Consistency of faunal and floral assemblages within temperate subtidal rocky reef habitats

Habitats defined by various biological and environmental variables are increasingly assumed to be surrogates for biodiversity. This study tested this assumption for temperate subtidal rocky reefs off south-eastern Australia by investigating the consistency of floral and faunal macrobenthic assemblages within habitats defined by dominant vegetation, substratum lithology, depth, wave exposure and region. Taxonomic groups included seagrasses, rhodophytes, chlorophytes, phaeophytes, hydroids, bryozoans, molluscs, polychaetes, pycnogonids and echinoderms. The results from multivariate statistical analyses indicated that, although variation between replicate samples is high, habitats as defined by dominant vegetation and, to a lesser extent, region supported consistent floral and faunal assemblages. The patterns did not emphasize a broad-scale biogeographic gradient, but rather the environmental heterogeneity of the coastline at scales of 10–100 km.