LATE QUATERNARY VEGETATION DYNAMICS OF THE QUEEN CHARLOlTE ISLANDS, NORTHERN VANCOUVER ISLAND, AND THE CONTINENTAL SHELF OF BRITISH COLUMBIA, CANADA Terri Lacourse B.A. (Geography), University of Ottawa, 1996 M.A. (Geography), University of Ottawa, 1998 THESIS SUBMllTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in the Department of Biological Sciences @ Terri Lacourse 2004 SIMON FRASER UNIVERSITY July 2004 All rights reserved. This work may not be reproduced in whole or in part, by photocopy or other means, without permission of the author. Name: Terri Lacourse Degree: Doctor of Philosophy Title of Thesis: Late Quaternary Vegetation Dynamics of the Queen Charlotte Islands, Northern Vancouver Island, and the Continental Shelf of British Columbia, Canada Examining Committee: Chair: Dr. A.P. Farrell, Professor Dr. R.W. Mathewes, Professor, Senior Supervisor Department of Biological Sciences, S.F.U. Dr. 3.3. Claque, Professor Department of Earth Sciences, S.F.U. Dr. I.R. Walker, Adjunct Professor Department of Biological Sciences, S.F.U. Dr. E. Elle, Assistant Professor Department of Biological Sciences, S.F.U. Public Examiner Dr. D.M. Peteet, Adjunct Senior Research Scientist Lamont Doherty Earth Observatory, Columbia University & NASAIGoddard Institute for Space Studies External Examiner Date Approved: Partial Copyright Licence The author, whose copyright is declared on the title page of this work, has granted to Simon Fraser University the right to lend this thesis, project or extended essay to users of the Simon Fraser University Library, and to make partial or single copies only for such users or in response to a request from the library of any other university, or other educational institution, on its own behalf or for one of its users. The author has further agreed that permission for multiple copying of this work for scholarly purposes may be granted by either the author or the Dean of Graduate Studies. It is understood that copying or publication of this work for financial gain shall not be allowed without the author's written permission. The original Partial Copyright Licence attesting to these terms, and signed by this author, may be found in the original bound copy of this work, retained in the Simon Fraser University Archive. Bennett Library Simon Fraser University Burnaby, BC, Canada Paleoecological analyses and radiocarbon dating of late-Quaternary sediments from the Queen Charlotte Islands (QCI), northern Vancouver Island, and the continental shelf along the coast of British Columbia reveal substantial changes in vegetation and climate over the last 14,000 14c yr (17,000 cal yr). Extensive portions of the shelf were subaerially exposed at the end of the last glaciation due to lowering of relative sea level by as much as 150 m. AMS radiocarbon ages indicate that the shelf in Hecate Strait was exposed between at least 14,330 and 12,860 14c yr BP. Cyperaceae were locally abundant on the exposed shelf, and fossil Pediastrum algae indicate the presence of freshwater. Interpretation of pollen from late-glacial lake sediments in the southern QCI suggest a succession from herb tundra dominated by Cyperaceae to dwarf shrub tundra including Salix and Empetrum before the development of Pinus contorta woodland. Fossil stomata suggest that Pinus contorta grew locally by 13,040 + 305 14C yr BPI and an in situ Pinus stump and associated plant macrofossils demonstrate that forests grew on the adjacent shelf 12,200 14cyr BP. Submerged lake sediments in Logan Inlet record the transition from Pinus contorta woodland to Picea forests about 11,200 14cyr BP. Northern Vancouver Island also supported Pinus contorta woodland during the late-glacial period. Mixed coniferous forests dominated by Pinus contorta with Alnus and pteridophytes occupied the shelf north of Vancouver Island 10,500 14c yr BP. Warming in the early Holocene allowed the northward extension of Pseudoiwga menziesiii, although Picea, Tsuga heterophylla, and Alnus rubra dominated regional forests. By 7500 14c yr BPI shade-tolerant Tsuga heterophylla was the dominant forest tree. A cooler and wetter climate in the late Holocene facilitated development of temperate coniferous rainforest. This research, in combination with earlier studies, demonstrates that portions of the continental shelf were ice-free and vegetated between 14,300 and 9,500 14c yr BP; moderate climatic conditions supported diverse and productive vegetation while adjacent mainland areas remained glaciated. Stratigraphic sequences spanning the last glaciation are still required to confirm the existence of continuous late Pleistocene glacial refugia in the QCI region. - To Matt The reference list is the best record of my intellectual indebtedness. There are, however, many