nunataks and island biogeography in the alaska-canada boundary range

225 Pages·2007·4.41 MB·English

NUNATAKS AND ISLAND BIOGEOGRAPHY IN THE ALASKA-CANADA BOUNDARY
RANGE: AN INVESTIGATION OF THE FLORA AND ITS IMPLICATIONS FOR
CLIMATE CHANGE

by

POLLY BASS
(Under the Direction of Elgene O. Box)

ABSTRACT
A baseline flora of the nunataks, isolated peaks and ridges protruding above glaciers, is
developed for the Juneau Icefield. Nunatak and periglacial sites from adjacent areas in Alaska,
northern British Columbia, and the Yukon are included. Key sites are investigated
phytosociologically and biogeographically. Species richness is considered in relation to winter
low temperature, dominant aspect of the study sites, growing-season length, latitude, elevation,
the distance of the sites from the continuously vegetated mainland, and the surface area of the
study sites. The nunatak habitats are tested against the tenets of the theory of island
biogeography. Though difficult in the time frame of the study (approximately seven years) to
draw conclusions on extinction and immigration rates, it is possible to identify species not
observed in previous investigations. It is also possible to observe the relationship between
richness and nunatak surface area, and richness and the distance of a given nunatak from the
continuously vegetated mainland. Surface area of the sites is the variable most correlated with
species richness. This finding is in agreement with the theory of island biogeography. Latitude,
elevation, and growing-season length are further found to have a strong influence on the richness
of the vascular plant assemblages. Species richness has more than doubled from 1948 to 2007, in
parallel with a recorded increase in the mean annual temperature of the region over the same
time period. The floristic data facilitate monitoring the region for further changes. The geobotany
of the northern Alaska-Canada Boundary Range harbors significant information on the past,
current and future effects of climate change on sub-Arctic and alpine vegetation.

INDEX WORDS: Nunatak, Island biogeography, Phytosociology, Floristic richness, Juneau
Icefield, Alaska-Canada Boundary Range, Sub-Arctic vegetation, Alpine
vegetation, Temperature change
NUNATAKS AND ISLAND BIOGEOGRAPHY IN THE ALASKA-CANADA BOUNDARY
RANGE: AN INVESTIGATION OF THE FLORA AND ITS IMPLICATIONS FOR
CLIMATE CHANGE

by

POLLY BASS
B.S., University of the South, 1997
M.Ed., Georgia Southwestern University, 2000

A Dissertation Submitted to the Graduate Faculty of The University of Georgia in Partial
Fulfillment of the Requirements for the Degree

DOCTOR OF PHILOSOPHY

ATHENS, GEORGIA
2007
© 2007
Polly Bass
All Rights Reserved
NUNATAKS AND ISLAND BIOGEOGRAPHY IN THE ALASKA-CANADA BOUNDARY
RANGE: AN INVESTIGATION OF THE FLORA AND ITS IMPLICATIONS FOR
CLIMATE CHANGE

by

POLLY BASS

Major Professor: Elgene O. Box

Committee: Ervan G. Garrison
Vernon G. Meentemeyer
Fausto O. Sarmiento
Wendy B. Zomlefer

Electronic Version Approved:

Maureen Grasso
Dean of the Graduate School
The University of Georgia
December 2007
iv

DEDICATION
This dissertation is dedicated to the following special friends and associates who have
passed on and now belong to the ages but who have made the world a better place for their
having been in it. They have enriched my life and bolstered my dedication to keep striving every
day. These include Dr. James H. Anderson, Dr. Eugene Odum, Dr. Calvin J. Heusser, Mrs. Joan
Miller, Mr. Tony Coburn, Dr. Molly O. Ahlgren, Dr. Arthur Gittins, Dr. George Williams, Mr.
Tom Bingam, Mr. Chris Cochran, Mrs. Vivian Norris, Mr. Fred Bass, Mrs. Mabre Stephens
Bass, Mrs. Rose Jones, Mrs. Mary Servella, Mr. Goran Krop, Mr. Alex Lowe, and Dr. Bruce
Haines.
v

