EUNIS habitat classification 2017 > U - Inland habitats with no or little soil and mostly with sparse vegetation > U2 - Screes > U21 - Boreal and arctic siliceous scree and block field

Boreal and arctic siliceous scree and block field

Description (English)

Boreal and Arctic sparsely vegetated siliceous boulders, stones or gravel screes occurring over base-poor substrates that harbour acidophilous plant communities. They are of diverse origin, uneven distribution through the region and often subject to continuing natural disturbance through rock falls, freeze-thaw or coastal erosion and deposition. The vegetation typically consists of bryophytes and lichens with different growth forms dominating different microhabitats, e.g. small cushion-forming bryophytes and crustose and foliose lichens on the sides of boulders, and mat-forming bryophytes and fruticose lichens in the hollows between blocks. Where vascular plants find enough soil between blocks, they contribute a sparse cover.

Source: EUNIS habitat classification

Quick facts

EUNIS habitat type	code U21
Relation to	Resolution 4 habitat type (used for designation of Emerald sites)

Legal status

Relation to other habitat types mentioned in legal instruments

Legal text	Annex	Name in legal text	Code in legal text	Habitat type relationship	More information
Convention on the conservation of European wildlife and natural habitats	Revised Annex I of Resolution 4 (1996) of the Bern Convention on endangered natural habitats types using the EUNIS habitat classification (year of revision 2010)	Siliceous scree of the montane to snow levels (Androsacetalia alpinae and Galeopsietalia ladani)	8110	Narrower	https://wcd.coe.int/ViewDoc....ckColorLogged=FDC864 Resolution No. 4 (1996) of the Bern Convention lists endangered natural habitats requiring specific conservation measures [and the designation of Areas of Special Conservation Interest (ASCIs) forming the Emerald network]
Convention on the conservation of European wildlife and natural habitats	Revised Annex I of Resolution 4 (1996) of the Bern Convention on endangered natural habitats types using the EUNIS habitat classification (year of revision 2010)	Cold siliceous screes	H2.1	Same	https://wcd.coe.int/ViewDoc....ckColorLogged=FDC864 Resolution No. 4 (1996) of the Bern Convention lists endangered natural habitats requiring specific conservation measures [and the designation of Areas of Special Conservation Interest (ASCIs) forming the Emerald network]

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Indicator species

Diagnostic species

Constant species

Dominant species

Flowering Plants Calamagrostis lapponica

Flowering Plants Carex bigelowii

Flowering Plants Astragalus alpinus

Flowering Plants Viola biflora

Flowering Plants Gnaphalium supinum

Flowering Plants Sibbaldia procumbens

Flowering Plants Festuca ovina

Flowering Plants Carex lachenalii

Ferns Botrychium boreale

Flowering Plants Salix herbacea

Flowering Plants Solidago virgaurea

Flowering Plants Oxyria digyna

Flowering Plants Rhodiola rosea

Flowering Plants Saussurea alpina

Diagnostic species occur concentrated in the habitat in question, but are absent or rare in other habitats. They are good positive indicators of the habitat, but they do not need to occur in every location of the habitat.

Species scientific name	English common name	Species group
Calamagrostis lapponica		Flowering Plants
Carex bigelowii		Flowering Plants
Astragalus alpinus		Flowering Plants
Viola biflora		Flowering Plants
Gnaphalium supinum		Flowering Plants
Sibbaldia procumbens		Flowering Plants
Festuca ovina		Flowering Plants
Carex lachenalii		Flowering Plants
Botrychium boreale		Ferns
Salix herbacea		Flowering Plants
Solidago virgaurea		Flowering Plants
Oxyria digyna		Flowering Plants
Rhodiola rosea		Flowering Plants
Saussurea alpina		Flowering Plants

Flowering Plants Festuca ovina

Flowering Plants Viola biflora

Flowering Plants Solidago virgaurea

Flowering Plants Vaccinium vitis-idaea

Flowering Plants Carex bigelowii

Flowering Plants Anthoxanthum odoratum

Flowering Plants Avenella flexuosa

Flowering Plants Salix herbacea

Flowering Plants Gnaphalium supinum

Flowering Plants Calamagrostis lapponica

Flowering Plants Campanula rotundifolia

Flowering Plants Sibbaldia procumbens

Flowering Plants Saussurea alpina

Flowering Plants Juncus trifidus

Flowering Plants Trientalis europaea

Flowering Plants Oxyria digyna

Constant species occur frequently in the habitat, but they may include generalist species that are also frequent in other habitats.

Species scientific name	English common name	Species group
Festuca ovina		Flowering Plants
Viola biflora		Flowering Plants
Solidago virgaurea		Flowering Plants
Vaccinium vitis-idaea		Flowering Plants
Carex bigelowii		Flowering Plants
Anthoxanthum odoratum		Flowering Plants
Avenella flexuosa		Flowering Plants
Salix herbacea		Flowering Plants
Gnaphalium supinum		Flowering Plants
Calamagrostis lapponica		Flowering Plants
Campanula rotundifolia		Flowering Plants
Sibbaldia procumbens		Flowering Plants
Saussurea alpina		Flowering Plants
Juncus trifidus		Flowering Plants
Trientalis europaea		Flowering Plants
Oxyria digyna		Flowering Plants

Dominant species are those that often reach high cover in the habitat, thus determining the habitat physiognomy.

Species scientific name	English common name	Species group

Please note that a maximum of 20 species of each indicator category is shown.

Other classifications

Classification	Code	Habitat type name	Relationship type
EUNIS Habitat Classification 2007 (revised descriptions 2012)	H2.1	Cold siliceous screes	same
European Red List of Habitats	H2.1	Boreal and arctic siliceous scree and block field	same

For relation to plant communities (syntaxa), see Vegetation types

History

Classification	Code	Habitat type name	Relationship type
EUNIS Habitat Classification 200410	H2.1	Cold siliceous screes	same
EUNIS Habitat Classification 200308	H2.1	Cold siliceous screes	same
EUNIS Habitat Classification 200202	H2.1	Cold siliceous screes	same
EUNIS Habitat Classification 199910	H2.1	Boreal siliceous screes	same
EUNIS Habitat Classification 199811	H2.1	Boreal siliceous screes	same
EUNIS Habitat Classification 199712	H2.1	Boreo-alpine siliceous screes	same
Palaearctic Habitat Classification 199905	61.61	Boreal siliceous screes	same
Palaearctic Habitat Classification 1997	61.61	Boreal siliceous screes	same
Palaearctic Habitat Classification 1996	61.61		same
Palaearctic Habitat Classification 1993	61.61		same

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