By integrating satellite images of the distinct tundra areas with geobotanical descriptions, they map the relationship between plants and their geographical environment. They also analyze the species composition of mosses, lichens, grasses, and shrubs in the surveyed areas.

These data points help the expedition team to estimate the resources available for reindeer grazing during summer and winter, ultimately defining recommendations for reindeer management.

Reindeer and their grazing lands

Reindeer are an integral part of the indigenous population of the tundra. Ethnic groups like the Nenets, native to the Yamal Peninsula, engage in a lifestyle centered around reindeer herding throughout the year. These cloven-hoofed animals provide food and are utilized for making clothing and tools. The animals’ grazing practices and migration routes shape the Nenets’ way of life, their cultural identity, and their social structures. They are indispensable to their lifestyle, as they facilitate seasonal migrations in search of grazing land through the Arctic cold.

The tundra ecosystem is also adapted to reindeer. The grazing of these elegant deer influences plant growth and diversity, preventing any single species from dominating the landscape. For some time now, however, improved conservation efforts and more sustainable management practices have contributed to an increase in the reindeer population. This increase is also noticeable in the grazing landscapes.

Part fungus, part algae

According to Evgeniya, Cladina, or “ягель” (pronounced “yagil”) in Russian—a lichen group within the Cladonia genus, thriving here in the tundra—is affected. Especially, Cladonia rangiferina (reindeer lichen), a member of the Cladina subgenus and a crucial food source for reindeer during the bitterly cold winter months, is heavily impacted.

Lichens are peculiar organisms, a fascinating blend of fungus and algae. “They are symbiotic communities of fungi and photosynthetically active organisms such as green algae or cyanobacteria,” explains Evgeniya.

Evgeniya is an expert in the field of these organisms. During past summer months, while on school vacation, the then-teacher often took part in field trips and learned to identify birds and lichens. At an ornithology conference, she eventually met colleagues who were urgently looking for fungi experts to help them identify lichens in the tundra of the Yamal Peninsula in northwestern Siberia.

Now surrounded by the pleasant scent of moss, Evgeniya looks for reindeer lichens, which are easy to identify due to their gray, coral-like bodies, but hard to find. “Old school books describe findings of reindeer lichen specimens in the tundra with a height of 60 cm. Here on my expedition in Yamal, all the specimens I found were significantly smaller. There was only one on a peat bog that was around 40 cm high,” explains the scientist.

According to the biologist, the areas in Yamal are heavily overgrazed, and the regeneration of lichens is progressing slowly. The situation is further exacerbated by the effects of global warming and rising temperatures, which have led to widespread fires in the tundra in recent years.

Tundra fires?

In contrast to fire-prone ecosystems (for instance, the giant sequoia ecosystem of Yosemite National Park, USA), where regular fires play a crucial role in regeneration and maintaining ecological health, fires have historically been rare in most Arctic tundra regions.

This contrast highlights that while some environments regularly experience fires to which local forests have adapted, tundra ecosystems lack such adaptation. “Tundra ecosystems do not usually benefit from fires. When they occur, they tend to have adverse effects,” explains Dr. Ramona Heim from the Institute of Landscape Ecology at the University of Münster. “Instead, fires in the tundra often worsen the effects of climate change, release carbon, and can trigger changes in vegetation.”

Like Evgeniya, Ramona also visited the Siberian tundra in 2017 and 2018, as part of expeditions to the Tazovsky District, east of Yamal, to better understand the interplay between fires and tundra vegetation.

Arctic adventure: post-fire secrets of the tundra ecosystem

Ramona crouches to collect leaves from the dwarf birch Betula nana, placing them neatly on a plate to photograph them. Despite the warm summer conditions, the ecologist opts for a long-sleeved T-shirt to protect herself from mosquitoes. 

After finishing her sampling, Ramona and her colleagues walk several kilometers through dense and shrubby tundra terrain to return to camp, where a delicious warm meal of mashed potatoes awaits. In this corner of the world, the researchers store their food directly in the soil, which acts as a natural permafrost refrigerator.

In a current study, Ramona conducted a meta-analysis, which compiled field data from her trips to the Tazovsky District, as well as data from several fellow researchers, including Evgeniya, to explore trends in the long-term development of vegetation cover for five specific plant types following tundra fires.

Her findings, published this year in a mini-Review in the Journal of Ecology, indicate that after a fire in the warming Arctic, the tundra ecosystem may not always revert to its original conditions. The researcher and her colleagues suggest two primary development trajectories for the ecosystem following a fire. 

Tundra in limbo

One possible scenario is that woody vegetation, including shrubs and other woody plants, will become more dominant. The second scenario assumes that grasses will increase in abundance. Both of these new conditions can be reinforced by so-called “feedback mechanisms.”

“The woody-dominated state is, for example, reinforced by feedback mechanisms such as deeper soil thaw and longer growing seasons, which promote the establishment and growth of woody vegetation after fire,” Ramona explains her hypothesis.

“In contrast, the grass-dominated state is supported by feedback mechanisms that increase flammability, as grass litter accumulates and makes the landscape more prone to repeated fires.”

Overall, predicting precise changes in the tundra remains challenging due to numerous influencing factors and the lack of comprehensive data for much of the Arctic. Currently, Ramona suggests that any assessment of how alternative ecosystem states will evolve is speculative. Nonetheless, gaining a clear scientific understanding of potential developments can help decision-makers formulate better-informed decisions about fire management and land use.

A vicious circle with global consequences

For lichens in the tundra, however, the future does not look too bright. Both vegetation scenarios presented by Ramona and her colleagues assume that this dual organism will struggle to regenerate as temperatures increase and fires become more frequent. Even under present conditions, lichens are already finding it difficult to recover, partly due to the growing reindeer populations.

This situation impacts not only the ecosystems but also the Nenets and their traditional way of life, which depends on lichen-rich landscapes to sustain their reindeer herds. “The loss or reduction of lichen due to fire could therefore harm both the environment and the cultures that rely on it,” explains Ramona.

The Arctic tundra is in danger, leading to a potential global chain reaction. Increasing fire occurrences affect the permafrost, which stores large amounts of carbon. When permafrost thaws, more and more greenhouse gases are released into our atmosphere, which in turn further accelerates climate change, impacting the entire world. These challenges in the Arctic should not be viewed in isolation; they are a warning sign and a precursor to broader global environmental shifts. 

The sun casts a gentle glow on the silvery lichen, and the earthy scent of the soil lingers in the air. It is a vivid reminder of what is at stake and fuels the hope that landscapes like these continue to thrive for generations to come.

Publication:

Heim et al. 2025. Arctic tundra ecosystems under fire—Alternative ecosystem states in a changing climate? Journal of Ecology. DOI: 10.1111/1365-2745.70022