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The Ecological implications of a Yakutian mammoth's last meal

Published online by Cambridge University Press:  20 January 2017

Bas van Geel*
Affiliation:
Institute for Biodiversity and Ecosystem Dynamics, Universiteit van Amsterdam, Kruislaan 318, 1098 SM Amsterdam, The Netherlands
André Aptroot
Affiliation:
Adviesbureau voor Bryologie en Lichenologie, Gerrit van der Veenstraat 107, 3762 XK Soest, The Netherlands
Claudia Baittinger
Affiliation:
NEDL — North European Dendro Lab, Copenhagen, and Environmental Archeology, National Museum of Denmark, Copenhagen, Denmark
Hilary H. Birks
Affiliation:
Department of Biology, University of Bergen, N-5007 Bergen, and Bjerknes Centre for Climate Research, N-5007 Bergen, Norway
Ian D. Bull
Affiliation:
Organic Geochemistry Unit, Bristol Biogeochemistry Research Centre, School of Chemistry, University of Bristol, Bristol, BS8 1TS, UK
Hugh B. Cross
Affiliation:
Nationaal Herbarium Nederland — Leiden University, Leiden, The Netherlands
Richard P. Evershed
Affiliation:
Organic Geochemistry Unit, Bristol Biogeochemistry Research Centre, School of Chemistry, University of Bristol, Bristol, BS8 1TS, UK
Barbara Gravendeel
Affiliation:
Institute for Biodiversity and Ecosystem Dynamics, Universiteit van Amsterdam, Kruislaan 318, 1098 SM Amsterdam, The Netherlands Nationaal Herbarium Nederland — Leiden University, Leiden, The Netherlands
Erwin J.O. Kompanje
Affiliation:
Erasmus MC University Medical Center Rotterdam, and Natural History Museum, Rotterdam, The Netherlands
Peter Kuperus
Affiliation:
Institute for Biodiversity and Ecosystem Dynamics, Universiteit van Amsterdam, Kruislaan 318, 1098 SM Amsterdam, The Netherlands
Dick Mol
Affiliation:
Natural History Museum, Rotterdam, The Netherlands
Klaas G.J. Nierop
Affiliation:
Institute for Biodiversity and Ecosystem Dynamics, Universiteit van Amsterdam, Kruislaan 318, 1098 SM Amsterdam, The Netherlands
Jan Peter Pals
Affiliation:
Amsterdam Archaeological Centre, Universiteit van Amsterdam, Amsterdam, The Netherlands
Alexei N. Tikhonov
Affiliation:
Zoological Institute, Russian Academy of Sciences, Saint Petersburg, Russia
Guido van Reenen
Affiliation:
Institute for Biodiversity and Ecosystem Dynamics, Universiteit van Amsterdam, Kruislaan 318, 1098 SM Amsterdam, The Netherlands
Peter H. van Tienderen
Affiliation:
Institute for Biodiversity and Ecosystem Dynamics, Universiteit van Amsterdam, Kruislaan 318, 1098 SM Amsterdam, The Netherlands
*
*Corrresponding author. Fax: +31 20 5257832.E-mail address:vanGeel@science.uva.nl (B. van Geel).

Abstract

Part of a large male woolly mammoth (Mammuthus primigenius) was preserved in permafrost in northern Yakutia. It was radiocarbon dated to ca. 18,50014C yr BP (ca. 22,500 cal yr BP). Dung from the lower intestine was subjected to a multiproxy array of microscopic, chemical, and molecular techniques to reconstruct the diet, the season of death, and the paleoenvironment. Pollen and plant macro-remains showed that grasses and sedges were the main food, with considerable amounts of dwarf willow twigs and a variety of herbs and mosses. Analyses of 110-bp fragments of the plastid rbcL gene amplified from DNA and of organic compounds supplemented the microscopic identifications. Fruit-bodies of dung-inhabiting Ascomycete fungi which develop after at least one week of exposure to air were found inside the intestine. Therefore the mammoth had eaten dung. It was probably mammoth dung as no bile acids were detected among the fecal biomarkers analysed. The plant assemblage and the presence of the first spring vessels of terminal tree-rings of dwarf willows indicated that the animal died in early spring. The mammoth lived in extensive cold treeless grassland vegetation interspersed with wetter, more productive meadows. The study demonstrated the paleoecological potential of several biochemical analytical techniques.

