Ice-age megafauna in Arctic Alaska: extinction, invasion, survival
Ice-age megafauna in Arctic Alaska: extinction, invasion, survival
复制标题
DOI：
10.1016/j.quascirev.2013.03.015
复制
发表时间：
2013-06
影响因子：
4
通讯作者：
D. Mann;P. Groves;M. Kunz;R. Reanier;B. Gaglioti
中科院分区：
文献类型：
--
作者：
D. Mann;P. Groves;M. Kunz;R. Reanier;B. Gaglioti
生活在阿拉斯加北极的陆地大型哺乳动物动物群的彻底重组发生在14,000到10,000年前最后一个冰河时代的末期。草原野牛、马和猛犸象灭绝，驼鹿和人类入侵，而麝香和驯鹿继续存在。冰河时代的大型动物种类更加多样，可能包含的个体动物比今天生活在该地区的动物多6倍。上一次冰河时期的大型动物生物量可能是现在的30倍。就个体数量而言，马是优势物种。狮子、短面熊、狼，可能还有灰熊组成了捕食者/清道夫协会。到目前为止发现的最年轻的猛犸象生活在大约13,800年前，而马和野牛一直生活在北坡，直到至少12,500年前年轻的仙女座寒冷时期。大约13,500年前，第一批人到达了北坡。骨骼同位素测量和脚部负重特征表明，大型动物群的生态位沿着水分梯度被分离，幸存的物种(麝香和驯鹿)利用植被镶嵌中较温暖和较潮湿的部分。随着冰河时代的结束，水分梯度转移并消除了旱地放牧物种(野牛、马、猛犸象)所利用的栖息地。这一变化的直接原因是区域沼泽化、有机土层和泥炭的扩散。阿拉斯加北极地区更新世末期的灭绝代表的是局部灭绝，而不是全球灭绝，因为在那里消失的大型动物物种一直持续到其他地方的更晚时间。狩猎似乎不太可能是这些灭绝的原因，但不能排除这是对大型动物种群的最后一击，当人类到达该地区时，这些种群已经在功能上灭绝了。
Radical restructuring of the terrestrial, large mammal fauna living in arctic Alaska occurred between 14,000 and 10,000 years ago at the end of the last ice age. Steppe bison, horse, and woolly mammoth became extinct, moose and humans invaded, while muskox and caribou persisted. The ice age megafauna was more diverse in species and possibly contained 6× more individual animals than live in the region today. Megafaunal biomass during the last ice age may have been 30× greater than present. Horse was the dominant species in terms of number of individuals. Lions, short-faced bears, wolves, and possibly grizzly bears comprised the predator/scavenger guild. The youngest mammoth so far discovered lived ca 13,800 years ago, while horses and bison persisted on the North Slope until at least 12,500 years ago during the Younger Dryas cold interval. The first people arrived on the North Slope ca 13,500 years ago. Bone-isotope measurements and foot-loading characteristics suggest megafaunal niches were segregated along a moisture gradient, with the surviving species (muskox and caribou) utilizing the warmer and moister portions of the vegetation mosaic. As the ice age ended, the moisture gradient shifted and eliminated habitats utilized by the dryland, grazing species (bison, horse, mammoth). The proximate cause for this change was regional paludification, the spread of organic soil horizons and peat. End-Pleistocene extinctions in arctic Alaska represent local, not global extinctions since the megafaunal species lost there persisted to later times elsewhere. Hunting seems unlikely as the cause of these extinctions, but it cannot be ruled out as the final blow to megafaunal populations that were already functionally extinct by the time humans arrived in the region.