LIBRARY LETTERS


ENVIRONMENTAL ENRICHMENT SHOULD BE SECOND NATURE

Shepherdson, D.J., Mellen, J.D. & Hutchins, M. (eds) (1998). Second nature: environmental enrichment for captive animals. Smithsonian Institution Press, Washington, D.C. xx+350 pp., figs, tables, photos, index. Hardback: Price ú25.25. ISBN 1-56098-745-6.

The Victorian zoo exhibited wild animals to the curious public eye as collectors’ items found in a distant and exotic world. In the zoo environment, however, that world was tamed into submission and ceased to exist. This ambiguity in our relationship with wild animals persists today. We bring animals into the human sphere for closer study, but keep them in ways which severely limit their ability to express natural behaviour. Thus we degrade the very thing we seek to know and preserve: the rich variety of animal life.

The book Second nature addresses this imbalance. It advocates that if we are to create an adequate captive environment—a ‘second nature’ for animals, so to speak—we must put the behavioural and psychological needs of the animals first. The book's aim is to develop a theoretical framework which helps us to define these needs, and to accommodate them through effective environmental enrichment. The book brings together various experts who discuss different aspects of this overall theme. These experts mainly work in the field of zoo biology; however, their contributions should appeal to a wider readership. They describe a wealth of experience in considering the quality of life of individual animals, and show a refreshing enthusiasm for bringing about change.

In the introduction, David Shepherdson sets the stage for a ‘science of environmental enrichment’. He puts this concept in historical perspective and discusses its relationship with several areas of scientific research, notably that of animal awareness. This discussion, however, does not include much recent literature, and makes little mention of relevant work on laboratory and farm animal welfare. His argument thus remains very general and lacks theoretical sharpness.

The first part of the book presents various interesting theoretical perspectives on environmental enrichment. John Seidensticker and Debra Forthman discuss how ecological and evolutionary theory may inform the understanding and preservation of behavioural competence in zoo animals. Joy Mench gives a clear and constructive account of the importance of explorative behaviour for animal welfare. She is one of the few authors who also covers the farm animal literature. Michael Kreger and co-authors consider how management goals of zoos, and the context in which these are implemented, play a crucial role in setting priorities of enrichment. Their discussion is comprehensive and to the point.

The second part of the book evaluates the effectiveness of different measures of environmental enrichment in relationship to various management goals. One such goal is the reintroduction of captive zoo animals into wild habitats. The chapters by Brian Miller and colleagues and by Ines Castro and co-authors provide systematic reflection on the importance of cage enrichment for successful reintroduction. They show that the relationship between enrichment and survival in the wild is not straightforward and needs careful evaluation. Kathy Carlstead usefully reviews the effect of enrichment on stereotyped behaviour patterns in zoo carnivores. She concludes that method and frequency of feeding are of primary importance in reducing stereotypes.

The third part of the book discusses strategies of enrichment for various phylogenetic groups, including amphibians, reptiles, ungulates and marine mammals. These chapters provide an extremely detailed evaluation of the relationship between the captive environment and the behaviour of numerous captive species. In particular, the chapters by Marc Hayes and colleagues on amphibians and reptiles and that by Debra Forthman on ungulates stand out. Forthman neatly sums up the general tenet of the book, suggesting that ‘a word like enrichment, which specifically describes actions to “enhance” or “improve” a deprived environment, should no longer dominate our thinking as we manage or design new facilities . . . Instead, we must plan to provide optimal conditions in every aspect of our care of confined animals’ (page 236). Surely no small task, but one worth aiming for, as the editors of the book outline in a concluding epilogue.

The book has set itself a tall order by proclaiming to strive towards a theoretical foundation for a science of environmental enrichment. On evaluation, I feel that despite its richness of content, it does not quite live up to this claim. The book's strong point is that it presents an enormous amount of empirical information on what does or does not constitute effective enrichment. And several chapters do indeed provide useful and interesting theoretical perspectives for evaluating this information. However, with a few notable exceptions, there is a striking absence of reference to definitions and models of animal well-being developed in closely related fields, such as that of farm animal welfare. Admittedly farm and zoo environments provide very different contexts for considering animal welfare. However, on a fundamental theoretical level, surely the concerns and interests of these research areas are similar. If zoo biology wishes to contribute to a fundamental understanding of animal needs, it should include and evaluate work done in other fields. This will focus and sharpen the questions and problems that it wants to address, and enable it to make a unique contribution to the science of animal welfare.

In conclusion, the book Second nature provides a rich and instructive overview of efforts by zoo biologists to develop a ‘science of environmental enrichment’. It is well worth reading, and should stimulate further work in this direction.

Francoise WemelsfelderScottish Agricultural College,Edinburgh, U.K.

ECLECTIC THEMES IN ECOLOGY AND ENVIRONMENT

Ambasht, R.S. (ed.) (1998). Modern trends in ecology and environment. Backhhuys Publishers, Leiden. viii+362 pp., figs, tables, index. Hardback: Price US$125.00. ISBN 90-73348-860-2.

This book contains an introduction by R.S. Ambasht followed by eighteen single authored and co-authored contributions covering a wide range of ecological themes. The aim of the book, as stated in the preface and in the introduction, is to describe modern ecological and environmental topics from a fundamental to an advanced level. Presumably, this would benefit both students and researchers by providing a comprehensive, up-to-date and accessible account of the latest trends and advances in the ecological and environmental sciences. When judged individually, some of the contributions seem to achieve this aim by providing excellent reviews on specific topics. Yet when judged as a whole, the book fails to provide the broad overview, or synthesis, of ‘modern trends’ expected from the title. It is also disappointing that so many contributions are let down by poor text editing.

Studies of the environment span so many fields of research that any attempt to describe the multitude of new developments is probably impossible in a single volume, and perhaps the editor should have renamed the book simply ‘Modern trends in ecology’. Instead, the editor chose to include the ‘environment’ but failed to explain why certain environmental subjects were chosen and others were left out. The preface and the introduction also fail to provide any clear rationale for the ordering of chapters, and there is little discussion of how the contributions link and interrelate. This leaves the reader to navigate through the rest of the book largely unaided. After reading the introduction, I also wondered why the book aimed to describe modern ecological topics at ‘both a fundamental and advanced level’. It is certainly difficult to do both, especially when most contributions are relatively short. As expected, I found that chapters varied widely in their accessibility to the non-specialist, and this makes it difficult to define a target audience for the book. Beginning the book with G.P. Patil's fairly advanced chapter on ecological statistics is certainly not the best way to inspire confidence in the non-specialist!

Considering the varied nature of the contributions, it is unlikely that many would read the book from cover to cover, and it is certainly impossible to critique all of the chapters here. While many chapters are essentially progress reviews in specific fields, such as chapter 4 on ‘Vegetation analysis’ by R. Pott and chapter 9 on ‘Recent advances in remote sensing of wetlands’ by J.M. Melack and L.L. Hess, some chapters also offer recommendations for environmental policy and/or future research directions. For instance, in chapter 3 on ‘Ecotoxicology’, B. Markert and J. Oehlmann write persuasively of the dangers associated with chemical pollutants which inhibit hormonal signals (endocrine disrupters) and they suggest ways of gathering further information about the environmental effects of these chemicals. In chapter 6, W.B. Jackson provides a fascinating account of the ecology of rodent pests in cities, combined with straightforward prescriptions for rodent population control, and chapter 11 by L. Ryszkowski has a similar applied focus in recommending agricultural techniques which reduce ecosystem damage and enhance nature conservation. The final chapter by N.A. Robinson is the most prescriptive of all. Dealing with environmental legislation, it contrasts markedly with the previous chapters which are all on scientific or technological topics. Although initially sceptical, after reading the chapter I concluded that it does make a fitting end to the book by placing much of the science described in earlier chapters within the wider context of legislation and policy making. I am sure that no ecologist would argue against the importance of increasing dialogue and co-operation between scientists and legislators, and N.A. Robinson discusses how such dialogue is essential for defining the objective criteria of environmental legislation.

