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Theoretical Ecology Meets Agroecology: Towards an Ecological Approach to Agroecosystems Theoretical Approaches to Biological Control by Bradford A. Hawkins; Howard Vernon Cornell Review by: John Vandermeer Ecology, Vol. 81, No. 6 (Jun., 2000), pp. 1758-1759 Published by: Ecological Society of America Stable URL: http://www.jstor.org/stable/177324 . Accessed: 08/05/2014 19:40 Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at . http://www.jstor.org/page/info/about/policies/terms.jsp . JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. . Ecological Society of America is collaborating with JSTOR to digitize, preserve and extend access to Ecology. http://www.jstor.org This content downloaded from 169.229.32.137 on Thu, 8 May 2014 19:40:59 PM All use subject to JSTOR Terms and Conditions

Theoretical Ecology Meets Agroecology: Towards an Ecological Approach to Agroecosystems

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Page 1: Theoretical Ecology Meets Agroecology: Towards an Ecological Approach to Agroecosystems

Theoretical Ecology Meets Agroecology: Towards an Ecological Approach to AgroecosystemsTheoretical Approaches to Biological Control by Bradford A. Hawkins; Howard Vernon CornellReview by: John VandermeerEcology, Vol. 81, No. 6 (Jun., 2000), pp. 1758-1759Published by: Ecological Society of AmericaStable URL: http://www.jstor.org/stable/177324 .

Accessed: 08/05/2014 19:40

Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at .http://www.jstor.org/page/info/about/policies/terms.jsp

.JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range ofcontent in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new formsof scholarship. For more information about JSTOR, please contact [email protected].

.

Ecological Society of America is collaborating with JSTOR to digitize, preserve and extend access to Ecology.

http://www.jstor.org

This content downloaded from 169.229.32.137 on Thu, 8 May 2014 19:40:59 PMAll use subject to JSTOR Terms and Conditions

Page 2: Theoretical Ecology Meets Agroecology: Towards an Ecological Approach to Agroecosystems

Ecology, Vol. 81, No. 6 Ecology, Vol. 81, No. 6

Hanski's incidence function model to a variety of species (especially butterflies) and situations, including "classical" metapopulations and those with transient dynamics or mul- tiple equilibria. The examples make a compelling case for wider application of his approach.

Readers of Metapopulation ecology who are not inclined to work on butterflies may feel left behind. They should also feel challenged to more rigorously apply ideas from meta-

population theory to better understand the biology of their organisms or communities (and vice-versa). Whether or not

you've read other recent volumes in the field, Metapopulation

Hanski's incidence function model to a variety of species (especially butterflies) and situations, including "classical" metapopulations and those with transient dynamics or mul- tiple equilibria. The examples make a compelling case for wider application of his approach.

Readers of Metapopulation ecology who are not inclined to work on butterflies may feel left behind. They should also feel challenged to more rigorously apply ideas from meta-

population theory to better understand the biology of their organisms or communities (and vice-versa). Whether or not

you've read other recent volumes in the field, Metapopulation

ecology will provide a fresh and synthetic view of the rich insight that metapopulation theory can offer. This book rep- resents an important milestone by one of the undisputed gurus of the field, and belongs not on the shelf, but in the hands of any practicing or prospective metapopulation biologist.

JASON B. DUNHAM

University of Nevada, Reno Biological Resources Research Center Department of Biology Reno, Nevada 89577

ecology will provide a fresh and synthetic view of the rich insight that metapopulation theory can offer. This book rep- resents an important milestone by one of the undisputed gurus of the field, and belongs not on the shelf, but in the hands of any practicing or prospective metapopulation biologist.

JASON B. DUNHAM

University of Nevada, Reno Biological Resources Research Center Department of Biology Reno, Nevada 89577

Ecology, 81(6), 2000, pp. 1758-1759 ? 2000 by the Ecological Society of America

THEORETICAL ECOLOGY MEETS AGROECOLOGY: TOWARDS AN ECOLOGICAL APPROACH TO AGROECOSYSTEMS

Ecology, 81(6), 2000, pp. 1758-1759 ? 2000 by the Ecological Society of America

THEORETICAL ECOLOGY MEETS AGROECOLOGY: TOWARDS AN ECOLOGICAL APPROACH TO AGROECOSYSTEMS

Hawkins, Bradford A., and Howard Vernon Cornell, editors. 1999. Theoretical approaches to biological control. Cam- bridge University Press, New York, xii + 412 p. $105.00, ISBN: 0-521-57283-5.

