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Marine Habitat Classification


Description of biotope or habitat type

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   Verrucaria maura on very exposed to very sheltered upper littoral fringe rock


Habitat (physical) 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; stable cobbles
Zone Littoral fringe - upper
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.

Distribution of habitat LR.FLR.Lic.Ver.Ver <I>Verrucaria maura</I> on very exposed to very sheltered upper littoral fringe rock

  • 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

Upper littoral fringe bedrock, boulders and stable cobbles on very exposed to very sheltered shores which have a blanket covering of the black lichen Verrucaria maura. The winkle Littorina saxatilis is often present. Due to the nature of this biotope it is species poor, but occasionally a range of species may be present in low abundance. These species include the yellow lichen Caloplaca marina and the winkle Melarhaphe neritoides, the barnacles Chthamalus montagui and Semibalanus balanoides or the ephemeral seaweeds Porphyra umbilicalis and Enteromorpha spp. can be present in low abundance (see Ver.B). If one or more of these species is present compare with Ver.B. On northern shores Littorina saxatilis var. rudis can dominate along with the occasional presence of the lichens Verrucaria mucosa and Xanthoria parietina. V. maura can be found overlying stable mud in N. Ireland sea loughs.

Situation

The black lichen zone is normally found below the yellow and grey lichen zone (YG). In very sheltered areas there is not always a clear transition from one zone to the next and a mixed zone of YG and Ver.Ver is common. The wrack Pelvetia canaliculata can occur on these more sheltered shores. With increasing wave exposure the two lichen zones become wider and more distinct, and the Ver.Ver gives way to a lichen and barnacle dominated community (Ver.B) in the lower littoral fringe.

Temporal variation

In areas with nitrate enrichment V. maura can be overgrown by the small green seaweed Prasiola stipitata (Pra) which reaches its maximum abundance during the winter months. It generally dies out during the summer in southern Britain, reverting the biotope to Ver.Ver.

Characterising Species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Littorina saxatilis 7 Frequent 41-60 %
Verrucaria maura 87 Abundant 81-100 %

Similar biotopes

LR.FLR.Lic.YG
Occurs in similar physical conditions, but usually above the Ver.Ver biotope. Yellow and grey lichens such as Xanthoria parietina, C. marina and Lecanora atra dominate this biotope, and V. maura is less common.

LR.FLR.Lic.Ver.B
Occurs in similar physical conditions (absent on sheltered shores) below the Ver.Ver biotope. The fauna is more diverse and barnacles C. montagui or S. balanoides are present. Ephemeral seaweeds such as the red seaweed P. umbilicalis and the green seaweed Enteromorpha intestinalis can be present in high abundance.

Biotope history

Classification Habitat code
6.95 LRK.VER.VER

Photos

LR.FLR.LIC.Ver.Ver Verrucaria maura on very exposed to very sheltered upper littoral fringe rock, E shore, Eilean nan Eildean, Loch Sunart. Mark Davies © JNCC
LR.FLR.LIC.Ver.Ver Verrucaria maura on very exposed to very sheltered upper littoral fringe rock, E shore, Eilean nan Eildean, Loch Sunart. Mark Davies © JNCC
LR.FLR.LIC.Ver.Ver Verrucaria maura on very exposed to very sheltered upper littoral fringe rock, Entrance to Sailean Mor, Oronsay, Loch Sunart. ANON © JNCC
LR.FLR.LIC.Ver.Ver Verrucaria maura on very exposed to very sheltered upper littoral fringe rock, Entrance to Sailean Mor, Oronsay, Loch Sunart. ANON © JNCC
LR.FLR.LIC.Ver.Ver Verrucaria maura on very exposed to very sheltered upper littoral fringe rock, Broadhaven, Dunbar. Jon Davies © JNCC
LR.FLR.LIC.Ver.Ver Verrucaria maura on very exposed to very sheltered upper littoral fringe rock, Broadhaven, Dunbar. Jon Davies © JNCC

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