Australian mangroves

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Australian mangroves
Mangrove - Cooktown, Queensland, Australia.jpg
Mangrove in Cooktown, Queensland, Australia
Ecology
Realm Australasian realm
Biome mangroves
Geography
Country Australia
States
Mangroves on the Kalang River, Urunga, New South Wales. Mangroves at Urunga, NSW.jpg
Mangroves on the Kalang River, Urunga, New South Wales.

Australia has coastal areas where mangrove thickets and swamps occur, such as in the intertidal zones of protected tropical, subtropical and some temperate coastal rivers, river deltas, estuaries, lagoons and bays. [1] Less than 1% of Australia's total forested area consists of mangroves. [1]

Contents

Although mangroves are typically found in warmer, subtropical to tropical tidal areas, [2] there are occurrences as far south as Millers Landing in Wilsons Promontory, Victoria [3] (38°54′S), [4] Barker Inlet in Adelaide, South Australia [5] and Leschenault Inlet (Koombana Park), near Bunbury, Western Australia. [6]

Nearly half of Australia's mangrove forests are found in subtropical and tropical areas of coastal Queensland (44% of the continent's total), followed by the Northern Territory (37%) and Western Australia (17%). [1]

In Western Australia, mangroves are scattered along the coast; the mangroves of the Abrolhos Islands are 300 kilometres south of the next-nearest site at Shark Bay. The mangroves at Bunbury are even further south than this (500 km). The Bunbury mangrove colonisation may have occurred relatively recently, perhaps only several thousand years ago, with propagules likely transferred by the Leeuwin Current. [7] The most inland occurrence in Australia is a growth of grey mangrove (Avicennia marina) at Mandora Marsh, some 60 km from the coast.

Flora

A mangrove tree surrounded by its pneumatophores, Moreton Bay, Queensland Mangrove and pneumatophores in Moreton Bay, Qld.JPG
A mangrove tree surrounded by its pneumatophores, Moreton Bay, Queensland

Australian mangrove forests comprise 45 species across 18 families, which is more than half of the world's total mangrove species. [8] One species, Avicennia integra, is found only in Australia, in the Northern Territory, east of Darwin. [6]

Each mangrove species is specific to particular coordinates as well as to its own unique levels of tidal inundation. [1] The greatest diversity of species is found on the far northern and north-eastern coasts of Australia, becoming sparser with increasing latitude. [9] For example, Darwin Harbour, in the north of Australia, contains 36 mangrove tree species, [10] while Bunbury, in the south, contains only one mangrove tree species. There are no mangroves in Tasmania. [10]

The most widespread and common mangrove tree in Australia is the grey mangrove or white mangrove ( Avicennia marina ). [1]

Mangrove forests also support several salt-tolerant plant species which are not classed as mangroves. In tropical areas, this may include the mangrove palm ( Nypa fruticans ), the mangrove fern ( Acrostichum speciosum ), and orchids which grow as epiphytes on the trunks and branches of mangrove trees. [1] Other plants found in association with mangroves include the mangrove lily ( Crinum pedunculatum ). [11]

Mangrove forests share the high intertidal zone niche with coastal or intertidal saltmarshes; plant communities dominated by salt-resistant or salt-tolerant herbs and low shrubs. [12]

Associated fauna

Mangrove forests provide breeding nurseries for a wide range of fish and crustaceans, including many species of commercial and recreational value, for example, barramundi ( Lates calcarifer ), mangrove jack ( Lutjanus argentimaculatus ), mud crabs (Scylla serrata) and banana prawn ( Penaeus merguinensis ). [1] The forests also provide a habitat for spat settlement and development of oyster species. [13]

Many terrestrial fauna, such as insects, reptiles, frogs, birds and mammals, use mangroves for food, shelter, breeding and feeding grounds. [10]

The rusty monitor ( Varanus semiremex ) shelters in the hollows of mature or dead mangrove trees in north-eastern Queensland. [1] The mangrove snake ( Fordonia leucobalia ) and estuarine crocodile ( Crocodylus porosus ) are found in mangrove forests in the north.

