Fossil rodents in Mylodon Cave as indicators of late Pleistocene–Holocene environmental evolution in southern Chile

2021 ◽  
pp. 1-17
Author(s):  
Ulyses F.J. Pardiñas ◽  
Luis Borrero ◽  
Fabiana M. Martin ◽  
Mauricio Massone ◽  
Fernando J. Fernández
Keyword(s):  
Late Pleistocene ◽  
Small Mammal ◽  
Late Holocene ◽  
Environmental Changes ◽  
First Record ◽  
Climatic Conditions ◽  
Southern Chile ◽  
Environmental Evolution ◽  
Local Conditions ◽  
Almost All

Abstract We conducted the first taphonomic and paleoenvironmental study based on late Pleistocene–Holocene small mammal remains recovered from the famous Mylodon Cave (Cerro Benítez area, Última Esperanza, Chile). Most of the analyzed material came from the extensive excavations made by Earl Saxon in 1976. We also studied late Holocene small mammal samples of the neighboring rock shelter Dos Herraduras 1. Analyzed remains were mostly produced by owls, probably living inside the caves. In Mylodon Cave, the higher values of girdle bones are consistent with a windblown litter. We recorded nine species of rodents, seven cricetids, and two caviomorphs; almost all the identified taxa integrate recent local communities. Late Pleistocene–Holocene assemblages are characterized by the chinchilla rat Euneomys, indicating unforested areas around the caves under cold and moist climatic conditions. Middle Holocene amelioration is reflected by incremental rodent species richness, including the first record of taxa clearly associated with forest (e.g., Abrothrix lanosa). Late Holocene assemblages are markedly stable, indicating local conditions similar to the current (historical) environment. Quaternary rodents from Cerro Benítez area do not indicate abrupt environmental changes during middle–late Holocene, but a progressive trend towards forest increase.

scholarly journals FAME (v1.0): a simple module to simulate the effect of planktonic foraminifer species-specific habitat on their oxygen isotopic content

2018 ◽  
Vol 11 (9) ◽  
pp. 3587-3603 ◽  
Author(s):  
Didier M. Roche ◽  
Claire Waelbroeck ◽  
Brett Metcalfe ◽  
Thibaut Caley
Keyword(s):  
Late Holocene ◽  
Simple Module ◽  
Climatic Conditions ◽  
Model Data ◽  
Planktonic Foraminifer ◽  
Planktonic Foraminifers ◽  
Oxygen Isotopic ◽  
Species Specific ◽  
Almost All ◽  
Multiproxy Approach

Abstract. The oxygen-18 to oxygen-16 ratio recorded in fossil planktonic foraminifer shells has been used for over 50 years in many geoscience applications. However, different planktonic foraminifer species generally yield distinct signals, as a consequence of their specific living habitats in the water column and along the year. This complexity is usually not taken into account in model–data integration studies. To overcome this shortcoming, we developed the Foraminifers As Modeled Entities (FAME) module. The module predicts the presence or absence of commonly used planktonic foraminifers and their oxygen-18 values. It is only forced by hydrographic data and uses a very limited number of parameters, almost all derived from culture experiments. FAME performance is evaluated using the Multiproxy Approach for the Reconstruction of the Glacial Ocean surface (MARGO) Late Holocene planktonic foraminifer calcite oxygen-18 and abundance datasets. The application of FAME to a simple cooling scenario demonstrates its utility to predict changes in planktonic foraminifer oxygen-18 to oxygen-16 ratio in response to changing climatic conditions.

scholarly journals Mid-to-late Holocene Temperature Evolution and Atmospheric Dynamics over Europe in Regional Model Simulations

2016 ◽  
Author(s):  
Emmanuele Russo ◽  
Ulrich Cubasch
Keyword(s):  
Late Holocene ◽  
Climate Models ◽  
Climate Model ◽  
Regional Climate ◽  
Climatic Conditions ◽  
Modes Of Variability ◽  
The North ◽  
Climate Reconstructions ◽  
The North Atlantic Oscillation ◽  
Almost All

