DOCSLIB.ORG

Polar-FIT: Pliocene Landscapes and Arctic Remains—Frozen in Time

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Polar-FIT: Pliocene Landscapes and Arctic Remains—Frozen in Time Document generated on 09/30/2021 2:17 p.m. Geoscience Canada Journal of the Geological Association of Canada Journal de l’Association Géologique du Canada PoLAR-FIT Pliocene Landscapes and Arctic Remains—Frozen in Time J.C. Gosse, A.P. Ballantyne, J.D. Barker, A.Z. Csank, T.L. Fletcher, G.W. Grant, D.R. Greenwood, R.D.E. MacPhee and N. Rybczynski Volume 44, Number 1, 2017 Article abstract This short summary presents selected results of an ongoing investigation into URI: https://id.erudit.org/iderudit/1039606ar the feedbacks that contribute to amplified Arctic warming. The consequences of warming for Arctic biodiversity and landscape response to global warmth See table of contents are currently being interpreted. Arctic North American records of largescale landscape and paleoenvironmental change during the Pliocene are exquisitely preserved and locked in permafrost, providing an opportunity for Publisher(s) paleoenvironmental and faunal reconstruction with unprecedented quality and resolution. During a period of mean global temperatures only ~2.5°C above The Geological Association of Canada modern, the Pliocene molecular, isotopic, tree-ring, paleofaunal, and paleofloral records indicate that the High Arctic mean annual temperature was ISSN 11–19°C above modern values, pointing to a much shallower latitudinal temperature gradient than exists today. It appears that the intense Neogene 0315-0941 (print) warming caused thawing and weathering to liberate sediment and create a 1911-4850 (digital) continuous and thick (>2.5 km in places) clastic wedge, from at least Banks Island to Meighen Island, to form a coastal plain that provided a highway for Explore this journal camels and other mammals to migrate and evolve in the High Arctic. In this summary, we highlight the opportunities that exist for research on these and related topics with the PoLAR-FIT community. Cite this article Gosse, J., Ballantyne, A., Barker, J., Csank, A., Fletcher, T., Grant, G., Greenwood, D., MacPhee, R. & Rybczynski, N. (2017). PoLAR-FIT: Pliocene Landscapes and Arctic Remains—Frozen in Time. Geoscience Canada, 44(1), 47–54. All Rights Reserved © The Geological Association of Canada, 2017 This document is protected by copyright law. Use of the services of Érudit (including reproduction) is subject to its terms and conditions, which can be viewed online. https://apropos.erudit.org/en/users/policy-on-use/ This article is disseminated and preserved by Érudit. Érudit is a non-profit inter-university consortium of the Université de Montréal, Université Laval, and the Université du Québec à Montréal. Its mission is to promote and disseminate research. https://www.erudit.org/en/ GEOSCIENCE CANADA Volume 44 2017 47 ARTICLE SUMMARY This short summary presents selected results of an ongoing investigation into the feedbacks that contribute to amplified Arctic warming. The consequences of warming for Arctic bio- diversity and landscape response to global warmth are current- ly being interpreted. Arctic North American records of large- scale landscape and paleoenvironmental change during the Pliocene are exquisitely preserved and locked in permafrost, providing an opportunity for paleoenvironmental and faunal reconstruction with unprecedented quality and resolution. During a period of mean global temperatures only ~2.5°C above modern, the Pliocene molecular, isotopic, tree-ring, paleofaunal, and paleofloral records indicate that the High Arctic mean annual temperature was 11–19°C above modern values, pointing to a much shallower latitudinal temperature gradient than exists today. It appears that the intense Neogene PoLAR-FIT: Pliocene Landscapes and Arctic warming caused thawing and weathering to liberate sediment and create a continuous and thick (>2.5 km in places) clastic Remains—Frozen in Time wedge, from at least Banks Island to Meighen Island, to form J.C. Gosse1, A.P. Ballantyne2, J.D. Barker3,4, A.Z. Csank5, a coastal plain that provided a highway for camels and other T.L. Fletcher2, G.W. Grant4, D.R. Greenwood6, mammals to migrate and evolve in the High Arctic. In this R.D.E. MacPhee7 and N. Rybczynski8 summary, we highlight the opportunities that exist for research on these and related topics with the PoLAR-FIT community. 