Sites - Important Bird Areas (IBAs)

Summary The IBA is an ephemeral wetland system that is estimated to have supported more than 200,000 waterbirds when extensively inundated. The system has periodically supported more than 1% of the global populations of Australian Pelican and Straw-necked Ibis. The inland breeding colonies of Australian Pelican and Straw-necked Ibis observed in the IBA are among the largest recorded for tropical Australia.

Ornithological information The IBA supports large numbers of waterbirds when conditions are suitable, e.g. up to 269,000 waterbirds may have been present during a major flood event in 2001-2002. At least 50 species of waterbird have been recorded, and 17 of these species are known to breed, in the IBA (Jaensch & Bellchambers 1997; Wetlands International, unpublished data provided by R. Jaensch). Species recorded in notable but sub-threshold numbers are Freckled Duck (84 on 29 March 2006), Great Egret (several thousand in 2001-2002 and 2006), Glossy Ibis (possibly more than 10,000 in March 2006) and Gull-billed Tern (1300 in 1995) (Jaensch & Bellchambers 1997; Wetlands International, unpublished data provided by R. Jaensch). Species observed in many thousands, but not confirmed to exceed thesholds, include the Magpie Goose, Plumed Whistling-Duck, Grey Teal, Hardhead and Intermediate Egret (R. Jaensch pers. comm. 2007). The nationally vulnerable Australian Painted Snipe bred at Tarabool Lake in 1993 (Jaensch 2003a), this representing the first breeding record for the species in the Northern Territory (R. Jaensch pers. comm. 2007). A breeding event involving 1500 pairs of Great Egret at Eva Downs Swamp in 2001 (Jaensch & Bellchambers 1997; Wetlands International, unpublished data provided by R. Jaensch) may be the largest documented breeding effort by this species in inland tropical Australia (R. Jaensch pers. comm. 2007).

Site description The IBA is comprised of Tarrabool Lake and an unnamed swamp to the north-west of Tarrabool Lake on Eva Downs Station (unofficially titled Eva Downs Swamp). In wetter years, these two water bodies become broadly connected to form a single massive freshwater wetland of up to 275,000 ha. Tarrabool Lake and Eva Downs Swamp are seasonally inundated, but may retain water for 12 consecutive months (or more in the case of Tarrabool Lake) after major flood events. Tarrabool Lake is dominated by low sparse to open Coolibah woodland, with extensive open Lignum shrubland (often under Coolibah woodland) in the centre-east, large areas devoid of trees in the centre-north and centre-south, and smaller open areas elsewhere, and some patches of open Northern Bluebush shrubland. The heart of Eva Downs Swamp is dominated by open Belalie woodland, mostly in association with open Lignum shrubland, and is surrounded by open Northern Bluebush shrubland; and there is tall tussock grassland to the south-east, with some open Coolibah woodland on the southern margin. Ground-cover plants such as Schoenoplectus dissachanthus can grow prolifically on drying or marshy areas of the system, and Nardoo is common (DEWHA 2007; R. Jaensch pers. comm. 2007).

Populations of IBA trigger species

Habitats

Land ownership Four pastoral leasehold properties (Anthony Lagoon, Rockhampton Downs, Brunchilly and Eva Downs) managed by companies including Australian Agricultural Company and Heytesbury Beef.

Land use

Other biodiversity At least seven faunal species recorded in the Tarabool Lake-Eva Downs region are listed under international conventions or bilateral agreements protecting migratory animals .

Management considerations Undertake development of a wetlands management strategy with landholders to identify additional stock exclusion areas and appropriate management of wetlands to maintain conservation values (NRETA 2005). Such a strategy should include prescriptions for fire management and to minimise the impact of livestock on natural values. Develop a conservation agreement and concept plan with landholders to include the wetlands in the reserve system. In cooperation with landholders, research the value of the wetlands for potential nomination as a wetland of international importance under the Ramsar convention (NRETA 2005).

Protection status None.

Conservation response Tarabool Lake and Eva Downs Swamp are listed on the Register of the National Estate and the Directory of Important Wetlands in Australia (DEWHA 2007) and are classified as sites of conservation significance by the Northern Territory Government (Harrison et al. 2009; Ward & Harrison 2009). Since 1993, Wetlands International has conducted irregular surveys of waterbirds following major flood events (R. Jaensch pers. comm. 2007). A 35 km stretch of Cresswell Creek, which lies north of the IBA but drains into Tarrabool Lake, was sprayed with herbicide in 2005 to treat Parkinsonia aculeata infestations. Follow-up work to treat infestations is ongoing with permanent points established to monitor the success of the program (Barkly Landcare and Conservation Association 2006; Harrison et al. 2009). Livestock are excluded from part of Eva Downs Swamp during periods of inundation. Fire on the tropical savannas is mapped continuously under the North Australia Fire Information Project. A number of tier 1 rangeland monitoring points are located in the Tarrabool Lake-Eva Downs Swamp region (Harrison et al. 2009).

Access/Land-Owner requests The IBA is located on privately-owned land with public access at the discretion of landholders.

Acknowledgements Roger Jaensch of Wetlands International provided unpublished data, comments and interpretation on the habitat and waterbird information.

References Barkly Landcare and Conservation Association (2006) Environment NT grant: Tarabool Lake project - treating Parkinsonia. Paddock Notes 1(1): 10. DEWHA (2007) A Directory of Important Wetlands in Australia. http://www.environment.gov.au/water/publications/environmental/wetlands/database/ accessed 2 October 2007. 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. Jaensch, R. (2003a) Recent records and breeding of Painted Snipe Rostratula benghalensis in the Mitchell Grass Downs and Sturt Plateau, Northern Territory. Northern Territory Naturalist 17: 31-37. Jaensch, R. (2003b) Breeding by Freckled Duck Stictonetta naevosa, and a review of recent records, in the Barkly wetlands, Northern Territory. Northern Territory Naturalist 17: 38-42. Jaensch, R. and Bellchambers, K. (1997) Waterbird conservation values of ephemeral wetlands of the Barkly Tableland, Northern Territory. Unpublished report to Australian Heritage Commission and Parks & Wildlife Commission of the Northern Territory. NRETA (2005) Draft Northern Territory parks and conservation masterplan. Darwin: Department of Natural Resources, Environment and the Arts. 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 (2013) Important Bird Areas factsheet: Tarrabool Lake-Eva Downs Swamp System. Downloaded from http://www.birdlife.org on 19/06/2013

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