北極の生息地喪失の危機(Climate crisis pressures the ‘Arctic giant’: Habitats risk disappearing completely)

ad

2025-06-04 コペンハーゲン大学(UCPH)

北極の生息地喪失の危機(Climate crisis pressures the ‘Arctic giant’: Habitats risk disappearing completely)

コペンハーゲン大学の研究チームは、地球温暖化が北極圏のシロナガスクジラ(bowhead whale)の生息地に深刻な影響を及ぼしていることを明らかにしました。研究によれば、2100年までに同種の生息域が最大75%減少する可能性があり、特にオホーツク海の個体群は2060年までに夏季の適応環境を完全に失うと予測されています。シロナガスクジラは、過去1万1700年間、夏季に15〜30%の海氷が存在する地域を好んで生息してきましたが、近年の急速な海氷減少により、これらの環境が失われつつあります。研究チームは、化石記録や捕鯨船の航海日誌、コンピューターモデルを用いて、過去から現在までの生息地の変遷を分析しました。この知見は、将来の保全戦略の立案において重要な指針となると期待されています。

<関連情報>

21世紀の海氷減少は、ホッキョククジラの11,700年にわたる安定した生息地を一変させるだろう 21st Century Sea Ice Loss Will Upend 11,700 Years of Stable Habitat for Bowhead Whales

Nicholas A. Freymueller, Eline D. Lorenzen, Stuart C. Brown, Carsten Rahbek, Damien A. Fordham

Ecology and Evolution  Published: 20 May 2025

DOI:https://doi.org/10.1002/ece3.71377

Details are in the caption following the image

ABSTRACT

Bowhead whales (Balaena mysticetus) are strongly associated with Arctic sea ice during their crucial summer feeding period. However, anthropogenic climate change is causing a decline in sea ice concentrations, threatening bowhead whale suitable habitat. To characterise the long-term affinity of bowhead whales to sea ice across the Holocene and project the response of populations to 21st century climate change, we built ecological models of occurrence–environmental relationships using distribution-wide fossil, historical, and contemporary records. We found that throughout the Holocene, bowhead whale habitat suitability was consistently highest in summer average sea ice concentrations of 15%–30%. Projecting these models forward in time to 2100 ce showed that 21st century climate change is set to erode these critical sea ice conditions, resulting in the circumpolar range of bowhead whales contracting by up to 75%. We project that during this century, habitat suitability will decline in all four management populations of bowhead whales by at least 52%, with suitable habitat predicted to vanish completely in the Sea of Okhotsk. It is likely that most viable habitat for bowhead whales will exist outside their current distribution by the end of the century, directly impacting conservation policies. Our results further highlight the vulnerability of Arctic marine endemics in a warming world, showcasing how knowledge of the past can strengthen predictions of species future vulnerability to rapid ocean warming.

1903自然環境保全
ad
ad
Follow
ad
タイトルとURLをコピーしました