1Department of Earth Sciences, Dalhousie University 1459 Oxford St, Halifax, Nova Scotia, B3H 4R2, Canada RÉSUMÉ Email: [email protected] Ce bref résumé présente les résultats choisis d’une enquête en 2 cours sur les déclencheurs qui contribuent à l’amplification du College of Forestry and Conservation, University of Montana réchauffement de l’Arctique. Les conséquences du réchauffe- 32 Campus Drive, Missoula, Montana, 59801, U.S.A. ment sur la biodiversité arctique et de la réponse du paysage au 3School of Earth Sciences, The Ohio State University réchauffement climatique sont en cours d’être interprété. Des Marion, Ohio, 43302, U.S.A. dossiers nord-américains de paysage à grande échelle et le changement paléoenvironnementales durant le Pliocène sont 4 Byrd Polar and Climate Research Centre exceptionnellement préservés et scellées dans un état de con- Columbus, Ohio, 43210, U.S.A. gélation qui fournissant une occasion pour la reconstruction 5Department of Geography at the University of Nevada Reno paléoenvironnementale et faunistique avec une qualité et une 1664 N Virginia Street, Reno, Nevada, 89557, U.S.A. résolution sans précédent. Pendent une période de réchauffe- ment global seulement ~2,5°C au-dessus de moderne les 6Department of Biology, Brandon University dossiers, moléculaire, isotopique, annaux de croissance, paléo- 270 18th Street, Brandon, Manitoba, R7A 6A9, Canada faunistique et paléovégétation indiquent que l’Arctique a 7Department of Mammalogy, Division of Vertebrate Zoology connu une augmentation de la température annuelle moyenne American Museum of Natural History, de 11–19°C au-dessus de moderne, en montrant un inferieur Central Park West at 79th Street gradient de température latitudinal qu’aujourd’hui. Il semble New York, New York, 10024-5192, U.S.A. que le réchauffement intense pendent le Néogène a provoqué la décongélation et erosion pour libérer les sédiments et créer 8Canadian Museum of Nature une plaine côtière continuel et épaisse (> 2,5 km dans lieux) PO Box 3443, Station D, Ottawa, Ontario, K1P 6P4, Canada qui a fourni une route pour les chameaux et autres mam- Geoscience Canada, v. 44, https://doi.org/10.12789/geocanj.2017.44.116 pages 47–54 © 2017 GAC/AGC® 48 J.C. Gosse, A.P. Ballantyne, J.D. Barker, A.Z. Csank, T.L. Fletcher, G.W. Grant, D.R. Greenwood, R.D.E. MacPhee and N. Rybczynski Figure 1. Map of Arctic North America with geographic features described in the text. Previous ‘Pliocene Landscape and Arctic Remains—Frozen In Time’, (PoLAR-FIT) sites include: BP –Beaver Pond, BB –Ballast Brook, EL –Ekblaw Lake, FLB –Fyles Leaf Bed, GAP –‘The Gap’ on Meighen Island, RS –Remus Section, WCG –White Channel Gravel in the Klondike District, Yukon. The blue outline represents the modern onshore distribution of Beaufort Formation (Fyles et al. 1994). The original Beaufort For- mation has been interpreted by others to have formed a continuous Arctic Coastal Plain from Banks Island to Meighen Island, and possibly from the Mackenzie Delta to beyond Axel Heiberg Island. North Polar Projection DEM constructed with GEOMAPAPP v 3.6.4 using International Bathymetric Chart of the Arctic Ocean v 3, 30 arc- second resolution. mifères pour migrer et évoluer dans l’Haut-Arctique. Dans ce ably replicating low-latitude temperature proxies (Salzmann et résumé, nous soulignons les opportunités qui existent pour la al. 2013). The collective record suggests that there may be recherche sur ces sujets et les sujets connexes avec la commu- feedbacks that are not adequately represented by the models. nauté PoLAR-FIT. Temperature, humidity, CO2, and continentality may be con- trolled by factors such as different forest types and densities, INTRODUCTION sea-ice cover, the effects of forest fires, and