Louisiana State University LSU Digital Commons LSU Historical Dissertations and Theses Graduate School 1981 Thermal and Spatial Ecology of Three Species of Water Snakes (Nerodia) in a Louisiana Swamp. Thomas Claud Michot Louisiana State University and Agricultural & Mechanical College Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_disstheses Recommended Citation Michot, Thomas Claud, "Thermal and Spatial Ecology of Three Species of Water Snakes (Nerodia) in a Louisiana Swamp." (1981). LSU Historical Dissertations and Theses. 3694. https://digitalcommons.lsu.edu/gradschool_disstheses/3694 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Historical Dissertations and Theses by an authorized administrator of LSU Digital Commons. For more information, please contact [email protected]. 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In all cases we have filmed the best available copy. University Microfilms International 300 N. ZEES RD., ANN ARBOR, Ml 48106 8207833 Michot, Thomas Claud THERMAL AND SPATIAL ECOLOGY OF THREE SPECIES OF WATER SNAKES (NERODIA) IN A LOUISIANA SWAMP The Louisiana State University and Agricultural and Mechanical ColPh.D. 1981 University Microfilms International 300 N. Zeeb Road, Ann Arbor, M l 48106 PLEASE NOTE: In all cases this material has been filmed in the best possible way from the available copy. Problems encountered with this document have been identified here with a check mark V . 1. Glossy photographs or pages______ 2. Colored illustrations, paper or print______ 3. Photographs with dark background______ 4. Illustrations are poor copy______ 5. Pages with black marks, not original copy______ 6. Print shows through as there is text on both sides of page______ 7. Indistinct, broken or small print on several pages A-"'" 8. Print exceeds margin requirements______ 9. Tightly bound copy with print lost in spine______ 10. Computer printout pages with indistinct print______ 11. Page(s)____________lacking when material received, and not available from school or author. 12. Page(s)____________seem to be missing in numbering only as text follows. 13. Two pages numbered_____________. Text follows. 14. Curling and wrinkled pages 15. Other________________________________________________________________________ University Microfilms International THERMAL AND SPATIAL ECOLOGY OP THREE SPECIES OP WATER SNAKES (NERODIA) IN A LOUISIANA SWAMP. A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment of the requirements for the degree of Doctor of Philosophy in The Department of Zoology and Physiology by Thomas Claud Michot .S., University of Southwestern Louisiana, 1972 M.S., Utah State University, 1976 December 1981 ACKNOWLEDGMENTS The Petroleum Refiners Environmental Council of Louis­ iana and the Louisiana State University Department of Zoology and Physiology provided partial financial support for this study. I would like to thank my major professor. Dr. Henry R. Mushinsky, for his advice and support during the research project, and Dr. Walter J. Harman for serving as my major professor in Dr. Mushinsky's absence. Committee members, Dr. J. Michael Fitzsimons, Dr. Douglas A. Rossman, and Mr. John D. Newsom, provided critical reviews of the dissertation. Dr. James J. Hebrard helped with the field work and interpretation of results, for which I am grateful. I would like to thank Grace Meleton and Kay Michot for their help with the typing, and Kay for her special support and encouragement. This work is dedicated to Andre and Louis: may they never lose the desire to understand. Thomas Claud Michot TABLE OF CONTENTS Page ACKNOWLEDGMENTS................................... ij LIST OF TABLES.................................... yi LIST OF FIGURES.................................... vii± ABSTRACT........................................... ix INTRODUCTION...................................... 1 MATERIALS AND METHODS............................. 5 Study Area........................................ 6 Data Collection................................... 7 Data Analysis..................................... 11 Thermal Ecology................................ 11 The Effect of Temperature on Choice of Microhabitat................................ 11 Sources of Variation in Thermal Micro­ habitat Optimization..................... 11 Thermal Microhabitat Optimization Versus Microhabitat Use Patterns........ 16 Body Temperature Variation.................. 17 Relationship Between Body Temperature and Ambient Temperature.................. 17 Interaction Between Thermal Noncon­ formity and Thermal Microhabitat Optimization............................. 19 Solar Effects............................ 19 Time Effects............................. 20 Body Temperature Variation Over Time.................................. 20 Thermoregulatory Categories.......... 21 Effect of Microhabitat Change........ 22 Eccritic Body Temperatures............. 23 Spatial Ecology................................ 24 Land/Water Relations........................ 24 Linear Movement Patterns.................... 26 Movement Rates........................... 26 Daily Activity........................... 28 Planar Movement Patterns.................... 28 Home Range......... 28 Movements Within Home Range............... 28 RESULTS............................................ 31 Thermal Ecology................................... 31 The Effect of Temperature on Choice of Microhabitat................................... 31 Sources of Variation in Thermal Micro­ habitat Optimization........................ 31 Thermal Microhabitat Optimization Versus Microhabitat Use Patterns................... 42 Body Temperature Variation..................... 49 Relationship Between Body Temperature and Ambient Temperature..................... 49 Interaction Between Thermal Nonconform­ ity and Thermal Microhabitat Optimiza­ tion........................................ 52 Summer................................... 52 Spring/Fall.............................. 55 Winter................................... 57 Summary of Species Differences.......... 61 Solar Effects............. 63 Time Effects................................ 63 iv Body Temperature Variation Over Time.... 70 Thermoregulatory Categories............ 73 Effect of Microhabitat Change........... 73 Eccritic Body Temperatures 7 5 Spatial Ecology.................................. 81 Land/Water Relations.......................... 81 Linear Movement Patterns...................... 86 Movement Rates............................. 86 Daily Activity............................. 89 Planer Movement Patterns...................... 90 Home Range........................... 90 Movements Within Home Range............... 94 DISCUSSION....................................... 108 Thermal Ecology............................... 109 Spatial Ecology............................... 124 LITERATURE-CITED................................. 129 APPENDIX......................................... 144 VITA............................................. 147 v LIST OP TABLES Page Table 1. Sex and size characteristics of snakes used in telemetry study................. 9 Table 2. Thermal statistics of three species of water snakes in a gradient (after Walley and Mushinsky, in press)............... 13 Table 3. Analysis of varience in thermal micro­ habitat optimization (TMO) for three species of Nerodia...................... 32 Table 4 Mean thermal microhabitat optimization (TMO) values for water snakes by species, light, and