Type
Original Articles
Copyright
Elsevier Inc.

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References

Ager, T.A., (2003). Late Quaternary vegetation and climate history of the central Bering land bridge from St. Michael Island, western Alaska. Quaternary Research 60, 1932.CrossRefGoogle Scholar
Akashi, S., Saito, K., (1960). A branched saturated C15 acid (sarcinic acid) from sarcina phospholipids and a similar acid from several microbial lipids. Journal of Biochemistry 47, 222229.CrossRefGoogle Scholar
Andreev, A.A., Tarasov, P.E., Siegert, C., Ebel, T., Klimanov, V.A., Melles, M., Bobrov, A.A., Dereviagin, A.Yu., Lubinski, D.J., Hubberten, H.-W., (2003). Late Pleistocene and Holocene vegetation and climate on the northern Taymyr Peninsula, Arctic Russia. Boreas 32, 484505.CrossRefGoogle Scholar
Aptroot, A., van Geel, B., (2006). Fungi of the colon of the Yukagir Mammoth and from stratigraphically related permafrost samples. Review of Palaeobotany and Palynology 141, 225230.Google Scholar
Bethell, P.H., Goad, L.J., Evershed, R.P., Ottaway, J., (1994). The study of molecular markers of human activity: The use of coprostanol in the soil as an indicator of human faecal material. Journal of Archaeological Science 21, 619632.Google Scholar
Birks, H.H., (2001). Plant macrofossils. Smol, J.P., Birks, H.J.B., Last, W.M., Tracking environmental change using lake sediments. Volume 3, Terrestrial, algal and silicious indicators. Kluwer Academic Publishers, 4974.Google Scholar
Bull, I.D., van Bergen, P.F., Poulton, P.R., Evershed, R.P., (1998). Organic geochemical studies of soils from the Rothamsted Classical Experiments-II, Soils from the Hoosfield Spring Barley Experiment treated with different quantities of manure. Organic Geochemistry 28, 1126.Google Scholar
Bull, I.D., Simpson, I.A., van Bergen, P.F., Evershed, R.P., (1999a). Muck ‘n’ molecules: Organic geochemical methods for detecting ancient manuring. Antiquity 73, 8696.Google Scholar
Bull, I.D., Simpson, I.A., Dockrill, S.J., Evershed, R.P., (1999b). Organic geochemical evidence for the origin of ancient anthropogenic soil deposits at Tofts Ness, Sanday, Orkney. Organic Geochemistry 30, 535556.Google Scholar
Bull, I.D., Betancourt, P.P., Evershed, R.P., (2002a). An organic geochemical investigation of the practice of manuring at a Minoan site on Pseira Island, Crete. Geoarchaeology 16, 223242.Google Scholar
Bull, I.D., Lockheart, M.J., Elhmmali, M.M., Roberts, D.J., Evershed, R.P., (2002b). The origin of faeces by means of biomarker detection. Environment International 27, 647654.Google Scholar
Bull, I.D., Elhmmali, M.M., Roberts, D.J., Evershed, R.P., (2003). Using steroidal biomarkers to track the abandonement of a Roman wastewater course at the Agora (Athens, Greece). Archaeometry 45, 149161.Google Scholar
Challinor, J.M., (2001). Review: development and applications of thermally assisted hydrolysis and methylation reactions. Journal of Analytical and Applied Pyrolysis 61, 334.Google Scholar
Cooper, A., Poinar, H., (2001). Ancient DNA: do it right or not at all. Science 289, 1139.Google Scholar
Cwynar, L.C., (1982). A late-Quaternary vegetation history from Hanging Lake, Northern Yukon. Ecological Monographs 52, 124.Google Scholar
Cwynar, L., Ritchie, J.C., (1980). Arctic steppe-tundra: a Yukon perspective. Science 208, 13751377.Google Scholar
