Ex Situ Plant Conservation. Supporting Species Survival in the Wild. Guerrant, E. O. Jr., K. Havens, and M. Maunder, editors. 2004. Island Press, Washington, D.C. 504 pp. $80.00 (hardback). ISBN 1-55963-874-5. $40.00 (paperback). ISBN 1-55963-875-3.
Ex Situ Plant Conservation focuses on how we can most effectively store genetic samples and then germinate and propagate them with the primary purpose of preserving species in the wild. Cutting right to the bottom line, this book is an important contribution to the field of plant conservation. It will help conservationists save plants from extinction and improve the success of our restoration efforts. This book is a “must have” for managers, scientists, and researchers involved in plant conservation.
Both the editors and chapter authors are well aware of the controversies that swirl around ex situ efforts and the reluctance of some to engage in ex situ efforts because they fear that these efforts will compromise in situ conservation. Consequently, not only is an entire chapter devoted to this topic but almost every author stresses that the primary, if not sole, purpose of ex situ conservation is to facilitate in situ conservation. This treatment successfully drives home the argument that ex situ conservation is a means to an end, not an end in itself.
The book has four parts that address why we use ex situ techniques, what those techniques are, how to mitigate associated problems, and finally how to most effectively use these techniques. “Part I, The Scope and Potential of Ex Situ Plant Conservation,” when considered together with Peter Raven's foreword and Ghillean Prance's introduction, accomplishes two key tasks. First, it explains why ex situ conservation is an important component of integrated conservation. As might be expected, this is primarily done by discussing the magnitude of the extinction crisis facing the world's floras, and by providing examples of how ex situ efforts have been successful. Although this may be old hat to conservation biologists, the discussions, especially Raven's foreword, are important to set the stage for the rest of the book. Anne Cochrane's chapter on western Australia's ex situ program shows how ex situ efforts and research can be integrated with in situ strategies into a sound, effective conservation program, even in an area with thousands of at-risk species. Cochrane's is a particularly interesting chapter because it goes beyond theoretical suggestions and shows what can actually be accomplished.
Second, several chapters in Part I cover the shortcomings of current efforts and challenge us to do better. The closing chapter in this part (Price et al.) explores how zoos and aquaria have addressed ex situ conservation. Their essay is an informative discussion of how botanical gardens might be able to do more in the ex situ realm and in the areas of research, partnering between facilities in developed and developing countries, and financial support for in situ conservation.
“Part II, Tools of the Trade,” is just that—an explanation of ex situ techniques. These chapters make good introductions to germ-plasm storage, dormancy and germination, tissue culture, and pollen storage. Pence's chapter is devoted to ex situ methods for bryophytes and ferns—an often-overlooked group of plants. Walters and Pritchard's chapters give an overview of the science behind recommended procedures for determining seed types (orthodox, intermediate, and recalcitrant) and appropriate storage options. The chapter on dormancy breaking by Carol and Jerry Baskin contains clear and useful discussions on dormancy types and germination strategies. Several of these chapters are right on target in that they translate years of experience and extensive knowledge into easily understood, practical discussions.
“Part III, The Ecological and Evolutionary Context of Ex Situ Plant Conservation,” is really a series of discussions on problem areas in ex situ conservation. These chapters discuss hybridization in living ex situ collections, the erosion of germ plasm in storage, the loss of plants during reintroduction efforts, population genetics issues, unintended selection imposed by ex situ environments, and the effects of seed collection on wild populations. All these chapters are interesting and important, with several significantly advancing the science of ex situ conservation. The chapters on how populations respond to ex situ conditions (Husband and Campbell) and how seed collection may affect the extinction risk of wild populations (Menges et al.) are particularly thought provoking.
The final section, “Part IV, Using Ex Situ Methods Most Effectively,” summarizes the preceding chapters. The summary chapter focuses on big-picture issues related to conservation priorities and infrastructure and leaves the technical summaries to the appendices, which present guidelines of interest to ex situ plant conservation. It is these appendices that will be of most use to ex situ practitioners. Appendix 1, “Revised Genetic Sampling Guidelines for Conservation Collections of Rare Plants,” is a significant update to the original guidelines in Falk and Holsinger (1991). These guidelines incorporate new and important information from earlier chapters. Although Appendix 2, “Guidelines for Seed Storage,” offers good guidance on how to store orthodox seeds, it would benefit from additional information on cryopreservation options for recalcitrant seeds. Appendix 3, “Guidelines for Ex Situ Conservation Collection Management: Minimizing Risks,” is where most of the new information in the book is summarized and where recommendations are presented. Appendix 4, “Conservation Organizations and Networks,” illustrates the type and range of organizations undertaking ex situ plant conservation.
This book is part of a series, The Science and Practice of Ecological Restoration, from the Society for Ecological Restoration International. It is also the third volume from the Center for Plant Conservation that addresses the science of ex situ plant conservation. Earlier books include the Genetics and Conservation of Rare Plants (Falk & Holsinger 1991) and Restoring Diversity: Strategies for the Reintroduction of Endangered Plants (Falk et al. 1996). Taken together, these three books offer detailed guidelines for the collection of genetic samples, the maintenance of those collections (the current book), and the reintroduction of species. Although the trilogy might now be complete, there may be room for a volume that fully integrates ex situ and in situ plant conservation.
The editors and chapter authors of Ex Situ Plant Conservation have assembled a book that significantly advances the science. It will be highly useful to those who actually do ex situ plant conservation, and it will also better inform others of the role that ex situ efforts can play. The most important contributions of this book are that it (1) summarizes the current state of knowledge for most plant ex situ techniques; (2) specifically tries to solve historically contentious problems with new analyses; and (3) contains three highly useful sets of guidelines on genetic sampling, seed storage, and collection management. A number of the chapters represent new analyses and new thinking. Despite a good effort to summarize recommendations in the final chapter, there are many information “gems” that remain hidden throughout the individual chapters. A critical, thorough reading of the individual chapters and appendices will better challenge and inform the reader than simply going to the summary chapter. In addition, there are topical areas that are underaddressed (i.e., the role of ex situ collections in research) or are inconsistently addressed (i.e., the value of cryopreservation for recalcitrant seeds). Yet these issues are easily overlooked when one considers the overall importance of the volume.