Solway Firth SAC Rocky Scar Ground Community Condition Monitoring 2014.
Abstract
This report presents the results of a study to monitor and assess the extent and condition of the intertidal rocky scars sub-feature on the English side of the Solway Firth SAC. A two phased survey of the rocky scar ground communities was undertaken by Ecospan Environmental Ltd during two periods in June 2014. A total of 12 intertidal rocky scar ground habitat types were recorded and mapped. The most substantial areas of scar ground were found in the most southwestern extent of the SAC on the shores between Mawbray and Silloth. There, the majority of the intertidal scars were on the mid-shore tidal height where mussel beds dominated. The Sabellaria alveolata reefs were most extensive at the south-western boundary of the SAC off the coast at Mawbray where the honeycombe structures solely dominated a large proportion of the lower shore. On the upper shore in the lower estuary, much smaller, narrow scars either characterised by Ulva spp. or communities of barnacles and Littorina spp. were found. The non-native invasive barnacle species Austrominius modestus was recorded at 24 of the 35 transects that were sampled; through rarely at greater than 5% cover. The most notable activity observed was bait digging within the mussels beds. This activity has the potential to result in a loss in extent of the characteristic biotope which is a breach of the conservation objectives for the rocky scar ground sub-feature.