Variability in krill biomass links harvesting and climate warming to penguin population changes in Antarctica
Top Cited Papers
- 11 April 2011
- journal article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 108 (18), 7625-7628
- https://doi.org/10.1073/pnas.1016560108
Abstract
The West Antarctic Peninsula (WAP) and adjacent Scotia Sea support abundant wildlife populations, many of which were nearly extirpated by humans. This region is also among the fastest-warming areas on the planet, with 5-6 °C increases in mean winter air temperatures and associated decreases in winter sea-ice cover. These biological and physical perturbations have affected the ecosystem profoundly. One hypothesis guiding ecological interpretations of changes in top predator populations in this region, the "sea-ice hypothesis," proposes that reductions in winter sea ice have led directly to declines in "ice-loving" species by decreasing their winter habitat, while populations of "ice-avoiding" species have increased. However, 30 y of field studies and recent surveys of penguins throughout the WAP and Scotia Sea demonstrate this mechanism is not controlling penguin populations; populations of both ice-loving Adélie and ice-avoiding chinstrap penguins have declined significantly. We argue in favor of an alternative, more robust hypothesis that attributes both increases and decreases in penguin populations to changes in the abundance of their main prey, Antarctic krill. Unlike many other predators in this region, Adélie and chinstrap penguins were never directly harvested by man; thus, their population trajectories track the impacts of biological and environmental changes in this ecosystem. Linking trends in penguin abundance with trends in krill biomass explains why populations of Adélie and chinstrap penguins increased after competitors (fur seals, baleen whales, and some fishes) were nearly extirpated in the 19th to mid-20th centuries and currently are decreasing in response to climate change.Keywords
This publication has 34 references indexed in Scilit:
- Variations in the biomass of Antarctic krill (Euphausia superba) around the South Shetland Islands, 1996–2006ICES Journal of Marine Science, 2008
- Ecological Responses to Climate Change on the Antarctic PeninsulaAmerican Scientist, 2008
- Abrupt recent shift in δ 13 C and δ 15 N values in Adélie penguin eggshell in AntarcticaProceedings of the National Academy of Sciences, 2007
- Divergent responses of Pygoscelis penguins reveal a common environmental driverOecologia, 2007
- Biomass and energy transfer to baleen whales in the South Atlantic sector of the Southern OceanDeep Sea Research Part II: Topical Studies in Oceanography, 2004
- Foraging modes of chinstrap penguins:contrasts between day and nightMarine Ecology Progress Series, 1998
- Ecological Segregation of Adelie, Gentoo, and Chinstrap Penguins at King George Island, AntarcticaEcology, 1987
- The food and feeding ecology of Adélie penguins (Pygoscelis adeliae) and Chinstrap penguins (P. antarctica) at Signy Island, South Orkney IslandsJournal of Zoology, 1985
- Seals and whales of the Southern OceanPhilosophical Transactions of the Royal Society of London. B, Biological Sciences, 1977
- Fur Seals Breeding in the Falkland Islands DependenciesNature, 1961