After Last Glacial Maximum: The third migration

A critical analysis of “Real World” data concerning the genetic origins of people, archaeology and palaeoclimatic conditions, demonstrates possibilities of population migration for third time in ancient history, from East to West after Last Glacial Maximum (LGM), which gave the foundations of modern human civilization.     

末次盛冰期以来云南异龙湖的环境演变——来自地球化学沉积记录的证据

通过对云南异龙湖4.56 m沉积岩芯进行X射线荧光光谱分析(XRF),结合13个AMS14C测年结果,获得了高分辨率元素地球化学序列。异龙湖岩芯中元素的因子分析显示,F1因子揭示了沉积地球化学元素的来源,其正载荷代表了流域外源物质输入加强,而负载荷则指示了湖泊自生碳酸盐沉淀的增加,F2因子指示了湖泊氧化还原状态,F3因子可能与人类活动有关。在此基础上结合磁化率、矿物组成及有机质含量等指标,对异龙湖沉积环境演化过程进行探讨。结果表明,在末次盛冰期期间(26000—17000 cal. yr. BP),区域气候特征是气温低、降水少;在17000—14500 cal. yr. BP期间,异龙湖经历了显著的干旱气候,可能与亚洲夏季风突然减弱有关; 14500—9000 cal. yr. BP,异龙湖经历了显著的高湖面阶段,与滇池高水位时期基本一致,表明流域降水丰沛,外源物质输入增加; 9000—6000 cal. yr. BP期间,区域温度增加导致流域干旱化加剧,此阶段与西南地区全新世大暖期(全新世适宜期)相对应; 6000 cal. yr. BP以后外援物质输入锐减可能指示了区域降水的降低。异龙湖地球化学沉积记录揭示的环境演变过程与区域气候环境变化具有一致性,也具有明显的特殊性。     

Late Pleistocene and Holocene development of the felid fauna (Felidae) of Europe: a review

In the fossil deposits of the Late Pleistocene ( c . 115 000–11 500 years ago), five felid species are recorded in Europe: the wildcat Felis silvestris , Eurasian lynx Lynx lynx , Iberian lynx Lynx pardinus , leopard Panthera pardus and cave lion Panthera leo spelaea . In the Holocene, Europe was colonized by F. silvestris , L. lynx and L. pardinus as well as the lion Panthera leo . The status of P. pardus in post-glacial Europe is unknown. So far, only sparse records indicate that P. pardus survived into the early Holocene. During the Late Glacial, both L. lynx and L. pardinus occurred on the Iberian Peninsula. However, from the Holocene, only the Iberian lynx is recorded in this region. There are subfossil records that indicate that L. pardinus also occurred in central and western France until c . 3000 years ago. Surprisingly, with reservations on the determination of the bones (by J. Altuna), both lions and cave lions seem to be recorded in the Iberian Peninsula in the Late Glacial. There are published records of the lion P. leo in the northern Iberian Peninsula from the early Holocene. However, its presence in Europe on the basis of subfossil records was proven initially from the Atlantic period. In Ponto-Mediterranean regions of Europe, the lion is recorded from the Atlantic to the younger sub-Atlantic.     

Phylogeographic analyses suggest that a deciduous species (Ostryopsis davidiana Decne., Betulaceae) survived in northern China during the Last Glacial Maximum

