scholarly journals A new terrestrial palaeoenvironmental record from the Bering Land Bridge and context for human dispersal

2018 ◽  
Vol 5 (6) ◽  
pp. 180145 ◽  
Author(s):  
Matthew J. Wooller ◽  
Émilie Saulnier-Talbot ◽  
Ben A. Potter ◽  
Soumaya Belmecheri ◽  
Nancy Bigelow ◽  
...  
Keyword(s):  
Climate Models ◽  
Environmental Changes ◽  
Land Bridge ◽  
Human Dispersal ◽  
South Central ◽  
Bering Land Bridge ◽  
Last Glaciation ◽  
Close Proximity ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Palaeoenvironmental records from the now-submerged Bering Land Bridge (BLB) covering the Last Glacial Maximum (LGM) to the present are needed to document changing environments and connections with the dispersal of humans into North America. Moreover, terrestrially based records of environmental changes are needed in close proximity to the re-establishment of circulation between Pacific and Atlantic Oceans following the end of the last glaciation to test palaeo-climate models for the high latitudes. We present the first terrestrial temperature and hydrologic reconstructions from the LGM to the present from the BLB's south-central margin. We find that the timing of the earliest unequivocal human dispersals into Alaska, based on archaeological evidence, corresponds with a shift to warmer/wetter conditions on the BLB between 14 700 and 13 500 years ago associated with the early Bølling/Allerød interstadial (BA). These environmental changes could have provided the impetus for eastward human dispersal at that time, from Western or central Beringia after a protracted human population standstill. Our data indicate substantial climate-induced environmental changes on the BLB since the LGM, which would potentially have had significant influences on megafaunal and human biogeography in the region.

scholarly journals Past, present and future biomes in Beringia: Comparison between simulations and pollen analysis

2018 ◽  
Author(s):  
Kazuyuki Saito ◽  
Amy Hendricks ◽  
John Walsh ◽  
Nancy Bigelow
Keyword(s):  
Cmip5 Models ◽  
Climate Data ◽  
Vegetation Model ◽  
Land Bridge ◽  
Study Region ◽  
Bering Land Bridge ◽  
Near Future ◽  
Warm Temperate ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Abstract. Past, present and future biomes in Beringia, a region including Alaska and Eastern Russia, were simulated using an equilibrium vegetation model, BIOME4 and a statistical downscaling method in order to illustrate their geographical and temporal changes. Outputs form five CMIP5 models were utilized to represent the climate for four time periods, i.e., the Last Glacial Maximum (LGM; 21 ka), the mid-Holocene Optimum (6 ka), the modern period, and the near future (the end of this century under a RCP8.5 scenario). Present-day biome simulations were generally consistent with current vegetation observations in the study region. Pollen samples indicate that the Bering Land Bridge was covered almost entirely by cushionforb and graminoid tundra during the LGM, whereas the paleoclimate simulations show large across-model variations in this region. Three out of the five modelsʼ climate data produce evergreen and deciduous taiga at 21 ka in what is now southwestern Alaska and southeastern Bering continental shelf. The 6 ka simulations are in better agreement with pollen-based distributions of biomes. Future simulations show a general northward shift of biomes, including intrusions of cool and warm-temperate mixed, and cool coniferous forests above 60° N, especially in southwest Alaska.

scholarly journals An Orchid in Retrograde: Climate-Driven Range Shift Patterns of Ophrys helenae in Greece

Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 470
Author(s):  
Martha Charitonidou ◽  
Konstantinos Kougioumoutzis ◽  
John M. Halley
Keyword(s):  
Climate Change ◽  
Climate Models ◽  
Species Distribution Modelling ◽  
Range Shift ◽  
Last Interglacial ◽  
Distribution Modelling ◽  
Species Response ◽  
Northwestern Greece ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Climate change is regarded as one of the most important threats to plants. Already species around the globe are showing considerable latitudinal and altitudinal shifts. Helen’s bee orchid (Ophrys helenae), a Balkan endemic with a distribution center in northwestern Greece, is reported to be expanding east and southwards. Since this southeastern movement goes against the usual expectations, we investigated via Species Distribution Modelling, whether this pattern is consistent with projections based on the species’ response to climate change. We predicted the species’ future distribution based on three different climate models in two climate scenarios. We also explored the species’ potential distribution during the Last Interglacial and the Last Glacial Maximum. O. helenae is projected to shift mainly southeast and experience considerable area changes. The species is expected to become extinct in the core of its current distribution, but to establish a strong presence in the mid- and high-altitude areas of the Central Peloponnese, a region that could have provided shelter in previous climatic extremes.

Arctic archaeologies: recent work on Beringia

Antiquity ◽  
2015 ◽  
Vol 89 (345) ◽  
pp. 740-742 ◽  
Author(s):  
Herbert Maschner
Keyword(s):  
Bering Sea ◽  
North Pacific ◽  
Yukon Territory ◽  
The Arctic ◽  
Land Bridge ◽  
Far North ◽  
North East ◽  
Bering Land Bridge ◽  
Last Glaciation ◽  
The Bering Sea

This review considers three books on the archaeology of territories situated around the Bering Sea—a region often referred to as Beringia, adopting the term created for the Late Pleistocene landscape that extended from north-east Asia, across the Bering Land Bridge, to approximately the Yukon Territory of Canada. This region is critical to the archaeology of the Arctic for two fundamental reasons. First, it is the gateway to the Americas, and was certainly the route by which the territory was colonised at the end of the last glaciation. Second, it is the place where the entire Aleut-Eskimo (Unangan, Yupik, Alutiiq, Inupiat and Inuit) phenomenon began, and every coastal culture from the far north Pacific, to Chukotka, to north Alaska, and to arctic Canada and Greenland, has its foundation in the cultural developments that occurred around the Bering Sea.

scholarly journals Mitochondrial Genome Diversity in the Central Siberian Plateau with Particular Reference to Prehistory of Northernmost Eurasia

2019 ◽  
Author(s):  
S. V. Dryomov ◽  
A. M. Nazhmidenova ◽  
E. B. Starikovskaya ◽  
S. A. Shalaurova ◽  
N. Rohland ◽  
...  
Keyword(s):  
Geographic Area ◽  
Mtdna Sequences ◽  
The Past ◽  
South Central ◽  
Sayan Region ◽  
History Of ◽  
Mitochondrial Genome Diversity ◽  
The Last Glacial Maximum ◽  
Complete Mtdna ◽  
The Last Glacial

AbstractThe Central Siberian Plateau was last geographic area in Eurasia to become habitable by modern humans after the Last Glacial Maximum (LGM). Through comprehensive mitochondrial DNA genomes retained in indigenous Siberian populations, the Ket, Tofalar, and Todzhi - we explored genetic links between the Yenisei-Sayan region and Northeast Eurasia over the last 10,000 years. Accordingly, we generated 218 new complete mtDNA sequences and placed them into compound phylogenies along with 7 newly obtained and 70 published ancient mt genomes. Our findings reflect the origins and expansion history of mtDNA lineages that evolved in South-Central Siberia, as well as multiple phases of connections between this region and distant parts of Eurasia. Our result illustrates the importance of jointly sampling modern and prehistoric specimens to fully measure the past genetic diversity and to reconstruct the process of peopling of the high latitudes of the Siberian subcontinent.

