|Scientific Name:||Amphibolis antarctica|
|Species Authority:||(Labill.) Asch.|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Short, F.T., Carruthers, T.J.R., Waycott, M., Kendrick, G.A., Fourqurean, J.W., Callabine, A., Kenworthy, W.J. & Dennison, W.C.|
Amphibolis antarctica is endemic to southern Australia. The overall population size is thought to be stable. There are no major threats other than localized coastal development. This species is listed as Least Concern.
|Range Description:||Amphibolis antarctica is endemic to Australia and ranges from Shark Bay in mid-Western Australia to Bass Strait, including eastern Tasmania.|
|FAO Marine Fishing Areas:||
Indian Ocean – eastern
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Amphibolis antarctica is common in western and southern Australia. The population is thought to be overall stable.|
|Habitat and Ecology:||
Amphibolis antarctica is a seagrass that dominates (with Posidonia australis) the subtidal environment in western and southern Australia, in sandy lower-littoral pools and channels, to depths of about 12 m. In southeastern Australia, it forms patches of varying sizes at the mouth of some bays, and occurs in areas dominated by sandy siliceous sediments and exposed to ocean swells. It can be present to depths of 22 m in clear non-polluted water. It is a slow-growing seagrass.
The leaves of the shallow rock pool plants may float on the surface at low tide, becoming severely damaged or turning black, and then are cast off in the hot summer months (Ducker et al. 1977). Although usually described as occurring in areas of high water flow, Walker (1989) observed the species growing under "a wide range of current regimes". Amphibolis antarctica has been shown to be very tolerant of high salinity levels. Walker (1989) collected seedlings from areas of salinities up to 50 ppt. Although percentage cover was much reduced at the higher salinities, A. antarctica was observed growing at salinities of greater than 60 ppt, with an optimal range of 40-50 ppt (Walker 1989).
In the sub-littoral zone, A. antarctica may form extensive beds on sandy floors, sand covered rocks, gravel bottoms and, less frequently, on banks of firm, compact clay in places where the water is kept continually in motion by currents or wave action. Plants of the genus Amphibolis are dioecious and viviparous (Ducker et al. 1977).
Amphibolis antarctica has no known major threats. There may be some localized threat from human activities such as port and industrial development, pipelines, communication cables, mining and dredging.
Cockburn Sound, an area in the range of Amphibolis antarctica, has been subjected to steady degradation since 1954, with the establishment of an oil refinery and the successive establishments of steel works, fertilizer factories, sewage-treatment facilities, and a power station. This has lead to contaminated effluents and increased nutrient loads in the surrounding waters. Between 1954 and 1978 the seagrass meadow in this region decreased from 4,200 to 900 ha and leaf detritus production was reduced from 23,000 to 4,000 t (dry weight)/year. Seagrasses in this region include Posidonia sinuosa, P. australis, P. coriacea, Halophila ovalis, H. decipiens, Syringodium isoetifolium, Zostera tasmanica, Amphibolis griffithii, and A. antarctica (Cambridge and McComb 1984).
|Conservation Actions:||Amphibolis antarctica is protected in some Marine Protected Areas within Western Australia. It occurs in the Shark Bay World Heritage Area which contains more than 4,000 km² of seagrass beds of high density. It is also protected in the Australian Fisheries Act and Marine Park Act.|
Cambridge, M.L. and McComb, A.J. 1984. The loss of seagrasses in Cockburn Sound, Western Australia. I. The time course and magnitude of seagrass decline in relation to industrial development. Aquatic Botany 20: 229-243.
Ducker, S.C., Foord, N.J. and Knox, R.B. 1977. Biology of Australian seagrasses: the genus Amphibolis C. Agardh (Cymodoceaceae). Australian Journal of Botany 25: 67-95.
Green, E.P. and Short, F.T. 2003. World Atlas of Seagrasses. University of California Press, Berkeley.
IUCN. 2010. IUCN Red List of Threatened Species (ver. 2010.3). Available at: http://www.iucnredlist.org. (Accessed: 2 September 2010).
Walker, D.I. 1989. Regional studies - seagrass in Shark Bay, the foundations of an ecosystem. In: A.W.D. Larkum, A.J. McComb and S.A. Shepherd (eds), Biology of Seagrasses. A treatise on the biology of seagrasses with special reference to the Australian region, pp. 182-210. Elsevier, Amsterdam.
|Citation:||Short, F.T., Carruthers, T.J.R., Waycott, M., Kendrick, G.A., Fourqurean, J.W., Callabine, A., Kenworthy, W.J. & Dennison, W.C. 2010. Amphibolis antarctica. The IUCN Red List of Threatened Species. Version 2015.2. <www.iucnredlist.org>. Downloaded on 29 August 2015.|
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