Davis, O.K., (1987). Spores of the dung fungus Sporormiella: increased abundance in historic sediments and before Pleistocene megafaunal extinction. Quaternary Research 28, 290294.Google Scholar
Davis, O.K., Shafer, D.S., (2006). Sporormiella fungal spores, a palynological means of detecting herbivore density. Palaeogeography, Palaeoclimatology, Palaeoecology 237, 4050.Google Scholar
Davis, O.K., Kolva, D.A., Mehringer, P.J., (1977). Pollen analysis of Wildcat Lake, Whitman County, Washington: the last 1000 years. Northwest Science 51, 1330.Google Scholar
Davis, O.K., Mead, J.I., Martin, P.S., Agenbroad, L.D., (1985). Riparian plants were a major component of the diet of mammoths of Southern Utah. Current Research in the Pleistocene 2, 8182.Google Scholar
De Leeuw, J.W., Versteegh, G.J.M., van Bergen, P.F., (2006). Biomacromolecules of algae and plants and their fossil analogues. Plant Ecology 182, 209233.Google Scholar
Drescher-Schneider, R., Jacquat, C., Schoch, W., (2007). Palaeobotanical investigations at the mammoth site of Niederweningen (Kanton Zürich), Switzerland. Quaternary International 164–165, 113129.Google Scholar
Elhmmali, M.M., Roberts, D.J., Evershed, R.P., (1997). Bile acids as a new class of sewage pollution indicator. Environmental Science and Technology 31, 36633668.Google Scholar
Elhmmali, M.M., Roberts, D.J., Evershed, R.P., (2000). Combined analysis of bile acids and sterols/stanols from riverine particulates to assess sewage discharges and other faecal sources. Environmental Science and Technology 34, 3946.CrossRefGoogle Scholar
Elias, S.A., Short, S.K., Nelson, C.H., Birks, H.H., (1996). Life and times of the Bering land bridge. Nature 382, 6063.CrossRefGoogle Scholar
Evershed, R.P., Bethell, P.H., Reynolds, P., Walsh, N.J., (1997). 5b-Stigmastanol and related 5b-stanols as biomarkers of manuring: analysis of modern experimental materials and assessment of the archaeological potential. Journal of Archaeological Science 24, 485495.CrossRefGoogle Scholar
Fægri, K., Iversen, J., Fægri, K., Kaland, P.E., Krzywinski, K., (1989). Textbook of Pollen Analysis. 4th edition Wiley and Sons, New York., .Google Scholar
Fajardo, G., Hornicke, H., (1989). Problems in estimating the extent of coprophagy in the rat. British Journal of Nutrition 62, 551561.Google Scholar
Fox-Dobbs, K., Leonard, J.A., Koch, P.L., in press. Pleistocene megafauna from eastern Beringia: paleoecological and paleoenvironmental interpretations of stable carbon and nitrogen isotope and radiocarbon records. Palaeogeography, Palaeoclimatology, Palaeoecology. doi:10.1016/j.palaeo.2007.12.011.Google Scholar
François, R.J., Eulderink, F., Bywaters, E.G., E.G.L., , (1995). Commented glossary for rheumatic spinal diseases, based on pathology. Annals of the Rheumatic Diseases 54, 615625.Google Scholar
Goetcheus, V.G., Birks, H.H., (2001). Full-glacial upland tundra vegetation preserved under tephra in the Beringia National Park, Seward Peninsula, Alaska. Quaternary Science Reviews 20, 135147.Google Scholar
Gorlova, R.N., (1982a). Large remains of plants from the stomach of the Shandrin Mammoth. Trudy Zoologicheskogo Instituta 3, 3435.Google Scholar
Gorlova, R.N., (1982b). The plant macroremains found in the enteron tract of the Yuribeyskiy mammoth. Sokolov, V.E., The Yuribeyskiy Mammoth. Nauka, Moscow., 3743.Google Scholar
