Impact of ray feeding disturbances on sandflat macrobenthos: do communities dominated by polychaetes or shellfish respond differently?

Abstract

Myliobatis tenuicaudatus pits rapidly infilled with sediment of similar grain size to that of the surrounding sandflat. Organic carbon content only became elevated in the pits in the polychaete dominated community. Sediment within an area of 700-800 m2 at either site would be turned about every 70 d. Rapid recolonization of pits by macrofauna occurred in both communities, although bivalves tended to recolonize more rapidly than polychaetes. An epibenthic crustacean was the only species to indicate possible preferential exploitation of pits. The importance of passive transport of adults into pits is stressed. The tube-mat forming polychaete Boccardia syrtis, dominant at one site, was the only common species which did not colonize pits in the same proportion to that found in the sediment adjacent to pits. Rays may tend to smooth out distribution patterns, particularly those of long-lived infauna, and play a role in maintaining dominance patterns in both polychaete and bivalve communities. -from Authors