Evidence of a late glacial warming event and early Holocene cooling in the southern Brazilian coastal highlands

2017 ◽  
Vol 89 (1) ◽  
pp. 90-102 ◽  
Author(s):  
Hermann Behling ◽  
Marcelo Accioly Teixeira de Oliveira
Keyword(s):  
Late Glacial ◽  
Dry Season ◽  
Atlantic Rain Forest ◽  
Pollen Record ◽  
Grassland Vegetation ◽  
History Of Vegetation ◽  
Tree Ferns ◽  
Dry Conditions ◽  
History Of ◽  
Vegetation And Climate

AbstractA high-resolution pollen record of the Atlantic rain forest (ARF) biome from the coastal Serra do Tabuleiro mountains of southern Brazil documents an 11,960 yr history of vegetation and climate change. A marked expansion of Weinmannia into the grassland vegetation marks the latter part of the Younger Dryas, reflecting warm and relatively wet conditions. Between 11,490 and 9110 cal yr BP, grasslands became dominant again, indicating a long cold and dry phase, probably in response to the stronger influence of cold South Atlantic seawater and to Antarctic cold fronts. Between 9110 and 2640 cal yr BP, four distinct phases with strong or moderate expansions of different ARF biome taxa were recorded, reflecting warmer and relatively dry conditions with changes in rainfall and length of the annual dry season. After 2640 cal yr BP, the modern ARF biome became established with high amounts of ferns, reflecting somewhat cooler and wetter conditions with a reduced annual dry season. In particular, after 1000 cal yr BP tree ferns increased, reflecting wetter conditions with no dry season.

Late Quaternary vegetation, climate, and fire history of the Southeast Atlantic Coastal Plain based on a 30,000-yr multi-proxy record from White Pond, South Carolina, USA

2019 ◽  
Vol 91 (2) ◽  
pp. 861-880 ◽  
Author(s):  
Teresa R. Krause ◽  
James M. Russell ◽  
Rui Zhang ◽  
John W. Williams ◽  
Stephen T. Jackson
Keyword(s):  
South Carolina ◽  
Vegetation Change ◽  
Fire History ◽  
Late Quaternary ◽  
Late Glacial ◽  
Atlantic Coastal Plain ◽  
Proxy Records ◽  
Dry Conditions ◽  
History Of ◽  
Mississippian Culture

AbstractThe patterns and drivers of late Quaternary vegetation dynamics in the southeastern United States are poorly understood due to low site density, problematic chronologies, and a paucity of independent paleoclimate proxy records. We present a well-dated (15 accelerator mass spectrometry14C dates) 30,000-yr record from White Pond, South Carolina that consists of high-resolution analyses of fossil pollen, macroscopic charcoal, andSporormiellaspores, and an independent paleotemperature reconstruction based on branched glycerol dialkyl tetraethers. Between 30,000 and 20,000 cal yr BP, openPinus-Piceaforest grew under cold and dry conditions; elevatedQuercusbefore 26,000 cal yr BP, however, suggest warmer conditions in the Southeast before the last glacial maximum, possibly corresponding to regionally warmer conditions associated with Heinrich event H2. Warming between 19,700 and 10,400 cal yr BP was accompanied by a transition from conifer-dominated to mesic hardwood forest.Sporormiellaspores were not detected and charcoal was low during the late glacial period, suggesting megaherbivore grazers and fire were not locally important agents of vegetation change.Pinusreturned to dominance during the Holocene, with step-like increases inPinusat 10,400 and 6400 cal yr BP, while charcoal abundance increased tenfold, likely due to increased biomass burning associated with warmer conditions. Low-intensity surface fires increased after 1200 cal yr BP, possibly related to the establishment of the Mississippian culture in the Southeast.

scholarly journals Late Glacial and Holocene changes in vegetation cover and climate in southern Siberia derived from a 15 kyr long pollen record from Lake Kotokel

2009 ◽  
Vol 5 (1) ◽  
pp. 127-151 ◽  
Author(s):  
P. E. Tarasov ◽  
E. V. Bezrukova ◽  
S. K. Krivonogov
Keyword(s):  
Late Glacial ◽  
Time Interval ◽  
Pollen Record ◽  
Time Intervals ◽  
Southern Siberia ◽  
Noticeable Increase ◽  
Modern Analogue ◽  
Quantitative Characteristics ◽  
Late Glacial And Holocene ◽  
Vegetation And Climate

Abstract. In this study a radiocarbon-dated pollen record from Lake Kotokel (52°47´ N, 108°07´ E, 458 m a.s.l.) located in southern Siberia east of Lake Baikal was used to derive quantitative characteristics of regional vegetation and climate since about 15 kyr BP (1 kyr=1000 cal. yr) until today. Quantitative reconstruction of the late glacial vegetation and climate dynamics suggests that open steppe and tundra communities predominated in the study area prior to ca. 13.5 kyr BP and again during the Younger Dryas interval, between 12.8 and 11.6 kyr BP. The pollen-based climate reconstruction suggests lower-than-present mean January (~–38°C) and July (~12°C) temperatures and annual precipitation (~270–300 mm) values during these time intervals. Boreal woodland replaced the primarily open landscape around Kotokel three times at about 14.8–14.7 kyr BP, during the Allerød Interstadial between 13.3–12.8 kyr BP and with the onset of the Holocene interglacial between 11.5 and 10.5 kyr BP, presumably in response to a noticeable increase in precipitation, and in July and January temperatures. The maximal spread of the boreal forest (taiga) communities in the region is associated with a warmer and wetter-than-present climate (Tw~17–18°C, Tc~–19°C, Pann~500–550 mm) occurred ca.\\ 10.8–7.3 kyr BP. During this time interval woody vegetation covered more than 50% of the area within a 21×21 km window around the lake. The pollen-based best modern analogue reconstruction suggests a decrease in woody cover percentages and in all climatic variables about 7–6.5 kyr BP. Since that time our results demonstrate gradual decrease in precipitation and mean January temperature towards their present-day values in the region around Lake Kotokel.

