Habitat point records from 1977-79 SWBSS Grassholm, Skomer & Marloes Peninsula survey

Surveys of nearshore sublittoral ecosystems were carried out at Skomer in August 1977, Grassholm in June 1979 and on the Marloes Peninsula near Martins Haven in July 1979. The Skomer surveys were mainly a reconnaissance of the area whilst at Grassholm and Martins Haven, systematic surveys of the abundance of species in different habitats were carried out. The sites studied were subject to widely different regimes of exposure to water movement and included steep cliffs often extending into deep water, broken rock slopes, boulders and a variety of mixed sediments. A total of twenty-one sites were surveyed and the survey results are presented as an annotated list of 89 plant and 201 animal species with a description of each site, and summary of the communities present in different habitats. The survey results for Skomer and Martins Haven have been compared with the descriptions of the nine sublittoral habitats and communities defined for the whole coast of the area by Hunnam (1976). Although there are many similarities in the two sets of data, several of the habitats described here were either not encountered by Hunnam or their individual characteristics were lost in the generalised description of communities within a small number of habitat categories. The area described here included a wide variety of habitats and communities compared to most other locations of similar area in south-west Britain. Several locations were identified as of scientific interest. In addition, several species normally confined to the south or west coasts of the British Isles and abundant around Lundy were recorded but in very small amounts. It is recommended that future work related to conservation interests in the area should include studies of the west coast of Grassholm and The Smalls, and detailed descriptions of habitats and communities at key sites already identified in the region of Skomer. Some further basic survey to include previously undescribed habitats and communities and to provide a basis for mapping is also required in the region of Skomer.