Research press release


Scientific Reports

Ecology: Penguin populations picked up during the Little Ice Age



今回、Zhou-Qing Xieたちは、ロス島のケープ・バードで採取された堆積物に含まれていたバイオマーカーを使って、アデリーペンギンのコロニーにおける過去700年間の個体数の推移を推測した。その結果、小氷期の初め、つまり、夏季の気温が、それまでの200年間より摂氏約2度低くなった時期に、この地域がアザラシの生息地からペンギンの生息地に変わり、ペンギンがこの地域の優占種になったことが明らかになった。また、ペンギンの個体数のピークは、紀元前1670~1490年頃であったことも判明した。Xieたちは、海氷の拡大によってペンギンの重要な食料源であるオキアミが豊富に得られる点を指摘し、気候変動に応じた南極のペンギンの個体数の変化は、緯度によって異なっている可能性があると結論付けている。

Reconstruction of the population history of Adelie penguin colonies on Ross Island in the high Antarctic using biomarkers suggests that penguin populations boomed during the Little Ice Age, which took place between 1500 and 1800 AD. The findings, published in Scientific Reports this week, differ from results in other more northerly Antarctic regions, suggesting that different responses to climate change may occur at low and high altitudes in the Antarctic.

Penguin population dynamics can be affected by variations in climatic and environmental factors, such as sea-surface temperature, air temperature, snow cover and food abundance. Previous research has indicated that penguin populations in the maritime Antarctic increased when the climate became warmer and decreased when it became cooler. During cold periods, increased sea ice can prevent beach access by penguins to their colonies, and lack of food can also be a problem.

Zhou-Qing Xie and colleagues used biomarkers in sediment collected at Cape Bird on Ross Island to reconstruct population changes in Adelie penguin colonies over the past 700 years. They show that the region transformed from a seal to a penguin habitat at the start of the Little Ice Age when the summer temperature was around 2oC colder than during the previous 200 years, and penguins then became the dominant species. Penguin populations peaked between around 1490 and 1670 AD, the results show. The authors note that extended sea ice can provide abundant krill - a key food source for penguins. They conclude that penguin populations in different altitudes in the Antarctic may undergo different changes in response to climate change.

doi: 10.1038/srep02472


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