Subfossil Insects of the Kebezen Site (Altai Mountains): New Data on the Last Deglaciation Environment

Abstract

This paper focuses on insect remains found at the Kebezen site in the Altai mountains, Russia. The results obtained from the samples supplement the information about the natural environment in Altai during the degradation of the last glaciation. The age of the studied sediments, from 20,100 to 19,300 cal yr BP, corresponds to the beginning of the degradation of the last glaciation. Beetles, represented by 105 species from 21 families, predominate in the site. The data obtained about these insects show that at this time, in contrast to the dry steppes of the West Siberian Plain, spruce forests and alpine meadows were developed in the north-eastern Altai region, and the climate was cold and humid. During sedimentation, rapid changes in the ecological composition of beetles were observed: the full-fledged forest complex was simplified and only meadow, and near-water species remained, and then species associated with shrubs, moss turfs, and trees consistently appeared. Such changes could be associated with a catastrophic event such as a megaflood. © 2025 by the authors.