Response to Wave Exposure by Littoral Species in the Faroe Islands Hvussu djórasløg í føroyskum firðum laga seg eftir aldubrotum



Published Jan 1, 1999
Grethe Bruntse Tor Eiliv Lein Ruth Nielsen Karl Gunnarsson


This investigation describes the rocky shore communities in the littoral zone of the Faroe Islands and their response to wave exposure. We utilised the Expon software and its reciprocal algorithm to develop response functions (polynomials) to wave exposure for species based on the abundance of 23 dominant species at 146 stations. Among the seven environmental factors
analysed, wave exposure explained most of the variance in the data set according to a preliminary correspondence analysis (CCA). A significant response to wave exposure was obtained for Aglaothamnion sepositum, Alaria esculenta, Corallina officinalis, Fucus distichus ssp. anceps, Himanthalia elongata, Mastocarpus stellatus, Polysiphonia stricta and Porphyra umbilicalis, predominantly found on exposed shores; for Ascophyllum nodosum, Cladophora rupestris, Pelvetia canaliculata,
Verrucaria mucosa, Littorina obtusata and Nucella lapillus, predominantly found on sheltered shores; and Semibalanus balanoides, with the greatest abundance on moderately exposed shores. A biological exposure scale was developed for the area based on the response curves for these 15 species. The scale is valid for rocky shores in the Faroe Islands with mean tidal amplitude larger than 0.40 m, and can be used to account for the distribution of dominant and frequently occurring species in the littoral zone. This is supplemented with diagrams illustrating the vertical distribution and abundance of species at localities selected to represent different wave exposure. Our studies confirm the descriptions of the distribution of littoral organisms in earlier works about the Faroe Islands. Compared to the British Isles and the south-west coast of Norway, the most striking
differences are fhe abundant growth of Laminaria digitata and Alaria esculenta on sheltered shores, the lack of dense populations of Fucus serratus and the frequent occurrence of many species over the whole exposure range.

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Natural Sciences