Climate change and arctic ecosystems: 1. Vegetation changes north of 55 N between the Last Glacial Maximum, mid-Holocene, and present

• Main Authors: Nancy H. Bigelow, Linda B. Brubaker, Mary E. Edwards, Y P. Harrison, Torben R. Christensen Wolfgang Cramer
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2003
• Subjects: Arctic; Climate change; Keewatin; Tundra; Beringia; Siberia
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.373.3025; http://www.lter.uaf.edu/dev2009/pdf/911_bigelow_brubaker.pdf

[1] A unified scheme to assign pollen samples to vegetation types was used to reconstruct vegetation patterns north of 55°N at the last glacial maximum (LGM) and mid-Holocene (6000 years B.P.). The pollen data set assembled for this purpose represents a comprehensive compilation based on the work of many projects and research groups. Five tundra types (cushion forb tundra, graminoid and forb tundra, prostrate dwarf-shrub tundra, erect dwarf-shrub tundra, and low- and high-shrub tundra) were distinguished and mapped on the basis of modern pollen surface samples. The tundra-forest boundary and the distributions of boreal and temperate forest types today were realistically reconstructed. During the mid-Holocene the tundra-forest boundary was north of its present position in some regions, but the pattern of this shift was strongly asymmetrical around the pole, with the largest northward shift in central Siberia ( 200 km), little change in Beringia, and a southward shift in Keewatin and Labrador ( 200 km). Lowand high-shrub tundra extended farther north than today. At the LGM, forests were absent from high latitudes. Graminoid and forb tundra abutted on temperate steppe in northwestern Eurasia while prostrate dwarf-shrub, erect dwarf-shrub, and graminoid and