1.36 million years of Mediterranean forest refugium dynamics in response to glacial-interglacial cycle strength
1.36 million years of Mediterranean forest refugium dynamics in response to glacial-interglacial cycle strength
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DOI：
10.1073/pnas.2026111118
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发表时间：
2021-08-20
影响因子：
11.1
通讯作者：
Sadori, Laura
中科院分区：
文献类型：
--
作者：
Donders, Timme;Panagiotopoulos, Konstantinos;Sadori, Laura
奥赫里德湖（巴尔干半岛西南部）的沉积物记录代表了欧洲最长的连续湖泊档案，可追溯到1.36 Ma。我们重建的植被历史的基础上，花粉分析的深度核心，揭示植被覆盖和森林多样性的变化在冰川间冰期（G-IG）周期和早期盆地的发展。最早的湖泊阶段看到了一个显着不同的组成丰富的孑遗树木类群和少数草药。随后建立一个永久性的草原草本植物协会约1.2马意味着阈值响应水分供应和温度的变化，并逐步调整盆地形态。在早-中更新世过渡期间，G-IG旋回特征的变化反映在记录中，由植被的重新组织，从密度到偏心率-节奏的周期。基于树木类群丰富度的定量分析，树木多样性的第一次大规模下降发生在0.94 Ma左右。随后的树木丰富度的变化在很大程度上是由G-IG周期的振幅和持续时间。树木丰富度下降发生在丰富的干草本协会，干旱影响树木种群生存的时期。对全球气候和区域植被变化之间的长期遗留影响的评估揭示了凉爽的间冰期条件对随后的冰川植被组成和多样性的重大影响。这种效应与高纬度地区的观测结果相反，在高纬度地区，已知冰川强度控制了随后的间冰期植被，证据表明，奥赫里德湖集水区是喜温和温带树种的避难所。
The sediment record from Lake Ohrid (Southwestern Balkans) represents the longest continuous lake archive in Europe, extending back to 1.36 Ma. We reconstruct the vegetation history based on pollen analysis of the DEEP core to reveal changes in vegetation cover and forest diversity during glacial-interglacial (G-IG) cycles and early basin development. The earliest lake phase saw a significantly different composition rich in relict tree taxa and few herbs. Subsequent establishment of a permanent steppic herb association around 1.2 Ma implies a threshold response to changes in moisture availability and temperature and gradual adjustment of the basin morphology. A change in the character of G-IG cycles during the Early-Middle Pleistocene Transition is reflected in the record by reorganization of the vegetation from obliquity-to eccentricity-paced cycles. Based on a quantitative analysis of tree taxa richness, the first large-scale decline in tree diversity occurred around 0.94 Ma. Subsequent variations in tree richness were largely driven by the amplitude and duration of G-IG cycles. Significant tree richness declines occurred in periods with abundant dry herb associations, pointing to aridity affecting tree population survival. Assessment of long-term legacy effects between global climate and regional vegetation change reveals a significant influence of cool interglacial conditions on subsequent glacial vegetation composition and diversity. This effect is contrary to observations at high latitudes, where glacial intensity is known to control subsequent interglacial vegetation, and the evidence demonstrates that the Lake Ohrid catchment functioned as a refugium for both thermophilous and temperate tree species.