As a whole the book may be rather eclectic and disparate, yet this in itself is not a major flaw, since this is symptomatic of many other edited books which are multi-authored and produced on a tight time schedule. However, the standard of editing is really not acceptable, especially for such an expensive book. The text is littered with spelling mistakes and grammatical errors which could have been easily corrected at the reviewing stage. Just read the preface to gain a sense of the kinds of mistakes which are prevalent throughout the book. There are even places where whole sentences or paragraphs are repeated word for word, such as on pages 93 and 94 of chapter 5. The formatting is also inconsistent through the chapters. For instance, some chapters have abstracts while others do not, and the final chapter breaks form with previous chapters by omitting numbered subsections and by using end notes rather than citing references within the text. Even the spelling is inconsistent between chapters with both U.K. and American variants of English used. Because of the wide range of topics and the lack of careful editing, I would not recommend buying this book for personal use. However, it would make a useful library acquisition.

David E. AndersonSchool of Geography,University of Oxford, U.K.

SPACE FOR THEORY

Tilman, D. & Kareiva, P. (eds) (1997). Spatial ecology: the role of space in population dynamics and interspecific interactions. Monographs in Population Biology, 30. Princeton University Press, Princeton. xiv+368 pp., figs, tables, photos, index. Paperback: Price ú25. ISBN 0-691-01652-6. Hardback: Price ú59.50. ISBN 0-691-01653-4.

The ecological world is full of spatial structure—you need look no further than your nearest lawn to see this. Field ecologists have long recognized the existence of such structure and its potential importance for ecological processes, but theorists have not been overly anxious to take on board this awkward fact of life. This lack of enthusiasm stems from knowing just how hard it is to deal properly with space. But the case for putting in place a proper formal theoretical framework to deal with space is urgent. We are now in the age of landscape ecology, born of remote sensing, GIS, and the need to manage ecological systems at large spatial scales. Without a proper theoretical framework, we are in danger of drowning in the enormous quantities of data emerging from such studies.

Spatial ecology is a multi-author text that brings together many of the household names in theoretical ecology in a review of the state of the art of the theory. As the authors point out, it is not a book that will provide a full review of the subject area, nor is it a book that will give you a complete introduction to the skills you would need to embark on research in this area. Rather it gives a taste of various aspects of spatial theory for those who are curious to see what is going on in this subject area.

Broadly, theorists are using two approaches to incorporate space into ecological dynamics (Tilman, Lehman & Karieva). The first is spatially explicit, with plants or animals referenced by location, the idea being that individuals move around in space and give birth and die at rates which depend on the presence of other individuals in some neighbourhood. Spatially explicit modelling has become a major activity in recent years as high-speed computational facilities have become widely available, and several chapters in the book illustrate this kind of approach. Most often location is resolved to the level of cells on a discrete spatial lattice (cellular automata, see Hassell & Wilson, and Holmes), but there is also increasing interest in continuous space (Pacala & Levin). Related to this are approaches which use local density and deal with dispersal through reaction-diffusion equations; these have a long and distinguished history in mathematics, but have been rather inaccessible to most ecologists. Lewis describes some interesting developments in this area to deal with the occasional long-distance dispersal events. The second approach removes explicit information about space, and is exemplified by metapopulation models and their derivatives (chapters by Hanski, Tilman & Lehman).

Does space actually matter for ecological dynamics? Opinions differ on this. Some chapters argue the case and give examples to show that ecological processes are quite different once spatial effects are incorporated. But Roughgarden argues that production functions, the basic ecological underpinning for sustainable resource management, are not fundamentally affected by space. Perhaps it is too soon to be sure, but it looks to me as though space will change processes as basic as single-species population growth, with abundance at equilibrium varying from zero to values much in excess of that predicted by mean-field dynamics.

For all the good ideas, there is a sense of frustration in reading the book—you pass from one formal framework to another without a proper structure to hold them together. It is as though theoretical ecology is full of little gadgets designed to suit particular problems, with little idea of the underlying machine which itself constructs the gadgets. This is not so much a criticism of the book, which simply reflects the state of the art in ecology, as a concern about the unsatisfactory state of theoretical ecology itself.

But there are some signs of progress towards a unified theory. Pacala and Levin show that it is possible to derive macroscopic models of population dynamics from individual-based stochastic processes. The idea is that small-scale spatial structure—for instance, the tendency of plants to develop into clumps—can be captured by the dynamics of second spatial moments. This is a new departure for theory; classical theoretical ecology, including Lotka-Volterra systems and much else forming the foundations of our ecological ideas, is concerned only with the first spatial moment (mean density). The work of Pacala and Levin points the way towards a new era in theoretical ecology in which the changing spatial structure through time will be described by the dynamics of the second spatial moment, or related measures. This will not resolve all the issues in scaling up from individuals to populations and communities, but it will be an important step in the right direction.

In the longer term, I look forward to a time when theoretical ecology has a proper core in which the different modelling frameworks, so well exemplified by this book, will be understandable as limits of a coherent underlying theory.

Richard LawDepartment of Biology,University of York, U.K.

WILL IT MAKE THEM THINK?

Botkin, D.B. & Keller, E.A. (1998). Environmental science: Earth as a living planet. Second edition. John Wiley & Sons, Inc., New York. xxxii+702 pp., figs, tables, photos, glossary, index. Hardback: Price ú23.95. ISBN 0-471-15782-1.

Many comprehensive textbooks on environmental science have appeared over the past thirty years. The thirty chapters of this book, grouped in seven parts, cover the usual breadth of material found in such texts and corresponding lecture courses, i.e. basic issues, earth as a system, ecosystems, resources, energy, water, air, environment and society. It is a familiar catalogue and doubtless satisfies a demand by North American students, although exactly at what college level is not clear. An eulogy by a senior student in a student-to-student preface suggests a senior level class, although the authors’ goals speak of ‘an up-to-date introduction’. The level of treatment varies from the relatively advanced (e.g. chapter 24 on ozone depletion) to some extremely simple sections at a level equivalent to GCSE (c. 15–16-year-olds) in the U.K. (e.g. chapter 26 on urban environments). The Earth's Biomass, which stands awkwardly as a free-standing section, and is not even numbered as a chapter, receives a very elementary treatment too. Was this an afterthought, a late addition?

As with many such textbooks, the sheer volume of factual material contained between the covers is impressive. On any quantitative index of ‘facts per penny’ the book would score highly, and therefore might be regarded as value for money. Superficially, too, the physical presentation might impress. The paper and artwork are glossy, there are diagrams in glorious technicolour, and the colour photographs are more at home in the Sunday magazine supplement. However, one has to question the pedagogic value of many of the photographs, which seem at best to be included for visual effect rather than academic content, and at worst can have unhelpful captions (e.g. Fig. 9.1 of old lead tailings in the U.K.) or be simply unclear (e.g. Fig. 9.3 of revegetation). Also, do we really need so many photos of irrelevant ethnic and archaeological artefacts? By including them are we not tacitly admitting that our story is not interesting and exciting in its own right, that we might have to embroider it with paraphernalia? The diagrams are mostly useful, although some are of such simplicity that one wonders why they are there, and others are not entirely accurate (for example the global map of vegetation production, Fig. B4).

Books of this scale are the results of teams rather than individuals. Here the acknowledgements list all those involved including reviewers, evaluators and focus groups, from staff and students alike. The United States bias of the book is revealed by the fact that only one reviewer, a Canadian, came from outside that country in the first edition; the number has been doubled to two Canadians in the second edition. If the enormous amount of factual material were not enough already, many supplements are available as aids for further study and teaching; these include recent reviews, regional case books, student CDs, an instructor's manual, a test question bank, transparencies, CD-ROM, and Environet website. With so much material being thrown at the brain of the poor student, what is likely to be the result? An omniscient polymath? A free-thinking expert, able to think through solutions to the many multifaceted environmental problems facing us in the twenty-first century? Either or both would be very acceptable but one fears that this book will provide neither.

