Brownson Islands (45239)
Antarctica, Antarctica
Site overview
KBA status: confirmed
Year of last assessment: 2015
National site name: Brownson Islands
Central coordinates: Latitude: -74.1469, Longitude: -103.6326
System: marine, terrestrial
Elevation (m): 0 to 20
Area of KBA (km2): 7.92316
KBA classification: Regional
Legacy site: Yes
Site details
Site description: Brownson Islands are situated approximately 30 km south of the northern extremity of Canisteo Peninsula, which projects into the eastern Amundsen Sea between Ferrero and Cranton Bays on the Walgreen Coast, Marie Byrd Land. The island group comprises four main islands surrounded by numerous smaller islets and rocks. Brownson Islands are largely ice-free in summer and consist of granites cut by thick basaltic dykes (Gohl 2010). Emperor Penguins (Aptenodytes forsteri) breed on fast ice that forms between two small islands separated by ~200 m in the northwest of the group, and Adélie Penguins (Pygoscelis adeliae) breed on an ice free point at the west of the most southerly island of the group The IBA qualifies on the basis of the Emperor Penguin colony present and the concentration of seabirds (in particular Adélie Penguin) and includes the breeding sites and the surrounding marine area extending between these islands. There are no research stations nearby. The closest permanent stations are Rothera (GBR) and San Martín (ARG), located approximately 1450 km to the northeast in Marguerite Bay, Antarctic Peninsula.
Rationale for qualifying as KBA: This site qualifies as a Key Biodiversity Area of international significance that was identified using previously established criteria and thresholds for the identification of Important Bird and Biodiversity Areas (IBAs) and for which available data indicate that it does not meet global KBA criteria and thresholds set out in the Global Standard.
Additional biodiversity: Analysis of a satellite image acquired 18 Nov 2009 (Fretwell et al. 2012) indicated that approximately 5732 Emperor Penguins were present at the colony, although image quality was rated as Poor. The colony was identified for the first time by Fretwell et al. (2012). Approximately 15 962 breeding pairs (95% CI: 9438, 26 013) of Adélie Penguin were present on the ice free point on the most southerly of the Brownson Islands in December 2011, as estimated from satellite imagery (Lynch & LaRue 2014). No other birds are known to breed in the area. Non-bird biodiversity: None known.
Delineation rationale: Shortest perimeter around islands and/or ice-free areas >5km2.
Threats
Summary of threats to biodiversity at KBA: None known.
Additional information
References: Fretwell, P.T., LaRue, M.A., Morin P., Kooyman, G.L., Wienecke, B., Ratcliffe, N., Fox, A.J., Fleming, A.H., Porter, C. & Trathan, P.N. 2012. An Emperor Penguin population estimate: The first global, synoptic survey of a species from space. PLoS ONE 7(4): e33751. doi:10.1371/journal.pone.0033751 Gohl, K. (ed.) 2010. The expedition of the Research Vessel “Polarstern” to the Amundsen Sea, Antarctica in 2010. Berichte zur Polar- und Meeresforschung. 617/2010. Lynch, H.J. & LaRue, M.A. 2014. First global census of the Adélie Penguin. The Auk 131(4): 457-66. doi:10.1642/AUK-14-31.1