A new method based on surface- sample pollen data for reconstructing palaeovegetation patterns.
Author(s)
Cruz-Silva, Esmeralda
Harrison, Sandy P
Marinova-Wolff, Elena
Prentice, Iain Colin
Type
Journal Article
Abstract
Aim: Amongst the various techniques available to reconstruct past vegetation at regional to continental scales, biomisation has been the most widely used because it does not require an extensive modern pollen data set. However, it has well well-known limitations including its dependence on expert judgement for the assignment of pollen taxa to plant functional types (PFTs) and PFTs to biomes. Here we present a new method that combines the strengths of biomisation with those of the alternative dissimilarity-based techniques. This new technique quantifies the likelihood that a sample belongs to a given biome, and allows discrimination of non-analogue vegetation types. Location: The Eastern Mediterranean-Black Sea Caspian Corridor (EMBSeCBIO) region, 28°-49°N, 20°- 62°E. Methods: Modern pollen samples assigned to biomes based on potential natural vegetation data, are used to characterize biomes according to the within-biome means and standard deviations of the abundances of each taxon. These are used to calculate a dissimilarity index between any given pollen sample and every biome, and thus assign a pollen sample to the most likely biome. We also calculate a threshold value for each biome which identifies samples that fall outside the acceptable range of likelihoods for biome assignment and hence can be used to distinguish non-analogue vegetation. We have applied the new technique to the EMBSeCBIO region to compare the performance of the new method with existing reconstructions. Results: The technique captured changes in the importance of individual taxa along environmental gradients. The balanced accuracy obtained for the EMBSeCBIO region using the new method was better than that obtained using biomisation (77% versus 65%). When the method was applied to high resolution fossil records, 70% of the evaluated entities showed more temporally stable biome assignments than obtained with the biomisation method. The technique also identifies likely non analogue assemblages in a synthetic modern data set and in fossil records. Main conclusions: The new method yields more accurate and stable reconstructions of vegetation than the biomisation method. It requires an extensive modern pollen dataset, but is conceptually simple, and avoids subjective choices about taxon allocations to PFTs and PFTs to biomes.
Date Issued
2022-07
Date Acceptance
2022-04-30
Citation
Journal of Biogeography, 2022, 49 (7), pp.1381-1396
ISSN
0305-0270
Publisher
Wiley
Start Page
1381
End Page
1396
Journal / Book Title
Journal of Biogeography
Volume
49
Issue
7
Copyright Statement
© 2022 The Authors. Journal of Biogeography published by John Wiley & Sons Ltd.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
License URL
Sponsor
Commission of the European Communities
Identifier
https://onlinelibrary.wiley.com/doi/10.1111/jbi.14448
Grant Number
787203
Subjects
Science & Technology
Life Sciences & Biomedicine
Physical Sciences
Ecology
Geography, Physical
Environmental Sciences & Ecology
Physical Geography
biomes
biomisation
Eastern Mediterranean
EMBSeCBIO
palaeovegetation
pollen data
potential natural vegetation
vegetation change
vegetation reconstruction
PLANT MACROFOSSIL DATA
BIOME RECONSTRUCTIONS
0 C-14
QUANTITATIVE RECONSTRUCTION
GLACIAL-MAXIMUM
MODERN ANALOGS
CLIMATE-CHANGE
SOURCE AREA
LAND-USE
VEGETATION
Ecology
04 Earth Sciences
05 Environmental Sciences
06 Biological Sciences
Publication Status
Published
Date Publish Online
2022-06-15