Hawkins, Bradford A., and Howard Vernon Cornell, editors. 1999. Theoretical approaches to biological control. Cam- bridge University Press, New York, xii + 412 p. $105.00, ISBN: 0-521-57283-5.

The modern agroecosystem emerged as a hybrid of pro- duction traditions extending back many generations and pro- duction technologies born of the nineteenth century. Its ma-

turity came only after World War II, when chemicals devel-

oped in war research found a ready market on farms trying to deal with age-old problems of soil fertility and pest control. The resulting system, which we today call conventional, is a model of productivity, causing marginal farmlands to be pro- ductive and enabling good farmlands to be even more pro- ductive. But, as is now acknowledged by most observers, this

cornucopian production has come with a cost-contamination of wells and waterways, potentially carcinogenic residues in food, non-sustainable use of the resources on which the sys- tem depends, loss of biodiversity, and so forth. Indeed, much of the basis of the environmental movement stimulated by Rachael Carson's Silent spring had to do with problems gen- erated by the conventional agroecosystem.

Developing in parallel with the conventional system was an alternative-actually a collection of alternatives, but re- ferred to here simply as the alternative for convenience. Rath- er than rely on a simplistic notion of Liebig's law of the minimum to indicate which readily soluble ions to introduce into the soil, the alternative emphasized wise stewardship of soil organic matter as much for good plant nutrition as for

good soil physical structure. Rather than rely on a specific chemical poison to kill a pest, the alternative emphasized management practices that would minimize emergence of

pests in the first place. This alternative agriculture in many ways looks like the agriculture done before the industrial revolution, but in other ways goes beyond. Today it stands as a minor component, filling a so-called "niche" market, in the multibillion dollar agriculture business that still dominates much of world trade.

Adherents of the alternative model, have long promoted

The modern agroecosystem emerged as a hybrid of pro- duction traditions extending back many generations and pro- duction technologies born of the nineteenth century. Its ma-

turity came only after World War II, when chemicals devel-

oped in war research found a ready market on farms trying to deal with age-old problems of soil fertility and pest control. The resulting system, which we today call conventional, is a model of productivity, causing marginal farmlands to be pro- ductive and enabling good farmlands to be even more pro- ductive. But, as is now acknowledged by most observers, this

cornucopian production has come with a cost-contamination of wells and waterways, potentially carcinogenic residues in food, non-sustainable use of the resources on which the sys- tem depends, loss of biodiversity, and so forth. Indeed, much of the basis of the environmental movement stimulated by Rachael Carson's Silent spring had to do with problems gen- erated by the conventional agroecosystem.

Developing in parallel with the conventional system was an alternative-actually a collection of alternatives, but re- ferred to here simply as the alternative for convenience. Rath- er than rely on a simplistic notion of Liebig's law of the minimum to indicate which readily soluble ions to introduce into the soil, the alternative emphasized wise stewardship of soil organic matter as much for good plant nutrition as for

good soil physical structure. Rather than rely on a specific chemical poison to kill a pest, the alternative emphasized management practices that would minimize emergence of

pests in the first place. This alternative agriculture in many ways looks like the agriculture done before the industrial revolution, but in other ways goes beyond. Today it stands as a minor component, filling a so-called "niche" market, in the multibillion dollar agriculture business that still dominates much of world trade.

Adherents of the alternative model, have long promoted

the idea that agroecosystem development should be based on sound ecological principles and have suggested that much of what is wrong with the conventional system stems from ig- norance of those principles, either purposefully or through naivetd. Ecological principles indeed are unavoidably in- volved in agricultural development. Consequently the science of ecology ought to be the science behind the engineering of

ecosystems to become agroecosystems. Currently it is not. It is obvious to all concerned that the agroecosystem is an eco-

system in all the traditional senses of that word, and that it thus must conform to the rules of ecosystems as much as any other. Yet the study of agroecosystems from this point of view remains marginal in both the discipline of ecology and the various disciplines normally emphasized in conventional ag- riculture research. This is unfortunate for the future of the

planet. If ecology is to become to agriculture what physics is to mechanical engineering (as many in the alternative movement propose), ecologists must pursue the application of their science to agricultural problems and must allow ag- ricultural problems to be part of the determinant of where the science should to be moving.

