Air moisture signals in a stable oxygen isotope chronology of dwarf shrubs from the central Tibetan Plateau
Wernicke J, Stark G, Wang L, Grießinger J, Bräuning A (2019)
Publication Type: Journal article
Publication year: 2019
Journal
Book Volume: 124
Pages Range: 53-64
Journal Issue: 1
DOI: 10.1093/aob/mcz030
Abstract
BACKGROUND AND AIMS: Annually resolved biological climate proxies beyond the altitudinal and latitudinal distribution limit of trees are rare. In such regions, several studies have demonstrated that annual growth rings of dwarf shrubs are suitable proxies for palaeoclimatic investigations. In High Asia, the pioneer work of Liang et al. (Liang E, Lu X, Ren P, Li X, Zhu L, Eckstein D, 2012. Annual increments of juniper dwarf shrubs above the tree line on the central Tibetan Plateau: a useful climatic proxy. Annals of Botany109: 721-728) confirmed the suitability of shrub growth-ring chronologies for palaeoclimatic research. This study presents the first sensitivity study of an annually resolved δ18O time series inferred from Wilson juniper (Juniperus pingii var. wilsonii) from the northern shoreline of lake Nam Co (Tibetan Plateau). METHODS: Based on five individual dwarf shrub discs, a statistically reliable δ18O chronology covering the period 1957-2009 was achieved (expressed population signal = 0.80). Spearman's correlation analysis between the δ18O chronology and climate variables from different sources was applied. In a first step, the suitability of various climate data was evaluated. KEY RESULTS: Examinations of climate-proxy relationships revealed significant negative correlations between the δ18O shrub chronology and summer season moisture variability of the previous and current year. In particular, relative humidity of the previous and current vegetation period significantly determined the proxy variability (ρ = -0.48, P < 0.01). Furthermore, the δ18O variability of the developed shrub chronology significantly coincided with a nearby tree-ring δ18O chronology of the same genus (r = 0.62, P < 0.01). CONCLUSIONS: The δ18O shrub chronology reliably recorded humidity variations in the Nam Co region. The chronology was significantly correlated with a nearby moisture-sensitive tree-ring δ18O chronology, indicating a common climate signal in the two chronologies. This climate signal was likely determined by moisture variations of the Asian summer monsoon. Local climate effects were superimposed on the supra-regional climate signature of the monsoon circulation. Opposing δ18O values between the two chronologies were interpreted as plant-physiological differences during isotopic fractionation processes.
Authors with CRIS profile
Jakob Wernicke
Institut für Geographie
Jussi Grießinger
Institut für Geographie
Achim Bräuning
Lehrstuhl für Geographie (Physische Geographie)
Involved external institutions
China (CN)How to cite
APA:
Wernicke, J., Stark, G., Wang, L., Grießinger, J., & Bräuning, A. (2019). Air moisture signals in a stable oxygen isotope chronology of dwarf shrubs from the central Tibetan Plateau. Annals of Botany, 124(1), 53-64. https://doi.org/10.1093/aob/mcz030
MLA:
Wernicke, Jakob, et al. "Air moisture signals in a stable oxygen isotope chronology of dwarf shrubs from the central Tibetan Plateau." Annals of Botany 124.1 (2019): 53-64.
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