the possibility that Today’s thawing of permanently frozen Pliocene clastic sedi- ocean circulation through the High Arctic was limited until the ments and organic layers in Arctic Canada and Alaska (Fig. 1) Beaufort Formation was incised and the Northwest Passages provides access to exquisitely preserved, sub-fossilized floral, were opened. Despite the discovery of well-preserved wood faunal, molecular, and isotopic records. These records docu- by explorers on Banks Island 150 years ago (Heer 1868), the ment amplification of temperature change in polar regions paleoenvironmental and paleoclimate research is still in its (e.g. Ballantyne et al. 2013) during periods of global warmth on infancy and the biochronostratigraphy is too imprecise to test the magnitude predicted for our next century (Masson-Del- synchroneity and reconcile the disparities among the sites. Fur- motte et al. 2013). The Pliocene sediments exposed onshore, thermore, accelerated processes such as retrogressive thaw including the Beaufort Formation, span a variety of deposi- slumping is rapidly removing or exposing previously tional environments (marine, lacustrine, paludal, alluvial, flu- entombed sedimentary, macrofossil, and biochemical records vial, and possibly glacial) over a wide temporal range (ca. 3.8 to before they can be examined within their stratigraphic context. 2.6 Ma; see later discussion of Geochronology), including To tackle these challenges, an international multidiscipli- varves and possible annual couplets of sand and leaf layers nary team has assembled with the shared objective of studying spanning a millennium. Until recently (e.g. Feng et al. 2017) these systems in an integrated way. The represented disciplines numerical models of Pliocene climate were unable to repro- include paleoclimatology, geomorphology, geochronology, duce the high paleo-temperatures in the High Arctic while reli- biogeochemistry, dendroclimatology, floral and faunal paleon- http://www.geosciencecanada.ca GEOSCIENCE CANADA Volume 44 2017 49 tology, evolutionary biology, and landscape ecology. Members Table 1. Founding PoLAR-FIT members. of the ‘Pliocene Landscape and Arctic Remains—Frozen In Time’, or PoLAR-FIT working group span from early-career to senior Ballantyne, A.
Load more

Recommended publications
  • Stratigraphic and Paleoenvironmental Reconstruction of a Mid-Pliocene Fossil Site in the High Arctic (Ellesmere Island, Nunavut)
    ARCTIC VOL. 69, NO. 2 (JUNE 2016) P. 185 – 204 http://dx.doi.org/10.14430/arctic4567 Stratigraphic and Paleoenvironmental Reconstruction of a Mid-Pliocene Fossil Site in the High Arctic (Ellesmere Island, Nunavut): Evidence of an Ancient Peatland with Beaver Activity William Travis Mitchell,1 Natalia Rybczynski,2,3 Claudia Schröder-Adams,1 Paul B. Hamilton,4 Robin Smith2 and Marianne Douglas5 (Received 12 June 2015; accepted in revised form 27 January 2016) ABSTRACT. Neogene terrestrial deposits of sand and gravel with preserved wood and peat accumulations occur in many areas of the High Arctic. The Pliocene-aged Beaver Pond fossil site (Ellesmere Island, NU) is one such site that differs from other sites in the great thickness of its peat layer and the presence of a rich vertebrate faunal assemblage, along with numerous beaver-cut sticks. Although the site has been the subject of intense paleontological investigations for over two decades, there has not been a reconstruction of its depositional history. In this study, measured sections within and surrounding the site established the stratigraphy and lateral continuity of the stratigraphic units. Grain size analysis, loss on ignition, and fossil diatom assemblages were examined to reconstruct paleoenvironmental changes in the sequence. The base of the section was interpreted as a floodplain system. Using modern peat accumulation rates, the maximum thickness (240 cm) of the overlying peat layer is estimated to represent 49 000 ± 12 000 years. From this evidence, we suggest that during the peat formation interval, beaver activity may have played a role in creating an open water environment.