In this context, "Theoretical approaches to biological con- trol" by Brad Hawkins and Howard Cornell is more than

just another book about ecological theory or the ecology of a particular management problem. It is a magnificent example of just the sort of synthesis that is needed to promote the alternative system and, more importantly, stands as an ex-

ample for the way in which this synthesis can come about. In 21 chapters, this book shows how fundamental principles of theoretical ecology can be brought to bear on this real

problem for the alternative movement and, perhaps more im-

portantly, illustrates how focusing on a real world problem can motivate the development of interesting ecological the-

ory. The chapters are grouped into five main themes ("Biolog-

ical control theory: past and present"; "Ecological consid- erations"; "Spatial considerations"; "Genetic/evolutionary considerations"; "Microbes and pathogens") and the editors

provide excellent brief summaries of all chapters at the be-

ginning of each of the five sections. While the first section

the idea that agroecosystem development should be based on sound ecological principles and have suggested that much of what is wrong with the conventional system stems from ig- norance of those principles, either purposefully or through naivetd. Ecological principles indeed are unavoidably in- volved in agricultural development. Consequently the science of ecology ought to be the science behind the engineering of

ecosystems to become agroecosystems. Currently it is not. It is obvious to all concerned that the agroecosystem is an eco-

system in all the traditional senses of that word, and that it thus must conform to the rules of ecosystems as much as any other. Yet the study of agroecosystems from this point of view remains marginal in both the discipline of ecology and the various disciplines normally emphasized in conventional ag- riculture research. This is unfortunate for the future of the

planet. If ecology is to become to agriculture what physics is to mechanical engineering (as many in the alternative movement propose), ecologists must pursue the application of their science to agricultural problems and must allow ag- ricultural problems to be part of the determinant of where the science should to be moving.

In this context, "Theoretical approaches to biological con- trol" by Brad Hawkins and Howard Cornell is more than

just another book about ecological theory or the ecology of a particular management problem. It is a magnificent example of just the sort of synthesis that is needed to promote the alternative system and, more importantly, stands as an ex-

ample for the way in which this synthesis can come about. In 21 chapters, this book shows how fundamental principles of theoretical ecology can be brought to bear on this real

problem for the alternative movement and, perhaps more im-

portantly, illustrates how focusing on a real world problem can motivate the development of interesting ecological the-

ory. The chapters are grouped into five main themes ("Biolog-

ical control theory: past and present"; "Ecological consid- erations"; "Spatial considerations"; "Genetic/evolutionary considerations"; "Microbes and pathogens") and the editors

provide excellent brief summaries of all chapters at the be-

ginning of each of the five sections. While the first section

1758 1758 BOOK REVIEWS BOOK REVIEWS

This content downloaded from 169.229.32.137 on Thu, 8 May 2014 19:40:59 PMAll use subject to JSTOR Terms and Conditions

Page 3: Theoretical Ecology Meets Agroecology: Towards an Ecological Approach to Agroecosystems

BOOK REVIEWS BOOK REVIEWS

is largely historical review, the rest of the chapters are reports on original work, summaries of particular themes, or presen- tations of work on very particular systems. Each and every chapters contains something of interest to both ecologist and biological control practitioner.

Especially interesting are three review-like chapters, "Re- cent developments in theory for biological control of insect pests by parasitoids" by Briggs, Murdoch, and Nisbet, "Mod- els in biological control: a field guide" by Barlow, and "The dynamics of insect-pathogen interactions" by Godfray and Briggs. Barlow and colleagues summarize six distinct struc- tured models of insect/parasitoid interactions with major in- sights for biological control. It is an excellent example of how general ecological theory can provide important quali- tative insights to a practical problem. Briggs summarizes 50

published models of biological control from the past 20 years, and does an admirable job of finding generalization from a remarkable diversity of modeling approaches. Godfray and

Briggs actually break significant new ground, since the ques- tion of pathogens in biological control is relatively new for theoretical ecology. Beginning with the Anderson/May model of infectious diseases, they elaborate not only on the theory itself but on the underlying biology and how theory needs to be modified to account for the particular exigencies of bio- logical control.

