Avian Community Ecology: Patterns of Co-occurrence, Nestedness, and Morphology

202 Pages·2016·0.86 MB·English

by  Michael David Collins

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Doctoral Dissertations Graduate School
12-2006
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Michael David Collins
University of Tennessee - Knoxville
Follow this and additional works at: https://trace.tennessee.edu/utk_graddiss
Part of the Ecology and Evolutionary Biology Commons
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Collins, Michael David, "Avian Community Ecology: Patterns of Co-occurrence, Nestedness, and
Morphology. " PhD diss., University of Tennessee, 2006.
https://trace.tennessee.edu/utk_graddiss/1927
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To the Graduate Council:
I am submitting herewith a dissertation written by Michael David Collins entitled "Avian
Community Ecology: Patterns of Co-occurrence, Nestedness, and Morphology." I have examined
the final electronic copy of this dissertation for form and content and recommend that it be
accepted in partial fulfillment of the requirements for the degree of Doctor of Philosophy, with a
major in Ecology and Evolutionary Biology.
Daniel Simberloff, Christine R. B. Boake, Major Professor
We have read this dissertation and recommend its acceptance:
David Buehler, Sergey Gavrilets, Louis J. Gross
Accepted for the Council:
Carolyn R. Hodges
Vice Provost and Dean of the Graduate School
(Original signatures are on file with official student records.)
To the Graduate Council:

I am submitting herewith a dissertation written by Michael David Collins entitled “Avian
Community Ecology: Patterns of Co-occurrence, Nestedness, and Morphology.” I have
examined the final electronic copy of this dissertation for form and content and
recommend that it be accepted in partial fulfillment of the requirements for the degree of
Doctor of Philosophy, with a major in Ecology and Evolutionary Biology.

Daniel Simberloff
Major Professor

Christine R. B. Boake
Department Head

We have read this dissertation
and recommend its acceptance:

David Buehler

Sergey Gavrilets

Louis J. Gross

Accepted for the Council:

Anne Mayhew
Vice Chancellor and Dean of
Graduate Studies

(Original signatures are on file with official student records.)
Avian Community Ecology:
Patterns of Co-occurrence, Nestedness, and Morphology

A Dissertation
Presented for the
Doctor of Philosophy Degree
The University of Tennessee, Knoxville

Michael David Collins
December 2006
To my mom and dad. I miss you, Mom.
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ACKNOWLEDGMENTS

Many people have helped me at different stages of this work; without them, this project
would not have been completed. My advisor, Dan Simberloff, provided guidance at all stages and
showed immeasurable patience in allowing me the freedom and time to develop a dissertation of
which I can be proud. My interactions with him have been academically and personally
rewarding, and I extend to him my deepest gratitude. I am still impressed by his fairness,
modesty, and objectivity.
Discussions with colleagues have sharpened my thoughts. In particular, I thank Arijana
Barun, Catherine Sheehy, Diego Vázquez, Howard Horne, Martin Nuñez, Monica Beals, Nate
Sanders, Norris Muth, and Tad Fukami. My dissertation committee, Dan Simberloff, Dave
Buehler, Lou Gross, and Sergey Gavrilets, provided cogent advice, criticism, and direction. Marc
Cadotte, Martin Nuñez, Nate Sanders, Sean Gunter, and my committee critically read sections of
the dissertation. Bruce Ralston, Dean Jue, Jeff Dahoda, Josh Calhoun, Matt Fitzpatrick, Steve
Ahrens, Will Fontanez, and especially Jonathan Witcoski provided advice with GIS. During my
time at the University of Tennessee, Phyllis Bice seemingly ran the department and constantly
impressed me with her ability to solve problems that I had inadvertently created.
I thank my family and friends for their unwavering support and enduring love. Dad,
Steve, Jen, and Mark, Granny, Bart Kicklighter, Howard Horne, Norris Muth, Sean Gunter, and
Tom Kennedy have enriched my life. And lastly, I thank my beautiful wife, Codruţa. I never
could have done this without her. She and I are building a wonderful life together, and I am
grateful for having found her.
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ABSTRACT

A central tenet of the competition paradigm is that community structure is governed by
deterministic rules. The competition paradigm pervades nearly all subdisciplines and extends to
the broadest, deepest questions in ecology. To determine whether patterns of co-occurrence,
nestedness, and morphology in avian communities are consistent with a competition hypothesis, I
use null models to compare observed patterns to patterns expected in the absence of competition.
I use presence-absence matrices of birds in three archipelagoes to test whether species
exhibit exclusive distributions. Congeneric birds co-occur significantly less frequently than
predicted in two archipelagoes, consistent with a competition hypothesis. However, when
examined separately, most genera do not exhibit patterns that differ from random expectations.
Furthermore, species differences in habitat preference and barriers to dispersal within
archipelagoes are two alternate hypotheses that can explain many exclusive patterns and are
supported by available data. Distributional evidence alone does not implicate competition. I argue
that the range of conditions under which competition is likely to generate exclusive distributions
across islands is narrow.
Although nested patterns are viewed as the converse of competitive exclusion, meta-
analyses of presence-absence matrices simultaneously support the ubiquity of exclusive
distributions and indicate that most ecological systems are nested. I show why these apparently
contradictory patterns are not mutually exclusive. Patterns of nestedness can result from multiple
processes; without understanding mechanisms, nestedness analysis is unlikely to prove useful for
conservation.
I study algorithms that randomize presence-absence matrices. Two commonly used
algorithms generate biased statistical distributions and should be abandoned.
I test for community-wide character displacement in wing length and talon size among
Accipiter hawks. I also assess whether subspecific variation in wing length is predictable from
community composition. I find limited evidence of community-wide character displacement for
wing length, but talon size, which relates directly to resource use, shows larger minimum and
more equal size ratios than predicted. I find no evidence of competitively driven change in wing
length. These findings demonstrate the importance of examining traits directly related to function.
I cannot determine whether community-wide character displacement of talon size results from
ecological character displacement, species assortment, or both.