    [Show full text]
  • Science Report
    P ROGRAMME DU P LATEAU LATEAU C ONTINENTAL ONTINENTAL P OLAR C ONTINENTAL S HELF P ROGRAM SCI E NCE P OLAIRE REPORT Logistical support for leading-edge Rapport Scientifique scientific research in the Canadian Arctic 2008 2009 2008-2009 2009 2008 2008-2009 dans l’Arctique canadien l’Arctique dans pointe de scientifique Soutien logistique à la recherche recherche la à logistique Soutien CIENTIFIQUE S Science Report T T R RAPPO ROGRAM P OLAIRE P ONTINENTAL C LATEAU P DU ROGRAMME P HELF S ONTINENTAL ONTINENTAL C OLAR P Polar Continental Shelf Program Science Report 2008/09: Logistical support for leading-edge scientific research in the Canadian Arctic Contact information Polar Continental Shelf Program Natural Resources Canada 615 Booth Street, Room 487 Ottawa ON K1A 0E9 Canada Tel.: 613-947-1650 E-mail: [email protected] Web site: pcsp.nrcan.gc.ca Cover photograph information A helicopter sits at a study site in the mountains of northern Ellesmere Island, Nunavut. (Credit: W. von Gosen) Cat. No. M78-1/1-2009 (Print) ISBN 978-1-100-51198-6 Cat. No. M78-1/1-2009E-PDF (On-line) ISBN 978-1-100-15115-1 © Her Majesty the Queen in Right of Canada, 2010 Recycled paper Table of contents 2 Minister’s message 4 The Polar Continental Shelf Program 5 Spotlight on a PCSP employee: George Benoit 6 The PCSP Resolute facility expansion: Improving support for Arctic science 6 PCSP Open House 2009 7 PCSP’s work with research organizations in Canada’s North 7 International Polar Year 8 The scientific legacy of Roy Koerner 9 PCSP-supported projects in the news 12 PCSP-supported field camps in the Canadian Arctic (2008) – map 14 PCSP-supported projects in 2008 13 Ecological integrity 20 Sustainable communities and culture 23 Climate change 30 Northern resources and development 33 Planetary science 36 National parks and weather stations A Twin Otter beside a field camp at Alexandra Fiord,Ellesmere Island, Nunavut J.
    [Show full text]
  • Using Tooth Enamel Microstructure to Identify Mammalian Fossils at an Eocene Arctic Forest
    PLOS ONE RESEARCH ARTICLE Using tooth enamel microstructure to identify mammalian fossils at an Eocene Arctic forest 1☯ 2☯ 3☯ Jaelyn J. EberleID *, Wighart von Koenigswald , David A. Eberth 1 University of Colorado Museum of Natural History and Department of Geological Sciences, University of Colorado, Boulder, Colorado, United States of America, 2 Institute of Geosciences (Section Palaeontology) at the Rheinische Friedrich-Wilhelms University, Bonn, Germany, 3 Royal Tyrrell Museum, Drumheller, Alberta, Canada a1111111111 ☯ These authors contributed equally to this work. [email protected] a1111111111 * a1111111111 a1111111111 a1111111111 Abstract Lower Eocene (Wasatchian-aged) sediments of the Margaret Formation on Ellesmere Island in Canada's High Arctic preserve evidence of a rainforest inhabited by alligators, tur- tles, and a diverse mammalian fauna. The mammalian fossils are fragmentary and often OPEN ACCESS poorly preserved. Here, we offer an alternative method for their identification. Among the Citation: Eberle JJ, von Koenigswald W, Eberth DA best preserved and extensive of the Eocene Arctic forests is the Strathcona Fiord Fossil For- (2020) Using tooth enamel microstructure to est, which contains permineralized in situ tree stumps protruding from a prominent coal identify mammalian fossils at an Eocene Arctic forest. PLoS ONE 15(9): e0239073. https://doi.org/ seam, but a paucity of vertebrate fossils. In 2010 and 2018, we recovered mammalian tooth 10.1371/journal.pone.0239073 fragments at the fossil forest, but they are so incomplete as to be undiagnostic by using their Editor: Adam Csank, University of Nevada, Reno, external morphology. We used a combination of light microscopy and SEM analysis to study UNITED STATES the enamel microstructure of two tooth fragments from the fossil forestÐNUFV2092B and Received: April 14, 2020 2092E.