Aim Palaeontologial data suggest that all temperate forest species in northern China migrated southwards during the Last Glacial Maximum (LGM) and recolonized post‐glacially within the Holocene. We tested this assumption using phylogeographical studies of a temperate deciduous shrub species (Ostryopsis davidiana Decne., Betulaceae), which has a wide distribution in northern China. Location Northern China. Methods We sequenced two chloroplast DNA (cpDNA) fragments (trnL–trnF and psbA–trnH, together about 1300 bp in length) of 294 plants from 21 populations across the total distribution range of this species. We used maximum parsimony and haplotype network methods to construct phylogenetic relationships among haplotypes. Results The analysis of cpDNA variation identified eight haplotypes. A single haplotype was fixed in all populations except for one population that was polymorphic, having two haplotypes. The population subdivisions were extremely high (G_ST = 0.972 and N_ST = 0.974), suggesting very low gene flow between populations. Haplotypes clustered into two tentative clades, both of which occur in the southern region of the species’ range but only one of which occurs in the northern region. Across the sampled populations, the haplotype distributions were differentiated geographically. Main conclusions Our analyses suggest that multiple refugia were maintained across the range of O. davidiana in both northern (north of the Qing Mountains) and southern (south of the Qing Mountains) regions during the LGM rather than that the species survived only in the south and subsequently colonized northwards. The extremely low within‐population diversity of this species suggests strong bottleneck or founder effects within each fragmented region during the Quaternary climatic oscillations. These findings provide important clues for understanding range shifts and changes in within‐ and/or between‐population genetic diversity of temperate forests in response to past climatic oscillations in northern China.     

Last Glacial Maximum ages for robust humans at Kow Swamp, southern Australia

The Kow Swamp people are a fossil population of robust modern humans. We report optically stimulated luminescence (OSL) ages on sediments from Kow Swamp that are at odds with radiocarbon ages obtained previously for the site. The calibrated 14C ages place the Kow Swamp people in the period 15-9 ka. Our single aliquot OSL ages suggest that they lived around the time of the Last Glacial Maximum (LGM) between 22 and 19 ka. An LGM age for the Kow Swamp people is supported by palaeoenvironmental reconstruction. The shoreline silt, in which most of them were interred, was deposited by high lake levels between 26 and 19 ka. Few robust people were left after 19 ka when a sand lunette formed. Climate change may explain the demise of this unusual genetic population.     

A Matrilineal Genetic Legacy from the Last Glacial Maximum Confers Susceptibility to Schizophrenia in Han Chinese

Mitochondrial dysfunction has been widely reported in schizophrenia patients. To dissect the matrilineal structure of Han Chinese with or without schizophrenia and to decipher the maternal influence and evolutionary history of schizophrenia, a total of 1212 schizophrenia patients and 1005 matched healthy controls, all of Han Chinese origin, were recruited in Hunan Province, China. We classified haplogroup for each individual based on mitochondrial DNA （mtDNA） sequence variations and compared the haplogroup distribution pattern between cases and controls. Haplogroup B5a presented a higher frequency in cases than in controls （P = 0.02, OR = 1.67, 95% CI = [1.09, 2.56]）, and this result could be confirmed by permutation analysis. Age estimation of haplogroup B5a in cases revealed a much younger age than that of controls, which was coincident with the Northern Hemisphere deglaciation at the end of the Last Glacial Maximum. Analysis of complete mtDNA in five patients belonging to haplogroup B5a showed that this background effect might be caused by haplogroup- defining variants m.8584G〉A and m.10398A〉G. Our results showed that matrilineal risk factor for schizophrenia had an ancient origin and might acquire a predisposing effect on schizophrenia due to the environment change and/or orchestration with other nuclear genetic factors appeared recently in human evolutionary history.     

小叶栎分布格局对末次盛冰期以来气候变化的响应

小叶栎(Quercus chenii)是华东植物区系的代表树种, 具有很高的生态、经济价值。为重建冰期以来小叶栎地理分布格局的变迁历史、了解环境因子对潜在地理分布的制约机制, 为小叶栎种质资源保护和管理提供科学依据, 该研究基于55条分布记录和8个环境变量, 利用MaxEnt模型模拟小叶栎在末次盛冰期、全新世中期、现代和2070年(温室气体排放情景为典型浓度目标8.5)的潜在分布区, 利用多元环境相似度面和最不相似变量分析探讨气候变迁过程中环境异常区域和引起潜在地理分布改变的关键因素, 综合应用贡献率及置换重要值比较、Jackknife检验评估制约现代地理分布的主要因子, 采用响应曲线确定环境变量的适宜区间。研究结果表明: MaxEnt模型的预测准确度极高, 受试者工作特征曲线下的面积(AUC值)达0.9869 ± 0.0045; 现代高度适宜区在安徽南部、浙江西部、江西东北部和湖北东部; 影响小叶栎地理分布的主要气候因子为气温和降水量, 气温更重要; 最干季平均气温可能是制约小叶栎向北分布的关键因素; 末次盛冰期时, 小叶栎高度适宜区位于东海大陆架内; 全新世中期适宜分布区轮廓已与现代近似; 2070年适宜分布区向北移, 高度适宜区面积增大, 与末次盛冰期、全新世中期和现代相比, 这一时期的气候异常程度最高。气温季节变化和降水季节变化可能是引起地理分布变迁的重要气候因素。     

