|Location||Australia, Northern Territory|
|Central coordinates||135o 3.19' East 12o 32.13' South|
|IBA criteria||A1, A4i|
|Altitude||0 - 10m|
|Year of IBA assessment||2009|
Summary Two surveys in relatively wet years have both counted over 300,000 birds, of which over half were Magpie Geese and unidentified egrets. Other waterbirds present in internationally significant numbers include Black-necked Stork, Brolga, Glossy, Australian White and Straw-necked Ibis, Radjah Shelduck, Pied Heron, Royal Spoonbill, and Grey-tailed Tattler and Great Knot on the adjacent stretch of Castlereagh Bay. The IBA also supports the near threatened Australian Bustard.
Site description This IBA includes the Arafura swamp, 450 km east of Darwin, and the coastal saline flats of Castlereagh Bay west to Milingimbi, but not the tropical savanna in the surrounding catchment. The north-west boundary opposite the island of Milingimbi and the north-east boundary at the mouth of the swamp are based on the shorebird surveys of Chatto (2003). The site is in the wet tropics with an average of 1600 mm of rain along the coast during December to March. The swamp is fed by the Goyder and Gulbuwangay Rivers which terminate at the southern end of the swamp where the water disperses across a broad floodplain which narrows at the coast where it is constricted by bedrock. The swamp receives and retains water throughout the year and the Goyder River has the second-highest dry-season flow of any river in the Northern Territory. During the wet season there are extensive floods across the coastal plain where the swamp empties into the sea.
Key Biodiversity Brennan et al. (2003) estimated 300,000 waterbirds in Arafura Swamp on both of two aerial surveys, including about 130,000 unidentified egrets in both 1998 and 2000. Chatto (2000) identified six small waterbird colonies supporting eight species, with maximum counts of 150 and 300+ Royal Spoonbills. Brennan et al. (2003) recorded a colony of 500-1000 Australian White Ibis and estimated a minimum of 1200 Magpie Goose nests. The following records of threatened species are from outside the IBA boundary and may not constitute resident populations: one Gouldian Finch was recorded in 1980, one Northern (Crested) Shrike-tit was seen in 1990, there were two records of Partridge Pigeon in 1990 and six records of Hooded Parrot in the last 20 years (Brennan et al. 2003). Chatto (2003) recorded significant numbers of waders on the coastal salt flats in the north-west of the IBA but numbers are unknown. Other high counts include 500 Great Egrets and 7500 Cattle Egrets (Chatto 2006). White-gaped Honeyeaters and Long-tailed Finches have also been recorded at the swamp (Atlas of Australian Birds database).
Non-bird biodiversity: Brennan et al. (2002) recorded five native fish, 220 bird, 39 mammal, 72 reptile, 23 frog and 1,324 plant species in the wider Arafura catchment. These include the Vulnerable False Water Rat Xeromys myoides and a form of the Banded Rainbowfish Melanotaenia trifasciata which is endemic to the Goyder River. The IBA also holds numerous sites of high cultural value.
|Species||Season||Period||Population estimate||Quality of estimate||IBA Criteria||IUCN Category|
|Magpie Goose Anseranas semipalmata||resident||1998-2000||65,000-123,000 individuals||medium||A4i||Least Concern|
|Radjah Shelduck Radjah radjah||resident||1998-2000||667-2,500 individuals||medium||A4i||Least Concern|
|Black-necked Stork Ephippiorhynchus asiaticus||resident||1998-2000||585 individuals||medium||A1, A4i||Near Threatened|
|Australian Ibis Threskiornis moluccus||resident||1998-2000||22,680-49,000 individuals||-||A4i||Least Concern|
|Straw-necked Ibis Threskiornis spinicollis||resident||1998-2000||300-25,000 individuals||-||A4i||Least Concern|
|Glossy Ibis Plegadis falcinellus||resident||1998-2000||3,690-25,000 individuals||-||A4i||Least Concern|
|Royal Spoonbill Platalea regia||resident||1998-2000||252-1,323 individuals||-||A4i||Least Concern|
|Pied Heron Egretta picata||resident||1998-2000||2,644-15,544 individuals||poor||A4i||Least Concern|
|Australian Bustard Ardeotis australis||resident||1998-2008||common||-||A1||Least Concern|
|Brolga Antigone rubicunda||resident||1998-2000||2,220-7,300 individuals||-||A4i||Least Concern|
|Grey-tailed Tattler Tringa brevipes||non-breeding||1990-2002||800 individuals||-||A4i||Near Threatened|
|Great Knot Calidris tenuirostris||non-breeding||1990-2002||4,500 individuals||-||A4i||Vulnerable|
|2008||medium||not assessed||not assessed|
|Poor - based on little, or potentially unreliable/unrepresentative, data|
|Climate change and severe weather||storms and floods||likely in long term (beyond 4 years)||some of area/population (10-49%)||slow but significant deterioration||medium|
|Invasive & other problematic species, genes & diseases||invasive non-native/alien species/diseases - named species||happening now||some of area/population (10-49%)||slow but significant deterioration||medium|
|IUCN habitat||Habitat detail||Extent (% of site)|
|Forest||Melaleuca forests & woodlands||major|
|Wetlands (inland)||Riverine floodplains||major|
|Coastline||Intertidal mud, sand & salt flats||minor|
Land ownership Arnhemland ALT
|Land-use||Extent (% of site)|
|Notes: Traditional use|
Access/Land-Owner requests This IBA is on Traditionally Owned land.
Acknowledgements The Yolngu people supported the research and publication of Brennan et al.(2003).
References Brennan, K., Woinarski, J., Hempel, C., Cowie, I. and Dunlop, C. (2003) Biological inventory of the Arafura swamp and catchment. Unpublished report: Natural Systems Biodiversity Unit, Northern Territory Government, Darwin.
Chatto, R. (2000) Waterbird breeding colonies in the Top End of the Northern Territory. Technical Report 69, Parks and Wildlife Commission of the Northern Territory, Palmerston.
Chatto, R. (2003) The distribution and status of shorebirds around the coast and coastal wetlands of the Northern Territory. Technical Report 73, Parks and Wildlife Commission of the Northern Territory, Palmerston.
Chatto, R. (2006) The distribution and status of waterbirds around the coast and coastal wetlands of the Northern Territory. Technical Report 76, Parks and Wildlife Commission of the Northern Territory, Palmerston.
DEWHA (2008) Directory of Important Wetlands in Australia. http://www.environment.gov.au/water/publications/environmental/wetlands/database/ accessed 2008.
Harrison, L., McGuire, L., Ward, S. Fisher, A., Pavey, C., Fegan, M. and Lynch, B. (2009) An inventory of sites of international and national significance for biodiversity values in the Northern Territory. Department of Natural Resources, Environment, the Arts & Sport, Darwin, NT.
Ward, S. and Harrison, L. (2009) Recognising sites of conservation significance for biodiversity values in the Northern Territory. Department of Natural Resources, Environment, the Arts & Sport, Darwin, NT.
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