Red List habitat classification > RLH - Sparsely vegetated habitats > RLH2.2 Boreal and arctic base-rich scree

Boreal and arctic base-rich scree

Quick facts

Red List habitat type code RLH2.2
Threat status
Europe Data Deficient
EU Data Deficient
Relation to
Source European Red List habitat factsheet
European Red List of habitats reports
European Red List of habitats (Excel table)


This habitat type is connected to calcareous rock types, such as limestone, dolomite or calcareous siltstone. The habitat type extends from the southern boreal region to the arctic zone and harbours therefore large diversity of species and plant communities. Screes (or talus formations) are formed when rock fragments fall off from cliff faces as a result of physical and chemical weathering and erosion. Screes often show a sorting of rock fragments. The largest blocks roll down the furthest, whereas the finest material accumulates in the uppermost part of the slope. Most occurrences of this habitat type probably represent scree slopes but also flat baserich gravel or blockfields may have been formed by frost action breaking calcareous rock outcrops in situ.

Baserich or calcareous screes are distributed mainly in the Scandinavian Mountain range, Iceland and Svalbard. In Iceland the division between baserich and basepoor scree habitats is not as clear as elsewhere in northern Europe, but the species composition on more-or-less neutral screes fits best in the here described habitat type.  The sparsely vegetated flat, stony and sandy volcanic habitats of Central Island are included in type H5.1c.

Similar to siliceous screes, the vegetation of baserich screes varies in the boreal region from forests to scrubs and sparsely vegetated, unstable patches, if considered as a whole. However, the habitat type in question only refers to more or less open patches that do not have a tree or scrub layer. In screes, the most characteristic assemblages of vascular plants are found in the unstable patches, where also weak competitors or various pioneer communities can persist. On calcareous substrate, characteristic plants are Arenaria humifusa, A. norvegica, A. pseudofrigida, Artemisia norvegica, Papaver species of the Papaver radicatum group, Papaver relictum, Papaver laestadianum and Braya linearis.

The most important factor determining the species composition of screes is natural or seminatural disturbance regime, which maintains characteristic species assemblages. In screes, the disturbance regime is characterized by the continuum of periodic rockfall, unstability of the substrate, and in some regions also by the long tradition of grazing. In some cases, grazing or, e.g., hiking or mountaineering activities may cause additional erosion in the habitat to such an extent that it disturbs the formation of typical vegetation.

Indicators of good quality:

·      natural or seminatural disturbance regime, with a continuum of periodic rockfall and unstability of the substrate or (in some cases) forest fires

·      no or little succession towards scrub and forest

·      continuation of traditional grazing (where relevant)

·      no disturbance (for example by hiking, grazing, etc.)

·      diversity of lichen, moss and vascular plant species

Characteristic species
For full habitat description, please download the habitat factsheet.

Threat status

Synthesis of Red List assessment

Due to lack of quantitative data for most of the distribution range the habitat is assessed as Data Deficient (DD).
Red List Category Red List Criteria
Data Deficient -
Red List Category Red List Criteria
Data Deficient -

Confidence in the assessment

Red List of habitat categories and criteria descriptions

Pressures and threats

  • Sylviculture, forestry
    • Forest planting on open ground
    • Forest and Plantation management & use
  • Urbanisation, residential and commercial development
    • Dispersed habitation
  • Pollution
    • Nitrogen-input
  • Natural System modifications
    • Lack of fires
  • Natural biotic and abiotic processes (without catastrophes)
    • Species composition change (succession)

Habitat restoration potential

At least for generalist rock plants, the natural recovery of this habitat is possible and fast when it is not isolated from habitats of the same type. The return of specialized nesting birds after strong disturbances is less easy for example. The same applies to specialists plants of rock micro-habitats.

Trends in extent

Average current trend in quantity

Unknown Unknown
EU28 EU28+

Trends in quality

Average current trend in quality

Unknown Unknown
EU28 EU28+

Conservation and management needs

To preserve natural or semi natural disturbance regime, with a continuum of periodic rockfall and instability of the substrate the protection of some areas as nature reserve is recommended. Also management to stop the succession towards scrub and forest. Negative factors can be intensive grazing, hiking and trampling.

List of conservation and management needs

  • No measures
    • Measures needed, but not implemented


For each habitat a distribution map was produced from a wide variety of sources indicating known and potential occurrences of the habitat in 10x10 km grids within Europe. Occurrences in grid cells were given in two classes: actual distribution from relatively reliable sources (surveys, expert knowledge), and potential distribution based on models or less reliable indicators. Please download the fact sheet to see the map.

Geographic occurrence and trends

EU28 Present or presence uncertain Current area of habitat (Km2) Recent trend in quantity (last 50 years) Recent trend in quality (last 50 years)
Finland mainland Present 0.3 Stable Stable
Sweden Present Unknown Unknown Unknown
Northern Island Present Unknown Unknown Unknown
EU28 + Present or presence uncertain Current area of habitat (Km2) Recent trend in quantity (last 50 years) Recent trend in quality (last 50 years)
Norway Mainland Present Unknown Unknown Unknown

Extent of Occurrence, Area of Occupancy and habitat area

Extent of Occurrence (EOO) (Km2) Area of Occupancy (AOO) Current estimated Total Area Comment
EU28 1145050 47 unknown
EU28+ 49 unknown
AOO = the area occupied by a habitat measured in number of 10x10 km grid cells.
EOO = the area (km2) of the envelope around all occurrences of a habitat (calculated by a minimum convex polygon).

Characteristic species

Not available

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Other classifications

Not available
European Environment Agency (EEA)
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