Holocene vegetation and hydroclimatic dynamics in SE Lithuania - Implications from a multi-proxy study of the Čepkeliai bog

Summary, in English

Due to the scarcity of reliable palaeoecological and climatic proxy records from the Eastern Baltic covering the Holocene, there has been increased interest for multi-proxy studies in the region to detect local to regional environmental changes. The Čepkeliai wetland complex, SE Lithuania, provides an uninterrupted Holocene sediment sequence, which is used here to reconstruct palaeoenvironmental history in the southern part of the Eastern Baltic. High-resolution lithological (LOI, magnetic susceptibility), palaeobotanical (pollen, plant macrofossil, tree rings), isotopic (¹⁴C) and geochemical data were employed to reconstruct the peculiarities of vegetation and hydroclimate dynamics, as well as to discuss results in a local to regional context. Temporal lags of environmental reactions to Holocene climatic warming were recorded both in lithostratigraphical and biostratigraphical data, thus confirming regional significance of this phenomenon. A deep meso- to eutrophic basin - influenced by high surface runoff and surrounded by early boreal forest - existed at the site until about 11,300 cal BP. Thereafter, immigration of thermophylous taxa such as Ulmus (since 10,700-10,800 cal BP), Corylus (since 10,400-10,300 cal BP), Tilia and Quercus (after 9500 cal BP) as well as changes in the limnic environment point to an amelioration of the environmental situation, i.e. to a predominance of a warm and dry climatic regime. Instability of palaeobotanical and lithological records suggests that environmental anomalies of the Early Holocene occurred at about 11,200-11,000 cal BP, 10,600-10,300 cal BP, and 8200-7800 cal BP. These anomalies are thus contemporaneous with the pronounced climatic shifts (i.e. dry and cool intervals) known at the continental scale. An expansion of Picea was facilitated by the 8200-7800 cal BP climatic shift whereas early establishment of Alnus glutinosa suggests an onset of a wet interval (10,200 cal BP) which was previously unknown in the area. The stepwise lowering of the water table noted at about 7300-7200 and 6600-6700 cal BP, with the termination of the lake-phase and change to telmatic environment after 6100 cal BP, proves the positive reaction of the site to the dry climatic reversals of the Middle Holocene. Following the decay of the broad-leaved thermophilous forest after 4500 cal BP, a cold climatic reversal favored the formation of a diverse mosaic-like vegetation which was then replaced by homogenous Pinus-Picea vegetation after 3400 cal BP. The climatic and site-specific factors have been playing a leading role in the development of the site whereas signals of human interference remain negligible.

• Författare: Migle Stančikaite; Laura Gedminiene; Johannes Edvardsson; Markus Stoffel; Christophe Corona; Gražyna Gryguc; Domas Uogintas; Rimante Zinkute; Žana Skuratovič; Ričardas Taraškevičius
• Avdelning/ar: BECC: Biodiversity and Ecosystem services in a Changing Climate; Kvartärgeologi
• Publiceringsår: 2019
• Språk: Engelska
• Sidor: 219-239
• Publikation/Tidskrift/Serie: Quaternary International
• Volym: 501
• Länkar: http://dx.doi.org/10.1016/j.quaint.2017.08.039
• Dokumenttyp: Artikel i tidskrift
• Förlag: Pergamon Press Ltd.
• Ämne: Geology
• Nyckelord: Holocene; Hydroclimate dynamics; Lithuania; Multi-proxy data; Vegetation history
• Status: Published
• ISBN/ISSN/Övrigt: ISSN: 1040-6182