A multi-proxy reconstruction of peatland development and regional vegetation changes in subarctic NE Fennoscandia (the Republic of Karelia, Russia) during the Holocene

摘要

A better understanding of past long-term environmental changes in the subarctic region is crucial for mitigation of the possible negative effects of climate warming in this vulnerable region. This study provides a new multi-proxy reconstruction of regional vegetation changes and peatland development for north-eastern Fennoscandia (Russia) during most of the Holocene. To that purpose, we performed plant macrofossil, pollen, testate amoebae, peat humification, loss on ignition and radiocarbon analyses of the peat deposits from a mire around Vodoprovodnoe Lake (the Kindo Peninsula, the Republic of Karelia). Our data indicate that the peat deposits started accumulating before 9147 ± 182 cal. yr. BP. The vegetation cover in the area was mainly typical for the northern taiga zone, except for the period ~7800–5600 cal. yr. BP, when it generally resembled the middle taiga zone. The vegetation cover and peatland were greatly affected by reoccurring fires, which can be partly related to human activity. These events were associated with an increased proportion of birch in the vegetation cover (as a pioneer species) and/or water level decreases. By 600 cal. yr. BP, the peatland and the surrounding vegetation reached its current state and only minor changes had been recorded since that time. Overall, our results suggest a considerable and unexpected role of fires in the postglacial dynamics of subarctic peatlands.