Investigator Islands (24721)
Australia, Australasia

Site overview

KBA status: confirmed

Global KBA criteria: D1a

Year of last assessment: 2009

National site name: Investigator Islands

Central coordinates: Latitude: -33.7258, Longitude: 134.5020

System: marine, terrestrial

Elevation (m): 0 to 60

Area of KBA (km²): 46.54408

Protected area coverage (%): 23.37

KBA classification: Global

Legacy site: Yes

Site details

Site description: The Investigator Group is an archipelago comprised of three island groups off the western coast of the Eyre Peninsula. The northernmost of the three island groups lies 3 km offshore near Elliston. This group, which consists of Waldegrave (292 ha) and Little Waldegrave (32 ha) Islands, has calcanerite soils. The vegetation is mostly comprised of regenerating pasture (sheep were grazed on the island until 1967), with some areas of native shrubland dominated by Native Juniper and Coast Daisy-bush. The second of the three island groups lies 28 km offshore. This group consists of Flinders Island, which at 3642 ha is the largest island in the Investigator Group, and nearby Ward and Topgallant Islands. Flinders Island is leasehold land used for grazing. It has calcanerite and sandy soils and is mostly covered by pasture grasses, with some tourist accommodation and some small areas of heathland and Melaleuca woodland. Topgallant Island is a small island with very steep cliffs and some stunted shrubland. The vegetation of Ward Island consists of shrubland and heathland. The southernmost of the three island groups consists of Pearson Island (213 ha), the Veteran Isles (14 ha) and Dorothee Island (56 ha). Pearson Island is covered with shrubland and heathland and some interspersed patches of Casuarina and Melaleuca woodland. The Veteran Isles support low shrubland dominated by Marsh Saltbush and Twiggy Daisy-bush (Robinson et al. 1996). All islands of the IBA, with the exception of Flinders Island (leasehold) and Pearson Island (Lighthouse Reserve), are included in Waldegrave Islands Conservation Park or Investigator Group Conservation Park.

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: Large numbers of Short-tailed Shearwater (approximately 92,906 pairs in 1980) and White-faced Storm-Petrel (approximately 9426 pairs in 1980) breed within the IBA (Copley 1996). The Little Penguin also breeds within the IBA on Waldegrave (more than 300 pairs in one small area in 1991), Little Waldegrave (common in 1979; 2001-2006), Pearson (many burrows in 1976) and Dorothee (many burrows on northern half of island in 1976) Islands (Parker & Cox 1978; Copley 1996; Shaughnessy et al. 2008a). The biome-restricted Rock Parrot has been observed on most islands in the group. It was the second most common species of bird recorded on Pearson Island by Hornsby (1978) but numbers may be smaller than the reporting rate indicates. More than 50 Rock Parrots were recorded on each visit to Little Waldegrave in 2001-2006, with a maximum of 200 breeding in 2002 (Shaughnessy et al. 2008b). Non-bird biodiversity: The IBA supports large numbers of Australian Sea-lions, smaller numbers of New Zealand Fur-seals, and the founding colony of the Pearson Island subspecies of the Black-footed Rock-wallaby.

Other site values: Flinders Island is leasehold. Other islands are owned and managed by the South Australian government.

Habitats

Land use: nature conservation and research | rangeland/pastureland

IUCN Habitat	Coverage %	Habitat detail
Artificial - Terrestrial	50
Shrubland	50

Threats

Summary of threats to biodiversity at KBA: Monitor all islands for invasive species such as rats, and eradicate where possible. Investigate the impact of human disturbance, including fishing and farming, on key species.

Threat level 1	Threat level 2	Threat level 3	Timing
Invasive & other problematic species, genes & diseases	Invasive non-native/alien species/diseases	Unspecified species	Ongoing
Human intrusions & disturbance	Recreational activities		Ongoing

Additional information

References: Copley, P.B. (1996) The status of seabirds in South Australia. Pp. 139-180. In: Ross, G.J.B., Weaver, K. and Greig, J.C. (eds) The Status of Australia's Seabirds. Biodiversity Group, Environment Australia: Canberra. Department for Environment and Heritage (2006) Island Parks of Western Eyre Peninsula Management Plan. Department for Environment and Heritage: Adelaide. Hornsby, P.E. (1978) Notes on the birds of Pearson Island. South Australian Ornithologist 27: 280-284. Parker, S.A. and Cox, J.B. (1978) Notes on the birds of Pearson, Dorothee and Greenly Islands, South Australia. Transactions of the Royal Society of South Australia 102: 191-202. Robinson, A.C., Delroy, L.B. and Jenkins, R.B. (1982) Conservation and Management of The Cape Barren Goose in SA. Unpublished report, Department of Environment and Natural Resources. Robinson, T., Canty, P., Mooney, T. and Ruddock, P. (1996) South Australia's Offshore Islands. Department of Environment and Natural Resources: Adelaide. Eckert, J. (1970) Birds of the Investigator Group with special reference to Flinders Island. South Australian Ornithologist 25: 201-205. Shaughnessy, P., Dennis, T. and Armstrong, D. (2008a) West Waldegrave Island, Eyre Peninsula, South Australia. Corella 32: 20-21. Shaughnessy, P., Dennis, T., Armstrong, D. and Berris, S. (2008b) Land-birds of three islands off the west coast of Eyre Peninsula, South Australia: Lilliput, Nicholas Baudin and West Waldegrave. Corella 32: 17-19. Stokes, A., Arnold, C., Urban and St John, B. (2002) Management of Cape Barren Geese in agricultural landscapes in South Australia - population estimate and cull limits for 2002. Unpublished report, Department for Environment and Heritage.