Roebuck Bay (25153)
Australia, Australasia

Site overview

KBA status: confirmed

Global KBA criteria: A1a, A1c, B1, D1a

Year of last assessment: 2009

National site name: Roebuck Bay

Central coordinates: Latitude: -18.0477, Longitude: 122.4257

System: marine, terrestrial

Elevation (m): 0 to 15

Area of KBA (km²): 928.43415

Protected area coverage (%): 59.55

KBA classification: Global

Legacy site: Yes

Site details

Site description: The IBA is comprised of a large coastal plain and an adjacent bay with extensive intertidal flats just south of Broome in Western Australia. On particularly high tides, all intertidal shorebirds roost in and behind mangroves and on plains wetlands, so the plain is combined with the bay (unlike Eighty Mile Beach IBA and Mandora Marsh & Anna Plains IBA, which have been separated because of non-interchange of their birds). The intertidal mudflats extend from Entrance Point to Cape Villaret, and there is another stretch between Cape Villaret and Cape Gourdon. Roebuck Bay has a very large tidal range, which exposes around 160 square kilometres of mudflat, approximately 45% of the total bay area. The IBA also includes the coastal grasslands of Roebuck Plains Station, which are occasionally inundated by high tides and/or cyclonic rain, with full inundation about once every five to ten years. Water depth: when full, Lake Eda may be several metres deep but it dries back to a shallow pond in the dry season; all other areas are probably less than 1 m deep. The IBA also encompasses six additional separate areas that are important for the key birds: South Cable Beach, the inter-tidal coast from Cape Villaret to Cape Gourdon, and various small lakes to the east connected with the floodplain by watercourses: Lake Eda, Lake Campion, Taylors Lagoon and Collins Lagoon. Mean annual rainfall at Broome is 561 mm, mostly falling in December-March. The area around, and south of, the bay is in the Roebuck Bay Ramsar site.

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: Counts of up to 170,000 waders have been made in Roebuck Bay (Minton 2006). A single high count of 50,000 Oriental Pratincole in February 1989 (Hooper and Wells 1989); otherwise max count 6000 in 1986 (Collins and Jessop 2001). Also a single high count of 13,560 Black-tailed Godwit in 2000; next highest count in period 1990-2008 was 7374 (Australian Shorebird Count Database). High counts of species not meeting 1% of global populations include 300 Brolga at Lake Eda in 1995 (R. Jessop in litt. 2008), 328 Broad-billed Sandpiper in 2005, 3658 Curlew Sandpiper in 2003 (and a historical maximum of 6000), 3762 Red Knot in 2001, 371 Common Greenshank in 2000, 3680 Terek Sandpiper in 2003, 834 Ruddy Turnstone in 2001, over 2000 Sharp-tailed Sandpiper in 1998, 1999 and 2000, 1780 Gull-billed Tern in 2003, 1225 Little Tern in 2005 and 1072 Whiskered Tern in 2005 (Australian Shorebird Count Database; Lane 1987; Rogers et al. 2001; Rogers et al. 2006a). The IBA supports sub-threshold numbers of Whiskered Tern but is considered to be an important breeding site for this species when conditions are suitable (C. Minton pers. comm.). Other notable species recorded in the IBA include the nationally threatened Australian Painted Snipe (max 15 at Lake Eda in 2005), the near threatened Bush Stone-curlew and Beach Stone-curlew, and the biome-restricted Varied Lorikeet, White-gaped Honeyeater, Yellow-tinted Honeyeater, Banded Honeyeater, Pied Honeyeater and Painted Finch, but none is present in the IBA in significant numbers (Collins 1995; Atlas of Australian Birds database). The rare Yellow Chat does occur in significant numbers (Collins 1995; P. Collins pers. comm. 2007) with a max count of 1060 at Kidneybean Claypan in 1999 (Rogers et al. 2001). The biome-restricted Australian Yellow White-eye is abundant in suitable habitat (Collins 1995; Collins pers. comm. 2007) and the biome-restricted Long-tailed Finch is frequent (Collins 1995; Collins pers. comm. 2007) with a count of 60 at Taylors Lagoon in 1995 (Collins & Jessop 2001).

