Seasonality and Reproductive Phenology of Algae Inhabiting Littoral Pools in the Western Mediterranean

Abstract

Abstract. This paper reports on a one‐year investigation carried out in Cystoseira‐dominated littoral pools from the west coast of Italy.The seasonal occurrence of the algae and their reproductive characteristics are described. The importance of environmental factors and recruitment processes in determining algal distribution and abundance are also discussed.SummaryAlgal seasonality and reproductive phenology was studied in Cystoseira‐dominated tidepools from July 1989 to July 1990. Algae were collected monthly, sorted to species, and checked for reproductive structures. The data were analyzed by means of multivariate techniques (PCA and cluster analysis).Seasonal fluctuations were more evident for annual and ephemeral algae, with peaks in abundance during the summer, while perennial algae showed a slight decline in winter because of storms. Among the 66 taxa recorded, 26 algae were found to be fertile at least once during the study year. These species showed a considerable variation in the seasonal periodicity of reproduction.We suggest that the seasonal patterns of the assemblage were mainly regulated by physical factors, because herbivores were virtually absent in the investigated pools. Moreover, the periodicity of algal reproduction could also have an effect. Since the pool of propagules available to colonize newly disturbed areas changes through time according to the reproductive phenology of the algae and varies so widely, early successional sequences may be governed by the disturbance regime and propagule availability.