Activities listed are those which influence, or are likely to influence this habitat
and which are assessed in the UK marine SAC project review. The sensitivity rank may
require amendment in the light of new information becoming available.
| Sensitivity to: |
Human activity |
Rank |
Comments |
| Siltation |
Extraction: sand/gravel (aggregate dredging) |
Low |
The likelihood of damage due to sediment plumes in areas
adjacent to gravel extraction is unclear, as there is no knowledge of the effects of
differing particle size upon Sabellaria. However, it would be surprising if damage
was other than very localised given Sabellaria’s preference for turbid
waters. |
| Changes in temperature |
Climate change/global warming |
Low |
Owing to the sublittoral habitat occupied by Sabellaria
spinulosa it is not very sensitive to temperature change. |
| Synthetic compound contamination |
Waste: industrial effluent discharge |
Low |
Hoare & Hiscock (1974) investigated the distribution of
marine organisms around the outfall from a bromide extraction plant in North Wales. The
effluent has a pH of 4 and contained free halogens. Species richness and diversity was
markedly reduced within 150 m of the outfall, but Sabellaria was found closer to
the outfall than any other organism. |
| Changes in nutrient levels |
Waste: sewage discharge |
Not sensitive* |
Walker & Rees (1980) reported that in the discharge area
and down tide of the area Sabellaria spinulosa was present in greater densities and
diversities than elsewhere in the bay. |
| Abrasion |
Fishing: benthic trawling |
High |
Berhahn & Vorberg (1993) have suggested that Sabellaria
spinulosa is a good indicator of fishing intensity in the Wadden Sea. Subtidal Sabellaria
reefs are reported to have been lost due to physical damage in at least five areas. In the
Wadden Sea, Reisen & Reise (1982) reported that extensive subtidal Sabellaria
spinulosa reefs were lost from Lister Ley, island of Sylt, between 1924 and 1982. They
attributed the losses to destruction by "heavy gear" as populations were in the
way of shrimp trawling. Reise & Schubert (19870 reported similar losses from Norderau
area, and attributed them to similar causes. Trawling still occurs in these areas and as a
result Sabellaria has been replaced by Mytilus edulis and sand-dwelling amphipods in these
areas (Reise & Schubert 1987). Populations have also been destroyed in Morecambe Bay
(England) (Taylor 1993: Mistakidis 1956) |
| |
Extraction: sand/gravel (aggregate dredging) |
High |
In the short term Sabellaria spinulosa reefs would be
severely damaged by extensive aggregate dredging activities. The speed of recovery from
such damage is currently unknown. Compared to fishing impacts, gravel extraction is likely
to be more limited in extent, more controlled, and less likely to continue for very long
periods of time. So although direct damage would obviously be severe, recovery from
adjacent undamaged areas seems more likely. |