ACKNOWLEDGEMENTS

Many people have lent their time, support and encouragement to this study. I would like
to thank the special people and organizations who have contributed to this project in one way or
another. Numerous persons have assisted with editing and field assistance among other tasks.
These include Dr. Maynard Miller, the Juneau Icefield Research Program, and the Foundation
for Glacier and Environmental Research for their support and encouragement over many years. I
add with deep appreciation, Dr. Robert A. Norris (for instilling an inspiration for field botany
and a love of the herbarium), Dr. Elgene O. Box, Dr. Vernon G. Meentemeyer, Dr. Wendy B.
Zomlefer and the University of Georgia Herbarium, Dr. Fausto O. Sarmiento, Dr. Ervan G.
Garrison, Jill Coburn, Dennis Lewin, Stephen C. Lawrie, Dr. Isabel Ahlgren, Dr. Cliff Ahlgren,
Jean Buck, Howie Langeveld, Gary Linder, Toby Dittrich, Stephanie Bales, Todd and Scooby
Buxton, Dr. Hap Tietjen, Dr. Alexis Wenner, Mary Stensvold, and Brad Kriekhaus. I also thank
Tiesha Cooks, Ryan Mairs; Lubomir Tichy for assistance with JUICE software and
phytosociology; Volker Mell and Tony Heerema for HTML map assistance; Chuck and Blanch
Eiliff, Elaine Strelow, Susan Stanford, Scott McGee, Prof. Werner Stepenhauber, Bob Brown,
Maggie Auble, Melanie Schimmiz, Jessica Drees, Dr. Phil Druker, Pete Lamb, Sampson Chen,
Pablo Wainstein, Natalie Silverton, Dr. Donald Friend, Cyndol Claycamp; Amy Peeke, and
Amber Bean Carter. Also appreciation is extended to the Geologic Survey of Greenland and
Denmark for assistance in locating archival publications; as well as to Carolyn Parker and the
University of Alaska Herbarium; Jacqueline Foss; Dr. Burt Carter, Yonnie Williams, Dr. Bob
Herrington, and to Dr. Michelle Smith for use of the Georgia Southwestern Herbarium; and
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appreciation too to Dr. Cathy Connor, Dr. Clair Connell, Dr. Anne Glauser; Dr. Donald Walker
and Dr. Dave Murray for helpful discussion of field sampling techniques and design. Finally,
thanks go to the Philanthropic Educational Organization and the PEO Arizona chapter, the
American Alpine Club and Dr. Bill Isherwood, Dr. Richard Keen, Dr. Naresh Kumar, Dr. N.
Kahlequazzaman, Dr. Paul Bischoff, the University of Georgia Graphics Department; Monica
Petrokowski of the UGA Science Library Reference Desk; Dr. Alicia Lesnikowska; Jim Case,
Lisa Matlock, and Ellen Anderson of the U.S. Forest Service, Tongass National Forest; Steve
Henrikson and Donna Baron of The Alaska State Museum; Ginny Blackson of the Stratton
Library of Sheldon Jackson College; and Joe Liddle for statistical analysis software. Most
helpful too have been the library and archives of Sheldon Jackson College and the University of
Washington, as well as the University of Idaho Library, and the research library of the
Glaciological and Arctic Sciences Institute.
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TABLE OF CONTENTS
Page
ACKNOWLEDGEMENTS.............................................................................................................v
LIST OF TABLES.........................................................................................................................xi
LIST OF FIGURES.....................................................................................................................xiii
CHAPTER
1 INTRODUCTION.........................................................................................................1
Overview........................................................................................................................1
Research Hypotheses.....................................................................................................1
Site Description..............................................................................................................3
Data................................................................................................................................8
Expected Results..........................................................................................................10
2 BACKGROUND.........................................................................................................11
The Diversity and Origin of Alpine and High Latitude Plant Species........................11
Island Biogeography and Vascular Plant Species........................................................11
Perspectives on Climate Change and Vegetation .......................................................13
Climate Change and Alpine Plant Species...................................................................16
The Nunatak Hypothesis and Tabula Rasa..................................................................20
Ptarmigan Ridge Geobotany........................................................................................23
viii
3 METHODOLOGY......................................................................................................24
Methodological Background........................................................................................24
Phytosociological Analysis..........................................................................................28
Partial Table Sorting....................................................................................................31
Tabular Analysis and Sorting in JUICE and SAS.......................................................33
Sequential Steps Taken in Relevé Analysis.................................................................33
Line Transects..............................................................................................................38
Species-Area Curves ...................................................................................................39
Modeling Principles.....................................................................................................39
Hypothetical Models ...................................................................................................40
Latitude and Elevation Regressions.............................................................................41
Temperature Data Formatting .....................................................................................42
Temperature Per Site 1999-2006.................................................................................43
Growing-Season Data..................................................................................................45
Compilation of Temperature and Richness Data for Studies from 1948-Present........46
Aspect Data Compilation.............................................................................................46
Comparison of Sites in Historical Studies and the Current Study ..............................47
Ptarmigan Ridge Geobotany........................................................................................47
4 RESULTS AND ANLYSES........................................................................................48
Phytosociology.............................................................................................................48
Floristics.......................................................................................................................55
Tabular Analysis of Relevés........................................................................................61
Community Identification from Tabular Analysis.......................................................61