Chrysophyceae on vertical upper littoral fringe soft rock
Marine natural heritage importance
EC Habitats Directive
|Habitat Directive feature (Annex 1)
Large shallow inlets and bays
The algal communities characteristic of this biotope are not subject to exploitation. However, chalk cliff algal communities and this biotope are considered rare in the UK. Their rarity may be attributable to the scarcity of their habitat (see ecology and sensitivity) as a result of coastal defence works.
Urban and industrial development in the south east UK, resulted in a need for coastal defence works to stabilise cliffs and reduce coastal erosion. The construction of sea walls at the base of cliffs cuts off caves and tunnels from the inundation by the sea and prevents sea wash or spray reaching the cliff face. The cliff face may also be scarped and straightened to reduce falls and gullies torn down, resulting in loss of substratum (Fowler & Tittley, 1993). The resultant sea walls do not support the 'Chrysophyceae' algal communities, although limestone and brick structures support similar communities but with a reduced range of chalk species and communities (Tittley & Shaw, 1980; Fowler & Tittley, 1993). Tittley et al. (1998) surveyed chalk cliffs throughout England and revealed that 56% of coastal chalk in Kent and 33% in Sussex had been modified by coastal defence and other works. On the Isle of Thanet this increased to 74% and had resulted in the loss of a wide range of micro-habitats on the upper shore and the removal of splash-zone communities. Elsewhere in England, coastal chalk remains in a largely natural state (Anon, 1999e, Tittley et al., 1998).
Fowler & Tittley (1993) noted that the brown algae Kuetzingiella holmesii, characteristic of cave communities and Pleurocladia lacustris had not been re-recorded since the 1930s.
Chalk cliff communities are included in the Flamborough Head, Thanet Coast, South Wight and Rathlin Island, and South Wight Maritime candidate SACs (Anon, 1999e).
This review can be cited as follows:
Chrysophyceae on vertical upper littoral fringe soft rock.
Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line].
Plymouth: Marine Biological Association of the United Kingdom.
Available from: <http://www.marlin.ac.uk/habitatimportance.php?habitatid=121&code=2004>