What is tundra?
The Arctic tundra is one of the large terrestrial natural systems (biomes) on Earth. The tundra is found where the summer climate is too cold for forests to grow – that is, colder than 10-12 degrees Celsius in July.
Such cold areas are found either above a certain elevation in the terrain to the south (alpine tundra/high mountains) or all the way down to the coast in the northern regions (Arctic tundra).
Much of the Arctic tundra has permafrost – that is, constant frozen ground. However, permafrost is not a defining criterion for Arctic tundra.
In some places - like in Finnmark and southern Greenland - the tundra mostly lacks permafrost. On the other hand, there is permafrost in large parts of the northernmost forest in Siberia and in North America.
Frost processes can create much exciting landscape in the tundra.
Photo: Rolf A. Ims
The tundra comprises large flat expanses north of the Arctic treeline.
Photo: Geir Vie
Signs of permafrost are often seen in the form of such rock formations on the tundra. This occurs sporadically in higher elevation areas on the Varanger Peninsula.
Photo: Rolf A. Ims
Boundaries and zones
Globally, the Arctic tundra forms a relatively narrow belt between the subarctic forest to the south and the coast against the polar seas to the north.
The tundra belt is divided into two main zones – high Arctic and low Arctic tundra. The boundary between the two tundra zones is where the summer climate is too cold for continuous vegetation of dwarf shrubs. Heaths dominated by crowberry, blueberry, and dwarf birch, therefore, do not exist in the high Arctic.
The transition zone between subarctic forest and low Arctic tundra is often gradual and is called forest tundra. The forest tundra has sparse stands of low-growing trees – in Finnmark typically mountain birch.
The northernmost mountain birch forest in the border zone to the Arctic tundra is called forest tundra.
Photo: Geir Vie
The map on the left shows the distribution of the high Arctic (pink), low Arctic (light green), and subarctic (green) zones. The Arctic treeline (dark green) separates the low Arctic from the subarctic and crosses the Varanger Peninsula.
Source: Arctic Monitoring and Assessment Programme (AMAP)
Low arctic tundra in Finnmark
On the Norwegian mainland, Arctic tundra is only found on the peninsulas in East Finnmark. The largest area is on the Varanger Peninsula, where there is low Arctic tundra.
The vegetation varies with the substrate (soil type, moisture, bedrock) and altitude above sea level. Low-lying tundra on nutrient-rich, moist ground along the coast and in the valleys can have lush meadows and tall willow thickets.
Higher elevation and nutrient-poor areas have a lot of heath with a dominance of dwarf shrubs (heather and low-growing dwarf birch).
At higher altitudes, it is colder, and the vegetation is more exposed to weather and wind. Here it is mostly heather and dwarf birch.
Photo: Leif Einar Støvern
Tall willow thickets are often found at the bottom of the lush river valleys on the Varanger Peninsula.
Photo: Geir Vie
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The blue areas on the map above show the distribution of low Arctic tundra in East Finnmark. The green areas are forests in the transition zone (ecotone) between the Arctic and subarctic climate zones – the so-called forest tundra. The remaining gray area represents regions within the forest tundra ecotone that are not forest (mainly alpine tundra).
Food Chains and Functions of the Ecosystem
Tundra ecosystems have several intertwined food chains - a so-called food web.
These have three levels – plants, plant-eaters (herbivores), and meat-eaters/predators (carnivores/predators). Plant growth, which constitutes the primary production in the food web, is low due to the cold and short growing season. The soil contains a lot of stored carbon because the decomposition of dead plant material is limited by low temperatures. Thus, the tundra plays an important role in the relationship between carbon bound in the soil and carbon-containing greenhouse gases in the atmosphere.
The network of food chains (food web) on the low Arctic tundra forms three levels with plants, herbivores, and predators. Some of the terrestrial food chains are also linked to marine and limnic (freshwater) food chains.
Arctic species and biological diversity
The tundra has a low number of species compared to most other ecosystems on the planet. However, the biological diversity of the tundra is unique because many of the species are found only in Arctic or alpine ecosystems.
On the Varanger Peninsula, this includes species such as the Norwegian lemming, rock ptarmigan, Arctic fox, long-tailed skua, and snowy owl. Some plant species that are otherwise typical of the Arctic, such as the Svalbard poppy and Tundra sandwort, are found here on the Varanger Peninsula as the only place on the Norwegian mainland.
If you want to learn more about the research we do on, among other things, ptarmigan, Arctic fox, and small rodents – read on about our focus areas.
Photo: Long-tailed skua: Rolf A. Ims, Rock ptarmigans: Geir Vie, Snowy owl: Geir Vie, Lemming: Rolf A. Ims, Svalbard poppy: Leif Einar Støvern, and Arctic fox: Laurent Demongin.
