SPATIAL AND TEMPORAL CHANGES IN REPTILE AND AMPHIBIAN POPULATIONS IN A ...

136 Pages·2017·2.37 MB·English

SPATIAL AND TEMPORAL CHANGES IN REPTILE AND AMPHIBIAN
POPULATIONS IN A SUBURBAN
GREENBELT IN WILLIAMSON
COUNTY, TEXAS
By
John M. Wamsley, B.A., M.A.Geo

A dissertation submitted to the Graduate Council of
Texas State University in partial fulfillment
of the requirements for the degree of
Doctor of Philosophy with a major in
Environmental Geography
May 2017

Committee Members:
David R. Butler, Chair
Richard W. Dixon
Timothy Bonner
Kimberly Meitzen
COPYRIGHT
by
John M. Wamsley
2017
FAIR USE AND AUTHOR’S PERMISSION STATEMENT

Fair Use

This work is protected by the Copyright Laws of the United States (Public Law 94-553,
section 107). Consistent with fair use as defined in the Copyright Laws, brief quotations
from this material are allowed with proper acknowledgment. Use of this material for
financial gain without the author’s express written permission is not allowed.

Duplication Permission

As the copyright holder of this work I, John M. Wamsley, authorize duplication of this
work, in whole or in part, for educational or scholarly purposes only.
DEDICATION

I would like to dedicate this dissertation to my mother and late father, Beverly Ann
Martin and John Eldon Wamsley, my late grandmother Helen G. Wamsley, and
especially my children John Ross and Catherine Michelle Wamsley, whom I hope will be
inspired to achieve things for which their abilities are best suited.
.
ACKNOWLEDGEMENTS

I would like to acknowledge the dedicated service of my advisor, David R. Butler, and
committee members, Richard W. Dixon, Timothy Bonner, and Kimberly Meitzen,
without whose support this project would not have been possible. I would also like to
acknowledge and thank Allison Glass-Smith for her assistance, making sure all
procedures were properly followed in accordance with departmental guidelines.
I would like to thank John R. and Catherine Wamsley for their assistance with the
fieldwork associated with this project. I would also like to thank Connor and Culton
Rosenbeck, and Joshua N. Moehring for their contributions to the field studies involved
in this project. I would especially like to thank my wife, Nancy E. Wamsley, for her
patience and willingness to take the wheel while I jumped out of vehicles to positively
identify specimens.

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TABLE OF CONTENTS

Page
ACKNOWLEDGEMENTS ............................................................................................... v
LIST OF TABLES .......................................................................................................... viii
LIST OF FIGURES .......................................................................................................... ix
ABSTRACT ....................................................................................................................... x

CHAPTER
I. INTRODUCTION ............................................................................................. 1
Objective .................................................................................................... 8

II: LITERATURE REVIEW ................................................................................ 10
Methods for Tracking Reptile Movements .............................................. 10
Roadway Mortality .................................................................................. 14
Effects of Weather and Climate on Amphibians ..................................... 21

III: STUDY AREA AND DEFINITIONS ........................................................... 22
Terminology ............................................................................................. 22
Changes in Nomenclature ........................................................................ 23
Study Area ............................................................................................... 24

IV: METHODS .................................................................................................... 31
V: DATA AND RESULTS ................................................................................ .40
Results ...................................................................................................... 48

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Page
VI: DISCUSSION AND CONCLUSION ........................................................... 50
Associated Future Research ..................................................................... 52

APPENDIX SECTION .................................................................................................... 53

WORKS CITED ............................................................................................................ 118

vii
LIST OF TABLES
Table Page
1. Changes in Nomenclature ............................................................................................ 23
2. Shannon Diversity Index Calculations for the Duration of the Study ......................... 42
3. Statistical Summary of Three Representative Years Using the Shannon Diversity
Index. ........................................................................................................................... 43
4. Reptile and Amphibian Observations in Relation to Annual Rainfall ......................... 45
5. Percentage of Observations that were Non-native Species .......................................... 47

viii
LIST OF FIGURES

Figure Page
1. Williamson County, Texas........................................................................................... 24
2. Aerial View of Study Area with the Dry Lake Bed Tagged ........................................ 24
3. Topographic Map of the Study Area ........................................................................... 25
4. San Gabriel River Ranch Lake (Full) .......................................................................... 26
5. San Gabriel River Ranch Lake (Dry) ........................................................................... 27
6. Lackey Creek Below the Dam (Flowing) .................................................................... 28
7. Lackey Creek Below the Dam (Dry) ........................................................................... 29
8. Category 1: Obligate Hydric Species. .......................................................................... 33
9. Category 2: Hydric/Mesic/Xeric Facultative Species .................................................. 34
10. Category 3: Reproductively Hydric Obligate Species ............................................... 35
11. Category 4: Hydric Obligate Forager Species .......................................................... 36
12. Category 5: Xeric Species .......................................................................................... 37
13. Xeric Species ............................................................................................................. 38
14. Xeric Species ............................................................................................................. 39

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ABSTRACT
Changes in climate and human habitat usage can lead to changes in population sizes and
dynamics of reptiles and amphibians in a given microhabitat. This project was an effort to
document those changes over a twenty year period in a suburban greenbelt in Williamson
County, Texas. Numerous factors, including flooding and extended periods of drought, as
well as encroaching human development and associated motorized vehicular traffic,
affected the reptile and amphibian populations in the study area during the years that
were examined and recorded. Though not intended as part of the original study, the
invasion and establishment of an introduced species was also documented.

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