Alligator Rivers Floodplains

Country/territory: Australia

IBA Criteria met: A1, A2, A3, A4i (2009)
For more information about IBA criteria please click here

Area: 383,151 ha

Protection status:

BirdLife Australia
Most recent IBA monitoring assessment
Year of assessment Threat score (pressure) Condition score (state) Action score (response)
2008 high not assessed not assessed
For more information about IBA monitoring please click here

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).

Key biodiversity
Other high counts of birds (c.60% of IBA counted) included: 3000 White-necked Heron, 15,000 Australian White Ibis, 2,000 Darter, 1,000 Common Sandpiper and 2,300 Gull-billed Tern (Morton et al. 1989). Chatto (2000) listed numbers of nesting waterbirds at seven colonies, totalling at least 13,500 Intermediate Egret (but probably many 1000s more), 6,560 Great Egret, 1,080 Little Egret, 5,550 Cattle Egret (but probably many 1000s more), 7,250 Pied Heron, 1,500 Rufous Night-Heron, 3,800 Little Pied Cormorant and 4,200 Australian White Ibis. Chatto (2003) recorded 7,000 waders in Finke Bay in September 1993. The saline swamps and flats support unknown numbers of Yellow Chats which is otherwise very rare away from inland Australia.

Non-bird 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.

Recommended citation
BirdLife International (2021) Important Bird Areas factsheet: Alligator Rivers Floodplains. Downloaded from on 23/01/2021.