Description of biotope or habitat type
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Yellow and grey lichens on supralittoral rock
Physical habitat description
| Salinity | Full (30-35 ppt), Variable (18-35 ppt) |
|---|---|
| Wave exposure | Very exposed, Exposed, Moderately exposed, Sheltered, Very sheltered |
| Tidal streams | |
| Substratum | Bedrock; stable boulders |
| Zone | Supralittoral |
| Depth Band | |
| Other Features |
Download comparative physical and biological data. The comparative tables enable a rapid comparison of the species composition and principal physical characteristics between a given set of biotopes.
- Records used to define the biotope (core records)
- Other records assigned to this biotope, marked as 'certain'
- Other records assigned to this biotope, marked as 'uncertain'
Point data based on records in the UK Marine Recorder Snapshot.
Description
Vertical to gently sloping bedrock and stable boulders in the supralittoral (or splash zone) of the majority of rocky shores are typically characterised by a diverse maritime community of yellow and grey lichens, such as Xanthoria parietina, Caloplaca marina, Tephromela atra var. atra and Ramalina spp. The black lichen Verrucaria maura is also present, but usually in lower abundance than in the littoral fringe zone. In wave exposed conditions, where the effects of sea-spray extend further up the shore, the lichens generally form a wide and distinct band. This band then becomes less distinct as wave exposure decreases, and in sheltered locations, cobbles and pebbles may also support the biotope. Pools, damp pits and crevices in the rock are occasionally occupied by winkles such as Littorina saxatilis and halacarid mites may also be present.
Situation
This biotope is usually found at the top of the shore, immediately above a zone of the black lichen V. maura (Ver.Ver; Ver.B). Above the band of YG, and occasionally in crevices in the rock alongside the lichens, terrestrial plants such as the thrift Armeria maritima and other angiosperms often occur. In sheltered areas the transition from YG to Ver.Ver is often indistinct and a mixed zone of YG and Ver.Ver may occur. In estuaries, this biotope is often restricted to artificial substrata such as sea defences.
Temporal variation
Unknown.
Characterising species
| Taxon | Relative importance of taxon for defining this community (%) | Typical abundance - SACFOR scale | % of core records where taxon was recorded |
|---|---|---|---|
| Xanthoria parietina | 27 | Frequent | 61-80% |
| Verrucaria maura | 21 | Frequent | 61-80% |
| Grey lichens | 17 | Frequent | 41-60% |
| Caloplaca marina | 12 | Occasional | 41-60% |
| Ramalina | 6 | Frequent | 41-60% |
| Tephromela atra var. atra | 4 | Frequent | 21-40% |
| Caloplaca thallincola | 4 | Occasional | 21-40% |
Similar biotopes or habitat types
LR.FLR.Lic.Pra
Occurs in similar physical conditions, but this biotope is usually confined to a nitrate enriched environment such as below bird rocks. LR.FLR.Lic.Pra has a characteristic high abundance of the small green seaweed Prasiola stipitata, which overgrows the yellow and grey lichens.
LR.FLR.Lic.Ver.Ver
Occurs in similar physical conditions but usually below the LR.FLR.Lic.YG biotope. V. maura and the winkle L. saxatilis are present in a higher abundance and dominates this biotope. See also "Situation" above.Classification history of this biotope or habitat type
| Classification version | Code |
|---|---|
| 1996 (6.95) | SUR.YG |
Photos
