Invertebrate Conservation and Agricultural Ecosystems

T. R. New
Cambridge University Press
Cambridge, UK, 2005, 348 pp.
hardback, $120.00, paperback, $60.00
ISBN: 0-521-82503-2 (hardback); 0-521-53201-9 (paperback)

As expected from the title, conservation biology meets agricultural management in Invertebrate Conservation and Agricultural Ecosystems. The book makes the case that reserves and other protected areas are inadequate for invertebrate conservation, and therefore, future efforts to effectively enhance biodiversity must be expanded to include the entire landscape. Moreover, because agroecosystems are major components of the interreserve landscape matrix, they are especially critical to invertebrate conservation. This demands a reconsideration of agricultural management practices, particularly those pertaining to pest management, so that, with some modification, they help foster a more holistic, landscape perspective that is favorable to conservation. In short, "[w]hat happens in agroecosystems, and the ways in which they are managed, affects the environment and biota in much … of the landscape" (p. 17).

The book is divided into 10 chapters that cover 311 pages of text, with an additional 37 pages of up-to-date references to support facts and examples. The first three chapters present the issues involving conservation and agriculture and also cover relevant ecological concepts. The remaining chapters discuss ways in which specific pest- and landscape-management practices impact invertebrate biodiversity.

Chapter 1 sets the stage for concepts and issues discussed throughout the rest of the book. It begins by outlining the features of agricultural systems and compares and contrasts agroecosystems versus natural ecosystems. Chapter 1 points out the limitations of confining the thrust of conservation efforts to reserves or natural areas, and cogently makes the case that sound management of agricultural landscapes is crucial for advancing invertebrate conservation.

The second chapter highlights the functional diversity of invertebrates in agroecosystems, discusses the taxonomic challenges of accurately estimating biodiversity, and emphasizes the dominant roles of Annelida, Mollusca, Nematoda, and Arthropoda in the ecological maintenance of agroecosystems. Despite the attention to other groups here, the remainder of the book focuses mainly on issues involving arthropods.

The first part of Chapter 3 provides a general outline of the threats to invertebrates from agriculture and could have served as a springboard into later chapters on specific management practices. However, the second part of Chapter 3 largely discusses how to capitalize on the use of invertebrates as indicators of environmental health, and in doing so, revisits some practical and taxonomic challenges of working with invertebrates that were raised in Chapter 2.

The fourth chapter, with 53 pages, is the longest one in the book. The first 19 pages effectively cover additional concepts directly applicable to agroecosystems such as disturbance and the r-K continuum of ecological strategies and provide ecological underpinnings for definitions of terms such as pest, economic injury level (EIL), economic threshold, pest control, and integrated pest management (IPM). This part of Chapter 4 is transitional, with many references to earlier and future chapters. The remaining 34 pages of the chapter are devoted to concepts and concerns about pesticides and ways to evaluate and minimize their impact on invertebrates. The first part of Chapter 4 could have stood alone or its contents could have been integrated into the first three chapters, whereas the part on pesticides could have been split off to form the first in the series of latter chapters on specific management approaches.

One major theme of the book is biological control, and various aspects of this topic are presented in portions of four chapters. Chapter 5 reviews the concepts of classical biological control (BC) and its impact on invertebrate conservation. This chapter efficiently presents the issues related to classical BC, single versus multiple species introductions, neoclassical BC, etc., and is chock-full of examples that document and appraise the risks and impact of BC.

Conservation BC is discussed as a component of cultural pest management in Chapters 6-8. The first section of Chapter 6 provides a conceptual overview of cultural pest management in relation to invertebrate conservation, and the last section discusses the nature and impact of specific cultural practices such as intercropping, trap cropping, tillage, and planting density. The next chapter extends the discussion of cultural management and conservation BC beyond cropping areas to field margins, and Chapter 8 expands these themes even further into wider contexts involving the ecology of landscape matrices and metapopulations. Chapter 9, with only 11 pages, is a digression on management practices (e.g., grazing and mowing) largely relevant to pastoral landscapes.

Chapter 10 resumes with the landscape management theme from Chapter 8 and includes cursory discussion about the implications for invertebrate conservation in regard to areawide pest management (<2 pages), prescriptive land management (<3 pages), and biotechnology (<4 pages). Even though there is roughly another page of discussion on genetically modified plants earlier in the book (pp. 186-187), these three topics deserve much more discussion with respect to their potentially wide-ranging impacts on invertebrate biodiversity. Each of these issues could have justified entire chapters and should have at least generated larger sections within Chapter 10.

Invertebrate Conservation and Agricultural Ecosystems is generally well written. The chapters have lots of bulleted text, all but one have several figures, and they each contain from 1 to 11 tables. These generally highlight and clarify points in the text, but occasionally (1) bullets in the text or items within tables seem indistinct with overlapping points or categorizations and (2) tables and figures are called out two to three pages before or the page after they appear. Throughout the book, there are glitches that tell readers to see "p. 00" or "p. 000," and on p. 161, readers are told to "see p. 161" for details about the green lacewing complex. Such faults are relatively minor and do not detract appreciably from the excellent overall content of the book.

Many researchers and practitioners in the fields of ecology and pest management will find Invertebrate Conservation and Agricultural Ecosystems to be worthwhile reading. It may also be useful as a textbook in conservation biology or an advanced ecology course, as assigned reading in a graduate colloquium, and as supplemental reading for a landscape ecology class. With its numerous examples and up-to-date citations, the book makes a useful reference and deserves to be on the bookshelves of applied ecologists who are working to devise, test, and implement agricultural practices that combine sound pest management with the preservation of invertebrate biodiversity.

Louis S. Hesler
North Central Agriculture Research Laboratory
USDA-ARS
Brookings, South Dakota

Environmental Entomology
Vol. 35, No. 4, August 2006, Page 1138 - 1139