Biodiversity of Fungi: Inventory and Monitoring Methods. Gregory M. Mueller, Gerald F. Bills, and Mercedes S. Foster, eds. Elsevier Academic Press, Burlington, MA, 2004. 777 pp., illus. $99.95 (ISBN: 0125095511 cloth).
Imagine trying to document the diversity of the world's fungi. You would have to look literally everywhere—from the microscopic fungi that parasitize the protozoa in animal rumens to the lichens that colonize the leaves of the highest trees. After you finished looking on and inside all of Earth's plants and animals, you could begin sampling soil, fresh water, estuaries, and oceans. It would be an immense task, but luckily you now have a guide: a one-stop reference book called Biodiversity of Fungi: Inventory and Monitoring Methods. This volume illustrates the enormous amount of work it would take to document fungal diversity, while simultaneously breaking the task into more manageable chunks.
Biodiversity of Fungi argues that fungi and their allies (slime molds and water molds) are critically important players in the world's ecosystems, yet science has documented relatively few of the species that are thought to exist. The book's purpose is to provide standardized methods for quantitative measures of fungal populations in almost any habitat. Perhaps equally important, the book encourages researchers not only to carefully record their discoveries—with annotated voucher specimens deposited in herbaria—but also to create computerized databases in a form that others can share. After all, they argue, no one benefits from poorly documented or inaccessible research.
Not surprisingly, Biodiversity of Fungi is a team effort, requiring three editors and about 10 years of work. Two of the editors have extensive experience in mycology. Gregory M. Mueller is curator of mycology and chair of botany at the Field Museum of Natural History in Chicago; Gerald F. Bills studies the systematics, diversity, life history, and ecology of filamentous fungi at Merck Research Laboratories. Mercedes S. Foster, of the US Geological Survey's Patuxent Wildlife Research Center at the Smithsonian Institution's National Museum of Natural History, has previously edited books on measuring and monitoring the biodiversity of mammals and amphibians. Together, the three editors coordinated the efforts of some 88 expert authors.
The book's content is divided into three units. Unit I consists of six chapters that cover general issues relevant to all fungal research. Serious researchers should take special note of the chapters on herbaria, database design, and statistical considerations. The 20 chapters of unit II, which occupy the bulk of the book, describe detection and isolation techniques. Unit III is a collection of useful resources, including recipes for culture media; lists of institutions, Web sites, and vendors; and a glossary.
Unit II is organized mostly by habitat. Chapters include guidelines for finding fungi on or in other fungi, living plants (both inside and out, for both shoots and roots), plant debris, wood, soil, arthropods and other invertebrates (both terrestrial and aquatic), vertebrates (both inside and out), dung, fresh water, estuaries, and oceans. Even “stressful” environments—those that are hot, cold, nutrient poor, salty, dry, or metal contaminated—are included. A few chapters depart from this habitat-based focus and instead discuss fungi by group, including lichens, sequestrate fungi, yeasts, and slime molds. Along the way, the book acknowledges the many difficulties that researchers face when inventorying fungi: the huge number of undescribed species, the ubiquity of fungi nearly everywhere on Earth (with scores of species colonizing the same tiny substrate), multiple correct binomial names for different stages in the same organism's life history, constantly changing names, and species that refuse to grow in pure culture.
Because it is so wide-ranging, this book will be useful for both beginners and experts. Many chapters are extremely user-friendly, giving easy-to-follow instructions for collecting fungi, preserving cultures, and keeping records. However, beginners may find other chapters difficult. For example, the first chapter introduces the current state of systematics for the fungi and their allies. It dives right into terminology such as dolipore septa, plesiomorphies, and homoplasies. A cladogram accompanies the discussion of each phylum, but this introductory chapter would have been more useful to beginners if illustrations of zygospores, asci, basidia, and other fundamental features of the fungi were included. Likewise, the unit I chapter on quantitative measures of species diversity was hard for me to follow. Without extensive training in this area, I found it hard to tell how the subtopics related to each other. Thankfully, the authors included several helpful summary tables, and the chapter is useful because it brings relevant references together in one place.
My favorite parts of the book were those that directly supported its mission to guide researchers in finding fungi. I enjoyed reading the parts that explained how to select sampling locations, how big the plots should be, where to look for fungi, what information to collect in the field, how much time to expect to spend in the field and in the lab, and how to store specimens and data. One chapter has wonderful examples of data sheets; another has an appendix that suggests the size, type, and format of fields one could incorporate into a computerized database. I also liked the practical discussions showing how statistical and logistical constraints make it difficult to calculate species richness in certain habitats.
The book has many other useful features as well. Most chapters contain at least one table. Especially useful are those that list some typical genera, organized by phylum, class, and order. Two chapters even include keys to genera. The 40-page, illustrated glossary was also helpful. As I read the book, I tested the glossary by looking up several words that I assumed a beginning reader would not know. Most were in the glossary, and many entries had simple line drawings that helped illustrate the concept.
Biodiversity of Fungi does have some shortcomings. A minor complaint is that some topics occur in odd places. For example, chapter 21 describes the life cycles of major groups of fungi and their allies, along with useful definitions of the specialized terminology in dichotomous keys. This information would have been better placed in the first chapter, where it could help nonspecialists decipher some basic fungal biology and vocabulary. Similarly, surface sterilization is described in the chapter on endophytic fungi, even though these techniques would also be useful for researchers who might want to “bait” for fungi in many habitats. The appendix would have been a more suitable place for this topic.
A more significant problem is that the chapters do not follow a standardized outline, so the contents vary widely from chapter to chapter. For example, some chapters have as many as 12 sections, while others have as few as 3; and the section titles are inconsistent from chapter to chapter. Some chapters include advice on designing sampling schemes or fixing material for DNA analysis; others do not. Some emphasize background over technique; others do the opposite. Some chapters include conclusions or recommendations for future research; others do not.
This nonstandardized approach means that each chapter discusses the issues that are most relevant to each habitat type, but it also leads to uneven coverage. The chapter on yeasts, for example, is just six pages long, with no illustrations and sparse detail on where to find yeasts, what features to look for, or diversity. The next chapter, which describes fungi that eat other fungi, totals 50 pages and illustrates the other extreme. It includes extensive detail on group-specific terminology, taxonomic groups (illustrated by color photos), distribution, identification, research methods, examples of fungi that colonize five different subgroups of fungi, and a description of the use of fungi as biological control agents.
The preface seems to acknowledge this lack of uniformity: “It will become apparent to the user…that the state of knowledge regarding fungal sampling is uneven from habitat to habitat and taxon to taxon and that few quantitative procedures have been developed”(pp. xi–xii). Even so, a uniform outline would have helped to highlight these gaps—and perhaps to guide future research—instead of obscuring them in a mix of different formats.
Just as the content coverage is uneven, so are the illustrations. Many chapters (notably those on fungi that eat other fungi, rotifers, and nematodes) have excellent art and abundant, beautiful, large photos. Other chapters, however, lack illustrations altogether. The chapters on voucher specimens, culture preservation, yeasts, and chytrids would be more useful if the procedures and important structures were not left to the reader's imagination.
Even with these limitations, Biodiversity of Fungi is a welcome addition to my reference bookshelf. I have often wished for a book that combined fungal sampling methods in one place, and I am grateful that this enormous team of editors and authors has completed this heroic undertaking. As a bonus, the book makes a strong case for the importance of systematically cataloging and quantifying fungal diversity. Realistically, science may never be able to complete the task of inventorying all of the world's fungi, slime molds, and water molds; but with this book, we can at least take a shot at it.