Late- and postglacial vegetation and climate history of the central Kola Peninsula derived from a radiocarbon-dated pollen record of Lake Kamenistoe

A radiocarbon-dated sediment core collected from the small freshwater Lake Kamenistoe, in the central part of the Kola Peninsula, provides a pollen record of vegetation and climate history of this part of Fennoscandia and the European Arctic during the past ca. 13,000 years. In contrast to existing Scandinavian Ice Sheet reconstructions, the record shows that the study site was ice-free at 13 cal. kyr BP, thus allows to improve our knowledge on deglaciation dynamics in North Europe. The biome reconstruction results together with other pollen records from the wider region suggest that forest-tundra surrounded Kamenistoe at the end of the Bølling-Allerød interstadial and that the reconstructed presence of trees is not determined by far-distance pollen transport. The spread of pine in the study region started ca. 9.3 cal. kyr BP, and maximum pollen percentages during 8.2–4.2 cal. kyr BP mark the Holocene thermal optimum. Progressive climate cooling accompanied by increasing moisture levels from 6 cal. kyr BP is indicated by the spread of spruce (boreal evergreen conifer), reflecting the expansion of taiga forests. In contrast to some previous interpretations, we argue that the spread of pine in the Early Holocene and spruce in the Middle Holocene did not follow zonal expansions, but rather originated from scattered small populations withing the study region. Archaeological records from northern Fennoscandia suggest that postglacial human occupation on the Kola Peninsula began no later than 10,000 years ago. This northward expansion of hunter-gatherers was likely related to the continuous Early Holocene warming, which not only resulted in less harsh climatic conditions for human occupation, but may have also pushed reindeer populations to the study region. This game animal, which has been a major resource for humans, prefers July temperatures below 12–13 °C and thus may have migrated to cooler environments during the Early Holocene.