The lesser noddy ( Anous tenuirostris melanops ) builds a platform nest of leaves in mangrove trees. This bird is listed as vulnerable under Australia's Environment Protection and Biodiversity Conservation Act 1999. [1]

Mangrove forests provide habitat for many small insectivorous birds, including the varied honeyeater, mangrove honeyeater, rufous-banded honeyeater, mangrove robin, lemon-bellied flycatcher, buff-sided robin, little shrike-thrush grey whistler, white-breasted whistler, northern fantail, mangrove grey fantail, Arafura fantail, broad-billed flycatcher, shining flycatcher, spectacled monarch, white-eared monarch and yellow white-eye. [14] Other bird species observed to frequent mangrove forests are the rose-crowned fruit-dove, little bronze-cuckoo, Papuan frogmouth, azure kingfisher, little kingfisher, forest kingfisher, Torresian kingfisher, sacred kingfisher and fawn-breasted bowerbird. [14]

Mangrove forests are sometimes used as nursery areas by flying foxes in the Darwin Harbour [10] and other areas of Australia. Several species, including the little red flying fox, are dependent on mangrove pollen as food. [10]

Economic values

Mangroves protect coastal areas from erosion, storm surge, and tsunamis. [15] [16] The massive root systems of mangroves are efficient at dissipating wave energy. [17] Mangroves retard the tidal movement of water, allowing sediment to be deposited as the tide comes in, and leaving all except fine particles when the tide ebbs. [18] Mangroves therefore build their own environment. [15]

The commercial and recreational fishing industries are prime beneficiaries of mangrove forests, which provide breeding and feeding grounds for fish and prawns. [1] About 75% of the fish and prawns caught for commercial and recreational purposes in Queensland spend at least part of their lifecycles in mangroves. [1]

In some coastal communities, boardwalks and bird-viewing areas in mangrove forests provide attractions for the eco-tourism industry, for example, at Boondall Wetlands. [1]

Threats

Threats to mangrove ecosystems include;

Removal of mangrove forests can lead to erosion of the shoreline, exposure of acid sulphate soils, shallowing of estuaries and waterways, and a reduction in water quality. [10] [20]

These threats can deplete the populations of fish, prawns, crabs and other sea life that use mangroves as breeding and feeding grounds, which would then impact on commercial and recreational fishing. [19]

Protection and preservation

About one-third of the total area of Australian mangrove forest is privately-owned, including indigenous reserves, [1] with around 18% of the total mangrove areas located within national parks or other officially protected areas. [1]

Mangroves are protected in Queensland under the Fisheries Act 1994, and in Western Australia under the Wildlife Conservation Act 1950.

As the benefits of mangroves become more widely known and valued, grassroots efforts to protect them are becoming more frequent. Boardwalks provide visual opportunities for visitors to experience the habitat, further educating the public on the ecological, economic and environmental necessities of mangroves. [1]

See also

Related Research Articles

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A mangrove is a shrub or tree that grows mainly in coastal saline or brackish water. Mangroves grow in an equatorial climate, typically along coastlines and tidal rivers. They have particular adaptations to take in extra oxygen and remove salt, allowing them to tolerate conditions that kill most plants. The term is also used for tropical coastal vegetation consisting of such species. Mangroves are taxonomically diverse due to convergent evolution in several plant families. They occur worldwide in the tropics and subtropics and even some temperate coastal areas, mainly between latitudes 30° N and 30° S, with the greatest mangrove area within 5° of the equator. Mangrove plant families first appeared during the Late Cretaceous to Paleocene epochs and became widely distributed in part due to the movement of tectonic plates. The oldest known fossils of mangrove palm date to 75 million years ago.

<span class="mw-page-title-main">Sundarbans</span> Mangrove forest in the Bay of Bengal

Sundarbans is a mangrove forest area in Ganges Delta formed by the confluence of the Ganges, Brahmaputra and Meghna Rivers in the Bay of Bengal. Spread across parts of India and Bangladesh, this forest is the largest mangrove forest in the world. It spans the area from the Baleswar River in Bangladesh's division of Khulna to the Hooghly River in India's state of West Bengal. It comprises closed and open mangrove forests, land used for agricultural purpose, mudflats and barren land, and is intersected by multiple tidal streams and channels. Sundarbans is home to the world's largest area of mangrove forests. Four protected areas in the Sundarbans are enlisted as UNESCO World Heritage Sites, viz. Sundarbans West (Bangladesh), Sundarbans South (Bangladesh), Sundarbans East (Bangladesh) and Sundarbans National Park (India).

