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Location Australia, Northern Territory
Central coordinates 132o 32.32' East  12o 18.20' South
IBA criteria A1, A2, A3, A4i
Area 383,151 ha
Altitude 0 - 10m
Year of IBA assessment 2008

BirdLife Australia



Summary The extensive floodplains were well surveyed in 1981-1984; extrapolating these maximum estimates to the whole IBA suggest that it supported five million waterbirds, including more than 1% of the world population of 22 species, and significant numbers of three near threatened species, and another 11 restricted-range or savanna-biome-restricted species.

Site description The IBA covers four large adjacent floodplains on the Wildman, Love and Alligator creeks, and the South Alligator, East Alligator, Magela, Cooper and Murgenella rivers. All are primarily seasonally flooded freshwater floodplains, with extensive areas of saltwater floodplains and permanent freshwater swamps. The rivers are tidal in their lower reaches and are associated with extensive tidal flats formed from riverborne mud. Wetland colonies in Chatto (2000) ref: W028, 29, 34, 35, 36, 37, 66. Waterbirds will also use the smaller wetlands inland of these floodplains, which are included in the adjacent Kakadu Savanna IBA. The climate is monsoonal with a hot wet season from November to March accounting for, on average, 90% of the annual rainfall which ranges from approximately 1300-1565 mm (Ramsar information sheet). Kakadu National Park is extremely popular, attracting some 210,000 international and national tourists visit the park each year, a large proportion of whom visit some part or other of the wetlands (Ramsar fact sheet).

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Magpie Goose Anseranas semipalmata unknown  1981-1994  1,600,000 individuals  medium  A4i  Least Concern 
Plumed Whistling-duck Dendrocygna eytoni unknown  1981-1994  50,000 individuals  medium  A4i  Least Concern 
Wandering Whistling-duck Dendrocygna arcuata unknown  1981-1994  400,000 individuals  medium  A4i  Least Concern 
Radjah Shelduck Radjah radjah unknown  1981-1994  20,000 individuals  medium  A4i  Least Concern 
Green Pygmy-goose Nettapus pulchellus unknown  1981-1994  50,000 individuals  medium  A4i  Least Concern 
Pacific Black Duck Anas superciliosa unknown  1981-1994  60,000 individuals  medium  A4i  Least Concern 
Grey Teal Anas gracilis unknown  1981-1994  50,000 individuals  medium  A4i  Least Concern 
Black-necked Stork Ephippiorhynchus asiaticus unknown  1981-1984  1,800 individuals  poor  A1, A4i  Near Threatened 
Australian Ibis Threskiornis moluccus unknown  1981-1994  15,000 individuals  medium  A4i  Least Concern 
Straw-necked Ibis Threskiornis spinicollis unknown  1981-1994  80,000 individuals  medium  A4i  Least Concern 
Glossy Ibis Plegadis falcinellus unknown  1981-1994  60,000 individuals  medium  A4i  Least Concern 
Royal Spoonbill Platalea regia unknown  1981-1994  35,000 individuals  medium  A4i  Least Concern 
Mesophoyx intermedia unknown  1981-1994  200,000 individuals  medium  A4i  Not Recognised 
Pied Heron Egretta picata unknown  1981-1994  50,000 individuals  medium  A4i  Least Concern 
Australian Pelican Pelecanus conspicillatus unknown  1981-1994  50,000 individuals  medium  A4i  Least Concern 
Australian Bustard Ardeotis australis unknown  1998-2008  212 individuals  medium  A1  Least Concern 
Brolga Antigone rubicunda unknown  1981-1994  24,000 individuals  medium  A4i  Least Concern 
Bush Thick-knee Burhinus grallarius resident  1998-2008  frequent  A1  Least Concern 
Himantopus leucocephalus unknown  1981-1994  100,000 individuals  medium  A4i  Not Recognised 
Vanellus miles unknown  1981-1994  80,000 individuals  medium  A4i  Not Recognised 
Comb-crested Jacana Irediparra gallinacea unknown  1981-1994  25,000 individuals  medium  A4i  Least Concern 
Little Curlew Numenius minutus non-breeding  1981-1994  300,000 individuals  medium  A4i  Least Concern 
Sharp-tailed Sandpiper Calidris acuminata non-breeding  1990-2002  4,900 individuals  medium  A4i  Least Concern 
Australian Pratincole Stiltia isabella unknown  1981-1994  30,000 individuals  medium  A4i  Least Concern 
Whiskered Tern Chlidonias hybrida non-breeding  1981-1994  45,000 individuals  medium  A4i  Least Concern 
Varied Lorikeet Psitteuteles versicolor unknown  1998-2008  uncommon  A3  Least Concern 
Northern Rosella Platycercus venustus resident  1998-2008  uncommon  A3  Least Concern 
Rainbow Pitta Pitta iris resident  1998-2008  uncommon  A2, A3  Least Concern 
White-gaped Honeyeater Lichenostomus unicolor resident  1998-2008  abundant  A3  Least Concern 
Silver-crowned Friarbird Philemon argenticeps resident  1998-2008  uncommon  A3  Least Concern 
Bar-breasted Honeyeater Ramsayornis fasciatus resident  1998-2008  uncommon  A3  Least Concern 
Banded Honeyeater Certhionyx pectoralis resident  1998-2008  uncommon  A3  Least Concern 
Buff-sided Robin Poecilodryas cerviniventris resident  1998-2008  uncommon  A3  Least Concern 
Australian Yellow White-eye Zosterops luteus resident  1998-2008  uncommon  A3  Least Concern 
Masked Finch Poephila personata resident  1998-2008  uncommon  A3  Least Concern 
Long-tailed Finch Poephila acuticauda resident  1998-2008  frequent  A3  Least Concern 

