The zonation and ecology of a sand-dune spider community

Despite being a harsh environment, sand dunes are rich in invertebrates, with about 30% (188 species) of the British spider fauna represented (Duffey, 1968), and 53 species being strongly associated with coasts (Ratcliffe, 1977). Arachnologists have examined spider communities in relation to the seral succession of plant communities on sand dunes (e.g. Lowrie, 1948; Barnes, 1953; Perttula, 1984). Several factors influence the spider communities found, including plant diversity, cover, life form and distribution (Duffey, 1968; Uetz, 1991), as well as temperature, humidity and wind velocity (Almquist, 1973a,b). On the south Lancashire sand dunes, Mackie (1967) and Felton (1993) found that, although the majority of spiders collected are common throughout Britain, two notably rare coastal specialists occur. These are Attulus saltator (Simon) (Salticidae) and Argenna patula (Simon) (Dictynidae) which inhabit open sandy places and the strandline (Felton, 1993). The aim of this paper is to explore the relationships between the structure and diversity of the four major plant zones and the spider communities which are found in each of those areas.