    [Show full text]
  • Plants, Fungi, and Palaeoclimate of High Arctic Fossil Forests (Nunavut Palaeontology Permit No. 04-03P) James Basinger the Mode
    Plants, Fungi, and Palaeoclimate of High Arctic Fossil Forests (Nunavut Palaeontology Permit no. 04-03P) James Basinger The modern Arctic is defined by a cold climate, with brief cool summers, and long cold winters. There is also seasonal change in sunlight as well, so that summers experience continuous daylight, and the winters are continuously dark. The fossil record of plants in the High Arctic, however, has shown us that the climate was much warmer in the geological past. Our earlier work on fossil forests of Axel Heiberg and Ellesmere Island has revealed that towering forests of redwoods, cedars, oaks, walnuts, birch, pine and many other types of trees grew throughout the Far North about 50 million years ago. Warm temperatures and continuous daylight in the summers promoted rapid, lush growth, while the dark winters caused most trees to become dormant at the end of the summer, shedding their leaves and waiting for the return of the sun in the spring. Global temperatures declined after 40 million years ago, so that many of the warm-climate trees such as redwoods disappeared from the North. However, forests of spruce and larch, similar to forests now found around Great Slave Lake, existed throughout the High Arctic as recently as 3 million years ago. Fossils of trees and mosses, and fossil bones of many animals, have been discovered in the 3.5 million-year-old sediments near Strathcona Fiord on Ellesmere Island, these fossils indicate what life was like in the Arctic just before the beginning of the Ice Age. By knowing the kinds of plants that grew in the ancient arctic, we can say something about the kind of climate that existed there.
    [Show full text]
  • Neogene and Early Pleistocene Flora from Alaska, USA and Arctic/Subarctic Canada: New Data, Intercontinental Comparisons and Correlations
    Palaeontologia Electronica palaeo-electronica.org Neogene and early Pleistocene flora from Alaska, USA and Arctic/Subarctic Canada: New data, intercontinental comparisons and correlations T.L. Fletcher, A. Telka, N. Rybczynski, and J.V. Matthews, Jr. ABSTRACT A new correlation scheme primarily concerning macro- and meso-floral remains of bryophytes and vascular plants from 26 Neogene sites and over 50 florules in Alaska and northern Canada is presented. Flora are valuable for correlating Arctic Neogene sites, especially where absolute dating methods are not possible. These taxa clearly differentiate Neogene from Quaternary deposits in the North American Arctic. Recent age estimates provided using terrestrial cosmogenic nuclide (TCN) dating provide tie- points for these correlations and tend to confirm earlier dates achieved by relative and correlative methods. Our knowledge of North American Arctic/Subarctic palaeofloras and faunas is sufficiently detailed to allow inter-regional comparisons. This paper con- tains the first attempt to compare and contrast Neogene and early Pleistocene macro- and meso-floras from the entire circum-Arctic region. The subfossil and fossil floras are valuable for understanding the evolution of the boreal realm, from the qualitatively dif- ferent composition of the communities of the Neogene Arctic, to those of the more southerly modern boreal region. These differences may be due to the warm climate of the Neogene Arctic combined with the long dark of polar winter – a phenomenon with no modern analogue. The differences highlight the need for a comprehensive under- standing of species’ ecology to predict species ranges under near-future climate condi- tions analogous to our Neogene past. Many sites described here present rich opportunities for future cross-disciplinary study, including research related to the role of warm-climate intervals in patterning past and present Arctic ecosystems.