The main reason for making such a sweeping and provocative assessment lies in the failure of the book to grapple with the question ‘why?’ If the main aim is to assemble as much factual material as possible, as here, one produces an encyclopaedia, not a textbook. Very good, with the aid of the references cited too, for looking up the latest factual position on, say, Sudbury, Ontario, or the state of ventilation of aeroplanes. But less good in making the student think or develop their powers of reasoning to formulate specific solutions, which is surely the aim of an environmental science education? Two examples taken at random will illustrate this. The student will read this book and learn that the atmosphere of London has become cleaner since the 1950s as natural gas has replaced coal, but they will not know why this has occurred. Economics? Availability? Legislation? A second example would be the ‘urban heat island’. Why and when does it form? Not simply due to the burning of fuels, but very much related to the radiative properties of building materials. If the emphasis could, at particular points, be directed to processes rather than facts and factors, one feels it would be more useful educationally.

If one is looking for an environmental science factbook, this could be the one to consider, and doubtless it will fill a niche in the North American college market. However, one is reminded of Lord Rutherford's famous dictum on science and stamp collection; the present book is very much in the second camp. If one seeks to impart a sense of enquiry to the student—something inspirational and not just informative—one might be better looking at something by A.S. Goudie (1992) or I.G. Simmons (1996).

Ken AtkinsonSchool of Geography,University of Leeds, U.K.

REFERENCES

Goudie, A.S. (1992) Environmental change, 3rd edn. Clarendon Press, Oxford

Simmons, I.G. (1996) Changing the face of the Earth, 2nd edn. Blackwell, Oxford

DIVERSITY AND DANGERS IN HUMAN DESERTIFICATION ISSUES

Clarke, J. & Noin, D. (eds) (1998). Population and environment in arid regions. Man and the Biosphere Series, Volume 19. UNESCO and Parthenon Publishing Group. xxv+384 pp., figs, tables, index. Hardback: Price ú45.00. ISBN 1-85070-962-9.

This book, based on papers presented at a conference at the University of Jordan in Amman in October 1994, contains seventeen diverse case study chapters on various aspects of population-environment relations in drylands, topped and tailed by the editors’ introductory and summary chapters. Arid regions are here defined according to climatic criteria to include the hyper-arid, arid and semi-arid zones. The majority of papers concentrate on Africa, while some are concerned with parts of the Middle East (Syria and Jordan) and one focuses on Spain.

Not all editors of conference proceedings realise that turning a collection of papers into a book is not just a simple matter of collecting the contributions and sticking them together, but these editors are not so ignorant. They do a generally good job in setting the scene, both geographically and thematically, in Chapter 1, although I do not agree with their insistence on calling arid regions ‘fragile’ environments. It is also unfortunate that they use the FAO/UNESCO 1977 desertification map to show actual desertification, while the map was always intended to depict an estimate of desertification hazard. Indeed, the very idea that a single global map can show desertification at all is now widely agreed to be erroneous.

The chapters in the main body of the book encompass a wide range of subject matter varying in spatial scale of analysis from individual households (a theoretical look at population dynamics and environmental interactions) to broad regions such as North Africa (an overview of species loss). More specific case studies adopt a similarly broad range of methodologies, from a remote sensing study of vegetation change along Egypt's coastal zone, to archival research on dryland Spain, and an intelligent analysis of the complex issue of biomass fuel use in central Sudan using a number of physical and social indicators. The adaptability of traditional societies is highlighted in several contributions, as are the benefits and dangers of adopting modern technologies.

Perhaps one of the most pressing concerns currently facing governments of dryland countries, that of water availability, receives little attention in this book, but many other issues are covered from a variety of viewpoints. Throughout the book, the complexity of population-environment relations in drylands is made clear time and time again. While natural physical factors obviously affect many human activities, not least in the extremely uneven distribution of population in arid regions, the resilience of societies to the variability of the natural dryland environment is also evident. The editors’ summary provides a very cogent synopsis of the issues addressed to round off a valuable addition to the literature on this important area of study.

Nick MiddletonSchool of Geography,University of Oxford, U.K.

A ROSE BY ANY OTHER NAME . . .

Herendeen, R.A. (1998). Ecological numeracy: quantitative analysis of environmental issues. John Wiley and Sons, New York. xxiii+331 pp., figs, tables, photos, index. Paperback: Price ú34.95. ISBN 0-471-18309-1.

It isn’t quite ‘A boy named Sue’, but still this excellent book is rather oddly named. It certainly fulfils the promise of its subtitle by delivering a quantitative perspective on a range of environmental issues: but it is really only peripherally concerned with ecology. Yet if your students ever need to attach numbers to human activities, or to human damage in the natural world, this book is a good starting point.

From the first refreshingly-written pages, it is easy to see that this is a text with a mission. The Foreword tells us of ‘the head-viscera disconnect’ and of concepts which even the mathematically literate ‘. . . know in their heads but quite possibly not in their guts’. The book's central idea is that relatively straightforward mathematics can capture the quantitative essence of a wide range of environmental issues, and so can stimulate more intelligent and considered decision-making. The first part of this notion isn’t new, of course: Harte (1988) introduced it to a generation of ecological and environmental modellers. Herendeen's book differs from its worthy predecessor mainly in covering a wider range of themes and in being more accessible to those with only moderate mathematical skills. It is also quite obvious here that the author cares about the issues which he covers: and I would suggest that this adds a good deal to the book's appeal.

Based in the University of Illinois, Robert Herendeen has a background in physics and has worked extensively in energy conservation. Energy is indeed a common thread running through the chapters of this book, increasingly so in later chapters. The approach enables the author to draw parallels between ecological and economic systems, effectively using energy as a common currency. A fine idea: but as the author admits (and clearly points out), this is a linkage which is fraught with difficulties. Nonetheless, it permits some intriguing juxtapositions: where else would you find a chapter which brings together the concept of residence time and the changing styles of blue jeans?

The book is advertised as suitable for advanced undergraduate students. Chapters increase noticeably in difficulty through the book, but each is sufficiently self-standing to be useful individually. The underlying mathematics is always explained crisply and clearly and is nowhere excessively demanding for the intended audience: occasional more abstruse asides are marked as optional. The author indeed shows admirable restraint in places, taking us right to the edge of the cliff for chaos theory in the chapter on ‘Dynamics, stocks and flows, age class effects’, game theory in ‘Shared resources and the tragedy of the commons’, self-organization and emergence in the chapter on ‘Ecological economics and sustainability’, and statistical dynamics (à la Prigogine) in a final chapter on ‘Thermodynamics and energy efficiency’. Each of these would provide fine jumping-off points for more advanced work. Every chapter ends with a number of exercises, some of which need a spreadsheet.

The non-U.S. reader will find a stateside bias but (in general) this is not irritating, with the exception of the U.S. units which crop up rather too regularly. Discussion of U.S. policies (e.g. in the chapter on ‘Indirect effects’) may well also be somewhat lost on non-U.S. readers. But in every other respect the book succeeds in presenting a widely-applicable approach to environmental modelling. It does not fall into the trap of concentrating on individual software packages, for example, but does suggest useful web sites for data gathering.

Off-target title aside, does the book succeed in its mission? As much as the author might like to see his book used for environmental decision-making in both treehouses and boardrooms, one might suspect that—for a while at least—most of such policy issues will continue to be decided more by viscera than heads. But I shall certainly use this in my teaching.

David Favis-MortlockEnvironmental Change Unit,University of Oxford, U.K.