Other site values: State or local government (Port of Broome); Crown Land under native title; some pastoral leases including Roebuck Plains Station. Permission must be obtained to access any of the pastoral stations.

Habitats

Land use: rangeland/pastureland | urban/industrial/transport | water management

IUCN Habitat	Coverage %	Habitat detail
Wetlands(Inland)	5
Forest	5
Marine Intertidal	28
Grassland	28
Shrubland	28
Savanna	5

Threats

Summary of threats to biodiversity at KBA: Minimise the impact of development and expansion of Broome township on birds that use this important area; especially disturbance of shorebird roosts on beaches.

Threat level 1	Threat level 2	Threat level 3	Timing
Residential & commercial development	Commercial & industrial areas		Ongoing

Additional information

References: Collins, P. (1995) The Birds of Broome – An Annotated List. Broome, Western Australia: Broome Bird Observatory. Collins, P. and Jessop, R. (2001) Waterbirds of Taylor’s Lagoon, near Broome, Western Australia. Stilt 39: 27-30. DEWHA (2008a) A Directory of Important Wetlands in Australia. Information Sheet on Ramsar Wetlands (RIS). Roebuck Bay, Western Australia-33. Downloaded from http://www.environment.gov.au/water/publications/environmental/wetlands/database/ accessed November 2008. DEWHA (2008b) Roebuck Plains System-WA021. Downloaded from http://www.environment.gov.au/water/publications/environmental/wetlands/database/ accessed November 2008. Hooper, G. and Wells, B. (1989) Broome Bird Observatory Report. Stilt 15: 3. Lane, B. (1987) Shorebirds in Australia. Melbourne: Nelson Publishers. Lane, B. and Jessop, A. (1985) Report on the 1985 North-west Australia Wader Studies Expedition. Stilt 6: 2-12. Lane, B., Minton, C. and Jessop, A. (1983) North-west Australia Wader Studies Expedition. Report to participants. Unpublished report. Melbourne: RAOU. Minton, C. (1987) Report on visit to NW Australia 21 March to 5 April 1987. Stilt 11: 6-12. Minton, C. (2006) The history of wader studies in north-west Australia. Stilt 50: 224-234. Minton, C. and Martindale, J. (1982) Report on wader expedition to north-west Australia in August/September 1981. Stilt 2: 14-26. Murlis, B., Murlis, M. and Swindley, B. (1988) Radar studies and counts at Broome/Roebuck Bay. Victorian Wader Study Group Bulletin 12: 15-18. Rogers, D., Battley, P.F., Piersma, T., van Gils, J. and Rogers, K.G. (2006) High-tide habitat choice: modelling the roost selection of shorebirds around a tropical bay. Animal Behaviour 72: 563-575. Rogers, D., Battley, P., Russell, M. and Boyle, A. (2000) A high count of Asian Dowitchers at Roebuck Bay, North Western Australia. Stilt 37: 10-12. Rogers, D., Boyle, A. and Hassell, C. (2001) Wader counts at Kidneybean Claypan and adjacent Roebuck Plains. Northwestern Australia. Stilt 38: 57-63. Rogers, D.I., Rogers, K.G., Gosbell, K.B. and Hassell, C.J. (2006a) Causes of variation in population monitoring surveys: insights from non-breeding counts in north-western Australia 2004-2005. Stilt 50: 176-193. Rogers, D.I., Piersma, T. and Hassell, C.J. (2006b) Roost Availability May Constrain Shorebird Distribution: Exploring the Energetic Costs of Roosting and Disturbance Around a Tropical Bay. Biological Conservation 133: 225-235. Tulp, I. and de Goeij, P. (1994) Evaluating wader habitats in Roebuck Bay (north-western Australia) as a springboard for northbound migration in waders, with a focus on Great Knots. Emu 94: 78-95.