    [Show full text]
  • Quantitative Palynological Analyses Of
    University of Calgary PRISM: University of Calgary's Digital Repository Graduate Studies The Vault: Electronic Theses and Dissertations 2015-03-16 Quantitative palynological analyses of Albian-Cenomanian (Lower to Upper Cretaceous) strata in the Sverdrup Basin: Insights into paleoecology, paleoclimatology and palynostratigraphy Sulphur, Kyle Sulphur, K. (2015). Quantitative palynological analyses of Albian-Cenomanian (Lower to Upper Cretaceous) strata in the Sverdrup Basin: Insights into paleoecology, paleoclimatology and palynostratigraphy (Unpublished master's thesis). University of Calgary, Calgary, AB. doi:10.11575/PRISM/27507 http://hdl.handle.net/11023/2118 master thesis University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission. Downloaded from PRISM: https://prism.ucalgary.ca UNIVERSITY OF CALGARY Quantitative palynological analyses of Albian-Cenomanian (Lower to Upper Cretaceous) strata in the Sverdrup Basin: Insights into paleoecology, paleoclimatology and palynostratigraphy by Kyle Christopher Sulphur A THESIS SUBMITTED TO THE FACULTY OF GRADUATE STUDIES IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE GRADUATE PROGRAM IN GEOSCIENCE CALGARY, ALBERTA MARCH, 2015 © Kyle Christopher Sulphur 2015 Abstract Multivariate statistical analyses of terrestrial palynomorphs from Albian to Cenomanian (Lower to Upper Cretaceous), Sverdrup Basin strata reveal a landscape with wet lowlands inhabited by Pteridophytina and Bryophyta, with cooler, moist uplands inhabited by a variety of conifer plants. A humid and temperate climate prevailed at this time.
    [Show full text]
  • Polar Continental Shelf Program Science Report 2016: Logistical Support for Leading-Edge Scientific Research in Canada and Its Arctic
    PROGRAMME DU PLATEAU CONTINENTAL POLAIRE RAPPORT SCIENTIFIQUE 2016 POLAIRE RAPPORT CONTINENTAL PROGRAMME DU PLATEAU au Canada et dans l’Arctique dans et Canada au Soutien logistique à la recherche scientifique de pointe pointe de scientifique recherche la à logistique Soutien 2016 SCIENTIFIQUE RAPPORT Programme du plateau continental polaire continental plateau du Programme T 2016 Polar Continental Shelf Program SCIENCE REPOR SCIENCE REPORT 2016 Logistical support for leading-edge scientific research in Canada and its Arctic POLAR CONTINENTAL SHELF PROGRAM POLAR CONTINENTAL Polar Continental Shelf Program SCIENCE REPORT 2016 Logistical support for leading-edge scientific research in Canada and its Arctic Polar Continental Shelf Program Science Report 2016: Logistical support for leading-edge scientific research in Canada and its Arctic Contact information Polar Continental Shelf Program Natural Resources Canada 2464 Sheffield Road Ottawa ON K1B 4E5 Canada Tel.: 613-998-8145 Email: [email protected] Website: pcsp.nrcan.gc.ca Cover photograph: A meteorological, snow and permafrost data station in the Qarlikturvik valley, Bylot Island, Nunavut. The data from this station will be used to quantify the impact of willow growth on the permafrost thermal regime. Section header image: Preparing for departure on the Agassiz Ice Cap, Northern Ellesmere Island, after a successful ice core drilling mission. Photographers and map designers (alphabetically) Sean Arruda, Queen’s University: page 28 Max Friesen, University of Toronto: page
    [Show full text]
  • Radiocarbon Dates Iii W
    [RADIOCARBON, VOL. 6, 1964, P. 167-1811 GEOLOGICAL SURVEY OF CANADA RADIOCARBON DATES III W. DYCK and J. G. FYLES X Geological Survey of Canada, Ottawa, Canada INTRODUCTION All C14 measurements in this date list were made with the 2 L counter described in our first date list (GSC I). Ages were calculated on a C14 half life of 5570 ± 30 yr and 0.95 of the activity of the NBS oxalic-acid standard, and are quoted in years before 1950. In addition to the counting errors of sample, background, and standard, and the errors in the half life, all age errors starting with sample GSC-120 include an error term to account for the average variation of ± 1.5% in the C14 concentration during the past 1300 yr as measured by Willis, Tauber, and Munnich (1960) in sequoia tree rings. Similar results have been obtained by the author in work on an 1100-yr old Douglas fir from Vancouver Island, now nearing completion. The error term inserted to cover this variation makes little difference to the resultant error of older samples but gives a more realistic error for the young samples. For instance, in samples up to 1000 yr old, this correction generally accounts for about 50% of the age error, in a 10,000 yr sample about 30%, and in a 20,000 yr sample about 5%. No changes were made in the routine chemical pretreatment and CO2 preparation of organic samples. Sea shells with GSC numbers greater than 149 were treated with HCl to remove the outer 20% before the CO2 was collected for dating, rather than the outer 10% as in our earlier procedure.
