Holocene vegetation and climate changes in the North-Eastern Caucasus (pollen data from mountains and plain peatlands)

Abstract

Dagestan (North-Eastern part of the Caucasus) is characterized by a unique historical and environment development, however, there is little, if no, data on nature changes throughout the Holocene history of the region. In contrast to the much-studied neighboring Caucasus regions, Dagestan remains mostly unexplored from the standpoint of paleoecology. In 2017, we investigated a detailed radiocarbon-dated 185 cm peat sequence from the Shotota swamp located in the mountainous zone of Dagestan. Peat and soil deposits span most of the Holocene (about 9000 years), and they let us study vegetation history of the Eastern Caucasus for the first time. The results of the study show significant discrepancies in the timing and sequence of the expansion of tree species in the Holocene in comparison with Transcaucasia and the Western Caucasus. The second key study, an examination of a 270 cm peat sequence from Arkida swamp, formed in the second half of the Holocene, also provided new paleoenvironmental data on the south of the Caspian lowland. The vegetation of the flat parts of Dagestan, adjacent to the mountainous zone, has been dry and treeless for the last four thousand years, however, humidification fluctuations and vegetation changes were distinguished.

The Holocene paleoenvironmental history of Western Caucasus (Russia) reconstructed by multi-proxy analysis of the continuous sediment sequence from Lake Khuko

“…Moreover, as a rule, sediment accumulation rate estimates are based on a single date determination and therefore the chronological resolution of these reconstructions is very poor. While the recent papers by Ryabogina et al (2019Ryabogina et al ( , 2020 provide very detailed and comprehensive paleoenvironmental reconstruction, their study site is in the Dagestan Republic, where the climate significantly differs from the Western Caucasus.…”

“…Connor and Kvavadze, 2009; Joannin et al, 2014; Leroyer et al, 2016; Ryabogina et al, 2019), the Western Caucasus still largely remains unstudied. A recent review of publications devoted to the Caucasus presented in Solomina et al (2016a) demonstrates that available paleoenvironmental data represent the general trend of climate variability or are focused on local phenomena, while the chronological boundaries of even the most prominent climatic shifts within the Holocene remain unclear for Western Caucasus (Bliedtner et al, 2018; Efremov, 1991; Kvavadze and Efremov, 1996; Margalitadze, 1995; Messager et al, 2013, 2017; Moiseenko et al, 2012; Ryabogina et al, 2019, 2020; Serebryaniy et al, 1984). Most previous paleoclimate data (e.g.…”