Mitogenetic structure of brown bears (Ursus arctos L.) in northeastern Europe and a new time frame for the formation of European brown bear lineages

We estimated the phylogenetic relationships of brown bear maternal haplotypes from countries of northeastern Europe (Estonia, Finland and European Russia), using sequences of mitochondrial DNA (mtDNA) control region of 231 bears. Twenty-five mtDNA haplotypes were identified. The brown bear population in northeastern Europe can be divided into three haplogroups: one with bears from all three countries, one with bears from Finland and Russia, and the third composed almost exclusively of bears from European Russia. Four haplotypes from Finland and European Russia matched exactly with haplotypes from Slovakia, suggesting the significance of the current territory of Slovakia in ancient demographic processes of brown bears. Based on the results of this study and those from the recent literature, we hypothesize that the West Carpathian Mountains have served either as one of the northernmost refuge areas or as an important movement corridor for brown bears of the Eastern lineage towards northern Europe during or after the last ice age. Bayesian analyses were performed to investigate the temporal framework of brown bear lineages in Europe. The molecular clock was calibrated using Beringian brown bear sequences derived from radiocarbon-dated ancient samples, and the estimated mutation rate was 29.8% (13.3%-47.6%) per million years. The whole European population and Western and Eastern lineages formed about 175,000, 70,000 and 25,000 years before present, respectively. Our approach to estimating the time frame of brown bear evolution demonstrates the importance of using an appropriate mutation rate, and this has implications for other studies of Pleistocene populations.     

末次盛冰期以来观光木的潜在地理分布变迁

观光木(Tsoongiodendron odorum)是木兰科的古老残遗物种, 目前正面临严峻的生存威胁, 属于极小种群濒危植物。通过生态位模型(ENM)能够重建观光木地理分布格局的历史变迁, 探究气候变化对该物种分布的影响, 并了解其地理分布与气候需求间的关系, 从而为全球变暖背景下观光木的保护提供理论基础。该文基于96条现代分布记录和8个环境变量, 采用最大熵(MaxEnt)模型模拟观光木在末次盛冰期、全新世中期、现代和未来(2061-2080年, RCP 8.5)的潜在分布区, 利用SDM toolbox分析观光木的地理空间变化, 并综合贡献率、置换重要值和Jackknife检验来评估气候因子的重要性。研究结果表明: (1)观光木的高度适生区在南岭地区, 末次盛冰期时没有大尺度向南退缩, 很可能在山区避难所原地存活; (2)在全新世中期和未来两个增温的气候情境下, 观光木的分布区均表现为缩减, 其中未来分布的减幅更大, 表明气候变暖对观光木的生长有一定的负面影响; (3)总体上看, 观光木各个时期的地理分布范围相对稳定, 说明观光木对气候变化有一定的适应能力, 人为活动或自身繁育问题可能是致濒的重要原因, 并建议对广东和广西群体进行优先保护。     

Prokaryotes in the WAIS Divide ice core reflect source and transport changes between Last Glacial Maximum and the early Holocene

