Marine Macroecology Stability and Develops a Series of Hypotheses About How J.D
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Marine Ecology. ISSN 0173-9565 Book Review Marine Macroecology stability and develops a series of hypotheses about how J.D. Witman & K. Roy (Eds) speciation works in tropical and higher latitudes. In Chapter 2, Li provides quantitative information on spatial patterns of diversity, abundance and distribution of mar- Chicago: The University of Chicago Press, 2009. 424 pp. ISBN-13: 978-0-226-90411-5 (cloth) $95, ISBN-13: 978-0-226-90412-2 (paper) ine plankton. Technological innovations open new oppor- $40. tunities for macroecological analyses of microorganisms. He shows that allometric scaling of abundance and body It is impossible to understand the large-scale patterns and size is generalizable from plankton to fish; the conclusion processes in ecology by extrapolating from small-scale is that biological processes in the pelagos share many studies conducted at local sites, an approach that has characteristics with those elsewhere but are peculiarly been so prominent in ecological research since the early shaped by the turbulent hydrodynamic environment. In 1970s (Brown & Maurer 1989; Brown 1995). The goal of Chapter 3, McClain, Rex and Etter focus on deep-sea macroecology is therefore to gain insights by applying the macroecology and its logistical challenges. Biomass, den- questions posed by ecologists to the spatial and temporal sity and body size all decrease with depth, presumably scales normally studied by biogeographers and macroevo- reflecting the exponential decline in carbon flux from sur- lutionists. In their introduction to this book, Jon Witman face production, and are linked to species diversity, which and Kaustuv Roy succinctly point out the historical con- peaks at intermediate depths. As in terrestrial and shal- text and recent developments of the macroecological field. low-water environments, species diversity in the deep sea Originally, macroecology was explicitly empirical, involv- declines poleward. The authors conclude that deep-sea ing statistical analyses of empirical information on species macroecology suffers from a lack of samples, from restric- abundance, diversity, body size and range size. It has now tions to few taxa, which limits generalizations, and should been expanded to include the development and empirical include experimental approaches and evolutionary per- tests of process-based models that seek to explain large- spectives. In Chapter 4, Roy & Witman review latitudinal scale ecological patterns. The increasing feasibility of con- and longitudinal gradients of species diversity in shallow ducting and replicating experiments on large spatial scales marine invertebrates. They show that patterns are studied has also opened up the possibility of experimentally test- for a few taxa only, mostly outside the tropics and typi- ing some of these models in the relatively new field of cally not at the species level. The latitudinal diversity gra- experimental macroecology. Research on macroecology dient is a general biodiversity pattern, but differences has largely been conducted on terrestrial biota, as is evi- exist between taxa. Moreover, regional anomalies are dent from published work (Brown 1995; Gaston & Black- widespread and it is unclear whether the gradient is pres- burn 2000; Blackburn & Gaston 2003) and from an ent in local assemblages or only at the regional scale. estimated one-order-of-magnitude difference between case Underlying processes that shape the gradients are studies published on terrestrial and marine organisms. discussed (e.g. species-energy hypothesis, historical This book on marine macroecology consists of 15 processes). Notwithstanding the above caveats, it is evident chapters organized in three parts, covering patterns that some of the most direct insights into how history (part I), underlying processes (part II) and experimental constrains present-day species diversity come from shal- approaches (part III). The six chapters of part I deal with low-water marine invertebrates. In Chapter 5, MacPher- pelagic to deep-sea environments, microbes, invertebrates, son, Hastings and Robertson provide a concise review of fishes and algae. Generalizations seem difficult. In Chap- latitudinal and longitudinal gradients, species range sizes ter 1, Valentine summarizes large-scale patterns of species and body sizes of marine fishes, including data from a distribution and diversity in the world oceans, building broad range of shallow- and deep-water environments. the environmental and ecological framework for under- Their findings suggest many similarities with marine standing processes responsible for large-scale diversity invertebrates but strong differences with marine macroal- gradients. He concludes that