Australia State of the Environment Report 2001 (Theme Report)
Australian State of the Environment Committee, Authors
Published by CSIRO on behalf of the Department of the Environment and Heritage, 2001
ISBN 0 643 06751 5
Beaches and dunes [CO Indicator 2.4]
Beaches and dunes are the sandy beaches of the open coast and the gulfs and bays, together with their associated foredune systems, including both windward and leeward slopes.
Beaches and dunes are among the best-known coastal habitats because of the relative ease of access and the high use they receive. They are also sites of significance to Indigenous people, not only for food collection but also as living places with strong cultural associations.
Dunes and sandy beaches account for over 50% of Australia's coastline and are places of great dynamism. Sand migrates along the coastline under the influence of waves, currents and wind and, according to conditions, sand may accumulate or erode at any given place along the coast. In South Australia, New South Wales and on the Gold Coast, beach erosion is a major problem (see Erosion of beaches and dunes).
Vegetation plays an important role in stabilising sand dunes to buffer the coast against periods of erosion. A recent survey (Sinclair Knight Merz 1998) indicates that dune vegetation has the lowest profile in our knowledge of coastal vegetation, and very few data sets were identified. One of the most detailed was a dune vegetation survey in New South Wales some 10 years ago.
Dunes, beaches and similar foreshores constitute important breeding habitat for a number of animals, including (in southern states) the Little Penguin, pelicans, gulls, terns, and (in the tropics) turtles. The beaches of remote islands and shores are also used extensively by birds and turtles for nest-building, and in many places birds use such beaches for feeding and roosting.
Beach fauna is varied and includes smaller animals such as crabs and other crustaceans, amphipods (sand-hoppers), polychaete worms, bivalve molluscs like the Pipi, and gastropod molluscs (snails). Numerous microscopic organisms live on and between the sand grains that make up a beach. The most abundant animal groups are the marine worms (nematodes), followed by crustaceans and shellfish.
Few studies relating to the monitoring of beach species have been published, and providing an overview of beach condition (even of selected reference sites) is a long way off. Quantifying beach species is complicated by the fact that animals and plants distribute themselves three-dimensionally (depth and surface position) on a beach, and many species actively migrate up and down a beach according to the state of the tide.
The major pressures on sandy beaches and dunes are urbanisation and developments associated with tourism. Other uses that place pressure on beaches and dunes are sand mining, structures such as groynes and breakwaters that impede sand movements, and recreational activities including vehicle access.
There can be severe effects on dune systems as a result of clearing and modification. In places such as the Gold Coast, there is very little unmodified coastal habitat remaining because of the pressures caused by urban settlements along the coastal strip.
Dune vegetation has been extensively cleared for urban development, agriculture and sand mining. For example in Tasmania, the beach/dune areas around urban centres (Hobart, Burnie, Devonport) are heavily modified. Other heavily modified beach dune areas in urban centres are Perth and Bondi Beach in Sydney. Port developments have also caused significant modification.