factors determining habitat selection by spring migrating waterfowl along the wabash river, illinois

186 Pages·2015·1.87 MB·English

Southern Illinois University Carbondale
OpenSIUC
Dissertations Theses and Dissertations
12-1-2014
FACTORS DETERMINING HABITAT
SELECTION BY SPRING MIGRATING
WATERFOWL ALONG THE WABASH RIVER,
ILLINOIS
Ryan O'Shaughnessy
Southern Illinois University Carbondale, [email protected]
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Recommended Citation
O'Shaughnessy, Ryan, "FACTORS DETERMINING HABITAT SELECTION BY SPRING MIGRATING WATERFOWL ALONG
THE WABASH RIVER, ILLINOIS" (2014).Dissertations.Paper 962.
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FACTORS DETERMINING HABITAT SELECTION BY SPRING MIGRATING
WATERFOWL ALONG THE WABASH RIVER, ILLINOIS

By
Ryan O'Shaughnessy
B.Sc. University of the Witwatersrand, Johannesburg, South Africa, 2003
B.Sc. with Honors, University of the Witwatersrand, Johannesburg, South Africa, 2006
M.Sc. University of the Witwatersrand, Johannesburg, South Africa, 2010

A Dissertation
Submitted in Partial Fulfillment of the Requirements for the
Doctor of Philosophy

Department of Zoology
In the Graduate School
Southern Illinois University Carbondale
December, 2014
DISSERTATION APPROVAL

FACTORS DETERMINING HABITAT SELECTION BY SPRING MIGRATING
WATERFOWL ALONG THE WABASH RIVER, ILLINOIS

By
Ryan O'Shaughnessy

A Dissertation Submitted in Partial
Fulfillment of the Requirements
for the Degree of
Doctor of Philosophy
in the field of Zoology

Approved by:
Michael W. Eichholz, Chair
Eric M. Schauber
Clayton K. Nielsen
James R. Lovvorn
Joshua D. Stafford

Graduate School
Southern Illinois University Carbondale
4 November, 2014
AN ABSTRACT FOR THE DISSERTATION OF
RYAN O’SHAUGHNESSY, for the Doctor of Philosophy Degree in Zoology, presented on 28
February, 2014, at Southern Illinois University Carbondale.
TITLE: FACTORS DETERMINING HABITAT SELECTION BY SPRING MIGRATING
WATERFOWL ALONG THE WABASH RIVER, ILLINOIS
MAJOR PROFESSOR: Michael W. Eichholz
The main proponent of management of any animal species is habitat management. The
ability of habitats to maintain species communities will depend on the variation in both habitat
structure and composition. While spatial variation in habitat resources plays a critical role in
determining the distribution of species, an equally important consideration that must be
accounted for is temporal variation in the needs of the target species. Nutritional requirements,
and thus the habitats used to fulfil those nutritional needs, will be different depending on if the
individual is breeding, migrating, molting, enduring winter, or establishing a new range.
For waterfowl, we currently assume that winter and migration are nutritionally stressful
and are consequently the periods most limiting to populations. The theory of ideal free
distribution assumes that animals distribute themselves according to the factor most limiting to
their fitness. In the case of non-breeding waterfowl, this factor is believed to be food. We
assume if habitats with abundant food resources are provided, waterfowl will make use of those
habitats. Deviations from an ideal free distribution based on food become problematic for
managers since these deviations will keep some areas from being exploited to their potential,
while other areas may become over-exploited. Recent observations have made it clear that this
assumption may need to be reconsidered for effective waterfowl management. In this
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dissertation I quantitatively examine the degree to which spring migrating waterfowl conform to,
or deviate from, an ideal free distribution based on food. Since food availability was not
expected to account for 100% of waterfowl distribution, I further investigated what other
potential habitat components influence the distribution of spring migrating waterfowl.
In the first chapter of this dissertation, I explicitly tested the influence of food availability
on waterfowl distribution. A series of paired 0.42 ha (1 acre) plots were established in various
habitat types. One plot in each pair was treated with corn to a density of 2000 kg/ha, while the
remaining plot was used as a control. Background food availability was controlled for by taking
core samples from each plot, and estimating the natural seed and invertebrate biomass. The
abundance each species of waterfowl using the plots was recorded during morning and afternoon
observation periods. Linear mixed models were used to assess how variations in food
availability influenced distribution of waterfowl. Although the waterfowl community showed a
significant preference for treatment plots, our ability to influence abundance was low. Food
availability accounted for minimal variation in abundance of the waterfowl community as a
whole or for each focal species.
Since the results of the first chapter showed food availability to be a poor predictor of
waterfowl distribution, in the second chapter I set out to determine other potential habitat
variables could be responsible for driving waterfowl distribution during spring migration. After
each observation period, a series of habitat structural measurements were made within each
paired plot. Habitat measurements included water characteristics, vegetation structure,
vegetation type, habitat type, and weather conditions. Linear mixed models and model selection
were employed to determine which of the habitat characteristics showed the greatest ability to
predict waterfowl abundance on study plots. Models containing precipitation and Wabash River
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flood stage predictor variables were the best performing, and were the best predictors of
waterfowl abundance on study plots. The results from this chapter encouraged investigation into
how environmental factors shape the formation of local duck communities are structured from
regional pools.
In the third chapter of this dissertation I investigate the relationship between local and
regional waterfowl community structure and how this relationship is mediated through
environmental filters which dictate what proportion of the regional species pool exists at local
scales. To address this relationship, I tested three hypotheses: 1) resource availability drives
species diversity at local scales; 2) similarity between local and regional habitats will result in a
similar species community occurring at both scales, and; 3) increased heterogeneity of local
habitat structure will result in more diverse waterfowl communities at local scales. I used
Mahalanobis distance and cumulative standard deviation of habitat variables in conjunction with
mixed models and model selection to compare hypotheses and determine which had the greatest
potential for mediating local community structure from regional pools. Increasing resource
abundance appeared to have the greatest influence over local duck diversity, but the model
indicated that although species diversity could be increased by increasing food abundance,
diversity at local scales would become saturated before becoming representative of the regional
community.

