Fables and foibles: a critical analysis of the Palaeoflora database and the Coexistence approach for palaeoclimate reconstruction

Abstract The ‘Coexistence Approach’ is a mutual climate range (MCR) technique combined with the nearest-living relative (NLR) concept. It has been widely used for palaeoclimate reconstructions based on Eurasian plant fossil assemblages; most of them palynofloras (studied using light microscopy). The results have been surprisingly uniform, typically converging to subtropical, per-humid or monsoonal conditions. Studies based on the Coexistence Approach have had a marked impact in literature, generating over 10,000 citations thus far. However, recent studies have pointed out inherent theoretical and practical problems entangled in the application of this widely used method. But so far little is known how results generated by the Coexistence Approach are affected by subjective errors, data errors, and violations of the basic assumptions. The majority of Coexistence Approach studies make use of the Palaeoflora database (the combination of which will be abbreviated to CA + PF). Testing results produced by CA + PF studies has been hindered by the general unavailability of the contents in the underlying Palaeoflora database; two exceptions are the mean-annual temperature tolerances and lists of assigned associations between fossils and nearest-living relatives. Using a recently published study on the Eocene of China, which provides the first and only insight into the data structure of the Palaeoflora database, we compare the theory and practice of Coexistence Approach using the Palaeoflora database (CA + PF). We show that CA + PF is riddled by association and climate data error. We reveal flaws in the application of the Coexistence Approach, which is often in stark contrast to the theory of the method. We show that CA + PF is highly vulnerable against numerous sources of errors, mainly because it lacks safeguards that could identify unreliable data. We demonstrate that the CA + PF produces coherent, pseudo-precise results even for artificially generated, random plant assemblages. Alternative MCR-NLR methods can surpass the most imminent deficits of the Coexistence Approach, and may be used as a stop-gap until more accurate bioclimatic and distribution data on potential Eurasian NLRs, and theoretically and statistically robust methods will become available. Finally, general guidelines are provided for the future application of methods using the mutual climatic range with nearest living relatives approach when reconstructing climate from plant fossil assemblages.

[1]  B. Dehgan,et al.  COMPARATIVE POLLEN MORPHOLOGY AND TAXONOMIC AFFINITIES IN CYCADALES , 1988 .

[2]  R. P. Wodehouse.  Tertiary Pollen-II The Oil Shales of the Eocene Green River Formation , 1933 .

[3]  R. S. Thompson,et al.  Atlas of relations between climatic parameters and distributions of important trees and shrubs in North America; additional conifers, hardwoods, and monocots , 2000 .

[4]  R. S. Thompson,et al.  Atlas of relations between climatic parameters and distributions of important trees and shrubs in North America— Modern data for climatic estimation from vegetation inventories , 2012 .

[5]  R. S. Thompson,et al.  Quantitative estimation of climatic parameters from vegetation data in North America by the mutual climatic range technique , 2012 .

[6]  J. L. Parra,et al.  Very high resolution interpolated climate surfaces for global land areas , 2005 .

[7]  S. Elias,et al.  Palaeoentomology of the Kap Kobenhavn Formation, a Plio-Pleistocene Sequence in Peary Land, North Greenland , 1997 .

[8]  Zhekun Zhou,et al.  Late Pliocene temperatures and their spatial variation at the southeastern border of the Qinghai-Tibet Plateau , 2015 .

[9]  G. Grimm,et al.  Evidence from "Köppen signatures" of fossil plant assemblages for effective heat transport of Gulf Stream to subarctic North Atlantic during Miocene cooling , 2013 .

[10]  N. Frederiksen.  Sporomorphs from the Jackson Group (upper Eocene) and adjacent strata of Mississippi and western Alabama , 1980 .

[11]  J. C. de Almeida,et al.  Concluding Remarks , 2015, Clinical practice and epidemiology in mental health : CP & EMH.

[12]  Robert S. Thompson,et al.  Atlas of relations between climatic parameters and distributions of important trees and shrubs in North America , 1999 .

