Principles and Practices in Plant Ecology: Allelochemical Interactions. Inderjit, K.M.M. Dakshini and Chester L. Foy, eds., 1999. ISBN 0-8493-2116-6 (cloth US$ 129.95) 589 pp. CRC Press LLC, 2000 Corporate Blvd., N.W., Boca Raton, FL 33431—Researchers have spent much time determining how plants react to manufactured chemicals like pesticides and herbicides, but relatively less time examining how plants react to chemicals released by neighboring plants. This response to naturally produced chemicals is termed allelopathy. More strictly defined, allelopathy is an interaction between plant or microbial species involving chemical control — either beneficial or detrimental — of one organism by another (Rice 1974). In a few instances this chemical control is hard to miss. For example, black walnut's release of juglone clearly suppresses other plants growing under the tree. However, allelopathic effects are often not as strong, or can differ between locations and/or times. These different reactions usually occur because of variable environmental conditions, such as soil type or a stressful plant environment.
The 61 contributing authors present a global perspective on allelopathic research. Their main focus is to integrate facets of allelochemical production and action under different environmental conditions. Other themes of the book are discussing the variable environmental roles of allelochemicals, and addressing allelopathic interactions in different communities. For example, several chapters address secondary chemicals (including phenolics, flavonoids, alkaloids, saponins and coumarins) as defenses against herbivores and microbes, in addition to their allelopathic action. One chapter also discusses the role of plant polyphenols on nutrient cycling. This book also covers some specific interactions including allelopathy in plankton, bacteria, and in benthic and littoral regions.
This book would be an important addition to any library, especially for those interested in how secondary chemicals affect the environment. It would also make a great text for a graduate level course. Not only are the chapters clear and easy to follow, but their authors often include recommendations for further study, and areas needing in-depth investigation. Additionally, the beginning section of the book also includes seven chapters on basic project design, making the study relevant to field conditions, common flaws in allelopathic research, and some basic chemical analysis. Besides discussing methodologies, it also includes chapters on a fascinating topic — allelopathic interactions between different species' pollen at the stigmatic surface. If an organism attempts to control the numbers and kinds of other species growing in the same area, why not stop competition before this other species ever has a chance to grow? The book finishes with four chapters on aspects of applied allelopathy, including potential plant and microbial-produced herbicides.
One shortcoming is common in published allelopathic reports — there was very little coverage on how allelochemicals benefit their neighbor's growth. Fertilization effects commonly occur, and are allelopathic by definition, but seem to have been swept under the ecological rug. Laudably, the book does include a chapter that claims that alleged allelochemicals could not be phytotoxic under natural conditions. This lack of toxicity could not only be due to microbial action, but to soil's physical factors, including chemical absorption to the soil surface, and forming complexes with humus. This reinforces the need for field studies to determine possible allelopathic effects in addition to laboratory data.
Reading this book makes it clear — allelopathy may occur in all environments, and should be considered as a part of community interactions. We need to consider that allelochemicals may have less drastic effects than simply killing neighbors, that interactions change with plant stress, and that not all plant species react similarly to the same chemical.—Michelle A. Briggs, Department of Biology, Lycoming College, Williamsport, PA 17701
Ecological Vignettes: Ecological Approaches to Dealing with Human Predicaments. Eugene Odum. 1998. ISBN 90-5702-522-1 (paper US$ 21.95)269 pp. Harwood Academic Publishers, The Netherlands.—Whether you subscribe to 31 December 1999 or 31 December 2000 as the last day of the millennium, or count years by the Chinese calendar, it is clear to see that a new era in human history is fast upon us. Our population has grown rapidly, and our demands upon and insults to the ecosphere have grown even faster. One does not have to be a visionary to see that the next thousand years are unlikely to support another 100-fold increase in the human population. Nor does one have to be a prophet to foretell that we will be faced with increasingly difficult and urgent environmental problems as we approach the earth's carrying capacity. What does require vision and a prophetic voice is conceiving and proclaiming a radical solution to these problems. Eugene Odum attempts such a solution in this slim volume which aims to "improve environmental literacy at all levels - kindergarten through senior citizenry." Education, specifically learning the "Wisdom of Nature" that ecological studies have revealed, provides a starting point for an educated populace to enact "ecological approaches to dealing with human predicaments."
