The Influence of Rocky Reefs on Structure of Benthic Macrofauna in Nearby Soft-sediments

Influences of rocky reefs on composition and abundances of species in assemblages of macrofauna in nearby subtidal, soft-sediments were examined by sampling at three distances from four rocky reefs, three natural and one man-made, in Botany Bay, NSW, Australia. There was significant spatial variation in structure of assemblages between transects and among reefs. The proportion of coarse material in sediments was generally larger close to, than far from, reefs. Assemblages sampled close to reefs were generally different in structure from those sampled away from rocky reefs. In multivariate analyses, assemblages close to reefs were spatially more variable than were those far from reefs. Analyses demonstrated that there were more species close to, than far from, the reefs; polychaetes of the family Syllidae were more abundant far from, than near to, rocky reefs. Artificial and natural rocky reefs influenced nearby benthic assemblages in sediments and various models are discussed to explain the patterns detected, especially those concerning predation and characteristics of the sediments.