一項(xiàng)最新研究顯示,，在約8000年前的一次氣候變化過(guò)程中,，南極象海豹獲得了一塊新的棲息地，而約1000年前氣候再次變化時(shí),，這一大型棲息地上的象海豹幾乎完全滅絕,。
英國(guó)達(dá)勒姆大學(xué)10日發(fā)布新聞公報(bào)說(shuō)，由該校研究人員領(lǐng)頭的一個(gè)國(guó)際科研小組利用基因技術(shù),，分析了在南極維多利亞沿岸發(fā)現(xiàn)的一些象海豹?dú)堄辔?。結(jié)果發(fā)現(xiàn)，樣本中的DNA（脫氧核糖核酸）具有高度多樣性,，說(shuō)明這一地區(qū)曾是一個(gè)相當(dāng)大規(guī)模的象海豹棲息地,。
但現(xiàn)在這一地區(qū)并沒(méi)有象海豹生存，最近的象海豹棲息地離這里足有2500公里,。
進(jìn)一步分析顯示,，這是因?yàn)榧s8000年前的一次氣候變化使得南極冰蓋縮小，形成了這塊棲息地,。由于環(huán)境良好,、食物充足，象海豹很快遷徙到這里并形成一個(gè)大規(guī)模種群,。但是,，約1000年前，氣候再次變化,，冰蓋“卷土重來(lái)”,，除少數(shù)象海豹回到原有家園外，這一地區(qū)的大多數(shù)象海豹都隨環(huán)境變化而滅絕,。
研究人員說(shuō),，這說(shuō)明了氣候變化對(duì)生物種群的深遠(yuǎn)影響，也為如何應(yīng)對(duì)未來(lái)可能的氣候變化提供了參考,。這一研究報(bào)告發(fā)表在最新一期美國(guó)《公共科學(xué)圖書(shū)館·遺傳學(xué)》月刊上,。
象海豹是大型動(dòng)物之一，雄性象海豹體重可達(dá)幾千公斤,。象海豹可長(zhǎng)時(shí)間生活在海洋中,，但在換毛,、繁殖等時(shí)期需要移至陸地。（生物谷Bioon.com）
生物谷推薦原始出處：
PLoS Genet 5(7): e1000554. doi:10.1371/journal.pgen.1000554
Rapid Response of a Marine Mammal Species to Holocene Climate and Habitat Change
Mark de Bruyn1¤*, Brenda L. Hall2, Lucas F. Chauke3, Carlo Baroni4, Paul L. Koch5, A. Rus Hoelzel1*
1 School of Biological Sciences, University of Durham, Durham, United Kingdom, 2 Climate Change Institute and Department of Earth Sciences, University of Maine, Orono, Maine, United States of America, 3 Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa, 4 Dipartimento di Scienze della Terra, Università di Pisa, Pisa, Italy, 5 Department of Earth and Planetary Sciences, University of California, Santa Cruz, California, United States of America
Environmental change drives demographic and evolutionary processes that determine diversity within and among species. Tracking these processes during periods of change reveals mechanisms for the establishment of populations and provides predictive data on response to potential future impacts, including those caused by anthropogenic climate change. Here we show how a highly mobile marine species responded to the gain and loss of new breeding habitat. Southern elephant seal, Mirounga leonina, remains were found along the Victoria Land Coast (VLC) in the Ross Sea, Antarctica, 2,500 km from the nearest extant breeding site on Macquarie Island (MQ). This habitat was released after retreat of the grounded ice sheet in the Ross Sea Embayment 7,500–8,000 cal YBP, and is within the range of modern foraging excursions from the MQ colony. Using ancient mtDNA and coalescent models, we tracked the population dynamics of the now extinct VLC colony and the connectivity between this and extant breeding sites. We found a clear expansion signal in the VLC population ~8,000 YBP, followed by directional migration away from VLC and the loss of diversity at ~1,000 YBP, when sea ice is thought to have expanded. Our data suggest that VLC seals came initially from MQ and that some returned there once the VLC habitat was lost, ~7,000 years later. We track the founder-extinction dynamics of a population from inception to extinction in the context of Holocene climate change and present evidence that an unexpectedly diverse, differentiated breeding population was founded from a distant source population soon after habitat became available.