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ACKNOWLEDGEMENTS
I would like to thank all of the technicians that worked on this project, both in the field
and in the lab. Without Glen Niebaum, Kelly Kerfeld, Andy Gilbert, Clark Nissley, Lisa Clark,
Ryan Lovell, Meghan Oberkircher, Brenna Towery, Kristen Linner, Trevor Laine, Derek Danner
and Jimmy Doyle we never would have been to collect the field data we needed. I’m sure most
of them would agree that if we ever collect another core sample again, it’ll be too soon. I thank
all our laboratory technicians whom all spent countless hours at the Wildlife Annex processing
core samples, unfortunately there are just too many of you to list individually. Special mention
must however be extended to Jess Suda who did a fantastic job over-seeing all processing
operations over the past few years.
The knowledge, guidance, and humor of my advisor Mike Eichholz is something that I
will be forever grateful for. Mike, maybe just for a moment I could be ‘Number 1’? I will
always appreciate the support and direction given to me by the rest of my committee, Jim
Lovvorn, Clay Nielson, Eric Schauber, and Josh Stafford – especially during prelims.
This project would not have been possible without Ray McCormick, Bill Siddens, Mike
Seitzinger, Cindi and Rusty Morris, Mark Grundman, Dennis Williams, Mike Crowder, Chris
Walkonowski, Don and Ruth Lathrop, Steve Lathrop, Larry Cox, Allen Gray, Matt Campbell,
Tim Ervin, Susan McCormick, David Allen, Danny Harris, Steve Scates Jnr., and Matt Duffy,
the Illinois Landowners who graciously allowed us to conduct our research in their wetlands. I
would especially like to thank the Duffy family for accommodating us each field season. Matt,
we’ll return the favor in Botswana someday. My gratitude also goes to the Illinois Department
of Natural Resources and my funding source Federal Aid Grant W-158-R.
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My fellow students in the Cooperative Wildlife Research Laboratory provided an endless
source of knowledge, support and humor. I have made many long lasting friendships, and I hope
to work with many of you in the future. The day to day operations of the lab would not have
been possible without the hard work provided by Susan Dallas, Jane Elders, Teresa Shirk, Nancy
Smith, and Judy Rains – my thanks go to all of you.
I am especially grateful for all the hard work and help provided by Adam Behney.
We’ve struggled through extreme weather and frustrating technicians to collect and analyze all
the data for this project. Most notably, I don’t think many people will understand me the way
Adam does when I say “I hate core samples” and “I love hula-hoops”. Adam, I’ll be your
partner anytime! Thank you for everything, I hope to work with you again in the future.
Lastly, I would like to thank my family. Chet and Cheryl, thank you for providing the
love and support to both Kara and I as continued along our journey in Southern Illinois. Thank
you for providing a roof over our heads when we arrived from Africa. To my parents, mom, dad
and Gabi, I think I may now be finished studying. Thank you for instilling in me an ethic to set
goals, work hard, and accomplish my dreams. Without your emotional and financial support
none of this would have been possible. Most importantly, my wife Kara, you have been my rock
through thick and through thin. Your encouragement, love, and support mean more to me than
you’ll ever know. We’ve travelled the world together, and you’ve given me the most beautiful
daughter a father could ask for. Thank you Kara and Riley, I love you both.

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TABLE OF CONTENTS
PAGE
ABSTRACT i
ACKNOWLEDGEMENTS iv
LIST OF TABLES viii
LIST OF FIGURES xiv
CHAPTER 1 – A TEST OF THE ASSUMPTIONS OF THE IDEAL FREE DISTRIBUTION
AND MARGINAL VALUE THEOREM IN SPRING MIGRATING WATERFOWL
INTRODUCTION 1
MATERIALS AND METHODS 6
Study Area 6
Study Design and Data Collection 6
Data Analyses 9

RESULTS 15
DISCUSSION 19
TABLES 27
FIGURES 34
CHAPTER 2 – DETERMINING FACTORS INFLUENCING DISTRIBUTION OF SPRING
MIGRATING WATERFOWL: FORAGING, PREDATION, OR WEATHER?
INTRODUCTION 41
MATERIALS AND METHODS 48
Study Area 48
Study Design and Data Collection 49
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Data Analyses 54
RESULTS 61
DISCUSSION 64
TABLES 75
FIGURES 89

CHAPTER 3 – THE INFLUENCE OF ENVIRONMENTAL FACTORS ON LOCAL-
REGIONAL COMMUNITY STRUCTURE IN SPRING MIGRATING WATERFOWL
INTRODUCTION 90
MATERIALS AND METHODS 94
Study Area 94
Study Design and Data Collection 95
Data Analyses 100
RESULTS 106
DISCUSSION 108
TABLES 113
FIGURES 119
REFERENCES 123
APPENDICES
APPENDIX 1 150
APPENDIX 2 156
VITA 166
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