Guthrie, R.D., (1990). Frozen Fauna of the Mammoth Steppe. The University of Chicago Press, Chicago., .Google Scholar
Guthrie, R.D., (2001). Origin and causes of the mammoth steppe: a story of cloud cover, woolly mammal tooth pits, buckles, and inside-out Beringia. Quaternary Science Reviews 20, 549574.Google Scholar
Guthrie, R.D., (2006). New carbon dates link climatic change with human colonization and Pleistocene extinctions. Nature 441, 207209.CrossRefGoogle ScholarPubMed
Hagey, L.R., Schteingart, C.D., Tonnu, H.T., Rossi, S.S., Hofmann, A.F., (1993). Unique bile alcohols (3,6,7,25,27-pentahydroxy cholestanes) and absence of bile-acids are a common feature of 3 ancient mammals. Hepatology 18, 4, A177-A177.CrossRefGoogle Scholar
Heal, O.W., Anderson, J.M., Swift, M.J., (1997). Plant litter quality and decomposition: an historic overview. Cadish, G., Giller, K.E., Driven by Nature; Plant Litter Quality and Decomposition. CAB International, Wallingford., 330.Google Scholar
Hofreiter, M., Poinar, H.N., Spaulding, W.G., Bauer, D., Martin, S., Possnert, G., Pääbo, S., (2000). A molecular analysis of ground sloth diet through the last glaciation. Molecular Ecology 9, 19751984.Google Scholar
Hofreiter, M., Betancourt, J.L., Sbriller, A.P., Markgraf, V., McDonald, H.G., (2003). Phylogeny, diet, and habitat of an extinct ground sloth from Cuchillo Cura, Neuquen Province, southwest Argentina. Quaternary Research 59, 364378.Google Scholar
Iacumin, P., Davanzo, S., Nikolaev, V., (2006). Spatial and temporal variations in the 13C/12C and 15N/14N ratios of mammoth hairs: palaeodiet and palaeoclimatic implications. Chemical Geology 231, 1625.Google Scholar
Kienast, F., (2007). Plant macrofossil records — Arctic Eurasia. Elias, S.A., Encyclopedia of Quaternary Science vol. 3. Elsevier, 24222434.Google Scholar
Kienast, F., Siegert, C., Derevyagin, A.Y., Mai, H.D., (2001). Climatic implications of late Quaternary plant macrofossil assemblages from the Taimyr Peninsula, Siberia. Global and Planetary Change 31, 265281.Google Scholar
Kienast, F., Schirrmeister, L., Siegert, C., Tarasov, P., (2005). Palaeobotanical evidence for warm summers in the East Siberian Arctic during the last cold stage. Quaternary Research 63, 283300.Google Scholar
Killops, S.D., Killops, J.K., (1993). An introduction to organic geochemistry. Longman Scientific and Technical. England, Harlow, Essex., .Google Scholar
Kolattukudy, P.E., (2001). Polyesters in higher plants. Scheper, T., Advances in Biochemical Engineering/Biotechnology vol. 71, Springer-Verlag, Heidelberg., 149.,Berlin.Google Scholar
Kompanje, E.J.O., (1999). Considerations on the comparative pathology of the vertebrae in Mysticeti and Odontoceti; evidence for the occurrence of discarthrosis, zygarthrosis, infectious spondylitis and spondyloarthritis. Zoölogische Mededeelingen Leiden 73, 99130.Google Scholar
Kompanje, E.J.O., Klaver, P.S.J., De Vries, G.T., (2000). Spondyloarthropathy and osteoarthrosis in three Indomalayan bears: Ursus ursinus Cuvier, 1823, Ursus thibetanus Raffles, 1821, and Ursus malayanus Shaw & Nodder, 1791 (Mammalia; Carnivora: Ursidae). Contributions to Zoology 69, 259269.Google Scholar
Krug, J.C., Benny, G.L., Keller, H.W., (2004). Coprophilous fungi. Mueller, G.M., Bills, G.F., Foster, M.S., Biodiversity of fungi. Elsevier, Amsterdam., 468499.Google Scholar
