Paleoenvironmental Analysis of Insects and Extralimital Populus from an Early Holocene Site on the Arctic Slope of Alaska, U.S.A.
Nelson RE and Carter LD. 1987. Paleoenvironmental Analysis of Insects and Extralimital Populus from an Early Holocene Site on the Arctic Slope of Alaska, U.S.A.. Arctic and Alpine Research. 19(3):230-241
Analysis of pollen and plant and insect macrofossils from 9400-yr-old fluvial terrace deposits along the Ikpikpuk River on the Arctic Slope of Alaska permit reconstruction of the diversity of habitats present at that time, as well as an assessment of surface moisture conditions and summer temperatures relative to those of today. Consideration of the modern ecological requirements for the total fossil flora and fauna shows that the variety of habitats was similar to the total variety seen today. However, the beetle fauna is dominated by species indicative of dry, open grasslands, suggesting that dry, well-drained habitats were more widespread than now. Warmer summer temperatures are indicated by extralimital taxa including Populus balsamifera and seven beetle species that reach their present northern limits in the boreal forest zone of north-central Alaska and adjacent Canada. Consideration of the modern climatic tolerances of the beetle taxa suggests that early Holocene mean July temperatures at the fossil site were probably about 2 to 3°C warmer than today, or 14 to 15°C. Geological evidence indicates net precipitation was comparable to, or possibly greater than, that of today. Elevated summer temperatures may have contributed to dry surface conditions by lowering the permafrost table and thereby facilitating drainage.
- Type
- Journal Article
- Authors
- Nelson, Robert; Carter, L
- Units
- BELA , CAKR , GAAR , KOVA , NOAT
- Keywords
- Arctic, Holocene, Insects, Paleoecology, Paleontology, Populus, Vegetation