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Kakadu National Park 1,980,400 protected area overlaps with site 248,294  

Habitats

IUCN habitat Habitat detail Extent (% of site)
Forest Melaleuca forests & woodlands  major
Shrubland Chenopod shrubs, samphire shrubs and forblands  minor
Coastline Intertidal mud, sand & salt flats; Mangrove wetlands  minor
Wetlands (inland) Riverine floodplains  major

Land ownership Kakadu NP owned by Traditional Owners and managed in partnership with National Parks; wetlands to east owned by Arnhemland ALT.

Land use

Land-use Extent (% of site)
other major
Notes: Traditional Use
nature conservation and research major

Other biodiversity Wetlands species listed in the Ramsar notification include false water rat Xeromys myoides, golden-backed tree rat Mesembriomys macrurus, pig-nosed turtle Carettochelys insculpta, Mariana's hardyhead Craterocephalus marianae, exquisite rainbow fish Melanotaenia exquisita, Midgley's grunter Pingalla midgleyi and the frog Megistolotes lignarius.

Protection status IBA overlaps Kakadu and Mary River National Parks.

Access/Land-Owner requests Much of this IBA is on private or Traditionally Owned land.

References Bamford, M.J. (1990). RAOU survey of migratory waders in Kakadu National Park: Phase III. Report to ANPWS. RAOU Report No. 70.

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.

A Directory of Important Wetlands in Australia (accessed March 2007) Kakadu National Park - NT017 Kakadu National Park management plans (website accessed March 2007) http://www.environment.gov.au/parks/kakadu/parkjointmang/mangprograms/index.html

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. Morton, S.R., Brennan, K.G. and Armstrong, M.D. (1989) Distribution and abundance of waterbirds on the Alligator Rivers Region, Northern Territory. Report to the Australian National Parks and Wildlife Service. Office of supervising scientist for the Alligator region, Jabiru, NT.

Smyth, D. (1995) Coming out Bright. An audit of research conducted in KNP 1992-1995. Australian Nature Conservation Agency, Jabiru. 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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Recommended citation  BirdLife International (2014) Important Bird Areas factsheet: Alligator Rivers Floodplains. Downloaded from http://www.birdlife.org on 28/08/2014

To provide new information to update this factsheet or to correct any errors, please email BirdLife