Kuch, M., Rohland, N., Betancourt, J.L., Latorre, C., Steppan, S., Poinar, H.N., (2002). Molecular analysis of an 11,700-year old rodent midden from the Atacama Desert, Chile. Molecular Ecology 11, 913924.Google Scholar
Kuroki, S., Schteingart, C.D., Hagey, L.R., Cohen, B.I., Mosbach, E.H., Rossi, S.S., Hofmann, A.F., Matoba, N., Une, M., Hoshita, T., Odell, D.K., (1988). Bile salts of the West Indian manatee, Trichechus manatus latirostris: novel bile alcohol sulfates and the absence of bile acids. Journal of Lipid Research 29, 509522.Google Scholar
Leggett, K., (2004). Coprophagy and unusual thermoregulatory behaviour in desert-dwelling elephants of north-western Namibia. Pachyderm 36, 113115.Google Scholar
Liu, T.S., Li, X.G., (1984). Mammoths in China. Klein, P.S., Klein, R.G., Quaternary Extinctions: A Prehistoric Revolution. University of Arizona Press, Tucson., 517527.Google Scholar
Mead, J.I., Agenbroad, L.D., Davis, O.K., Martin, P.S., (1986). Dung of Mammuthus in the arid southwest, North America. Quaternary Research 25, 121127.Google Scholar
Mol, D., Tikhonov, A.N., van der Plicht, J., Bolshiyanov, D.Yu., (2003). Discoveries of woolly mammoth, Mammuthus primigenius (Proboscidea: Elephantidae) and some other Pleistocene mammals on the Taimyr Peninsula. Russian Journal of Theriology 2, 7795.Google Scholar
Mol, D., Buigues, B., Tikhonov, A., Lazarev, P., van Geel, B., Fisher, D., Boeskorov, G., (2005). The Yukagir Mammoth — An Animal of the Cold Steppe (in Japanese). European Editions. Moscow.Google Scholar
Mol, D., Shoshani, J., Tikhonov, A., van Geel, B., Sano, S., Lazarev, P., Boeskorov, G., Agenbroad, L.D., (2006a). The Yukagir Mammoth: brief history, 14C dates, individual age, gender, size, physical and environmental conditions and storage. Scientific Annals, School of Geology, Aristotle University of Thessaloniki, Special Volume 98 299314.Google Scholar
Mol, D., Tikhonov, A., van der Plicht, J., Kahlke, R.D., Debruyne, R., van Geel, B., van Reenen, G., Pals, J.P., de Marliave, C., Reumer, J.W.F., (2006b). Results of the CERPOLEX/Mammuthus Expeditions on the Taimyr Peninsula, Arctic Siberia, Russian Federation. Quaternary International 142–143, 186202.Google Scholar
Mol, D., Shoshani, J., Tikhonov, A.N., Boeskorov, G.G., Lazarev, P.A., Agenbroad, L., Suzuki, N., Buigues, B., (2007). Anatomical-morphological features and individual age of the Yukagir mammoth. Boeskorov, G.G., Tikhonov, A.N., Suzuki, N., The Yukagir Mammoth. Saint-Petersburg University Publishing House, Saint-Petersburg., 97118.,(in Russian and in English).Google Scholar
Nierop, K.G.J., (2001). Temporal and vertical organic matter differentiation along a vegetation succession as revealed by pyrolysis and thermally assisted hydrolysis and methylation. Journal of Analytical and Applied Pyrolysis 61, 111132.CrossRefGoogle Scholar
Nierop, K.G.J., Verstraten, J.M., (2004). Rapid molecular assessment of the bioturbation extent in sandy soil horizons under pine using ester-bound lipids by on-line thermally assisted hydrolysis and methylation-gas chromatography/mass spectrometry. Rapid Communications in Mass Spectrometry 18, 10811088.Google Scholar
Nierop, K.G.J., Jansen, B., Hageman, J.A., Verstraten, J.M., (2006). The complementarity of extractable and ester-bound lipids in a soil profile under pine. Plant and Soil 286, 269285.Google Scholar
