LARGE-SCALE SPATIAL PATTERN OF THE MACROBENTHIC DIVERSITY IN THE EASTERN ENGLISH-CHANNEL

A description is provided of the large-scale spatial distribution of t he diversity of the benthic macrofauna in the eastern English Channel. Data from the oceanographic cruises of the RCP (Recherche Cooperative sur Programme) Benthos de la Manche Research Programme were obtained during the summers of 1971 to 1975. A total of 707 samples were analys ed. Diversity of each sample was measured by means of the species rich ness (i.e. the total number of species present), the Shannon-Weaver di versity index and Pielou's evenness index. Diversity values were plott ed for all 707 oceanographic stations in the area, following a smoothi ng procedure. Large-scale spatial trends of diversity of the benthic m acrofauna were analysed in relation to sediment and species assemblage distribution, but no spatial correlation was found between the two fa ctors. These results indicate that mechanisms affecting large-scale sp atial distribution of the diversity are different from those acting on a smaller scale. The role of the hydro-sedimentary processes acting a t the geographic scale of the eastern English Channel as presumptive c auses of this large-scale pattern of the macrobenthic diversity is dis cussed.