This slim volume is designed to serve as a primer for environmental literacy, as suitable for students as senior citizens. Odum's approach to this task is two-pronged: first, convey basic ecological principles through the use of short vignettes and cartoons; and second, provoke thought and discussion about the application of those principles to our human predicaments through a collection of essays. The first eight chapters present a series of 21 vignettes which clearly and concisely illustrate the lessons we may learn from ecology about growth, energy, organization, change, behavior and diversity, and also those we don't learn from nature, but may learn from close observation of human behavior. The last 80% of the text is a collection of 26 short essays, 22 of which are culled from Eugene Odum's lifetime passion for and production of accessible writing about ecology and the connections between science and society. The remainder were written by Howard T. Odum, William E. Odum, and William R. Catton, Jr.
The greatest strengths of this volume are in the brevity and clarity to which it distills our ecological lessons, and in the challengingly counter-cultural currents that run through the essays. These strengths are inseparable. Odum's ecological approaches deduced from the "Wisdom of Nature" call us from the madness of the masses to the consciousness of our connectedness to creation. In contrast to our cultural enshrinement of growth as the economic panacea ("bigger is better!"), and the twentieth century's dismal history of violent military reactions to human problems, consider the lessons of ecology that growth must be limited, and that cooperation is preferable to conflict.
The brevity of the first section of this book (58 generously illustrated pages to convey the 21 vignettes and their explanations) is also one of its greatest weaknesses. At times the explanation or illustration of the ecological lesson at hand is so brief as to be cryptic. It is rather like being taught in parables. This could be a problem, especially for those to whom these ecological ideas are news. This shortfall is largely overcome, however, by the content of the following 187 pages of essays, which parallels that of the preceding vignettes. Although the essays were written over a 30-year period, very little of the material is outdated or lacking in pertinence.
In conclusion, I have found Ecological Vignettes to be a useful and fruitful stimulus for discussion and learning in the general education science courses that I teach. I heartily recommend it for libraries at all levels, as well as for use in those courses where scientists have the greatest opportunity to exert a positive influence on society by attempting to enlighten every student who comes through the doors of higher education.—Jonathan Frye, McPherson College, McPherson, KS
The Terrestrial Biosphere and Global Change: Implications for Natural and Managed Ecosystems. Synthesis Volume. B. Walker, W. Steffen, J. Canadell, J. Ingram, eds. 1999. ISBN 0-521-62480-0 (paper US$49.95) 439pp. Cambridge University Press, 40 West 20th St., New York NY 10011-4211
The Terrestrial Biosphere and Global Change: Implications for Natural and Managed Ecosystems. Synthesis Volume. B. Walker, W. Steffen, J. Canadell, J. Ingram, eds. 1999. ISBN 0-521-62480-0 (paper US$49.95) 439pp. Cambridge University Press, 40 West 20th St., New York NY 10011-4211—When the clock will be ticking the first seconds of the year 2000 there will be a little more than 6 billion humans living on earth. Probabilistic projections indicate that there is a 95% probability that the population will lie between 10.0 and 12.0 billion in 2050, and between 15.7 and 17.3 billion in 2100. This is how the editors set forth the challenging nature of global change in the introductory chapter. This book is a synthesis of the current understanding of global change interactions with terrestrial ecosystems. Forty scientists contributed to this highly technical synthetic work on the implications of global change upon the natural and managed ecosystems. In the twelve chapters covering five major thematic areas: ecosystem physiology; ecosystem structure and composition; terrestrial production systems; global biogeochemistry and ecological biodiversity, the international research effort in the Global Change and Terrestrial Ecosystems Core Project (GCTE) of the International Geosphere Biosphere Program (IGBP) has set an essential milestone.
How do we determine the impact of humans upon ecosystems ? The imprint that humans have on ecosystems is resolved by the so called ÎPLOT1 equation; a function of Population size, lifestyle, Organization and Technology. Climate change is the most publicized component of global change but land use/ cover conversions and atmospheric alterations are equally fundamental to this interdisciplinary environmental issue. The science of ecosystem study started in the 1960's- 1970's with the inception of the International Biologic Program (IBP). The authors caution that ecosystem study is difficult due the large scale processes involved, much larger than the typical experimental plot of a few hectares. Some of the natural processes require decades to centuries for completion rendering replication and monitoring arduous.
The inherent complexity of ecosystems result in a large number of variables which affect complex energy fluxes. Though, some on-going successful manipulative experiments in the fields of elevated CO2, nutrient/ water interactions are presented. Despite some of the inherent limitations of ecosystem research, GCTE has been successfully integrating the large and complex international body of knowledge using networking as a fundamental communication strategy. The use of transects and scales has been another beneficial approach taken by the IGBP as a tool for global change research. The basic transect design is outlined in the fourth chapter, focusing on the North East China Transect (NECT). The important role of remote sensing in transect research is described. Finally, the chapter focuses on the use of transects as tools for synthesis and research integration. The next two chapters center on ecosystem modeling both in terms of data needs and applications. However, in the context of this book a full catalogue of available datasets is not provided.
