Vegetation dynamics in the Northeastern Mediterranean region during the past 23 000 yr: insights from a new pollen record from the Sea of Marmara

V Valsecchi,M F Sanchez Goñi,L Londeix

doi:10.5194/cp-8-1941-2012

Abstract

Abstract. High-resolution pollen analysis of core MD01-2430 from the Sea of Marmara (40°47.81' N, 27°43.51' E) allows us to reconstruct the vegetation response to climatic changes during the past 23 cal ka in the Northeastern Mediterranean. Variation in mesic/temperate forest cover indicates major climatic shifts connected to Heinrich Stadial 1, Bölling-Allerød, Younger Dryas and to the onset of the Holocene. Pollen–anthropogenic indicator approach was used to recognize human-induced landscape changes in the Sea of Marmara. The pollen-inferred onset of the Holocene occurs at ca. 11.5 cal ka, indicating that the Northeastern Mediterranean region represents a transitional zone where higher moisture availability supported an earlier forest expansion than the borderlands of the Aegean Sea and Black Sea. Two major forest retreats occurred during the Holocene at ca. 5.5 and 2.1 cal ka. The Holocene forest setbacks are in phase with previously published alkenone-inferred sea-surface temperature decreases in the Sea of Marmara reconstructed from the same core. Our new pollen record testifies the sensitivity of Mediterranean forests to changes in moisture availability, which is driven by changes in high-latitude atmospheric processes (North Atlantic Oscillations and/or Siberian High).

Highlights

This type of vegetation indicates a cold and rather dry climate during a period that falls in the Last Glacial Maximum (LGM, Mix et al, 2001), as suggested by other records from the Sea of Marmara (Mudie et al, 2007)
We have shown a wet to dry trend within the HS1 in the Sea of Marmara region and drier and colder conditions than during the LGM, just as was found in the Western Mediterranean (Naughton et al, 2007; Fletcher et al, 2010a), confirming that western storm tracks penetrated during the LGM
Our record does not show a time lag during the Holocene reforestation, pointing to the fact that northern Anatolia lies on a transitional area compared to the Near East or continental areas, where drought was a limiting factor up to 9–8 cal ka

Summary

Introduction

Palynological studies carried out in the Northeastern Mediterranean region have shown that the vegetation of this region was sensitive to the climatic variations of the North Atlantic high latitudes (i.e. Heinrich events and DansgaardOeschger cycles) (Geraga et al, 2005; Fletcher et al, 2010a) as well as to short climatic shifts during the Holocene (Wijmstra, 1969; Roberts et al, 2001; Lawson et al, 2005; Tzedakis, 2007; Kotthoff et al, 2008a, 2011; Pross et al, 2009). Valsecchi et al.: Vegetation dynamics in the Northeastern Mediterranean region during the past 23 000 yr between the Aegean Sea and the Black Sea and may, be a key area to clarify the timing of early Holocene reforestation in the Northeastern Mediterranean region. The first overview of the vegetation dynamics around the Sea of Marmara for the past 33 ka was based on low-resolution pollen records that suggested colder and drier pre- and post- Last Glacial Maximum (LGM) conditions, a warm and humid early Holocene, and sustained anthropogenic impact on vegetation from 3.5 14C kyr BP onwards (Mudie et al, 2002, 2007). Unfavourable climatic conditions (e.g. dry/cold episodes) were impacting prehistoric societies causing their collapse (Weiss et al, 1993; Vermoere et al, 2002)

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Discussion

Conclusion