    [Show full text]
  • Evolution of Woodcutting Behaviour in Early Pliocene Beaver Driven by Consumption of Woody Plants Tessa Plint1,2*, Fred J
    www.nature.com/scientificreports OPEN Evolution of woodcutting behaviour in Early Pliocene beaver driven by consumption of woody plants Tessa Plint1,2*, Fred J. Longstafe1, Ashley Ballantyne3, Alice Telka4,7 & Natalia Rybczynski5,6 Modern beavers (Castor) are prolifc ecosystem engineers and dramatically alter the landscape through tree harvesting and dam building. Little is known, however, about the evolutionary drivers of their woodcutting behaviour. Here we investigate if early woodcutting behaviour in Castoridae was driven by nutritional needs. We measured stable carbon and nitrogen isotopes (δ13C and δ15N) of coeval subfossil plants and beaver collagen (Dipoides sp.) from the Early Pliocene, High Arctic Beaver Pond fossil locality (Ellesmere Island), in order to reconstruct Dipoides sp. diet. Isotopic evidence indicates a diet of woody plants and freshwater macrophytes, supporting the hypothesis that this extinct semiaquatic beaver engaged in woodcutting behaviour for feeding purposes. In a phylogenetic context, the isotopic evidence implies that woodcutting and consumption of woody plants can be traced back to a small-bodied, semiaquatic Miocene castorid, suggesting that beavers have been consuming woody plants for over 20 million years. We propose that the behavioural complex (swimming, woodcutting, and consuming woody plants) preceded and facilitated the evolution of dam building. Dam building and food caching behaviours appear to be specializations for cold winter survival and may have evolved in response to late Neogene northern cooling. Beavers today are renowned for their woodcutting behaviour and construction abilities. Te extant genus Castor harvests trees and shrubs for sustenance (particularly during the winter1), but also for the purpose of lodge and dam building.
    [Show full text]
  • Looking Across a Line of Mummified Tree Stumps on Axel Heiberg Island
    Looking across a line of mummified tree stumps on Axel Heiberg Island. The yellow flowers are arctic poppies. Image © D. Greenwood, July 1991. Mummified tree stump of a dawn redwood (Metasequoia species, Cupressaceae) from the Middle Eocene Buchanan Lake Formation, on Axel Heiberg Island, in the Arctic Archipelago. These stumps are representative of extensive in situ stump fields or ”fossil forests‘ in life position from the Geodetic Hills, preserved in low-grade lignites in a thick fluvial plain sequence. The site is called —Napartulik“ (place of trees) by the Inuk, since the creation of Nunavut. Associated with these stumps are extensive mummified leaf-mats, preserving the forest-floor leaf litter of the original floodplain swamp-forests. The wood is preserved without chemical alteration (hence ”mummified‘), so perfectly that the original woodgrain and even bark is preserved, and the wood will burn. Analysis of the tree rings of these fossil trees has shown that the trees grew under very benign conditions, and formed part of polar forests that showed similar biological productivity to present-day coniferous temperate rainforests such as those on the west coast of Canada or southern Chile. Dawn redwoods are a deciduous conifer closely related to the coast redwood of the US west coast (Sequoia sempervirens) and the Chilean Alerce (Fitzroya). Metasequoia were first described as fossils (and are a common fossil from Paleogene rocks throughout North America), but were discovered as living trees in central China in 1944, and can today be found planted in the Toronto botanical gardens and elsewhere. Key references: Bartholomew, B., Boufford, D.E.