Abstract. The improvement in resolution of climate models is always been mentioned as one of the most important factors when investigating past climatic conditions especially in order to evaluate and compare the results against proxy data. In this paper we present for the first time a set of high resolution simulations for different time slices of mid-to-late Holocene performed over Europe using a Regional Climate Model. Through a validation against a new pollen-based climate reconstructions dataset, covering almost all of Europe, we test the model performances for paleoclimatic applications and investigate the response of temperature to variations in the seasonal cycle of insolation, with the aim of clarifying earlier debated uncertainties, giving physically plausible interpretations of both the pollen data and the model results. The results reinforce previous findings showing that summertime temperatures were driven mainly by changes in insolation and that the model is too sensitive to such changes over Southern Europe, resulting in drier and warmer conditions. In winter, instead, the model does not reproduce correctly the same amplitude of changes, even if it captures the main pattern of the pollen dataset over most of the domain for the time periods under investigation. Through the analysis of variations in atmospheric circulation we suggest that, even though in some areas the discrepancies between the two datasets are most likely due to high pollen uncertanties, in general the model seems to underestimate the changes in the amplitude of the North Atlantic Oscillation, overestimating the contribution of secondary modes of variability

scholarly journals Phenological Plasticity and Adaptive Potential of Sugar Maple Populations

2021 ◽  
Author(s):  
guo xiali ◽  
Valentina Buttò ◽  
Yann Surget-Groba ◽  
Jian-Guo Huang ◽  
Sylvain Delagrange ◽  
...  
Keyword(s):  
Acer Saccharum ◽  
Sugar Maple ◽  
Environmental Changes ◽  
Terrestrial Ecosystems ◽  
Climatic Conditions ◽  
Global Changes ◽  
Bud Burst ◽  
Adaptive Potential ◽  
Local Conditions ◽  
Common Gardens

Abstract Global changes affect the growing conditions of terrestrial ecosystems, mismatching the phenological adaptation of plants to local climates at mid and high latitudes. Their long lifespan and slow reproductive cycles prevent trees from tracking the quick shift in their usual climatic conditions, thus endangering the survival of local populations. In this study, we explored the phenological plasticity and adaptive potential of bud burst in sugar maple (Acer saccharum Marsh.) seedlings from 30 Canadian origins with contrasting climates planted in two common gardens near and at the northern boundary of the species range. Bud development and leafing occurred in April-May, with complete bud burst lasting between 21 and 29 days. On average, bud swelling differed by 12 days between common gardens. However, this difference decreased to 4 days for complete leafing. Both factors site and seed origin affected bud burst, which represented the phenological plasticity and adaptation of sugar maple, respectively. Overall, the former (7.4–88.3%) contributed more than the latter (9.2–25.5%) to the variance in bud burst, despite the wide climatic range among the provenance origins compared with that at the two common gardens. Adaptation to local conditions provide the genetic tools for the survival of species across wide climatic ranges. Plasticity enables physiological responses of individuals to quick environmental changes. Our study demonstrated the major role of plasticity in bud phenology, and revealed the importance of investing resources in mechanisms dealing with the climatic challenges due to inter-annual variations in weather events.

Postglacial spread of hemlock (Tsuga) and vegetation history in Mount Revelstoke National Park, British Columbia, Canada

2003 ◽  
Vol 81 (2) ◽  
pp. 139-151 ◽  
Author(s):  
Sandra M Rosenberg ◽  
Ian R Walker ◽  
Rolf W Mathewes
Keyword(s):  
British Columbia ◽  
National Park ◽  
Late Holocene ◽  
Environmental Changes ◽  
Vegetation History ◽  
Climatic Conditions ◽  
Western Hemlock ◽  
Migration Route ◽  
Geological Evidence ◽  
Eagle Lake

To investigate postglacial environmental changes in southeastern British Columbia, subfossil pollen was analyzed from Eagle Lake, Mount Revelstoke National Park. Palynological evidence suggests that during the early Holocene, Eagle Lake was surrounded by an open forest. The pollen assemblage indicates that climatic conditions were warmer and drier than at present with high alder pollen values. Spruce and fir were common in local forests throughout the Holocene. Western hemlock pollen first occurs at approximately 3500 14C years BP. The migration path of western hemlock into this region is currently unclear. Data from palynological records appear insufficient to resolve the migration pattern, although several routes are possible. The available data support northward migration into southeastern British Columbia. The arrival of this conifer may be in response to the late Holocene increase in precipitation, as inferred from many lower elevation and coastal sites. Mountain hemlock pollen does not appear until about 2100 14C years BP. Mountain hemlock's migration route into southeastern British Columbia is also unresolved. In the late Holocene, the presence of mountain hemlock, and increases of Ericales and Valeriana sitchensis pollen, suggest a shift to the more open, cool, and moist conditions characteristic of the modern-day subalpine parkland. These climatic inferences correspond closely to those derived from other palynological and geological evidence throughout southern British Columbia.Key words: pollen, vegetation, Tsuga, hemlock, British Columbia, Holocene, climate.