Olivier, R.C.D., (1982). Ecology and behavior of living elephants: bases for adaptations concerning the extinct woolly mammoths. Hopkins, D.M., Matthews, J.V., Schweger, C.E., Young, S.B., Paleoecology of Beringia. Academic Press, New York., 281290.Google Scholar
Reimer, P.J., Baillie, M.G.L., Bard, E., Bayliss, A., Beck, J.W., Bertrand, C.J.H., Blackwell, P.G., Buck, C.E., Burr, G.S., Cutler, K.B., Damon, P.E., Edwards, R.L., Fairbanks, R.G., Friedrich, M., Guilderson, T.P., Hogg, A.G., Hughen, K.A., Kromer, B., McCormac, F.G., Manning, S.W., Ramsey, C.B., Reimer, R.W., Remmele, S., Southon, J.R., Stuiver, M., Talamo, S., Taylor, F.W., van der Plicht, J., Weyhenmeyer, C.E., (2004). IntCal04 Terrestrial radiocarbon age calibration, 26 – 0 ka BP. Radiocarbon 46, 10291058.Google Scholar
Rollo, F., Ubaldi, M., Erminin, L., Marota, I., (2002). Otzi's last meals: DNA analysis of the intestinal content of the Neolithic glacier mummy from the Alps. Proceedings of the National Academy of Science 99, 1259412599.Google Scholar
Rothschild, B.M., Rothschild, C., (1994). No laughing matter: spondyloarthropathy and osteoarthritis in Hyaenidae. Journal of Zoo and Wildlife Medicine 25, 259263.Google Scholar
Rountrey, A.N., Fisher, D.C., Vartanyan, S., Fox, D.L., (2007). Carbon and nitrogen isotope analyses of a juvenile woolly mammoth tusk: evidence of weaning. Quaternary International 169–70, 166173.Google Scholar
Saito, K., (1960). Chromatographic studies on bacterial fatty acids. Journal of Biochemistry 47, 699709.Google Scholar
Schmidt, N.M., Baittinger, C., Forchhammer, M.C., (2006). Reconstructing century-long snow regimes using estimates of high Arctic Salix arctica radial growth. Arctic, Antarctic, and Alpine Research 38, 257262.Google Scholar
Sher, A.V., Kuzmina, S.A., Kuznetsova, T.V., Sulerzhitsky, L.D., (2005). New insights into the Weichselian environment and climate of the East Siberian Arctic, derived from fossil insects, plants, and mammals. Quaternary Science Reviews 24, 533569.Google Scholar
Shoshani, J., Mol, D., (2007). Estimated shoulder height and weight of the Yukagir mammoth (Mammuthus primigenius). Boeskorov, G.G., Boeskorov, A.N., Suzuki, N., The Yukagir Mammoth. Saint-Petersburg University Publishing House, Saint-Petersburg., 157166.,(in Russian and in English).Google Scholar
Solonevich, N.G., Tikhomirov, B.A., Ukraintseva, V.V., (1977). The preliminary results of the study of plant remnants from the enteron of Shandrin mammoth (Yakutia). Proceedings of the Zoological Institute Moscow 63, 277280.Google Scholar
Stuiver, M., Reimer, P.J., (1993). Extended 14C database and revised CALIB radiocarbon calibration program. Radiocarbon 35, 215230.Google Scholar
Sulerzhitsky, L.D., (1997). The features of radiocarbon chronology of mammoths in Siberia and northern Eastern Europe (as substratum for human colonization). Velichko, A.A., Soffer, O., Humans Settle the Planet Earth: Global Dispersal of Hominids. Institute of Geography. Russian Academy of Sciences, Moscow., 184202.,(in Russian).Google Scholar
Tütken, T., Furrer, H., Vennemann, T.W., (2007). Stable isotope compositions of mammoth teeth from Niederweningen, Switzerland: implications for the Late Pleistocene climate, environment, and diet. Quaternary International 164–65, 139150.Google Scholar
Ukraintseva, V.V., (1979). Vegetation of warm intervals of late Pleistocene and the extinction of some large herbivorous mammals. Botanicheskii Zhurnal 64, 318330.Google Scholar
