Using Phytolith Analysis to Discern Holocene Vegetation Change on Sanak Island, Western Gulf of

120 Pages·2017·12.01 MB·English

Antioch University
AURA - Antioch University Repository and Archive
Student & Alumni Scholarship, including
Dissertations & Theses
Dissertations & Theses
2013
A History of Place: Using Phytolith Analysis to
Discern Holocene Vegetation Change on Sanak
Island, Western Gulf of Alaska
Cricket C. Wilbur
Antioch University - New England
Follow this and additional works at:http://aura.antioch.edu/etds
Part of theBotany Commons,Climate Commons,Geology Commons,Indigenous Studies
Commons,Natural Resources and Conservation Commons,Paleobiology Commons,Paleontology
Commons,Plant Biology Commons, and theTerrestrial and Aquatic Ecology Commons
Recommended Citation
Wilbur, Cricket C., "A History of Place: Using Phytolith Analysis to Discern Holocene Vegetation Change on Sanak Island, Western
Gulf of Alaska" (2013).Dissertations & Theses. 89.
http://aura.antioch.edu/etds/89
This Dissertation is brought to you for free and open access by the Student & Alumni Scholarship, including Dissertations & Theses at AURA - Antioch
University Repository and Archive. It has been accepted for inclusion in Dissertations & Theses by an authorized administrator of AURA - Antioch
University Repository and Archive. For more information, please [email protected], [email protected].
Department of Environmental Studies

DISSERTATION COMMITTEE PAGE

The undersigned have examined the dissertation entitled:

A History of Place: Using Phytolith Analysis to Discern Holocene Vegetation Change on
Sanak Island, Western Gulf of Alaska

presented by Cricket C Wilbur, candidate for the degree of Doctor of Philosophy and
hereby certify that it is accepted*.

Committee Chair: James W. Jordan, Ph.D., Department of Environmental Studies,
Antioch University New England, Keene, NH.

Committee Member: Charles G. Curtin, Ph.D., Department of Environmental Studies,
Antioch University New England, Keene, NH.

Committee Member: Deborah M. Pearsall, Ph.D., Department of Anthropology,
University of Missouri, Columbia, MO.

Defense Date: June 13, 2013

Date Submitted to the Registrar’s Office:

*Signatures are on file with the Registrar’s Office, Antioch University New England.

A History of Place:
Using Phytolith Analysis to Discern Holocene
Vegetation Change on Sanak Island,
Western Gulf of Alaska

by

Cricket C. Wilbur

A dissertation submitted in partial fulfillment of
the requirements for the degree of

DOCTOR OF PHILOSOPHY

In

Environmental Studies

at

Antioch University New England

2013
Copyright 2014 Cricket C. Wilbur

All rights reserved
i

ACKNOWLEDGEMENTS

The community of support I very graciously received from my committee, faculty, staff,
fellow classmates, colleagues and friends, co-workers and especially my family made this
project possible.
My thesis advisor, James Jordan, gave me a wonderful opportunity to be part of
his research program in Southwest Alaska. I would like to thank Jim and the rest of my
thesis committee, Deborah Pearsall and Charles Curtin for their guidance throughout the
research and writing of this thesis.
In addition this project would not have been possible without the support of the
many people who provided me samples from Sanak Island and who assisted me with
sample processing. Bruce Finney shared his Sanak Peak Lake sediment core and Nancy
Huntly her Sanak Island plant samples. Sandstone Archaeology and the PaleoResearch
Institute processed the sediment samples for fossil phytoliths. The Antioch University
New England (AUNE) Herbarium provided plant materials and, equipment and supplies
for this project.
It was a privilege to be a student in the Environmental Studies Department at
AUNE. The faculty and staff were very helpful and supportive. I’d like to thank my
classmates who made this a wonderful experience. I am also grateful to my cohort for
their friendship and interesting conversations.
Finally, I would like to thank my family Dean, Kelly and Sam, and my parents for
their enduring support, encouragement, and patience throughout this project.
Financial support for this project was provided in part by NSF Grant 0508101
BE/CNH: Complex Ecosystem Interactions over Multiple Spatial and Temporal Scales:
ii

The Biocomplexity of Sanak Island to Principle Investigator Herbert Maschner at Idaho
Sate University, and an AUNE Environmental Studies Department Professional
Development Grant (2013).
iii

ABSTRACT

This study investigated a terrestrial climate proxy, phytoliths, as a complimentary
approach to documenting the dynamics of present and past vegetation on Sanak Island,
the largest island in a small island group in the eastern Aleutian archipelago, and as a new
basis by which to interpret Holocene environmental variability in Alaska. A phytolith
reference collection was established from 59 selected plant species of maritime tundra
belonging to 27 families. The grass species and a sedge species produced abundant
phytolith forms whereas the majority of dicotyledons in this study were trace producers
of phytoliths. A paleoenvironmental reconstruction from fossil phytoliths recovered from
a continuous lake sediment core indicates that sedges and cool season grasses were
present on this landscape throughout most of the Holocene suggesting the long-term
dominance of maritime climate on island vegetation. Adaptation and resilience of the
modern vegetation on Sanak Island to a warming climate is suggested by the densities of
silicified stomata recovered from six species of grasses, one species of fern, and one
species of horsetail when compared to the paleoenvironmental reconstruction. The
changes in stomata frequency in the plants on Sanak Island today may have connections
to future changes in regional and global climate through the water cycle. Our changing
climate is forcing ecosystems to migrate, acclimate or go extinct demonstrating that new
insights into ecosystem responses to present and past environmental variation, and
forecasting future ecological change are especially relevant today for ecologic and
economic sustainability. The electronic version of this Dissertation is at OhioLink EDT
Center, www.ohiolink.edu/etd.
iv

TABLE OF CONTENTS

ACKNOWLEDGEMENTS i

ABSTRACT iii

LIST OF FIGURES AND TABLES vi

CHAPTER 1: Introduction 1
Introduction
Research Goals & Objectives
Conclusions
References

CHAPTER 2: Phytolith Assemblages in Tundra Plants from Sanak Island, 15
Western Gulf of Alaska
Abstract
Introduction
Setting
Methods
Results
Discussion
Conclusions
References

CHAPTER 3: A Lacustrine Phytolith Record from Western Alaska as 49
a Proxy for Climate Variability during the Holocene
Abstract
Introduction
Study Site
Methods
Results
Discussion
Conclusions
References
v

CHAPTER 4: Silicified Stomata Complexes in Maritime Tundra Plants 79
from Sanak Island, Western Gulf of Alaska suggest response
to changes in Atmospheric CO Concentrations
2
Abstract
Introduction
Setting
Methods
Results
Discussion
Conclusions
References

CHAPTER 5: Conclusions 104
Summary
References

APPENDIX
Copyright Permissions 108