Invertebrate Conservation and Agricultural Ecosystems. T. R. New. Cambridge University Press, Cambridge, United Kingdom, 2005. 368 pp., illus. $120.00 (ISBN 0521825032 cloth).
In the first issue of Conservation Biology, E. O. Wilson described insects as “the little things that run the world.” Despite this insightful aphorism, the field of conservation biology continues to be dominated by larger animals, especially mammals and birds. However, the worm may be turning, so to speak, because appreciation of the importance of conserving invertebrates—a group that encompasses 99 percent of animal diversity and performs many vital and irreplaceable ecological functions—has grown steadily over the past two decades. Timothy New makes a major advance in educating the public and his peers on this topic in his new book, Invertebrate Conservation and Agricultural Ecosystems.
Conservation biologists have traditionally eschewed managed areas, considering them to be ecological deserts representing only the demise of more pristine natural ecosystems.
Having ridden into the breach of one of conservation biology's deeply ingrained proclivities, the predilection for fur and feathers, New takes on the other, the preference for “wild”areas over managed ones. Conservation biologists have traditionally eschewed managed areas, considering them to be ecological deserts representing only the demise of more pristine natural ecosystems. On the other hand, specialists charged with managing land for commodity production often view conservation concerns as constraints to the range of tactics that can be employed for the management of pests and other problems. This text provides the most convincing and detailed case to date that a vast amount of diversity exists and can be conserved in agricultural systems and, conversely, that pest managers can greatly benefit from the lessons learned and techniques employed by conservation biologists. Both of these groups, along with anyone else with even a tangential interest in the management of invertebrate populations, will benefit greatly from this new text.
New's background and accomplishments make him uniquely qualified to take on the ambitious scope of this book. By almost any measure, he is one of the major forces behind educating other scientists and the public in general about the conservation of insects and other invertebrates. In addition to authoring more then 20 books, including several key texts (e.g., An Introduction to Invertebrate Conservation Biology and Butterfly Conservation), New, a reader and associate professor at La Trobe University in Melbourne, Australia, has published over 350 research papers and is the editor of the Journal of Insect Conservation Biology. In recognition of New's efforts, the Royal Entomological Society awarded him the Marsh Christian Trust award for insect conservation.
The book contains 10 chapters that fall into four general categories. The first three chapters cover the basics of agro-ecology, comparisons of natural and managed ecosystems, and the importance of managed areas for conservation.
Chapter 1 provides an excellent overview of key topics in just 17 pages. Although many of these topics are reiterated or treated in greater detail later in the book, this stand-alone chapter will be widely used because of its portability. Large portions (if not the entire text) could be required in courses on conservation, but I can envision assigning this chapter in my course on pest management, too. This is the first offering I have seen that fills that void for pest-management students, who represent a large audience not often exposed to cogent material regarding conservation.
Equally impressive in this section is chapter 2, which focuses partly on the important functions that invertebrates perform, namely, the services they provide in agroecosystems. Almost by definition, the species that provide meaningful levels of services are not truly rare (although they are often in decline), so they are usually overlooked as targets for conservation. I would have liked to have seen an entire chapter devoted to this topic, but the introduction provided in chapter 2 is well done, and specific services (especially pest suppression by predators and, to a lesser extent, pollination and dung decomposition) are revisited in later chapters.
With the stage set by the first two chapters, chapters 3 and 4 provide the punch-line—a review and synopsis of the impact of agriculture on biodiversity. I found chapter 4 one of the most thought provoking because it went beyond just logically presenting accepted agroecology dogma—which is useful in itself—and took the bold step of questioning some of the field's commonly held tenets and providing counterexamples to them. Like chapter 1, the first four chapters together form a stand-alone unit, providing a solid foundation on their own and greatly enhancing the effectiveness of the later chapters.
Chapters 5 and 6 move on from the broader overviews to focus specifically on biological control, the manipulation of natural enemies (e.g., predators) to suppress pest populations.
Chapter 5 focuses on “classical” biological control involving the importation and establishment of natural enemies to control exotic pest species. The literature here is vast, and New does an admirable job of pulling it together. Whole texts have been written on this topic, but often a more concise treatment is needed, and this chapter definitely fits the bill.
Chapter 6 focuses on cultural control, the manipulation of the environment to minimize damage caused by pests through reduced rates of colonization, feeding, reproduction, or survival. The primary tactics featured are those that seek to reduce pests' survival rates by increasing the densities of natural enemies or facilitating their effectiveness. This suite of tactics, often termed “conservation biological control,”has a clear link to conservation biology, as beneficial species performing a valuable service are being conserved. The link back to “other invertebrates,” those that are not natural enemies of pests, does not appear until two chapters later, however; although it is well done, it seemed slightly disjunct. Also, it seems to imply that conservation of these other invertebrates is something that goes on outside the managed area, and I am not convinced that this is the case, since a distinct flora and therefore fauna occurs inside the field. Nonetheless, the section is comprehensive and does integrate well where it stands, so it may represent merely a deviation from my own organizational scheme.
The next two chapters deal with ecology and conservation outside the focal managed area. Chapter 7 deals with issues in areas directly adjacent to crop fields (field margins), and chapter 8 addresses issues pertaining to larger geographic areas and those farther from the field edge (landscapes). Following from the previous section, these chapters are largely concerned with conservation biological control, but other invertebrates are also addressed and complex issues involving longer-range movement, including metapopulation dynamics, are extremely well integrated here.
The final two chapters are stand-alones. Chapter 9 deals with a specific system—grasslands—and I agree that these more perennial systems are distinct enough to warrant their own chapter. It occurred to me that many parallels exist between grasslands and other nonannual systems, such as orchards and even ornamental areas (e.g., road margins). Forest areas are dealt with in the final chapter, but I feel that although they are clearly unique, there would be some synergy in integrating them here. I would (self-servingly) like to call for these other systems to be integrated into this chapter and receive the same thorough treatment in the next volume. The final chapter is eclectic but effective, and explores topics ranging from landscape structure to the implications of biotechnology. This final offering provides an appropriate capstone to a thorough and captivating text.
I will admit to having long been a fan of New's publications. I have used his texts extensively in the courses I teach and as valuable resources in my research program. This book has all the attributes that have made his others so enduringly useful. Other similar texts often fall into one of two traps: Either they provide a solid logical framework but very little connection to current literature, or they degenerate into essentially annotated bibliographies and provide very little, if any, framework. New integrates vast amounts of literature and provides a synoptic whole that is far more valuable than the sum of its parts. The reader is presented with both important, unique insights and a roadmap to the research findings on which they are based. All of this is presented with high-quality figures and tables that are particularly valuable for sharing with students because they facilitate understanding of the concepts.
I am confident that this text will be a central reference for anyone working in, or interested in, both conservation and agriculture. I hope it will captivate others with the challenges and opportunities that await them.