A modern pollen–climate calibration set from central‐western Mongolia and its application to a late glacial–Holocene record

Abstract

Aim Fossil pollen spectra from lake sediments in central and western Mongolia have been used to interpret past climatic variations, but hitherto no suitable modern pollen-climate calibration set has been available to infer past climate changes quantitatively. We established such a modern pollen dataset and used it to develop a transfer function model that we applied to a fossil pollen record in order to investigate: (1) whether there was a significant moisture response to the Younger Dryas event in north-western Mongolia; and (2) whether the early Holocene was characterized by dry or wet climatic conditions. Location Central and western Mongolia.Methods We analysed pollen data from surface sediments from 90 lakes. A transfer function for mean annual precipitation (P ann ) was developed with weighted averaging partial least squares regression (WA-PLS) and applied to a fossil pollen record from Lake Bayan Nuur (49.98°N, 93.95°E, 932 m a.s.l.). Statistical approaches were used to investigate the modern pollen-climate relationships and assess model performance and reconstruction output.Results Redundancy analysis shows that the modern pollen spectra are characteristic of their respective vegetation types and local climate. Spatial autocorrelation and significance tests of environmental variables show that the WA-PLS model for P ann is the most valid function for our dataset, and possesses the lowest root mean squared error of prediction.Main conclusions Precipitation is the most important predictor of pollen and vegetation distributions in our study area. Our quantitative climate reconstruction indicates a dry Younger Dryas, a relatively dry early Holocene, a wet mid-Holocene and a dry late Holocene.

Quantitative woody cover reconstructions from eastern continental Asia of the last 22 kyr reveal strong regional peculiarities

“…Our pollen-based forest-cover reconstruction agrees with most reconstructions of the original pollen data: it does not show a largescale change in forest spatial extent over the last 22 kyr, but does indicate marked forest-cover changes on a regional to local scale, particularly in the forest-steppe transition areas, consistent with previous regional studies (north-central China, sub-region 2; Xiao et al, 2004;Sun et al, 2006;Liu et al, 2013; the eastern margin of the Tibetan Plateau, sub-region 4: Shen et al, 2005;Kramer et al, 2010aKramer et al, , 2010bHerzschuh et al, 2014; and north Mongolia and south Siberia, sub-region 6: Bezrukova et al, 2010;Tian et al, 2014). The model-simulated woody cover during the Holocene is of stable spatial extent for forest, which is generally consistent with the modern forest range and our pollen-based reconstruction.…”

Pollen‐based reconstructions of Late Holocene climate on the southern slopes of the central Tianshan Mountains, Xinjiang,NWChina

“…We tested the pollen‐based climate transfer function by comparison of the performance statistics with other quantitative models. As shown in Table S5, R 2 values for MAP and MAT were 0.5735 and 0.5952 in this study, higher than in most of the other models (Birks et al , ; Lotter et al , ; Herzschuh et al , ; Tian et al , ).…”

A pollen–climate calibration from western Patagonia for palaeoclimatic reconstructions

“…The importance of spatial autocorrelation in transfer functions evidenced by Telford and Birks () has been discussed by several authors (Telford and Birks, ; Guiot and de Vernal, ; Fréchette et al , ; Thompson et al , ). However, the problems of autocorrelation in evaluation models are rarely tested in transfer functions inferred from pollen data (Fréchette et al , ; Cao et al ., ; Tian et al , ), although these analyses are essential to obtain a robust transfer function.…”