The range of subjects covered is large. From the use of native natural enemy generalists to the consequences of three trophic level dynamics, from outbreaks to stability theory, from spatial considerations to evolutionary considerations, the collection embraces an impressive array of subject mater. Yet I doubt anyone will charge that superficiality accompanies the decision to cast a broad net. For the most part each chapter could stand on its own as a solid contribution to a professional peer-reviewed journal.

is largely historical review, the rest of the chapters are reports on original work, summaries of particular themes, or presen- tations of work on very particular systems. Each and every chapters contains something of interest to both ecologist and biological control practitioner.

Especially interesting are three review-like chapters, "Re- cent developments in theory for biological control of insect pests by parasitoids" by Briggs, Murdoch, and Nisbet, "Mod- els in biological control: a field guide" by Barlow, and "The dynamics of insect-pathogen interactions" by Godfray and Briggs. Barlow and colleagues summarize six distinct struc- tured models of insect/parasitoid interactions with major in- sights for biological control. It is an excellent example of how general ecological theory can provide important quali- tative insights to a practical problem. Briggs summarizes 50

published models of biological control from the past 20 years, and does an admirable job of finding generalization from a remarkable diversity of modeling approaches. Godfray and

Briggs actually break significant new ground, since the ques- tion of pathogens in biological control is relatively new for theoretical ecology. Beginning with the Anderson/May model of infectious diseases, they elaborate not only on the theory itself but on the underlying biology and how theory needs to be modified to account for the particular exigencies of bio- logical control.

The range of subjects covered is large. From the use of native natural enemy generalists to the consequences of three trophic level dynamics, from outbreaks to stability theory, from spatial considerations to evolutionary considerations, the collection embraces an impressive array of subject mater. Yet I doubt anyone will charge that superficiality accompanies the decision to cast a broad net. For the most part each chapter could stand on its own as a solid contribution to a professional peer-reviewed journal.

The book does not shy away from some of the more com- plicated problems involved in theoretical applications to eco- logical problems. Some of the well-known eccentricities re-

cently emerging from non-linear dynamics (such as chaotic trajectories, multiple attractors, and the structure of basins of attraction) are dealt with explicitly. The temptation to reach for the large supposedly holistic systems models so popular in the 1960s is largely resisted by most of the authors, and is even a danger explicitly cited by several of them. Barlow, for example, elegantly summarizes the issue as "[models in bio control] are offering concrete predictions at a useful level, and ... have outgrown the initial temptation offered by com- puter simulation technology, to develop unnecessary and con-

fusing complexity. This is one of the every-present dangers for specific models, just as that for strategic models is to forget that the goal is to understand, not the behavior of models, but the behavior of nature."

For such a large collection one normally expects a great deal of variability in quality. However the editors somehow

managed to squeeze out the best of each contributor. Each and every chapter is well written, well referenced and timely. Indeed the book is a model of how theoretical work should be focused on practical problems. If ecology is to be the scientific basis of the new agriculture, this book may turn out to be the first applied engineering text. I only hope others will take it as inspiration to deal with the myriad of other

problems facing the movement for a new, more sustainable

agroecology.

JOHN VANDERMEER

University of Michigan Department of Biology Ann Arbor, Michigan 48109

The book does not shy away from some of the more com- plicated problems involved in theoretical applications to eco- logical problems. Some of the well-known eccentricities re-

cently emerging from non-linear dynamics (such as chaotic trajectories, multiple attractors, and the structure of basins of attraction) are dealt with explicitly. The temptation to reach for the large supposedly holistic systems models so popular in the 1960s is largely resisted by most of the authors, and is even a danger explicitly cited by several of them. Barlow, for example, elegantly summarizes the issue as "[models in bio control] are offering concrete predictions at a useful level, and ... have outgrown the initial temptation offered by com- puter simulation technology, to develop unnecessary and con-

fusing complexity. This is one of the every-present dangers for specific models, just as that for strategic models is to forget that the goal is to understand, not the behavior of models, but the behavior of nature."