REFERENCE

Harte, J. (1988) Consider a spherical cow: a course in environmental problem-solving. University Science Books, Mill Valley, CA

OASES IN THE TROPICS

Laurance, W.F. & Bierregaard, R.O. Jr (eds) (1997). Tropical forest remnants: ecology, management and conservation of fragmented communities. The University of Chicago Press, Chicago. xv+616 pp., figs, tables, photos, index. Paperback: Price ú30.50. ISBN 0-226-46899-2. Hardback: Price ú83.95. ISBN 0-226-46898-4.

Across the tropics forests are being cleared and fragmented. Whereas much attention is rightly paid to preserving what is left, and analysing the causes and scales of destruction, a gap in the literature has concerned the fragments that are left. At last, a book on what is known about fragments is available.

This book presents a large and pragmatic cross-section of approaches taken in community forestry participation worldwide. In highlighting case studies from Asia, Africa and South America, it considers types of forest that the all too broad term ‘community forestry’ currently encapsulates. These include agroforests, limited timber extraction forests, and national parks. Each geographical site presents different challenges and foci for community participation in forest assessment, depending on communities, governments and locations.

At about ú30 the paperback is affordable within the U.K., though it is perhaps rather less so to the offices of the sorts of field projects presented in the book. The format is pleasantly spaced. The index is adequate—many topics unfortunately appear as inserts under country names, not as independent items. Students will appreciate useful highlights by the editor in the margins of case studies, which contribute to understanding without interfering with the flow of reading.

The editors are to be congratulated for bringing together this breadth of experience, and in particular because the individual chapters would, in all likelihood, be otherwise lost in the realm of project ‘grey literature’. It is excellent in presenting a study guide through real life, and current examples that would be unlikely otherwise to enter academic training literature. As such, it is an example to be followed.

The case studies in the book, and in particular the Cross River State (Nigeria) example, are not all-hopeful stories. This is refreshing to see in a literature too often dominated by politically correct and wishful thinking. There is no guarantee that community forests in the hands of empowered communities will sail into a happy never-never land where people will stay the same over future generations, safeguarding their resources. This has happened nowhere at any time. From ancient Indian tribes in what is now the U.S.A., to Dayaks in West Kalimantan and elsewhere, humankind over-exploits when convenient. Communities, whether a village, nation or civilization, evolve in their own ways. And this creates tensions and conflicts over many of the resources covered in this book.

Implementation issues are well presented, from both technical and social points of view. The book's longest chapter, concerning East Kalimantan (Indonesian Borneo), provides the widest spectrum of considerations in a community forest project, and from many angles. These include the roles of NGOs and local government, inter- and intra-village considerations, timber forestry, community lands, protected areas, and the use and misuse of maps. The complexity is staggering and probably worth a book in itself. Contrast this with the chapter on Nepal, which appears to have a more cohesive set of linkages from government to local communities, allowing the case example to focus more on technical forestry considerations. The smorgasbord contained within the book ably shows how field implementation of community forest participation is dependent more on local conditions than any theory.

The book concludes by trying to tie its diverse chapters together, and providing a general checklist for what will be needed by future workers in this field. One issue that I would have liked to see clarified is that one cannot generalize on what ‘communities’ and ‘forests’ are. Given the scope of the chapters of this book, and the reality of community forestry worldwide, from the perception of a myriad of stakeholders, all that is sure is that communities are made up of people and forests are groups of trees. In a country where land is under state control, government may view the entire population as the community, and a village, tribe or clan group as merely a sub-set of a whole with no particular rights to their environs. Who has the right to say what a ‘community’ is? All stakeholders will have their own views and agendas, and it is up to them to come to consensus with whatever support that they can find. The concluding chapters are clear, however, in stating that local communities are not static and singular organisms. Would that others, especially in Western-based advocacy settings, realize the same.

This book does not, as some may first think, focus on communities and conservation of forests for biodiversity. Communities and conservation overlap in some chapters, in particular in a Ugandan case study looking at reducing pressure on conservation land while allowing limited harvesting. I hope that this series will expand to face that controversial topic more thoroughly, especially the concept of Integrated Conservation and Development Projects.

This book is to be highly recommended. It is intended to focus on undergraduate and post-graduate degree level courses. It will do well there, yet I think that it will also provoke reflection in readers directly involved in community forest and conservation projects in both developing and developed countries.

James K. JarvieHarvard University Herbaria,Harvard University, U.S.A.

FROM AAPA FENS TO ZOOXANTHELLAE

Calow, P. (ed.) (1998). The encyclopedia of ecology and environmental management. Blackwell Science Ltd, Oxford, U.K. xv+805 pp., tables, figs, black-and-white photos, colour photos. Hardback: Price ú125.00. ISBN 0-86542-838-7.

This encyclopaedia is said to ‘provide a guide to the core definitions and issues associated with pure and applied ecology’ (dust cover). This has been achieved by enlisting the help of over 200 scientists. There are nearly 3000 entries, organized in the only sensible way—alphabetically. The length of the entries varies from pithy single sentence statements to longer entries for basic terms or those that are deemed particularly important, such as conservation, motor vehicle pollution, sublittoral zone and thermometry. It includes also a large number of acronyms, e.g. GEOSAT, LCA, NIMTO and SAM, which are then discussed under their full title, so if any of these is unfamiliar this is the book for you. However, PAN (as plant available nutrients not as peroxyacetyl nitrate, which is included) and PAM (plant available moisture) are missing. The list of possible terms for inclusion, however, is almost endless and each user will have their own idiosyncratic list of desired definitions. In the preface this difficulty of the selection of terms towards the periphery of the subject is recognized and in the end the editors have done a good job of providing a broad coverage of a variety of terms of both a general and a specific nature.

The entries generally fall into a number of categories. Firstly, there are those concerned with aspects of the abiotic environment, including climatological, geomorphological, pedological and hydrological terms. Secondly, there are definitions relating to aspects of the functioning, interaction and distribution of biota. This category could also include the various ecological theories, e.g. optimal foraging, succession and the precautionary principle and concepts such as that of the species. There are descriptions also of the major world biomes and ecosystems, with good cross-referencing to associated taxa, ecological terms, environmental problems and related habitats. Individual species do not, of course, get an entry, with most references being at the level of order, or above in the taxonomic hierarchy. A welcome inclusion is that of a variety of statistical techniques, ranging from simple hypothesis testing, complete with appropriate equations, to multivariate analyses like ordination, as well as descriptive indices such as those relating to diversity, fitness and productivity.

On the applied side there are short sections on environmental issues such as acid precipitation, eutrophication and other forms of pollution, as well as on aspects of environmental rehabilitation such as introduction, reintroduction and ecological restoration. Various theories associated with environmental management also are covered, such as risk assessment, environmental quality standards and best available techniques. There is information on the major bodies and groups involved with the environment, both governmental organizations (e.g. United Nations Environment Programme, Species Survival Commission) and non-governmental organizations (e.g. ‘Greens’). Aspects of environmental legislation also are covered, including sections on environmental law, EU/EC environmental protection and United States legislation.

There is plenty of cross-referencing, both by putting in small capitals any headword that appears in another entry and by putting ‘see also’ at the end of an entry for related terms. There are occasional slips in the system, e.g. phanaerophyte should be in small capitals. In a number of instances when looking up a word one is immediately referred elsewhere, this can be irritating, but in reality it involves little more effort than using an index. The inclusion of an index, however, would help in the location of terms for which one is uncertain about the referencing. Usually there is limited referral to the literature at the end of the longer entries and sometimes the shorter ones too. A number of the entries are supported by figures and tables, not all of which are taken from other sources! They are uniformly clear and they have been used selectively to provide helpful support for the text. Also, there is a selection of black and white plates and twenty-six colour plates, the latter illustrating a range of ecosystems and organisms. In all my dipping into this book, I have yet to find a typographical error! It is impossible to cover every aspect of this vast tome, but hopefully the above has given a flavour of the mix of topics that are covered. The result is a smooth blend of material produced to a consistent, high standard and the editors are to be congratulated.

