Pollen-based reconstructions of vegetation and climate changes during the late Holocene in the southern Altai Mountains

The Holocene ◽  
2019 ◽  
Vol 29 (9) ◽  
pp. 1450-1458 ◽  
Author(s):  
Yunpeng Yang ◽  
Dongliang Zhang ◽  
Aizhi Sun ◽  
Wei Wang ◽  
Bo Lan ◽  
...  
Keyword(s):  
Late Holocene ◽  
Climate Changes ◽  
Altai Mountains ◽  
Pollen Data ◽  
Raised Bog ◽  
Increasing Trend ◽  
Surrounding Areas ◽  
Vegetation And Climate ◽  
Peat Area

We here preset a result of high-resolution pollen data of a lacustrine-peat sediment core from Yushenkule (YSKL) Peat, southern Altai Mountains, northwestern China. We aim to reconstruct the palaeovegetation and palaeoclimate variations in the southern Altai Mountains and further evaluate the role of autogenic process of the raised bog itself in driving the local vegetation dynamics. The pollen data of YSKL core-2 show two major vegetation stages in YSKL Peat area and the surrounding areas during the data-covering period. During the stage lasting from ~4870 to ~2550 cal. yr BP, regional vegetation was dominated by desert steppe and local vegetation in YSKL Peat was characterized by Artemisia-dominated mountain steppe. During the stage lasting from ~2550 to ~700 cal. yr BP, regional vegetation was characterized by Artemisia-dominated steppe and local vegetation in YSKL Peat was characterized by Cyperaceae-dominated wetland herbs. The Ar/Am ( Artemisia/Amaranthaceae) ratio-indicated moisture increasing trend of southern Altai Mountains can attribute to the combined effects of decreased temperature and increased precipitation. The lithologic transition from lake to peat of YSKL core-2 can be explained by invoking the variations in the areal extent of ice covers in the Altai Mountains.

scholarly journals Late Holocene plant and climate evolution at Lake Yoa, northern Chad: pollen data and climate simulations

2011 ◽  
Vol 7 (4) ◽  
pp. 1351-1362 ◽  
Author(s):  
A.-M. Lézine ◽  
W. Zheng ◽  
P. Braconnot ◽  
G. Krinner
Keyword(s):  
Late Holocene ◽  
Climate Changes ◽  
Direct Consequence ◽  
Atmospheric Model ◽  
Plant Distribution ◽  
Time Interval ◽  
Pollen Data ◽  
Tropical Plant ◽  
Climate Simulations ◽  
Dry Spell

Abstract. The discovery of groundwater-fed Lake Yoa (19.03° N, 20.31° E) in the hyperarid desert of northern Chad by the German research team ACACIA headed by S. Kröpelin provides a unique, continuous sedimentary sequence of late Holocene age available in the entire Saharan desert. Here we present pollen data and climate simulations using the LMDZ atmospheric model with a module representing the climatologically-relevant thermal and hydrological processes occurring above and beneath inland water surfaces to document past environmental and climate changes during the last 6000 cal yr BP. Special attention is paid to wind strength and direction, length and amplitude of the rainy season, and dry spell occurrence, all of which are of primary importance for plant distribution and pollen transport. In addition to climate changes and their impact on the natural environment, anthropogenic changes are also discussed. Two main features can be highlighted: (1) the shift from an earlier predominantly monsoonal climate regime to one dominated by northern Mediterranean fluxes that occurred after 4000 cal yr BP. The direct consequence of this was the establishment of the modern desert environment at Yoa at 2700 cal yr BP. (2) Changes in climate parameters (simulated rainfall amount and dry spell length) between 6 and 4000 cal yr BP were comparatively minor. However, changes in the seasonal distribution of precipitation during this time interval dramatically affected the vegetation composition and were at the origin of the retreat of tropical plant communities from Lake Yoa.

