Ecological thresholds and patterns of millennial-scale climate variability: The response of vegetation in Greece during the last glacial period

Tzedakis, Polychronis C.; Frogley, Michael R.; Lawson, Ian T.; Preece, Richard C.; Cacho, Isabel; Abreu, Lucia de

doi:10.1130/g20118.1

Cited by 149 publications

(143 citation statements)

References 22 publications

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“…The reduction of oceanic heat transport (weakening or shut down of the AMOC; Böhm et al, 2014;Bond and Lotti, 1995;Bond et al, 1993;Broecker, 1994;Cacho et al, 2000Cacho et al, , 1999Chapman and Shackleton, 1999) led to significantly cooler Mediterranean SST's and climatic conditions in the Mediterranean region (e.g., Allen et al, 1999;Fletcher et al, 2010;Müller et al, 2011;Sánchez Goñi et al, 2002;Tzedakis, 2005;Tzedakis et al, 2004). According to Kwiecien et al (2009), a decreasing atmosphere-sea-surface thermal gradient of the Mediterranean Sea would have caused a reduction in the frequency and strength of storm tracks, which were responsible for an intensifying aridity in the eastern Mediterranean region.…”

Section: Abrupt Climate Changes During Mis 4-2mentioning

confidence: 99%

Abrupt climate and vegetation variability of eastern Anatolia during the last glacial

et al. 2015

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Abstract. Detailed analyses of the Lake Van pollen, Ca / K ratio, and stable oxygen isotope record allow the identification of millennial-scale vegetation and environmental changes in eastern Anatolia throughout the last glacial (∼ 111.5-11.7 ka BP). The climate of the last glacial was cold and dry, indicated by low arboreal pollen (AP) levels. The driest and coldest period corresponds to Marine Isotope Stage (MIS) 2 (∼ 28-14.5 ka BP), which was dominated by highest values of xerophytic steppe vegetation.Our high-resolution multi-proxy record shows rapid expansions and contractions of tree populations that reflect variability in temperature and moisture availability. These rapid vegetation and environmental changes can be related to the stadial-interstadial pattern of Dansgaard-Oeschger (DO) events as recorded in the Greenland ice cores. Periods of reduced moisture availability were characterized by enhanced occurrence of xerophytic species and high terrigenous input from the Lake Van catchment area. Furthermore, the comparison with the marine realm reveals that the complex atmosphere-ocean interaction can be explained by the strength and position of the westerlies, which are responsible for the supply of humidity in eastern Anatolia. Influenced by the diverse topography of the Lake Van catchment, more pronounced DO interstadials (e.g., DO 19, 14, 12 and 8) show the strongest expansion of temperate species within the last glacial. However, Heinrich events (HE), characterized by highest concentrations of ice-rafted debris (IRD) in marine sediments, cannot be separated from other DO stadials based on the vegetation composition in eastern Anatolia. In addition, this work is a first attempt to establish a continuous microscopic charcoal record for the last glacial in the Near East.It documents an immediate response to millennial-scale climate and environmental variability and enables us to shed light on the history of fire activity during the last glacial.

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Section: Abrupt Climate Changes During Mis 4-2mentioning

confidence: 99%

Abrupt climate and vegetation variability of eastern Anatolia during the last glacial

et al. 2015

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“…Tzedakis et al (2004) studied three pollen records from contrasting bioclimatic areas in Greece and demonstrated the importance of local topography and ecological thresholds in controlling the response of the vegetation to climate variability. The Lake Prespa catchment sustained temperate tree populations throughout the last glacial (Fig.…”

Section: Mediterranean Recordsmentioning

confidence: 99%

Climate variability over the last 92 ka in SW Balkans from analysis of sediments from Lake Prespa