Given the plethora of dictionaries and encyclopaedias on the market, however, one has to ask why buy this one? It has a good breadth of ecological and environmental terms interspersed with those relating to the more physical aspects of the environment. It provides also a fuller description of terms than the equivalent dictionaries (e.g. Elsworth, 1990; Allaby, 1994a), and while other encyclopaedias are superficially similar (Allaby, 1994b; Ashworth, 1991) they contain less ecological depth. In the end, it is a matter of finding one that has both coverage and depth required, at a price to suit one's pocket. The Encyclopedia of ecology and environmental management is not cheap at ú125 and individuals might well prefer to spend their money elsewhere, relying instead on library acquisition. It would certainly be a very useful addition to the shelves of any library in a biology, environmental science or geography department. I have recommended it already to my College which does not have an equivalent reference encyclopaedia and I am sure that it will be well used by students wishing to clearify their understanding of key ecological and environmental terms.

Pam BerrySchool of Geography,University of Oxford, U.K.

REFERENCES

Allaby, M. (1994a) The concise Oxford dictionary of ecology. Oxford University Press, Oxford

Allaby, M. (1994b) Macmillan dictionary of the environment, 4th edn. Macmillan Press, London

Ashworth, W.(1991) The encyclopaedia of environmental studies. Facts on File, New York

Elsworth, S.(1990) A dictionary of the environment. Paladin, London

A RACE AGAINST TIME

Sillitoe, P. (1996). A place against time: land and environment in the Papua New Guinea highlands. Harwood Academic Publishers, Reading. xxv+438 pp., figs, tables, photos, index. Hardback: Price ú49.00. ISBN 3-7186-5925-5.

From mid 1997 to early 1998 Papua New Guinea suffered one of the worst droughts in living memory. Devastating fires and chronic food shortages were recorded across the region resulting in extensive damage to wet tropical forests and highly productive agricultural lands. This was not the first time that the indigenous population had experienced famine. Written observations from the early European explorers and the recorded oral histories of indigenous peoples talk of past episodes of extensive fires and starvation. The increase in human population on the island over the last decade has placed an added strain on Papua New Guinea's agricultural systems, leading to a renewed interest in the implications for sustainability of traditional agriculture and the general character of human-environment relationships.

In A place against time, Paul Sillitoe offers us a fascinating insight into the culture and environment of the Wola, who inhabit the southern flanks of the highlands of Papua New Guinea, between about 1600 and 2000 m altitude. Contrary to widely accepted assumptions that shifting cultivation prevails as an agricultural system in the tropics, the Wola (and other groups in the highlands) operate long-term continuous gardening of sites that have had little or no fallow period, at least within living memory. Furthermore, the crop yield in these permanent plots often improves with time, rather than experiencing catastrophic decline. The book attempts to integrate the viewpoints of both indigenous knowledge and environmental science in an analysis of the reasons why the Wola agricultural system is so successful.

A central theme of this work is the ‘relationship of Wola culture to the natural environment’ (p. xxiii), focusing, in particular, on the role of soil, a central agricultural resource, in the sustainability of traditional agriculture. The approach is a very objective one in which a vast amount of social and environmental facts—geology, landforms, climate, vegetation and Wola land management techniques—has been meticulously gathered and presented in the text and in tables. This represents one of the most comprehensive studies of traditional agricultural systems and makes an extremely significant contribution to, and integration of, environmental and ethnographic studies in Papua New Guinea.

Through careful consideration of the range of ethno-pedological factors, Sillitoe reveals that the success of the Wola gardens is due to the sustained productivity of sweet potato in a traditional technique of soil management known as mounding. In many parts of Papua New Guinea the soil is formed into circular mounds of varying dimensions sometimes with the addition of compost, though rarely with the success recorded in the Wola gardens. The argument is a convincing one, given the weight of evidence to support it, though a number of questions remain unanswered, in particular, what are the limits of production of these long-term mounded gardens?

This limit has been reached before in the Wola agricultural system, with infrequent but severe frosts and droughts causing catastrophic losses in production leading to food shortages. The response of the Wola during the ‘hungry times’ has been to attribute ‘the occurrence of these unforeseen events to unpredictable spirit-induced extremes in the weather’ (p. 101). Recourse to spiritual explanations for unexplained food shortages is probably as much a reflection of the relative infancy of the land management system as it is to the infrequency of abnormal climate events. The sweet potato was probably introduced into Papua New Guinea only around 300 years ago and the development of intensive mounding techniques to enable long-term production of this crop is even younger. While the present agricultural system would appear sustainable, its long-term future under increasing population pressure and environmental change remain unclear.

Climate events such as the 1997–98 El Niño may be the biggest concern for the Wola, and their neighbours, in the years to come. Certainly, without the knowledge of natural long-term climate variations and the susceptibility of different agricultural systems to these variations, no informed judgement can be made about the sustainability of present agricultural practices. Sillitoe clearly shows that if the land management practices of the Wola are to be sustained in the future then indigenous as well as scientific knowledge must be gathered to understand fully the potential impact of environmental change on these societies. This is the immediate challenge for anthropologists and environmental scientists alike, and whether this can be achieved or not . . . only time will tell.

Simon HaberleDepartment of Archaeology and Natural History,Australian National University, Australia

APPETITE WHETTER FOR RIVER BOTTOM RESEARCHES

Bretschko, G. & Helesic, J. (eds) (1998). Advances in river bottom ecology. Bachhuys Publishers, Leiden. ix+344 pp., figs, tables, index. Hardback: Price US$136.00. ISBN 90-73348-87-0.

‘River bottoms’ focuses on the zone of interaction or ecotone between surface water and groundwater. River ecologists have often considered their domain of interest to extend down to the light discontinuity within the river bed; a maximum depth of four to five times the mean particle size of the bed sediment. Beneath this surface layer, groundwater ecologists recognize a zone of surface water-groundwater interaction as the topmost layer of the groundwater system. Within the ecotone, physico-chemical gradients exist due to the mixing of surface water and groundwater, and to changes caused by biological and geochemical processes, the strength of which relate to residence time. Schwoerbel (1961) termed this zone of interaction between surface water and groundwater the ‘hyporheal’. Recognition of the ecological importance of this ‘river bottom’ biotope within alluvial sediments has a long history (e.g. Obrdlik et al., 1992). The sediment composition of the river bed/alluvial aquifer determines the dimensions of the hyporheic zone, both at the reach scale and locally, at the scale of an individual bedform. In many cases the hyporheic zone is of limited extent but in some geomorphological settings, notably glacial troughs infilled with highly permeable gravels, the zone may be extensive. Particular interest in this zone was stimulated by Stanford & Ward (1988) who defined the hyporheic zone of the Flathead River, Montana, as extending 10 m vertically and 1500 m laterally.

This volume is the selected proceedings of the fourth symposium on River Bottoms, which focuses on the vertical dimension of streams, held in Brno, in 1996. The first Czechoslovakian symposium ‘River Bottom I’ in 1986 was organized only for biologists. The second meeting in 1990, the third in 1993, and this meeting all involved a wider range of scientists, including hydrologists, geomorphologists and environmental chemists. The volume includes thirty-one chapters organized in four sections: The Biotope, The Energy Basis, The Consumer Community, Stream Fish, and River Management, although the last two sections together comprise only six papers.

The first two sections are especially valuable. The book opens with two useful introductory papers by Bretschko and Hildrew which, in the first, illustrates the nature of the river bottom biotope and, in the second, highlights three important aspects of the ‘river bottom’: its use as a refugia from high flows, the influence of disturbance upon species interactions, and the effects of disturbance upon community patterns. The first section emphasizes the importance of hydrological exchange processes within the bed and the spatial heterogeneity of habitats, defined by shear stress and sediment size, on the channel bed. Brunke et al. use a range of physico-chemical and particle parameters to delineate three areas within the hyporheic zone: areas of downwelling, areas of upwelling and areas of neutral exchange characterized by horizontal advection. Jorde and Bratrich develop habitat ‘preference curves’, based upon measurements of bed shear stress, for macro-invertebrate species and model the influence of bed morphology and flow pattern upon these species.

