Holocene vegetation and climate change at Canyon Lake, Copper River basin, Alaska

Abstract

"The regional vegetation response to Holocene warming and the recession of glacial Lake Atria is recorded by environmental proxies in cores from Canyon Lake, near the northern limit of the Copper River Basin. Pollen, spores, plant macrofossils, and stable isotope analyses of C, N and H indicate that conditions in the northern margins stabilized fairly quickly following the recession of Lake Atria around 10740 cal yr BP. The development of a shallow lake ecosystem surrounded by Betula (birch) shrub-tundra was followed by the migration of Picea (spruce) and Alnus (alder) into the Copper River Basin around 9800 cal yr BP and the eventual development of the Picea-dominated boreal forest that persists to this day. The stable isotope record indicates that lake systems are more sensitive to neoglacial cooling, Medieval warming, and the Little Ice Age than the surrounding boreal forest during the middle to late Holocene. The magnitude and severity of these events may have been limited in the Copper River Basin, but climate and vegetation change may have had significant effects on the available resources to the human populations of the region"--Leaf iii