people that deserve thanks in helping with this thesis. Iwould like to extend my sincerest thanks to my Senior Supervisor, Dr. Rolf W. Mathewes, for his support in all aspects of this research. Iwould also like to thank the other members of my supervisory committee, Drs. Ian R. Walker and John J. Clague, for their guidance and support through the years. Thanks are also due to Dr. Elizabeth Elle for serving as Public Examiner and to Dr. Dorothy M. Peteet for serving as External Examiner. The time and thought Drs. Elle and Peteet devoted to my thesis improved it greatly and is much appreciated. Many others have been instrumental in the completion of this research. Thanks to Daryl Fedje (Parks Canada) for providing previously unpublished radiocarbon ages and access to the Juan Perez Sound and West Side Pond sediment samples, and to Vaugh Barrie, Kim Conway and John Luternauer (Geological Survey of Canada) for providing access to various marine sediment cores. I also thank Dr. John Birks (University of Bergen) for help with multivariate statistical analysis, Dr. K.D. Bennett (Uppsala Universitet) for a copy of psimpoll, P. Lee for processing Misty Lake sediments, R. Foottit and E. Maw (Agriculture Canada) for the aphid identification, D. Chu and D. Morrison (Forestry Canada) for the Basidiomycete identification, and K. Conway (Geological Survey of Canada) for photographs used in Figure 3.2. Constructive reviews were provided by Drs. T. Ager, L.C. Cwynar, E. Elle, M.G. Pellatt, I.R. Walker, and D.M. Peteet, and several anonymous reviewers. Financial support was provided by the Natural Sciences and Engineering Research Council of Canada through Research Grants to Rolf W. Mathewes, and by a Geological Society of American Research Grant to me. I was supported by a Post- Graduate Scholarship from the Natural Sciences and Engineering Research Council of Canada, and by Graduate Fellowships and the President's Ph.D. Research Stipend from Simon Fraser University. Iwould also like to thank Dr. Jon Driver, Dean of Graduate Studies, for serving as Public Examiner at my Ph.D. candidacy exam and for organizing an informative special topics course on human migration into the Americas. Ialso thank Dr. Driver and his assistant, Debbie Sandher, for providing me with a quiet study room in the SFU library during the final stages of this research. Thanks to Dr. Barbara Wohlfarth for hosting me at Lund Universitet in Sweden. Thanks to Drs. Konrad Gajewski, Les Cwynar, and Cyril Thong for their support and mentorship. Thanks to Marlene Nguyen, Sylvia Foran, Barbara Sherman, Faith Rapchuk, Brian Medford, Dr. Dave Carmean, Derek Steel, Fiona Burrows, and other staff in the Department of Biological Sciences for help with administrative, equipment, and computer matters. Thanks to Matt, Keith, Georgeanna, Cory, and especially Connie for moral support, encouragement, and distraction. I thank my parents for all of the support and encouragement they have extended throughout my education. Finally, I would like to thank R. Will Stein for his help, support, and companionship. Will familiarized himself with a research area far from his own area of expertise and provided constructive feedback at all stages. He helped both with details and the big picture, reviewed manuscripts, and aided with the production of the thesis. I cannot express how grateful Iam. Burnaby, British Columbia August 2004 Approval ................................................................................................................ ...ii Abstract ................................................................................................................. 111 Dedication ............................................................................................................. iv Acknowledgemen& ................................................................................................. v Table of Conten& .................................................................................................. vii Lkt of Tables ......................................................................................................... IX List of Bgures ......................................................................................................... x Chapter 1: Introduction .......................................................................................... 1 Background ................................................................................................. 1 Research Objectives ..................................................................................... 3 Thesis Overview ........................................................................................... 4 Chapter 2: Terrestrial Paleoecology of the Queen Charlotte Islands