The second section focuses upon the energy sources to streams and the importance of organic-matter processing, especially by the microbial community, ‘biofilms’, in making organic matter available to animal consumers. Leichtfried, using protein, TOC and TON measurements, shows that the greatest amount of organic matter in a second order stream is 40–50 cm below the surface and that this relates also to meiofaunal and microbial distributions. The section includes three papers that explore the influence of flow variability upon the development of periphytic algae.

The major section of the volume includes thirteen papers on the consumer community and opens with a paper by Ward and Voelz which examines differences in community composition, diversity, and abundance of surface benthos and interstitial fauna along large-scale elevation gradients. Whilst the surface fauna show the expected correlation with elevation, and related variables (e.g. temperature), the groundwater fauna was largely decoupled from altitudinal gradient and appeared to respond to site-specific hydrological and geomorphic variables, such as porosity and hydraulic conductivity. Subsequent chapters examine specific macro-invertebrate taxa (chirnomids, mayflies), as well as the micro- and meiobenthos, and investigate not only the influence of flow-related habitat variations but also the functional roles of benthic and hyporheic organisms.

Finally, there are six papers that focus on management issues. Two papers address fish communities and impacts of siltation upon trout spawning grounds. Then, four papers cover sampling problems, the use of classification systems (here the ‘functional habitat’ approach), the assessment of in-river flow needs, and the transfer of scientific research into management practice.

‘River Bottoms’ reflects the strong tradition of research in hydro-biology in Brno and Lunz. The volume will be of value to anyone who whilst standing in a river has not questioned: what lies below? The vertical dimension is an important component of fluvial systems. This volume provides useful insights into the state-of-the-art of river bottom research and it contains a wide range of material to whet the appetite of ecologists and hydrologists alike.

Melanie BickertonSchool of Geography and Environmental Science,The University of Birmingham, U.K.

REFERENCES

Obrdlik, P., Castella, E., Foeckler, F. & Petts, G.E. (1992) Groundwater invertebrates of European alluvial rivers. Regulated Rivers Special Issue, 7, 1

Schwoerbel, J. (1961) Uber die Lebensbedingungen und die Besiedlung des hyporheischen Lebensraumes. Arch. Hydrobiol. Suppl., 25, 182–214

Stanford, J.A. & Ward, J.V.(1988) The hyporheic habitat of river systems. Nature, 335, 89–97

APPLICATIONS OF PCR IN MYCOLOGY

Bridge, P.D., Arora, D.K., Reddy, C.A. & Elander, R.P. (eds) (1998). Applications of PCR in mycology. CAB International, Wallingford, England. xv+357 pp., figs, tables, index. Hardback: Price ú60.00. ISBN 0-85199-233-1.

As a mycologist just embarking on the development of molecular probes to identify fungal mycelia in the field, like so many other ecologists, before reading this book I knew little more than that PCR makes it possible to considerably amplify selected DNA sequences from very small amounts of template DNA. The book has succeeded in providing me with a grasp of the rationale behind these molecular biology techniques. It is not a recipe book, but indicates where to look for precise information on techniques. Furthermore, the book demonstrates where PCR can be applied.

The book comprises fifteen chapters and a list of abbreviations, the latter being extremely useful since molecular biology seems to be even more filled with jargon and acronyms than other disciplines. The first two chapters (by Edel et al.) provide an overview of PCR and its use for gene cloning. Standard methodologies, including general principles, reaction components and conditions, practical considerations, and analysis of PCR products, are clearly expounded. In situ PCR, which allows the detection and cytological localization of nucleic acid sequences in whole cells, is likely to be an extremely valuable technique for fungal ecologists, and is briefly introduced. A range of PCR cloning strategies appropriate to filamentous fungi are reviewed, and some of the problems pointed out.

In Chapter 3, Benito and van Kan summarize the principles of DDRT (differential display reverse transcription)–PCR approach, which is a procedure for differential gene expression analysis. Again this is a technique which will be of use to ecologists working in situ, which is illustrated by a case study of their work investigating fungal gene expression in planta during the interaction of Botrytis cinerea with the host tomato plant.

The fourth chapter (by Bridge & Arora) is the last of the chapters dealing largely with methodology, and is aimed at interpretation of PCR for species definition. They consider the appropriateness of using one molecular technique or another in a particular situation, and the appropriateness of numerical methods, essential for analysis of the results of these various techniques. This is especially important if misinterpretation and the making of inappropriate taxonomic decisions are to be avoided. The introduction of PCR-based methods has already significantly increased the level of activity in fungal systematics, and is likely to have considerable impact on the study of ‘unculturable’ species (which may be up to 83% of known species!). This is illustrated later in separate chapters where application in phylogenetics (Takamatsu) and taxonomy of entopathogenic fungi (Drive & Milner) are detailed.

Chapters 5–14 all consider different applications of PCR in fungal biology; all are valuable contributions, though their appeal probably varies depending on the reader's particular area of interest. The value of the application of PCR techniques is clearly revealed. With regard to lichen-forming fungi it has already contributed to the understanding of phylogeny and is likely to continue to do so, while it could also help in the study of the tremendous diversity of chemical compounds in lichens (Crespo et al.). Likewise, the use of PCR-based techniques for identification and examining species relations has/will allow better definition of the presence and role of mycorrhizal fungi in the rhizosphere (Lanfranco et al.). As well as identification of fungi in the field the technique is extremely valuable in applied situations, including medical mycology (Hughes et al.) and mycotoxin production (Geisen). Its value in studies of lignocellulose degradation (Reddy & D’Souza) and in biotechnology in general (Burnett et al.), e.g. for characterization, cloning and expression of heterologous genes, are well covered.

Finally, Sreenivasaprasad and Mills point to the future. Clearly, the number of PCR-associated techniques is continually increasing. They predict that PCR is likely to be one of the most widely used tools in fungal biology for diagnostics and the study of genetic relatedness and genomics.

In the preface the editors state that they hope that the book will enhance the reader's ‘understanding of the technology and help them to gain new appreciation for the many potential benefits of PCR application’. It certainly did for me, and I recommend this book to any fungal biologist starting out in this field, and also to those who are looking for a ‘foot in the door’ into applications of the technique in mycological fields other than their own.

Lynne BoddySchool of Biosciences,University of Wales, Cardiff, U.K.

TESTING NULL MODELS

Gotelli, N.J. & Graves, G.R. (1996). Null models in ecology. Smithsonian Institution Press, Washington D.C. xvi+368 pp., figs, tables, index. Paperback: Price ú23.50. ISBN 1-56098-645-X. Hardback: Price ú50.75. ISBN 1-56098-657-3.

This is an important and useful book for both proponents and opponents of tests of null models in ecology. It gives a comprehensive coverage of both the general philosophy and history behind these tests and discusses their applications in nine specific areas of community ecology (diversity, abundance, niche overlap, temporal overlap, size, co-occurrences at different locations, species-area relationships, biogeography, and food webs). In the Epilogue, the authors point out some of the problems involved in constructing null models and suggest how these can be overcome. It is the only detailed review of work in this area, and should become the standard reference for some time. It is well written and gives an excellent introduction for biologists and others wishing to know more about this important subject.

