Food Web of a Tropical Rain Forest, The

The Food Web of a Tropical Rain Forest. DOUGLAS B. REAGAN AND ROBERT B. WAIDE, eds. University of Chicago Press, 1996, xi + 616 pp. paper ISBN: 0-226-70600- 1.

Food web studies have had a long and glorious run in ecological studies. The verbal descriptions of who eats whom in early naturalists' accounts have enchanted generations of readers. Visual representations of food webs date from as far back as Summerhayes and Elton in 1923. From the 1980's onward there have been several books on Food Web theory and practice, culminating in a major synthesis of food webs in a volume edited by Polis and Winemiller in 1995. This book made a significant advance by explicitly considering organic detritus and the organisms active in this usually preponderant part of the net primary production as it is processed by organisms in an ecosystem. The microbial and many faunal consumers of the microbes, or the microbe-laden debris, lead to manifold and very long food chains, which are generally cryptic but fascinating links in food webs.

The book by Reagan and Waide draws upon the current wave of popularity in food webs, but also is a primary beneficiary of an earlier classic, "A Tropical Rain Forest," (H. T. Odum and R. F Pigeon, eds., 1970). Having been a minor but enthusiastic participant in the Odum project, it is interesting for this reviewer to see what areas of inquiry have been emphasized in the Reagan and Waide tome, and what aspects have not. The Odum volume centered upon the preand post-treatment effects of massive doses of gamma radiation applied in radii extending out to ca. 120 meters, and a "control center" nearby served as an appropriate contrast. The overall mission was to calculate "a degree of predictability as to bioenvironmental costs," which would serve as a surrogate for future environmental impacts on such a site.

The identical 40 ha. study area at El Verde, in Northeastern Puerto Rico covered earlier in the Odum volume, has been addressed in terms of trophic interactions a quarter-century later, supported in part by the Long-term Ecological Research (LTER) program of the National Science Foundation. The new Food Web book examines the effect of a natural disturbance, namely the very high hurricane-force winds of Hurricane Hugo in September 1989, to set trophic interactions across time-spans of several years into a more qualitative context of who eats whom, when, and where in the entire rain forest ecosystem. The Reagan and Waide volume draws heavily upon the base-line data generated through much of the 1960s by literally dozens of collaborators in the Odum volume, several of whom are also contributors to the current tome. The chapters include 3 initial ones, The Rain Forest Setting (Waide and Reagan), Plants: the Food Base (Lawrence), and Microorganisms (Lodge), which is then followed by four chapters on invertebrates, by McMahan on termites, Pfeiffer on litter invertebrates, Garrison and Willig on arboreal invertebrates, and Pfeiffer on arachnids. Five chapters follow on vertebrates: amphibians by Stewart and Woolbright, anoline lizards by Reagan, nonanoline reptiles by Thomas and Kessler, birds by Waide, and mammals by Willig and Gannon. The stream community is nicely covered by Covich and McDowell, and the final summary and synthesis, entitled: "The community food web: major properties and patterns of organization" is by Reagan, Camilo, and Waide.

A number of features about the El Verde Food Web are noteworthy: Anyone who has been to piedmont or montane Puerto Rico knows that the tree frogs, or "coquis," are ubiquitous and very abundant. This is true for a numerous amphibian fauna in general. Anoles and other lizards are also plentiful.. Large mammalian herbivores and predators are absent. Total vertebrates, 78, are a small fraction of the >420 on Barro Colorado Island, and even lower proportionally compared to other mainland wet tropical sites. Interestingly, the number of soil microarthropod species in any patch of forest floor at El Verde is only 20-30% less speciose than a comparable patch at La Selva, Costa Rica (L. J. Heneghan, pers. comm.). The book isn't encyclopedic, as microfauna such as protozoa and nematodes weren't included. Other findings in the final synthesis are noteworthy: within the aggregated El Verde food web, there are a total of 19,804 food chains, with a mean chain length of 8.5, SD = 3.2. This long chain length accords well with earlier detailed studies of Polis in the Coachella Valley desert, and even detrital food web studies in Europe and the USA. As in several other recent food web studies, omnivory is not the exception, but really the norm.

There is a wealth of interesting detailed life-history and theoretical studies comparison in this book. It certainly makes one eager to get into the field to test some of its ideas and findings in other sites during the next several years. The entire volume is well-organized, virtually error-free, and well worth acquiring by any ecological practitioner, including faculty and graduate students alike.