Vegetation responses to interglacial warming in the Arctic: examples from Lake El'gygytgyn, Far East Russian Arctic

A V Lozhkin,P M Anderson

doi:10.5194/cp-9-1211-2013

Abstract

Abstract. Preliminary analyses of Lake El'gygytgyn sediment indicate a wide range of ecosystem responses to warmer than present climates. While palynological work describing all interglacial vegetation is ongoing, sufficient data exist to compare recent warm events (the postglacial thermal maximum, PGTM, and marine isotope stage, MIS5) with "super" interglaciations (MIS11, MIS31). Palynological assemblages associated with these climatic optima suggest two types of vegetation responses: one dominated by deciduous taxa (PGTM, MIS5) and the second by evergreen conifers (MIS11, MIS31). MIS11 forests show a similarity to modern Picea–Larix–Betula–Alnus forests of Siberia. While dark coniferous forest also characterizes MIS31, the pollen taxa show an affinity to the boreal forest of the lower Amur valley (southern Russian Far East). Despite vegetation differences during these thermal maxima, all glacial–interglacial transitions are alike, being dominated by deciduous woody taxa. Initially Betula shrub tundra established and was replaced by tundra with tree-sized shrubs (PGTM), Betula woodland (MIS5), or Betula–Larix (MIS11, MIS31) forest. The consistent occurrence of deciduous forest and/or high shrub tundra before the incidence of maximum warmth underscores the importance of this biome for modeling efforts. The El'gygytgyn data also suggest a possible elimination or massive reduction of Arctic plant communities under extreme warm-earth scenarios.

Highlights

Earth System SciencesMarine and ice cores contain vital data that document fluctuations in past climate and provide insight into the possible causes of the observed paleoclimatic variability
The vegetation in the first type of thermal optimum is dominated by deciduous tree and shrub species and corresponds to the two most recent warming events (PGTM, MIS5.5): the second type, or “super” interglaciation (MIS11.3, MIS31), indicates climax vegetation dominated by evergreen conifers, Picea
These exceptional climatic events experienced warmer summers (+4.5 ◦C) and greater annual precipitation (∼ 300 mm) as compared to the postglacial thermal maximum (PGTM) and MIS5.5 (Melles et al, 2012), which themselves are characterized by summers that are warmer and wetter than present

Summary

Introduction

Marine and ice cores contain vital data that document fluctuations in past climate and provide insight into the possible causes of the observed paleoclimatic variability. Such records cannot prOovicdeeianfnormSactiioennonctehe responses of biotic systems to those changes. MIS31 have been described as “super interglaciations” with maximum summer temperatures ∼ 4 to 5 ◦C warmer than either MIS5.5 or the postglacial thermal maximum (PGTM; Melles et al, 2012) These warmer-than-present intervals are of particular interest for understanding possible responses and feedbacks related to increasing global temperatures (e.g., Harrison et al, 1995; Kaplan et al, 2003). Analysis continues on Lake E, sufficient palynological data are available to compare the vegetation responses during the “super interglaciations” and the more moderate warming represented in MIS5.5 and the PGTM

Methods

Modern setting

Interglacial vegetation of Lake E and the Chukchi Uplands

MIS 31

Findings

Discussion and conclusions