Climate change and human disturbance of fynbos vegetation during the late Holocene at Princess Vlei, Western Cape, South Africa

The Holocene ◽  
2011 ◽  
Vol 21 (7) ◽  
pp. 1137-1149 ◽  
Author(s):  
F.H. Neumann ◽  
L. Scott ◽  
M.K. Bamford
Keyword(s):  
Anthropogenic Disturbance ◽  
Late Holocene ◽  
Climate Changes ◽  
Western Cape ◽  
Radiocarbon Dates ◽  
The Core ◽  
Pollen Types ◽  
Hydrological System ◽  
Vegetation And Climate ◽  
Floating Mat

Pollen analysis of a core in Princess Vlei in the Fynbos Biome near Cape Town gives a 4150 year record of vegetation and climate changes followed by disturbance by colonial settlers since c. 300 years ago. Their impact replaced climate as a major factor in changing the vegetation. The chronology is based on eight radiocarbon dates. Pollen types such as Restionaceae, Ericaceae, and Proteaceae reflect changes in fynbos. Pollen indicators at the bottom of the core suggest drier conditions followed by an increase in Morella, Cyperaceae and Carpacoce pollen, which might indicate moist conditions c. 3400–2600 cal. yr BP. Drier conditions prevail c. 2600–1900 cal. yr BP. Apparent light disturbance after c. 2000 cal. yr BP might be attributed to Khoi herders. Deeper water and damp surroundings are indicated c. 1900–1000 cal. yr BP. The top of the core shows an increase of Poaceae while Restionaceae decrease with anthropogenic disturbance, including the introduction of neophytes such as Pinus ( c. 300 years ago) and Zea mays. Charcoal percentages point to intense fires after the arrival of the Europeans. Water between 105 and 75 cm indicates the development of a floating mat resulting from changes in the hydrological system possibly connected to disturbances by settlers.

First high-resolution dated records of vegetation and climate changes on the Lake Baikal northern shore in the middle-late Holocene

2006 ◽  
Vol 411 (1) ◽  
pp. 1331-1335 ◽  
Author(s):  
E. V. Bezrukova ◽  
A. V. Belov ◽  
A. A. Abzaeva ◽  
P. P. Letunova ◽  
L. A. Orlova ◽  
...  
Keyword(s):  
High Resolution ◽  
Lake Baikal ◽  
Late Holocene ◽  
Climate Changes ◽  
Northern Shore ◽  
Vegetation And Climate

Vegetation changes and associated climatic changes in the southern Altai Mountains within China during the Holocene

The Holocene ◽  
2016 ◽  
Vol 27 (5) ◽  
pp. 683-693 ◽  
Author(s):  
Zhaodong Feng ◽  
Aizhi Sun ◽  
Nurbayev Abdusalih ◽  
Min Ran ◽  
Alishir Kurban ◽  
...  
Keyword(s):  
Climatic Change ◽  
North Atlantic ◽  
Late Holocene ◽  
Mean Annual Precipitation ◽  
Mean Annual Temperature ◽  
Mountain Range ◽  
Altai Mountains ◽  
Pollen Data ◽  
The Holocene ◽  
The Pacific

The location of the Altai Mountains at the limits of both the Pacific and Atlantic influences implies that this mountain range is an important climatic boundary. Based on pollen data of 188 samples of a 390-cm core from Narenxia Peat in the southern Altai with a chronologic support of 11 accelerator mass spectrometry (AMS) dates, we reconstructed the Holocene climatic change at Narenxia Peat. The reconstruction revealed five stages of climatic change: a cold and dry latest deglacial (prior to ~11,500 cal. yr BP), a warm and wet early-Holocene (~11,500 to ~7000 cal. yr BP), a considerably cooled and dried middle Holocene (~7000 to ~4000 cal. yr BP), a resumed warm and wet late-Holocene (~4000 to ~1200 cal. yr BP), and a relatively cool and dry latest Holocene (past ~1200 years). The reconstructions of mean annual temperature (MAT) and mean annual precipitation (MAP) from Narenxia Peat well resemble the reconstructions of North Atlantic Oscillations (NAO) and El Niño–Southern Oscillations (ENSO). The resemblance implies that the Holocene millennial-scale changes in MAT and MAP in the Altai might have been causally associated with the variations in NAO and ENSO.