We present the first long‐term, highly resolved prokaryotic cell concentration record obtained from a polar ice core. This record, obtained from the West Antarctic Ice Sheet (WAIS) Divide (WD) ice core, spanned from the Last Glacial Maximum (LGM) to the early Holocene (EH) and showed distinct fluctuations in prokaryotic cell concentration coincident with major climatic states. The time series also revealed a ~1,500‐year periodicity with greater amplitude during the Last Deglaciation (LDG). Higher prokaryotic cell concentration and lower variability occurred during the LGM and EH than during the LDG. A sevenfold decrease in prokaryotic cell concentration coincided with the LGM/LDG transition and the global 19 ka meltwater pulse. Statistical models revealed significant relationships between the prokaryotic cell record and tracers of both marine (sea‐salt sodium [ssNa]) and burning emissions (black carbon [BC]). Collectively, these models, together with visual observations and methanosulfidic acid (MSA) measurements, indicated that the temporal variability in concentration of airborne prokaryotic cells reflected changes in marine/sea‐ice regional environments of the WAIS. Our data revealed that variations in source and transport were the most likely processes producing the significant temporal variations in WD prokaryotic cell concentrations. This record provided strong evidence that airborne prokaryotic cell deposition differed during the LGM, LDG, and EH, and that these changes in cell densities could be explained by different environmental conditions during each of these climatic periods. Our observations provide the first ice‐core time series evidence for a prokaryotic response to long‐term climatic and environmental processes.     

Responses of the distribution pattern of Quercus chenii to climate change following the Last Glacial Maximum

Aims Quercus chenii is a representative species of the flora in East China, with high ecological and economic values. Here, we aim to simulate the changes in the distribution pattern of this tree species following the Last Glacial Maximum (LGM) and to explore how climatic factors constrain the potential distribution, so as to provide scientific basis for protection and management of the germplasm resources in Q. chenii.
Methods Based on 55 presence point records and data on eight environmental variables, we simulated the potential distribution of Q. chenii during the Last Glacial Maximum, mid-Holocene, present and the year 2070 (the scenario of greenhouse gas emission is Representative Concentration Pathway 8.5) with MaxEnt model. The novel climate area and main factors influencing the changes in distribution pattern were evaluated by multivariate environmental similarity surface analysis and the most dissimilar variable analysis. The importance of environmental variables was evaluated by percent contribution, permutation importance and Jackknife test. Response curves were used to estimate the suitable value range of each variable.
Important findings The accuracy of MaxEnt model is very high, as indicated by the value of the area under the receiver operator characteristic curve of 0.9869 ± 0.0045. The highly suitable region for the present distribution covers southern Anhui, western Zhejiang, northeastern Jiangxi and eastern Hubei. The main factors affecting the potential distribution of Q. chenii are temperature and precipitation, with the former being more important. Mean temperature of the driest quarter is likely the main factor restricting Q. chenii growing in the north. During the LGM, the East China Sea Shelf occurs as the highly suitable region for the distribution of Q. chenii. In the mid-Holocene, the outline of the suitable area for the distribution of Q. chenii is similar to the present. The potential distribution region will likely move northward and experience an area expansion under the climate condition in 2070. At that time, climate anomaly will also be most severe compared to the LGM, mid-Holocene and present. Temperature seasonality and precipitation seasonality may be the main climatic factors promoting changes in the distribution pattern of Q. chenii.     

末次冰盛期以来香果树潜在地理分布格局变迁

香果树是中国特有的单种属孑遗树种,探讨末次冰盛期以来香果树在中国的潜在地理分布格局及其变化,对研究茜草科乃至中国亚热带植物区系的系统发育、古生态和古气候变迁等具有重要作用。研究基于最大熵MaxEnt模型与ArcGIS空间分析技术,利用香果树分布点位信息与气候数据,构建其在末次冰盛期(LGM)、全新世中期(MID)、当前(1960—1990年)以及未来(2061—2080年)的潜在地理分布格局,探明其分布格局的变化趋势,揭示引起其潜在地理分布格局改变的关键因子。结果表明,香果树当前适生区总面积约197.575×10⁴ km²,主要位于中国亚热带地区,其中高适生区集中分布于四川盆周山地、武陵山与武夷山地区,最干季度平均温、最湿月降水量、最冷季度降水量是限制其分布的主要气候因子。末次冰盛期时香果树广泛分布于中国亚热带地区,随后适生区开始缩减且向内陆退缩,全新世中期后适生区面积继续缩减并向高纬度地区迁移。随着全球气候变暖,在不同排放情景下香果树适宜生境面积均进一步缩减并向西与高纬度地区迁移。总体而言,从末次冰盛期至未来,香果树适生区呈现持续缩减并向西...     

