A gloomy future for light-bellied brent geese in Tusenøyane, Svalbard, under a changing predator regime
The endangered population of light-bellied brent geese (Branta bernicla hrota) breeding in Svalbard and north-east Greenland used to have its core breeding area in the archipelago of Tusenøyane in south-east Svalbard. Studies carried out during 1987–1991 showed that the Tusenøyane population was subject to heavy egg predation by polar bears and, in one year, Arctic foxes. Revisiting some key nesting islands in August 2018, we found few nests used by brent geese and no families. The high density of common scurvygrass (Cochlearia officinalis), a food favoured by brent geese and therefore formerly depleted by them, indicates that the geese have been absent for some time. Among other bird species, such as barnacle goose and common eider, very few young were observed as well. As potential predators, polar bears, or signs of their recent presence, were observed on most islands, and great skuas occurred on almost all islands, with 60 individuals on Lurøya, formerly an important island for geese. In contrast, only a single pair of great skuas was observed 30 years ago. The observations suggest that recent expansion of great skuas in the North Atlantic, including Svalbard, has led to a novel extreme predation pressure, additional to that caused by mammalian predators. Despite the loss of Tusenøyane as a breeding ground, the population of brent geese has increased in recent decades; so we can infer that the population now recruits from remote but mainly unknown breeding grounds.
Anker-Nilssen T., Barrett R.T., Bustnes J.O., Erikstad K.E., Fauchald P., Lorentsen S.H., Steen H., Strøm H., Systad G.H. & Tveraa T. 2007. SEAPOP studies in the Lofoten and Barents Sea area in 2006. NINA Report 249. Trondheim: Norwegian Institute of Nature Research. Accessed on the internet at https://munin.uit.no/bitstream/handle/10037/11174/article.pdf?sequence=2 on 15 December 2018
Bayes J.C., Dawson M.J. & Potts G.R. 1964. The food and feeding behaviour of the great skua in the Faroes. Bird Study 11, 272–279, https://doi.org/10.1080/00063656409476077.
Boertmann D., Olsen K. & Nielsen R.D. 2015. Geese in northeast and north Greenland as recorded on aerial surveys in 2008 and 2009. Dansk Ornitologisk Forenings Tidsskrift 109, 206–217.
Bregnballe T. & Madsen J. 1990. Post-hatching behaviour of light-bellied brent geese Branta bernicla hrota. Wildfowl 41, 27–34.
Clausen P. & Craggs A. 2018. K2. East Atlantic (Greenland/Svalbard) light-bellied brent Branta bernicla hrota. In A.D. Fox & J.O. Leafloor (eds.): A global audit of the status and trends of Arctic and Northern Hemisphere goose populations. (Component 2: population accounts.) Pp. 90–92. Akureyri: Conservation of Arctic Flora and Fauna.
Clausen P., Green M. & Alerstam T. 2003. Energy limitations for spring migration and breeding: the case of brent geese Branta bernicla tracked by satellite telemetry to Svalbard and Greenland. Oikos 103, 426–445, https://doi.org/10.1034/j.1600-0706.2003.12340.x.
Fox A.D. & Leafloor J. (eds.) 2018. A global audit of the status and trends of Arctic and Northern Hemisphere goose populations. Akuryri: Conservation of Arctic Flora and Fauna.
Gavrilo M.V. 2013. Modern status of the great skua Catharacta skua in the north eastern Barents Sea. The Russian Journal of Ornithology 22, 1779–1784.
Henriksen S. & Hilmo O. (eds.) 2015. Norsk rødliste for arter 2015. (Norwegian Red List for species 2015.) Norwegian Biodiversity Information Centre. Accessed on the internet at https://www.artsdatabanken.no/Files/13973/Norsk_r_dliste_for_arter_2015_(PDF) on 15 December 2018
Heubeck M., Mellor R.M. & Harvey P.V. 1997. Changes in the breeding distribution and numbers of kittiwakes Rissa tridactyla around Unst, Shetland, and the presumed role of predation by great skuas Catharacta skua. Seabird 19, 12–21.
Jacubas D, Iliszko L.M., Strøm H., Helgason H.H. & Stempniewicz L. 2018. Flexibility of foraging strategies of the great skua Stercorarius skua breeding in the largest colony in the Barents Sea region. Frontiers in Zoology 15, article no. 9. https://doi.org/10.1186/s12983-018-0257-x.
Madsen J. 1987. Status and management of goose populations in Europe, with special reference to populations resting and breeding in Denmark. Danish Review of Game Biology 12(4). Rønde, Denmark: Game Biology Station.
Madsen J., Bregnballe T., Frikke J. & Kristensen J.B. 1998. Correlates of predator abundance with snow and ice conditions and their role in determining timing of nesting and breeding success in Svalbard light-bellied brent geese Branta bernicla hrota. Norsk Polarinstitutt Skrifter 200, 221–234.
Madsen J., Bregnballe T. & Hastrup A. 1992. Impact of the Arctic fox Alopex lagopus on nesting success of geese in southeast Svalbard, 1989. Polar Research 11, 35–39, https://doi.org/10.3402/polar.v11i2.6715
Madsen J., Bregnballe T. & Mehlum F. 1989. Study of the breeding ecology and behaviour of the Svalbard population of light-bellied brent goose Branta bernicla hrota. Polar Research 7, 1–21, https://doi.org/10.1111/j.1751-8369.1989.tb00600.x.
Mitchell I., Newton S.F., Ratcliffe N. & Dunn T.E. (eds.) 2004. Seabird populations of Britain and Ireland: results of the Seabird 2000 census (1998-2002). London: T. and A.D. Poyser.
Oro D. & Furness R.W. 2002. Influences of food availability and predation on survival of kittiwakes. Ecology 83, 2516–2528, https://doi.org/10.1890/0012-9658(2002)083[2516:iofaap]2.0.co;2.
Persen E. 1986. The Svalbard brent goose Branta bernicla population still threatened. Vår Fuglefauna 9, 173–176.
Pokrovskaya I.V. 2016. The great skua Catharacta skua: continued expansion in the Eurasian Arctic. The Russian Journal of Ornithology 25, 1423–1426.
Prop J., Aars J., Bårdsen B.J., Hanssen S.A., Bech C., Bourgeon S., de Fouw J., Gabrielsen G.W., Lang J., Noreen E., Oudman T., Sittler B., Stempniewicz L., Tombre T., Wolters E. & Moe B. 2015. Climate change and the increasing impact of polar bears on bird populations. Frontiers in Ecology and Evolution 3, article 33, https://doi.org/10.3389/fevo.2015.00033.
Rockwell R.F. & Gormezano L.J. 2009. The early bear gets the goose: climate change, polar bears and lesser snow geese in the western Hudson Bay. Polar Biology 32, 539–547, https://doi.org/10.1007/s00300-008-0548-3.
Votier S.C., Crane J.E., Bearhop S., de León A., McSorley C.A., Mínguez E., Mitchell I.P., Parsons M., Phillips R.A. & Furness R. 2006. Nocturnal foraging by great skuas Stercorarius skua: implications for conservation of storm-petrel populations. Journal of Ornithology 147, 405–413, https://doi.org/10.1007/s10336-005-0021-9.
Votier S.C., Furness R.W., Bearhop S., Crane J.E., Caldow R.W., Catry P., Ensor K., Hamer K.C., Hudson A.V., Kalmbach E., Klomp N.I., Pfeiffer S., Phillips R.A., Prieto I. & Thompson D.R. 2004. Changes in fish discard rates and seabird communities. Nature 427, 727–730, https://doi.org/10.1038/nature02315.
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