A Holocene pollen record of boreal forest history from the Travaillant Lake area, Lower Mackenzie River Basin

• Published in: Canadian Journal of Botany
• Main Author: Ritchie, J. C.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1984
• Subjects: Plant Science; Northwest Territories; Mackenzie River; Canada; Travaillant Lake; Mackenzie river; Tundra
• Online Access: http://dx.doi.org/10.1139/b84-188; http://www.nrcresearchpress.com/doi/pdf/10.1139/b84-188

A 396-cm sediment sequence from SW Lake in the boreal woodland zone near Travaillant Lake, Northwest Territories, Canada, provides a Holocene record of pollen percentages and species interactions. Three local pollen assemblage zones are described: a Betula–Populus–Juniperus zone from 10 500 to 9000 years BP, a Picea–Betula zone from 9000 to 5100 years BP, and a Picea–Betula–Alnus zone from 5100 years BP to the present. The earliest vegetation recorded at this site is a mosaic of poplar groves, juniper and Shepherdia shrub, and fragmentary patches of tundra, replaced rapidly by spruce woodland at roughly 8500 years BP, dominated initially by Picea glauca. Picea mariana spread extensively between 8500 and 5000 years BP, probably as a function of increasing paludification. The present spruce-dominated vegetation was in place by 5000 years BP. Some changes in the pollen record can be explained by the Milankovitch early Holocene period of warmer summers followed by a cooling to modern conditions by 5000 years BP. Others require explanations in terms of edaphic factors or biological interactions among the main taxa.