Impact of climate changes on vegetation and human societies during the Holocene in the South Caucasus (Vanevan, Armenia): A multiproxy approach including pollen, NPPs and brGDGTs

• Published in: Quaternary Science Reviews
• Main Authors: Robles, Mary, Peyron, Odile, Brugiapaglia, Elisabetta, Ménot, Guillemette, Dugerdil, Lucas, Ollivier, Vincent, Ansanay-Alex, Salomé, Develle, Anne-Lise, Tozalakyan, Petros, Meliksetian, Khachatur, Sahakyan, Kristina, Sahakyan, Lilit, Perello, Bérengère, Badalyan, Ruben, Colombié, Claude, Joannin, Sébastien
• Other Authors: Institut des Sciences de l'Evolution de Montpellier (UMR ISEM), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de recherche pour le développement IRD : UR226-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), Università degli Studi del Molise = University of Molise (UNIMOL), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement Lyon (LGL-TPE), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire méditerranéen de préhistoire Europe-Afrique (LAMPEA), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Ministère de la Culture (MC), Environnements, Dynamiques et Territoires de la Montagne (EDYTEM), Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS), National Academy of Sciences of the Republic of Armenia Yerevan (NAS RA), Centre National de la Recherche Scientifique (CNRS), ARCHEORIENT - Environnements et sociétés de l'Orient ancien (Archéorient), Université Lumière - Lyon 2 (UL2)-Centre National de la Recherche Scientifique (CNRS), Institute of Archaeology and Ethnography of National Academy of Sciences of Armenia (IAE NAS RA)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2022
• Subjects: Vegetation dynamics; Human impact; Agriculture; Water level changes; Paleoclimate; Arid climate events; Transfer functions; XRF; [SHS.ARCHEO]Humanities and Social Sciences/Archaeology and Prehistory; [SDV.EE.BIO]Life Sciences [q-bio]/Ecology; environment/Bioclimatology; North Atlantic; North Atlantic oscillation
• Online Access: https://hal-insu.archives-ouvertes.fr/insu-03710173; https://hal-insu.archives-ouvertes.fr/insu-03710173/document; https://hal-insu.archives-ouvertes.fr/insu-03710173/file/Robles%20et%20al.,%202021%20QSR%2009-12-21.pdf; https://doi.org/10.1016/j.quascirev.2021.107297

International audience Relationships between steppe vegetation, human practices and climate changes in the past are crucial to disentangle human development in Eurasia. In this frame, our study investigates (1) modern pollen-vegetation relationships and (2) changes in vegetation, human activity and climate in the Holocene record of Vanevan peat (south-eastern shore of Lake Sevan, Armenia), using a multiproxy approach including sediment geochemistry (XRF), pollen, Non-Pollen Palynomorphs (NPPs), and branched Glycerol Dialkyl Glycerol Tetraethers (brGDGTs). Climate reconstructions are provided by (1) water-level changes, (2) brGDGTs, and (3) pollen transfer functions (multi-method approach: Modern Analogue Technique, Weighted Averaging Partial Least Squares regression, Random Forest, and Boosted Regression Trees). Modern pollen assemblages are selected along an altitudinal transect in Armenia. They show a dominance of Chenopodiaceae in semi-desert/steppe regions while meadows steppes, subalpine, and alpine meadows are dominated by Poaceae. Past vegetation is characterized by steppes dominated by Poaceae surrounded during the Mid-Holocene (8200-4200 a cal BP) by scarce open woodlands. Humans have influenced the local vegetation, mainly through their agricultural practices present since 5200 a cal BP with several intensification steps. Our reconstruction indicates a climate shift from a cold and arid Early Holocene toward a warmer and more humid Mid-Late Holocene. An aridification trend marks the last 5000 years causing a drop in water level, which allowed humans to live and cultivate on Lake Sevan shores. Arid events are recorded at 6.2 ka, 5.2 ka, 4.2 ka and 2.8 ka a cal BP, which are commonly related to multi-centennial-scale variations of Westerlies activity (North Atlantic Oscillation). Through our temperature reconstruction, we can assign (1) the 5.2 and 2.8 ka events as being cold and probably related to a strong Siberian High, and (2) the 4.2 ka event as being warm associated with high Arabian subtropical ...