Marine Coastal Zonation in Southern Australia in Relation to a General Scheme of Classification

Abstract

Marine ecological studies on coastal regions have been greatly advanced in recent years by the publications of T. A. Stephenson and his co-workers on the South African intertidal zone. In three papers Stephenson (1939, 1944 and 1947) described the zonation and distribution of marine animals and algae over nearly 2000 miles of South African coast. In a later paper T. A. & A. Stephenson (1949) have proposed a general scheme for the zonation of organisms between tide-marks (including the zones above and below the actual intertidal zone), which they believe will apply to rocky coasts generally. This scheme was founded on studies of coasts in England, parts of the Indian Ocean, on both Atlantic and Pacific coasts of North America and on the Great Barrier Reef, as well as on their South African survey. Stephenson has examined more coastal regions than any other worker in marine ecology, and consequently is in an excellent position to put forward a generalized scheme. However, while aware that we have seen a comparatively small range of coasts, it appears to us that the Stephensons' scheme does not apply satisfactorily to Southern Australian coasts, and also that certain objections can be raised to their terminology. This paper aims at setting out our criticisms of their scheme, and proposing a modified scheme which we have found satisfactory for Southern Australian coasts. Our proposed scheme appears, from published descriptions of coasts elsewhere in the world, to be of general application. The scheme does not involve any fundamentally new terms. It is, rather, an integration of terms and zones, used by other marine ecologists, which seem most suitable to Australian conditions. With much of the Stephensons' paper, however, we are in full agreement. Their discussion of 'standard' zonation, and variations from this, hold for Southern Australian rocky coasts, and while balanoid and littorinid zones are features of most of our coasts, we agree that these terms cannot be used in a general scheme. The Stephensons' scheme, from the title of their 1949 paper, is intended to apply to rocky coasts. A general scheme of coastal zonation should be applicable to any type of coast (whether it be a gently shelving mud flat with a sandy beach or mangroves at the rear, the many variations of rocky coasts, or any other kind). Whilst schemes developed for rocky coasts will probably be applicable to other types of coast, this may not always be so. In particular, different species may need to be used as indicator species.