ELSEVIER Journal of Experimental Marine Biology and Ecology

193 (1995) 277-295

JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY

Book Reviews

Species Diversity in Ecological Communities: Historical and Geographical Perspec- tives, edited by R.E. Ricklefs & D. Schluter; University of Chicago Press, Chicago & London; 1993; 414 pp.; GBP 25.95, US$ 32.50 (paperback), GBP 78.50, US$ 98.00 (hardback); ISBN O-226-71823-9 (paperback), ISBN 0-226-71822-O (hard- back).

This book is about the spatial and temporal scales at which the mechanisms determining species diversity operate. Its genesis was a symposium organised by the editors on the “The Historical and Geographical Determinants of Community Diversity” held at the annual meeting of the Ecological Society of America in Snowbird, Utah, in August 1990. But it is not a conference proceedings. Although several chapter authors contributed to the symposium, additional authors have been selected to provide a broad coverage and a diversity of opinion. Indeed, the author-list reads like a “Who’s Who” of the most eminent and active theoretically inclined ecologists of the day, and each has given of their best. The editors hope that the book will reach an audience both of researchers actively concerned with diversity issues, and graduate students. Since I am reviewing this book for JEMBE, my primary concern is its relevance to those researchers and students concerned with marine diversity.

The book’s starting point is the lamentation that ecological studies over the last 30 years have been preoccupied with the notion that interactions among popula- tions within small areas fundamentally regulate community structure, but that this paradigm has failed to explain global patterns of biodiversity; larger scale processes (regional and historical) must also be at work, or even dominate. In addition to chapters providing generalised theoretical perspectives, the book also aims to present case studies of various regions and taxa, although it has to be said that 13 of these chapters are specifically terrestrial, and only three marine (with one freshwater). This terrestrial bias might even be misleading to the marine ecology student. In the introductory Chapter 1, we read “Within most groups of organisms, the average number of species in a sampling area of a given size reaches its maximum in tropical latitudes and decreases both northward and southward towards the poles” and “the number of species tends to increase with island size and to decrease with distance from sources of colonists”. Both global and regional patterns of marine biodiversity should not be expected to conform to

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278 Book Reviews I J. Exp. Mar. Biol. Ecol. lY_? (IYY5) 277-2Y.5

the terrestrial situation, because the spectrum of environmental variation has a longer wavelength over both ecological and evolutionary time scales than on land, and barriers to dispersal may be weaker because of the unitary nature of the seas and the planktonic dispersal mechanisms of much of the biota. For most groups of marine organisms the evidence for a latitudinal diversity cline is not compelling (Clarke, 1992); marine mammals for example reach maximum diversity in polar regions, and seaweeds in temperate latitudes. We do not know the degree to which island biogeography theory is applicable to coastal marine organisms. The mechanisms by which marine organisms maintain diversity, especially on a local scale, are also likely to differ from the terrestrial situation. For example, the concept of “keystone” species seems to be much more strongly developed in the marine context. Thus, although the 13 chapters which discuss general issues rather than case studies address many relevant questions and ideas (such as food-web theory), marine ecologists should be cautious about accepting terrestrial paradigms.

The book is arranged in four parts: 1, Local Patterns and Processes; 2, Coexistence at the Mesoscale; 3, Regional Perspectives; and 4, Historical and Phylogenetic Perspectives. Each set of Chapters is preceded by a very valuable summary and synthesis of them, identifying areas of current ignorance and suggesting priorities for future research.

Part 1 concerns local processes that constrain local species diversity, covering such topics as the processes affecting the stable coexistence of competitors. The major theme of this section, however, is the relationship observed between species diversity and productivity. Within a region this relationship is usually hump- shaped, with maximum diversity occurring at intermediate levels of productivity, and various explanations are offered. Part 2 explores how regional processes affect local diversity, and the concept of a “metacommunity” (a cluster of local communities connected by dispersal) is developed. Part 3 comprises a series of case studies (again mainly terrestrial) in which geographical comparisons, mostly between different continents, are used to evaluate the influence of local and regional processes on diversity. Clearly differences in diversity between regions, despite their environmental similarity, suggest the role of mesoscale and historical factors rather than local processes. The historical component of local diversity discussed in Part 4 is approached through studies of the fossil record, of systematics and of phylogenetics.

The concluding chapter, by the editors, is a summing up of the whole book. It discusses some of the major issues and suggests questions and approaches for the future. The final recommendations transcend the terrestrial/marine divide: “We advocate systematic comparisons of diversity between continents or ocean basins within carefully matched habitats and with multiscale sampling (my italics), in order to assess regional and local components of diversity”. “Second, alpha and beta diversity appear to vary in direct proportion to regional diversity. The generality of this relationship should be strengthened by the types of studies advocated above”. “Third, ecologists should use historical, biogeographical and systematic (including molecular) data to reconstruct the development of species

Book Reviews I J. Exp. Mar. Biol. Ecol. 193 (1995) 277-295 279

assemblages “. “Fourth, ecologists must take a more active role in investigating the process of species production and extinction”. “ Finally, ecologists should join with physiologists, functional morphologists, and evolutionists in studying adaptive radiation and entry into new adaptive zones”. Who could not agree.

This is a dense book which marine ecologists are not likely to read from cover to cover. But dipping in will provide them with plenty of food for thought.

Reference

Clarke, A., 1992. Is there a latitudinal diversity cline in the sea? Trends Ecol. Evol.,Vol. 7, pp. 286-287.

Richard Warwick Plymouth Marine Laboratory Prospect Place West Hoe Plymouth PLl 3DH UK

New Perspectives in Sponge Biology, edited by Klaus Riitzler; Smithsonian Institution Press, Washington, D.C.; 1990; 533 pp.; US$ 50.00, GBP 38.95; ISBN O-87474-784-8.

The study of sponges is a neglected branch of zoology. In no other major group of marine invertebrates would it be conceivable to hold an international confer- ence which would cover all aspects of the group, from their palaeontology to biochemistry, physiology, and ecology. Sponge biologists have convened four such international conferences since 1968. The first was held in London and its proceedings published as “The Biology of the Porifera” (Fry, 1970). This was followed by the second conference in Paris in 1978 (Levi & Boury-Esnault, 1979) the third in Woods Hole, Massachusetts, USA in 1985 and the fourth in Amsterdam in 1993. This book is the proceedings of the Massachusetts conference and contains 70 papers presented at that conference. It is a large volume of 533 pages in A4 format, with the text set in two columns in a proportional font and bound in hard covers. This contrasts with the 1979 volume in soft covers and courier type and says much for the advances in computer typesetting and its role in the production of minority interest books, which can now be produced to the highest standards.

Sponges are an ancient group of animals which have always been of great