Thermodynamic Scaling of the Hydrological Cycle of the Last Glacial Maximum

2012 ◽  
Vol 25 (3) ◽  
pp. 992-1006 ◽  
Author(s):  
William R. Boos
Keyword(s):  
Water Vapor ◽  
Last Glacial Maximum ◽  
Climate Models ◽  
Hydrological Cycle ◽  
High Latitudes ◽  
Last Glacial ◽  
The Tropics ◽  
The Last Glacial Maximum ◽  
Circulation Changes ◽  
The Last Glacial

Abstract In climate models subject to greenhouse gas–induced warming, vertically integrated water vapor increases at nearly the same rate as its saturation value. Previous studies showed that this increase dominates circulation changes in climate models, so that precipitation minus evaporation (P − E) decreases in the subtropics and increases in the tropics and high latitudes at a rate consistent with a Clausius–Clapeyron scaling. This study examines whether the same thermodynamic scaling describes differences in the hydrological cycle between modern times and the last glacial maximum (LGM), as simulated by a suite of coupled ocean–atmosphere models. In these models, changes in water vapor between modern and LGM climates do scale with temperature according to Clausius–Clapeyron, but this thermodynamic scaling provides a poorer description of the changes in P − E. While the scaling is qualitatively consistent with simulations in the zonal mean, predicting higher P − E in the subtropics and lower P − E in the tropics and high latitudes, it fails to account for high-amplitude zonal asymmetries. Large horizontal gradients of temperature change, which are often neglected when applying the scaling to next-century warming, are shown to be important in large parts of the extratropics. However, even with this correction the thermodynamic scaling provides a poor quantitative fit to the simulations. This suggests that circulation changes play a dominant role in regional hydrological change between modern and LGM climates. Changes in transient eddy moisture transports are shown to be particularly important, even in the deep tropics. Implications for the selection and interpretation of climate proxies are discussed.

Problems in the Stone Age of South-East Asia

1993 ◽  
Vol 59 ◽  
pp. 1-15 ◽  
Author(s):  
T. E. G. Reynolds
Keyword(s):  
East Asia ◽  
Late Pleistocene ◽  
Environmental Changes ◽  
Middle Pleistocene ◽  
South East Asia ◽  
Site Location ◽  
Land Area ◽  
Dominant Characteristic ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Whilst research has shown many faults with the Movius scheme of a Middle Pleistocene group of Chopper/Chopping tool industries in South-East Asia, it remains a fact that pebble tool industries are still the dominant characteristic of the South-East Asian record. Exploration has now revealed hundreds of Late Pleistocene and Holocene sites in Mainland South-East Asia and these are archaeologically very different from cave sites in Europe. Further problems exist with the current nomenclature of later industries, such as the Hoabinhian and the Neolithic, for there is a large amount of overlap between such assemblages. Should such factors as economy, site location, etc. be used to assist clarification of such problems?This paper outlines some of these issues and reveals that the pebble tool tradition as it is widely known in South-East Asia is a relatively recent phenomenon dating back to the Last Glacial Maximum (LGM). A possible reason for the change from flake to pebble tool industrial types and in the visibility of sites is the environmental changes and rise in sea level which submerged over half the available land area in the region during the Late Pleistocene. An existing broad spectrum system of exploitation was likely to have been intensified as a result of this.

scholarly journals A new global reconstruction of temperature changes at the Last Glacial Maximum

2013 ◽  
Vol 9 (1) ◽  
pp. 367-376 ◽  
Author(s):  
J. D. Annan ◽  
J. C. Hargreaves
Keyword(s):  
Last Glacial Maximum ◽  
Climate Models ◽  
State Of The Art ◽  
Glacial Maximum ◽  
Proxy Data ◽  
Temperature Changes ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
Global Mean ◽  
The Last Glacial

Abstract. Some recent compilations of proxy data both on land and ocean (MARGO Project Members, 2009; Bartlein et al., 2011; Shakun et al., 2012), have provided a new opportunity for an improved assessment of the overall climatic state of the Last Glacial Maximum. In this paper, we combine these proxy data with the ensemble of structurally diverse state of the art climate models which participated in the PMIP2 project (Braconnot et al., 2007) to generate a spatially complete reconstruction of surface air (and sea surface) temperatures. We test a variety of approaches, and show that multiple linear regression performs well for this application. Our reconstruction is significantly different to and more accurate than previous approaches and we obtain an estimated global mean cooling of 4.0 ± 0.8 °C (95% CI).

