Studies on the biosystematics and ecology of the Epilithic Crustose Corallinaceae of the British Isles

Abstract

The present study is part of a biosystematic-ecological investigation of the crustose corallines of the North Atlantic begun in 1960; it will be incorporated in abbreviated form into an extensive monographic treatment covering the entire North Atlantic region, planned for publication later in the present decade. In this paper, we present new data for the British Isles and discuss the relationship of the British coralline flora to that of the northern North Atlantic as a whole. Epilithic species occurring from the British Isles northward, in the eastern North Atlantic, are treated from a biosystematic point of view. Ecologically, the British flora is examined in detail with reference to previous publications by the first author on Norway (Adey, 1971), Iceland (Adey, 1968) and the western North Atlantic (Adey, 1966c). In the course of this investigation, material was also collected from French and Spanish coasts. These collections have been compared to the British flora, and tentative conclusions are discussed. However, until the Mediterranean and W. African coasts can be examined in detail to provide an equivalent frame of reference, the French and Spanish work cannot be considered complete. The focal point of this paper is the epilithic coralline flora. Bottom coverages of maerl or rhodolith (see Adey & Macintyre, 1973) apparently require a somewhat different quantitative approach from that used in rocky areas.