Biology and Conservation of North American Tortoises
Publication Year: 2014
Published by: The Johns Hopkins University Press
Title Page, Copyright Page
List of Contributors
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Chapter 1. Morphology, Taxonomy, and Distribution of North American Tortoises: An Evolutionary Perspective
Dennis M. Bramble and J. Howard Hutchison
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Modern gopher tortoises are the remains of a once abundant and diverse North American tortoise fauna (Williams 1950a, Auffenberg 1974, Bramble 1971). The group is endemic to North America and has an especially rich fossil record. As the...
Chapter 2. The Fossil Record for North American Tortoises
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Gopher tortoises are terrestrially adapted turtles in the family Testudinidae. The modern members of these specialized tortoises are grouped into two lineages, Gopherus Rafinesque 1832 and Xerobates Agassiz 1857. They are represented by the following living species, one in the Southeast...
Chapter 3: Systematics of Extant North American Tortoises
Robert W. Murphy
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Systematics concerns the phylogeny and taxonomy of species, and usually the drivers of their evolution. The field spans from microevolutionary relationships, typically maternal genealogies, to macroevolutionary, interspecific...
Chapter 4. Thermoregulation and Energetics of North American Tortoises
James R. Spotila, Thomas A. Radzio, and Michael P. O'Connor
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The basic thermal biology of tortoises has been known for more than 120 years. Hubbard (1893) described the summer foraging of Gopherus polyphemus in Florida and noted that they emerged in midday between 1100 and...
Chapter 5. Reproductive Physiology of North American Tortoises
David C. Rostal
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The reproductive biology of each of North America’s tortoises has been studied at least to some degree in all five species. Gopherus agassizii and G. polyphemus have received the most attention from researchers, and these...
Chapter 6. Embryonic Development, Hatching Success, and Temperature-Dependent Sex Determination in North American Tortoises
David C. Rostal and Thane Wibbels
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A variety of reptiles possess temperature-dependent sex determination (TSD) (reviewed by Janzen and Paukstis 1991, Janzen and Krenz 2004), including many endangered and threatened species. TSD is of significance in the...
Chapter 7. Growth Patterns of North American Tortoises
Henry R. Mushinsky
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The rate of growth of an individual tortoise affects the time it takes to achieve the minimum size for sexual maturity, and therefore has a significant influence on the number of offspring an individual can produce in its...
Chapter 8. Health Issues of North American Tortoises
Elliott R. Jacobson
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In many areas within their ranges, North American tortoises (Gopherus polyphemus, G. berlandieri, G. agassizii, G. moraf kai, and G. flavomarginatus) are in decline. Causes for decline include increased predation by domestic and...
Chapter 9. Habitat Characteristics of North American Tortoises
Kenneth E. Nussear and Tracey D. Tuberville
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North American tortoises are distributed in semiarid and temperate deserts and coastal regions of the southern United States and Mexico (Bury and Germano 1994). The five species currently recognized each have...
Chapter 10. Water and Food Acquisition and Their Consequences for Life History and Metabolism of North American Tortoises
Todd C. Esque, K. Kristina Drake, and Kenneth E. Nussear
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Acquisition of sufficient food and water and the physiological consequences that occur when resource availability fluctuates are key to understanding the maintenance (Peterson 1996a, b), growth (Medica et al. 2012)...
Chapter 11. Home Range and Movements of North American Tortoises
Joan E. Berish and Philip A. Medica
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Home range and movements of North American tortoises are influenced in both dramatic and subtle ways by climatic factors, topographical features, burrowing substrate, forage availability, social interactions...
Chapter 12. Social Behaviors of North American Tortoises
Craig Guyer, Sharon M. Hermann, and Valerie M. Johnson
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Tortoises are thought to have inhabited North America for 50 million years (Le et al. 2006) and the genus Gopherus has been around for at least 30 million of those years (Bramble 1974; chapters 1 and 2). Although assemblages...
Chapter 13. Nesting and Reproductive Output among North American Tortoises
Roy C. Averill-Murray, Linda J. Allison, and Lora L. Smith
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Information on reproduction is highly variable among the five species of North American tortoises. Few quantitative data from wild populations exist for Gopherus flavomarginatus and none from Mexican populations of G. morafkai, while...
Chapter 14. Abundance of North American Tortoises
Linda J. Allison and Earl D. McCoy
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A species’ commonness in an area can be described in several ways. Abundance is one quantity of interest, as is the density of individuals, which is abundance per unit area, and is useful as a currency for comparing areas...
Chapter 15. Population and Conservation Genetics of North American Tortoises
Taylor Edwards and J. Scott Harrison
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One of the principal goals of conservation is to preserve the diversity of species. Integral to achieving this goal is the conservation of genetic, ecological, and morphological variation within a species and among populations...
Chapter 16. Demography of North American Tortoises
Earl D. McCoy, Gustavo Aguirre L., Richard T. Kazmaier, and C. Richard Tracy
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Life-history traits include those characters ultimately influencing the growth and persistence of populations in the face of environmental change. In general, the traits of males, as well as the sex ratios of populations, may not be...
Chapter 17. History of Human Interaction with North American Tortoises
Michael Tuma and Craig B. Stanford
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North American Gopherus tortoises have a 35 million-year history on the continent (Auffenberg 1974; chapter 2). They have lived alongside human populations for a tiny fraction of their evolutionary history. But an...
Chapter 18. Threats and Conservation Needs for North American Tortoises
Kristin H. Berry and Matthew J. Aresco
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Since the 1500s, at least ten species of tortoises and freshwater turtles have become extinct (Turtle Conservation Coalition 2011), and many more are critically endangered with extinction. All five extant species of Gopherus face...
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Page Count: 208
Illustrations: 19 halftones, 30 line drawings
Publication Year: 2014