Vegetation Dynamics of Central Yamal in the Late Glacial and the Holocene (Based on Paleobotanical Materials from Peat Deposits of the Yuribei River Valley)

Abstract

A comprehensive paleoecological study of permafrost peat deposits from three locations in the middle reaches of the Yuribei River in the subzone of modern subarctic shrub tundra of the Yamal Peninsula has been performed. Based on the results of palynological and carpological methods and of radiocarbon dating, the changes in regional and local vegetation and climatic conditions of Central Yamal in the Late Glacial and the Postglacial periods are reconstructed. It is found that shrubby tundra with Betula nana was widespread in this area under climatic conditions close to modern ones in the Younger Dryas about 12.6–11.7 cal ka BP. The penetration of tree species (Betula sect. Betula, Picea obovata, and Larix sibirica) and accompanying boreal herbaceous plants began due to more favorable climatic conditions during the Early Holocene warming about 10.2–9.7 cal ka BP. The most favorable conditions for the growth of birch tree, larch, and spruce existed in Central Yamal in the Early and the Middle Holocene in the range of 10.2–4.4 cal ka BP. At that time, open woodlands or even closed forests were common, and the climate was much warmer than the modern one. Forest vegetation degraded and open landscapes with tundra communities were formed at the end of the Middle Holocene (4.5–4.4 cal ka BP). The climatic conditions became similar to modern ones.