The authors define a null model as ‘. . . a pattern-generating model that is based on randomization of ecological data or random sampling from a known distribution . . . designed with respect to some ecological or evolutionary process of interest. Certain elements of the data are held constant, and others are allowed to vary . . . designed to produce a pattern that would be expected in the absence of a particular ecological mechanism’. These models are used to see whether observed data could reasonably have arisen in the absence of the ecological mechanism being considered. For example, to test for interactions between species on islands, one might measure the amount of interaction that appears to exist for the species present on some real islands using a suitable summary statistic. The same statistic is then calculated for a large number of sets of data calculated using a null model which is ecologically realistic, except that it allows no interaction between species. If the observed summary statistic is typical of the ones generated using the null model then it is concluded that there is no evidence that interaction occurs. On the other hand, if the statistic for the real data indicates a level of apparent interaction that is much higher than usually occurs with the null model then it is concluded that there is evidence for interaction.

Computers started to become readily available to ecologists about 30 years ago, and this gave them the tools that they needed to test null models. Over the intervening years many such tests have been carried out, in some cases apparently contradicting what was expected from established ecological theory. As a result, the whole area of the testing of null models has been very controversial.

As a statistician who has become interested in the analysis of ecological data, I find the controversy interesting, and can to some extent see both sides of the arguments. My point of view is that, as far as I can see, little is really known for sure about how ecosystems operate so that these tests are essential for getting a better understanding of the component parts. I am reminded of Francis Galton's opinion that ‘it is the triumph of scientific men to rise superior to their superstitions, to desire tests by which the value of their beliefs can be ascertained, and to feel sufficiently masters of themselves to discard contemptuously whatever may be found untrue’. On the other hand, finding the ‘right’ null model is often difficult and subjective, and opponents of particular null model tests have often been justified in their criticisms of conclusions based on overly simple models. The authors of the book take the same view, so I very much sympathize with their approach. It is hard to know for sure, but I imagine that all except the most ardent opponents of null model testing will consider that the book is reasonably balanced.

The authors quote an anonymous reviewer of their book proposal who said that he or she was not a fan of the null model approach, and would not be disappointed if the project failed. However, the comment was also made that ‘we are doomed to have these ideas with us for a long time’. I am much more optimistic than that. I anticipate that as more becomes known about ecological principles, null models will become more realistic and make it possible to identify the relative strength of different ecological factors under different conditions. There is a long way to go, but this book is a good summary of where we currently are.

Bryan F.J. ManlyDepartment of Mathematics and Statistics,University of Otago, N.Z.

DOES BIODIVERSITY AFFECT SAVANNA FUNCTIONING?

Solbrig, O.T., Medina, E. & Silva, J.F. (eds) (1996). Biodiversity and savanna ecosystem processes: a global perspective. Ecological Studies Vol. 121. Springer-Verlag, Berlin. x+233 pp., figs, tables, index. Hardback: Price DM118.00. ISBN 3-540-57949-4.

Savannas occupy around 40% of the land surface of the tropics and form a major resource for large populations, especially in the largest, African, formation. Yet the level of interest and knowledge as judged by major texts published over the past 20 years is considerably less than that for tropical forests. The 1980s witnessed a short burst of publications (Huntley & Walker, 1982; Bourliere, 1983; Frost et al., 1986; Sarmiento, 1984; Tothill & Moss, 1985; Cole, 1986; Walker, 1987) partly stimulated by the RSSD programme (Responses of Savannas to Stress and Disturbance) of the Decade of the Tropics (IUBS/UNESCO) and the international DIVERSITAS Programme (IUBS/SCOPE/UNESCO). This productivity has tailed off in the 1990s though there have been a few related texts such as Long, Jones & Roberts, 1992; Furley, Proctor & Ratter, 1992 or Young & Solbrig, 1993 and a number of valuable regional publications. It is therefore particularly helpful to have an authoritative, wide-ranging and up to date text which goes some way to rectifying this deficiency—although in many ways it points out the considerable gaps in our comprehension of this varied and dynamic biome.

The book arises out of a conference held in Brasília on the role of biodiversity in the function of savanna ecosystems, sponsored by the International Union of Biological Sciences (IUBS), the Scientific Committee for Problems of the Environment (SCOPE) and the United Nations Educational, Scientific and Cultural Organisation (UNESCO). It is divided into two main parts: the first represents nine invited chapters which deal systematically with the theme of the conference and have a greater coherence than the second three chapters which are compilations of the issues broached at the meeting but written up later. The book is concluded by a short chapter which summarizes the major findings regarding the initial question of the meeting—whether biodiversity affects the functioning of savannas?

The first part of the book will form a valuable contribution for anyone concerned with the current ecological issues of savannas. The opening two chapters also provide a useful overview, which could act as an introduction for anyone starting off in this area. Solbrig summarizes what is known of the biodiversity through an initial set of definitions, categories of savanna, environmental controls (climate, geomorphology and soil), productivity, floristic and faunal diversity. The book's editors then present a review concerned with the determinants of savannas—plant available moisture (PAM), plant available nutrients (PAN), fire and herbivory. The remaining chapters present a varied set of topics which the editors presume to cover the theme. Medina tackles the subject of biodiversity and nutrient relations. He questions the assumptions that the degree of resource capture increases with the number of species per unit area and, secondly, that species composition and abundance affect nutrient availability over time and space (resulting in the well known patchiness of nutrient distribution). Sarmiento considers the important relationship between biodiversity and water relations and reviews floristic richness with particular emphasis on water stress and the role of PAM measurements. Aspects of grass invasions are examined by Baruch who shows how specific and structural biodiversity is drastically reduced by the accidental or deliberate introduction of African grasses in the neotropics. The controversial links between biodiversity and primary production are assessed by Bulla. He argues that (perhaps surprisingly at first) low productive, stress-driven communities and high production, competition-dominated communities have lower diversities than intermediate ones. He also raises the issue of burning, where fire elimination increases biomass which tends to lower species diversity. Fire is also the theme of Braithwaite's chapter. He reviews what is known about fire effects in northern Australia on plants, habitats, insects and vertebrates and suggests that indigenous (aboriginal) use of fire does increase habitat diversity by increasing patchiness. A different and little known theme is taken by Lewinsohn & Price in their discussion of herbivorous insects. Given the prominence of insects in the savannas and their role in grazing and decomposition, there is remarkably poor evidence on species diversity or detailed studies of food webs. The authors discuss how insect diversity could be related to ecosystem processes and the functional categories of insects for investigating these links. The final chapter in this part considers the theme of biodiversity and stability. Since it is extremely arguable whether savanna systems in any one place are in equilibrium, the nature of (in)stability—its type, intensity and extent—is clearly important.

The compilations which made up the second part of the book cover the themes of biodiversity related to (1) energy flow, water use and nutrient cycling, (2) fire and herbivory, and (3) ecosystem properties. These chapters have clearly been put together by several authors and are, at times, difficult to follow. However, they have the innovative idea of presenting hypotheses to take research further. These conceptual ideas offer many stimulating lines of investigation whilst at the same time revealing how little we know of the mechanisms underpinning savanna ecology, how species diversity affects these mechanisms and is in turn affected by them.

There is little doubt that the text provides a valuable addition to the literature. Inevitably with so many different authors there is a lack of consistency in the depth and in the range of examples. There is a tendency for overlap and indeed a degree of internal contradiction (in definitions, use of diversity indices etc.), but in a sense this is part of the debate and is not a weakness. The very varied reference lists give valuable insight into current research. There is an over-emphasis on the New World savannas and it is a pity that there is so little based on southern Africa, but otherwise the coverage is stimulating.

On reflection, the book highlights the achievements of research into savannas and also points to deficiencies in our knowledge, some of which need to be addressed urgently in the light of continued pressure on land. The achievements could be summarized as: a broad comparative understanding of the regional formations and of the specific problems associated with them; a fairly good picture of the vascular floras and higher plant diversity; a general idea of the environmental controls; an understanding of the role of fire—very detailed in some areas but sketchy in most others; and a generalized view of soil-plant relationships. However, the book illustrates the deficiencies in knowledge such as the lack of data on many important groups of savanna organisms, especially non-arthropod invertebrates, fungi and protists—indeed most microfauna and microflora. There is also a lack of understanding of spatial as well as temporal changes in biodiversity. As suggested earlier, there is a deficiency of data on key mechanisms affecting species diversity (both composition and structure), such as microbial effects on nutrient availabiity, the role of root exudates and root strategies, adaptations to fire and herbivory, and use and channelling of energy. The book gives many pointers to pressing research needs. Combined with other current work on the land use implications of this ecological evidence, we might be able to tackle the wider management issues with greater confidence.

