An Experimental Investigation into the Ecology of Some Maritime Cliff Species: I. Field Observations

Abstract

(1) Background information on the phytosociological, edaphic and climatic relationships of six maritime species is given as a basis from which to make an experimental study of factors influencing their distributions. (2) Crithmum maritimum, Spergularia rupicola and Inula crithmoides are members of the Crithmo-Spergularietum association of maritime crevices in southern Britain. (3) Ligusticum scoticum is a member of the equivalent northern Armeria maritimaGrimmia maritima association. Overlap of this association with the CrithmoSpergularietum occurs in south-west Scotland only. (4) Lavatera arborea is characteristically found in the Atriplici-Betetum association of bird cliffs, but also occurs in highly maritime rubbish tips, both in southern Britain. (5) Daucus carota ssp. gummifer is found in maritime grasslands and heaths in southern Britain. (6) Soil analysis suggests that five of the six species should be tolerant of high salinities, whilst Daucus should tolerate moderate salinities. Inula is found on soils with a high calcium content. (7) The maritime climate is characterized by a smaller temperature range and far fewer frosts than in inland areas, together with a very much higher frequency of gales. (8) It is suggested that the six maritime species studied may be restricted to sea cliffs, not because of a requirement for a saline environment, but because they are more tolerant of salinity than are competitors, whilst being sensitive to cold.