Shrub tundra

Tundra is a treeless habitat, dominated by mosses, lichens, herbs and low shrubs, characteristic for arctic and subarctic regions, where the subsoil is permanently frozen (permafrost). The term is also used for physiognomic similar habitats in alpine areas above the timberline, but here it only refers to arctic and subarctic habitats.

Shrub tundra is a tundra type of the southern arctic belt characterized by abundance of medium small and small shrubs, especially Ericaceous species. This in contrast to the colder tundra of the middle and northern arctic belts, where mosses and lichens dominate (type F1.2). Permafrost is sporadic within the southern arctic, with mean temperatures of about 0 °C, and average July temperatures below 10 °C . Shrub tundra is a circumpolar arctic type of the tundra’s of Russia, Canada, Alaska and Greenland. In Europe the arctic zone (above the climatic limit of woodland) is mainly found in Russia, but small areas occur on the northern edges of Iceland and Norway, as well as on the islands Jan Mayen, Bjørnøya and the Svalbard archipelago.

In Finnmark, the northern region of Norway, the arctic belt is restricted to the lower altitudes at sea level. Dominant dwarf shrubs here are Empetrum hermaphroditum, accompanied by Salix herbacea , Vaccinium myrtilus, Vaccinium uliginosum, Juncus trifidus, Festuca vivipara and high abundance of mosses (Racomitrium lanuginosum, Dicranum fuscescens) and lichens (Cetraria cucculata, C. ericetorum). The habitat forms a gradual transition towards heathlands of the lower alpine zone, with a similar species composition (habitat F 2.2a ‘Alpine and subalpine ericoid shrub’). Differences between tundra and alpine heathland are the shorter growth period and lower soil temperatures in the arctic. Due to grazing (reindeer, rodents) the heathland occurs in mosaic with grasslands. Overgrazing leads to disappearance of lichen cover and specific species, like Cladina stellaris.

On Island, the same shrubs are characteristic of the tundra belt and, like in Norway, the transition towards boreal subalpine heathlands (habitat type F2.2a) is gradual. On young lava fields of Island vascular plants occur only scattered, and such pioneer stages of the habitat, dominated by the moss Racomitrium langinosum, sometimes accompanied by R. ericoides, are considered part of the shrub tundra.

Also on Jan Mayen, situated in the middle arctic belt, Empetrum hermaphroditum is the dominant species, growing together with the mentioned Racomitrium species and lichens. Here the type is found in a low, oceanic part of the island and – in contrast to other areas – there is no grazing.

On Svalbard shrub tundra is restricted to the warmest part of the island Spitsbergen, the “Innerfjord zone”. This comprises the coastal regions of the central fjords of Spitsbergen, where no sea fog and relatively few clouds result in a slightly warmer climate. Here about 75% of all vascular plants of Svalbard is found. Locally, shrub dominates the tundra. Here, the habitat type is considered a relict vegetation of post-glacial warmer periods. Empetrum nigrum and Vaccinium uliginosum are the most important species, and here and there Betula nana and Rubus chamaemorus are found. In the same part of Svalbard low shrubland dominated by Cassiope tetragona forms a transition to Moss and Lichen Tundra (F1.2).

Indicators of quality:

In good conditions the habitat shows the following characteristics:

• Dominance of dwarf shrubs,
• No indication of overgrazing,
• No erosion patterns,
• No presence of non-native species (like Lupinus nootkatensis),
• High cover and high diversity of lichens and mosses.

Synthesis of Red List assessment

Confidence in the assessment

Pressures and threats