Postglacial paleoecology and inferred paleoclimate in the Engelmann spruce-subalpine fir forest of south-central British Columbia, Canada

摘要

Pollen, charcoal, and plant macrofossil analyses reveal five postglacial vegetation periods at Crater Lake, Crater Mountain, British Columbia. The first period, beginning ca. 11 400 ~(14)C yr BP was characterized by Artemisia steppe-tundra. At 9700 ~(14)C yr BP, Pinus parkland developed, and by 6700 ~(14)C yr BP was replaced by fire-successional Pinus-dominated Engelmann spruce and subalpine fir forest (ESSF). At 3800 ~(14)C yr BP, Picea became a more important element of the forest, and modern forest structure and composition developed by 1600 ~(14)C yr BP. Comparison of the fossil vegetation and fossil midge data derived from several ESSF sites in the southern interior reveals (1) similar late-Pleistocene vegetation and climate at all sites, (2) three distinct Holocene climatic stages: warm/dry, warm/moist, and cool/moist, (3) confirmation of the warm/moist period as a distinct climatic period, and (4) distinct differences in Holocene vegetation change among the sites. The driest and warmest site was most sensitive to climatic change, whereas cooler, moister sites were less sensitive. The present east-west climate gradient originated with postglacial warming at the beginning of the Holocene. Vegetation response to climate change and natural disturbance in these sites is strongly controlled by local site characteristics. These characteristics may have implications for forest, environment, and resource management.