Böhm²,

et al. 2014

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Abstract. The transboundary Lake Prespa (Albania/former Yugoslav Republic of Macedonia/Greece) has been recognized as a conservation priority wetland. The high biodiversity encountered in the catchment at present points to the refugial character of this mountainous region in the southwestern Balkans. A lake sediment core retrieved from a coring location in the northern part of the lake was investigated through sedimentological, geochemical, and palynological analyses. Based on tephrochronology, radiocarbon and electron spin resonance (ESR) dating, and cross correlation with other Northern Hemisphere records, the age model suggests that the basal part of core Co1215 reaches back to 92 ka cal BP. Here we present the responses of this midaltitude site (849 m a.s.l.) to climate oscillations during this interval and assess its sensitivity to millennial-scale variability. Endogenic calcite precipitation occurred in marine isotope stages (MIS) 5 and 1 and is synchronous with periods of increased primary production (terrestrial and/or lacustrine). Periods of pronounced phytoplankton blooms (inferred from green algae and dinoflagellate concentrations) are recorded in MIS 5 and MIS 1 and suggest that the trophic state and lake levels underwent substantial fluctuations. Three major phases of vegetation development are distinguished: the forested phases of MIS 5 and MIS 1 dominated by deciduous trees with higher temperatures and moisture availability, the open landscapes of MIS 3 with significant presence of temperate trees, and the pine-dominated open landscapes of MIS 4 and MIS 2 with lower temperatures and moisture availability. Our findings suggest significant changes in forest cover and landscape openness, as well as in the properties of the vegetation belts (composition and distribution) over the period examined. The study area most likely formed the upper limit of several drought-sensitive trees (temperate tree refugium) at these latitudes in the Mediterranean mountains.

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“…Climate models suggest that this spatial heterogeneity in the North Atlantic climate response was transmitted to the continental interior, with DO cycle temperature anomalies penetrating deeper into the continent than HE-associated cooling [Ganopolski and Rahmstorf, 2001;Zhang et al, 2014]. Pollen and stalagmite records from eastern and southern Europe reveal a pronounced variability in rainfall that coincided with DO cycles characterized by wetter conditions and lower wind stress during interstadials [Allen et al, 1999;Tzedakis et al, 2004;Fleitmann et al, 2009;Fletcher et al, 2010] BLACK SEA TEMPERATURE AND DO CYCLES 1 differences between HE and non-HE stadials, the detailed patterns of DO cycles and HE in the eastern Mediterranean region seem to be more ambiguous [Tzedakis et al, 2004;Fleitmann et al, 2009;Shumilovskikh et al, 2014]. Farther to the east, in the southeastern Asian climate domain, the significant influence of DO cycles and HE on the monsoonal system is evidenced through changes in precipitation and wind intensity, based on data reconstructed from Chinese stalagmites [Wang et al, 2001] and loess deposits [Sun et al, 2012].…”

Section: Introductionmentioning

confidence: 99%

Black Sea temperature response to glacial millennial‐scale climate variability

Wegwerth

Ganopolski

Ménot

et al. 2015

Geophysical Research Letters

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The Eurasian inland propagation of temperature anomalies during glacial millennial‐scale climate variability is poorly understood, but this knowledge is crucial to understanding hemisphere‐wide atmospheric teleconnection patterns and climate mechanisms. Based on biomarkers and geochemical paleothermometers, a pronounced continental temperature variability between 64,000 and 20,000 years ago, coinciding with the Greenland Dansgaard‐Oeschger cycles, was determined in a well‐dated sediment record from the formerly enclosed Black Sea. Cooling during Heinrich events was not stronger than during other stadials in the Black Sea. This is corroborated by modeling results showing that regular Dansgaard‐Oeschger cycles penetrated deeper into the Eurasian continent than Heinrich events. The pattern of coastal ice‐rafted detritus suggests a strong dependence on the climate background state, with significantly milder winters during periods of reduced Eurasian ice sheets and an intensified meridional atmospheric circulation.

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Ecological thresholds and patterns of millennial-scale climate variability: The response of vegetation in Greece during the last glacial period

Cited by 149 publications

References 22 publications

Abrupt climate and vegetation variability of eastern Anatolia during the last glacial

Abrupt climate and vegetation variability of eastern Anatolia during the last glacial

Climate variability over the last 92 ka in SW Balkans from analysis of sediments from Lake Prespa

Black Sea temperature response to glacial millennial‐scale climate variability

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