One can often recognize the maturation of a discrete field of research when two events occur, the inception of a specialty journal and the publication of a field-specific textbook. Arguably, the field of conservation genetics was born with the publication of Conservation and Evolution (Frankel and Soulé 1981, also published by Cambridge University Press), but it would take nearly 20 years before the journal Conservation Genetics was first published in 2000. This was soon followed by the publication of an introductory textbook. The authors of Introduction to Conservation Genetics are conservation biology heavyweights who bring a unique mix of perspectives to this book. Richard Frankham is professor of biology at Macquarie University, Sydney, Australia; his expertise is wide-ranging and includes quantitative genetics, estimation of genetically effective population size, and the relationship between quantitative variation, variability in neutral markers, and their relative significance in conservation genetics. Jon Ballou is population manager at the National Zoological Park, Smithsonian Institution, Washington, DC, and adjunct at the University of Maryland. As such, his expertise lies in the area of small population management. David Briscoe is associate professor of Biology at Macquarie University and has collaborated with Frankham on a number of projects, including the use of Drosophila to test conservation genetic hypotheses under laboratory conditions.
This textbook is intended to introduce advanced undergraduate and graduate students to the field of conservation genetics; it is also intended for professionals wishing to augment their knowledge in this area. The authors have compiled a set of concrete examples that could be used by instructors in population genetics and evolution courses to “enthuse their students.” Details on experimental design and laboratory procedures are deliberately omitted so as to concentrate on general principles. A working knowledge of Mendelian genetics and elementary statistics is assumed.
The text begins by introducing the reader to conservation genetics as a distinct discipline, to the need for and utility of conservation genetics given our current extinction spasm, and to themes that are recurrent throughout the book. The second chapter addresses the direct connection between species persistence and genetic variability. It is important to explicitly address this issue because the argument has been made (e.g., Lande 1988) that demographic events lead to species extinctions long before a lack of genetic variability can become important to species persistence. Three sections follow. Section I (seven chapters) contains a short course in population genetics. Population genetic theory generally addresses evolutionary changes within large populations. One reviewer of this book (Smith 2002) suggested that the introductory material in Section I was geared too heavily toward uninformed readers. I think that the inclusion of basic concepts of population genetics is appropriate in a textbook intended for a wide audience of advanced undergraduates, graduate students, and management professionals. At worst, much of this section could be skipped over or assigned as additional reading in advanced conservation genetics courses. Turning the argument around, section I could serve as the basis for a brief introduction to population genetics in courses such as evolution or population genetics.
Section II contains five chapters dealing with the population genetic consequences of small population size. The effects of small population size on genetic variability and population persistence are what set conservation genetics apart from the larger fields of evolutionary and population genetics. Small population size is the common thread that defines species of conservation concern despite a large diversity of life histories and ecologies among them. Inbreeding and its effects on population persistence are discussed in two chapters within section II and provide follow-up to the discussion begun in chapter 2. Although some might find this approach repetitive (Hedrick 2002), inbreeding and the inbreeding-like effects of drift (discussed in a different chapter in section II) are at the heart of the argument for maintaining genetic diversity in endangered species. Inbreeding provides a direct link between population genetics and population persistence.
Section III (six chapters) is perhaps the most interesting from my perspective as a conservation geneticist who has worked with a number of species of conservation concern. This section is replete with examples and discusses applications of population genetics theory to conservation problems. It is in this realm that conservation genetics can be truly distinguished from the fields of population and evolutionary genetics, which provide its theoretical underpinnings. Chapters on genetic management of wild populations, genetic management of captive populations, and the genetics of reintroductions are included in this final section.
Frankham and his colleagues have done a good job of providing the extras that make for a user-friendly textbook. Features include an opening précis for each chapter and a list of important terms. Chapters are divided into logically ordered sections, and marginal text boxes highlight the important points in each section. Many of the data figures (graphs and tables) are accompanied by well-done ink drawings of the relevant organism. A few black-and-white photographs also accompany the text. Highlighted text boxes are used to set aside in-depth consideration of specific examples. Each chapter is provided with a summary and an annotated list of further reading that usually includes review articles on the chapter topic. Finally, each chapter ends with a problem set, and many have a set of practical exercises as well. Most of these problems are quantitative and appear ideal for take-home assignments. Although at first glance the practical exercises do not appear all that useful from an instructor's point of view, it should be noted that most of the resources needed to do the exercises (e.g., simulation programs and data files) are available for downloading from a Web site that is maintained in conjunction with the book ( http://consgen.mq.edu.au). At the end of the book are 17 “take-home messages” intended to provide a concise summary of the important themes in the book. When combined with the chapter-opening main points and marginal text boxes, these messages may provide those more befuddled students with a starting point for understanding the more central concepts. A 12-page glossary follows the messages. The reference section is extensive, spanning 39 pages, and most of the references are quite recent (many were published within the last two or three years).
Despite the length of the text, the writing style remains succinct and crisp throughout. Furthermore, the style is very clinical in the sense that the authors assume that the reader is already concerned about the loss of all forms of biodiversity and does not have to be told about this aspect of the problem. While some conservation biologists advocate a more activist role for researchers in all aspects of the field (e.g., Noss 1996), Frankham and colleagues take what is, in my opinion, the appropriate approach by confining their discussion to empirical results without overt emotional appeals.
This book is a very welcome addition to my library. As an instructor in undergraduate and graduate evolution, population genetics, and conservation genetics courses, I found it unfortunate that no synthetic treatment of conservation genetics was available as a class textbook. As a result, I depended on population genetics texts (Hartl and Clark 1997) and compilations of case studies (e.g., Soulé 1986, Avise and Hamrick 1996). Although adequate for the task, these works were not really designed for use in undergraduate instruction. I am looking forward to teaching conservation genetics from this text. Its strengths lie in the thorough discussion of quantitative genetics and the chapters dealing with genetic management of captive and reintroduced populations. Above all, we finally have a text that does a good job of integrating population and evolutionary genetic theory with real-world conservation genetic examples and applications.