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) |
Summary
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
Threat status
Synthesis of Red List assessment
EU | |
Red List Category | Red List Criteria |
Data Deficient | - |
Europe | |
Red List Category | Red List Criteria |
Data Deficient | - |
Confidence in the assessment
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
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
List of conservation and management needs
- No measures
- Measures needed, but not implemented
Distribution
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 |
EOO = the area (km2) of the envelope around all occurrences of a habitat (calculated by a minimum convex polygon).
Characteristic species
Species scientific name | English common name | Species group |
---|---|---|
Equisetum scirpoides | Ferns | |
Gymnocarpium robertianum | Ferns | |
Woodsia alpina | Ferns | |
Arabis alpina | Flowering Plants | |
Arenaria humifusa | Flowering Plants | |
Artemisia norvegica | Flowering Plants | |
Braya linearis | Flowering Plants | |
Campanula rotundifolia | Flowering Plants | |
Cardaminopsis petraea | Flowering Plants | |
Carex capillaris | Flowering Plants | |
Cerastium alpinum | Flowering Plants | |
Draba fladnizensis | Flowering Plants | |
Dryas octopetala | Flowering Plants | |
Elymus macrourus | Flowering Plants | |
Luzula arcuata | Flowering Plants | |
Minuartia rubella | Flowering Plants | |
Oxytropis lapponica | Flowering Plants | |
Papaver laestadianum | Flowering Plants | |
Papaver radicatum | Flowering Plants | |
Papaver relictum | Flowering Plants | |
Pinguicula alpina | Flowering Plants | |
Poa alpina | Flowering Plants | |
Potentilla nivea | Flowering Plants | |
Roegneria borealis | Flowering Plants | |
Salix reticulata | Flowering Plants | |
Saxifraga aizoides | Flowering Plants | |
Silene acaulis | Flowering Plants | |
Thalictrum alpinum | Flowering Plants | |
Tofieldia pusilla | Flowering Plants |