<span class="mw-page-title-main">Roebuck Bay</span> Bay in Western Australia

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<span class="mw-page-title-main">Towra Point Nature Reserve</span> Protected area in New South Wales, Australia

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<i>Avicennia marina</i> Species of plant

Avicennia marina, commonly known as grey mangrove or white mangrove, is a species of mangrove tree classified in the plant family Acanthaceae. As with other mangroves, it occurs in the intertidal zones of estuarine areas.

<span class="mw-page-title-main">Coringa Wildlife Sanctuary</span> Sanctuary in Andhra Pradesh, India

Coringa Wildlife Sanctuary is an estuary situated near Kakinada in Andhra Pradesh, India. It is the third largest stretch of mangrove forests in India with 24 mangrove tree species and more than 120 bird species. It is home to the critically endangered white-backed vulture and the long billed vulture. Mangroves are a group of trees and shrubs that live in the coastal intertidal zone, with a dense tangle of prop roots that make the trees appear to be standing on stilts above the water. This tangle of roots allows the trees to handle the daily rise and fall of tides; hence, the mangrove forest gets flooded at least twice per day. The roots also slow the movement of tidal waters, causing sediments to settle out of the water and build up the muddy bottom.

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<span class="mw-page-title-main">New Guinea mangroves</span> Mangrove ecoregion that covers extensive areas of the coastline New Guinea

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<span class="mw-page-title-main">Ecological values of mangroves</span>

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Hungry Bay Nature Reserve is a nature reserve on the east coast of Bermuda. It was established in 1986. It is considered the best example of coastal mangrove swamp on the island. It includes the Hungry Bay area and the largest mangrove coastal swamp in Bermuda. It is protected by a Tree preservation order (T.P.O.) and designated as an official Nature Reserve within the Parks system of Bermuda.

<span class="mw-page-title-main">Solitary Islands Marine Park</span> Marine protected area in New South Wales, Australia

Solitary Islands Marine Park (SIMP) is a marine park in New South Wales State waters, Australia. It adjoins the Solitary Islands Marine Reserve and was declared under the Marine Parks Act 1997 (NSW) in January 1998. Prior to this it was declared a marine reserve in 1991. The Park was one of the first declared in NSW and stretches along the northern NSW coast, from Muttonbird Island, Coffs Harbour, to Plover Island near Sandon River, 75 kilometres to the north. It includes coastal estuaries and lakes and extends from the mean high water mark, to three nautical miles out to sea, covering an area of around 72,000 hectares. There are five main islands in the Park, North Solitary Island, North West Solitary Island, South West Solitary Island, South Solitary Island and Split Solitary Island, as well as other significant outcrops such as Muttonbird Island and submerged reefs.

<span class="mw-page-title-main">Isla Pulo</span>

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<span class="mw-page-title-main">Red River Delta Biosphere Reserve</span> Protected area in Vietnam

The Red River Delta Biosphere Reserve is a UNESCO biosphere reserve in the coastal region of northern Vietnam. Mangroves and intertidal habitats of the Red River Delta form wetlands of high biodiversity especially in the Xuan Thuy and Tien Hai districts. These wetlands are of global importance as migratory sites for several bird species.

<span class="mw-page-title-main">Gulf of Panama mangroves</span> Ecoregion along the Pacific coast of Panama and Colombia

The Gulf of Panama mangroves (NT1414) is an ecoregion along the Pacific coast of Panama and Colombia. The mangroves experience seasonal flooding with high levels of sediment, and occasional extreme storms or very low rainfall due to El Niño effects. They are important as a breeding or nursery area for marine species. Areas of the mangroves have been recognized as Important Bird Areas and Ramsar wetlands. The ecoregion has been severely degraded by clearance of mangroves for agriculture, pasturage and shrimp farming, by urban pressure around Panama City, and by pollution related to the Panama Canal.

<span class="mw-page-title-main">Cape York Peninsula tropical savanna</span> Region in Queensland, Australia

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Wide Bay Military Reserve is a heritage-listed military installation at Tin Can Bay Road, Tin Can Bay, Queensland, Australia. The reserve supports a diverse range of plant communities from estuarine, strand, wetlands, heath, tall shrublands and woodlands, to the open forests of the sub-coastal hills and ranges. The total number of bird species recorded for the place totals 250, which is high by Australian standards. It was added to the Australian Commonwealth Heritage List on 22 June 2004.

