Spinnen

An analysis of the spider community structure and the presence of specific species in the Flemish coastal dunes are presented. The analysis is based on data from more than 170 year-round pitfall samplings from the 1970s onwards. We were able to find indicator species for almost all identified habitats. The assemblages are structured by variation in vegetation structure [succession], atmospheric and soil humidity and the presence of both natural or anthropogenic disturbance. Specific and threatened species are particularly found in salt marshes, marram dunes, grey dunes and young sandy dune slacks. A detailed study on the species-area relationship of spiders in moss dominated dunes and short grasslands indicated that total species numbers do not increase as a function of the patch size. The total number of typical species is, however, higher in larger patches. These results indicate higher edge influences in small patches and the importance of microhabitat variation [which should be higher in large patches] or minimal population size for the presence of characteristic species in these habitat patches.