processes determining gae. They conclude that, within ocean basins, patterns are the diversity of species pools are related to environmental controlled by currents, but that between basins, historical 256 Marine Ecology 32 (2011) 256–257 ª 2011 Blackwell Verlag GmbH Book Review processes are of primary importance. In Chapter 6, Sante- are difficult to interpret and require more case studies. lices, Bolton and Meneses present a much needed synthe- Species could be at greater risk of extinction than previ- sis on the large-scale distribution and diversity of marine ously thought, but careful assessment depends on com- algae. Macroalgal species richness does not always pleteness of inventories. Each new generation of fisheries increase toward the tropics, and latitudinal gradients dif- scientists faces an altered set of initial conditions and is fer strongly between brown, green and red algae. Coast- therefore prone to the shifting baseline effect. Part III of line length is a good predictor of regional species the book introduces the new field of experimental mac- diversity, which is also influenced by oceanographic fac- roecology, which involves testing process-based hypothesis tors. The six chapters of part II provide a process-based using relatively small-scale experiments replicated over explanation for marine macroecological patterns. In regional to global scales. In Chapter 13, Witman & Roy Chapter 7, Nee & Stone explain the ‘paradox of the point out that experimental manipulations remain the plankton’, the phenomenon that so many species of only direct means of testing process-based hypotheses and plankton can coexist in what appears to be a homoge- that the low site replication is therefore a key problem in neous habitat through a combination of niche differentia- experimental marine ecology. However, historical pro- tion and the presence of specialist parasites. They cesses are beyond the scope of experimental approaches. emphasize that we are in the middle of an extraordinary In Chapter 14, Sanford and Bertness introduce the period of plankton diversification and that major discov- comparative experimental approach. It uses identical eries are primarily being made by modern molecular experiments replicated along broad spatial gradients to biology. In Chapter 8, Leichter & Witman outline ocean- understand latitudinal variation in species interactions ographic processes that create large-scale patterns in the and links geographic variation in predation to large-scale ocean’s biota (e.g. ENSO, internal waves, upwelling). They gradients in the physical environment (e.g. temperature, suggest more explicitly linking macroecological patterns coastal upwelling). Finally, in Chapter 15, Connell & to oceanographic phenomena, which, however, are fre- Irving study interactions between canopy-forming kelps, quently episodic. This will require time series data. In algal understorey, and grazers and suggest that regional Chapter 9, Gaines, Lester, Eckert, Kinlan, Sagarin and patterns derive from local processes. They stress the Gaylord review our knowledge of dispersal and focus on importance of considering both broad-scale patterns and the link between dispersal and species ranges. They con- local experiments to understand the regional context and clude that there is little relation between range size and the unambiguous information at local scales. dispersal ability of species. This means only weak support This book is a wonderful tour de force introduction to for the general hypothesis that, in marine populations, marine macroecology through environments and across species attain maximum abundance in the center of their taxa. It is aimed at students and established ecologists, ranges. In Chapter 10, Clarke evaluates the role of tem- and it should strongly remind us that small-scale experi- perature in regulating marine diversity and concludes that mental ecology is not the only way to do sound ecological history rather than temperature is the primary driver of science. In fact, from the days of Darwin and Wallace marine diversity gradients. Temperature may influence into modern times, most large-scale patterns that so fasci- diversity through its effects on life history, but a full nate us were recognized and explained by empirical scien- understanding can only be achieved by integrating ecol- tists (Brown 1995). ogy and physiology with climatic, tectonic and oceano- Martin Zuschin graphic changes. In Chapter 11, Connolly relates University of Vienna, oceanographic and environmental variables to species dis- Department of Paleontology, tributions. The suggestion is to develop predictive, pro- Vienna, Austria cess-based macroecological models that can be tested using observational and experimental instead of regres- References sion-based approaches. Historical data on changes in distribution