Vegetation and Microtheriofauna Dynamics during the Late Glaciation and Holocene in the Yugyd-Va National Park

Abstract

The results of studies of the Late Pleistocene and Holocene spore–pollen spectra and the microtheriofauna of loose deposits of four cave localities located in the Shchuger and Kozhym river basins within the territory of the Yugyd-Va National Park on the western slope of the Subpolar Urals are discussed. Assessment of the age of sediments from the karst cavities was based on the data of AMS radiocarbon dating of mammalian bones. The speleogenic formations of the localities studied contain layers assigned to the final stage of the degradation of the Polar Ural (Late Valdai) glaciation (Middle to Late Dryas) and to the Preboreal, Boreal, and Subatlantic periods of the Holocene. Cryoxerophilous tundra species predominated (88.3%) in the fossil microtheriofauna assemblage identified for the Allerod. The Middle Dryas and Allerod, the cold and warm periods of the Late Glacial, respectively, were reflected by the spore–pollen spectra. The microtheriofauna on the western slope of the Subpolar Urals remained quite cryophilous by the end of the Late Dryas. The broad distribution of yernik thickets and goosefoot–gramineous–mixed herb assemblages during that time has been established. The vegetation of the western foothills of the Subpolar Urals consisted of grass–shrub tundra with sparse spruce trees during the Late Preboreal cooling period. The microtheriofauna community also had a tundra-like composition. The presence of dark coniferous taiga forests in the south of the Subpolar Urals and sparse spruce–birch forests with pine and dwarf birch in the undergrowth in the north of the area during the Boreal period has been established. The rodent fauna acquired a forest-like character by that time. Northern taiga dark coniferous forests of spruce with a significant admixture of pine developed on the western slope of the Subpolar Urals by the middle of the Subatlantic period, and the content of tundra elements in the stands increased by the end of this period. The microtheriofauna of the studied region had a typical forest appearance characteristic of all Late Holocene taiga communities in northeastern Europe.