Global change ecological modeling addresses many basic issues of ecosystem structure and functioning where the critical factor of scale is fundamental to the computations and outputs. A model review aimed at managed ecosystems such as crops, grasslands and forests is provided. Then the authors present biogeochemical models describing fluxes of water, carbon and nutrients between the vegetation and the atmosphere ignoring issues such as changes in community structure and composition dedicated to its own section. This modeling discussion ends with the presentation of model-based attempts to unify structural and functional dynamics of ecosystems. The seventh chapter summarizes the research status on the potential impacts of environmental change upon the physiology of ecosystems taking into consideration long term hydrological and biogeochemical feedbacks. The chapter examines the environmental factors that are predicted to change in the coming decades to a century such as: atmospheric CO2, temperature, water availability, N deposition, UV-B and tropospheric ozone. Major emphasis is placed on atmospheric CO2.
Various models are also presented to show the complex nature of the interactions among multiple global change drivers, which can lead to feedbacks, both positive and negative, on ecosystem responses. Changes in ecosystem composition and structure are then discussed at three levels of organization: vegetation patches, landscapes, and entire regions of the globe itself. This is an excellent synopsis on the topic, highly recommended to botanists. Eight color pages (most of the book is printed in black and white) of modeling outputs are presented on regional, national and global scales. Global change effects upon managed ecosystems is outlined in chapter nine. The central theme of the tenth chapter is the global carbon cycle. The conceptual model applied in this chapter is that the carbon cycle cannot be viewed outside of the context of the other biogeochemical (chemistry of the earth's surface) cycles that are closely coupled to it. A schematic view of the linkages of the carbon, nitrogen, phosphorus and water cycles is presented. The last two chapters examine how global change affects biodiversity and ecological complexity. The authors "look into the future" to develop probable biodiversity scenarios. These scenarios are based on simulation models of changes in land use, climate, and atmospheric composition. The final chapter synthesizes the findings of the GCTE program in five major global change issues: (i) terrestrial carbon cycle; (ii) interaction of ecosystem structure and functioning; (iii) vegetation dynamics; (iv) impacts on production systems; and (v) effects on ecological complexity. In terms of conclusion eight emerging questions and challenges are discussed.
I wish chapter summaries were consistently presented. I also encourage the use of more case studies. I support the creation of a simpler, condensed version of this book, that might be distributed to school libraries. Educating the next generation early, on the issue of global change is a duty of the scientific community. I surely hope this essential work will be read by world political leaders, so that policies implementing sustainable use of natural resources will be developed. We all depend on our natural environment for the bulk of our food and fiber, for the provision of clean air and water, for some of the processing and storage of our waste material, ultimately for our physical and spiritual well being. Aside from this anthropocentric perspective, terrestrial ecosystems are the home of million other species which hold equal share to the enjoyment of our planet's natural environments. A challenge ahead is bridging the scientific body of knowledge applied to global change with the creation of policies implemented to protect the global biological communities.—Laurent M. Meillier, U.C. Santa Barbara, Department of Geological Sciences, Santa Barbara, CA.
Ecology of Sonoran Desert Plants and Plant Communities Robichaux, Robert H., ed., 1999. ISBN 0-8165-1869-6 (cloth US$45) 312 pp. The University of Arizona Press, 1230 N. Park St., Suite 102, Tucson AZ 85719
Ecology of Sonoran Desert Plants and Plant Communities Robichaux, Robert H., ed., 1999. ISBN 0-8165-1869-6 (cloth US$45) 312 pp. The University of Arizona Press, 1230 N. Park St., Suite 102, Tucson AZ 85719—This is an intriguing book dealing with various aspects of Sonoran desert plants and plant communities. The eight chapters are far ranging in their subjects, and this broadness might be surprising on a first glance. However, the introduction tells the reason: the book was produced on the occasion of the 95th anniversary of the Desert Research Laboratory, located near Tucson, Arizona, and should provide a sample of the research pursued in this region and at this institution. More details on the Desert Laboratory can be found in Bowers (1990).
Each of the chapters is a review or summary of research conducted by the contributors. They are well and readable written, supplemented by excellent illustrations and written in such a way that specialists from other fields can understand them. One name appears throughout the first half of the book: Forrest Shreve, who joined the staff of the Desert Laboratory in 1908, carried out extensive investigations on the Sonoran flora and is the author of "Vegetation of the Sonoran Desert" (Shreve 1951).
