Epiphytic patterns of macroalgal assemblages on Cystoseira species (Fucales, Phaeophyta) in the east coast of Attica (Aegean Sea, Greece)

Abstract

Epiphytic macroalgal assemblages growing on Cystoseira species were examined at typical oligotrophic and eutrophic sites of the east coast of Attica (Aegean Sea, Greece) from November 1995 to September 1996. The epiphytic patterns of C. spinosa Sauvageau thriving in the oligotrophic area of Dikastika and of C. compressa (Esper) Gerloff & Nizzamudin growing in the eutrophic environment of Avlida, were compared through a cross-transplantation experiment. Seasonality effects on epiphytic assemblages were observed. The species composition was exclusive for each locality, reflecting differences in the trophic status of the two sites. No specific pattern of epiphytes' distribution was found on the hosts. The prolific epiphytic growth in the oligotrophic site resulted in a reduction of the photosynthetic tissue of both hosts (C. spinosa and the transplanted C. compressa) and the survivorship of host plants was not negatively affected by the physical drag caused by the high epiphyte densities. Cystoseira spinosa survived in oligotrophic conditions despite its heavy epiphytic load. C. compressa was also able to cope with the adverse epiphytic influence in the eutrophic conditions of Avlida; although being perennial, it sheds parts of its stipe and branches before the resting period and sprouts prior to other algae at the beginning of spring.