Screes
Accumulations of boulders, stones, rock fragments, pebbles, gravels or finer material, of non-aeolian depositional origin, unvegetated, occupied by lichens or mosses, or colonized by sparse herbs or shrubs. Included are screes and scree slopes produced by slope processes, moraines and drumlins originating from glacial deposition, sandar, eskers and kames resulting from fluvio-glacial deposition, block slopes, block streams and block fields constructed by periglacial depositional processes of downslope mass movement, ancient beach deposits constituted by former coastal constructional processes. Deposits originating from aeolian depositional processes (dunes) or from eruptive volcanic activity are not included; they are included in H5 and H6 respectively. High mountain, boreal and mediterranean unstable screes are colonized by highly specialised plant communities. They or their constituting species may also inhabit moraines and other depositional debris accumulations in the same areas. A very few communities form in lowland areas elsewhere.
Important species scientific name | Corresponding species comments |
---|---|
Dryopteris fragrans (L.) Schott | Annex II species - habitat relation; source Unit of Vegetation Science, Lancaster, 2000 |
Braya linearis Rouy | Annex II species - habitat relation; source Unit of Vegetation Science, Lancaster, 2000 |
Arenaria ciliata ssp. ciliata L. | Annex II species - habitat relation; source Unit of Vegetation Science, Lancaster, 2000 |
Arenaria humifusa Wahlenb. | Annex II species - habitat relation; source Unit of Vegetation Science, Lancaster, 2000 |
EUNIS Code | Type Name | Name |
---|---|---|
H2.5 | Acid siliceous screes of warm exposures | Acid siliceous screes of warm exposures |
H2.1 | Cold siliceous screes | Cold siliceous screes |
H2.2 | Cold limestone screes | Cold limestone screes |
H2.3 | Temperate-montane acid siliceous screes | Temperate-montane acid siliceous screes |
H2.4 | Temperate-montane calcareous and ultra-basic screes | Temperate-montane calcareous and ultra-basic screes |
H2.6 | Calcareous and ultra-basic screes of warm exposures | Calcareous and ultra-basic screes of warm exposures |