P.A. FurleyDepartment of Geography,University of Edinburgh, U.K.

REFERENCES

Bourliere, F. (ed.) (1983) Tropical savannas. Ecosystems of the World 13. Elsevier, Amsterdam

Cole, M.M. (1986) The savannas: biogeography and geobotany. Academic Press, London

Furley, P.A., Proctor, J. & Ratter, J.A. (eds) (1992) Nature and dynamics of forest-savanna boundaries. Chapman & Hall, London

Frost, P.G.H., Menaut, J.C., Medina, A., Solbrig, O.T., Swift, M. & Walker, B. (1986) Responses of savannas to stress and disturbance. Biology International Special Issue 10. IUBS, Paris

Huntley, B.J. & Walker, B.H. (eds) (1982) Ecology of tropical savannas. Springer-Verlag, Berlin

Long, S.P., Jones, M.B. & Roberts, M.J. (eds) (1992) Primary productivity of grass ecosystems of the tropics and sub-tropics. Chapman & Hall, London

Sarmiento, G. (1984) The ecology of neotropical savannas. Harvard University Press, Cambridge

Tothill, J.C. & Mott, J.J. (eds) (1985) Ecology and management of the world's savannas. Australian Academy of Science, Canberra

Walker, B.H. (ed.) (1987) Determinants of tropical savannas. IRL Press, Oxford

Young, M.D. & Solbrig, O.T. (eds) (1993) The world's savannas: economic driving forces, ecological constraints and policy options for sustainable land use. MAB Series Volume 12. UNESCO, Paris & Parthenon Press

GLOBAL ETHICS: INTERCULTURAL HARMONY OR CULTURAL HEGEMONY?

Callicott, J.B. (1997) Earth's insights: a multicultural survey of ecological ethics from the Mediterranean basin to the Australian outback. University of California Press, Berkeley, California. xxiv+285 pp., index. Paperback: Price US$ 16.95. ISBN 0-520-08560-4.

Callicott's volume sets out to provide a model of environmental ethics which, he suggests, integrates but does not attempt to homogenize a wide range of ethical perspectives. A philosopher, Callicott stresses the need to avoid merely exporting western environmental ethics or importing those from a particular cultural tradition, suggesting that instead we should consider how a ‘network of ethics’ might be discovered in the array of ethical stances to be found around the world. He therefore embarks upon a ‘global tour’ of religious and cultural traditions, focusing upon the environmental value promulgated by each.

Drawing upon Leopold's seminal essay, ‘The Land Ethic’, Callicott defines environmental ethics as ‘limitations on human freedom of action in relationship to non-human natural entities and to nature as a whole’ (p.1). Ethics, he suggests, are ‘embedded in larger conceptual complexes—comprehensive worldviews— that more largely limit and inspire human behavior’ and exert ‘a real force upon practice’ (p. 5). Some examples of the practical application of ethics are provided in a final chapter (which might have been better placed here) in which Callicott considers the Land Stewardship project in the US, the Chipko movement in northern India and the Sri Lankan Sarvodaya movement (p. 234).

Although a vague concept of culture is implicit in Callicott's discussion, offering an obvious framework for comparing particular social and economic practices and cosmological beliefs, this theoretical potential is passed over. Instead, he suggests that cultural diversity may be integrated and a global level of ethics achieved through the prism of a ‘postmodern scientific worldview’ (p. 10).

Before enlarging upon this theme, he sets out upon an environmental ethics tour, beginning with various interpretations of Christian mythology. Here, he suggests, the ‘stewardship’ interpretation offers a model that is ‘both powerful and practicable’ (p. 24). A journey through Greco–Roman myth and philosophy, is followed by an exploration of Islamic visions of the relationship between humanity and nature. Callicott the considers concepts of Gaia, both as the ‘prehistoric, prepatriarchial’ worldview of the west, and in its modern re-incarnation as described by Leopold in the 1940s, eco-feminists in the 1970s and subsequently by James Lovelock.

The ethics tour then heads eastwards to consider Hinduism, which Callicott suggests was anti-environmentalist until reframed in the 1970s (for example by Ryali) to accommodate environmental concerns. Nevertheless, he suggests that its mysticism inspired Naess and contributed to the development of Deep Ecology. He then discusses how Jain precepts—the rejection of the material world—have been more able to accommodate environmental ethics. A comparison is made with Buddhism, and Callicott concludes that the non-material, ‘world denying’ themes within these eastern religions enables the development of a broader environmental ethic.

Callicott then turns to the East Asian philosophies, to consider Taoism, Confucianism and East Asian Buddhism, paying particular attention to Japanese relations with the environment. These philosophies, he maintains, are very worldly and harmonious with the ethics inherent in Deep Ecology. The discussion then moves to the ‘Far Western Environmental Ethics’ of Polynesia, New Zealand, North America and Australia. With particular reference to the ethos of Black Elk, these are presented as being centred upon a reverence for nature. South American groups are presented equally romantically, as ‘Stone Age peoples’ in ‘pristine condition’ before becoming ‘polluted with Western technologies, habits, and beliefs’ (p. 135). In Chapter 8, the Aboriginal Australians are similarly presented as exemplary in their environmental ethics, because they sanctify the land and, like the Polynesian and North American groups, regard their relationship with it as collective and inalienable. Only in African societies it seems, does Callicott find an absence of environmental ethics:Africa looms as a big blank spot on the world map of indigenous environmental ethics . . . (p. 158).

There are some obvious contradictions in this section (for instance, the San are described as placing human and non-human beings on an equal footing, which suggests a quite meaningful ethical stance), and the damning of Africa illustrates one of the major problems of the volume. In attempting a whistle-stop tour—a ‘global sample of traditional and indigenous environmental attitudes and values’ (p. 186), the outcome inevitably lacks ethnographic depth and accuracy. It may be that it is impossible to provide such brief ‘thumbnail’ sketches without caricaturing or romanticizing each group, but the end result suggests a somewhat ethnocentric set of assumptions about the worth of some cosmological schema, and considerable naivety about others.

Though Earth's insights is a brave attempt to compare different ethical perspectives, the final section is troubling: Callicott suggests that ‘for better or worse’, western scientific ideas are a ‘pervasive cognitive ether’ (p. 187). What we need, he says, is a ‘constructivist postmodern worldview’, a postmodern environmental ethic which respects diversity but also tries ‘to bring the intellectual elements of the earth's many indigenous cultural traditions into a complementary and concordant relationship with those of postmodern international science’ (p. 210). Thus, despite Callicott's earlier assurances, we end up with a model in which it seems that western science is still intended to provide the core theme for a globalized ethical framework. The many cultural groups resisting the hegemony of this ‘pervasive ether’ may consider their own insights about the earth to be more useful.

Veronica StrangDepartment of Anthropology,University of Wales, Lampeter, U.K.

REFERENCES

Leopold, A. (1949) A sand county almanac. Oxford University Press, Oxford.

Lovelock, J. (1979) Gaia: A new look at life on Earth. Oxford University Press, Oxford.

Naess, A. (1973) ‘The shallow and the deep, long-range ecology movement: a summary, Inquiry, 16, 95–100

Neihardt, J. (1961) Black Elk Speaks: being the life story of a holy man of the Oglala Souix. University of Nebraska Press, Lincoln.

Ryali, R. (1973) ‘Eastern-mystical perspectives on environment, Ethics for environment: three religious strategies (ed. by D. Stefferson, W. Herrscher and R. Cook. University of Wisconsin Press. pp. 47–48

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