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TABLE OF CONTENTS
1. A COMPARISON OF MATRIX RANDOMIZATION ALGORITHMS.................................1
INTRODUCTION.................................................................................................................1
METHODS............................................................................................................................3
RESULTS..............................................................................................................................5
DISCUSSION.......................................................................................................................7
2. AN EXAMINATION OF SPECIES CO-OCCURRENCE PATTERNS.................................10
INTRODUCTION...............................................................................................................11
METHODS..........................................................................................................................13
RESULTS............................................................................................................................15
DISCUSSION.....................................................................................................................17
3. PATTERNS AND CAUSES OF NESTEDNESS....................................................................27
INTRODUCTION...............................................................................................................28
METHODS..........................................................................................................................31
RESULTS............................................................................................................................35
DISCUSSION.....................................................................................................................36
4. MORPHOLOGICAL PATTERNS IN THE GENUS ACCIPITER.........................................44
INTRODUCTION...............................................................................................................44
METHODS..........................................................................................................................46
RESULTS............................................................................................................................49
DISCUSSION.....................................................................................................................50
LITERATURE CITED..................................................................................................................53
APPENDICES...............................................................................................................................65
A. Tables.............................................................................................................................66
B. Figures..........................................................................................................................113
C. Presence-absence matrix for the Bismarck Archipelago..............................................138
D. Presence-absence matrix for the Solomon Archipelago...............................................146
E. Presence-absence matrix for Vanuatu...........................................................................156
F. Island characteristics for the Bismarck Archipelago.....................................................160
G. Island characteristics for the Solomon Archipelago.....................................................161
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H. Island characteristics for Vanuatu................................................................................163
I. Species characteristics for the Bismarck Archipelago...................................................164
J. Species characteristics for the Solomon Archipelago....................................................171
K. Species characteristics for Vanuatu..............................................................................177
L. Wing length and talon size of accipiters and bird-eating hawks...................................180
M. Wing lengths for subspecies of Accipiter hawks.........................................................183
N. Minimum size ratios and Barton–David statistics........................................................187
VITA............................................................................................................................................190

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LIST OF TABLES

1.1. Presence-absence matrix for finches in the Galápagos Islands...............................................66
1.2. Co-occurrence metrics............................................................................................................67
1.3. Characteristics of matrix randomization algorithms...............................................................68
1.4. ANOVA: Mean C-score.........................................................................................................69
1.5. ANOVA: Variance in C-score................................................................................................70
1.6. ANOVA: Difference between observed C-score and mean C-score......................................71

2.1. Presence-absence matrix for finch species in the Galápagos Islands......................................72
2.2. Co-occurrence measures.........................................................................................................73
2.3. Measures of co-occurrence within taxa..................................................................................75
2.4. Co-occurrence measures: birds of the Bismarck Archipelago................................................76
2.5. Co-occurrence measures: birds of the Solomon Archipelago.................................................77
2.6. Co-occurrence measures: birds of Vanuatu............................................................................78
2.7. Co-occurrence measures: bird families by archipelago..........................................................79
2.8. Co-occurrence measures: bird genera by archipelago............................................................82
2.9. Correlation in co-occurrence measures in bird taxa across archipelagoes..............................85
2.10. Co-occurrence measures for bird families by archipelago: Incidence algorithm..................86
2.11. Co-occurrence measures for bird genera by archipelago: Incidence algorithm....................89
2.12. Hypotheses for nonrandom distribution patterns within genera...........................................92
2.13. Dispersal and niche breadth of supertramps versus congeners.............................................94

3.1. Nested matrix for finches in the Galápagos Islands................................................................95
3.2. Measures of nestedness...........................................................................................................96
3.3. Matrix randomization algorithms for studies of nestedness...................................................97
3.4. Measures of nestedness by randomization algorithm for birds of the Bismarcks...................98
3.5. Measures of nestedness by randomization algorithm for birds of the Solomons....................99
3.6. Measures of nestedness by randomization algorithm for the birds of Vanuatu....................100
3.7. Skewness and kurtosis for measures of nestedness..............................................................101
3.8. Nestedness results when islands are sorted by area or by isolation......................................102
3.9. ANOVA: Species rank nestedness and life history traits in the Bismarcks..........................103
3.10. ANOVA: Species rank nestedness and life history traits in the Solomons.........................104
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