BOOK REVIEWS

Abstract

Ecology and Conservation of the Diamond-backed Terrapin. W. M. Roosenburg and V. S. Kennedy (Eds.). 2018. Johns Hopkins University Press. ISBN 9781421426266. 277 p. $79.95 (hardcover).—The Diamond-backed Terrapin (Malaclemys terrapin) is not a freshwater turtle, and it is not a sea turtle. Truly a one-of-a-kind, the Diamond-backed Terrapin (hereafter, terrapin) is a brackish-water species that occupies a narrow strip of habitat along the Gulf of Mexico in the southern USA and Atlantic coastlines of the eastern USA, with an isolated population on the island of Bermuda. Along with being a habitat specialist, terrapins also have a colorful history and connection to people in the United States. Historically, this species was at the center of a culinary fad of the early 1900s for terrapin soup, while it is contemporarily connected with the coastal crab fisheries, where it is commonly taken as bycatch. The editors of the book, Willem Roosenburg and Vic Kennedy, are likely two of the best to tell this unique story, and they assembled 36 subject-area experts to craft 19 chapters about the species. Roosenburg has spent his career studying many aspects of the lives of terrapins, with his focusing on the status of populations in the Chesapeake Bay (a large estuary in the mid-Atlantic region of the northeastern USA bordered by the states of Maryland and Virginia), the impact of crab fisheries on terrapins, and the role of habitat restoration on species recovery. Kennedy has been vital to understanding the historical environment of the Chesapeake Bay and its fishery. Chapter 1, Introduction and History, provides an outline to the different sections of the book and introduces the reader to interesting aspects of the biology and ecology of terrapins. The author also poses some interesting questions for the reader to consider (e.g., if terrapins naturally dispersed to Bermuda, why aren’t they in Cuba? How did terrapins become one of the few tetrapods to inhabit brackish marshes?). Following the introduction, Part 1 of the book (Chapters 2–12) focuses on the Biology and Ecology of terrapins. Chapter 2 takes the reader through the numerous ways a researcher might capture, mark, and measure terrapins, while also providing methods for those who want to study their population and reproductive biology. This chapter also introduces other methods (e.g., molecular biology, tracking methods). While I appreciate the inclusion of this chapter and the myriad of ways to capture and study the species, it was an unexpected topic to start the book given the aforementioned colorful history of the species. In fact, this great history is not shared with the reader until Chapter 13, well after all the biology of the species is discussed. This is one organizational challenge I found with the book, and I will describe others later. The next three chapters detail the Evolutionary History and Paleontological Record (Chapter 3), Taxonomy (Chapter 4), and Molecular Ecology and Phylogeography (Chapter 5) of the species. The authors make some interesting points in Chapter 3, especially the idea that the paleontological history and record of terrapins is yet to be told. Because Neogene emydids are highly understudied paleontologically, it is likely that fossil material of terrapins already exists in collections and is waiting to be identified. Chapter 4 explains the taxonomic status of this species with regard to other emydids, the historical description of the seven terrapin subspecies, and the provenance and taxonomy of the terrapins recently described in Bermuda (Davenport et al., 2005). Fossil evidence and radiometric analysis indicates that terrapins on Bermuda are a native species and were present on the island prior to human settlement (i.e., pre-dating human transport from the mainland United States; Parham et al., 2008). This chapter also describes the molecular ecology of the species (e.g., genetic differences among populations), even though the Molecular Ecology chapter (5) follows it. Because taxonomy and genetics are now intimately connected, the editors should have opted for a single integrated chapter reviewing both traditional taxonomy and modern genetics. The most important story explained by the authors in both chapters is that our understanding of terrapin taxonomy has changed dramatically over the last 50–60 years. Historically, it appears that the species was subdivided into more subspecies (seven including the nominate form) than is supported by recent molecular work, which recognizes only four genetic groupings: northeastern Atlantic, coastal mid-Atlantic, Florida, and Louisiana/ Texas (Hart et al., 2014). Although these chapters contain great information written by incredible scientists, there is considerable overlap and duplication of material. Furthermore, the authors of Chapter 5 (Molecular Ecology and Phylogeography) assume the reader is familiar with genetic techniques, acronyms, and definitions and many of these were not defined (e.g., FST, HO, Bayesian Skyline Plots), leaving this chapter less accessible to the average reader. Chapter 6 (Life History with Emphasis on Geographic Variation) is a meta-analysis of life-history traits collected throughout the terrapin’s range, specifically metrics like adult male and female body size, mean clutch size, survivorship, etc. This chapter was written like a research article, with novel information about terrapins. This contrasts with the other chapters, which were primarily reviews of specific topics. Nonetheless, the authors offer distinct conclusions regarding the variation of life-history traits along latitudinal gradients. Examples include the finding of no relationship between male or female body size and latitude (i.e., the species does not conform to Bergmann’s rule) and that females produce larger clutches of smaller eggs at higher latitudes. A key addition of this chapter was the inclusion of a Future Research Needs section, where the authors suggest interesting studies for future researchers; this section also appears in most chapters of the book. I found this refreshing because this