Zoobenthos associated with the invasive red alga Womersleyella setacea (Rhodomelacea) in the northern Aegean Sea

Abstract

The spatial and temporal structure of the zoobenthos associated with the invasive red alga Womersleyella setacea was studied in the northern Aegean Sea, Greece. Five replicate quadrats (20×20 cm) were collected, seasonally from July 1997 to August 1998, by SCUBA diving at four sites and two depth levels (15 and 30 m) in the Chalkidiki peninsula. We collected 23,090 specimens representing 278 animal species. Multivariate analysis showed mainly spatial differences in community structure, while the temporal ones were minimal. The ordination of sites showed a clear zonation pattern according to the different algal forms that cover the rocky substrate, with inclination the only environmental factor involved. The epifauna associated with the invasive alga was differently structured compared with three native seaweeds, showing increased species richness and abundance. The filamentous alga W. setacea was dominant in all seasons and depth levels, creating a stable habitat that contributed to the loss of seasonality in zoobenthic community structure.