A General Account of the Intertidal Ecology of South Australian Coasts

Abstract

An account is given of the environmental features. the intertidal ecology. and the biogeographical relationships of the coast of the State of South Australia .

The central and western coasts of South Australia are similar ecologically in comparable areas . In the supralittoral Melaraphe unifasciata (Gray) is dominant (except where conditions are very calm) and at high levels on very exposed coasts Calothrix fasciculata C. Agardh is found. The littoral zone where the coast is most exposed consists of barnacles-Chamaesipho in the upper littoral, Catophragmus in the mid littoral, and Balanus in the lower littoral-but where the coast is more sheltered it consists of molluscs in the upper and mid littoral and algae (Corallina, Gelidium, or Hormosira) in the lower littoral. In the upper sublittoral fucoid algae or in calm regions marine angiosperms are dominant. The south-east coast, however, differs in some respects from the central and west coasts. The number of barnacles found in the littoral zone is much reduced and the giant brown algae, Durvillea potatorum Areschoug and Macrocystis angustifolia Bory, are dominant in the upper sublittoral. This is associated with slightly lower sea temperatures.

Sheltered coasts are more prominent in South Australia than in the eastern States of Australia. These include the shores of Spencer and St. Vincent Gulfs, the northern shores of Kangaroo I., and a number of scattered bays.

The similarities between the coasts of South Australia and Victoria (Bennett and Pope 1953) are greater than the differences. Consequently the proposal of Bennett and Pope to recognize the Victorian and Tasmanian coasts as the Maugean Biogeographical Provinoe and the South Australian and the south-west Western Australian coasts as the Flindersian Province appears to be unjustified. It is suggested that the Naugean is best regarded as a subprovince with the Flindersian. The latter includes most of the coast of southern Australia.

Considerable differences are noticeable between the organisms which inhabit the rocky coast of South Australia and the south coast of Western Australia. The available evidence indicates that a transition from the Flindersian to the tropical Dampierian Province occurs along the south and west coasts of Western Australia. The terms "Indo-Australian Province" and "Baudinian Province" have been proposed by previous authors to describe this transitional region.

The Flindersian Province appears to be intermediate between cold-temperate and warm-temperate regions, becoming distinctly cool-temperate in Tasmania. It is relatively distinct from the warm-temperate Peronian Province of the coast of New South Wales.