Sabellaria reefs on moderate energy Atlantic circalittoral rock

This habitat occurs on moderately wave-exposed, circalittoral bedrock, boulders and cobbles subject to moderately strong tidal streams and is characterised by dense crusts on the upper faces of the hard surfaces formed by the sandy tubes of the polychaete worm Sabellaria spinulosa. In some cases the S.spinulosa may completely cover the rock, binding gravel and pebbles together. A diverse fauna may be found attached to and sometimes obscuring the crust, often reflecting the character of surrounding biotopes. There is usually no significant raised reef area.

Indicators of quality:

The condition of S. spinulosa reefs can be judged in different ways. For instance: the areal extent of the reef, its spatial patchiness, temporal stability, or number of associated species. Categorisation of condition may also consider a combination of these parameters. At present there is no consensus of approach or accepted yardstick against which to compare condition of individual reefs. Further to this, evidence suggests that S. spinulosa reefs may repeatedly develop and decline in a regular succession, through resettlement and demise of successive generations. An apparent deterioration in condition may therefore be natural and not necessarily reflective of an anthropogenic impact. The apparently ephemeral nature of S. spinulosa reefs is such that the condition of S. spinulosa reef habitat should be considered at a wider scale than individual reefs.

Synthesis of Red List assessment

Confidence in the assessment

Pressures and threats