[13]  Hans-Jürgen Beug,et al.  Leitfaden der Pollenbestimmung für Mitteleuropa und angrenzende Gebiete , 1961 .

[14]  A. Solomon,et al.  Further Scanning Electron Photomicrographs of Southwestern Pollen Grains , 1973 .

[15]  H. Nix,et al.  Quantitative palaeoclimatic estimates from pollen data using bioclimatic profiles of extant taxa , 1988 .

[16]  S. Manum.  Studies in the Tertiary flora of Spitsbergen, with notes on Tertiary floras of Ellesmere Island, Greenland, and Iceland : a palynological investigation , 1962 .

[17]  吴则焰,et al.  孑遗植物水松（Glyptostrobus pensilis）种群优势度增长规律研究 , 2008 .

[18]  G. Grimm,et al.  Fagaceae pollen from the early Cenozoic of West Greenland: revisiting Engler’s and Chaney’s Arcto-Tertiary hypotheses , 2014, Plant Systematics and Evolution.

[19]  C. Cannon,et al.  Phylogenetic Relationships and Taxonomic Status Of the Paleoendemic Fagaceae Of Western North America: Recognition Of A New Genus, Notholithocarpus , 2008 .

[20]  V. Hemleben,et al.  Evolutionary history and systematics of Acer section Acer – a case study of low-level phylogenetics , 2007, Plant Systematics and Evolution.

[21]  S. B. Archibald,et al.  Fossil biotas from the Okanagan Highlands, southern British Columbia and northeastern Washington State: climates and ecosystems across an Eocene landscape , 2005 .

[22]  A. Kershaw,et al.  Biogeographic, ecological and stratigraphic relationships of the Miocene brown coal floras, Latrobe Valley, Victoria, Australia , 1995 .

[23]  C. Earle.  The Gymnosperm database , 2015 .

[24]  R. Mittermeier,et al.  Hotspots: Earth's Biologically Richest and Most Endangered Terrestrial Ecoregions , 2000 .

[25]  G. Grimm,et al.  Significance of Pollen Characteristics for Infrageneric Classification and Phylogeny in Quercus (Fagaceae) , 2009, International Journal of Plant Sciences.

[26]  B. Tiffney.  Phylogeography, Fossils, and Northern Hemisphere Biogeography: The Role of Physiological Uniformitarianism1 , 2008 .

[27]  L. Sloan,et al.  Trends, Rhythms, and Aberrations in Global Climate 65 Ma to Present , 2001, Science.

[28]  W. Fletcher,et al.  Modern surface pollen assemblages from the Middle and High Atlas, Morocco: insights into pollen representation and transport , 2016 .

[29]  D. Nichols,et al.  ON ARECIPITES WODEHOUSE, MONOCOLPOPOLLENITES THOMSON & PFLUG, AND THE SPECIES “MONOCOLPOPOLLENITES TRANQUILLUS” , 1973 .

[30]  G. Grimm,et al.  Aponogeton pollen from the Cretaceous and Paleogene of North America and West Greenland: Implications for the origin and palaeobiogeography of the genus , 2014, Review of palaeobotany and palynology.

[31]  高志峰,et al.  OCCURRENCE OF EARLIEST CYCADS IN THE PERMIAN OF CHINA AND ITS BEARING ON THEIR EVOLUTION , 1989 .

[32]  S. Elias.  Mutual climatic range reconstructions of seasonal temperatures based on Late-Pleistocene fossil beetle assemblages in Eastern Beringia , 2001 .

[33]  T. Taylor,et al.  Paleobotany: The Biology and Evolution of Fossil Plants , 2008 .

[34]  B. A. Thomas,et al.  A review of fossil cycad megasporophylls, with new evidence of Crossozamia pomel and its associated leaves from the lower permian of Taiyuan, China , 1989 .

[35]  T. Denk,et al.  Evolutionary trends and ecological differentiation in early Cenozoic Fagaceae of western North America. , 2014, American journal of botany.

[36]  T. Denk,et al.  Late Cainozoic Floras of Iceland , 2011 .

[37]  B. Rudolf,et al.  World Map of the Köppen-Geiger climate classification updated , 2006 .

