Community Structure, Succession, and Production of Seaweeds Associated wlth Mussel-Rafts in the Ria de Arosa, N. W. Spain

Abstract

Spatial and temporal patterns of community structure, succession, and production of seaweeds associated with mussel-rafts in the Ria de Arosa, Spain, were studied at 4 stations during 1 y (1978-1979). Community structure changed due to seasonal changes in abiotic factors (light, temperature, etc.) and an algal succession on new mussel rafts from an initial ephemeral flora (e.g. Ulva rigida, Enteromorpha spp., Polysiphonia spp.) during fall and winter to a kelp-dominated flora in the summer. During summer, Laminaria saccharina dominated the innermost estuarine station, whereas Saccorhiza polyschides dominated the 3 outer stations. Because of the succession to a kelp-dominated community, species diversity and evenness decreased over time, whereas species richness generally increased.