Infaunal Polychaetes of a Rocky Intertidal Surfgrass Bed in Southern California

Polychaetes in the sediment-laden rhizome mat of a surfgrass (Phyllospadix scouleri and P. taylori) bed at Bluff Cove in southern California were sampled quarterly during 1980. Polychaetes were numerically dominant and their diversity and density exceeded those of other rocky intertidal habitats in California. Their species composition was similar to a Corallina-Gelidium rocky intertidal habitat, whereas their feeding/motility guilds resembled soft-bottom communities. The dominant feeding modes of polychaetes were deposit feeders and combination filter/deposit feeders, reflecting the importance of sediment accumulation to the assemblage. Cluster analysis of the samples revealed groupings based on changes in both individual polychaete species abundance and total density. The analysis indicated the presence of both spatial and temporal variations in the community structure of the polychaetes within the surfgrass bed.