scholarly journals Phylogeography of post-Pleistocene population expansion in Dasyscyphella longistipitata (Leotiomycetes, Helotiales), an endemic fungal symbiont of Fagus crenata in Japan

MycoKeys ◽  
2020 ◽  
Vol 65 ◽  
pp. 1-24
Author(s):  
Jaime Gasca-Pineda ◽  
Patricia Velez ◽  
Tsuyoshi Hosoya
Keyword(s):  
Genetic Diversity ◽  
Environmental Changes ◽  
Continuous Distribution ◽  
Population Expansion ◽  
Fagus Crenata ◽  
High Genetic Diversity ◽  
Environmental Suitability ◽  
The Japanese Archipelago ◽  
The Last Glacial Maximum ◽  
The Last Glacial

During the Last Glacial Maximum (LGM), drastic environmental changes modified the topology of the Japanese Archipelago, impacting species distributions. An example is Fagus crenata, which has a present continuous distribution throughout Japan. However, by the end of the LGM it was restricted to southern refugia. Similarly, Dasyscyphella longistipitata (Leotiomycetes, Helotiales, Lachnaceae) occurs strictly on cupules of F. crenata, sharing currently an identical distribution. As the effects of the LGM remain poorly understood for saprobiotic microfungal species, herein we identified past structuring forces that shaped the current genetic diversity within D. longistipitata in relation to its host using a phylogeographic approach. We inferred present and past potential distributions through species distribution modeling, identifying environmental suitability areas in mid-southern Japan from which subsequent colonizations occurred. Our findings suggest that current high genetic diversity and lack of genetic structure within D. longistipitata are the result of recent multiple re-colonization events after the LGM.

scholarly journals Caracterização paleohidrológica de estruturas sedimentares quaternárias através de análises macroscópias e microscópicas: do registro sedimentar local aos indícios de mudanças globais

2001 ◽  
Vol 28 (2) ◽  
pp. 183 ◽  
Author(s):  
MARCELO ACCIOLY TEIXEIRA DE OLIVEIRA ◽  
GISELE CAMARGO ◽  
JULIO CÉSAR PAISANI ◽  
MAURÍCIO CAMARGO FILHO
Keyword(s):  
Environmental Changes ◽  
Microscopic Analysis ◽  
Ice Cores ◽  
Evolutionary Pattern ◽  
Global Environmental ◽  
The Tropics ◽  
Global Environmental Changes ◽  
Geomorphic Surfaces ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Preliminary results based on macroscopic and microscopic analysis of quaternary sedimentary structures and paleosoils preserved on footslope deposits are presented in this paper. Together with geochronologic estimates for the main pedo-stratigraphic units, the paper suggests an evolutionary pattern for geomorphic surfaces situated at the highlands of the States of Paraná and Santa Catarina, Southern Brazil. the association of that pattern with global environmental changes is postulated. Based on sedimentologic and geomorphologic evidences, paleohydrologic interpretations suggest the predominance of relative wet local climates at the end of the Pleistocene. Indeed, 14C ages of paleosoils in the study area suggest the development of organic and hydromorphic soils during the coldest periods of isotopic stages 3 and 2. As peat horizons need anaerobic conditions to fully develop, such a result lead us to challenge the predominant role attributed to lower precipitation as a cause of geomorphic and vegetation changes during the Quaternary in the tropics and subtropics. Indeed, together with lower precipitation. Lower temperatures and, most important, an excess of precipitation over evaporation should be considered as the same importance. In so far, the indication of waterlogged soils, even during the Last Glacial Maximum, well explain the pattern of evolution of geomorphic surfaces and related pedo-stratigraphic features in the area. Indeed, taking into account the calibrated isotopic curves from Antarctic ice cores for the last 40 ka, we conclude that soil development and colluvial building by diffuse processes prevailed during Stadials, while pulses of erosive incision punctuated Insterstadials.

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