AN ABSTRACT of the THESIS of Michael Stephen Mahr, for The
Total Page:16
File Type:pdf, Size:1020Kb
AN ABSTRACT OF THE THESIS OF Michael Stephen Mahr, for the Master of Science degree in Biology, presented 22 October 2020. Title: Distributions and Statuses of Map Turtles (Graptemys spp.) in Kansas. Thesis chair: Dr. Alexis Powell Abstract approved: _____________________________________________________ Turtles are among the most imperiled groups of organisms across the globe, requiring frequent assessment to monitor healthy populations and manage those in decline. Riverine turtles have been subject to varying degrees of habitat degradation, including damming and channelizing rivers, leading to habitat fragmentation and reduced population connectivity. Assessing the status of isolated or peripheral populations can be difficult if their relationships to other populations, including their taxonomic (i.e. species or subspecies) identities, are unclear or if they utilize habitats different from those typical of the core range. To investigate the distributions and abundances of four map turtle taxa (genus Graptemys) at the edges of their ranges, surveys were conducted in waterways of 36 counties in eastern Kansas in 2017–2019, using baited hoop-nets and visual surveys with telescope and camera. A total of 1646 map turtles were recorded over 1428 trap nights and 42 days of scoping. With respect to the state-threatened G. geographica, previously known from only 18 specimens or vouchered photographs from 12 locations, 92 individuals were detected in visual surveys, six were caught in traps, and two were obtained from local herpetologists. These 100 individuals came from 55 locations, 52 of them where the species had not been documented previously. Survey data were used to estimate relative abundances and absolute densities of Graptemys taxa by drainage. To further evaluate the extent to which individuals of the genus Graptemys group together in Kansas as phenotypically distinct types that correspond to geographically coherent populations and currently recognized taxa, I examined all museum specimens from the state. Many had been incorrectly identified according to currently recognized species limits. Together, survey data and taxonomic reassessment of museum records generated simpler and better resolved patterns of occurrence of Graptemys taxa in Kansas; findings were consistent with existence of four taxa with partially overlapping distributions. Keywords: integumentary color patterning, False Map Turtle Complex, museum specimen reclassification, turtle conservation, visual survey DISTRIBUTIONS AND STATUSES OF MAP TURTLES (GRAPTEMYS SPP.) IN KANSAS ---------- A Thesis Presented to The Department of Biological Sciences EMPORIA STATE UNIVERSITY ---------- In Partial Fulfillment of the Requirements for the Degree Master of Science ---------- by Michael Stephen Mahr 22 October 2020 ______________________________ Dr. Alexis F. L. A. Powell Major Advisor ______________________________ Dr. David R. Edds Committee Member ______________________________ Dr. Lynnette Sievert Committee Member ______________________________ Dr. J. Daren Riedle Committee Member ______________________________ Dr. Tim G. Burnett Department Chair ______________________________ Dr. Jerald Spotswood Dean of the Graduate School and Distance Education ii ACKNOWLEDGMENTS I thank my advisor, Alexis Powell, and my committee—Lynnette Sievert, J. Daren Riedle, and David Edds—for their patience and guidance on this project. I could not have done this study without field assistance from Justin Autz, John Bellah, Jennifer Buchanan, Jack Holmgren, Tucker Love, and Sam Schneider. I thank Greg Sievert for assistance with turtle identification and visual surveys, Rich Sleezer for his assistance with ArcGIS, and Jennifer Rader and Eric Kessler for sharing specimens and knowledge. Most importantly, I thank my family for their constant support and assistance with anything and everything I do. Access to museum specimens was provided by Luke Welton at the University of Kansas Biodiversity Institute and Natural History Museum and by Curtis Schmidt at the Sternberg Museum of Natural History. Animals were captured and handled in accordance with collecting permits from the Kansas Department of Wildlife, Parks and Tourism (SC-098-2017, SC-027-2018; SC-030- 2019) and approval of the Emporia State University Animal Care and Use Committee (ESU- IACUC-18-004; ESU-IACUC-19-003). Funding and equipment were provided by the Friends of the Sunset Zoo, by Emporia State University through scholarships (Graduate Research Scholarship, Thesis Support Award, and New Graduate Student Scholarship) and its Department of Biological Sciences, and by the Kansas Department of Wildlife, Parks and Tourism. iii PREFACE This thesis is divided into two chapters, the first covering the status of the Northern Map Turtle (Graptemys geographica) in Kansas and the second covering geographic distributions and taxonomic limits within the False Map Turtle Complex. Both chapters were prepared following manuscript submission guidelines of Herpetological Review. iv TABLE OF CONTENTS Page ACKNOWLEDGMENTS ............................................................................................................. iii PREFACE...................................................................................................................................... iv TABLE OF CONTENTS.................................................................................................................v LIST OF TABLES........................................................................................................................ vii LIST OF FIGURES ....................................................................................................................... ix CHAPTER 1 Conservation status of the Northern Map Turtle (Graptemys geographica) in Kansas INTRODUCTION ...............................................................................................................1 MATERIALS AND METHODS.........................................................................................5 Trapping surveys......................................................................................................5 Visual surveys ..........................................................................................................6 Acquisition of additional records.............................................................................7 Stream order analysis ..............................................................................................7 Habitat modeling .....................................................................................................8 RESULTS ............................................................................................................................8 Trapping surveys......................................................................................................8 Visual surveys ........................................................................................................10 Acquisition of additional records...........................................................................12 Stream order analysis ............................................................................................13 Habitat modeling ...................................................................................................13 DISCUSSION....................................................................................................................14 v Conservation recommendations.............................................................................20 LITERATURE CITED ......................................................................................................23 APPENDIX A....................................................................................................................48 CHAPTER 2 Phenotypic variation, distributions, and taxon limits within the False Map Turtle Complex (Graptemys pseudogeographica and allies) in Kansas INTRODUCTION .............................................................................................................54 MATERIALS AND METHODS.......................................................................................56 Museum specimens.................................................................................................56 Trapping surveys....................................................................................................58 Visual surveys ........................................................................................................59 RESULTS ..........................................................................................................................59 Museum specimens.................................................................................................59 Trapping surveys....................................................................................................61 Visual surveys ........................................................................................................62 DISCUSSION....................................................................................................................62 LITERATURE CITED ......................................................................................................67 APPENDIX B ....................................................................................................................96 PERMISSION TO COPY STATEMENT...................................................................................131