Diversity and biogeographic patterns of the bryozoan fauna of the Faroe Islands

Abstract

ABSTRACTA total of 228 bryozoan species are recorded within the EEZ of the Faroe Islands, 74 of which are new to the area. Analysis of the distribution of the species among six sectors, each characterized by different environmental conditions, showed three faunal assemblages. Variation of the total Faroese bryozoan fauna and of the bryozoan fauna of most sectors, demonstrated significant negative relationships with depth. In general, analysis of the biogeographic composition showed a strong predominance of boreal over arctic species. However, with respect to faunas of each sector, the Norwegian Basin is characterized by a predominance of arctic species and may be regarded as a part of the Arctic Eurasian sub-region of the Arctic biogeographic region. Comparison of the bryozoan species of each sector with the bryozoan faunas of the other 12 areas in the North Atlantic and the neighbouring Arctic regions showed that only the Faroese shelf fauna has significant similarity with part of them, and thus can be regarded as part of the Scandinavian province of the Norwegian high-boreal sub-region of the Atlantic boreal region. Three sectors, the Faroese–Iceland Ridge, the Faroese–Shetland Channel and Norwegian Basin, belong to a transitional zone between the Atlantic Boreal and the Arctic biogeographic regions. The deep south-western sector forms a separate faunal cluster when compared with both the other sectors within the Faroese area and with the faunas of other large geographic areas, and may be regarded as a separate biogeographic zone of the Boreal Atlantic region due to its high proportion of specific species.