For such a large collection one normally expects a great deal of variability in quality. However the editors somehow

managed to squeeze out the best of each contributor. Each and every chapter is well written, well referenced and timely. Indeed the book is a model of how theoretical work should be focused on practical problems. If ecology is to be the scientific basis of the new agriculture, this book may turn out to be the first applied engineering text. I only hope others will take it as inspiration to deal with the myriad of other

problems facing the movement for a new, more sustainable

agroecology.

JOHN VANDERMEER

University of Michigan Department of Biology Ann Arbor, Michigan 48109

Ecology, 81(6), 2000, pp. 1759-1760 ? 2000 by the Ecological Society of America

STATE-DEPENDENT MODELS AND BEHAVIOR

Ecology, 81(6), 2000, pp. 1759-1760 ? 2000 by the Ecological Society of America

STATE-DEPENDENT MODELS AND BEHAVIOR

Houston, Alasdair, I. and John M. McNamara. 1999. Models of adaptive behaviour. Cambridge University Press, New York. ix + 378 p. $80.00 (cloth), ISBN: 0-521-38480-X; $34.95 (paper), ISBN: 0-521-65539-0.

Houston, Alasdair, I. and John M. McNamara. 1999. Models of adaptive behaviour. Cambridge University Press, New York. ix + 378 p. $80.00 (cloth), ISBN: 0-521-38480-X; $34.95 (paper), ISBN: 0-521-65539-0.

The focus of this book is the use of state-dependent models to explain the evolution of behavior, which Houston and Mc- Namara define in a fairly liberal sense to include such life

history phenomena as delayed seed germination. However, most of the models are concerned with what is more generally regarded as behavior, such as foraging. The book is an ex-

position of a particular analytical/numerical approach to state-

dependent modeling. Houston and McNamara attempt to demonstrate that their approach is general by considering its

utility in understanding such diverse phenomena as risk-sen- sitive foraging and delayed germination.

The problem in the analysis of state-dependent strategies

The focus of this book is the use of state-dependent models to explain the evolution of behavior, which Houston and Mc- Namara define in a fairly liberal sense to include such life

history phenomena as delayed seed germination. However, most of the models are concerned with what is more generally regarded as behavior, such as foraging. The book is an ex-

position of a particular analytical/numerical approach to state-

dependent modeling. Houston and McNamara attempt to demonstrate that their approach is general by considering its

utility in understanding such diverse phenomena as risk-sen- sitive foraging and delayed germination.

The problem in the analysis of state-dependent strategies

is that, because of the exponential increase in possible tra-

jectories, forward projection of actions is not generally a viable method of analysis: the alternate is to start at some time t+ 1 and project backwards. This process is called dy- namic programming and has become very popular with be- havioral ecologists, particularly after the publication of Man-

gel and Clark's Dynamic modeling in behavioral ecology (Mangel, Marc, and Colin W. Clark. 1988. Princeton Uni-

versity Press, Princeton, New Jersey). Houston and McNa- mara's book is not meant to replace or compete with this book; rather it extends it by showing the many problems that can be tackled using dynamic programming.

The first two chapters introduce the general problem and the proposed approach. These introductory chapters are a lucid overview of the method developed throughout the rest of the book. The authors take it for granted that a state-

dependent approach is desirable. While I agree with them , it would have been nice to be given some specific examples

is that, because of the exponential increase in possible tra-

jectories, forward projection of actions is not generally a viable method of analysis: the alternate is to start at some time t+ 1 and project backwards. This process is called dy- namic programming and has become very popular with be- havioral ecologists, particularly after the publication of Man-

gel and Clark's Dynamic modeling in behavioral ecology (Mangel, Marc, and Colin W. Clark. 1988. Princeton Uni-

versity Press, Princeton, New Jersey). Houston and McNa- mara's book is not meant to replace or compete with this book; rather it extends it by showing the many problems that can be tackled using dynamic programming.

The first two chapters introduce the general problem and the proposed approach. These introductory chapters are a lucid overview of the method developed throughout the rest of the book. The authors take it for granted that a state-

dependent approach is desirable. While I agree with them , it would have been nice to be given some specific examples

June 2000 June 2000 1759 1759

This content downloaded from 169.229.32.137 on Thu, 8 May 2014 19:40:59 PMAll use subject to JSTOR Terms and Conditions