Arafura Swamp (23413)
Australia, Australasia

Site overview

KBA status: confirmed

Global KBA criteria: A1a, A1c, B1, D1a

Year of last assessment: 2009

National site name: Arafura Swamp

Central coordinates: Latitude: -12.5355, Longitude: 135.0532

System: freshwater, marine, terrestrial

Elevation (m): 0 to 10

Area of KBA (km²): 917.49169

KBA classification: Global

Legacy site: Yes

Site details

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.

Rationale for qualifying as KBA: This site qualifies as a Key Biodiversity Area of international significance that meets the thresholds for at least one criterion described in the Global Standard for the Identification of KBAs.

Additional 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.

Other site values: Arnhemland ALT. This IBA is on Traditionally Owned land.

Habitats

IUCN Habitat	Coverage %	Habitat detail
Marine Intertidal	5
Forest	48
Wetlands(Inland)	48

Threats

Summary of threats to biodiversity at KBA: The cattle at the north of the swamp must be fenced away from the fragile banks and waterways separating the tidal and freshwater sections. Community ranger weed management programs should be supported to continue and strengthen their quarantine, awareness and surveillance activities whilst maintaining their control of Mimosa pigra and other weeds.

Threat level 1	Threat level 2	Threat level 3	Timing
Invasive & other problematic species, genes & diseases	Invasive non-native/alien species/diseases	Named species	Ongoing
Climate change & severe weather	Storms & flooding		Only in the future

Additional information

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.