Pollen Analysis of Hyena Coprolites and Sediments from Equus Cave, Taung, Southern Kalahari (South Africa)

1987 ◽  
Vol 28 (1) ◽  
pp. 144-156 ◽  
Author(s):  
Louis Scott
Keyword(s):  
South Africa ◽  
Late Pleistocene ◽  
Pollen Analysis ◽  
Late Holocene ◽  
Climatic Conditions ◽  
Optimal Temperature ◽  
Local Sources ◽  
Moisture Conditions

AbstractEquus Cave, in Quaternary tufa near Taung in the semiarid woodland of the southern Kalahari, yielded 2.5 m of sediment in which a rich assemblage of bones and coprolites was preserved. The fossils were accumulated mainly by hyenas during the late Pleistocene and Holocene. Pollen from coprolites reflects diet as well as vegetation over relatively large areas visited by hyenas, while pollen from sediments represents more local sources. The pollen sequence derived from coprolites and sediments demonstrates how the vegetation evolved from open grassland with small shrubs and occasional trees during the late Pleistocene, to open savanna with more small shurbs, then, during the last 7500 yr, to modern savanna. Temperatures were not more than 4°C cooler and it was slightly moister than today during the late Pleistocene phase; it became gradually warmer but relatively dry before optimal temperature and moisture conditions developed around 7500 yr B.P. Climatic conditions slightly less favorable for woodland occurred during part of the late Holocene.

scholarly journals Holocene tephrochronology around Cochrane (~47° S), southern Chile

2015 ◽  
Vol 43 (1) ◽  
pp. 1 ◽  
Author(s):  
Charles Stern ◽  
Patricio I. Moreno ◽  
William I. Henríquez ◽  
Rodrigo Villa-Martínez ◽  
Esteban Sagredo ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Late Holocene ◽  
Thin Layers ◽  
Southern Chile ◽  
The South ◽  
Hudson Volcano ◽  
Glass Color ◽  
Tephra Layers ◽  
Glass Chemistry ◽  
Lake Cores

Two Holocene tephras encountered in outcrops, cores and trenches in bogs, and lake cores in the area around Cochrane, southern Chile, are identified (based on their age, tephra glass color and morphology, mineralogy, and both bulk and glass chemistry) as H1 derived from Hudson volcano, and MEN1 derived from Mentolat volcano. New AMS radiocarbon ages indicate systematic differences between those determined in lake cores (MEN1=7,689 and H1=8,440 cal yrs BP) and surface deposits (MEN1=7,471 and H1=7,891 cal yrs BP), with the lake cores being somewhat older. H1 tephra layers range from 8 to 18 cm thick, suggesting that both the area of the 10 cm isopach and the volume of this eruption were larger than previously suggested, but not greatly, and that the direction of maximum dispersion was more to the south. MEN1 tephra layers range from 1-4 cm in thickness, indicating that this was probably a reasonably large (>5 km3) eruption. Some of the lake cores also contain thin layers (<2 cm) of late Holocene H2 tephra and the recent H3 (1991 AD) tephra, both derived from the Hudson volcano. No tephra evidence has been observed for any late Pleistocene tephra, nor for the existence of the supposed Arenales volcano, proposed to be located west of Cochrane.

scholarly journals FAME (v1.0): a simple module to simulate the effect of planktonic foraminifer species-specific habitat on their oxygen isotopic content

2017 ◽  
Author(s):  
Didier M. Roche ◽  
Claire Waelbroeck ◽  
Brett Metcalfe ◽  
Thibaut Caley
Keyword(s):  
Data Model ◽  
Late Holocene ◽  
Simple Module ◽  
Climatic Conditions ◽  
Data Sets ◽  
Planktonic Foraminifer ◽  
Planktonic Foraminifers ◽  
Oxygen Isotopic ◽  
Species Specific ◽  
Almost All

Abstract. The oxygen-18 signal recorded in fossil planktonic foraminifer shells has been used for over 50 years in many geoscience applications. However, different planktonic foraminifer species generally yield distinct oxygen-18 signals, as a consequence of their specific living habitats in the water column and along the year. This complexity is usually not taken into account in data – model integration studies. To overcome this shortcoming, we developed the FAME (Foraminifers As Modeled Entities) module. The module predicts the presence or absence of commonly used planktonic foraminifers, and their oxygen-18 values. It is only forced by hydrographic data and uses a very limited number of parameters, almost all derived from culture experiments. FAME performance is evaluated using MARGO Late Holocene planktonic foraminifer calcite oxygen-18 and abundances data sets. The application of FAME to a simple cooling scenario demonstrates its utility to predict changes in planktonic foraminifer oxygen-18 in response to changing climatic conditions.

scholarly journals Western equatorial African forest-savanna mosaics: a legacy of late Holocene climatic change?

