Causes of fire activity and its relation to changes in plant communities in the basin of lake Nizhnee Multinskoe (Altai Republic) in the late Holocene

High-resolution paleoenvironmental records of the bottom sediments from the lakes of the Altai make it possible to reconstruct the paleoecological situation in this unique region with several climatic zones and great variety of natural environments in detail. This article presents research into sediment column of Lake Nizhnee Multinskoe using palynological and macrocoal analyses. Occurrence of palaeofires for the last three thousand years and type of fire fuel (wood or grass) is reconstructed. Data on the type and distribution of coals in accordance with depth of the column from Lake Nizhnee Multinskoe was compared with palynological evidence and reconstructed dominant vegetation types. The results were also compared with macrocoal column from Lake Maloe Yarovoe. It has been established that periods of fire intensification for the sites of Altai Krai and Altai Republic had similar chronological boundaries (3-2 ka BP, about 1.5 ka BP, and last 200-500 years) and did not depend on climate changes. Forest fires prevailed in the area of Lake Nizhnee Multinskoe; plant communities showed connection with intensification of fires since the percentage of the taiga vegetation decreased during forest fires. The hypothesis on a connection between forest palaeofires and thunderstorms during the periods of seismic activity in the areas adjacent to the lake is proposed. The data on paleofires is compared with data on the areas and time of paleoearthquakes in the Altai Mountains.