scholarly journals Vegetation and climate dynamics in Khyber Pakhtunkhwa (NW Pakistan), inferred from the pollen record of the Kabal Valley in Swat District during the last 3300 years

2019 ◽  
Vol 59 (1) ◽  
pp. 145-163
Author(s):  
Farooq Jan ◽  
Lisa Schüler ◽  
Fayaz Asad ◽  
Hermann Behling
Keyword(s):  
Vegetation History ◽  
Agricultural Activity ◽  
Pollen Record ◽  
Conifer Forest ◽  
Khyber Pakhtunkhwa ◽  
Hindu Kush ◽  
History Of ◽  
Khyber Pakhtunkhwa Province ◽  
Trees And Shrubs ◽  
Vegetation And Climate

Abstract We present a pollen-based palaeoenvironmental reconstruction of the past 3300 years in the Kabal Valley of Swat District in the Hindu Kush mountains of Khyber Pakhtunkhwa Province, north-western Pakistan. We studied the pollen record from 38 samples taken from a 150 cm long radiocarbon-dated sediment core in order to analyse the vegetation history of the area. Only the upper 76 cm of the core, with 20 samples recording the last 3300 years, had sufficiently preserved pollen. Conifers such as Pinus, Picea, Abies, Cedrus and Taxus, and herbs belonging to Poaceae, Cyperaceae and Amaranthaceae were found consistently throughout the period, at varying abundance. The vegetation reconstruction revealed that Cyperaceae and Poaceae dominated the conifers from 3300 to 300 cal yr BP. The decrease in herbaceous vegetation (mainly Poaceae) from 2400 to 1500 cal yr BP, and its increase from 1500 to 1200 cal yr BP, indicate contraction followed by expansion of grassland in the Kabal Valley of Swat, pointing to corresponding dry-cool and wet-warm periods. Herbs were abundant in most samples from 900 to 300 cal yr BP. This change from conifer forest to open grassland can be attributed to the more pronounced impact of widespread deforestation, agricultural activity and a drier summer climate. Evergreen trees and shrubs such as Oleaceae, Myrtaceae, Moraceae species, Juglans and Dodonaea dominated and were constant from 2400 cal yr BP to the present. Conifers such as Pinus, Taxus, Picea, Abies and Cedrus were frequent in the study area from 300 cal yr BP to the present. Today these conifers occur mostly in mixed coniferous forests at higher elevation in the alpine area.

scholarly journals Late-Glacial and Postglacial Vegetation and Climate of Jackson Hole and the Pinyon Peak Highlands, Wyoming

1985 ◽  
Vol 9 ◽  
pp. 44-49
Author(s):  
Cathy Barnosky
Keyword(s):  
Rocky Mountains ◽  
National Park ◽  
Vegetation History ◽  
Late Quaternary ◽  
Late Glacial ◽  
Glacial Refugia ◽  
Northern Rocky Mountains ◽  
Jackson Hole ◽  
History Of ◽  
Vegetation And Climate

The late-Quaternary vegetation history of the northern Rocky Mountains has thus far been inferred largely from isolated records. These data suggest that conifer forests were established early in postglacial time and were little modified thereafter. The similarity of early postglacial vegetation to modern communities over broad areas gives rise to two hypotheses: (1) that glacial refugia were close to the ice margin, and (2) that vegetation soon colonized the deglaciated areas and has been only subtly affected by climatic perturbations since that time. It is the goal of this project to test these two hypotheses in the region of Grand Teton National Park.

scholarly journals HISTORY OF VEGETATION AND CLIMATE OF THE OKINSKY PLATEAU (EASTERN SAYAN) IN THE HOLOCENE

2021 ◽  
pp. 17-19
Author(s):  
E. V. Volchatova ◽  
E. V. Bezrukova ◽  
A. A. Amosova ◽  
Maarten van Hardenbroek ◽  
N. V. Kulagina
Keyword(s):  
The Holocene ◽  
History Of Vegetation ◽  
History Of ◽  
Eastern Sayan ◽  
Vegetation And Climate

A record of late-Holocene environmental change from southern New England, USA

2011 ◽  
Vol 76 (3) ◽  
pp. 314-318 ◽  
Author(s):  
W. Wyatt Oswald ◽  
David R. Foster
Keyword(s):  
New England ◽  
Late Holocene ◽  
Climatic Variability ◽  
Organic Content ◽  
Pollen Record ◽  
Southern New England ◽  
Ecological Changes ◽  
Dry Conditions ◽  
History Of ◽  
The Town

AbstractAnalyses of a sediment core from Little Pond, located in the town of Bolton, Massachusetts, provide new insights into the history of environmental and ecological changes in southern New England during the late Holocene. Declines in organic content and peaks in the abundance of Isoetes spores indicate reduced water depth at 2900–2600, 2200–1800, and 1200–800 calibrated years before present (cal yr BP), generally consistent with the timing of dry conditions in records from elsewhere in the northeastern United States. The Little Pond pollen record features little change over the last 3000 yr, indicating that the surrounding vegetation was relatively insensitive to these periods of drought. The 1200–800 cal yr BP dry interval, however, coincides with increased abundance of Castanea pollen, suggesting that the expansion of Castanea in southern New England may have been influenced by late-Holocene climatic variability.

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