2009 ◽  
Vol 5 (1) ◽  
pp. 341-367 ◽  
Author(s):  
A. Ngomanda ◽  
A. Chepstow-Lusty ◽  
M. Makaya ◽  
C. Favier ◽  
P. Schevin ◽  
...  
Keyword(s):  
Environmental History ◽  
Late Holocene ◽  
Environmental Changes ◽  
Elaeis Guineensis ◽  
Coastal Region ◽  
Climatic Conditions ◽  
Rapid Decline ◽  
Pollen Record ◽  
Secondary Forests ◽  
Equatorial Africa

Abstract. Past vegetation and climate changes reconstructed using two pollen records from Lakes Maridor and Nguène, Gabon, provide new insights into the environmental history of western equatorial African rainforests during the last 4500 cal yr BP. The Lake Maridor pollen record indicates that the coastal savannas of western equatorial Africa did not exist during the mid-Holocene and instead the region was covered by evergreen rainforests. In the Lake Nguène pollen record, a rapid decline of hygrophilous evergreen rainforest occurred around 4000 cal yr BP, synchronously with grassland expansion around Lake Maridor. The establishment of coastal savannas in Gabon suggests decreasing humidity at the onset of the late Holocene. The marked reduction in evergreen rainforest and subsequent savanna expansion was associated with the colonization of secondary forests dominated by the palm, Elaeis guineensis, in the coastal region and the shrub, Alchornea cordifolia, further inland. A return to wetter climatic conditions from about 1400 cal yr BP led to the renewed spread of evergreen rainforest inland, whereas a forest-savanna mosaic still persists in the coastal region. There is no evidence to suggest that the major environmental changes observed are driven by human impact.

scholarly journals Late-Holocene landscape evolution and human presence in the northern Danube delta (Chilia distributary lobes)

The Holocene ◽  
2021 ◽  
pp. 095968362110191
Author(s):  
Luminița Preoteasa ◽  
Alfred Vespremeanu-Stroe ◽  
Anca Dan ◽  
Laurențiu Țuțuianu ◽  
Cristian Panaiotu ◽  
...  
Keyword(s):  
Middle Ages ◽  
Economic History ◽  
Late Holocene ◽  
Environmental Changes ◽  
Land Use Changes ◽  
Sedimentary Facies ◽  
The Black Sea ◽  
Danube Delta ◽  
Human Presence ◽  
Historical Texts

This paper documents the Late-Holocene environmental changes and human presence in the northern Danube delta using a multidisciplinary approach that combines geoscientific data with archaeological findings, historical texts, and maps. It follows the formation and progression of the Chilia distributary and the reconfiguration of socioeconomic activities. Sedimentary facies identified on five new cores by changes in texture properties, magnetic susceptibility, geochemistry, and macro- and microfauna composition together with the newly obtained chronology constrain the complex evolution of the Chilia branch as filling in a long-lasting bay and then of a giant lagoon (Thiagola) which covered most of the northern delta since the Old Danube lobe inception (ca. 7500 yrs BP) till modern Chilia development. It initiated during the Greek Antiquity (ca. 2500 yrs ar BP) at the delta apex, while in Roman times (ca. 1800 yrs BP) it pursued its slow flowing into the vast Thiagola Lagoon. The most dramatic transformations occurred in the last 800 years when the river passed east of the Chilia promontory, rapidly went through the present-day Matița-Merhei basin (several decades), and created its first open-sea outlet. Solid discharge increased in two distinct periods, once in the Middle Ages (ca. 750 yrs BP) and then in the Modern Period (ca. 150 yrs BP) due to human-induced land-use changes in the Danube watershed. The chronology of the cultural remains on the pre-deltaic Chilia promontory and the multiproxy analysis of a sediment core retrieved nearby downstream suggest the terrestrial connection of the island with the mainland in ancient times. The hitherto contended issue of the old Thiagola Lagoon and its location are redefined here, as are the original identifications of ancient and medieval toponyms and hydronyms, especially for Chilia-Licostomo, Byzantine, Genoese, Moldavian, Ottoman, and Russian trading point of great importance in the political and economic history of the Black Sea and neighboring regions.

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