Rabanus-Wallace M Timothy, Wooller Matthew J, Zazula Grant D, Shute Elen, Jahren A Hope, Kosintsev Pavel, Burns James A, Breen James, Llamas Bastien, Cooper Alan
Australian Centre for Ancient DNA, University of Adelaide, North Terrace, South Australia 5005, Australia.
Alaska Stable Isotope Facility, Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, Alaska 99775, USA.
Nat Ecol Evol. 2017 Apr 18;1(5):125. doi: 10.1038/s41559-017-0125.
The role of environmental change in the late Pleistocene megafaunal extinctions remains a key question, owing in part to uncertainty about landscape changes at continental scales. We investigated the influence of environmental changes on megaherbivores using bone collagen nitrogen isotopes (n = 684, 63 new) as a proxy for moisture levels in the rangelands that sustained late Pleistocene grazers. An increase in landscape moisture in Europe, Siberia and the Americas during the Last Glacial-Interglacial Transition (LGIT; ~25-10 kyr bp) directly affected megaherbivore ecology on four continents, and was associated with a key period of population decline and extinction. In all regions, the period of greatest moisture coincided with regional deglaciation and preceded the widespread formation of wetland environments. Moisture-driven environmental changes appear to have played an important part in the late Quaternary megafaunal extinctions through alteration of environments such as rangelands, which supported a large biomass of specialist grazers. On a continental scale, LGIT moisture changes manifested differently according to regional climate and geography, and the stable presence of grasslands surrounding the central forested belt of Africa during this period helps to explain why proportionally fewer African megafauna became extinct during the late Pleistocene.
晚更新世大型动物灭绝过程中环境变化所起的作用仍是一个关键问题，部分原因在于大陆尺度景观变化存在不确定性。我们利用骨胶原氮同位素（n = 684，新增63个）作为维持晚更新世食草动物的牧场湿度水平的替代指标，研究了环境变化对大型食草动物的影响。末次冰期 - 间冰期过渡阶段（LGIT；约25 - 10 kyr bp）期间，欧洲、西伯利亚和美洲景观湿度增加，直接影响了四大洲的大型食草动物生态，且与种群数量下降和灭绝的关键时期相关。在所有地区，湿度最大的时期与区域冰川消退同时出现，并早于湿地环境的广泛形成。水分驱动的环境变化似乎通过改变牧场等环境，在晚第四纪大型动物灭绝过程中发挥了重要作用，牧场曾支撑着大量特化食草动物的生物量。在大陆尺度上，LGIT湿度变化因区域气候和地理条件而表现各异，这一时期非洲中部森林带周围草原的稳定存在有助于解释为何晚更新世期间非洲大型动物灭绝的比例相对较低。
