Chalky, Big Green and Badger Island Groups (23987)
Australia, Australasia
Site overview
KBA status: confirmed
Global KBA criteria: A1b, B1, D1a
Year of last assessment: 2009
National site name: Chalky, Big Green and Badger Island Groups
Central coordinates: Latitude: -40.2337, Longitude: 147.8838
System: marine, terrestrial
Elevation (m): 0 to 30
Area of KBA (km2): 27.91759
Protected area coverage (%): 78.77
KBA classification: Global
Legacy site: Yes
Site details
Site description: This IBA extends from the Pasco Islands off north-west Flinders Island south through the Chalky, Big Green and East Kangaroo group to the Badger group off south-west Flinders Island, in the Bass Strait. It includes North, Middle and South Pasco Islands (28, 8 and 21 ha; Crown Land; Pacific Gull), Marriot Reef (3.4ha; Crown Land; Pacific Gull), Wybalenna Island (16 ha; Conservation Area; Pacific Gull), Low Islets (0.8 ha; Crown Land; Pacific Gull) but not Prime Seal Island (which could support large numbers of nesting shearwater if grazing pressure was reduced), Chalky Island (41 ha; Conservation Area; geese and seabirds), Little Chalky Island (5 ha; crown land; Pacific Gull), Mile Island (4 ha; Conservation Area; Pacific Gull), Isabella Island (11 ha; Nature Reserve; Pacific Gull), Big Green Island (122 ha; Nature Reserve; Cape Barren Geese), East Kangaroo (157 ha; Nature Reserve; Cape Barren Geese); Mount Chappell Island (323 ha; private; large shearwater colony; other birds not counted), North West Mount Chappell Islet (0.7 ha; 35 pairs Pacific Gull), Little Goose Island (3.6 ha; Nature Reserve; many Pacific Gull), Badger Island (1243 ha; private; Cape Barren Geese), Little Badger Island (2.5 ha; Nature reserve; Black-faced Cormorant colony), Goose Island (109 ha; Conservation Area; many seabirds) and Beagle Island (1 ha; Nature Reserve; Pacific Gull and cormorant). The Pasco Islands are small rocky granitic islands with some sheep grazing. Marriot Reef is a small islet group of low granitic islands. Chalky Island is a granite island with dolerite dykes and limestone outcrops. Vegetation varies across the island with Rhagodia candolleana and Tetragonia implexicoma dominating the south of the island, Poa poiformis and Rhagodia candolleana dominating the centre and halophytic shrubs growing in the northern area. Little Chalky Island is a small, flat granite island dominated by Poa poiformis, Rhagodia candolleana and Atriplex cinerea. Mile Island is dominated by Atriplex cinerea and Tetragonia implexicoma in the southern region and bare granite in the north along with Poa poiformis. Isabella Island is a low, flat, circular island dominated by Poa poiformis, Rhagodia candolleana and Acaena sp. Big Green is grazed and has two farmhouses and an airstrip. East Kangaroo is mostly abandoned sheep pasture dominated by introduced pasture and thistles. Mount Chappell Island is farmed, has been burnt and ploughed, and suffers from many introduced species including cats. Goose Island has a lighthouse and has been grazed; it is now dominated by grass, succulent forbs and African boxthorn. Badger Island is a large grazed island which suffers from grazing, burning, introduced species and depredation by Tasmanian Devils. Little Badger Island is a small gently sloping grassy island. Mount Chapell and Badger are Indigenous Protected Areas. The boundaries of this IBA are somewhat arbitrary but all the islands are important for their geese and/or seabirds.
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: Other birds have not been documented for this IBA. Non-bird biodiversity: Metallic Skink, White-lipped Whip Snake, White's Skink and Tiger Snake.
Other site values: Tasmanian State Government and private land owners. Permission should be sought from DPIW before visiting protected islands. Permission should be sought from private land-owners before visiting private islands.
Habitats
Land use: nature conservation and research | not utilised | rangeland/pastureland
| IUCN Habitat | Coverage % | Habitat detail |
|---|---|---|
| Shrubland | 4 | |
| Artificial - Terrestrial | 38 | |
| Grassland | 38 | |
| Marine Coastal/Supratidal | 19 |
Threats
Summary of threats to biodiversity at KBA: Eradications of cats, mice and other invasive species should be investigated and implemented. The impact of human visitors on nesting seabirds and their habitat should be investigated. Grazing and other land-uses should be managed to minimise the introduction and spread of invasive alien species.
| 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 | Fishing & harvesting aquatic resources | Unintentional effects: large scale (species being assessed is not the target) [harvest] | Ongoing |
| Invasive & other problematic species, genes & diseases | Invasive non-native/alien species/diseases | Named species | Ongoing |
| Human intrusions & disturbance | Recreational activities | Ongoing |
Additional information
References: Brothers, N.P. and Skira, I.J. (2000) Little Chalky Island, Furneaux Group, Tasmania. Corella 24: 47-48. Brothers, N., Pemberton, D., Pryor, H. & Halley, V. (2001) Tasmania's Offshore Islands: seabirds and other natural features. Tasmanian Museum and Art gallery: Hobart. Higgins, P.J. and Davies, P.J.J.F. (1996) Handbook of Australian, New Zealand and Antarctic Birds, Volume 3. Oxford University Press: Melbourne. Skira, I.J., Brothers, N.P. and Pemberton, D. (1996) Distribution, abundance and conservation status of Short-tailed Shearwaters Puffinus tenuirostris in Tasmania, Australia. Marine Ornithology 24: 1-14.
Contributors: The nomination was prepared by Birds Australia.