An Intertidal Survey of the Biotopes of Rocky Scars in the Drigg Coast, European Marine Site.
Abstract
The objectives of this report are to map the extent of the rocky skears in the Esk estuary, Mite Estuary, Irt Estuary and the Channel, and to provide detailed descriptions of the biotopes they support. Habitat diversity on rocky skears is generally restricted, leading to a limited range of species being recorded. This is particularly evident on the rocky biotopes of the Drigg Coast. Within the estuaries, species diversity was generally affected by variable and reduced salinities, lack of stability, or less frequently siltation; while in the Esk Channel (from the confluence of the Esk, Mite and Irt), species diversity was reduced by mobile substrata and sand scour. Even in those areas where the substrata had been stabilised by Mytilus edulis or Sabellaria alveolata, there were relatively impoverished communities. All the habitats and communities surveyed (with the exception of Mite Bridge), are believed to be natural and representative of the northwest. The diversity of habitats and communities is very low. Most of the communities are surviving in highly stressed and variable environments and are therefore unlikely to be fragile. The low species richness generally results in a low sensitivity to disturbance and environmental change. The one exception to this may be the Sabellaria alveolata reef which may be considered fragile and of limited extent nationally.