Hunter Island Group (23953)
Australia, Australasia

Site overview

KBA status: confirmed

Global KBA criteria: B1, D1a

Year of last assessment: 2009

National site name: Hunter Island Group

Central coordinates: Latitude: -40.4793, Longitude: 144.8290

System: marine, terrestrial

Elevation (m): 0 to 237

Area of KBA (km²): 147.50823

Protected area coverage (%): 98.54

KBA classification: Global

Legacy site: Yes

Site details

Site description: The Hunter Island IBA consists of numerous, varied islands off north-west Tasmania. It abuts the Robbins Passage and Boullanger Bay IBA to the south, which includes the seabird islands of Petrel Islands and Walker Island. Three Hummock Island (6967 ha) has a coastline of exposed granite outcrops interspersed with 10km of sandy beaches and dune areas. Eastern hills border a broad, flat plain in the centre of the island, and it gets its name from the highest three (100m, 160m and 237m). A series of swamps and lagoons have resulted from extensive dune systems blocking drainage from the plain, and thick vegetation with trees as high as 35m is mixed with abandoned pastoral land. Habitat types at Hunter Island (7330 ha) comprise a mix of cattle-grazed paddocks, swamps, heathland, thick scrub and woodland copses, and infrastructure on these larger islands includes settlements, lighthouses and airstrips. The whole of Hunter is taken as an IBA, partly because of its importance for Orange-bellied Parrot. Steep Island (22 ha) west of Hunter is a steep grassy island with very large numbers of shearwaters and penguins. Bird Island (44 ha) south-west of Hunter is rocky and scrubby but has large numbers of penguins and Sooty Oystercatchers. Stack Island (24 ha) is scrubby with Pacific Gull nesting around the edge. Penguin Islet (3 ha) has the largest diversity of breeding seabirds in Tasmania. The somewhat peripheral Trefoil Island (115 ha) is included here, though it could equally well be an IBA in its own right. Trefoil Island is steep and grassy with 698,262 pairs of Short-tailed Shearwater and 40 pairs of Pacific Gull. Little Trefoil (0.6 ha) has 15 pairs Pacific Gull. The spectacular Doughboys (12 ha) have sloping supratidal platforms, vertical cliffs and steeply sloping grassy hills. Other important islets to the south, extending to the far north-west of the Tasmanian mainland, include Henderson, Harbour and Murkay Islets, with 46 pairs of Pacific Gull.

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 the following species suggest that the whole IBA may support more than 1% of the world population. Common Diving-Petrel (IBA threshold is 70,000 pairs): 23000-25000 pairs on Steep Island and 7000-8000 pairs on the Doughboys. Little Penguin (10,000 pairs): 2000-3000 pairs on Steep Island, 3000 pairs on Bird Island, 2059 pairs on Three Hummock Island and 500 pairs on Trefoil Island. 1000 pairs White-faced Storm-Petrel reported on Penguin Islet. Records of Lewin's Rail at Trefoil and Hunter Islands are noteworthy, when the decline of the endemic Tasmanian race brachipus gives cause for serious concern. Nine pairs of Australian Pelican have bred on Penguin Islet; the islet is one of the few breeding sites for this species in Tasmania. Brothers et al. (2001) recorded small numbers of Fairy Tern, consisting of one pair feeding at Bird Island, one pair breeding at Stack Island and two individuals in flight over Seacrow Islet; and also small numbers of Hooded Plover on Stack Island (pairs and parties of up to five), Three Hummock Island (14 breeding pairs) and Seacrow Islet. Non-bird biodiversity: Metallic Skink, White's Skink, Water Rat and Tiger Snake (irresponsibly introduced at Trefoil and Steep Islands, where potentially devastating to breeding seabirds).

Other site values: The Doughboys, Three Hummock and Penguin Islands are Nature Reserves; Steep Island and Trefoil Island are owned by the Tasmanian Aboriginal community; Hunter Island is a Conservation Area with a private pastoral lease; Stack Island, Bird Island and others are Game Reserves. Permission for access must be sought from the owners or DPIW.

Habitats

Land use: nature conservation and research | rangeland/pastureland

IUCN Habitat	Coverage %	Habitat detail
Marine Coastal/Supratidal	19
Artificial - Terrestrial	37
Grassland	4
Forest	4
Shrubland	37

Threats

Summary of threats to biodiversity at KBA: Cattle grazing needs to be regulated to maintain habitat suitability for Orange-bellied Parrot and seabirds. The impacts of long-line and net fishing, feral predators and invasive alien plants should be investigated. Some islands need up-graded protected area status.

Threat level 1	Threat level 2	Threat level 3	Timing
Agriculture & aquaculture	Livestock farming & ranching	Agro-industry grazing, ranching or farming	Ongoing
Biological resource use	Hunting & collecting terrestrial animals	Intentional use (species being assessed is the target)	Ongoing
Biological resource use	Fishing & harvesting aquatic resources	Unintentional effects: large scale (species being assessed is not the target) [harvest]	Ongoing
Natural system modifications	Fire & fire suppression	Trend Unknown/Unrecorded	Ongoing
Invasive & other problematic species, genes & diseases	Invasive non-native/alien species/diseases	Named species	Ongoing

Additional information

References: Brothers, N., Pemberton, D., Pryor, H. and Halley, V. (2001) Tasmania's Offshore Islands: seabirds and other natural features. Tasmanian Museum and Art Gallery: Hobart. Hocking, G. (2007) Personal communication on Cape Barren Geese at Three Hummock and Hunter Islands, 1989-2007. Skira, I.J., Brothers, N.P. and Pemberton, D. (1996) Distribution, abundance and conservation status of Short-tailed Shearwaters Puffinus tenuirostris in Tasmania. Marine Ornithology 24: 1-14.