Ukraintseva, V.A., (1993). Vegetation cover and environment of the Mammoth Epoch in Siberia. The Mammoth Site of Hot Springs South Dakota Inc., .Google Scholar
van Bergen, P.F., Bull, I.D., Poulton, P.R., Evershed, R.P., (1997). Organic geochemical studies of soils from the Rothamsted Classical Experiments — I. Total lipids, solvent insoluble residues and humic acids from Broadbalk Wilderness. Organic Geochemistry 26, 117135.Google Scholar
van Bergen, P.F., Nott, C.J., Bull, I.D., Poulton, P.R., Evershed, R.P., (1998). Organic geochemical studies of soils from the Rothamsted Classical Experiments — IV. Preliminary results from a study of the effect of soil pH on organic matter decay. Organic Geochemistry 29, 17791795.Google Scholar
van der Plicht, J., Beck, J.W., Bard, E., Baillie, M.G.L., Blackwell, P.G., Buck, C.E., Friedrich, M., Guilderson, T.P., Hughen, K.A., Kromer, B., McCormac, F.G., Bronk Ramsey, C., Reimer, P.J., Reimer, R.W., Remmele, S., Richards, D.A., Southon, J.R., Stuiver, M., Weyhenmeyer, C.E., (2004). NOTCAL04: comparison/calibration 14C records 26–50 cal kyr BP. Radiocarbon 46, 12251238.Google Scholar
van Geel, B., Aptroot, A., (2006). Fossil ascomycetes in Quaternary deposits. Nova Hedwigia 82, 313329.CrossRefGoogle Scholar
van Geel, B., Zazula, G.D., Schweger, C.E., (2007). Spores of coprophilous fungi from under the Dawson tephra (25,300 14C years BP), Yukon Territory, northwestern Canada. Palaeogeography, Palaeoclimatology, Palaeoecology 252, 481485.Google Scholar
Vasil'chuk, Y., Punning, J.M., Vasil'chuk, A., (1997). Radiocarbon ages of mammoths in Northern Eurasia: implications for population development and Late Quaternary environment. Radiocarbon 39, 118.Google Scholar
Walton, T.J., (1990). Waxes, cutin and suberin. Harwood, J.L., Bowyer, J.R., Methods in Plant Biochemistry 4. Academic Press, London., 105158.Google Scholar
Wampler, T.P., (1999). Review — Introduction to pyrolysis–capillary gas chromatography. Journal of Chromatography A 842, 207220.Google Scholar
Willerslev, E., Hansen, A.J., Binladen, J., Brand, T.B., Gilbert, T.P., Shapiro, B., Bunce, M., Wiuf, C., Gilichinsky, D.A., Cooper, A., (2003). Diverse plant and animal genetic records from Holocene and Pleistocene sediments. Science 300, 791795.Google Scholar
Yurtsev, B.A., (2001). The Pleistocene "Tundra-Steppe" and the productivity paradox: the landscape approach. Quaternary Science Reviews 20, 165174.Google Scholar
Zazula, G.D., Froese, D.G., Schweger, C.E., Mathewes, R.W., Beaudoin, A.B., Telkal, A.M., Harington, C.R., Westgate, J.A., (2003). Ice-age steppe vegetation in east Beringia. Nature 423, 603.Google Scholar
Zazula, G.D., Schweger, C.E., Beaudoin, A.B., McCourt, G.H., (2006a). Macrofossil and pollen evidence for full-glacial steppe within an ecological mosaic along the Bluefish River, eastern Beringia. Quaternary International 142–143, 219.Google Scholar
Zazula, G.D., Froese, D.G., Elias, S.A., Kuzmina, S., la Farge, C., Reyes, A.V., Sanborn, P.T., Schweger, C.E., Smith, C.A.S., Mathewes, R.W., (2006b). Vegetation buried under Dawson tephra (25,300 14C years BP) and locally diverse late Pleistocene paleoenvironments of Goldbottom Creek, Yukon, Canada. Palaeogeography, Palaeoclimatology, Palaeoecology 242, 253286.Google Scholar