[38]  O. V. Bondarenko,et al.  The Cenozoic Cooling – continental signals from the Atlantic and Pacific side of Eurasia , 2015 .

[39]  L. Mautino,et al.  Palinología de la formación Chiquimil (Mioceno Superior) en Río Vallecito, provincia de Catamarca, Argentina. Parte 3. Polen , 2014 .

[40]  L. François,et al.  The Coexistence Approach—Theoretical background and practical considerations of using plant fossils for climate quantification , 2014 .

[41]  H. S. Rai,et al.  Recent Synchronous Radiation of a Living Fossil , 2011, Science.

[42]  Cheng-Sen Li,et al.  ‘CLAMP Online’: a new web-based palaeoclimate tool and its application to the terrestrial Paleogene and Neogene of North America , 2011 .

[43]  Thomas Denk,et al.  The oaks of western Eurasia: Traditional classifications and evidence from two nuclear markers , 2010 .

[44]  V. Hemleben,et al.  Patterns of molecular and morphological differentiation in Fagus (Fagaceae): phylogenetic implications. , 2005, American journal of botany.

[45]  E. Jäger,et al.  Vergleichende chorologie der zentraleuropaischen flora , 1993 .

[46]  R. S. Thompson,et al.  Atlas of Relations Between Climatic Parameters and Distributions of Important Trees and Shrubs in North America - Alaska Species and Ecoregions , 2006 .

[47]  M. Langer,et al.  The evolutionary history of Fagus in western Eurasia: Evidence from genes, morphology and the fossil record , 2002, Plant Systematics and Evolution.

[48]  S. Renner,et al.  Harvesting Betulaceae sequences from GenBank to generate a new chronogram for the family , 2013 .

[49]  C. Lewis,et al.  Phylogeny of the cycads based on multiple single-copy nuclear genes: congruence of concatenated parsimony, likelihood and species tree inference methods. , 2013, Annals of botany.

[50]  R. Schmid,et al.  Pollen Morphology and Plant Taxonomy. Angiosperms. (An Introduction to Palynology. I.) , 1987 .

[51]  G. Grimm,et al.  Reliability and resolution of the coexistence approach — A revalidation using modern-day data , 2012 .

[52]  T. Utescher,et al.  Eocene monsoon prevalence over China: A paleobotanical perspective , 2012 .

[53]  T. Denk,et al.  A combined light and scanning electron microscopy study , 2016 .

[54]  G. Grimm,et al.  From mesic to arid: Leaf epidermal features suggest preadaptation in Miocene dragon trees (Dracaena) , 2014 .

[55]  G. Grimm,et al.  Combined LM and SEM study of the middle Miocene (Sarmatian) palynoflora from the Lavanttal Basin, Austria: part IV. Magnoliophyta 2 – Fagales to Rosales , 2015 .

[56]  R. Cúneo.  Paleobotany: The Biology and Evolution of Fossil Plants , 2009 .

[57]  D. Mai,et al.  Blätter und Früchte von Engelhardia Lesch. ex Bl. (Juglandaceae) aus dem europäischen Tertiär , 1977 .

[58]  G. Grimm,et al.  Fallacies and fantasies: the theoretical underpinnings of the Coexistence Approach for palaeoclimate reconstruction , 2015 .

[59]  C. Filardi,et al.  PATTERNS OF MOLECULAR AND MORPHOLOGICAL VARIATION IN SOME SOLOMON ISLAND LAND BIRDS , 2007 .

[60]  P. S. Martin,et al.  Scanning Electron Photomicrographs of Southwestern Pollen Grains , 1969 .

[61]  W. H. Zagwijn.  Reconstruction of climate change during the Holocene in western and central Europe based on pollen records of indicator species , 1994 .

[62]  G. Grimm,et al.  The reticulate origin of modern plane trees (Platanus, Platanaceae): a nuclear marker puzzle. , 2010 .

[63]  G. Dupont‐Nivet,et al.  A late Eocene palynological record of climate change and Tibetan Plateau uplift (Xining Basin, China) , 2012 .