The role of glacial cycles in promoting genetic diversity in the Neotropics: the case of cloud forests during the Last Glacial Maximum

The increasing aridity during the Last Glacial Maximum (LGM) has been proposed as a major factor affecting Neotropical species. The character and intensity of this change, however, remains the subject of ongoing debate. This review proposes an approach to test contrasting paleoecological hypotheses by way of their expected demographic and genetic effects on Neotropical cloud forest species. We reviewed 48 paleoecological records encompassing the LGM in the Neotropics. The records show contrasting evidence regarding the changes in precipitation during this period. Some regions remained fairly moist and others had a significantly reduced precipitation. Many paleoecological records within the same region show apparently conflicting evidence on precipitation and forest stability. From these data, we propose and outline two demographic/genetic scenarios for cloud forests species based on opposite precipitation regimes: the dry refugia and the moist forests hypotheses. We searched for studies dealing with the population genetic structure of cloud forest and other montane taxa and compared their results with the proposed models. To date, the few available molecular studies show insufficient genetic evidence on the predominance of glacial aridity in the Neotropics. In order to disentangle the climatic history of the Neotropics, the present study calls for a general multi‐disciplinary approach to conduct future phylogeographic studies. Given the contradictory paleoecological information, population genetic data on Neotropical cloud forest species should be used to explicitly test the genetic consequences of competing paleoecological models.     

Fossil evidence and phylogeography of temperate species: 'glacial refugia' and post-glacial recolonization

We present a short synthesis of the Pleistocene distribution dynamics and phylogeographic recolonization hypotheses for two temperate European mammal species, the red deer ( Cervus elaphus ) and the roe deer ( Capreolus capreolus ), for which high-resolution patterns of fossil evidence and genetic data sets are available. Such data are critical to an understanding of the role of hypothesized glacial refugia. Both species show a similar pattern: a relatively wide distribution in the southern part of Central Europe 60,000–25,000 years ago, and a strong restriction to areas in southern Europe for nearly 10,000 years during the Last Glacial Maximum (LGM) and the early Late Glacial (25,000–14,700 years ago). With the beginning of Greenland Interstadial 1 (Bølling/Allerød warming, c. 14,700–11,600 years ago) a sudden range expansion into Central Europe is visible, but the colonization of most of Central Europe, including the northern European Lowlands, only began in the early Holocene. In a European context, regions where the species were distributed during the LGM and early Late Glacial are most relevant as potential origins of recolonization processes, because during these c. 10,000 years distribution ranges were smaller than at any other time in the Late Quaternary. As far as the present distribution of temperate species and their genetic lineages is concerned, so-called 'cryptic refugia' are important only if the species are actually confirmed there during the LGM, as otherwise they could not possibly have contributed to the recolonization that eventually resulted in the present distribution ranges.     

多星韭分布格局对末次盛冰期以来气候的响应

该研究以分布区主要在横断山脉的多星韭为对象,基于最大熵模型(MaxEnt)和地理信息系统(ArcGIS)模拟了多星韭在末次盛冰期、全新世中期、当前以及未来的分布格局,以探讨多星韭对末次盛冰期以来气候变化的响应。结果显示:(1)多星韭当前的分布区主要受到最暖季度降水量、年均温变化范围和温度季节性变化标准差3个气候因子的影响;海拔对多星韭的当前分布也有着较大的影响。(2)最大熵模型的模拟精度较高(AUC=0.98)。(3)根据多星韭各个时期分布面积的变化得出多星韭与部分高山植物相似,相比当前的分布,多星韭末次盛冰期的分布区发生了较为明显的扩张。研究推测,未来多星韭的分布区将向西移动。