A world of
Tidal Areas

Australia’s mangrove flora is uniquely rich,especially along the north coast. This is partly due to Australia’s proximity to species rich regions to the north. But, it also reflects regional influences of past changes over millions of years where massive continental fragments divided and rejoined mangrove communities. In the aftermath of such dramatic influences, mangroves flourish in Australia today because it is a large country affected by a range of climates with diverse temperature and rainfall conditions.

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Regional Influences in Australasia

Bruguiera Fruit

Mature propagule of
Bruguiera Sexangula.

The Australasian subregion includes: New Guinea, New Zealand, western Pacific islands, and Australia. Mangroves occur in a more-or-less continuous distribution along most coastal areas extending to temperate latitudes around the North Island of New Zealand and southern Australia. There are no obvious barriers to propagule dispersal. Nevertheless, there are notable patterns in diversity gradients shown in the map below. The diversity of mangroves in Australasia is maximal (>30 species, and up to 45) in the Indonesian-New Guinea archipelago extending to north eastern Australia. Beyond this, numbers drop-off in two distinct ways: numbers decline toward higher latitudes reflecting a temperature gradient where species have different limiting lower temperature tolerances; and, declining species numbers eastward where each is limited differently by dispersal range and niche availability.

Mangroves in Australia and Its Territories

Australia’s mangroves occur in all mainland States and Territories that have coastal boundaries, including Western Australia, the Northern Territory, Queensland, New South Wales, Jervis Bay Territory, Victoria, and South Australia. As seen in the Table (opposite), most species occur along the northern coast but they have differing ranges west and east. Some distributions are continuous and some are widespread, but others are restricted to particular local areas. Mangroves occur also in several Australian external territories offshore, including:- in the Tasman Sea - Lord Howe Island (31° 33’ S; 159° 05’ E) with a few scattered shrubs of Avicennia marina and Aegiceras corniculatum, and Norfolk Island (29° 02’ S; 168° 01’ E) with Excoecaria agallocha; in the Indian Ocean - the Cocos Islands (12° 10’ S; 96° 52’ E)Regional influences with Rhizophora apiculata (apparently introduced) and Pemphis acidula, and Christmas Island (10° 30’ S; 105° 39’ E) with Barringtonia racemosa, Bruguiera gymnorhiza, Bruguiera sexangula, Cynometra iripa, Heritiera littoralis and Pemphis acidula. Christmas island has an unusually elevated inland mangrove forest that appears relict of a time when sea levels were much higher. Hosnie’s Spring supports mangroves dominated by Bruguiera gymnorhiza and B. sexangula, some 120 metres inland of a seaward cliff, and approximately 24-37 m above sea-level. At Hosnie’s Spring, they attain a height of 40 m. Conditions favourable for normal mangrove establishment do not appear to have existed since the last interglacial period, implying this stand has persisted in its present location for up to 120,000 years.

Community Volunteers

A key feature of MangroveWatch is its close partnership between community volunteers and scientists from the James Cook University’s Mangrove Hub. Together they are systematically recording basic data as video and still imagery for assessments of estuarine habitat health.

Armed with expert support, training and advice, MangroveWatch volunteers in key regions are actively contributing to the monitoring of local estuaries and shorelines. An important goal in this phase of the program is to develop a network of like minded groups with the aim of producing public documents that describe important issues affecting local estuaries and mangroves, and their overall health.

Getting Involved

If you would like to find out more about us or if you like to initiate your own MangroveWatch group within your area, please contact someone at the Mangrove Hub. We will be happy to help.

  • Mangrove Hub Facilitator
  • Dr Norm Duke
  • MangroveWatch Ltd
    ABN: 44 153 297 771
  • PO Box 1250,
  • Elanora Q 4221
  • Mangrove Hub Email

Mangrove Watch Brochure

You can download our fact and information sheet (see link below) to get more information about the MangroveWatch programs.

Mangrove Watch Brochure