Phenology and small-scale distribution of some rhodomelacean red algae on a western Mediterranean rocky shore

Distribution and phenology of some filamentous species of Rhodomelaceae in the low littoral and shallow sublittoral zones of an exposed, western Medit erranean rocky shore were studied for I year. The spatial distribution of m any species shows a pronounced small-scale (metres or tens of metres) varia bility. Boergeseniella fruticulosa was most abundant in spring and fertile (tetrasporangia only) in spring and summer. Polysiphonia flocculosa was mos t abundant in spring and summer and reproductive throughout the year. Polys iphonia opaca was most abundant in summer and fertile in spring-summer. Max imal vegetative development and reproduction of Lophosiphonia cristata were observed in summer; conversely, Polysiphonia ceramiaeformis and Polysiphon ia subulata were best developed and mostly reproductive in winter and sprin g. Womersleyella setacea was the least abundant of the studied species and apparently reproduced only by vegetative growth and fragmentation. The repr oductive phenology of the species investigated is generally in agreement wi th reports for other Mediterranean regions. The life history traits of most species are typical of seaweeds in which environmental factors directly go vern the onset of the main activities of the organism by meeting the primar y physiological needs ('season responders').