[64]  K. Browicz,et al.  Chorology of trees and shrubs in south-west Asia and adjacent regions , 1982 .

[65]  George E. Burrows,et al.  Juglandaceae A.Rich. ex Kunth , 2012 .

[66]  V. Bryant,et al.  Pollen of the southeastern United States: with emphasis on melissopalynology and entomopalynology. , 1995 .

[67]  S. Manchester.  The fossil history of the Juglandaceae , 1987 .

[68]  Christa‐charlotte Hofmann.  Pollen distribution in sub-Recent sedimentary environments of the Orinoco Delta (Venezuela) – an actuo-palaeobotanical study , 2002 .

[69]  D. Pocknall,et al.  Pollen morphology of Beauprea (Proteaceae): Modern and fossil , 1988 .

[70]  Tseng-chieng Huang.  Pollen flora of Taiwan , 1972 .

[71]  Zhekun Zhou,et al.  Quantitative reconstruction of the Late Miocene monsoon climates of southwest China: A case study of the Lincang flora from Yunnan Province , 2011 .

[72]  Z. Kvaček.  Do extant nearest relatives of thermophile European Cenozoic plant elements reliably reflect climatic signal , 2007 .

[73]  D. Soltis,et al.  Phylogeny of extant and fossil Juglandaceae inferred from the integration of molecular and morphological data sets. , 2007, Systematic biology.

[74]  M. Fortelius,et al.  Strong winter monsoon wind causes surface cooling over India and China in the Late Miocene , 2015 .

[75]  V. Mosbrugger,et al.  The coexistence approach — a method for quantitative reconstructions of Tertiary terrestrial palaeoclimate data using plant fossils , 1997 .

[76]  T. Denk,et al.  Review of the Cenozoic floras and vegetation of Greece , 2014 .

[77]  “Flora Europaea” , 1959, Nature.

[78]  A. Sluijs,et al.  A seasonality trigger for carbon injection at the Paleocene–Eocene Thermal Maximum , 2013 .

[79]  D. Greenwood,et al.  Late Eocene to middle Miocene (33 to 13 million years ago) vegetation and climate development on the North American Atlantic Coastal Plain (IODP Expedition 313, Site M0027) , 2014 .

[80]  G. Grimm,et al.  The biogeographic history of beech trees. , 2009 .

[81]  Charles H. Cannon,et al.  Systematics of Fagaceae: Phylogenetic Tests of Reproductive Trait Evolution , 2001, International Journal of Plant Sciences.

[82]  在原 重信,et al.  スギ(Cryptomeria japonica)黒心材の殺蟻成分 , 2004 .

[83]  T. Denk,et al.  E ff ective heat transport of Gulf Stream to subarctic North Atlantic during Miocene cooling : evidence from “ Köppe signatures ” of fo sil plant assemblages , 2013 .

[84]  Jingyun Fang,et al.  Atlas of Woody Plants in China , 2011 .

[85]  H. Hooghiemstra.  Atlas of pollen and spores of the Polish Neogene , 2005 .

[86]  A. Tryon,et al.  Spores of the Pteridophyta , 1991, Springer New York.

[87]  C. Ohlwein,et al.  Holocene climate variability in the Levant from the Dead Sea pollen record , 2012 .

[88]  T. McMahon,et al.  Updated world map of the Köppen-Geiger climate classification , 2007 .

[89]  V. Berry,et al.  Multiple nuclear genes stabilize the phylogenetic backbone of the genus Quercus , 2014 .

[90]  M. Dolezych,et al.  Taxonomy and taphonomy of coniferous woods and cuticulae dispersae in the Second Lusatian coal seam (Miocene) of the Senftenberg area , 2007 .

[91]  M. Kedves.  Palynological studies on Hungarian early Tertiary deposits , 1969 .

[92]  Hafida Chikhi,et al.  Pollen of wet evergreen forests of the Western Ghats, India , 1994 .

[93]  Yu-Fei Wang,et al.  Late Miocene vegetation and climate of the Lühe region in Yunnan, southwestern China , 2008 .