Forsyth, Passage and Gull Islands (23914)
Australia, Australasia

Site overview

KBA status: confirmed

Global KBA criteria: B1

Year of last assessment: 2009

National site name: Forsyth, Passage and Gull Islands

Central coordinates: Latitude: -40.5063, Longitude: 148.3315

System: marine, terrestrial

Elevation (m): 0 to 27

Area of KBA (km²): 4.27135

Protected area coverage (%): 99.33

KBA classification: Global

Legacy site: Yes

Site details

Site description: Forsyth, Passage and Gull Islands are located south of Cape Barren Island and east of Clarke Island, in the Bass Strait. Forsyth and Passage are neighbouring islands whereas Gull is some 15 km to the east. Passage Island has been heavily grazed in the past, particularly in the north. It is an elongate island with sandy soils and low vegetation. A dolerite band with broken granite slabs stretches up the east side of the island. The island has its own airstrip and also includes a hut and shed. Heavy grazing and rabbits have had an effect on the vegetation and seabird habitat. The southern end is more susceptible to disturbance because of sandy soils and shearwater colonies. Forsyth Island is oriented north to south, is elongate and scrub covered with sandy beaches against granite slabs and rocks. There is a central ridge with gently undulating vegetated dunes which run east to west. The soil is very sandy and there is sand blow in the central region. Fire could affect the vegetation and therefore the stability of the dunes which many of the birds rely on. Gull Island is a 8.5 ha granite island with shallow sandy soils. The shoreline is made up of granite slabs reaching 20m from the sea and many inland areas are composed of bare rocks and boulders in between the vegetation (Brothers et al. 2001).

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: Fairy Terns have nested on Gull Island but not consistently (R. Alderman & R. Gales in litt. 2008). Other birds of significance found on Passage and Forsyth Islands include Short-tailed Shearwaters with 2230 burrows on Passage Island and 6400 burrows on Forsyth Island (Skira et al. 1996), Pacific Gulls (three pairs on Passage, seven pairs on Forsyth and three pairs on Gull), Sooty Oystercatchers (10 pairs on Passage, four pairs on Forsyth and six pairs on Gull) and White-faced Storm-Petrel (4320 pairs on Gull and 100 pairs on Forsyth; Brothers et al. 2001). Non-bird biodiversity: Blue-tongue Lizard and Tiger Snake were found on Forsyth Island while White's Skink and Metallic Skink were found on Passage Island. Forsyth Island recorded House Mouse, a trapped rat and a swamp rat; no native mammals were found on Passage Island, however, there was a rat, rabbit (numerous), cattle (30) and house mouse. Vegetation found on Forsyth Island includes Poa poiformis, Senecio sp., Stipa, Tetragonia sp., Carpobrotus rossii, Oleania axillaris, Ozothamnus turbinatus, Leptospermum laevigatum and Myoporum insulare. Passage Island supports such vegetation as Acacia sophorae, Callitris rhomboidea, Allocasuarina verticillata, Leptospermum laevigatum and Melaleuca ericifolia (Brothers et al. 2001).

Other site values: Tasmanian and Federal Governments. Advice on visiting these vulnerable islands should be sought from DPIW.

Habitats

Land use: nature conservation and research | not utilised | rangeland/pastureland

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

Threats

Summary of threats to biodiversity at KBA: Grazing of cattle should be kept to a minimum and restricted to the north of Passage Island away from the delicate soils in the south. The status of native and introduced small mammals on both islands needs to be ascertained and then alien rats, mice and rabbits should be eradicated.

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., Pemberton, D., Pryor, H. & Halley, V. (2001) Tasmania's Offshore Islands: seabirds and other natural features. Tasmanian Museum and Art gallery: Hobart. Skira, I.J., Brothers, N.P. & Pemberton, D. (1996) Distribution, abundance and conservation status of Short-tailed Shearwaters Puffinus tenuirostris in Tasmania, Australia. Marine Ornithology 24: 1-14.