Vegetation and climate changes during the Eemian interglacial in Central and Eastern Europe: comparative analysis of pollen data

Boreas ◽  
2005 ◽  
Vol 34 (2) ◽  
pp. 207-219 ◽  
Author(s):  
Andrei Velichko ◽  
Elena Novenko ◽  
Valentina Pisareva ◽  
Ella Zelikson ◽  
Tatjana Boettger ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Eastern Europe ◽  
Climate Changes ◽  
Central And Eastern Europe ◽  
Pollen Data ◽  
Vegetation And Climate ◽  
Eemian Interglacial

scholarly journals Holocene Vegetation and Climate Dynamics in the Altai Mountains and Surrounding Areas

2018 ◽  
Vol 45 (13) ◽  
pp. 6628-6636 ◽  
Author(s):  
Xiaozhong Huang ◽  
Wei Peng ◽  
Natalia Rudaya ◽  
Eric C. Grimm ◽  
Xuemei Chen ◽  
...  
Keyword(s):  
Climate Dynamics ◽  
Altai Mountains ◽  
Surrounding Areas ◽  
Vegetation And Climate

scholarly journals Palynological evidence for gradual vegetation and climate changes during the African Humid Period termination at 13°N from a Mega-Lake Chad sedimentary sequence

2013 ◽  
Vol 9 (1) ◽  
pp. 223-241 ◽  
Author(s):  
P. G. C. Amaral ◽  
A. Vincens ◽  
J. Guiot ◽  
G. Buchet ◽  
P. Deschamps ◽  
...  
Keyword(s):  
Climate Changes ◽  
Environmental Changes ◽  
Mean Annual Precipitation ◽  
Sedimentary Sequence ◽  
Pollen Data ◽  
Climate Conditions ◽  
Lake Chad ◽  
Sahel Region ◽  
Vegetation And Climate ◽  
Humid Period

Abstract. Located at the transition between the Saharan and Sahelian zones, at the center of one of the largest endorheic basins, Lake Chad is ideally located to record regional environmental changes that occurred in the past. However, until now, no Holocene archive was directly cored in this lake. In this paper, we present pollen data from the first sedimentary sequence collected in Lake Chad (13° N; 14° E; Sahel region). Dated between ca. 6700 and ca. 5000 cal yr BP, this record is continuous and encompasses part of the termination of the African Humid Period (AHP). Vegetation reconstructions are based on standard analyses of pollen diagrams and are strengthened by quantitative approaches. Potential biomes are reconstructed using the biomization method and mean annual precipitation (Pann) is estimated using the modern analogues technique. Results show that, between ca. 6700 and ca. 6050 cal yr BP, a vegetation close to humid woodland or humid savanna, including elements currently found further southward, thrived in the vicinity of the Mega-Lake Chad in place of the modern dry woodland, steppe and desert vegetation. At the same time, montane forest populations extended further southward on the Adamawa Plateau. The high abundance of lowland humid pollen taxa, particularly of Uapaca, is interpreted as the result of a northward migration of the corresponding plants during the AHP. This preferential zonal occurrence of these taxa in Lake Chad Basin (LCB) (rather than extrazonal) is driven by more humid local and regional climate conditions at this latitude, as shown by mean Pann estimated values of ca. 800 (−400/+700) mm during this period. However, we cannot rule out that an increase of the Chari–Logone inputs into the Mega-Lake Chad might have also contributed to control the abundance of these taxa. Changes in the structure and floristic composition of the vegetation towards more open and drier formations occurred after ca. 6050 cal yr BP, following a decrease in mean Pann estimates to approximately 600 (−230/+600) mm. But, the constant significant presence of lowland humid taxa until ca. 5000 cal yr BP, contemporaneous with a slight increase in steppic taxa, demonstrates that at this date, the modern vegetation was not yet established in the vicinity of Lake Chad. Our data indicate that between ca. 6700 and ca. 5000 cal yr BP vegetation and climate changes must have occurred progressively, but that century-scale climate variability was superimposed on this long-term mid-Holocene drying trend as observed around ca. 6300 cal yr BP, where pollen data indicate more humid conditions.

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