The first three chapters deal with patterns of vegetation and plant communities at the landscape level. In the first chapter (S. P. McLaughlin and J. E. Bowers) the affinities and diversity of the flora are explored. It reviews past and current phytogeographic treatments of the Sonoran floristic province, and provides numerical floristic analyses based on a large number of local floras in order to relate species diversity to environmental variation and further define the floristic boundaries between the subdivisions. Unfortunately, alien species are not considered in their analyses, although exotics also have reached the Sonoran desert region. The next chapter (A. Burquez, A. Mart’nez-Yr’zar, R. S. Felger, and D. Yetman) reviews the relationships between the physical environment, habitat diversity, and vegetation structure. Although somewhat redundant to the previous chapter, it gives a nice description of the vegetation types encountered in the Sonoran region, and explores how microhabitat variation translates into changes of species diversity. J. R. McAuliffe (chapter 3) gives an overview on the landscape complexity and ecological diversity of the Sonoran desert. The chapter extensively discusses how important soil types and water availability are in shaping vegetation structure and its specific composition. Very intriguing is the relationship between the age of alluvial deposits and the size and age of long-lived perennials that colonized these. Creosote bush (Larrea tridendata) clones can be several thousands of years old, and younger alluvial deposits bear younger (smaller) clones. This illustrates that the sizes of these plants and their population structure must be linked to geological changes in the landscape.
Chapter four (D. L. Venable and C. E. Pake) brings the scale down to that of annual species. Annuals make about half of the species in local Sonoran floras and are important since their fluctuations from year to year determine the population dynamics and composition of seed predators. The chapter presents results on the population dynamics of 30 annuals over a period of 15 years and explores the relationship between seed germination, fecundity, population size, and dispersal to environmental variation. The authors discuss to what extent desert annuals represent a system in which temporal variation promotes species coexistence.
The next chapter (P. S. Nobel and M. E. Loik) is again highly contrasting to the previous one. Form and function of cacti shows great variability in the Sonoran desert, and the authors investigated how the form of a cactus influences its interaction with the environment by means of ecophysiological measurements in roots and stems. The role of nurse plants as regeneration niches for cacti is discussed. Chapter six (W. J. Etges, W. R. Johnson, G. A. Duncan, G. Huckins, and W. B. Heed) deals with plant-animal interactions. The ecological genetics of two cactophilic pomace flies (Drosphila pacheaand D. mojavensis) were studied with the aim to compare chromosomal variability in relation to the distribution of the host cacti used for feeding and breeding. The main findings are that the karyotypic variation of the flies match the distribution of the host cacti. Thus, the authors conclude that the (climatic) forces that shaped the vegetational subdivisions and the distribution of host plants in the Sonoran desert also influenced the genetic variation in many insect species.
Quite a different topic is covered in the next chapter (L. L. Jackson and P. W. Comus). The reader learns how agricultural development since European colonization (and before) influenced the natural vegetation of the Sonoran desert valley. The authors virtually took every available piece of information to reconstruct the spread of agricultural development in this region since 1885. Two technologies had major effects on the hydrology and vegetation: the big dam and the deep pump. The chapter provides impressive data on the water pumped and on the increase of abandoned farm land as a result of groundwater decline. The authors also studied the natural vegetation remnants in this area and discuss the consequences for ecosystem recovery. Their conclusion is that a recovery will be very limited considering the profound changes that happened. Finally, the last chapter (P. S. Martin) provides insights into the deep history of the Sonoran desert. Martin demonstrates how climatic changes during the last 40 000 years, and ancient cultures had a major influence on the present biota.
Thus, the chapters deal with all scales from landscape to population, and are far beyond pure ecology. This must be accounted for in the title of the book. An important message of the book is that understanding the ecology of plants and plant communities of the Sonoran desert requires studies at all scales in time and space.
Since the articles are strongly linked to the Desert Laboratory, the reader might wish to learn more about it. A possibility would be to include a small chapter on the past and present research activities and the major publications that resulted from this institution. Such informations could also be included in the introduction. Some parts of the first three chapters appear somewhat redundant as similar questions are addressed. As an ecologist working on invasive species, I missed this issue - but as stated in the introduction, there are more themes than can be included in such a book. Since the last two chapters are strongly related to geology and landscape patterns, they probably would be better placed after the third chapter.
Despite these rather small critiques, the volume provides a wealth of information including the citation of many older works. It is the broadness mentioned at the beginning that makes the book highly valuable to anyone studying desert ecosystems and seeking a deeper understanding of the factors and mechanisms that shape the plant communities of the Sonoran Desert.—Ewald Weber, Institute for Environmental Studies, University of Zurich, Zurich, Switzerland