Pedra Branca (23959)
Australia, Australasia

Site overview

KBA status: confirmed

Global KBA criteria: D1a

Year of last assessment: 2009

National site name: Pedra Branca

Central coordinates: Latitude: -43.8580, Longitude: 146.9803

System: marine, terrestrial

Elevation (m): 0 to 60

Area of KBA (km²): 0.01692

Protected area coverage (%): 73.82

KBA classification: Global

Legacy site: Yes

Site details

Site description: Pedra Branca is the southernmost island in Australia, lying 26 km south of Whale Head in the Southwest National Park. The IBA also includes the nearby small Eddystone and Sidmouth Rocks. Pedra Branca is a rocky island with steep slopes on its eastern and western sides which rise to a north-south aligned central ridge. The key seabird species nest on tiered rock platforms and sparsely-vegetated cliff ledges of the island. Nest mounds of 270 pairs of Shy Albatross are interspersed with nests of Australasian Gannets, numbers of which have increased by approximately 7% per year from about 1000 pairs in 1978 to a congested 3317 pairs in 1995. Other seabirds are restricted to sites on unsuitable lower ledges that are affected by sea and weather conditions. Australasian Gannet numbers at nearby Eddystone Rock have also increased in recent decades from 20 pairs in 1947 to 189 pairs in 1998, when all suitable habitat was occupied.

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 Prion, Pacific Gull, Kelp Gull and Black-faced Cormorant breed in very small numbers. Silver Gull numbers increased from 10 pairs in 1978 to 52 pairs in 1990, with most nests located on rocks and overhangs where Pedra Branca Skinks are most abundant. Non-bird biodiversity: Silver Gulls are believed to be responsible for declining numbers of the endemic Pedra Branca Skink, of which fewer than 400 individuals survive. Up to 500 Australian Fur Seals are regular and New Zealand Fur Seals visit occasionally. Sarcocornia quinqueflora, which is sparse and confined to rock cracks, is the only plant species recorded for the island.

Other site values: Land is owned by the Tasmanian State Government and managed by the Department of Primary Industries and Water. Public access is prohibited to protect breeding seabirds.

Habitats

Land use: nature conservation and research (100%)

IUCN Habitat	Coverage %	Habitat detail
Marine Coastal/Supratidal	100

Threats

Summary of threats to biodiversity at KBA: Maintain current protection protocols for seabird breeding colonies, under which unregulated visits are prohibited. Further measures to reduce by-catch of seabirds by long-line fisheries are needed to protect Shy Albatrosses at sea.

Threat level 1	Threat level 2	Threat level 3	Timing
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	Problematic native species/diseases	Named species	Ongoing

Additional information

References: Bunce, A., Norman, F.I., Brothers, N. and Gales, R. (2002) Long-term trends in the Australasian Gannet (Morus serrator) population in Australia: the effect of climate change and commercial fisheries. Marine Biology 14: 263-269. BirdLife International (2007) Species factsheet: Thalassarche cauta. Downloaded from http://www.birdlife.org on 29/6/2007. 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. Robertson, G.G. and Gales, R.(1998) Albatross Biology and Conservation. Surrey Beatty & Sons Pty Ltd: Chipping Norton, New South Wales. White, G.(1981) Islands of south-west Tasmania. A.T. Sutton & Co. Pty Ltd: Sydney.