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)

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Indicator species

Diagnostic species
Constant species
Dominant species
Flowering Plants Trisetum spicatum
Flowering Plants Calamagrostis lapponica
Flowering Plants Antennaria alpina
Flowering Plants Carex bigelowii
Flowering Plants Hieracium lachenalii
Flowering Plants Astragalus alpinus
Flowering Plants Agrostis mertensii
Flowering Plants Viola biflora
Flowering Plants Cassiope hypnoides
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
Trisetum spicatum Flowering Plants
Calamagrostis lapponica Flowering Plants
Antennaria alpina Flowering Plants
Carex bigelowii Flowering Plants
Hieracium lachenalii Flowering Plants
Astragalus alpinus Flowering Plants
Agrostis mertensii Flowering Plants
Viola biflora Flowering Plants
Cassiope hypnoides 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 Hieracium lachenalii
Flowering Plants Avenella flexuosa
Flowering Plants Salix herbacea
Flowering Plants Gnaphalium supinum
Flowering Plants Calamagrostis lapponica
Flowering Plants Trisetum spicatum
Flowering Plants Campanula rotundifolia
Flowering Plants Antennaria alpina
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
Hieracium lachenalii Flowering Plants
Avenella flexuosa Flowering Plants
Salix herbacea Flowering Plants
Gnaphalium supinum Flowering Plants
Calamagrostis lapponica Flowering Plants
Trisetum spicatum Flowering Plants
Campanula rotundifolia Flowering Plants
Antennaria alpina 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

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 Comment
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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