Houtman Abrolhos (23919)
Australia, Australasia
Site overview
KBA status: confirmed
Global KBA criteria: A1b, B1, D1a
Year of last assessment: 2009
National site name: Houtman Abrolhos
Central coordinates: Latitude: -28.5067, Longitude: 113.7352
System: marine, terrestrial
Elevation (m): 0 to 15
Area of KBA (km2): 6.15009
Protected area coverage (%): 91.65
KBA classification: Global
Legacy site: Yes
Site details
Site description: The IBA consists of the entire archipelago of about 150 islands, islets and rocks most of which are used by seabirds for breeding. Major concentrations of breeding seabirds on Pelsaert (500,000+ pairs), Wooded, Morley and West Wallabi (1,000,000 Wedge-tailed Shearwater burrows) Islands. Other important islands include East Wallabi, Dick, Long, Gilbert, Helms, Leo, Sandy, Shearwater, Coronation and Lagoon Islands for Fairy Tern; and Pelsaert, Jon Jim, Square, Dick, First Sister and Post Office Islands for Roseate Terns. Of 192 islands surveyed in 2006, 148 (77%) had breeding seabirds. The three main island groups are the Wallabi, Easter and Pelsaert groups. The largest island is the 600 ha West Wallabi which is dominated by limestone pavement. Wooded and Morley are neighbouring islands in the Easter group; Wooded (19 ha) and Morley (9 ha) are limestone islands with central lagoons. Pelsaert, the southern-most island in the group, is a 120 ha coral cay. The archipelago comprises a mixture of limestone continental islands and sand or coral cays. Annual average rainfall is about 500 mm. The island group is a multiple purpose reserve for 'Conservation of Flora & Fauna, Tourism & for Purposes Associated with Fishing Industry' vested in the WA Minister for Fisheries, managed by the WA Department of Fisheries.
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: There have been two notable counts of Pied Cormorant: 550-900 pairs on nine islands in 1991 (Fuller et al. 1994) and 1436 pairs on eight islands in 2006/07 (Surman & Nicholson 2007). The islands also support the largest breeding colonies in Western Australia of Little Shearwaters, White-breasted Sea-Eagles (estimated 25 pairs), Osprey (estimated 42 pairs), Caspian Terns, and Crested Terns (Storr et al. 1986; Surman & Nicholson 2007). Breeding participation and success for many species greatly influenced by the Leeuwin Current; in some years breeding greatly reduced. Non-bird biodiversity: Tammar Wallaby Macropus eugenii and Southern Bush Rat Rattus fuscipes occur on East and West Wallabi Islands. Endemic subspecies of Spiny-tailed Skink Egernia stokesii stokesii occurs on several islands.
Other site values: Federal Government - Current reservation for flora and fauna conservation, tourism and fishing industry, managed by WA Department of Fisheries.
Habitats
Land use: fisheries/aquaculture (20%) | nature conservation and research (75%) | tourism/recreation (5%)
| IUCN Habitat | Coverage % | Habitat detail |
|---|---|---|
| Forest | 1 | |
| Marine Coastal/Supratidal | 88 | |
| Shrubland | 10 | |
| Marine Intertidal | 1 |
Threats
Summary of threats to biodiversity at KBA: Important seabird islands should be reserved for nature conservation. Seabird population monitoring needs to be continued.
| Threat level 1 | Threat level 2 | Threat level 3 | Timing |
|---|---|---|---|
| Human intrusions & disturbance | Recreational activities | Ongoing |
Additional information
References: Burbidge, A.A. and Fuller, P.J. (1989) Numbers of breeding seabirds on Pelsaert Island, Houtman Abrolhos, Western Australia. Corella 13, 57-61. Burbidge, A.A. and P.J. Fuller. (2004) Numbers of non-burrowing breeding seabirds of the Houtman Abrolhos: 1991-1993 and 1999. Corella 28: 96-103. Fuller, P.J., Burbidge, A.A. and Owens, R. (1994) Breeding seabirds of the Houtman Abrolhos, Western Australia: 1991-1993. Corella 18: 97-113. Gaughan, D., Surman, C., Moran, M., Burbidge, A. and Wooller, R. (2002) Feeding ecology of seabirds nesting at the Abrolhos Islands, Western Australia. Final Report for Fisheries Research and Development Corporation Project 1998/203. Johnstone, R.E. and Coate, K. (1992) Wooded Island, Easter Group, Houtman Abrolhos, Western Australia. Seabird Islands No. 216. Corella 16: 155-159. Johnstone, R.E. and Storr, G.M. (1994) West Wallabi Island, Houtman Abrolhos, Western Australia. Seabird Islands No. 216. Corella 18: 56-60. Storr, G.M, Johnstone, R.E. and Griffin, P. (1986) Birds of the Houtman Abrolhos, Western Australia. Records of the Western Australian Museum 24: 1-42. Surman, C.A. (1998) Seabird breeding schedules at the Pelsaert group of islands, Houtman Abrolhos, Western Australia between 1993 and 1998. Records of the Western Australian Museum 19: 209-215. Surman, C. A. and Wooller, R. D. (2003) Comparative foraging ecology of five sympatric terns at a sub-tropical eastern Indian Ocean island. Journal of Zoology (London) 259: 219-230. Surman, C.A. and Nicholson, L.W. (2007) Survey of the Avifauna of the Houtman Abrolhos Archipelago, 2006/07. Unpublished report prepared for DEC, Geraldton by Halfmoon Biosciences.
Contributors: Chirs Surman and Lisa Nicholson kindly provided draft data from their 2006 surveys; Andrew Burbidge prepared the nomination.