Rottnest Island (24836)
Australia, Australasia

Site overview

KBA status: confirmed

Global KBA criteria: A1b, D1a

Year of last assessment: 2009

National site name: Rottnest Island

Central coordinates: Latitude: -32.0073, Longitude: 115.5108

System: marine, terrestrial

Elevation (m): 0 to 40

Area of KBA (km²): 18.83957

Protected area coverage (%): 100.00

KBA classification: Global

Legacy site: Yes

Site details

Site description: The whole of Rottnest Island, a 11 kilometres long and 19 km off Perth, is taken as an IBA. Although the key IBA bird species only utilise the coast and lagoons, management of these habitats is best addressed at a whole-island scale. The island is comprised of limestone and sand, and dominated by low scrubby vegetation with several large permanent salt lakes. The six permanent salt lakes cover about 200 hectares or about 10 percent of the Island’s surface and ranging from two to seven metres in depth. There are also eight seasonally fresh to brackish ephemeral swamps, all of which have been heavily modified by mining, salinisation and eutrophication except for Barker Swamp. The island receives an average of about 800 mm annual rainfall. The whole island is a Class A Reserve for 'Recreation', managed by the Rottnest Island Authority; although the authority promotes and implements biodiversity conservation work, this is not a protected area under IUCN criteria. This reserve includes several smaller Islands and exposed rocks, which could qualify within the IBA is proved to support Fairy Terns, and about 3810 hectares of sea. The island is a popular day-trip from Perth and more than 500,000 people visit each year. As Red-necked Stints move between Rottnest and the Swan Estuary at Perth, a conservation area for this species could include the Swan Estuary.

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: One hundred and twelve species of bird have been recorded on or around Rottnest Island (Saunders & de Rebeira 1985, 1993). The island is a major breeding site for the congregatory Wedge-tailed Shearwater and its numbers are increasing: in 1993, four colonies were located at the western end of the island, comprising a total 5865 nesting burrows (Sims 1993), and in 2002, six colonies were located, comprising a total 11,745 nesting burrows (Bancroft et al. 2004). The island also supports notable numbers of the congregatory Red-necked Stint with counts of 438 in 1998, 1125 in 1999, 1504 in 2000, 1324 in 2001, 1380 in 2002, 958 in 2003, 978 in 2004, 791 in 2005, 1331 in 2006, 1207 in 2007 and 852 in 2008. The biome-restricted Rock Parrot is uncommon on the island (Atlas of Australian Birds database). Non-bird biodiversity: Rottnest Island supports two species of native mammal, seventeen species of reptile, three species of frog and at least 16 species of butterfly, 15 species of spider and 42 species of ant. The island supports the largest known population (estimated 8000-12,000 individuals) of the globally threatened Quokka (Setonyx brachyurus) (Rottnest Island Authority 2003).

Other site values: Western Australian State Government with management the responsibility of the Rottnest Island Authority.

Habitats

Land use: tourism/recreation | urban/industrial/transport

IUCN Habitat	Coverage %	Habitat detail
Shrubland	48
Marine Coastal/Supratidal	5
Forest	48

Threats

Summary of threats to biodiversity at KBA: Ensure that salt lakes are protected and managed for conservation in the face of ongoing tourism development. Investigate measures to protect Fairy Tern colonies on beaches. Survey for Fairy Terns on small islets.

Threat level 1	Threat level 2	Threat level 3	Timing
Human intrusions & disturbance	Recreational activities		Ongoing
Residential & commercial development	Tourism & recreation areas		Only in the past and unlikely to return

Additional information

References: Bancroft, W.J., Garkakalis, M.J. and Roberts, D.J. (2004) Continued expansion of the Wedge-tailed Shearwater, Puffinus pacificus, nesting colonies on Rottnest Island, Western Australia. Emu 104: 79-82. O'Connor, F. (2002) Observations. Western Australian Bird Notes 101: 2-5. Rottnest Island Authority (2003) Rottnest Island management plan 2003-2008. Fremantle, Western Australia: Rottnest Island Authority. Saunders, D. and de Rebeira, P. (1985) Turnover in breeding bird populations on Rottnest Island, Western Australia. Australian Wildlife Research 12: 467-477. Saunders, D. and de Rebeira, P. (1993) The birdlife of Rottnest Island. Second revised edition. Guildford, Western Australia: Authors. Sims, C.V. (1993) Aspects of the population ecology of Wedge-tailed Shearwaters, Puffinus pacificus, on Rottnest Island W.A.: a comparative study. B.Sc. (Honours) thesis. Perth: Murdoch University.