Holocene vegetation dynamics, river valley evolution and human settlement of the upper Kama valley, Ural region, Russia

We present a multi-proxy reconstruction of the Holocene environment in the northern upper Kama region of Russia (59 degrees 52'-60 degrees 28'N, 54 degrees 28'-56 degrees 28'E) based upon the pollen, plant macrofossil and radiocarbon records of the sedimentary successions from the floodplain deposits of the river Kama. Palaeochannel and geochronological investigations allowed us to identify seven stages of floodplain development, which were formed through increases or decreases in the water flow of this actively meandering river during the Holocene. These changes in river flow and channel activity in the upper Kama valley most probably influenced the choice of ancient people for places to settle. Pollen records from the palaeochannel sediments reflect three phases of regional vegetation changes in the study area: (1) predominance of sparse taiga forests with Pinus (pine), Betula (birch), Picea obovata (Siberian spruce) and Larix (larch) in the early and beginning of the middle Holocene (9,800-6,400 cal bp); (2) expansion of P. obovata and penetration and spread of the temperate-climate broad-leaved trees Ulmus, Quercus, Tilia and Alnus in the middle Holocene (6,400-4,200 cal bp), and (3) appearance and spread of Abies sibirica (Siberian fir) between 4,200 and 3,400 cal bp, and formation of closed canopy Abies-Picea forest without broad-leaved trees from ca. 2,700 cal bp. Plant macrofossil assemblages from these palaeochannel sediments indicate local vegetation of wetland or semi-aquatic plant communities in this area. Our results showed that the increase in Betula and decrease of the conifers Picea, Pinus and Abies with synchronous increases of ruderal plants such as Chenopodiaceae and Artemisia and also grassland taxa show woodland clearance by humans in the Chalcolithic ca. 4,000 cal bp and in the early Iron Age and Middle Ages between 2,700 and 1,300 cal bp.

Automated summary

This study presents a multi-proxy reconstruction of the Holocene environment in the northern upper Kama region of Russia, based on pollen, plant macrofossil, and radiocarbon records. The results indicate that changes in river flow and channel activity influenced the formation of floodplain deposits and possibly affected the settlement choices of ancient people.