    [Show full text]
  • Early Pliocene Fish Remains from Arctic Canada Support a Pre-Pleistocene Dispersal of Percids (Teleostei: Perciformes)
    557 Early Pliocene fish remains from Arctic Canada support a pre-Pleistocene dispersal of percids (Teleostei: Perciformes) Alison M. Murray, Stephen L. Cumbaa, C. Richard Harington, Gerald R. Smith, and Natalia Rybczynski Abstract: Percid remains from Pliocene deposits on Ellesmere Island, Arctic Canada, are identified as a species of Sander, similar to the walleye and sauger of North America and the pike–perch of Europe and western Asia. They are named as a new species, Sander teneri. These remains are the most northerly percid elements found to date and suggest the palaeoen- vironment was significantly warmer in the Pliocene than it is currently. The fossil remains show the presence in North America of the family Percidae as well as the genus Sander prior to the Pleistocene, indicating a previously proposed Pleistocene immigration from Europe or Asia can be discounted. These fossils contradict an earlier hypothesis that percids, in particular Sander, crossed from Eurasia to North America in the Pleistocene; instead, the fossils show percids were al- ready in the area by the Pliocene. Re´sume´ : Des restes de percide´s provenant de de´poˆts plioce`nes de l’ıˆle Ellesmere, dans l’Arctique canadien, sont attribue´s a` une espe`ce de Sander semblable au dore´ jaune et au dore´ noir d’Ame´rique du Nord, et au sandre d’Europe et d’Asie oc- cidentale. Le nouveau nom d’espe`ce Sander teneri leur est attribue´. Ces restes constituent les e´le´ments de percide´s les plus nordiques trouve´sa` ce jour et portent a` croire que le pale´omilieu e´tait sensiblement plus chaud au Plioce`ne qu’il ne l’est actuellement.
    [Show full text]
  • August 16, 2011 Arctic Inventory Summary: Samples from the Prime
    August 16, 2011 Arctic Inventory Summary: Samples from the Prime Hill, Fossil Forest Hill, and Buchanan Lake Formation on Axel Heiberg Island are Middle Eocene in age. Samples from Stenkul Fjord on Ellesmere Island are Late Paleocene/Early Eocene in age. Isotope data are listed where available. Coal: We collected a single bulk sample from every coal layer present at the Axel Heiberg fossil forest site (2000) and Stenkul Fjord site (2001). Additionally, we performed fine scale sampling (every 2 cm through depth of coal) on coals along a lateral transect on Axel Heiberg Island. At Stenkul Fjord, we performed fine scale sampling on coals, which correspond with Kalkreuth’s section. Generally, there are 10s of grams of material per sub-sample. In the amber column, X = a minimal amount, XX = a mild amount, XXX = a large amount. Bulk coals were also collected from Bay Fiord and Strathcona Fiord on Banks Island in 2010. A few of these coals were indicated as being amber-rich. Litter: 80 of the 87 samples are from Axel Heiberg (Fossil Forest), 7 are from Ellesmere (Stenkul Fjord). These samples include Metasequoia, Glyptostrobus, and Betula leaves, assorted cones, possible fascicles rhizomes, fern rhizomes, and some bulk samples. Sample sizes range from grams to hundreds of grams. Most samples were collected in 2000. Wood: We have many pieces of whole wood (centimeter to decimeter scale) from every coal layer at the Axel Heiberg Site, varying in degree of preservation, from poor to excellent...(most of which have yielded at least some cellulose). Cellulose has been extracted for each ring for samples AXLR 2, AXLR-3, and AXLR-41.
    [Show full text]