References

  1. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 "Department of Agriculture, Fisheries and Forestry , Bureau of Rural Sciences – Australian Forest Profiles: Mangroves". Archived from the original on 16 March 2011. Retrieved 23 January 2011.
  2. ↑ Mangal (Mangrove). World Vegetation. Mildred E. Mathias Botanical Garden, University of California at Los Angeles Archived 9 February 2012 at the Wayback Machine
  3. ↑ "Millers Landing". Victorian Resources Online:West Gippsland. Department of Primary Industries. Retrieved 30 March 2009.
  4. ↑ "Millers Landing". Geoscience Australia Place Names Search. Australian Government. Archived from the original on 17 April 2009. Retrieved 30 March 2009.
  5. ↑ Zann, Leon P. (1996) [1995]. "Mangrove ecosystems in Australia: structure, function and status". State of the Marine Environment Report for Australia. Australian Government, Dept of Environment and Heritage. ISBN   978-0-642-17399-7 . Retrieved 25 November 2006.
  6. 1 2 Duke, Norman (2006). Australia's Mangroves. Brisbane: University of Queensland & Norman C Duke. ISBN   0-646-46196-6.
  7. ↑ Rippey, Elizabeth; Rowland, Barbara (2004) [1995]. Coastal plants: Perth and the south-west region (2nd ed.). Perth: UWA Press. ISBN   978-1-920694-05-0.
  8. ↑ Duke, Norman (2013). World Mangrove ID: expert information at your fingertips. Brisbane: MangroveWatch Publications. ISBN   978-0-9923659-0-5.
  9. ↑ Suzuki, Kunio; Saeger, Peter (1996). "A phytosociological study of mangrove vegetation in Australia with a latitudinal comparison of East Asia". School of Environmental Science and Management Papers. Retrieved 23 January 2011.
  10. 1 2 3 4 5 6 Lee, Geraldine (2003). "Mangroves in the Northern Territory Report Number 25/2003D" (PDF). Northern Territory Department of Infrastructure, Planning and Environment. Archived from the original (PDF) on 29 March 2011. Retrieved 26 January 2011.
  11. ↑ Lovelock, Catherine; Clarke, Steve (1993). "Field Guide to the Mangroves of Queensland" (PDF). Australian Institute of Marine Science. Archived from the original (PDF) on 18 February 2011. Retrieved 23 January 2011.
  12. ↑ Neil Saintilan, ed. (2009). Australian Saltmarsh Ecology. CSIRO Publishing. ISBN   978-0-643-09371-3.
  13. ↑ "Primary Industries and Fisheries, Qld Government – Common Mangroves". Archived from the original on 6 January 2011. Retrieved 23 January 2011.
  14. 1 2 Simpson, Ken; Day, Nicolas; Trusler, Peter (2004). Field Guide to the Birds of Australia 7th Edition. Penguin Group (Australia). ISBN   978-0-670-04180-0.
  15. 1 2 Mazda, Y.; Kobashi, D. and Okada, S. (2005) "Tidal-Scale Hydrodynamics within Mangrove Swamps" Wetlands Ecology and Management 13(6): pp. 647–655
  16. ↑ Danielsen, F. et al. (2005) "The Asian tsunami: a protective role for coastal vegetation" Science 310: p. 643.
  17. ↑ Massel, S. R.; Furukawa, K.and Brinkman R. M. (1999) "Surface wave propagation in mangrove forests" Fluid Dynamics Research 24(4): pp. 219–249
  18. ↑ Mazda, Yoshihiro et al. (1997) "Drag force due to vegetation in mangrove swamps" Mangroves and Salt Marshes 1: pp. 193–199
  19. 1 2 3 4 5 6 7 Zann, Leon P. (1995) [1995]. "Marine Pollution". Our Sea, Our Future – Major findings of the State of the Marine Environment Report for Australia. Australian Government, Dept of Environment, Water, Heritage, and the Arts. ISBN   978-0-642-17391-1 . Retrieved 23 January 2011.
  20. ↑ "Mangrove Management in the Northern Territory" (PDF). Northern Territory Natural Resources, Environment, The Arts and Sport. Archived from the original (PDF) on 24 January 2011. Retrieved 26 January 2011.
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